Clinical outcomes of rehabilitation for patients following lateral patellar dislocation: a systematic review

Physiotherapy 96 (2010) 269–281

Systematic review

Clinical outcomes of rehabilitation for patients following lateral patellar dislocation: a systematic review Toby O. Smith a,c,∗ , Leigh Davies b , Rachel Chester b,c , Allan Clark c , Simon T. Donell c a b

Institute of Orthopaedics, Norfolk and Norwich University Hospital, Norwich, UK Physiotherapy Department, Norfolk and Norwich University Hospital, Norwich, UK c Faculty of Health, University of East Anglia, Norwich, UK

Abstract Objectives Little has been published about which physiotherapy interventions are used to treat patients with instability of the patella. The purpose of this study was to review the literature systematically to determine the clinical outcomes of rehabilitation for patients following a lateral patellar dislocation. Data sources AMED, CINHAL, Cochrane Library, EMBASE, MEDLINE, PEDro and Scopus database searches were performed from their inception to August 2009. A search of unpublished and grey literature databases was undertaken, in addition to contacting all authors of included publications. Review methods All publications presenting the outcomes of patients following a conservatively managed lateral patellar dislocation were included. All eligible articles were appraised critically using the Critical Appraisal Skills Programme appraisal tool. Data on interventions, cohort characteristics, outcome measures and results were extracted. A narrative research synthesis method approach was adopted. Results In total, 29 publications were eligible for inclusion in this review. Although a proportion of patients experienced recurrent instability and dislocation episodes after rehabilitation, a large proportion of patients reported acceptable outcomes following physiotherapy. No randomised controlled clinical trials were identified assessing different physiotherapy interventions. The evidence base included a number of under-powered studies which poorly described the specific physiotherapy interventions prescribed. Conclusions Further, well-designed randomised controlled trials assessing different conservative management strategies with specific patient groups, to provide pre-intervention as well as follow-up data, are required to determine the optimal clinical outcomes of physiotherapy for patients following a lateral patellar dislocation. © 2010 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved. Keywords: Patellar dislocation; Physiotherapy; Rehabilitation; Conservative treatment; Systematic review

Introduction Patellar dislocation and associated recurrent instability is a complex musculoskeletal complaint. It commonly presents in young and physically active people [1,2]. Observational studies have estimated the incidence of patellar instability to be 43 per 100,000 [3], with a greater incidence in females than males [4]. Although not fully understood, the principal theory for a lateral patellar dislocation is based around the assump∗ Corresponding author at: Institute of Orthopaedics, Norfolk & Norwich University Hospital, Colney Lane, Norwich NR2 7UY, UK. Tel.: +44 01603 286990; fax: +44 01603 287369. E-mail address: [email protected] (T.O. Smith).

tion that the patella disengages from the trochlear groove due to poor osseous constraint from the lateral femoral condyle [5–8]; or because the lateral tissues, such as the lateral retinaculum and vastus lateralis, are able to overcome weaker medial structures, especially the medial patellofemoral ligament and the distal vastus medialis or vastus medialis obliquus (VMO). In the latter case, patellar stability is primarily dependent on a patient’s soft tissue ‘balance’ between the contractile and non-contractile medial and lateral structures. Historically, patients following a primary patellar dislocation have been managed conservatively. Such regimes have included a period of immobilisation and rest, followed by formal physiotherapy [8]. The aims of physiotherapy are to restore knee range of motion, and to strengthen the quadri-

0031-9406/$ – see front matter © 2010 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.physio.2010.02.006

270

T.O. Smith et al. / Physiotherapy 96 (2010) 269–281

ceps muscles with the aim of restoring soft tissue balance and patellar stability. However, recurrent patellar dislocation following a conservatively managed primary dislocation may occur in up to 44% of patients [9]. Recurrent patellar instability can have a considerable impact on a patient’s occupational and social pursuits, with a detrimental effect on their quality of life. In such cases, patients find it difficult to engage in sporting activities and strenuous tasks, since they are unable to trust that their knee will be able to cope with relatively normal tasks undertaken in everyday life. Although physiotherapy has been advocated for decades to patients following a lateral patellar dislocation [9,10], there remains little consensus about the optimal method of rehabilitating this patient group. Physiotherapists and orthopaedic surgeons have principally associated any rehabilitation programme with the prescription of quadriceps exercises. However, over the past 20 years, clinicians have suggested that the VMO should be preferentially strengthened to improve the patella’s medial contractile stability [11–13]. This is based on the premise that the vastus medialis is assumed to be ‘weaker’ or present with an abnormal onset timing compared with the vastus lateralis [14]. However, a previous systematic review indicated that it remains unclear whether the VMO can actually be preferentially targeted in patients following patellar dislocation, and there remains no evidence to demonstrate that a difference exists in onset timing between the vastus medialis and vastus lateralis in this patient group [14,15]. As a result, a considerable degree of confusion remains surrounding the optimal rehabilitation of patients following a patellar dislocation. Due to these uncertainties, the objective of this literature review was to determine the clinical outcomes following rehabilitation for patients following a lateral patellar dislocation.

Materials and methods Data source The following electronic databases were searched: AMED (1985 to August 2009), British Nursing Index (1985 to August 2009), CINHAL (1982 to August 2009), EMBASE (1974 to August 2009), MEDLINE (1950 to August 2009) and PsycINFO (1806 to August 2009) via Ovid. Scopus and the Cochrane Library were also searched. The MeSH terms and keywords with the Boolean operators adopted are presented in Table 1. Unpublished literature was also assessed using SIGLE (System for Information on Grey Literature in Europe), the National Technical Information Service, the National Research Register (UK) and Current Controlled Trials databases with the search term ‘patellar dislocation’. The reference list from each pertinent full-text manuscript was scrutinised for any omitted studies. Attempts were made to contact all corresponding authors for each included paper in order to identify any additional publications which had not been highlighted through the search strategy.

