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Prevalence and sensitivity of trigger points in lumbo-pelvic-hip muscles in patients with patellofemoral pain syndrome
Journal Pre-proof Prevalence and sensitivity of trigger points in lumbo-pelvic-hip muscles in patients with patellofemoral pain syndrome Mahbobeh Samani, Farahnaz Ghaffarinejad, Sara Abolahrari-Shirazi, Tahereh Khodadadi, Fatemeh Roshan PII:
S1360-8592(19)30324-9
DOI:
https://doi.org/10.1016/j.jbmt.2019.10.012
Reference:
YJBMT 1896
To appear in:
Journal of Bodywork & Movement Therapies
Received Date: 5 October 2019 Accepted Date: 12 October 2019
Please cite this article as: Samani, M., Ghaffarinejad, F., Abolahrari-Shirazi, S., Khodadadi, T., Roshan, F., Prevalence and sensitivity of trigger points in lumbo-pelvic-hip muscles in patients with patellofemoral pain syndrome, Journal of Bodywork & Movement Therapies, https://doi.org/10.1016/j.jbmt.2019.10.012. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier Ltd.
Title page Prevalence and sensitivity of trigger points in lumbo-pelvic-hip muscles in patients with patellofemoral pain syndrome Mahbobeh Samani1, Farahnaz Ghaffarinejad2, Sara Abolahrari-Shirazi2, Tahereh Khodadadi3, Fatemeh Roshan3 1. Student Research Committee, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran 2. Ph.D., Department of Physical Therapy, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran 3. BS, Department of Physical Therapy, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran Corresponding author: Sara Abolahrari-Shirazi Email: [email protected] Declarations of interest: none
ABSTRACT Objectives: Changes in the activity of the lumbo-pelvic-hip muscles have been established as a major cause of patellofemoral pain syndrome (PFPS), a common orthopedic problem. The present study aimed to compare the prevalence and sensitivity of myofascial trigger points (MTrPs) in lumbo-pelvic-hip muscles in persons with and without PFPS. Methods: Thirty women with PFPS and 30 healthy women 18 to 40 years old were recruited for this study. The prevalence of MTrPs was assessed by palpation, and pressure algometry was used to measure the pressure pain threshold. This study evaluated the areas where MTrPs are most commonly found in the lumbar muscles (internal oblique, erector spinae and quadratus lumborum), pelvic muscles (gluteus maximus, gluteus medius, gluteus minimus and piriformis), and hip muscles (hip adductor, quadriceps, hamstring, tensor fascia lata and sartorius). Independent t-tests were used to compare mean pressure pain thresholds between the two groups. Chi-squared tests were used to compare the prevalence of MTrPs. Results: The prevalence of MTrPs was significantly higher in most of the lumbo-pelvic-hip muscles in patients with PFPS compared to healthy persons. However, there were no significant differences between groups in the prevalence of MTrPs in the gluteus minimus or adductor muscles. The pressure pain threshold in lumbo-pelvic-hip muscles was lower in patients with PFPS compared to healthy participants. Conclusion: In patients with PFPS the prevalence of MTrPs in the lumbo-pelvic-hip region was higher, and the pressure pain threshold was lower, than in healthy people. Thus therapy to treat PFPS should target the lumbo-pelvic-hip muscles.
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Keywords: trigger points, lumbo-pelvic-hip, patellofemoral pain syndrome, prevalence
BACKGROUND Patellofemoral pain syndrome (PFPS) is a common source of anterior knee pain, which predominantly affects young female patients (O’Sullivan & Popelas 2005). Although the main cause of PFPS is still unclear (Nijs et al. 2006), patellar maltracking as a result of imbalance in the vastus medialis obliques and vastus lateralisis the most likely mechanism (Fagan & Delahunt 2008). Another assumed etiology of PFPS is impaired function of proximal structures such as the lumbo-pelvic-hip muscles (Aminaka et al. 2011, Biabanimoghadam et al. 2016, Cowan et al. 2009). Several studies have found that patients with PFPS have impaired lumbo-pelvic-hip muscle function as a result or cause of PFPS, a finding supported by Motealleh et al. (Motealleh et al. 2015), Cowan et al. (Cowan et al. 2009), Robinson and Nee (Robinson & Nee 2007), Piva et al. (Piva et al. 2005), and Ireland et al. (Ireland et al. 2003). One possible cause of impaired lumbo-pelvic-hip muscle function is the formation of myofascial trigger points (MTrPs). These are described as hyperirritable spots in the fascia surrounding skeletal muscles, that elicit local pain and refer it to another region (Kanner 2003). Trigger points may result from or be exacerbated by trauma, overuse, mechanical overload, postural faults, or psychological stress (Jafri 2014). The presence of MTrPs in muscles results in impaired motor function and motor control (Lucas et al. 2010), as well as decreased muscle tone and muscle strength (Kanner 2003). Therefore, the presence of MTrPs in lumbo-pelvic-hip muscles may impair proximal stability via
