- Email: [email protected]
The reliability and validity of assessing medio-lateral patellar position: a systematic review
Manual Therapy 14 (2009) 355–362
Contents lists available at ScienceDirect
Manual Therapy journal homepage: www.elsevier.com/math
Systematic Review
The reliability and validity of assessing medio-lateral patellar position: a systematic review Toby O. Smith a, *, Leigh Davies a, Simon T. Donell b a
Orthopaedic Physiotherapy Research Unit, Physiotherapy Department – Out-Patients East, Norfolk and Norwich University Hospital, Colney Lane, Norwich, NR4 7UY, UK b Faculty of Health, University of East Anglia, Norwich, NR4 7TJ, UK
a r t i c l e i n f o
a b s t r a c t
Article history: Received 14 May 2008 Received in revised form 18 July 2008 Accepted 2 August 2008
Medio-lateral patellar position is regarded as a sign of patellofemoral pain syndrome and patellar instability. Its assessment is important in accurately performing patellofemoral therapeutic taping techniques. The purpose of this paper is to systematically review the literature to determine the reliability and validity of evaluating medio-lateral patellar position. An electronic database search was performed accessing AMED, British Nursing Index, CINAHL, the Cochrane database, EMBASE, Ovid Medline, Physiotherapy Evidence Database (PEDro), PubMed and Zetoc to July 2008. Conference proceedings and grey literature were also scrutinised for future publications. All human subject, clinical trials, assessing the inter- or intra-tester reliability, or the criterion validity, were included. A CASP tool was employed to evaluate methodological quality. Nine papers including 237 patients (306 knees) were reviewed. The findings of this review suggest that the intra-tester reliability of assessing medio-lateral patellar position is good, but that inter-tester reliability is variable. The criterion validity of this test is at worse moderate. These are based on a limited evidence-base. Further study is recommended to compare the McConnell (1986) [McConnell J. The management of chondromalacia patellae: a long term solution. Australian Journal of Physiotherapy 1986;32(4):215–23] and Herrington (2002) [Herrington LC. The inter-tester reliability of a clinical measurement used to determine the medial/lateral orientation of the patella. Manual Therapy 2002;7(3):163–7] methods of assessing medio-lateral patellar position in patients with well-defined patellofemoral disorders. Ó 2008 Elsevier Ltd. All rights reserved.
Keywords: Assessment Patellar position Reliability Validity
1. Introduction The aetiology of patellofemoral pain syndrome (PFPS) and patellar instability are multi-factorial (Sutlive et al., 2004). One factor indicated in both patellofemoral disorders is abnormal patellar tracking. The patella in said to be frequently lateralised in both disorders (Mizuno et al., 2001). It is hypothesised that this can cause an increase in retropatellar pressure over the articular surfaces, contributing to articular cartilage degeneration and subsequent pain (Powers et al., 1999; Ota et al., 2006; Fulkerson and Shea, 1990; Hughston, 1968; Insall, 1979). Similarly, patellar maltracking within the femoral sulcus can cause instability symptoms, and predispose the patella to dislocation (Arendt et al., 2002). Taping is one physiotherapeutic strategy aimed at correcting patellar mal-tracking (Warden et al., 2008). This has gained widespread acceptance as a viable treatment option for patients with
* Corresponding author. Tel.: þ44 1603 286990; fax: þ44 1603 287369. E-mail address: [email protected] (T.O. Smith). 1356-689X/$ – see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.math.2008.08.001
PFPS and patellar instability (Powers et al., 1999; McConnell, 1986, 2007). The patella is taped specifically to address the individual’s abnormal glide, rotation and tilt, and to maintain the patellar correctly within the femoral trochlea throughout range (Warden et al., 2008; Crossley et al., 2001). Since the medial and lateral translation have been associated with PFPS and patellar instability, it is important that the extent and direction of such translation can be accurately assessed. The medial and lateral displacement of the patellar can be measured by two means (Figs. 1 and 2). McConnell (1986) first described assessing this through palpation and visual estimation. She suggested that both the medial and lateral femoral epicondyles should be palpated and identified with both index fingers. The midpatellar point should then be recognised using both thumbs. In normal cases, the distance between index fingers and thumbs will be approximately equal. If the patella is laterally displaced, the distance between the index finger palpating the lateral epicondyle to thumb, will be less than the other fingers measuring the medial patellar position. This is reversed for medial displacement (McConnell, 1986). More recently, Herrington (2002) has assessed
356
T.O. Smith et al. / Manual Therapy 14 (2009) 355–362
a review of the literature suggested that such an evaluation had yet to be performed.
2. Methodology 2.1. Study eligibility criteria
Fig. 1. The McConnell (1986) approach for the assessment of medio-lateral patellar position.
this distance by marking the epicondyles and mid-patellar position on zinc tape and measuring the medial and lateral distance with a tape measure. The validity of a test is the extent to which a test measures what it is intended to measure (Edwards and Talbot, 1994; Polgar and Thomas, 2000). One aspect of validity is criterion validity. This assesses how the test under investigation compares against an established or gold-standard measure (Evans et al., 2004). In the case of patellar position, such gold-standard tests would include magnetic resonance imagery (MRI), computed tomography (CT) or plain radiographs (Grelsamer et al., 1998; Herrington, 2006; Tolouei et al., 2005). Reliability is the extent to which a test is reproducible (Polgar and Thomas, 2000; Edwards and Talbot, 1994). This is subcategorised into two types. Inter-tester reliability assesses the degree to which different examiners give consistent estimates of the same test (Portney and Watkins, 2000). Intra-tester reliability assesses the consistency of a measure on two different occasions (Polgar and Thomas, 2000; Portney and Watkins, 2000). The objective of this study is to systematically review the evidence-base to determine the inter- and intra-tester reliability and criterion validity of medio-lateral patellar position. This has considerable clinical importance given that this assessment forms the basis of therapeutic taping of the patellofemoral joint, a widely used and acceptable intervention in clinical practice for patients with patellofemoral disorders. This is further justified since
Fig. 2. The Herrington (2002) approach for the assessment of medio-lateral patellar position.
The inclusion criteria included all full text papers assessing medio-lateral patellar position by two or more examiners, at one or more time points (inter- or intra-tester reliability). Papers comparing the clinical assessment of medio-lateral patellar position to a radiological assessment using MRI, CT or plain radiograph (criterion validity) were also included. Papers of any language were included, as well as unpublished material including university theses and dissertations and conference proceedings, in an attempt to limit publication bias from impacting on this systematic review’s findings. Papers were excluded if they presented insufficient data on their method of assessing medio-lateral patellar position. Single-subject case reports, comments, letters, editorials, protocols, guidelines, or review papers were excluded. The reference lists of review papers were scrutinised for any clinical papers deemed relevant to the research question. No exclusion was made to subject age or gender. Animal and cadaver studies were excluded.
2.2. Search strategy The primary search was a search of the electronic databases AMED, British Nursing Index, CINAHL, the Cochrane database, EMBASE, Ovid Medline, Physiotherapy Evidence Database (PEDro), PubMed and Zetoc from their inception to July 2008. Key terms and Boolean operators adopted included: patella AND position; orientation. A secondary search of the following specialist journals was undertaken: Knee Surgery Sports Traumatology Arthroscopy (1993– July 2008), The Knee (1994–July 2008), the British and American editions of the Journal of Bone and Joint Surgery (1988–July 2008), American Journal of Sports Science (1988–July 2008), and Journal of Orthopaedic Sports and Physical Therapy (1991–July 2008). Unpublished or grey literature was assessed using the databases SIGLE (System for Information on Grey Literature in Europe), the National Research Register (UK), the National Technical Information Service, the British Library’s Integrated Catalogue, and Current Controlled Trials database for recently completed trials. Conference proceedings from the British Orthopaedic Association Annual Congress and British Association for Surgery of the Knee were searched from 2002 to 2008, for additional studies pertaining to this research question. Using the predefined eligibility criteria, two investigators (TS, LD) independently assessed all identified titles and abstracts. Full manuscripts of citations adhering to the criteria were ordered. Full manuscripts were ordered of those citations the reviewers were uncertain about after reading the abstracts. Reference lists from each full manuscript were scrutinised to identify any publications not initially identified. Each full text was then screened against the eligibility criteria by the same two reviewers. In cases of disagree, a census was reached through discussion. No paper was excluded on poor methodological quality. The two investigators were not blinded to the source or authors of the papers reviewed. The corresponding author of each paper included in the review was then contacted. They were asked whether they knew of any additional papers which had not been identified by the search strategy, to ensure that every paper potentially answering this research question, had been considered in this systematic review.
T.O. Smith et al. / Manual Therapy 14 (2009) 355–362
357
Articles recovered from the search strategy. (n= 1425)
Title or abstract not pertaining to the research question. (n= 1328) Abstracts which appeared relevant to the research question (n=97) Articles deemed not related to the research question after consulting the full abstract. (n= 62) Appropriate studies related to the research question, permitting full manuscripts to be ordered for further scrutiny. (n= 35)
Articles excluded as not adhering to the eligibility criteria. (n= 26) Appropriate studies related to the research question, and adhering to the eligibility criteria. (n =9) Articles excluded due to replication of] data presented. (n = 0) Final included articles. (n =9) Fig. 3. A QUORUM flow-chart.
2.3. Data extraction Data from all studies fully satisfying the eligibility criteria was entered into a spreadsheet by a single investigator (TS), and verified by a second investigator (LD). This spreadsheet tabulated:
Author names and publication date Study design Sample size Population characteristics including diagnosis, subject age and gender Method of assessing Tester details including number of tester, frequency of testing, experience of tester, teaching of tester to the measurement procedure Method of reference test for criterion validity Statistical analysis Results Any relevant methodological limitations
2.4. Critical appraisal All included papers were evaluated against an appraisal based on the Critical Appraisal Skills Programme (CASP, 2007) appraisal tool for diagnostic test studies. This appraisal tool comprises of three sections: an assessment of study validity; an evaluation of methodological quality and presentation of results; an assessment of external validity. Each paper was assessed independently by two reviewers (TS, LD). Any differences in appraisal results were settled
through discussion. There was a difference between the reviews over six items, in two papers (Tomsich et al., 1996; Fitzgerald and McClure, 1995), which was resolved by discussion. 3. Results 3.1. Search results Fig. 3 outlines the results of the search strategy. The search yielded 1425 articles whose titles and abstracts were read. Of these, 9 studies met the eligibility criteria, these are summarised in Tables 1 and 2. The papers have been subdivided by their study aims and discussed below. A total of 213 patients and 282 knees were reviewed. This included 29 patients (37 knees) diagnosed as PFPS, and 104 patients (164 knees) asymptomatic control subjects. One paper did not specify the pathology of its sample, whilst 76 patients (77 knees) were collectively assessed as general knee pathologies. Eighty-four males, and 137 females were reviewed, whilst three studies did not specify the gender of their cohorts. In those with patellofemoral disorders, the age of subjects ranged from 18 to 41 years, with a mean of 30.6 years. This differed from the asymptomatic samples where age ranged from 18 to 28 years, with a mean of 24.2 years. As expected, the method for assessing medio-lateral patellar position was made using two techniques. The majority of studies assessed patellar position following McConnell’s (1986) method. Only Tomsich et al. (1996) assessed patellar orientation differently using visual estimation or pluri-cal callipers. There was some variability in assessment position using this method. McEwan et al. (2007), Herrington (2008), Herrington (2002), Herrington et al.