Table 1 Search strategy. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23.

patella/ dislocations/ 1 OR 2 physical therapy (specialty)/ rehabilitation/ physiotherapy.tw. brac$.tw. immobili$.tw. splint$.tw. exercis$.tw. manual therapy.tw. mobilisation.tw. mobilization.tw. tape.tw. taping.tw. electrotherap$.tw. biofeedback.tw. ultrasound.tw. muscle stimulation.tw. electronic stimulation.tw. OR/4 – 20 3 AND 21 limit 22 to humans

Eligibility criteria This review included all full-text, randomised and non-randomised clinical trials and observational studies, published in any language, which presented the outcomes of patients who were conservatively managed following a lateral patellar dislocation. Publications assessing patients who reported primary patellar dislocation and recurrent dislocations were included. Papers where subjects presented with patellofemoral pain syndrome, patellar subluxation or generalised patellar instability symptoms, and did not report a convincing patellar dislocation, were excluded. In addition, where it was not possible to differentiate between clinical results following conservative compared with surgical procedures, papers were excluded. Finally, editorials, comments and letters, and cadaver and animal studies were also excluded. Study identification Two reviewers (TS, LD) independently reviewed all titles and abstracts that were identified from the search strategy. Full-text manuscripts for all potentially eligible studies were ordered. These were independently reviewed by each of the reviewers a second time in respect of the predefined eligibility criteria. Data extraction Data extraction for each eligible paper was performed independently by two reviewers (TS, LD) using a predefined spreadsheet. The reviewers’ spreadsheets were amalgamated to create an agreed extraction form. Data extracted included:

T.O. Smith et al. / Physiotherapy 96 (2010) 269–281

study design, sample size, duration from dislocation to rehabilitation, treatment strategies, clinical outcomes (recurrent dislocation, recurrent instability, functional outcomes, pain, range of motion, strength, apprehension, maltracking) and the follow-up period. In cases where insufficient data were provided within the publication, attempts were made to contact all corresponding authors to identify such data. Critical appraisal Each reviewer (TS, LD) appraised the included studies critically using the Critical Appraisal Skills Programme (CASP) critical appraisal tool [16]. The CASP tool is comprised of three appraisal sections: an assessment of study validity, an evaluation of methodological quality and presentation of results, and an assessment of external validity. If any disagreements arose regarding study selection, data extraction or appraisal score, these were resolved through discussion between the two reviewers. If agreement could not be reached, this would have been resolved through a third reviewer (RC). However, this was not required in this study.

Fig. 1. PRISMA flow chart.

271

Data analysis All analyses were initially undertaken by one reviewer (TS) and verified by another reviewer (LD). A narrative review was undertaken of all included literature. An assessment of the efficacy of different physiotherapy treatments through a meta-analysis was planned. However, it was not possible to conduct such an analysis since there was considerable methodological heterogeneity, particularly with the information provided about treatment intervention, whilst no studies had compared two different rehabilitation or physiotherapy strategies. Accordingly, there were insufficient data to conduct a meta-analysis.

Results Search strategy The results of the search strategy are presented in a PRISMA flow chart (Fig. 1) [17]. As Fig. 1 demonstrates, a total of 254 citations were identified through the search strategy. Twenty-nine papers satisfied the eligibility criteria and were therefore included in the review. This included 15

272

Table 2 Summary of the studies reviewed. Study

Numbers Patients

Knees

Gender (male/female)

Diagnosis and how made

Mean duration prior to commencing rehabilitation

Mean follow-up period (range)

Two or more complete patellar dislocations Convincing history of primary patellar dislocation with haematosis/effusion; medial retinaculum tenderness; positive apprehension test Reported recurrent patellar dislocation Reported primary patellar dislocation; knee effusion; positive apprehension test; tenderness on medial retinaculum Primary patellar dislocation requiring manipulation for reduction Presented as a primary patellar dislocation to the hospital Locked dislocation of history of knee trauma, intra-articular haematoma, tenderness of the medial epicondyle and positive apprehension test Convincing history of patellar dislocation Positive apprehension test Evident or suspected patellar dislocation Convincing history of patellar dislocation on magnetic resonance imaging. Positive apprehension test N/S N/S Convincing history of patellar dislocation Convincing history of primary patellar dislocation with positive clinical diagnosis on evaluation N/S N/S Reported recurrent patellar dislocation Patellar dislocation on examination with convincing history and signs of patellar dislocation Observed locked primary patellar dislocation or dislocatable on examination under anaesthetic Unreduced patellar dislocation reported or observed in clinic Convincing history of patellar dislocation Clinically evident or suspected patellar dislocation Primary patellar dislocation with convincing history and clinical signs Reported primary patellar dislocation Primary patellar dislocation with convincing history and presentation Reported or observed traumatic primary patellar dislocation Primary patellar dislocation confirmed by physical examination and magnetic resonance imaging Reported primary patellar dislocation and evidence of physical examination

N/S <4 weeks

14 years (11 to 19 years) 24 weeks

21 years N/S

6 weeks 8.2 years (2 to 15 years)

3 to 4 weeks

36.3 months

14 days

2 years (minimum)

N/S

2 years

N/S 0 Approximately 4 to 5 days 4 weeks

5 years (minimum) 2 years (minimum) 40 months (6 to 174 months) 12 weeks

N/S N/S N/S N/S

31 months (15 to 64 months) 1 year 5.9 years (1 to 31 years) 13 years (6 to 26 years)

N/S N/S N/S N/S

13 years (SD 5 years) 11 years (6 to 24 years) 30 years (20 to 45 years) 31 months (6 to 61 months)

<14 days

7.2 years (5.7 to 9.1 years)

≤14 days

25 months (20 to 45 months)

3 days <2 weeks N/S

5 weeks 14 years (11 to 15 years) 35 months (17 to 54 months)

10 days N/S

9 weeks 3 years (11 months to 6 years)

1 day (0 to 7 days)

7 years (6 to 9 years)

<21 days

6.9 years (4 to 10 years)

Day 1

7.5 years (6 to 11 years)

Arnbjörnsson et al. [26] Atkins et al. [50]

29 74

29 74

25 (13 to 54) 19.9 (11 to 56)

7/22 37/37

Bohannon [22] Buchner et al. [1]

1 63

1 63

29 21.1 (10 to 52)

1/0 35/28

Camanho et al. [34]

16

16

26.8 (12 to 74)