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the mechanisms noted above. Proximal instability, in turn, can lead to impaired muscle function in the lower extremities and consequent exacerbation of PFPS (Brumitt 2009). Thus, the evidence appears to support that therapists should target the lumbo-pelvic-hip region in the treatment of PFPS (Ellenbecker 2000). However, due to the large number of lower extremity and lumbar muscles, and the high frequency of MTrPs in these regions, not all MTrPs may need to be treated during therapy. To the best of our knowledge, there is no evidence regarding the most common MTrPs located in the lumbo-pelvic-hip muscles. Evidence of the relative prevalences of MTrPs in different locations would help therapists to target them during treatment, yet most available studies evaluated the prevalence of MTrPs in hip muscles. Therefore, the present study aimed to compare the prevalence of MTrPs in different lumbopelvic-hip muscles in patients with PFPS compared to healthy persons. METHODS Sample size In this retrospective cross-sectional study, 30 patients with PFPS and 30 healthy persons between 18 and 40 years old were recruited. Sample size was estimated with a sample size calculator (α=0.05, 1-β=0.9, d=0.2) (Roach et al. 2013). Patients with PFPS were recruited among randomly selected physiotherapy and rehabilitation clinics, and healthy participants were selected among staff members and students at Shiraz University of Medical Sciences. Participants in both groups were matched for age, height and weight. Inclusion criteria •
Women 18 to 40 years old with anterior knee pain (Hudson & Darthuy 2009)
•
Pain in the anterior knee during running, jumping, squatting, climbing stairs or sitting for
a prolonged period with bent knees (Cowan et al. 2002)
3
•
Pain in the retropatellar region (Cichanowski et al. 2007)
•
Unexpected onset of symptoms, which lasted for over 3 months (chronic pain)
•
Positive patellar grind test
•
Functional Index Questionnaire score of 11 or higher (Aminaka et al. 2011)
•
Pain visual analog scale (VAS) score of at least 3 out of 10 during the previous30 days
(Magee 2014) •
Signature provided on the written informed consent form
Exclusion criteria •
History of thigh, knee or ankle joint surgery
•
History of patellar dislocation
•
History of meniscus injury
•
History of ligament instability
•
Pain in the patellar tendon
•
Articular cartilage lesion
•
Myofascial pain syndrome
•
Use of atorvastatin or any other drugs that led to muscle pain
•
Joint inflammation within the previous year
•
Pregnancy or breastfeeding
•
Neuromuscular or central nervous system diseases
•
Metabolic diseases such as diabetes or rheumatoid arthritis
•
Professional athletes
Procedures
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The inclusion and exclusion criteria were initially evaluated by the first examiner. Then participants were informed of the study objectives and asked to provide their consent in writing to take part. This study was approved by the local Ethics Committee of Shiraz University of Medical Sciences (Ethics code: IR.SUMS.REC.1394.S730). The prevalence and pressure pain threshold of MTrPs in the two groups were assessed by a second examiner, who was blinded to the study protocols. First, the most common locations of MTrPs in each muscle under investigation was marked with a marker. Then the presence of MTrPs was identified by palpation, according to the criteria proposed by Travell and Simons (Simons et al. 1999), which include 1) taut band within a skeletal muscle, 2) tenderness in taut bands, 3) a local twitch response on palpation of the taut band, 4) referred pain elicited on palpation of the taut band, and 5) spontaneous pain in the immediately surrounding tissues and/or distant sites in specific referred pain patterns. The presence of at least one perceived painful spot in a taut band was sufficient for the identification of MTrPs in this study (Simons et al. 1999). Muscles in the lumbar region Muscles examined in the lumbar region were the internal oblique, erector spinae and quadratus lumborum. Muscles in the pelvic region Muscles examined in the pelvic region were the gluteus maximus, gluteus medius, gluteus minimus and piriformis. Muscles in the hip region Muscles examined in the hip region were the quadriceps, hamstring, tensor fascia lata, adductor and sartorius. Pressure pain threshold detection
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After detecting the MTrPs, the pressure pain threshold (recorded as the force in kg/cm2) was measured in each muscle with a pressure algometer (FDIX25 Digital Force Gauge, Greenwich, CT, USA). The algometer was placed on the skin over the muscle and pressure was applied at an angle of 90 degrees flexion (Tsai et al. 2000). The participants were asked to report pain as soon as they felt it. Measurements were repeated twice at 30-seconds intervals between trials, and the mean trial pressure pain was calculated and recorded as the final pressure pain threshold (Aparicio et al. 2013). Statistical methods The Kolmogorov–Smirnov test showed that the data were distributed normally. The chi-squared test was used to compare the prevalence of MTrPs between the two groups, and independent ttests were used to compare pressure pain thresholds and demographic characteristics between the two groups. P-values ≤0.05 were considered statistically significant. RESULTS Demographic characteristics The findings showed no significant differences in age, height or weight between the two groups (Table 1). PLACE TABLE 1 HERE. MTrPs in lumbar muscles The prevalence of MTrPs in lumbar muscles was significantly higher in patients with PFPS compared to healthy participants (Table 2). The pressure pain threshold of MTrPs in muscles of the lumbar region was significantly lower in patients with PFPS than in healthy participants (Table3). PLACE TABLE 2 AND 3 HERE.