358
T.O. Smith et al. / Manual Therapy 14 (2009) 355–362
Table 1 Summary of the papers included in this systematic review. Study Design Sample size Population
Medial/lateral position test
Reliability assessment Validity assessment Tester details
Statistical analysis Study Design Sample size Population
Medial/lateral position test
Reliability assessment Validity assessment Tester details Statistical analysis Study Design Sample size Population Medial/lateral position test
Reliability assessment Validity assessment
Tester details
Statistical analysis Study Design Sample size Population
Fitzgerald and McClure (1995) Observational 66 (66 knees) 66 symptomatic subjects; 31 males, 35 females; mean age 29.7 13.1 years (range 14–74); mean weight 73.4 19.6 kg; mean height 171.2 10.2 cm 40 diagnosed with patellar pain syndrome, anterior knee pain, chondromalacia patellae, subluxing patellar, patellar tendonitis or patellar fracture 26 diagnosed with meniscal pathology, ligamentus pathology, femoral or tibia fracture Subjects excluded if they had received a surgical procedure specifically to realign the patella (e.g. lateral retinacular release) McConnell assessment: subject supine, tibiofemoral joint in full extension, quadriceps contraction or lower limb rotation not documented. Palpation of the medial and lateral femoral epicondyles with the index finger and simultaneously palpating the mid-patellar with the thumbs. Normally. Distance between the fingers and thumb should be equal. If a lateral displacement is present, the distance between the index finger palpating the lateral epicondyle to the thumbs will be less than the distance from the fingers palpating the medial epicondyle to the thumbs. If a medial displacement is evident, the distance between the medial epicondyle to the thumbs will be less than the distance from the lateral eipcondyle to the thumbs Subjects were independently assessed once, by 2 different examiners, most often during the same clinic session Not assessed 12 physical therapists from 4 clinics who frequently treat patients with knee or patellofemoral disorders. All testers were familiar with the patellar orientation test prior to participation in the study. One tester had learnt the patellar orientation test from McConnell’s course. The other tester had learnt the test from colleges or from reading texts on the method of assessment. For this study, each tester received a written and photographic description of how to perform the tests based on McConnell (1986). This was provided approximately 2 weeks prior to testing Inter-tester reliability, kappa Herrington (2008) Observational, matched pairs 24 (24 knee) 12 asymptomatic subjects; 12 females; mean age 21.6 2.8 years (range 18–25); mean body mass 62.3 8.4 kg 12 subjects diagnosed with patellofemoral pain syndrome for at least 1 month; 12 females; mean age 21.6 2.6 years (range 18–25); mean body mass 64.5 9.3 kg Subjects were excluded if they had reported previous knee surgery or arthritis, history of patellar dislocation, subluxation or ligament laxity, patellar tendonopathy, chondral damage, spinal referred pain, lower limb abnormalities such as leg length discrepancy (>2 cm), were taking medication as part of their knee treatment, or had received previous knee physiotherapy and acupuncture treatment within the previous 30 days McConnell (1986) and Herrington and Nester (2004) assessment: subject general position, quadriceps contraction or lower limb rotation not documented, knee in 20 degrees flexion. Centre of patella, medial and lateral femoral epicondyle marked on a piece of folded zinc oxide tape placed on subject’s knee. Distance between the medial epidcondyle to mid-point of patella, and lateral epicondyle to mid-point of patella measured .. Not stated what used to measure distances. An assessor marked these distances on the zinc oxide tape, and a second assessor blinded to diagnosis, measured the distance between the markings. This whole procedure was repeated 3 times, with the average of the 3 measurement recorded This procedure was then repeated to assess the 12 matched control subjects on a separate occasion 1–2 days after the original measurement Not assessed The physiotherapist identifying the relevant bony landmarks and marking the zinc oxide tape was an experienced physical therapist. Details for the independent assessor blinded to diagnosis, who measured the markings, was not documented Intra-tester reliability, ICC AND SEM Herrington (2002) Observational 1 (1 knee) 1 subjects; pathology, gender, age not specified McConnell (1986) assessment: subject general position, quadriceps contraction or lower limb rotation not documented, knee in 20 degrees flexion. Centre of patella, medial and lateral femoral epicondyle marked on a piece of folded zinc oxide tape placed on subject’s knee. Distance between the medial epidcondyle to mid-point of patella, and lateral epicondyle to mid-point of patella measured .. Not stated what used to measure distances. Each assessor repeated this procedure 3 times each, re-palpating and applying tape on each occasion. Average of the 3 measurement recorded This procedure was then repeated to assess the subject on 2 separate occasions. Not specified how long duration was between assessments MRI assessment of medial/lateral patellar position with patient supine, in 20 degrees knee flexion, no details on limb rotation. Medio-lateral position determined by assessing lateral patellar displacement in relation to femoral condyles. LPD measured 3 times, with average taken. Not specified which MRI slice used to assess LPD Clinical test: medio-lateral patella orientation measured by 20 chartered physiotherapists, experience musculoskeletal physiotherapists at MACP examination approved level, and a minimum of 5 years specialising in musculoskeletal physiotherapy. Details for this assessor on experience of this test or of teaching of this technique were not detailed. MRI test: all made from one investigator blinded to the clinical examination findings Inter-tester reliability and criterion validity, means of the ICC
Reliability assessment Validity assessment Tester details Statistical analysis
Herrington and Nester (2004) Observational 10 (20 knees) 10 asymptomatic, gender, age not specified Asymptomatic described as physically active asymptomatic individuals with no history of lower limb, spinal or neurological injury Herrington (2002) assessment: subject general position, quadriceps contraction or lower limb rotation not documented, knee in 20 degrees flexion. Centre of patella, medial and lateral femoral epicondyle marked on a piece of folded zinc oxide tape placed on subject’s knee. Distance between the medial epidcondyle to mid-point of patella, and lateral epicondyle to mid-point of patella measured .. Not stated what used to measure distances. Each assessor repeated this procedure 3 times each, re-palpating and applying tape on each occasion. Average of the 3 measurement recorded This procedure was then repeated to assess the subjects on 2 separate occasions. Not specified how long duration was between assessments Not assessed Not documented Intra-tester reliability, ICC and SEM
Study Design
Herrington et al. (2006) Observational
Medial/lateral position test
T.O. Smith et al. / Manual Therapy 14 (2009) 355–362
Sample size Population Medial/lateral position test
Reliability assessment Validity assessment Tester details Statistical analysis Study Design Sample size Population Medial/lateral position test
Reliability assessment Validity assessment
Tester details
Statistical analysis Study Design Sample size Population
Medial/lateral position test
Reliability assessment Validity assessment Tester details Statistical analysis Study Design Sample size Population Medial/lateral position test
Reliability assessment Validity assessment Tester details Statistical analysis Study Design Sample size Population
359
5 (5 knees) 5 asymptomatic subjects; males/females not specified; mean age not specified Asymptomatic described as physically active asymptomatic individuals McConnell (1986) and Herrington (2002) assessment: subject general position, quadriceps contraction or lower limb rotation not documented, knee in 20 degrees flexion. Centre of patella, medial and lateral femoral epicondyle marked on a piece of folded zinc oxide tape placed on subject’s knee. Distance between the medial epidcondyle to mid-point of patella, and lateral epicondyle to mid-point of patella measured .. Not stated what used to measure distances. 1 assessor repeated this procedure 3 times each, re-palpating and applying tape on each occasion. Average of the 3 measurement recorded This procedure was then repeated to assess the subjects on 2 separate occasions. Not specified how long duration was between assessments Not assessed Clinical test: all measures taken by 1 assessor, Details for this assessor on experience of this test or of teaching of this technique was not detailed Intra-tester reliability, means of the ICC and SEM McEwan et al. (2007) Observational 24 (24 knees) 24 asymptomatic subjects; 16 males, 8 females; mean age 24.5 7.9 years, range 18–42 years Asymptomatic consist of no current or previous history of knee or lower extremity injury McConnell (1986) and Herrington and Nester (2004) assessment: subject general position, quadriceps contraction or lower limb rotation not documented, knee in 20 degrees flexion. Centre of patella, medial and lateral femoral epicondyle marked on a piece of folded zinc oxide tape placed on subject’s knee. Distance between the medial epidcondyle to mid-point of patella, and lateral epicondyle to mid-point of patella measured Not stated with what measured. 2 assessors repeated this procedure 3 times each, re-palpating and applying tape on each occasion. Average of the 3 measurement recorded This procedure was then repeated 1 day later to assess the subjects on 2 separate occasions MRI assessment of medial/lateral patellar position with patient supine, in 20 degrees knee flexion, no details on limb rotation. Medio-lateral position determined by assessing lateral patellar displacement in relation to femoral condyles. LPD measured 3 times, with average taken. Not specified which MRI slice used to assess LPD Clinical test: all measures taken by 2 independent assessor. Details for 1 assessor provided as a musculoskeletal physiotherapist with 15 years experience, not specified how long undertaken this testing procedure, or details of teaching of this technique to the assessor. MRI test: all made by one investigator blinded to the clinical examination findings Intra-tester reliability, means of the ICC criterion validity, Pearson’s product moment Powers et al. (1999) Observational 24 (38 knees) Intra-tester assessment: 10 subjects (20 knees) asymptomatic; 4 males, 6 females; mean age 26 2 years. Asymptomatic consisted of pain-free status, not specified of what Criterion validity: 4 subjects (7 knees) asymptomatic – unspecified criteria. 