7/9

Cash and Hughston [10]

100

103

N/S

N/S

Christiansen et al. [35]

35

35

19.9 (13 to 39)

18/17

Cofield and Bryan [9] Garth et al. [54] Hawkins et al. [27] Helgeson and Smith [44]

45 68 20 1

48 79 20 1

17.6 (10 to 54) 16.4 (7 to 35) 19 (13 to 39) 23

19/26 49/18 11/9 0/1

Hvass et al. [46] Kiviluoto et al. [2] Larsen and Lauridsen [40] Mäenpää and Lehto [30]

37 77 71 100

37 77 79 100

18 (8 to 32) 23 18.7 (6 to 52) 23 (10 to 64)

15/22 29/48 27/44 37/63

Mäenpää et al. [49] Mäenpää et al. [18] Marcacci et al. [19] McManus et al. [21]

82 75 16 33

82 75 16 33

36 (11) N/S N/S N/S

32/50 N/S 6/10 N/S

Nikku et al. [25]

57

57

20 (8)

27/30

Nikku et al. [37]

55

55

19.1 (7.5)

25/30

Osterhues [23] Palmu et al. [29] Pedersen and Pedersen [48]

1 28 26

1 28 26

49 13 (2) 22 (11 to 74)

0/1 9/19 16/8

Racouillat [24] Savarese and Lunghi [20]

1 17

1 17

16 N/S

0/1 N/S

Sillanpää et al. [32]

22

22

20.0 (19 to 21)

21/2

Sillanpää et al. [33]

53

53

20.0 (19 to 23)

53/0

Sillanpää et al. [31]

76

76

20.0 (19 to 22)

72/4

SD, standard deviation; N/S, not stated.

T.O. Smith et al. / Physiotherapy 96 (2010) 269–281

Mean age (years) SD (range)

Table 3 Summary of the Critical Appraisal Skills Programme results.

Total

Study design Focused question Appropriate design Population defined Recruitment methods acknowledged Sample size defined by power Study setting described Interventions described Physiotherapy treatment reproducible Outcome measures defined Observers defined Statistical methods described Variance described Inferential statistics employed Confidence intervals presented Appropriate interpretation Generalisability Relevance to present evidence base Clinical relevance discussed Total

Atkins et al. [50] Obs Yes Yes Yes Yes

Bohannon [22] CS Yes Yes Yes No

Buchner et al. [1] Retro No Yes No No

Camanho et al. [34] Obs Yes Yes Yes No

Cash and Hughston [10] Retro No Yes Yes No

Christiansen et al. [35] RCT Yes Yes No No

Cofield and Bryan [9] Obs Yes Yes No No

Garth et al. [54] Obs Yes Yes Yes No

Hawkins et al. [27] Obs No Yes Yes No

Hvass et al. [46] Obs No Yes Yes No

Helgeson and Smith [44] CS Yes Yes Yes No

Larsen and Lauridsen [40] Obs No Yes No No

Kiviluoto et al. [2] Obs Yes Yes No No

Mäenpää et al. [49] Obs No Yes No No

No No No No

Yes Yes Yes No

No No Yes Yes

No Yes No No

No Yes No No

No Yes Yes No

Yes Yes Yes No

No Yes No No

No No Yes Yes

No No No No

No No No No

No No Yes Yes

No Yes Yes No

No Yes Yes No

No No No No

Yes No Yes Yes Yes No

Yes No Yes Yes Yes No

Yes No No No No No

Yes No Yes Yes Yes No

Yes No Yes No Yes No

Yes No Yes No No No

Yes No Yes Yes Yes No

Yes No No No No No

Yes No Yes No Yes No

Yes No No No No No

No No No No Yes No

Yes No No No No No

Yes No Yes No Yes No

Yes No Yes No Yes No

Yes No Yes Yes Yes No

Yes No Yes

Yes Yes Yes

Yes Yes Yes

Yes No Yes

Yes Yes Yes

Yes Yes Yes

Yes No Yes

Yes No Yes

Yes Yes Yes

Yes Yes Yes

Yes No No

Yes Yes No

Yes No Yes

Yes No Yes

Yes No Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

9

15

10

9

11

10

12

7

12

7

5

9

9

10

8

Mäenpää et al. [18] Obs No Yes No No

Mäenpää and Lehto [30] Obs Yes Yes No No

Marcacci et al. [19] CC No Yes No No

McManus et al. [21] Obs No No Yes Yes

Nikku et al. [25] RCT No Yes Yes No

Nikku et al. [37] RCT No Yes Yes Yes

Osterhues [23] CS No Yes Yes No

Palmu et al. [29] RCT Yes Yes Yes No

Pedersen and Pedersen [48] Obs Yes Yes No Yes

Racouillat [24] CS Yes Yes Yes No

Savarese and Lunghi [20] Obs Yes Yes No No

Sillanpää et al. [32] RCT Yes Yes Yes No

Sillanpää et al. [33] RCT Yes Yes Yes Yes

Sillanpää et al. [31] Obs Yes Yes Yes No

No No No No

No Yes Yes No

No Yes No No

No Yes Yes No

No Yes Yes No

No Yes Yes No

No No Yes Yes

Yes Yes Yes No

No Yes Yes No

No No Yes Yes

No No Yes No

Yes Yes Yes No

No Yes No No

No Yes Yes No

Yes No Yes Yes Yes No

Yes No Yes Yes Yes No

Yes No No No No No

Yes No No No No No

Yes No Yes Yes Yes Yes

Yes No Yes Yes Yes Yes

Yes No No No No No

Yes Yes Yes Yes Yes No

Yes No Yes Yes Yes No

Yes No No No No No

Yes No No No No No

Yes Yes Yes Yes Yes No

Yes No Yes Yes Yes No

Yes Yes Yes Yes Yes No

Yes No Yes

Yes No Yes

Yes No Yes

No Yes Yes

Yes Yes Yes

Yes Yes Yes

Yes No Yes

Yes Yes Yes

Yes Yes Yes

Yes Yes Yes

Yes Yes Yes

Yes Yes Yes

Yes Yes Yes

Yes Yes Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

8

11

6

8

13

14

8

15

13

10

8

15

13

14

T.O. Smith et al. / Physiotherapy 96 (2010) 269–281

Study design Focused question Appropriate design Population defined Recruitment methods acknowledged Sample size defined by power Study setting described Interventions described Physiotherapy treatment reproducible Outcome measures defined Observers defined Statistical methods described Variance described Inferential statistics employed Confidence intervals presented Appropriate interpretation Generalisability Relevance to present evidence base Clinical relevance discussed