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MTrPs in pelvic muscles The prevalence of MTrPs in the gluteus maximus, gluteus medius and piriformis muscles was significantly higher in the PFPS group compared to healthy persons. However, there was no significant difference between groups in the prevalence of MTrPs in the gluteus minimus (Table4). The pressure pain threshold of MTrPs in pelvic muscles was significantly lower in patients with PFPS compared to healthy participants (Table 5). PLACE TABLE 4 AND 5 HERE. MTrPs in hip muscles The prevalence of MTrPs in the tensor fascia lata, sartorius, rectus femoris, vastus medialis, vastus lateralis, biceps femoris, semitendinosus and semimembranosus muscles was significantly higher in patients with PFPS than in the healthy group. However, there was no significant difference between groups in the prevalence of MTrPs in adductor muscles (Table 6). The pressure pain threshold of MTrPs in muscles of the hip region was significantly lower in patients with PFPS compared to healthy participants (Table 7). PLACE TABLE 6 AND 7 HERE. DISCUSSION Prevalence of MTrPs and pressure pain threshold in lumbar muscles The prevalence of MTrPs in lumbar muscles was significantly higher in patients with PFPS than healthy persons. Also, the pressure pain threshold in lumbar region muscles was significantly lower in patients with PFPS than healthy participants. The higher prevalence of MTrPs in the lumbar region in patients with PFPS might be due to the impaired function of these muscles as a result or cause of PFPS. Lumbar muscles act as eccentric stabilizers of the trunk region. Impaired proximal stability in patients with PFPS may increase the load on these muscles, and thus lead to
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the formation of MTrPs and lowered pressure pain thresholds (Mascal et al. 2003). Many studies have proposed a direct relationship between impaired proximal stability and PFPS (Cowan et al.2009), but only Roach et al. (Roach et al. 2013) evaluated MTrPs in the quadratus lumborum muscle in patients with PFPS; they reported a higher prevalence of MTrPs in patients with PFPS compared to healthy individuals, which was in line with the findings of the present study. Prevalence of MTrPs and pressure pain threshold in pelvic muscles The results reported here show that the prevalence of MTrPs in the gluteus maximus, gluteus medius and piriformis muscles was significantly higher in patients with PFPS than in healthy persons, but there was no significant difference between groups in the prevalence of MTrPs in the gluteus minimus. In addition, the pressure pain threshold in all pelvic region muscles was significantly lower in patients with PFPS. The gluteus maximus is the main extensor muscle of the hip, and the gluteus medius is one of the main hip abductors that stabilizes the hip joint in the frontal plane. The piriformis muscle is an external rotator of the hip, acting as a tonic stabilizer of the hip joint (Simons et al. 1999). Robinson et al. found that 25% to 50% of patients with PFPS had reduced strength in the abductor, extensor and external rotator muscles. These weaknesses made patients with PFPS more likely to develop MTrPs, with a lower pressure pain threshold in these muscles compared to healthy persons (Robinson & Nee 2007). Rouch et al. found that the prevalence of MTrPs in the gluteus medius was significantly higher in patients with PFPS than in healthy people, which was in line with the results reported in the present study (Roach et al. 2013). Given that the gluteus minimus is not a main extensor, abductor or rotator of the hip, weakness and consequently trigger point formation may be less frequent in this muscle in patients with PFPS.
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This may explain why we found no difference in the prevalence of trigger points in this muscle between patients with PFPS and healthy persons. Prevalence of MTrPs and pressure pain threshold in hip muscles The prevalence of MTrPs in hip muscles, except for the adductor muscles, was significantly higher in patients with PFPS than in healthy participants. In addition, the pressure pain threshold in hip region muscles was significantly lower in patients with PFPS compared to healthy persons. The present findings showed that all participants with PFPS had MTrPs in the quadriceps muscle bellies, in consonance with earlier results reported by Smith (Smith 2012) and Daly (Daly 2005). Among the quadriceps muscles, MTrPs were most prevalent in the vastus lateralis, which may reflect the greater likelihood of MTrP formation in the fibers of this muscle, as reported previously (Smith 2012). This result is also consistent with an earlier study by Dippenaar (Dippenaar 2003). However, in contrast to the present results, Smith found that among quadriceps muscles, MTrPs were most prevalent in the vastus medialis (Smith 2012). In the present study the prevalence of MTrPs in the rectus femoris was 76.7%, a figure very similar to the 76.3% prevalence of MTrPs reported in an earlier study of patients with PFPS (Dippenaar 2003). In contrast, Smith (Smith 2012) found a prevalence of MTrPs in the rectus femoris of only 8.8%. This difference between studies may be the result of gender differences, given that the majority of participants in the study by Smith were males, whereas all participants in the present study were females. It has been reported that females exhibit higher quadriceps activity compared to males during the same tasks (Chappell et al. 2007, Krishnan et al. 2008). The higher quadriceps activity may cause a greater load on the rectus femoris muscle, which may account for the higher prevalence of trigger points in the rectus femoris in our study (with female participants) compared to Smith’s study (with male participants). In addition, differences in
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anatomical, hormonal or neuromuscular factors between males and females (Mendiguchia et al. 2011) may explain the different prevalences of trigger points in the rectus femoris in the present study and Smith’s study. The prevalence of MTrPs in hamstring muscles was 96.6% in the present study, a figure similar to the 86.3% prevalence found by Smith (Smith 2012). The higher prevalence of MTrPs in hamstring muscles in patients with PFPS compared to healthy persons may be due to the greater likelihood of hamstring muscle shortness in patients with PFPS than in healthy individuals (White et al. 2009). Moreover, reduced lateral patellar tracking in patients with PFPF increases the likelihood of MTrP development in the hamstring muscles compared to healthy persons (White et al. 2009). According to the present results, the prevalence of MTrPs in the tensor fascia lata was significantly higher in patients with PFPS than in healthy persons. No previous studies have specifically focused on the prevalence of MTrPs in this muscle in patients with PFPS. The sartorius is an abductor muscle that functions as an important flexor and external rotator of the hip joint (Simons et al. 1999). Weakened abduction and rotation strength in patients with PFPS may lead to increased loads on this muscle, which in turn may result in a higher prevalence of MTrPs and lower pressure pain threshold compared to healthy individuals (Page et al. 2010). The present results showed a high prevalence of MTrPs in adductor muscles in both groups: 96.7% in patients with PFPS and 83.3% in healthy persons. This finding is consistent with the high prevalence of MTrPs (64%) in adductor muscles that was reported in a previous study of patients with PFPS (Smith 2012). The higher prevalence of MTrPs in adductor muscles
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in both groups may be due to the location of this muscle in a sensitive area of the body, especially in women (Smith 2012). LIMITATIONS Because psychological and emotional stress may activate MTrPs (Dommerholt et al. 2006), it would have been informative to assess emotional parameters in our participants at baseline. However, the short assessment period meant that we were not able to assess these factors. In addition, because of the high number of lumbo-pelvic-hip muscles we did not evaluate trigger points in all of the muscles in this region. Furthermore, because of differences between males and females in anatomical, hormonal and neuromuscular factors (Mendiguchia et al. 2011), the prevalence of trigger points may differ between men and women. Accordingly, the results of the present study are not generalizable to males. Additional research is required to compare the prevalence of trigger points between males and females with PFPS, and to determine the prevalence of trigger points in other muscles of the lumbo-pelvic-hip region. Another factor that merits further research is emotional status and how it might affect the response to treatment. Future studies should also compare the prevalence of MTrPs on both sides in patients with PFPS and healthy people. CONCLUSION The prevalence of MTrPs was higher, and pressure pain threshold in the lumbo-pelvic-hip muscles was lower, in patients with PFPS than in healthy participants. CLINICAL RELEVANCE •
Therapists can target trigger points in lumbo-pelvic-hip muscles during treatment in patients with PFPS.