10 subjects (11 knees) symptomatic – described as either tibiofemoral joint osteoarthritis, anterior knee pain, meniscal injury – not specified how these diagnoses were determined. In total: 10 females, 4 males; mean age 41 16 years McConnell (1986) assessment: subject supine, knee extended, quadriceps relaxed, limb rotation not documented. Centre of patellar determined and marked, with a soft tape measure, and bisecting the distance between the most medial and lateral borders of the patella. Distance from centre of patellar to medial femoral epicondyle, and from centre of patella to lateral femoral epicondyle was then assessed using the tape measure 4 measurements of medial/lateral position median and averaged, 2 for medial and 2 for lateral femoral epicondyle distance. Measurements made on 2 separate occasions at least 2 weeks apart MRI assessment of medial/lateral patellar position with patient supine, full extension with quadriceps relaxed, in natural limb rotation for each patient (10–15 degrees external rotation). The image containing the largest patellar cross-section (mid-patellar slice) was used for analysis Clinical test: all measures taken by 1 assessor, who had less than 1 year’s experience of this technique. MRI test: all made by one investigator and measured according to procedure Intra-tester reliability, ICC criterion validity, ANOVA Tomsich et al. (1996) Observational 27 (27 knees) 27 asymptomatic subjects; 7 males, 20 females; mean age 21 5.5 years Asymptomatic defined as no history of knee pathology Assessed by visual estimation and pluri-cal calliper, each subject in supine position, in 0 degrees tibiofemoral flexion, quadriceps relaxed, foot position to maintain leg in neutral rotation using a KT-100 foot stabilizer. (1) Visual estimation of medio-lateral position assessed by positioning the index fingers and thumbs on the sides of the femoral epicondyles and over the patellar midpoint. The distance between the index finger and thumb medially and laterally is an estimate. (2) Medio-lateral position assessed by callipers by positioning the callipers along both femoral epicondyles, the midpoint marker on the ruler of the pluri-cal callipers was placed over the patellar midpoint. The distance between the epicondyle to the patellar midpoint, medially and laterally, was then recorded Subjects assessed 3 times each, by the three different examiners. Assessors were blinded to subject’s identification Not assessed 3 physical therapists who spent a total of 2 h practicing the measurement procedure before the study. Therapist’s ages ranged from 25 to 27 with 2.5 to 5.5 years experience of orthopaedic practice, graduating from 3 different physiotherapy schools Intra- and inter-tester reliability, kappa, ICC and SEM Watson et al. (1999) Observational 56 (101 knees) 56 subjects; 22 males, 34 females; mean age 29 8.0, range 22–34 years 39 (76 knees) asymptomatic subjects mean age 28 6.2 17(25 knees) symptomatic subjects mean age 30 11.4 Asymptomatic defined as no knee pain or pathology Symptomatic defined as patellofemoral pain classified as patellofemoral joint pain reproducible following at least 2 of the following activities in the last month: ascending or descending stairs, prolonged sitting, squatting Subjects excluded if they had a history of knee surgery or patellar dislocation, or if there was evidence on clinical examination of knee ligamentus injury, meniscal injuries, patellar tendonopathy, major joint effusion or plica syndrome (continued on next page)
360
T.O. Smith et al. / Manual Therapy 14 (2009) 355–362
Table 1 (continued) Medial/lateral position test
Reliability assessment Validity assessment Tester details Statistical analysis
McConnell assessment: subject supine, tibiofemoral joint in full extension and femur parallel to the plinth, quadriceps relaxed through lower limb rotation not documented. Distance measured using a tape measure from the mid-patella to the medial femoral epicondyle and to the lateral femoral epicondyle. The midpoint was determined on visual estimation, and marked with a grease pencil. A score of 0 was allocated if the distance from the medial epicondyle to the mid-patella point was equal to the distance from the lateral epicondyle to mid-patella; 1 was allocated if the distance from the medial epicondyle to the mid-patella point was >0.5 cm from the lateral epicondyle to mid-patella Subjects assessed once, by 2 different examiners, on 2 separate occasions, 3–7 days after the initial measure. Assessors were blinded to whether subjects had knee pain Not assessed 2 senior physical therapy students who had received approximately 2 h of didactic instructions and 2 h of practice on the McConnell patellofemoral classification system of medio-lateral position Intra- and inter-tester reliability, kappa
ANOVA, analysis of variance; ICC, intra-class correlation coefficient; LPD, lateral patellar displacement; MACP, Manipulation Association of Chartered Physiotherapists; MRI, magnetic resonance imaging; SEM, standard error of the measurements.
(2006) and Herrington and Nester (2004) assessed the knee in 20 degrees flexion, whereas Powers et al. (1999), Tomsich et al. (1996), Fitzgerald and McClure (1995) and Watson et al. (1999) assessed the knee in full extension. Lower limb rotation was only documented as controlled in Tomsich et al.’s (1996) study in neutral. Only Watson et al. (1999), Tomsich et al. (1996), and Powers et al. (1999) acknowledged that the quadriceps muscles were relaxed during testing.
3.2. Reliability Intra-tester reliability of medio-lateral patellar position as assessed in seven studies. Six studies reported either substantial or near perfect agreement between assessment periods, with intraclass coefficient (ICC)/kappa results ranging from 0.70 to 0.99. Four studies all reported almost perfect agreement between test procedures in McEwen et al. (2007), Powers et al. (1999), Herrington et al. (2006), and Herrington and Nester’s (2004) results. Only Watson et al.’s (1999) study reported poor to fair agreement with 0.11–0.35 kappa results. Four studies assessed inter-tester reliability. These studies reported differing results. Two studies reported near perfect agreement in Herrington (2002) results with 0.91 and 0.94. In contrast, Tomsich et al. (1996), Fitzgerald and McClure (1995) and Watson et al. (1999) reporting poor agreement with results of 0.14, 0.10 and 0.02 respectively.
3.3. Criterion validity The criterion validity of assessment of medio-lateral patellar orientation was evaluated in studies by Herrington (2002), McEwan et al. (2007) and Powers et al. (1999). These studies reported variable agreement between clinical medio-lateral patellar position assessment and MRI evaluation. Herrington (2002) reported near perfect agreement between the measures with an ICC of 0.9. McEwan et al. (2007) reported substantial agreement with an ICC of 0.61, whilst Powers et al. (1999) reported moderate agreement with an ICC of 0.44. 3.4. Critical appraisal results The findings of the CASP appraisal are presented in Table 3. These suggest that the methodological quality of the papers was limited in a number of areas. The CASP review highlighted that all studies stated appropriate research questions and applied suitable study designs to answer their research questions. As Table 1 outlines, three studies used a references test (MRI) to assess the criterion validity of the medio-lateral patella position. Only McEwan et al. (2007) stated that assessors were blinded to the results of this test, whilst Herrington (2002) indicated that different assessors were used for their MRI and clinical findings. Population characteristics such as patient’s knee history and pathology, gender, age or weight and height were poorly described in five papers. Whilst all papers identified the basic method of assessing medio-lateral patellar
Table 2 Summary of results from studies included in this systematic review. Author (date)
Mean clinically assessed medio-lateral position in mm (SD)
Mean reference test medio-lateral position (SD)
Inter-tester reliability (ICC with SEM)
Intra-tester reliability (ICC with SEM)
Criterion validity ICC (p value)
Fitzgerald and McClure (1995) Herrington (2008)
N/D
N/A
0.10 (44%)a
N/A
N/A
PFPS group: lateral 7.5 (2.6); asymptomatic group: lateral 3.8 (2.4) Medial 8.98 (0.51); lateral 8.35 (0.66)
N/A
N/A
0.86, SEM 0.2 mm
N/A
LPD 5.0(2.8)
N/A
0.9
3 mm (6 mm) lateralised from central Medial females 2.5 (1.8)/males 2.3 (1.8); lateral females 6.6 (4.5)/males 5.9 (4.5) Medial 8.9 (0.1); lateral 8.3 (0.1) 6.8 9.6% lateral displacement as percentage of patella width
N/A
Medial measure 0.91; lateral measure 0.94 N/A
0.99 (p < 0.01), SEM 6 mm
N/A
N/A
N/A
0.99 (p < 0.015), SEM 0.1 mm
N/A
LPD 8.1 (2.8) 16.1 12.3% lateral displacement as percentage of patella width N/D N/A
N/A N/A
0.86 (0.1, CI 8.1–8.5) 0.91
0.61 (p ¼ 0.002) 0.44
0.14 (0.55) 0.02 (70%)a
0.70 (0.28) 0.11 (8.4) to 0.35 (0.74)a
N/A N/A
Herrington (2002)
Herrington et al. (2006) Herrington and Nester (2004) McEwan et al. (2007) Powers et al. (1999)
Tomsich et al. (1996) Watson et al. (1999)
N/D Frequency between testers of: score 0, 135–149; score 1, 47–53
ICC, intra-class correlation co-efficient; N/D, not documented; mm, millimetres; SD, standard deviation; N/A, not assessed; SEM, standard error of the measurements. a Kappa coefficient (percentage of agreement).
T.O. Smith et al. / Manual Therapy 14 (2009) 355–362
361
Table 3 A summary of the CASP results. CASP factors
Fitzgerald and McClure (1995)
Herrington Herrington Herrington (2008) (2002) et al. (2006)
Herrington and Nester (2004)
McEwan Powers Tomsich Watson et al. (2007) et al. (1999) et al. (1996) et al. (1999)
Clearly focused question stated Appropriate design Appropriate reference test available Did all receive reference and diagnostic test Could reference test findings influence diagnostic test result Population characteristics clearly defined Diagnostic test clearly defined Appropriate results analysis Precise statistical results presented Appropriate interpretation Ability to generalise results Were the results applicable to clinical practice
Y Y N
Y Y N
Y Y Y
Y Y N
Y Y N
Y Y Y
Y Y Y
Y Y N
Y Y N
N
N
Y
N
N
Y
Y
N
N
N/A
N/A
N
N/A
N/A
N
Y
N/A
N/A
N
Y
N
N
N
Y
Y
Y
Y
N Y N
N Y N
N Y N
N Y N
N Y N
N Y Y
N Y N
Y Y N
N Y N
Y Y Y
Y Y Y
Y N N
N N N
N N N
Y N N
Y Y Y
N N N
Y Y Y
Y, yes; N, no; N/A, not applicable.