Arnbjörnsson et al. [26] CC Yes Yes No No

CC, case–control study; Obs, observational (prospective) study; CS, case study; Retro, retrospective study; RCT, randomised controlled trial. 273

274

T.O. Smith et al. / Physiotherapy 96 (2010) 269–281

prospective observational studies, six randomised controlled trials of operative compared with non-operative management, four case studies, two case–controlled studies and two retrospective studies. These are summarised in Table 2. Critical appraisal The findings of the critical appraisal are summarised in Table 3. On analysis, the literature presented with a number of methodological limitations. Twelve studies did not define their populations clearly in terms of diagnosis, duration since injury or past musculoskeletal history. Only four studies identified how subjects were recruited, whilst only four papers justified their sample sizes based on power calculations. Eighteen papers clearly described the interventions undertaken. Whilst the general management strategies undertaken were clearly described in these papers, only five publications presented sufficient information to reproduce their methodologies for physiotherapy treatments. Furthermore, whilst all studies reviewed used appropriate outcome measures to evaluate their cohorts, only three studies detailed the number or types of assessors employed. No studies blinded their assessors or patients to the treatments prescribed. Whilst inferential statistics were presented in 19 publications, confidence intervals were only provided in two papers. However, all authors interpreted their findings appropriately and related these results suitably to clinical practice and the existing evidence base. Population characteristics The population characteristics of patients included in the review are summarised in Table 2, whilst Table 3 summarises the rehabilitation strategies adopted in each paper. A total of 1210 patients and 1218 knees were included. Mean reported patient age was 21.4 years [standard deviation (SD) 7.2]. In five papers, the average age was not detailed [10,18–21]. Four hundred and ninety-three males and 490 females were recruited within 25 studies. Patient numbers were not documented in four studies [10,18,20,21]. The most commonly used criterion to diagnose the occurrence of a lateral patellar dislocation was the patient’s ability to provide a convincing report of a patellar dislocation, such as visualisation of the dislocated patella and then, in some cases, its spontaneous reduction or the necessity for its manual reduction. This was applied in 15 studies. In addition, a positive apprehension test and tenderness on medial retinaculum palpation were also used in the diagnosis of five and three cohorts, respectively. Nine studies diagnosed a lateral patellar dislocation through the requirement of the patella being reduced under anaesthesia or through radiological evidence of a locked patella. Three studies did not state what criteria were used to identify their sample of patients following patellar dislocation. Twenty-two studies described that their cohorts were primary patellar dislocations, whereas two studies described that their cohorts had sustained recur-

rent dislocations. The remaining five studies did not state whether their patients had experienced a primary or recurrent dislocation (Table 4 ). The mean duration from primary dislocation to intervention was 7.6 days (SD 9.5), stated in seven studies. Three studies reported that rehabilitation began within 14 days of the primary patellar dislocation, one reported that rehabilitation commenced less than 28 days after injury, and one study stated that the reported rehabilitation programme began 21 years since the patient’s primary dislocation [21]. The mean follow-up duration of the reviewed cohorts was 6.1 years (SD 6.8), ranging from 5 weeks [22] to 45 years [18]. Clinical outcomes A variety of different clinical outcomes have been reported in patients following physiotherapy management after a lateral patellar dislocation. These will be assessed individually below. Functional assessment A number of different assessment methods were used to determine the functional outcomes of patients following rehabilitation of a patellar dislocation. These methods included the Kujala score [28], assessed in nine studies [17,25,29–35]; the Lysholm knee score [36], assessed in three studies [1,26,37]; the Hughston visual analogue scale knee score [38], assessed in three studies [25,29,37]; and the Tegner level of activity score [39], assessed in six studies [1,25,29,31,33,37]. In addition, two studies [19,40] presented their functional outcomes using the Crosby and Insall assessment tool [41,42], one study assessed their cohort with the Lower Extremity Functional Scale [43,44], Savarese and Lunghi [20] assessed the functional outcomes of their cohort using the Hall assessment [45], and Hvass et al. [46] assessed outcomes using the Cox rating system. Although they did not state the specific tool used, Christiansen et al. [35] assessed patellar instability using a patellar instability score, in addition to using the Knee Injury and Osteoarthritis Scores [47]. The results of these tests indicated that, after a patellar dislocation, patients regain acceptable to excellent function following rehabilitation. There was no substantial difference in the individual outcomes between the studies. Only the result of the Tegner activity score presented a difference between studies. For this outcome measure, patients reported a mean post-rehabilitation Tegner score of 6.2, ranging from 4.6 [1] to 6 [29]. Two studies reported a decrease in activity level after dislocation by 0.7 [37] and 2.2 [1], whilst one study reported an increase in Tegner score after physiotherapy by 1 point [29]. Whilst there was no substantial difference in the treatment strategies adopted between the groups, as acknowledged earlier, this may be attributed to a difference between the cohorts, where Palmu et al.’s [29] sample consisted solely of young patients, whilst Nikku et al.’s [37] and Buchner et al.’s [1] studies included adult patients.

T.O. Smith et al. / Physiotherapy 96 (2010) 269–281 Table 4 Conservative treatment strategies used.

275

276 Table 4 (Continued )

T.O. Smith et al. / Physiotherapy 96 (2010) 269–281

T.O. Smith et al. / Physiotherapy 96 (2010) 269–281

277

Fig. 3. Frequency of recurrent instability (not dislocation) symptoms after rehabilitation.

Fig. 2. Frequency of recurrent patellar dislocation after rehabilitation.