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•
Given the absence of significant differences in trigger points in the gluteus minimus and adductor muscles between people with PFPS and healthy people, therapists may target the trigger points in these two muscles as a second priority compared to other lumbopelvic-hip muscles that were investigated in this study.
ACKNOWLEDGEMENTS This work was supported by Shiraz University of Medical Sciences. The authors wish to thank Mr. H. Argasi at the Research Consultation Center of Shiraz University of Medical Sciences for his invaluable assistance in editing this manuscript, and K. Shashok (AuthorAID in the Eastern Mediterranean) for improving the use of English in the manuscript.
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Daly G 2005 The Relationship Between Myofascial Trigger Points, Total Work and Other Recorded Measurements of the Vastus Lateralis and Vastus Medialis, in Long-Distance Runners with Patellofermoral Pain Syndrome (thesis). M. Tech: Chiropractic, Durban University of Technology, Durban, South Africa. Dippenaar D 2003 The association between myofascial trigger points of the Quadriceps femoris muscle group and the clinical presentation of patellofemoral pain syndrome using a piloted patellofemoral pain severity rating scale (thesis). M. Tech: Chiropractic, Durban University of Technology, Durban, South Africa. Dommerholt J, Bron C, Franssen J 2006 Myofascial trigger points: an evidence-informed review, Journal of Manual & Manipulative Therapy. 14, 203-221. Ellenbecker T.S 2000 Knee Ligament Rehabilitation, Churchill Livingstone, Edinburgh. Fagan V,Delahunt E 2008 Patellofemoral pain syndrome: a review of the associated neuromuscular deficits and current treatment options, British Journal of Sports Medicine. 42, 10: 789-95. Hudson Z, Darthuy E 2009 Iliotibial band tightness and patellofemoral pain syndrome: a casecontrol study, Manual Therapy. 14, 2: 147-51. Ireland M.L, Willson J.D, Ballantyne B.T,Davis I.M 2003 Hip strength in females with and without patellofemoral pain, Journal of Orthopaedic &Sports Physical Therapy. 33, 11: 671-6. Jafri MS 2014 Mechanisms of myofascial pain, International Scholarly Research Notices. 2014. Kanner R 2003 Pain Management Secrets, Hanley &Belfus,Philadelphia. Krishnan C, Huston K, Amendola A, Williams G. N 2008 Quadriceps and hamstrings muscle control in athletic males and females, Journal of Orthopaedic Research. 26, 800-808.
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Lucas K.R, Rich P.A, Polus B.I 2010 Muscle activation patterns in the scapular positioning muscles during loaded scapular plane elevation: the effects of latent myofascial trigger points, Clinical Biomechanics. 25, 8: 765-70. Magee D.J 2014 Orthopedic Physical Assessment, Elsevier Health Sciences. Mascal C.L, Landel R,Powers C 2003 Management of patellofemoral pain targeting hip, pelvis, and trunk muscle function: 2 case reports, Journal of Orthopaedic & Sports Physical Therapy. 33, 11: 647-60. Mendiguchia J, Ford K. R, Quatman C. E, Alentorn-Geli E, Hewett T. E 2011 Sex differences in proximal control of the knee joint, Sports Medicine. 41, 541-557. Motealleh A, Maroufi N, Sarrafzadeh J, Sanjari M.A, Salehi N 2015 Comparative Evaluation of Core and Knee Extensor Mechanism Muscle Activation Patterns in a Stair Stepping Task in Healthy Controls and Patellofemoral Pain Patients, Journal of Rehabilitation Sciences and Research.1,4: 84-91. Nijs J, Van Geel C, Van de Velde B 2006 Diagnostic value of five clinical tests in patellofemoral pain syndrome, Manual Therapy. 11, 1: 69-77. O'Sullivan S.P,Popelas C.A 2005 Activation of vastus medialis obliquus among individuals with patellofemoral pain syndrome, The Journal of Strength & Conditioning Research. 19, 2: 302-4. Page P, Frank C,Lardner R 2010 Assessment and Treatment of Muscle Imbalance: The Janda Approach, Human Kinetics,Champaign. Piva S.R, Goodnite E.A,Childs J.D 2005 Strength around the hip and flexibility of soft tissues in individuals with and without patellofemoral pain syndrome, Journal of Orthopaedic &Sports Physical Therapy.35, 12: 793-801.