position, all studies except Tomsich et al. (1996) did not clearly state either the position of the knee or lower limb, or whether the quadriceps were relaxed or contracted, confounding variables in assessing medio-lateral patellar position. The evidence-base used appropriate statistical tests with ICC and kappa analysis, but only McEwan et al. (2007) documented confidence intervals to assess the precision of their statistical findings. Since only Fitzgerald and McClure (1995), Powers et al. (1999), Watson et al. (1999) and Herrington (2008) recruited patients with patellofemoral pathology, only these studies were regarded as having any clinical significance to be generalisable to the clinic setting. 4. Discussion The findings of this review suggest that the intra-tester reliability of medio-lateral position tests is good, but that inter-tester reliability is variable. The criterion validity of these tests is at worst moderate. However, such conclusions should be interpreted with caution since the evidence-base presently exhibits a number of limitations. The two most important weaknesses identified were the poor documentation of the actual medio-lateral patella positioning test methods and the limited description of subject characteristics. Two distinct methods of assessing medio-lateral patellar position were recognised (Figs. 1 and 2). This review would suggest that Herrington’s (2002) methods appears to have better inter-tester reliability and criterion validity than McConnell’s (1986). This difference may account for the substantial difference in intra-tester results between the findings of Watson et al. (1999) and Herrington et al. (2006) and Herrington and Nester (2004), or inter-tester findings between Tomsich et al. (1996) and Herrington (2002). However, this cannot be categorically stated given the limited size of evidence presently available. Furthermore, with the exception of 12 subjects in Herrington’s (2008) study, all other studies which assessed Herrington’s (2002) method were undertaken on asymptomatic populations. As a result, it is not possible to generalise with confidence, these results to patients with patellofemoral disorders. Accordingly, a direct comparison of these two methods of assessing medio-lateral position is warranted to determine the optimal method of assessing patients with different patellofemoral disorders. A considerable weakness in the evidence-base is the poor description of the medio-lateral patellar position test. Studies did not demonstrate whether they controlled confounding factors such
as lower limb rotation, quadriceps contraction or knee flexion (McEwan et al., 2007; Herrington et al., 2006; Herrington, 2002, 2008; Herrington and Nester, 2004; Fitzgerald and McClure, 1995). These variables can influence the patellar position within the trochlear groove (Herrington and Pearson, 2008; Muhle et al., 1999). Variations in these factors between study methodologies may account for the differences in results between studies for intertester reliability. This should be considered when presenting the findings of similar studies in the future. The degree of knee flexion may be an important factor. Five papers (McEwan et al., 2007; Herrington et al., 2006; Herrington, 2002, 2008; Herrington and Nester 2004) assessed the knee in 20 degrees flexion, compared to full extension. Considering the patella engages with the femoral trochlear at approximately 10–30 degrees of knee flexion (Beasley and Vidal, 2004; Senavongse et al., 2003), it may be hypothesised that the good reliability results of these studies may be related to greater patellar osseous constraint compared to full extension. Further study may therefore be indicated to investigate this assumption assessing medio-lateral patellar position in full extension compared to difference ranges of tibiofemoral flexion. The papers reviewed poorly documented important subject characteristics, particularly in view of weight and height. Papers poorly distinguished between those subjects with patellar instability, patellofemoral pain syndrome or other patellofemoral disorders. Consequently, it was not possible to ascertain the heterogeneity of these papers. In response to this, it was deemed unstable to formally compare these paper’s results using a metaanalysis design. In addition, Egger et al. (2001) suggested that meta-analysis should not be undertaken for observational studies, which was the methodology design used in all the studies reviewed. It appeared that only Fitzgerald and McClure (1995) assessed medio-lateral patellar position in patients with subluxed patellar. The present evidence-base does not state whether the reliability or validity of this test is related to the severity of patellar displacement. Further study is recommended to investigate whether the accuracy of these measurements is related to the degree of patellar displacement in well-defined populations. With the exception of Herrington (2008), Herrington and Nester (2004) and Herrington et al. (2006), the assessors’ experience of the medial-lateral patellar position tests was well described. The assessors in each study appeared to have broadly similar levels of experience and training in each assessment method. However, it remains unclear whether the reliability or validity of the tests to
362
T.O. Smith et al. / Manual Therapy 14 (2009) 355–362
assess medio-lateral position is dependent on the method of teaching these measures. This may inform clinicians as to whether attendance at courses is warranted, or whether text and photographic teaching is sufficient to accurately assess this measurement. The results of this review would suggest that the intra-tester reliability of medio-lateral patellar orientation tests are satisfactory. Accordingly, clinicians can have some confidence that they have consistency in their measures between treatment sessions. It remains unclear whether the results of this measure are reproducible if patients change from one physiotherapist to another with such variable inter-tester reliability. Furthermore, further study is indicated to determine the clinical relevance of these findings. The reliability of physiotherapist’s abilities to translate their mediolateral displacement findings to specific taping placement to address abnormal patellar translation is presently unclear and should be addressed with future study. Although studies frequently described the age and gender of their subjects, only Fitzgerald and McClure (1995) and Herrington (2008) detailed the weight of their subjects to indicate body mass. Body mass may have influenced medio-lateral patellar position measurements. Fitzgerald and McClure (1995) acknowledged that it appeared more difficult to palpate the bony landmarks in those subjects with greater body mass. Accordingly, this may have contributed to variability in the measurement of these patients, and an additional variable which should be considered. 5. Conclusions The findings of this study indicate that the intra-tester reliability of medio-lateral patellar position tests are good, but that intertester reliability is variable. The criterion validity of these tests is at worse moderate. These are based on a limited evidence-base. Further study is recommended to compare the McConnell (1986) and Herrington (2002) methods of assessing medio-lateral patellar orientation. After this rigorous assessment, clinicians will then be better informed on the appropriateness of these tests when assessing patellar orientation in patients with patellofemoral disorders. Acknowledgements We thank the library staff at the Norfolk and Norwich University Hospital’s Sir Benjamin Gooch Library for their assistance in paper retrieval. We also thank Mr Mark Rowlands for his assistance with the photographs used in this paper. References Arendt EA, Fithian DC, Cohen E. Current concepts of lateral patella dislocation. Clinical Sports Medicine 2002;21:499–519. Beasley LS, Vidal AF. Traumatic patellar dislocation in children and adolescents: treatment update and literature review. Current Opinion in Paediatrics 2004;16:29–36. Critical Skills Appraisal Programme (CASP) Homepage on the Internet. Oxford, UK: Learning & Development Public Health Resource Unit; c. 2007. Available from: http://www.phru.nhs.uk/casp/critical_appraisal_tools.htm (accessed 1 May 2007). Crossley K, Bennell K, Green S, McConnell J. A systematic review of physical interventions for patellofemoral pain syndrome. Clinical Journal of Sports Medicine 2001;11(2):103–10.
Edwards A, Talbot R. The hard pressed researcher. A research handbook for the caring professions. London: Longman; 1994. Egger M, Davey Smith G, Schneider M. Systematic reviews of observational studies. In: Egger M, Davey Smith G, Altman DG, editors. Systematic reviews in health care. London: BMJ Books; 2001. p. 211–28. Evans R, Elwyn G, Edwards A. Review of instruments for peer assessment of physicians. BMJ 2004;328:1240. Fitzgerald GK, McClure PW. Reliability of measurements obtained with four tests for patellofemoral alignment. Physical Therapy 1995;75(2):84–92. Fulkerson JP, Shea KP. Disorders of patellofemoral alignment. Journal of Bone and Joint Surgery 1990;72-A:1424–9. Grelsamer RP, Newton PM, Staron RB. The medial-lateral position of the patella on routine magnetic resonance imaging: when is normal not normal? Arthroscopy 1998;14:23–8. Herrington LC. The inter-tester reliability of a clinical measurement used to determine the medial/lateral orientation of the patella. Manual Therapy 2002;7(3):163–7. Herrington L. The effect of corrective taping of the patella on patella position as defined by MRI. Research in Sports Medicine 2006;14:215–23. Herrington LC. The difference in a clinical measure of patella lateral position between individuals with patellofemoral pain and matched controls. Journal of Orthopaedic and Sports Physical Therapy 2008;38:59–62. Herrington L, Nester C. Q-angle undervalued? The relationship between Q-angel and medio-lateral position of the patella. Clinical Biomechanics 2004;19: 1070–3. Herrington L, Pearson S. The applicability of ultrasound imaging in the assessment of dynamic patella tracking: a preliminary investigation. The Knee 2008;15(2):125–7. Herrington L, Rivett N, Munro S. The relationship between patella position and length of the iliotibial band as assessed using Ober’s test. Manual Therapy 2006;11:182–6. Hughston JC. Subluxation of the patella. Journal of Bone and Joint Surgery 1968;50-A:1003–26. Insall J. Chondromalacia patellae: patellar malalignment syndrome. Orthopedic Clinics of North America 1979;10:117–27. McConnell J. The management of chondromalacia patellae: a long term solution. Australian Journal of Physiotherapy 1986;32(4):215–23. McConnell J. Rehabilitation and nonoperative treatment of patellar instability. Sports Medicine and Arthroscopy Reviews 2007;15:95–104. McEwan I, Herrington L, Thom J. The validity of clinical measures of patella position. Manual Therapy 2007;12:226–30. Mizuno Y, Kumagai M, Mattessich SM, Eilas JJ, Ramrattan N, Cosgarea AJ, et al. Q-angle influences tibiofemoral and patellofemoral kinematics. Journal of Orthopaedic Research 2001;19:834–40. Muhle C, Brossmann J, Heller M. Kinematic CT and MR imaging of the patellofemoral joint. European Radiology 1999;9(3):508–18. Ota S, Ward SR, Chen T-J, Tsai Y-J, Powers CM. Concurrent criterion-related validity and reliability of a clinical device used to assess lateral patellar displacement. Journal of Orthopaedic and Sports Physical Therapy 2006;36(9):645–52. Polgar S, Thomas SA. Introduction to research in the health sciences. 4th ed. London: Churchill Livingstone; 2000. Portney LG, Watkins MP. Foundations of clinical research. Applications to practice. 2nd ed. New Jersey: Prentice Hall; 2000. Powers CM, Mortenson S, Nishimoto D, Simon D. Criterion-related validity of a clinical measurement to determine the medial/lateral component of patellar orientation. Journal of Orthopaedic and Sports Physical Therapy 1999;29(7):372–7. Senavongse W, Farahmand F, Jones L, Andersen H, Bull AM, Amis AA. Quantitative measurement of patellofemoral joint stability: force-displacement behaviour of the human patella in vitro. Journal of Orthopaedic Research 2003;21:780–6. Sutlive TG, Mitchell SD, Maxfield SN, McLean CL, Neumann JC, Swiecki CR, et al. Identification of individuals with patellofemoral pain whose symptoms improved after a combined program of foot orthosis use and modified activity: a preliminary investigation. Physical Therapy 2004;84(1):49–61. Tolouei FM, Afshar A, Salarilak S, Sina A. CT patellar cortex tilt angle: a radiological method to measure patellar tilt. Iran Journal of Radiology 2005;3(1):17–21. Tomsich DA, Nitz AJ, Threlkeld AJ, Shapiro R. Patellofemoral alignment: reliability. Journal of Orthopaedic and Sports Physical Therapy 1996;23(3):200–8. Warden SJ, Hinman RS, Watson Jr MA, Avin KG, Bialocerkowski AE, Crossley KM. Patellar taping and bracing for the treatment of chronic knee pain: a systematic review and meta-analysis. Arthritis and Rheumatology 2008;15(1):73–83. Watson CJ, Propps M, Galt W, Redding A, Dobbs D. Reliability of McConnell’s classification of patellar orientation in symptomatic and asymptomatic subjects. Journal of Orthopaedic and Sports Physical Therapy 1999;29(7):378–85.