Recurrent dislocation and instability Twenty-two studies assessed the frequency of recurrent patellar dislocation. These indicated that 33% (range 6% to 100%) of patients reported repeated patellar dislocation after rehabilitation. As Fig. 2 demonstrates, two studies presented with a considerably higher percentage of recurrent dislocation than the other studies [22,29]. Bohannon’s [22] study was a short follow-up, single case study assessing the treatment effects of electronic stimulation alone. Palmu et al.’s [29] study was the only research which solely recruited people under 16 years of age. A recurrent dislocation rate of less than 10% was reported in one study [21]. In this paper, only two cases (6%) experienced recurrent patellar dislocation. The treatment strategies used in this study (a period of immobilisation followed by quadriceps strengthening exercises) were comparable to those documented by all eight studies which reported a recurrent dislocation rate of less than 20% [20,29–32,37,48]. Twelve papers presented data assessing the frequency of instability or subluxation symptoms in the absence of frank dislocation events after an initial lateral patellar dislocation. These reported that 27% (range 15% to 70%) of cohorts reported recurrent instability following rehabilitation. As Fig. 3 demonstrates, this trend was consistent between the studies, with the exception of Nikku et al.’s [25] findings which reported that 70% of their cohort presented with recurrent patellar instability following rehabilitation. Unfortunately, Nikku et al. [25] did not state what treatments were included in their rehabilitation programme to assess whether this difference in recurrent instability or subluxation was attributable to the interventions provided. Furthermore, this study’s follow-up period was considerable longer (mean 7.2 years) compared with others reviewed [20,21,34,46,48], which may have contributed to this higher recurrent instability rate (Fig. 4).

Pain Five studies assessed knee pain at 2.5 to 3 years following rehabilitation [20,27,46,48]; one study assessed knee pain at 8 years follow-up [1]. All studies reported that pain remained in a proportion of their cohort on follow-up. There was considerable variation in the method of assessing this outcome. Hawkins et al. [27] stated that five patients (25%) reported mild pain, six patients (30%) reported moderate pain and four patients (20%) reported severe pain. Pedersen and Pedersen [48] stated that nine subjects (35%) reported pain at rest. Savarese and Lunghi [20] indicated that seven patients (41%) reported pain, whilst Hvass et al. [46] stated that eight patients (22%) reported pain. Buchner et al. [1] assessed pain using a visual analogue scale with a mean follow-up period of 8 years. They reported a mean score of 3 in their cohort at this longer-term measure. Due to the variation in the methodology of assessing pain between these studies, it was not possible to gain a consensus about whether the different interventions used in managing this patient group substantially influenced perceived pain.

Fig. 4. Need for surgical intervention after rehabilitation.

278

T.O. Smith et al. / Physiotherapy 96 (2010) 269–281

Range of knee motion Knee range of motion was assessed through a variety of different methods in eight studies [20,23,29,30,32,44,49,50]. There was some variation in the reported results. Osterhues [23] reported that knee range of motion was equal between the dislocated and contralateral limb at 5 weeks, whilst Helgeson and Smith [44] reported that full range of motion was obtained following 12 weeks of rehabilitation. Whilst not stating the extent, Savarese and Lunghi [20] reported that knee range of motion was limited in 12% of cases at final follow-up. When analysing the treatment strategies adopted, Osterhues [23], Helgeson and Smith [44] and Atkins et al. [50] incorporated range of motion exercises into their rehabilitation programmes, whereas Savarese and Lunghi [20], Palmu et al. [29], Mäenpää and Lehto [30] and Sillanpää et al. [32] solely prescribed muscle strengthening exercises. This may have accounted for this difference in outcome. Using a more objective description of range of motion, Sillanpää et al. [32] assessed total range of motion. They reported a mean range of 140 degrees, ranging from 130 to 150 degrees. Atkins et al. [50] presented extension and flexion range of motion values in their observational cohort study. They reported a mean extension of 0 degrees (−5 to 5 degrees), whilst flexion was measured as 132 degrees ranging from 75 to 155 degrees. Mäenpää et al. [49] and Mäenpää and Lehto [30] reported that a flexion deficit was evident in 23% and 21% of their cohorts, respectively. An extension deficit was also exhibited in 15% and 13% of patients in these studies [30,49]. Since there was limited information on the rehabilitation protocols of Mäenpää et al.’s [49] and Mäenpää and Lehto’s [30] studies, it was not possible to determine whether the difference between these studies and those of Atkins et al. [50] and Sillanpää et al. [32] were associated with the interventions prescribed. Muscle strength and power Muscle strength and power was assessed through the Medical Research Council’s (MRC) muscle rating system, isokinetic strength and observational assessment. All studies suggested that after rehabilitation, muscle strength remained reduced in a proportion of patients. One study assessed muscle strength using the MRC observational grading system [51]. This case report showed an improvement in quadriceps strength from 2+/5 to 4+/5 over a 9-week period [24]. Three studies presented the results of isokinetic lower limb strength and power following rehabilitation [18,49,50]. Atkins et al. [50] reported that isokinetic knee extension torque was greater than 80% of the contralateral limb in 60 out of 74 patients by 24 weeks. Mäenpää et al. [18] demonstrated that there was a 10% deficit in quadriceps muscle testing at a mean of 11 years follow-up when assessed at 60 degrees knee range, whereas there was no significant deficit at full extension. Although Mäenpää et al. [49] did not comment on isokinetic deficit following a rehabilitation programme, they reported that at final follow-up, there was a significant