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Roach S, Sorenson E, Headley B,San Juan J.G 2013 Prevalence of myofascial trigger points in the hip in patellofemoral pain, Archives of Physical Medicine and Rehabilitation.94, 3: 522-6. Robinson R.L,Nee R.J 2007 Analysis of hip strength in females seeking physical therapy treatment for unilateral patellofemoral pain syndrome, Journal of Orthopedic &Sports Physical Therapy.37, 5: 232-8. Simons D.G, Travell J.G,Simons L.S 1999 Travell & Simons Myofascial Pain and Dysfunction: Upper Half of Body, vol. 1, Lippincott Williams & Wilkins,Philadelphia. Smith K.L.F 2012 The Role of and Relationship Between Hamstring and Quadriceps Muscle Myofascial Trigger Points in Patients with Patellofemoral Pain Syndrome(thesis). M. Tech: Chiropractic, Durban University of Technology, Durban, South Africa. Souza R.B 2008 The Influence of Hip and Femur Kinematics on Patellofemoral Joint Dysfunction, ProQuest,Ann Arbor. Tsai W.C, Wang C.L, Tang, F.T, Hsu T.C, Hsu K.H, Wong M.K 2000 Treatment of proximal plantar fasciitis with ultrasound-guided steroid injection, Archives of Physical Medicine and Rehabilitation. 81, 10: 1416-21. White L.C, Dolphin P, Dixon J 2009 Hamstring length in patellofemoral pain syndrome, Physiotherapy. 95, 1: 24-8.
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TABLES Table 1. Demographic characteristics of participants in the PFPS and healthy groups
Items
PFPS group
Healthy group
P value
Age (years)
22.1 ± 1.5
22.1 ± 1.1
0.926
Height (cm)
162.0 ± 7.3
164.8 ± 6.2
0.109
Weight (kg)
57.8 ± 11.0
56.4 ± 10.1
0.611
1
Table 2. Prevalence of lumbar MTrPs in the two groups Muscle
Prevalence
PFPS group
Healthy group
P value
IO
Number
24
10
<0.001*
Percent
80.0%
33.0%
Number
21
8
Percent
70.0%
26.7%
Number
23
8
Percent
76.7%
26.7%
QL
ES
0.001*
<0.001*
Abbreviations: MTrPs: Myofascial trigger points, IO: Internal oblique, QL: Quadratus lumborum, ES: Erector spinae *Significant difference
2
Table 3. Pain threshold in lumbar MTrPs in the two groups Muscle
PFPS group
Healthy group
P value
IO
1.19±0.64
1.97±0.78
<0.001*
QL
1.39±0.86
2.92±1.46
<0.001*
ES
1.31±0.88
3.19±1.46
<0.001*
Abbreviations: MTrPs: Myofascial trigger points, IO: Internal oblique, QL: Quadratus lumborum, ES: Erector spinae *Significant difference
3
Table 4. Prevalence of pelvic MTrPs in the two groups Muscle
Prevalence
PFPS group
Healthy group
P value
GMax
Number
18
4
0.006*
Percent
60.0%
13.3%
Number
27
17
Percent
90.0%
56.7%
Number
28
23
Percent
93.3%
76.7%
Number
23
13
Percent
76.7%
43.3%
GMed
GMin
Piriformis
0.004*
0.071
0.001*
Abbreviations: MTrPs: Myofascial trigger points, GMax: Gluteus maximus, GMed: Gluteus medius, GMin: Gluteus minimus *Significant difference
4
Table 5. Pain threshold in pelvic MTrPs in the two groups Muscle
PFPS group
Healthy group
P value
1st MTrPs in GMax
1.81±1.19
3.59±1.88
<0.001*
GMed
1.17±0.59
2.61±1.20
<0.001*
GMin
1.10±0.70
1.62±0.62
0.003*
1st MTrPs in piriformis
1.52±1.02
3.17±1.41
<0.001*
Abbreviations: MTrPs: Myofascial trigger points, GMax: Gluteus maximus, GMed: Gluteus medius, GMin: Gluteus minimus *Significant difference
5
Table 6. Prevalence of hip MTrPs in the two groups Muscle
Prevalence
PFPS group
Healthy group
P value
TFL
Number
19
7
0.002*
Percent
63.3%
23.3%
Number
23
12
Percent
76.7%
40.0%
Number
17
9
Percent
56.7%
30.0%
Number
20
4
Percent
66.7%
13.3%
Number
23
6
Percent
76.7%
20.0%
Number
27
16
Percent
90.0%
53.3%
Number
26
15
Percent
86.7%
50.0%
RF
Sartorius
VM
VL
ST&SM
BF
6
0.004*
0.030*
<0.001*
<0.001*
0.002*
0.002*
Add
Number
29
25
Percent
96.7%
83.3%
0.085
Abbreviations: MTrPs: Myofascial trigger points, TFL: Tensor fascia lata, RF: Rectus femoris, VM: Vastus medialis, VL: Vastus lateralis, ST&SM: Semimembranosus and semitendinosus, BF: Biceps femoris, Add: Adductor *Significant difference
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Table 7. Pain tolerance in hip MTrPs in the two groups Muscle
PFPS group
Healthy group
P value
TFL
2.17±1.64
3.69±1.53
<0.001*
RF
1.86±1.25
3.10±1.37
0.001*
Sartorius
2.32±1.59
3.61±1.56
0.003*
VM
1.56±1.00
3.35±0.91
<0.001*
VL
1.48±0.94
3.36±1.41
<0.001*
ST&SM
0.85±0.62
2.46±1.37
<0.001*
BF
1.16±0.64
2.78±1.66
<0.001*
Add
0.77±0.23
1.28±0.47
<0.001*
Abbreviations: MTrPs: Myofascial trigger points, TFL: Tensor fascia lata, RF: Rectus femoris, VM: Vastus medialis, VL: Vastus lateralis, ST&SM: Semimembranosus and semitendinosus, BF: Biceps femoris, Add: Adductor
8
S1360-8592(19)30324-9
DOI:
https://doi.org/10.1016/j.jbmt.2019.10.012
Reference:
YJBMT 1896
To appear in:
Journal of Bodywork & Movement Therapies
Received Date: 5 October 2019 Accepted Date: 12 October 2019
Please cite this article as: Samani, M., Ghaffarinejad, F., Abolahrari-Shirazi, S., Khodadadi, T., Roshan, F., Prevalence and sensitivity of trigger points in lumbo-pelvic-hip muscles in patients with patellofemoral pain syndrome, Journal of Bodywork & Movement Therapies, https://doi.org/10.1016/j.jbmt.2019.10.012. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier Ltd.