Contents lists available at ScienceDirect
Manual Therapy journal homepage: www.elsevier.com/math
Systematic Review
The reliability and validity of assessing medio-lateral patellar position: a systematic review Toby O. Smith a, *, Leigh Davies a, Simon T. Donell b a
Orthopaedic Physiotherapy Research Unit, Physiotherapy Department – Out-Patients East, Norfolk and Norwich University Hospital, Colney Lane, Norwich, NR4 7UY, UK b Faculty of Health, University of East Anglia, Norwich, NR4 7TJ, UK
a r t i c l e i n f o
a b s t r a c t
Article history: Received 14 May 2008 Received in revised form 18 July 2008 Accepted 2 August 2008
Medio-lateral patellar position is regarded as a sign of patellofemoral pain syndrome and patellar instability. Its assessment is important in accurately performing patellofemoral therapeutic taping techniques. The purpose of this paper is to systematically review the literature to determine the reliability and validity of evaluating medio-lateral patellar position. An electronic database search was performed accessing AMED, British Nursing Index, CINAHL, the Cochrane database, EMBASE, Ovid Medline, Physiotherapy Evidence Database (PEDro), PubMed and Zetoc to July 2008. Conference proceedings and grey literature were also scrutinised for future publications. All human subject, clinical trials, assessing the inter- or intra-tester reliability, or the criterion validity, were included. A CASP tool was employed to evaluate methodological quality. Nine papers including 237 patients (306 knees) were reviewed. The findings of this review suggest that the intra-tester reliability of assessing medio-lateral patellar position is good, but that inter-tester reliability is variable. The criterion validity of this test is at worse moderate. These are based on a limited evidence-base. Further study is recommended to compare the McConnell (1986) [McConnell J. The management of chondromalacia patellae: a long term solution. Australian Journal of Physiotherapy 1986;32(4):215–23] and Herrington (2002) [Herrington LC. The inter-tester reliability of a clinical measurement used to determine the medial/lateral orientation of the patella. Manual Therapy 2002;7(3):163–7] methods of assessing medio-lateral patellar position in patients with well-defined patellofemoral disorders. Ó 2008 Elsevier Ltd. All rights reserved.
Keywords: Assessment Patellar position Reliability Validity
1. Introduction The aetiology of patellofemoral pain syndrome (PFPS) and patellar instability are multi-factorial (Sutlive et al., 2004). One factor indicated in both patellofemoral disorders is abnormal patellar tracking. The patella in said to be frequently lateralised in both disorders (Mizuno et al., 2001). It is hypothesised that this can cause an increase in retropatellar pressure over the articular surfaces, contributing to articular cartilage degeneration and subsequent pain (Powers et al., 1999; Ota et al., 2006; Fulkerson and Shea, 1990; Hughston, 1968; Insall, 1979). Similarly, patellar maltracking within the femoral sulcus can cause instability symptoms, and predispose the patella to dislocation (Arendt et al., 2002). Taping is one physiotherapeutic strategy aimed at correcting patellar mal-tracking (Warden et al., 2008). This has gained widespread acceptance as a viable treatment option for patients with
* Corresponding author. Tel.: þ44 1603 286990; fax: þ44 1603 287369. E-mail address: [email protected] (T.O. Smith). 1356-689X/$ – see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.math.2008.08.001
PFPS and patellar instability (Powers et al., 1999; McConnell, 1986, 2007). The patella is taped specifically to address the individual’s abnormal glide, rotation and tilt, and to maintain the patellar correctly within the femoral trochlea throughout range (Warden et al., 2008; Crossley et al., 2001). Since the medial and lateral translation have been associated with PFPS and patellar instability, it is important that the extent and direction of such translation can be accurately assessed. The medial and lateral displacement of the patellar can be measured by two means (Figs. 1 and 2). McConnell (1986) first described assessing this through palpation and visual estimation. She suggested that both the medial and lateral femoral epicondyles should be palpated and identified with both index fingers. The midpatellar point should then be recognised using both thumbs. In normal cases, the distance between index fingers and thumbs will be approximately equal. If the patella is laterally displaced, the distance between the index finger palpating the lateral epicondyle to thumb, will be less than the other fingers measuring the medial patellar position. This is reversed for medial displacement (McConnell, 1986). More recently, Herrington (2002) has assessed
356
T.O. Smith et al. / Manual Therapy 14 (2009) 355–362
a review of the literature suggested that such an evaluation had yet to be performed.
2. Methodology 2.1. Study eligibility criteria
Fig. 1. The McConnell (1986) approach for the assessment of medio-lateral patellar position.
this distance by marking the epicondyles and mid-patellar position on zinc tape and measuring the medial and lateral distance with a tape measure. The validity of a test is the extent to which a test measures what it is intended to measure (Edwards and Talbot, 1994; Polgar and Thomas, 2000). One aspect of validity is criterion validity. This assesses how the test under investigation compares against an established or gold-standard measure (Evans et al., 2004). In the case of patellar position, such gold-standard tests would include magnetic resonance imagery (MRI), computed tomography (CT) or plain radiographs (Grelsamer et al., 1998; Herrington, 2006; Tolouei et al., 2005). Reliability is the extent to which a test is reproducible (Polgar and Thomas, 2000; Edwards and Talbot, 1994). This is subcategorised into two types. Inter-tester reliability assesses the degree to which different examiners give consistent estimates of the same test (Portney and Watkins, 2000). Intra-tester reliability assesses the consistency of a measure on two different occasions (Polgar and Thomas, 2000; Portney and Watkins, 2000). The objective of this study is to systematically review the evidence-base to determine the inter- and intra-tester reliability and criterion validity of medio-lateral patellar position. This has considerable clinical importance given that this assessment forms the basis of therapeutic taping of the patellofemoral joint, a widely used and acceptable intervention in clinical practice for patients with patellofemoral disorders. This is further justified since
Fig. 2. The Herrington (2002) approach for the assessment of medio-lateral patellar position.
The inclusion criteria included all full text papers assessing medio-lateral patellar position by two or more examiners, at one or more time points (inter- or intra-tester reliability). Papers comparing the clinical assessment of medio-lateral patellar position to a radiological assessment using MRI, CT or plain radiograph (criterion validity) were also included. Papers of any language were included, as well as unpublished material including university theses and dissertations and conference proceedings, in an attempt to limit publication bias from impacting on this systematic review’s findings. Papers were excluded if they presented insufficient data on their method of assessing medio-lateral patellar position. Single-subject case reports, comments, letters, editorials, protocols, guidelines, or review papers were excluded. The reference lists of review papers were scrutinised for any clinical papers deemed relevant to the research question. No exclusion was made to subject age or gender. Animal and cadaver studies were excluded.
2.2. Search strategy The primary search was a search of the electronic databases AMED, British Nursing Index, CINAHL, the Cochrane database, EMBASE, Ovid Medline, Physiotherapy Evidence Database (PEDro), PubMed and Zetoc from their inception to July 2008. Key terms and Boolean operators adopted included: patella AND position; orientation. A secondary search of the following specialist journals was undertaken: Knee Surgery Sports Traumatology Arthroscopy (1993– July 2008), The Knee (1994–July 2008), the British and American editions of the Journal of Bone and Joint Surgery (1988–July 2008), American Journal of Sports Science (1988–July 2008), and Journal of Orthopaedic Sports and Physical Therapy (1991–July 2008). Unpublished or grey literature was assessed using the databases SIGLE (System for Information on Grey Literature in Europe), the National Research Register (UK), the National Technical Information Service, the British Library’s Integrated Catalogue, and Current Controlled Trials database for recently completed trials. Conference proceedings from the British Orthopaedic Association Annual Congress and British Association for Surgery of the Knee were searched from 2002 to 2008, for additional studies pertaining to this research question. Using the predefined eligibility criteria, two investigators (TS, LD) independently assessed all identified titles and abstracts. Full manuscripts of citations adhering to the criteria were ordered. Full manuscripts were ordered of those citations the reviewers were uncertain about after reading the abstracts. Reference lists from each full manuscript were scrutinised to identify any publications not initially identified. Each full text was then screened against the eligibility criteria by the same two reviewers. In cases of disagree, a census was reached through discussion. No paper was excluded on poor methodological quality. The two investigators were not blinded to the source or authors of the papers reviewed. The corresponding author of each paper included in the review was then contacted. They were asked whether they knew of any additional papers which had not been identified by the search strategy, to ensure that every paper potentially answering this research question, had been considered in this systematic review.
T.O. Smith et al. / Manual Therapy 14 (2009) 355–362
357
Articles recovered from the search strategy. (n= 1425)
Title or abstract not pertaining to the research question. (n= 1328) Abstracts which appeared relevant to the research question (n=97) Articles deemed not related to the research question after consulting the full abstract. (n= 62) Appropriate studies related to the research question, permitting full manuscripts to be ordered for further scrutiny. (n= 35)
Articles excluded as not adhering to the eligibility criteria. (n= 26) Appropriate studies related to the research question, and adhering to the eligibility criteria. (n =9) Articles excluded due to replication of] data presented. (n = 0) Final included articles. (n =9) Fig. 3. A QUORUM flow-chart.
2.3. Data extraction Data from all studies fully satisfying the eligibility criteria was entered into a spreadsheet by a single investigator (TS), and verified by a second investigator (LD). This spreadsheet tabulated:
Author names and publication date Study design Sample size Population characteristics including diagnosis, subject age and gender Method of assessing Tester details including number of tester, frequency of testing, experience of tester, teaching of tester to the measurement procedure Method of reference test for criterion validity Statistical analysis Results Any relevant methodological limitations
2.4. Critical appraisal All included papers were evaluated against an appraisal based on the Critical Appraisal Skills Programme (CASP, 2007) appraisal tool for diagnostic test studies. This appraisal tool comprises of three sections: an assessment of study validity; an evaluation of methodological quality and presentation of results; an assessment of external validity. Each paper was assessed independently by two reviewers (TS, LD). Any differences in appraisal results were settled
through discussion. There was a difference between the reviews over six items, in two papers (Tomsich et al., 1996; Fitzgerald and McClure, 1995), which was resolved by discussion. 3. Results 3.1. Search results Fig. 3 outlines the results of the search strategy. The search yielded 1425 articles whose titles and abstracts were read. Of these, 9 studies met the eligibility criteria, these are summarised in Tables 1 and 2. The papers have been subdivided by their study aims and discussed below. A total of 213 patients and 282 knees were reviewed. This included 29 patients (37 knees) diagnosed as PFPS, and 104 patients (164 knees) asymptomatic control subjects. One paper did not specify the pathology of its sample, whilst 76 patients (77 knees) were collectively assessed as general knee pathologies. Eighty-four males, and 137 females were reviewed, whilst three studies did not specify the gender of their cohorts. In those with patellofemoral disorders, the age of subjects ranged from 18 to 41 years, with a mean of 30.6 years. This differed from the asymptomatic samples where age ranged from 18 to 28 years, with a mean of 24.2 years. As expected, the method for assessing medio-lateral patellar position was made using two techniques. The majority of studies assessed patellar position following McConnell’s (1986) method. Only Tomsich et al. (1996) assessed patellar orientation differently using visual estimation or pluri-cal callipers. There was some variability in assessment position using this method. McEwan et al. (2007), Herrington (2008), Herrington (2002), Herrington et al.