difference in quadriceps torque, with less torque measured in recurrent compared with non-recurrent dislocation patients, but no significant difference in hamstring torque between these groups (P < 0.05) [49]. On comparing these results, as Table 2 demonstrates, only Atkins et al. [50] presented details on which physiotherapy interventions and exercises were taught to these patients, whilst Mäenpää et al. [18,49] neglected to provide this important information. Three studies evaluated quadriceps atrophy [20,23,27]. Osterhues [23] reported minimal quadriceps atrophy in their single case study at final (5 weeks) follow-up. However, Hawkins et al. [27] reported that 20% of patients presented with observable quadriceps atrophy at a mean 40 months follow-up, and Savarese and Lunghi [20] reported that 76% of patients exhibited quadriceps atrophy at 3 years. The difference in outcomes may be attributed to the structured exercises prescribed to Osterhues’s [23] case, whilst Hawkins et al.’s [27] patients did not receive physiotherapy exercises as part of their intervention. Furthermore, Savarese and Lunghi’s [20] cohort, who presented with a high incidence of quadriceps atrophy, were prescribed isometric quadriceps exercises. Since these exercises have been shown to have a limited effect on muscle hypertrophy [52], this may have accounted for these findings. Apprehension The apprehension test was assessed in five studies after rehabilitation [20,21,27,37,40]. A positive apprehension test was recorded in a mean of 47.9% (SD 19.5) of these cohorts, ranging from 29% [37] to 82% [21]. Whilst there was a considerable range in apprehension test results, the treatment strategies were broadly similar between the studies, consisting of immobilisation followed by various forms of quadriceps exercises. The only exception was Hawkins et al.’s [27] study, where patients did not receive any exercises; this study reported a positive apprehension test in 10 patients (50%). Maltracking Patellar maltracking was assessed clinically in two studies after rehabilitation [27,50]. Hawkins et al. [27] reported that eight out of 20 patients still presented with maltracking on review at 40 months. Conversely, only 12 patients in Atkins et al.’s [50] cohort of 74 patients presented with lateral patellar tracking at an earlier 12-week review. This difference in maltracking may be related to the interventions prescribed, since subjects in Hawkins et al.’s [27] study were solely immobilised and did not receive exercises, whereas Atkins et al. [50] prescribed passive and closed chain strengthening exercises to their cohort.

Discussion This study has identified that although recurrent instability and dislocation appeared to continue for a number of patients, a large proportion of cohorts have reported accept-

T.O. Smith et al. / Physiotherapy 96 (2010) 269–281

able outcomes following rehabilitation. It was not possible to determine the efficacy of different physiotherapy treatments used for patients following a lateral patellar dislocation, since no studies used a control group or compared two or more physiotherapy interventions using well-designed randomised controlled trials. This review identified that the methodological quality of the present evidence base exhibits a number of limitations. The most pressing was that the efficacy of different physiotherapy treatments used in the management of patients following patellar dislocation cannot be determined, since no randomised controlled trials have been conducted. Without this, it is not possible to determine treatment efficacy. Similarly, the cohort and rehabilitation programmes were heterogeneous between studies. Therefore, it is not possible to state whether outcomes should be attributed to a specific modality, or whether any differences were a consequence of population variance. In general, the papers poorly described the physiotherapy interventions utilised. For instance, the specific positioning, frequency, duration or progression of exercise programmes was only detailed sufficiently in two papers [23,24], thereby limiting clinical interpretation. In addition, sample sizes were not based on power calculations. Accordingly, the samples recruited may not necessarily have been large enough to detect a difference in outcome following a rehabilitation programme, irrespective of whether or not a difference existed [53]. The method of recruitment of patients was not clearly stated. It was therefore unclear whether allocation bias impacted on findings or whether some patients were excluded from presented series due to poor outcomes. The papers poorly described who assessed the subjects. Accordingly, it was not possible to determine whether measurement error influenced the results obtained, or whether the experiences or training of the assessors was a variable which may have accounted for any between-study differences. Finally, pre-physiotherapy baseline data were only presented for Tegner scores in three studies. Consequently, it was not possible to determine the effect of physiotherapy on each patient’s recovery for all other outcome measures. These limitations should be considered when designing future longitudinal cohort studies and randomised controlled trials. There is considerable variation in clinical presentation and anatomical abnormalities within the patellar dislocation population [29,31,37]. For example, patients can be hypermobile, exhibit trochlear dysplasia, patella alta, rupture of the medial patellofemoral joint, or various proximal or distal biomechanical variances such as poor glutei muscle control or femoral, tibial or forefoot rotational abnormalities. Studies have not categorised patients by their principal anatomical presentation (e.g. osseous, soft tissue or biomechanical abnormality) to differentiate their aetiological features. The ability to define the patient population under study would produce greater external validity for clinicians and improve generalisability. This is of considerable importance since such anatomical abnormalities are considered prognostic indicators [18,30,50,54]. This should be considered further when

279

reviewing literature, and when adopting such findings into clinical practice. The literature poorly differentiated between the assessment of recurrent and primary patellar dislocation. As well as potentially presenting with anatomical differences [18,30], patients who sustain recurrent patellar dislocations frequently receive physiotherapy a number of times over a period of years as this is considered the mainstay treatment following a patellar dislocation [8,55]. Attitudes to physiotherapy may differ between patients who experience a single isolated patellar dislocation and patients who have suffered recurrent dislocations. It is suggested that health beliefs and patient–physiotherapist interactions may be an important variable, despite being complex, which could be associated with differences in outcomes between primary and recurrent patellar dislocation rehabilitation. There was considerable between-study variability for the initial management of patients following a patellar dislocation. As Table 2 demonstrates, the methods for immobilisation varied widely between studies, from no immobilisation to immobilisation using a cylinder cast. Furthermore, the duration of immobilisation also varied from 0 days [54] to 6 weeks [9,31]. Whilst it remains unclear whether the type of immobilisation influences outcomes, Mäenpää et al. [49] suggested that the duration of immobilisation had a substantial effect on outcome, citing that immobilisation causes atrophy of type I and type II muscle fibres, in addition to degenerative changes of bone, cartilage and ligaments [30,49,56,57]. It is therefore recommended that the efficacy of immobilisation and its potential impact on physiotherapy rehabilitation should be considered and standardised when designing future research, to prevent these factors acting as confounding variables. Although used in two studies [34,54], the literature did not indicate overall that specific VMO exercises are widely used in practice. Neither of these studies stated the outcome of VMO exercises on muscle power, recurrent dislocation or instability. This is important given that there remains particular controversy over the prescription of specific VMO exercises in this patient group. Previous authors have suggested that an abnormality in VMO onset timing or activity may be an aetiological factor in the development of patellar dislocation and instability symptoms [11,12,58,59]. Nonetheless, it still remains uncertain whether there is a difference in VMO onset timing or activity in patients following patellar dislocation [15], or whether the VMO can be preferentially strengthened in this patient group [14]. However, textbook and academic papers have widely suggested that VMO exercises should be included in the rehabilitation of patients following patellar dislocation [6,13,60].