Title page Prevalence and sensitivity of trigger points in lumbo-pelvic-hip muscles in patients with patellofemoral pain syndrome Mahbobeh Samani1, Farahnaz Ghaffarinejad2, Sara Abolahrari-Shirazi2, Tahereh Khodadadi3, Fatemeh Roshan3 1. Student Research Committee, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran 2. Ph.D., Department of Physical Therapy, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran 3. BS, Department of Physical Therapy, School of Rehabilitation Sciences, Shiraz University of Medical Sciences, Shiraz, Iran Corresponding author: Sara Abolahrari-Shirazi Email: [email protected] Declarations of interest: none
ABSTRACT Objectives: Changes in the activity of the lumbo-pelvic-hip muscles have been established as a major cause of patellofemoral pain syndrome (PFPS), a common orthopedic problem. The present study aimed to compare the prevalence and sensitivity of myofascial trigger points (MTrPs) in lumbo-pelvic-hip muscles in persons with and without PFPS. Methods: Thirty women with PFPS and 30 healthy women 18 to 40 years old were recruited for this study. The prevalence of MTrPs was assessed by palpation, and pressure algometry was used to measure the pressure pain threshold. This study evaluated the areas where MTrPs are most commonly found in the lumbar muscles (internal oblique, erector spinae and quadratus lumborum), pelvic muscles (gluteus maximus, gluteus medius, gluteus minimus and piriformis), and hip muscles (hip adductor, quadriceps, hamstring, tensor fascia lata and sartorius). Independent t-tests were used to compare mean pressure pain thresholds between the two groups. Chi-squared tests were used to compare the prevalence of MTrPs. Results: The prevalence of MTrPs was significantly higher in most of the lumbo-pelvic-hip muscles in patients with PFPS compared to healthy persons. However, there were no significant differences between groups in the prevalence of MTrPs in the gluteus minimus or adductor muscles. The pressure pain threshold in lumbo-pelvic-hip muscles was lower in patients with PFPS compared to healthy participants. Conclusion: In patients with PFPS the prevalence of MTrPs in the lumbo-pelvic-hip region was higher, and the pressure pain threshold was lower, than in healthy people. Thus therapy to treat PFPS should target the lumbo-pelvic-hip muscles.
1
Keywords: trigger points, lumbo-pelvic-hip, patellofemoral pain syndrome, prevalence
BACKGROUND Patellofemoral pain syndrome (PFPS) is a common source of anterior knee pain, which predominantly affects young female patients (O’Sullivan & Popelas 2005). Although the main cause of PFPS is still unclear (Nijs et al. 2006), patellar maltracking as a result of imbalance in the vastus medialis obliques and vastus lateralisis the most likely mechanism (Fagan & Delahunt 2008). Another assumed etiology of PFPS is impaired function of proximal structures such as the lumbo-pelvic-hip muscles (Aminaka et al. 2011, Biabanimoghadam et al. 2016, Cowan et al. 2009). Several studies have found that patients with PFPS have impaired lumbo-pelvic-hip muscle function as a result or cause of PFPS, a finding supported by Motealleh et al. (Motealleh et al. 2015), Cowan et al. (Cowan et al. 2009), Robinson and Nee (Robinson & Nee 2007), Piva et al. (Piva et al. 2005), and Ireland et al. (Ireland et al. 2003). One possible cause of impaired lumbo-pelvic-hip muscle function is the formation of myofascial trigger points (MTrPs). These are described as hyperirritable spots in the fascia surrounding skeletal muscles, that elicit local pain and refer it to another region (Kanner 2003). Trigger points may result from or be exacerbated by trauma, overuse, mechanical overload, postural faults, or psychological stress (Jafri 2014). The presence of MTrPs in muscles results in impaired motor function and motor control (Lucas et al. 2010), as well as decreased muscle tone and muscle strength (Kanner 2003). Therefore, the presence of MTrPs in lumbo-pelvic-hip muscles may impair proximal stability via
2
the mechanisms noted above. Proximal instability, in turn, can lead to impaired muscle function in the lower extremities and consequent exacerbation of PFPS (Brumitt 2009). Thus, the evidence appears to support that therapists should target the lumbo-pelvic-hip region in the treatment of PFPS (Ellenbecker 2000). However, due to the large number of lower extremity and lumbar muscles, and the high frequency of MTrPs in these regions, not all MTrPs may need to be treated during therapy. To the best of our knowledge, there is no evidence regarding the most common MTrPs located in the lumbo-pelvic-hip muscles. Evidence of the relative prevalences of MTrPs in different locations would help therapists to target them during treatment, yet most available studies evaluated the prevalence of MTrPs in hip muscles. Therefore, the present study aimed to compare the prevalence of MTrPs in different lumbopelvic-hip muscles in patients with PFPS compared to healthy persons. METHODS Sample size In this retrospective cross-sectional study, 30 patients with PFPS and 30 healthy persons between 18 and 40 years old were recruited. Sample size was estimated with a sample size calculator (α=0.05, 1-β=0.9, d=0.2) (Roach et al. 2013). Patients with PFPS were recruited among randomly selected physiotherapy and rehabilitation clinics, and healthy participants were selected among staff members and students at Shiraz University of Medical Sciences. Participants in both groups were matched for age, height and weight. Inclusion criteria •