358
T.O. Smith et al. / Manual Therapy 14 (2009) 355–362
Table 1 Summary of the papers included in this systematic review. Study Design Sample size Population
Medial/lateral position test
Reliability assessment Validity assessment Tester details
Statistical analysis Study Design Sample size Population
Medial/lateral position test
Reliability assessment Validity assessment Tester details Statistical analysis Study Design Sample size Population Medial/lateral position test
Reliability assessment Validity assessment
Tester details
Statistical analysis Study Design Sample size Population
Fitzgerald and McClure (1995) Observational 66 (66 knees) 66 symptomatic subjects; 31 males, 35 females; mean age 29.7 13.1 years (range 14–74); mean weight 73.4 19.6 kg; mean height 171.2 10.2 cm 40 diagnosed with patellar pain syndrome, anterior knee pain, chondromalacia patellae, subluxing patellar, patellar tendonitis or patellar fracture 26 diagnosed with meniscal pathology, ligamentus pathology, femoral or tibia fracture Subjects excluded if they had received a surgical procedure specifically to realign the patella (e.g. lateral retinacular release) McConnell assessment: subject supine, tibiofemoral joint in full extension, quadriceps contraction or lower limb rotation not documented. Palpation of the medial and lateral femoral epicondyles with the index finger and simultaneously palpating the mid-patellar with the thumbs. Normally. Distance between the fingers and thumb should be equal. If a lateral displacement is present, the distance between the index finger palpating the lateral epicondyle to the thumbs will be less than the distance from the fingers palpating the medial epicondyle to the thumbs. If a medial displacement is evident, the distance between the medial epicondyle to the thumbs will be less than the distance from the lateral eipcondyle to the thumbs Subjects were independently assessed once, by 2 different examiners, most often during the same clinic session Not assessed 12 physical therapists from 4 clinics who frequently treat patients with knee or patellofemoral disorders. All testers were familiar with the patellar orientation test prior to participation in the study. One tester had learnt the patellar orientation test from McConnell’s course. The other tester had learnt the test from colleges or from reading texts on the method of assessment. For this study, each tester received a written and photographic description of how to perform the tests based on McConnell (1986). This was provided approximately 2 weeks prior to testing Inter-tester reliability, kappa Herrington (2008) Observational, matched pairs 24 (24 knee) 12 asymptomatic subjects; 12 females; mean age 21.6 2.8 years (range 18–25); mean body mass 62.3 8.4 kg 12 subjects diagnosed with patellofemoral pain syndrome for at least 1 month; 12 females; mean age 21.6 2.6 years (range 18–25); mean body mass 64.5 9.3 kg Subjects were excluded if they had reported previous knee surgery or arthritis, history of patellar dislocation, subluxation or ligament laxity, patellar tendonopathy, chondral damage, spinal referred pain, lower limb abnormalities such as leg length discrepancy (>2 cm), were taking medication as part of their knee treatment, or had received previous knee physiotherapy and acupuncture treatment within the previous 30 days McConnell (1986) and Herrington and Nester (2004) assessment: subject general position, quadriceps contraction or lower limb rotation not documented, knee in 20 degrees flexion. Centre of patella, medial and lateral femoral epicondyle marked on a piece of folded zinc oxide tape placed on subject’s knee. Distance between the medial epidcondyle to mid-point of patella, and lateral epicondyle to mid-point of patella measured .. Not stated what used to measure distances. An assessor marked these distances on the zinc oxide tape, and a second assessor blinded to diagnosis, measured the distance between the markings. This whole procedure was repeated 3 times, with the average of the 3 measurement recorded This procedure was then repeated to assess the 12 matched control subjects on a separate occasion 1–2 days after the original measurement Not assessed The physiotherapist identifying the relevant bony landmarks and marking the zinc oxide tape was an experienced physical therapist. Details for the independent assessor blinded to diagnosis, who measured the markings, was not documented Intra-tester reliability, ICC AND SEM Herrington (2002) Observational 1 (1 knee) 1 subjects; pathology, gender, age not specified McConnell (1986) assessment: subject general position, quadriceps contraction or lower limb rotation not documented, knee in 20 degrees flexion. Centre of patella, medial and lateral femoral epicondyle marked on a piece of folded zinc oxide tape placed on subject’s knee. Distance between the medial epidcondyle to mid-point of patella, and lateral epicondyle to mid-point of patella measured .. Not stated what used to measure distances. Each assessor repeated this procedure 3 times each, re-palpating and applying tape on each occasion. Average of the 3 measurement recorded This procedure was then repeated to assess the subject on 2 separate occasions. Not specified how long duration was between assessments MRI assessment of medial/lateral patellar position with patient supine, in 20 degrees knee flexion, no details on limb rotation. Medio-lateral position determined by assessing lateral patellar displacement in relation to femoral condyles. LPD measured 3 times, with average taken. Not specified which MRI slice used to assess LPD Clinical test: medio-lateral patella orientation measured by 20 chartered physiotherapists, experience musculoskeletal physiotherapists at MACP examination approved level, and a minimum of 5 years specialising in musculoskeletal physiotherapy. Details for this assessor on experience of this test or of teaching of this technique were not detailed. MRI test: all made from one investigator blinded to the clinical examination findings Inter-tester reliability and criterion validity, means of the ICC
Reliability assessment Validity assessment Tester details Statistical analysis
Herrington and Nester (2004) Observational 10 (20 knees) 10 asymptomatic, gender, age not specified Asymptomatic described as physically active asymptomatic individuals with no history of lower limb, spinal or neurological injury Herrington (2002) assessment: subject general position, quadriceps contraction or lower limb rotation not documented, knee in 20 degrees flexion. Centre of patella, medial and lateral femoral epicondyle marked on a piece of folded zinc oxide tape placed on subject’s knee. Distance between the medial epidcondyle to mid-point of patella, and lateral epicondyle to mid-point of patella measured .. Not stated what used to measure distances. Each assessor repeated this procedure 3 times each, re-palpating and applying tape on each occasion. Average of the 3 measurement recorded This procedure was then repeated to assess the subjects on 2 separate occasions. Not specified how long duration was between assessments Not assessed Not documented Intra-tester reliability, ICC and SEM
Study Design
Herrington et al. (2006) Observational
Medial/lateral position test
T.O. Smith et al. / Manual Therapy 14 (2009) 355–362
Sample size Population Medial/lateral position test
Reliability assessment Validity assessment Tester details Statistical analysis Study Design Sample size Population Medial/lateral position test
Reliability assessment Validity assessment
Tester details
Statistical analysis Study Design Sample size Population
Medial/lateral position test
Reliability assessment Validity assessment Tester details Statistical analysis Study Design Sample size Population Medial/lateral position test
Reliability assessment Validity assessment Tester details Statistical analysis Study Design Sample size Population
359
5 (5 knees) 5 asymptomatic subjects; males/females not specified; mean age not specified Asymptomatic described as physically active asymptomatic individuals McConnell (1986) and Herrington (2002) assessment: subject general position, quadriceps contraction or lower limb rotation not documented, knee in 20 degrees flexion. Centre of patella, medial and lateral femoral epicondyle marked on a piece of folded zinc oxide tape placed on subject’s knee. Distance between the medial epidcondyle to mid-point of patella, and lateral epicondyle to mid-point of patella measured .. Not stated what used to measure distances. 1 assessor repeated this procedure 3 times each, re-palpating and applying tape on each occasion. Average of the 3 measurement recorded This procedure was then repeated to assess the subjects on 2 separate occasions. Not specified how long duration was between assessments Not assessed Clinical test: all measures taken by 1 assessor, Details for this assessor on experience of this test or of teaching of this technique was not detailed Intra-tester reliability, means of the ICC and SEM McEwan et al. (2007) Observational 24 (24 knees) 24 asymptomatic subjects; 16 males, 8 females; mean age 24.5 7.9 years, range 18–42 years Asymptomatic consist of no current or previous history of knee or lower extremity injury McConnell (1986) and Herrington and Nester (2004) assessment: subject general position, quadriceps contraction or lower limb rotation not documented, knee in 20 degrees flexion. Centre of patella, medial and lateral femoral epicondyle marked on a piece of folded zinc oxide tape placed on subject’s knee. Distance between the medial epidcondyle to mid-point of patella, and lateral epicondyle to mid-point of patella measured Not stated with what measured. 2 assessors repeated this procedure 3 times each, re-palpating and applying tape on each occasion. Average of the 3 measurement recorded This procedure was then repeated 1 day later to assess the subjects on 2 separate occasions MRI assessment of medial/lateral patellar position with patient supine, in 20 degrees knee flexion, no details on limb rotation. Medio-lateral position determined by assessing lateral patellar displacement in relation to femoral condyles. LPD measured 3 times, with average taken. Not specified which MRI slice used to assess LPD Clinical test: all measures taken by 2 independent assessor. Details for 1 assessor provided as a musculoskeletal physiotherapist with 15 years experience, not specified how long undertaken this testing procedure, or details of teaching of this technique to the assessor. MRI test: all made by one investigator blinded to the clinical examination findings Intra-tester reliability, means of the ICC criterion validity, Pearson’s product moment Powers et al. (1999) Observational 24 (38 knees) Intra-tester assessment: 10 subjects (20 knees) asymptomatic; 4 males, 6 females; mean age 26 2 years. Asymptomatic consisted of pain-free status, not specified of what Criterion validity: 4 subjects (7 knees) asymptomatic – unspecified criteria. 