Conclusions This review indicated that a variety of different physiotherapy strategies have been reported for the rehabilitation

280

T.O. Smith et al. / Physiotherapy 96 (2010) 269–281

of patients following lateral patellar dislocation. The optimal strategy is not yet known. Accordingly, a well-designed randomised controlled trial is required to determine how best to manage patients following a lateral patellar dislocation to improve the management of this complex musculoskeletal condition.

Acknowledgements The authors wish to thank the library staff at the Norfolk and Norwich University Hospital’s Sir Thomas Browne Library for their assistance in gathering the papers required for this study. Ethical approval: None required. Funding: This study forms part of a PhD undertaken at the University of East Anglia by Toby Smith, which has been partly funded by Action Arthritis. Conflict of interest: None declared.

References [1] Buchner M, Baudendistel B, Sabo D, Schmitt H. Acute traumatic primary patellar dislocation. Long-term results comparing conservative and surgical treatment. Clin J Sport Med 2005;15:62–6. [2] Kiviluoto O, Pasila M, Santavirta S, Sundholm A, Hämäläinen M. Recurrences after conservative treatment of acute dislocation of the patella. Ital J Sports Trauma 1986;3:159–62. [3] Nietosvaara Y. The femoral sulcus in children: an ultrasonographic study. J Bone Joint Surg 1994;76-B:807–9. [4] Fithian DC, Paxton EW, Stone ML, Silvia P, Davis DK, Elias DA, et al. Epidemiology and natural history of acute patellar dislocation. Am J Sport Med 2004;32:1114–21. [5] Aglietti P, Givin F, Cuomo P. Disorders of the patellofemoral join. In: Scott WN, editor. Insall and Scott surgery of the knee. 4th ed. London: Churchill Livingstone Elsevier; 2006. p. 807–985. [6] Scudero GR, McCann PD. Sports medicine. A comprehensive approach. 2nd ed. Philadelphia: Elsevier Mosby; 2005. [7] Donell S. Patellofemoral dysfunction–extensor mechanisms malalignment. Curr Orthop 2006;20:103–11. [8] Grelsamer RP. Current concept review. Patellar malalignment. J Bone Joint Surg 2000;82–A:1639–50. [9] Cofield RH, Bryan RS. Acute dislocation of the patella: results of conservative treatment. J Trauma 1977;17:526–31. [10] Cash JD, Hughston JC. Treatment of acute patellar dislocation. Am J Sport Med 1988;16:244–9. [11] McConnell J. The physical therapist’s approach to patellofemoral disorders. Clin J Sport Med 2002;21:363–87. [12] Sperner G, Benedetto KP, Glotzer W. Pathology, diagnosis and therapy of patellar dislocation. Sportverletz Sportschad 1990;4:69–72. [13] Solomon L, Warwick DJ, Nayagam S. Apley’s system of orthopaedics and fractures. 8th ed. London: Arnold; 2001. [14] Smith TO, Bowyer D, Dixon J, Stephenson R, Chester R, Donell ST. Can vastus medialis oblique be preferentially activated? A systematic review of electromyographic studies. Physiother Theory Pract 2009;25:69–98. [15] Smith TO, Dixon J, Bowyer D, Davies L, Donell ST. The relative onset timing and EMG activity of VMO and VL in patellar instability: a systematic review. Phys Ther Rev 2008;10:405–15.

[16] CASP (Critical Skills Appraisal Programme) homepage. Oxford: Learning & Development Public Health Resource Unit, 2007. Available at: http://www.phru.nhs.uk/casp/critical.appraisal-tools.htm (last accessed 01/08/2009). [17] Moher D, Liberati A, Tetzlaff J, Altman DG, the PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. BMJ 2009;339:332–6. [18] Mäenpää H, Huhtala H, Lehto MUK. Recurrence after patellar dislocation. Redislocation in 37/75 patients followed for 6–24 years. Acta Orthop Scand 1997;68:424–6. [19] Marcacci M, Zaffagnini S, Iacono F, Visani A, Petitto A, Neri NP. Results in the treatment of recurrent dislocation of the patella after 30 years’ follow-up. Knee Surg Sports Traumatol Arthrosc 1995;3:163–6. [20] Savarese A, Lunghi E. Traumatic dislocations of the patella: problems related to treatment. Chir Organi Mov 1990;75:51–7. [21] McManus F, Rang M, Heslin DJ. Acute dislocation of the patella in children. Clin Orthop 1979;139:88–91. [22] Bohannon RW. Effect of electrical stimulation to the vastus medialis muscle in a patient with chronically dislocating patellae. A case report. Phys Ther 1983;63:1445–7. [23] Osterhues DJ. The use of Kinesio Taping® in the management of traumatic patella dislocation. A case study. Physiother Theory Pract 2004;20:267–70. [24] Racouillat M. Use of plyometrics in the rehabilitation of a female lacrosse player following patellar dislocation. Orthop Pract 2007;19:189–94. [25] Nikku R, Nietosvaara Y, Aalto K, Kallio PE. Operative treatment of primary patellar dislocation does not improve medium-term outcome. A 7-year follow-up report and risk analysis of 127 randomized patients. Acta Orthop 2005;76:699–704. [26] Arnbjörnsson A, Egund N, Rydling O, Stockerup R, Ryd L. The natural history of recurrent dislocation of the patella. Long-term results of conservative and operative treatment. J Bone Joint Surg 1992;74–B:140–3. [27] Hawkins RJ, Bell RH, Anisette G. Acute patellar dislocations. The natural history. Am J Sports Med 1986;14:117–20. [28] Kujala UM, Jaakkola LH, Koskinen SK, Taimela S, Hurme M, Nelimarkka O. Scoring of patellofemoral disorders. Arthroscopy 1993;9:159–63. [29] Palmu S, Kallio PE, Donell ST, Helenius I, Nietosvaara Y. Acute patellar dislocation in children and adolescents: a randomized clinical trial. J Bone Joint Surg 2008;90-A:463–70. [30] Mäenpää H, Lehto MUK. Patellar dislocation. The long-term results of nonoperative management in 100 patients. Am J Sport Med 1997;25:213–7. [31] Sillanpää PJ, Mäenpää HM, Mattila VM, Visuri T, Pihlajamäki H. Arthroscopic surgery for primary traumatic patellar dislocation. A prospective, nonrandomized study comparing patients treated with and without acute arthroscopic stabilization with a median 7-year followup. Am J Sport Med 2008;36:2301–9. [32] Sillanpää PJ, Mattila VM, Mäenpää H, Kiuru M, Visuri T, Pihlajamäki H. Treatment with and without initial stabilizing surgery for primary traumatic patellar dislocation. J Bone Joint Surg 2009;91-A:263–73. [33] Sillanpää PJ, Peltola E, Mattila VM, Kiuru M, Visuri T, Pihlajamäki H. Femoral avulsion of the medial patellofemoral ligament after primary traumatic patellar dislocation predicts subsequent instability in men: a mean 7-year nonoperative follow-up study. Am J Sports Med 2009;37:1513–21. [34] Camanho GL, Viegas AdC, Bitar AC, Demange MK, Hernandez AJ. Conservative versus surgical treatment for repair of the medial patellofemoral ligament in acute dislocations of the patella. Arthroscopy 2009;25:620–5. [35] Christiansen SE, Jakobsen BW, Lund B, Lind M. Isolated repair of the medial patellofemoral ligament in primary dislocation of the patella: a prospective randomised study. Arthroscopy 2008;24:881–7. [36] Lysholm J, Gillquist J. Evaluation of knee ligament surgery results with special emphasis on use of a scoring scale. Am J Sport Med 1982;10:150–4.