Women 18 to 40 years old with anterior knee pain (Hudson & Darthuy 2009)
•
Pain in the anterior knee during running, jumping, squatting, climbing stairs or sitting for
a prolonged period with bent knees (Cowan et al. 2002)
3
•
Pain in the retropatellar region (Cichanowski et al. 2007)
•
Unexpected onset of symptoms, which lasted for over 3 months (chronic pain)
•
Positive patellar grind test
•
Functional Index Questionnaire score of 11 or higher (Aminaka et al. 2011)
•
Pain visual analog scale (VAS) score of at least 3 out of 10 during the previous30 days
(Magee 2014) •
Signature provided on the written informed consent form
Exclusion criteria •
History of thigh, knee or ankle joint surgery
•
History of patellar dislocation
•
History of meniscus injury
•
History of ligament instability
•
Pain in the patellar tendon
•
Articular cartilage lesion
•
Myofascial pain syndrome
•
Use of atorvastatin or any other drugs that led to muscle pain
•
Joint inflammation within the previous year
•
Pregnancy or breastfeeding
•
Neuromuscular or central nervous system diseases
•
Metabolic diseases such as diabetes or rheumatoid arthritis
•
Professional athletes
Procedures
4
The inclusion and exclusion criteria were initially evaluated by the first examiner. Then participants were informed of the study objectives and asked to provide their consent in writing to take part. This study was approved by the local Ethics Committee of Shiraz University of Medical Sciences (Ethics code: IR.SUMS.REC.1394.S730). The prevalence and pressure pain threshold of MTrPs in the two groups were assessed by a second examiner, who was blinded to the study protocols. First, the most common locations of MTrPs in each muscle under investigation was marked with a marker. Then the presence of MTrPs was identified by palpation, according to the criteria proposed by Travell and Simons (Simons et al. 1999), which include 1) taut band within a skeletal muscle, 2) tenderness in taut bands, 3) a local twitch response on palpation of the taut band, 4) referred pain elicited on palpation of the taut band, and 5) spontaneous pain in the immediately surrounding tissues and/or distant sites in specific referred pain patterns. The presence of at least one perceived painful spot in a taut band was sufficient for the identification of MTrPs in this study (Simons et al. 1999). Muscles in the lumbar region Muscles examined in the lumbar region were the internal oblique, erector spinae and quadratus lumborum. Muscles in the pelvic region Muscles examined in the pelvic region were the gluteus maximus, gluteus medius, gluteus minimus and piriformis. Muscles in the hip region Muscles examined in the hip region were the quadriceps, hamstring, tensor fascia lata, adductor and sartorius. Pressure pain threshold detection
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After detecting the MTrPs, the pressure pain threshold (recorded as the force in kg/cm2) was measured in each muscle with a pressure algometer (FDIX25 Digital Force Gauge, Greenwich, CT, USA). The algometer was placed on the skin over the muscle and pressure was applied at an angle of 90 degrees flexion (Tsai et al. 2000). The participants were asked to report pain as soon as they felt it. Measurements were repeated twice at 30-seconds intervals between trials, and the mean trial pressure pain was calculated and recorded as the final pressure pain threshold (Aparicio et al. 2013). Statistical methods The Kolmogorov–Smirnov test showed that the data were distributed normally. The chi-squared test was used to compare the prevalence of MTrPs between the two groups, and independent ttests were used to compare pressure pain thresholds and demographic characteristics between the two groups. P-values ≤0.05 were considered statistically significant. RESULTS Demographic characteristics The findings showed no significant differences in age, height or weight between the two groups (Table 1). PLACE TABLE 1 HERE. MTrPs in lumbar muscles The prevalence of MTrPs in lumbar muscles was significantly higher in patients with PFPS compared to healthy participants (Table 2). The pressure pain threshold of MTrPs in muscles of the lumbar region was significantly lower in patients with PFPS than in healthy participants (Table3). PLACE TABLE 2 AND 3 HERE.