10 subjects (11 knees) symptomatic – described as either tibiofemoral joint osteoarthritis, anterior knee pain, meniscal injury – not specified how these diagnoses were determined. In total: 10 females, 4 males; mean age 41 16 years McConnell (1986) assessment: subject supine, knee extended, quadriceps relaxed, limb rotation not documented. Centre of patellar determined and marked, with a soft tape measure, and bisecting the distance between the most medial and lateral borders of the patella. Distance from centre of patellar to medial femoral epicondyle, and from centre of patella to lateral femoral epicondyle was then assessed using the tape measure 4 measurements of medial/lateral position median and averaged, 2 for medial and 2 for lateral femoral epicondyle distance. Measurements made on 2 separate occasions at least 2 weeks apart MRI assessment of medial/lateral patellar position with patient supine, full extension with quadriceps relaxed, in natural limb rotation for each patient (10–15 degrees external rotation). The image containing the largest patellar cross-section (mid-patellar slice) was used for analysis Clinical test: all measures taken by 1 assessor, who had less than 1 year’s experience of this technique. MRI test: all made by one investigator and measured according to procedure Intra-tester reliability, ICC criterion validity, ANOVA Tomsich et al. (1996) Observational 27 (27 knees) 27 asymptomatic subjects; 7 males, 20 females; mean age 21 5.5 years Asymptomatic defined as no history of knee pathology Assessed by visual estimation and pluri-cal calliper, each subject in supine position, in 0 degrees tibiofemoral flexion, quadriceps relaxed, foot position to maintain leg in neutral rotation using a KT-100 foot stabilizer. (1) Visual estimation of medio-lateral position assessed by positioning the index fingers and thumbs on the sides of the femoral epicondyles and over the patellar midpoint. The distance between the index finger and thumb medially and laterally is an estimate. (2) Medio-lateral position assessed by callipers by positioning the callipers along both femoral epicondyles, the midpoint marker on the ruler of the pluri-cal callipers was placed over the patellar midpoint. The distance between the epicondyle to the patellar midpoint, medially and laterally, was then recorded Subjects assessed 3 times each, by the three different examiners. Assessors were blinded to subject’s identification Not assessed 3 physical therapists who spent a total of 2 h practicing the measurement procedure before the study. Therapist’s ages ranged from 25 to 27 with 2.5 to 5.5 years experience of orthopaedic practice, graduating from 3 different physiotherapy schools Intra- and inter-tester reliability, kappa, ICC and SEM Watson et al. (1999) Observational 56 (101 knees) 56 subjects; 22 males, 34 females; mean age 29 8.0, range 22–34 years 39 (76 knees) asymptomatic subjects mean age 28 6.2 17(25 knees) symptomatic subjects mean age 30 11.4 Asymptomatic defined as no knee pain or pathology Symptomatic defined as patellofemoral pain classified as patellofemoral joint pain reproducible following at least 2 of the following activities in the last month: ascending or descending stairs, prolonged sitting, squatting Subjects excluded if they had a history of knee surgery or patellar dislocation, or if there was evidence on clinical examination of knee ligamentus injury, meniscal injuries, patellar tendonopathy, major joint effusion or plica syndrome (continued on next page)
360
T.O. Smith et al. / Manual Therapy 14 (2009) 355–362
Table 1 (continued) Medial/lateral position test
Reliability assessment Validity assessment Tester details Statistical analysis
McConnell assessment: subject supine, tibiofemoral joint in full extension and femur parallel to the plinth, quadriceps relaxed through lower limb rotation not documented. Distance measured using a tape measure from the mid-patella to the medial femoral epicondyle and to the lateral femoral epicondyle. The midpoint was determined on visual estimation, and marked with a grease pencil. A score of 0 was allocated if the distance from the medial epicondyle to the mid-patella point was equal to the distance from the lateral epicondyle to mid-patella; 1 was allocated if the distance from the medial epicondyle to the mid-patella point was >0.5 cm from the lateral epicondyle to mid-patella Subjects assessed once, by 2 different examiners, on 2 separate occasions, 3–7 days after the initial measure. Assessors were blinded to whether subjects had knee pain Not assessed 2 senior physical therapy students who had received approximately 2 h of didactic instructions and 2 h of practice on the McConnell patellofemoral classification system of medio-lateral position Intra- and inter-tester reliability, kappa
ANOVA, analysis of variance; ICC, intra-class correlation coefficient; LPD, lateral patellar displacement; MACP, Manipulation Association of Chartered Physiotherapists; MRI, magnetic resonance imaging; SEM, standard error of the measurements.
(2006) and Herrington and Nester (2004) assessed the knee in 20 degrees flexion, whereas Powers et al. (1999), Tomsich et al. (1996), Fitzgerald and McClure (1995) and Watson et al. (1999) assessed the knee in full extension. Lower limb rotation was only documented as controlled in Tomsich et al.’s (1996) study in neutral. Only Watson et al. (1999), Tomsich et al. (1996), and Powers et al. (1999) acknowledged that the quadriceps muscles were relaxed during testing.
3.2. Reliability Intra-tester reliability of medio-lateral patellar position as assessed in seven studies. Six studies reported either substantial or near perfect agreement between assessment periods, with intraclass coefficient (ICC)/kappa results ranging from 0.70 to 0.99. Four studies all reported almost perfect agreement between test procedures in McEwen et al. (2007), Powers et al. (1999), Herrington et al. (2006), and Herrington and Nester’s (2004) results. Only Watson et al.’s (1999) study reported poor to fair agreement with 0.11–0.35 kappa results. Four studies assessed inter-tester reliability. These studies reported differing results. Two studies reported near perfect agreement in Herrington (2002) results with 0.91 and 0.94. In contrast, Tomsich et al. (1996), Fitzgerald and McClure (1995) and Watson et al. (1999) reporting poor agreement with results of 0.14, 0.10 and 0.02 respectively.
3.3. Criterion validity The criterion validity of assessment of medio-lateral patellar orientation was evaluated in studies by Herrington (2002), McEwan et al. (2007) and Powers et al. (1999). These studies reported variable agreement between clinical medio-lateral patellar position assessment and MRI evaluation. Herrington (2002) reported near perfect agreement between the measures with an ICC of 0.9. McEwan et al. (2007) reported substantial agreement with an ICC of 0.61, whilst Powers et al. (1999) reported moderate agreement with an ICC of 0.44. 3.4. Critical appraisal results The findings of the CASP appraisal are presented in Table 3. These suggest that the methodological quality of the papers was limited in a number of areas. The CASP review highlighted that all studies stated appropriate research questions and applied suitable study designs to answer their research questions. As Table 1 outlines, three studies used a references test (MRI) to assess the criterion validity of the medio-lateral patella position. Only McEwan et al. (2007) stated that assessors were blinded to the results of this test, whilst Herrington (2002) indicated that different assessors were used for their MRI and clinical findings. Population characteristics such as patient’s knee history and pathology, gender, age or weight and height were poorly described in five papers. Whilst all papers identified the basic method of assessing medio-lateral patellar
Table 2 Summary of results from studies included in this systematic review. Author (date)
Mean clinically assessed medio-lateral position in mm (SD)
Mean reference test medio-lateral position (SD)
Inter-tester reliability (ICC with SEM)
Intra-tester reliability (ICC with SEM)
Criterion validity ICC (p value)
Fitzgerald and McClure (1995) Herrington (2008)
N/D
N/A
0.10 (44%)a
N/A
N/A
PFPS group: lateral 7.5 (2.6); asymptomatic group: lateral 3.8 (2.4) Medial 8.98 (0.51); lateral 8.35 (0.66)
N/A
N/A
0.86, SEM 0.2 mm
N/A
LPD 5.0(2.8)
N/A
0.9
3 mm (6 mm) lateralised from central Medial females 2.5 (1.8)/males 2.3 (1.8); lateral females 6.6 (4.5)/males 5.9 (4.5) Medial 8.9 (0.1); lateral 8.3 (0.1) 6.8 9.6% lateral displacement as percentage of patella width
N/A
Medial measure 0.91; lateral measure 0.94 N/A
0.99 (p < 0.01), SEM 6 mm
N/A
N/A
N/A
0.99 (p < 0.015), SEM 0.1 mm
N/A
LPD 8.1 (2.8) 16.1 12.3% lateral displacement as percentage of patella width N/D N/A
N/A N/A
0.86 (0.1, CI 8.1–8.5) 0.91
0.61 (p ¼ 0.002) 0.44
0.14 (0.55) 0.02 (70%)a
0.70 (0.28) 0.11 (8.4) to 0.35 (0.74)a
N/A N/A
Herrington (2002)
Herrington et al. (2006) Herrington and Nester (2004) McEwan et al. (2007) Powers et al. (1999)
Tomsich et al. (1996) Watson et al. (1999)
N/D Frequency between testers of: score 0, 135–149; score 1, 47–53
ICC, intra-class correlation co-efficient; N/D, not documented; mm, millimetres; SD, standard deviation; N/A, not assessed; SEM, standard error of the measurements. a Kappa coefficient (percentage of agreement).
T.O. Smith et al. / Manual Therapy 14 (2009) 355–362
361
Table 3 A summary of the CASP results. CASP factors
Fitzgerald and McClure (1995)
Herrington Herrington Herrington (2008) (2002) et al. (2006)
Herrington and Nester (2004)
McEwan Powers Tomsich Watson et al. (2007) et al. (1999) et al. (1996) et al. (1999)
Clearly focused question stated Appropriate design Appropriate reference test available Did all receive reference and diagnostic test Could reference test findings influence diagnostic test result Population characteristics clearly defined Diagnostic test clearly defined Appropriate results analysis Precise statistical results presented Appropriate interpretation Ability to generalise results Were the results applicable to clinical practice
Y Y N
Y Y N
Y Y Y
Y Y N
Y Y N
Y Y Y
Y Y Y
Y Y N
Y Y N
N
N
Y
N
N
Y
Y
N
N
N/A
N/A
N
N/A
N/A
N
Y
N/A
N/A
N
Y
N
N
N
Y
Y
Y
Y
N Y N
N Y N
N Y N
N Y N
N Y N
N Y Y
N Y N
Y Y N
N Y N
Y Y Y
Y Y Y
Y N N
N N N
N N N
Y N N
Y Y Y
N N N
Y Y Y
Y, yes; N, no; N/A, not applicable.