T.O. Smith et al. / Physiotherapy 96 (2010) 269–281 [37] Nikku R, Nietosvaara Y, Kallio PE, Aalto K, Michelsson J-E. Operative versus closed treatment of primary dislocation of the patella. Similar 2-year results in 125 randomized patients. Acta Orthop Scand 1997;68:419–23. [38] Flandry F, Hunt JP, Terry GC, Hughston JC. Analysis of subjective knee complaints using visual analogue scales. Am J Sports Med 1991;19:112–8. [39] Tegner Y, Lysholm J. Rating systems in the evaluation of knee ligament injuries. Clin Orthop Relat Res 1985;198:43–9. [40] Larsen E, Lauridsen F. Conservative treatment of patellar dislocations. Influence of evident factors on the tendency to re-dislocation and the therapeutic result. Clin Orthop Relat Res 1982;171:131–6. [41] Crosby EB, Insall J. Recurrent dislocation of the patella: relation of treatment to osteoarthritis. J Bone Joint Surg 1976;58A:9–13. [42] Heywood AWB. Recurrent dislocation of the paella. A study of its pathology and treatment in 106 knees. J Bone Joint Surg 1961;43B:508–17. [43] Binkley JM, Stratford PW, Lott SA, Riddle DL. The Lower Extremity Functional Scale (LEFS): scale development, measurement properties, and clinical application. North American Orthopaedic Rehabilitation Research Network. Phys Ther 1999;79:371–83. [44] Helgeson K, Smith AR. Process for applying the International Classification of Functioning, Disability and Health model to a patient with patellar dislocation. Phys Ther 2008;88:956–64. [45] Hall JE, Micheli LJ, McManama Jr GB. Semitendinosus tenodesis for recurrent subluxation or dislocation of the patella. Clin Orthop Relat Res 1979;144:31–5. [46] Hvass I, Johnsen F, Frandsen PA. Conservative treatment of patellar dislocation. Orthop Scand 1988;59:739–47. [47] Roos EM, Roos HP, Lohmander LS, Ekdahl C, Beynnon BD. Knee Injury and Osteoarthritis Outcome Score (KOOS)—development of a self-administered outcome measure. J Orthop Sports Phys Ther 1998;28:88–96. [48] Pedersen P, Pedersen T. Conservative treatment of acute patellar dislocation. Adv Orthop Surg 1989;12:205–7.

281

[49] Mäenpää H, Latvala K, Lehto MUK. Isokinetic thigh muscle performance after long-term recovery from patellar dislocation. Knee Surg Sports Traumatol Arthrosc 2000;8:109–12. [50] Atkins DM, Fithian DC, Marangi KS, Stone ML, Dobson BE, Mendelsohn C. Characteristics of patients with primary acute lateral patellar dislocation and their recovery within the first 6 months of injury. Am J Sport Med 2000;28:472–9. [51] Medical Research Council. Aids to the examination of the peripheral nervous system. Memorandum no. 45. London: Her Majesty’s Stationery Office; 1981. [52] Longhurst JC, Stebbins CL. The isometric athlete. Cardiol Clin 1992;10:281–94. [53] Polgar S, Thomas SA. Introduction to research in the health sciences. 4th ed. London: Churchill Livingstone; 2000. [54] Garth WP, Pomphrey M, Merill K. Functional treatment of patellar dislocation in an athletic population. Am J Sports Med 1996;24: 785–91. [55] Boden BP, Pearsall AW, Garrett WE, Feagin JA. Patellofemoral instability: evaluation and management. J Am Acad Orthop Surg 1997;5:47–57. [56] Grimby G, Gustaffson E, Peterson L, Renström P. Quadriceps function and training after knee ligament surgery. Med Sci Sports Exerc 1980;12:70–5. [57] Kannus P, Jozsa L, Renström P, Järvinen M, Kvist M, Lehto M, et al. The effects of training, immobilization and remobilization on musculoskeletal tissue. Scand J Med Sci Sports 1992;2:100–18. [58] McConnell J. Rehabilitation and nonoperative treatment of patellar instability. Sports Med Arthrosc Rev 2007;15:95–104. [59] Scharf W, Weinstabl R, Kwasny O, Schratter M. Therapeutic measures in subluxation and dislocation of the patella. Unfallchirurgie 1991;17:225–31. [60] Howell GED. Knee. In: Bulstrode C, Buckwalter J, Carr A, Marsh L, Fairbank J, Wilson-McDonald J, Bowden G, editors. Oxford textbook of orthopaedics and trauma, vol. 2. Oxford: Oxford University Press; 2002. p. 1107–216.

Available online at www.sciencedirect.com