position, all studies except Tomsich et al. (1996) did not clearly state either the position of the knee or lower limb, or whether the quadriceps were relaxed or contracted, confounding variables in assessing medio-lateral patellar position. The evidence-base used appropriate statistical tests with ICC and kappa analysis, but only McEwan et al. (2007) documented confidence intervals to assess the precision of their statistical findings. Since only Fitzgerald and McClure (1995), Powers et al. (1999), Watson et al. (1999) and Herrington (2008) recruited patients with patellofemoral pathology, only these studies were regarded as having any clinical significance to be generalisable to the clinic setting. 4. Discussion The findings of this review suggest that the intra-tester reliability of medio-lateral position tests is good, but that inter-tester reliability is variable. The criterion validity of these tests is at worst moderate. However, such conclusions should be interpreted with caution since the evidence-base presently exhibits a number of limitations. The two most important weaknesses identified were the poor documentation of the actual medio-lateral patella positioning test methods and the limited description of subject characteristics. Two distinct methods of assessing medio-lateral patellar position were recognised (Figs. 1 and 2). This review would suggest that Herrington’s (2002) methods appears to have better inter-tester reliability and criterion validity than McConnell’s (1986). This difference may account for the substantial difference in intra-tester results between the findings of Watson et al. (1999) and Herrington et al. (2006) and Herrington and Nester (2004), or inter-tester findings between Tomsich et al. (1996) and Herrington (2002). However, this cannot be categorically stated given the limited size of evidence presently available. Furthermore, with the exception of 12 subjects in Herrington’s (2008) study, all other studies which assessed Herrington’s (2002) method were undertaken on asymptomatic populations. As a result, it is not possible to generalise with confidence, these results to patients with patellofemoral disorders. Accordingly, a direct comparison of these two methods of assessing medio-lateral position is warranted to determine the optimal method of assessing patients with different patellofemoral disorders. A considerable weakness in the evidence-base is the poor description of the medio-lateral patellar position test. Studies did not demonstrate whether they controlled confounding factors such
as lower limb rotation, quadriceps contraction or knee flexion (McEwan et al., 2007; Herrington et al., 2006; Herrington, 2002, 2008; Herrington and Nester, 2004; Fitzgerald and McClure, 1995). These variables can influence the patellar position within the trochlear groove (Herrington and Pearson, 2008; Muhle et al., 1999). Variations in these factors between study methodologies may account for the differences in results between studies for intertester reliability. This should be considered when presenting the findings of similar studies in the future. The degree of knee flexion may be an important factor. Five papers (McEwan et al., 2007; Herrington et al., 2006; Herrington, 2002, 2008; Herrington and Nester 2004) assessed the knee in 20 degrees flexion, compared to full extension. Considering the patella engages with the femoral trochlear at approximately 10–30 degrees of knee flexion (Beasley and Vidal, 2004; Senavongse et al., 2003), it may be hypothesised that the good reliability results of these studies may be related to greater patellar osseous constraint compared to full extension. Further study may therefore be indicated to investigate this assumption assessing medio-lateral patellar position in full extension compared to difference ranges of tibiofemoral flexion. The papers reviewed poorly documented important subject characteristics, particularly in view of weight and height. Papers poorly distinguished between those subjects with patellar instability, patellofemoral pain syndrome or other patellofemoral disorders. Consequently, it was not possible to ascertain the heterogeneity of these papers. In response to this, it was deemed unstable to formally compare these paper’s results using a metaanalysis design. In addition, Egger et al. (2001) suggested that meta-analysis should not be undertaken for observational studies, which was the methodology design used in all the studies reviewed. It appeared that only Fitzgerald and McClure (1995) assessed medio-lateral patellar position in patients with subluxed patellar. The present evidence-base does not state whether the reliability or validity of this test is related to the severity of patellar displacement. Further study is recommended to investigate whether the accuracy of these measurements is related to the degree of patellar displacement in well-defined populations. With the exception of Herrington (2008), Herrington and Nester (2004) and Herrington et al. (2006), the assessors’ experience of the medial-lateral patellar position tests was well described. The assessors in each study appeared to have broadly similar levels of experience and training in each assessment method. However, it remains unclear whether the reliability or validity of the tests to
362
T.O. Smith et al. / Manual Therapy 14 (2009) 355–362
assess medio-lateral position is dependent on the method of teaching these measures. This may inform clinicians as to whether attendance at courses is warranted, or whether text and photographic teaching is sufficient to accurately assess this measurement. The results of this review would suggest that the intra-tester reliability of medio-lateral patellar orientation tests are satisfactory. Accordingly, clinicians can have some confidence that they have consistency in their measures between treatment sessions. It remains unclear whether the results of this measure are reproducible if patients change from one physiotherapist to another with such variable inter-tester reliability. Furthermore, further study is indicated to determine the clinical relevance of these findings. The reliability of physiotherapist’s abilities to translate their mediolateral displacement findings to specific taping placement to address abnormal patellar translation is presently unclear and should be addressed with future study. Although studies frequently described the age and gender of their subjects, only Fitzgerald and McClure (1995) and Herrington (2008) detailed the weight of their subjects to indicate body mass. Body mass may have influenced medio-lateral patellar position measurements. Fitzgerald and McClure (1995) acknowledged that it appeared more difficult to palpate the bony landmarks in those subjects with greater body mass. Accordingly, this may have contributed to variability in the measurement of these patients, and an additional variable which should be considered. 5. Conclusions The findings of this study indicate that the intra-tester reliability of medio-lateral patellar position tests are good, but that intertester reliability is variable. The criterion validity of these tests is at worse moderate. These are based on a limited evidence-base. Further study is recommended to compare the McConnell (1986) and Herrington (2002) methods of assessing medio-lateral patellar orientation. After this rigorous assessment, clinicians will then be better informed on the appropriateness of these tests when assessing patellar orientation in patients with patellofemoral disorders. Acknowledgements We thank the library staff at the Norfolk and Norwich University Hospital’s Sir Benjamin Gooch Library for their assistance in paper retrieval. We also thank Mr Mark Rowlands for his assistance with the photographs used in this paper. References Arendt EA, Fithian DC, Cohen E. Current concepts of lateral patella dislocation. Clinical Sports Medicine 2002;21:499–519. Beasley LS, Vidal AF. Traumatic patellar dislocation in children and adolescents: treatment update and literature review. Current Opinion in Paediatrics 2004;16:29–36. Critical Skills Appraisal Programme (CASP) Homepage on the Internet. Oxford, UK: Learning & Development Public Health Resource Unit; c. 2007. Available from: http://www.phru.nhs.uk/casp/critical_appraisal_tools.htm (accessed 1 May 2007). Crossley K, Bennell K, Green S, McConnell J. A systematic review of physical interventions for patellofemoral pain syndrome. Clinical Journal of Sports Medicine 2001;11(2):103–10.
Edwards A, Talbot R. The hard pressed researcher. A research handbook for the caring professions. London: Longman; 1994. Egger M, Davey Smith G, Schneider M. Systematic reviews of observational studies. In: Egger M, Davey Smith G, Altman DG, editors. Systematic reviews in health care. London: BMJ Books; 2001. p. 211–28. Evans R, Elwyn G, Edwards A. Review of instruments for peer assessment of physicians. BMJ 2004;328:1240. Fitzgerald GK, McClure PW. Reliability of measurements obtained with four tests for patellofemoral alignment. Physical Therapy 1995;75(2):84–92. Fulkerson JP, Shea KP. Disorders of patellofemoral alignment. Journal of Bone and Joint Surgery 1990;72-A:1424–9. Grelsamer RP, Newton PM, Staron RB. The medial-lateral position of the patella on routine magnetic resonance imaging: when is normal not normal? Arthroscopy 1998;14:23–8. Herrington LC. The inter-tester reliability of a clinical measurement used to determine the medial/lateral orientation of the patella. Manual Therapy 2002;7(3):163–7. Herrington L. The effect of corrective taping of the patella on patella position as defined by MRI. Research in Sports Medicine 2006;14:215–23. Herrington LC. The difference in a clinical measure of patella lateral position between individuals with patellofemoral pain and matched controls. Journal of Orthopaedic and Sports Physical Therapy 2008;38:59–62. Herrington L, Nester C. Q-angle undervalued? The relationship between Q-angel and medio-lateral position of the patella. Clinical Biomechanics 2004;19: 1070–3. Herrington L, Pearson S. The applicability of ultrasound imaging in the assessment of dynamic patella tracking: a preliminary investigation. The Knee 2008;15(2):125–7. Herrington L, Rivett N, Munro S. The relationship between patella position and length of the iliotibial band as assessed using Ober’s test. Manual Therapy 2006;11:182–6. Hughston JC. Subluxation of the patella. Journal of Bone and Joint Surgery 1968;50-A:1003–26. Insall J. Chondromalacia patellae: patellar malalignment syndrome. Orthopedic Clinics of North America 1979;10:117–27. McConnell J. The management of chondromalacia patellae: a long term solution. Australian Journal of Physiotherapy 1986;32(4):215–23. McConnell J. Rehabilitation and nonoperative treatment of patellar instability. Sports Medicine and Arthroscopy Reviews 2007;15:95–104. McEwan I, Herrington L, Thom J. The validity of clinical measures of patella position. Manual Therapy 2007;12:226–30. Mizuno Y, Kumagai M, Mattessich SM, Eilas JJ, Ramrattan N, Cosgarea AJ, et al. Q-angle influences tibiofemoral and patellofemoral kinematics. Journal of Orthopaedic Research 2001;19:834–40. Muhle C, Brossmann J, Heller M. Kinematic CT and MR imaging of the patellofemoral joint. European Radiology 1999;9(3):508–18. Ota S, Ward SR, Chen T-J, Tsai Y-J, Powers CM. Concurrent criterion-related validity and reliability of a clinical device used to assess lateral patellar displacement. Journal of Orthopaedic and Sports Physical Therapy 2006;36(9):645–52. Polgar S, Thomas SA. Introduction to research in the health sciences. 4th ed. London: Churchill Livingstone; 2000. Portney LG, Watkins MP. Foundations of clinical research. Applications to practice. 2nd ed. New Jersey: Prentice Hall; 2000. Powers CM, Mortenson S, Nishimoto D, Simon D. Criterion-related validity of a clinical measurement to determine the medial/lateral component of patellar orientation. Journal of Orthopaedic and Sports Physical Therapy 1999;29(7):372–7. Senavongse W, Farahmand F, Jones L, Andersen H, Bull AM, Amis AA. Quantitative measurement of patellofemoral joint stability: force-displacement behaviour of the human patella in vitro. Journal of Orthopaedic Research 2003;21:780–6. Sutlive TG, Mitchell SD, Maxfield SN, McLean CL, Neumann JC, Swiecki CR, et al. Identification of individuals with patellofemoral pain whose symptoms improved after a combined program of foot orthosis use and modified activity: a preliminary investigation. Physical Therapy 2004;84(1):49–61. Tolouei FM, Afshar A, Salarilak S, Sina A. CT patellar cortex tilt angle: a radiological method to measure patellar tilt. Iran Journal of Radiology 2005;3(1):17–21. Tomsich DA, Nitz AJ, Threlkeld AJ, Shapiro R. Patellofemoral alignment: reliability. Journal of Orthopaedic and Sports Physical Therapy 1996;23(3):200–8. Warden SJ, Hinman RS, Watson Jr MA, Avin KG, Bialocerkowski AE, Crossley KM. Patellar taping and bracing for the treatment of chronic knee pain: a systematic review and meta-analysis. Arthritis and Rheumatology 2008;15(1):73–83. Watson CJ, Propps M, Galt W, Redding A, Dobbs D. Reliability of McConnell’s classification of patellar orientation in symptomatic and asymptomatic subjects. Journal of Orthopaedic and Sports Physical Therapy 1999;29(7):378–85.