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MTrPs in pelvic muscles The prevalence of MTrPs in the gluteus maximus, gluteus medius and piriformis muscles was significantly higher in the PFPS group compared to healthy persons. However, there was no significant difference between groups in the prevalence of MTrPs in the gluteus minimus (Table4). The pressure pain threshold of MTrPs in pelvic muscles was significantly lower in patients with PFPS compared to healthy participants (Table 5). PLACE TABLE 4 AND 5 HERE. MTrPs in hip muscles The prevalence of MTrPs in the tensor fascia lata, sartorius, rectus femoris, vastus medialis, vastus lateralis, biceps femoris, semitendinosus and semimembranosus muscles was significantly higher in patients with PFPS than in the healthy group. However, there was no significant difference between groups in the prevalence of MTrPs in adductor muscles (Table 6). The pressure pain threshold of MTrPs in muscles of the hip region was significantly lower in patients with PFPS compared to healthy participants (Table 7). PLACE TABLE 6 AND 7 HERE. DISCUSSION Prevalence of MTrPs and pressure pain threshold in lumbar muscles The prevalence of MTrPs in lumbar muscles was significantly higher in patients with PFPS than healthy persons. Also, the pressure pain threshold in lumbar region muscles was significantly lower in patients with PFPS than healthy participants. The higher prevalence of MTrPs in the lumbar region in patients with PFPS might be due to the impaired function of these muscles as a result or cause of PFPS. Lumbar muscles act as eccentric stabilizers of the trunk region. Impaired proximal stability in patients with PFPS may increase the load on these muscles, and thus lead to
7
the formation of MTrPs and lowered pressure pain thresholds (Mascal et al. 2003). Many studies have proposed a direct relationship between impaired proximal stability and PFPS (Cowan et al.2009), but only Roach et al. (Roach et al. 2013) evaluated MTrPs in the quadratus lumborum muscle in patients with PFPS; they reported a higher prevalence of MTrPs in patients with PFPS compared to healthy individuals, which was in line with the findings of the present study. Prevalence of MTrPs and pressure pain threshold in pelvic muscles The results reported here show that the prevalence of MTrPs in the gluteus maximus, gluteus medius and piriformis muscles was significantly higher in patients with PFPS than in healthy persons, but there was no significant difference between groups in the prevalence of MTrPs in the gluteus minimus. In addition, the pressure pain threshold in all pelvic region muscles was significantly lower in patients with PFPS. The gluteus maximus is the main extensor muscle of the hip, and the gluteus medius is one of the main hip abductors that stabilizes the hip joint in the frontal plane. The piriformis muscle is an external rotator of the hip, acting as a tonic stabilizer of the hip joint (Simons et al. 1999). Robinson et al. found that 25% to 50% of patients with PFPS had reduced strength in the abductor, extensor and external rotator muscles. These weaknesses made patients with PFPS more likely to develop MTrPs, with a lower pressure pain threshold in these muscles compared to healthy persons (Robinson & Nee 2007). Rouch et al. found that the prevalence of MTrPs in the gluteus medius was significantly higher in patients with PFPS than in healthy people, which was in line with the results reported in the present study (Roach et al. 2013). Given that the gluteus minimus is not a main extensor, abductor or rotator of the hip, weakness and consequently trigger point formation may be less frequent in this muscle in patients with PFPS.
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This may explain why we found no difference in the prevalence of trigger points in this muscle between patients with PFPS and healthy persons. Prevalence of MTrPs and pressure pain threshold in hip muscles The prevalence of MTrPs in hip muscles, except for the adductor muscles, was significantly higher in patients with PFPS than in healthy participants. In addition, the pressure pain threshold in hip region muscles was significantly lower in patients with PFPS compared to healthy persons. The present findings showed that all participants with PFPS had MTrPs in the quadriceps muscle bellies, in consonance with earlier results reported by Smith (Smith 2012) and Daly (Daly 2005). Among the quadriceps muscles, MTrPs were most prevalent in the vastus lateralis, which may reflect the greater likelihood of MTrP formation in the fibers of this muscle, as reported previously (Smith 2012). This result is also consistent with an earlier study by Dippenaar (Dippenaar 2003). However, in contrast to the present results, Smith found that among quadriceps muscles, MTrPs were most prevalent in the vastus medialis (Smith 2012). In the present study the prevalence of MTrPs in the rectus femoris was 76.7%, a figure very similar to the 76.3% prevalence of MTrPs reported in an earlier study of patients with PFPS (Dippenaar 2003). In contrast, Smith (Smith 2012) found a prevalence of MTrPs in the rectus femoris of only 8.8%. This difference between studies may be the result of gender differences, given that the majority of participants in the study by Smith were males, whereas all participants in the present study were females. It has been reported that females exhibit higher quadriceps activity compared to males during the same tasks (Chappell et al. 2007, Krishnan et al. 2008). The higher quadriceps activity may cause a greater load on the rectus femoris muscle, which may account for the higher prevalence of trigger points in the rectus femoris in our study (with female participants) compared to Smith’s study (with male participants). In addition, differences in
9
anatomical, hormonal or neuromuscular factors between males and females (Mendiguchia et al. 2011) may explain the different prevalences of trigger points in the rectus femoris in the present study and Smith’s study. The prevalence of MTrPs in hamstring muscles was 96.6% in the present study, a figure similar to the 86.3% prevalence found by Smith (Smith 2012). The higher prevalence of MTrPs in hamstring muscles in patients with PFPS compared to healthy persons may be due to the greater likelihood of hamstring muscle shortness in patients with PFPS than in healthy individuals (White et al. 2009). Moreover, reduced lateral patellar tracking in patients with PFPF increases the likelihood of MTrP development in the hamstring muscles compared to healthy persons (White et al. 2009). According to the present results, the prevalence of MTrPs in the tensor fascia lata was significantly higher in patients with PFPS than in healthy persons. No previous studies have specifically focused on the prevalence of MTrPs in this muscle in patients with PFPS. The sartorius is an abductor muscle that functions as an important flexor and external rotator of the hip joint (Simons et al. 1999). Weakened abduction and rotation strength in patients with PFPS may lead to increased loads on this muscle, which in turn may result in a higher prevalence of MTrPs and lower pressure pain threshold compared to healthy individuals (Page et al. 2010). The present results showed a high prevalence of MTrPs in adductor muscles in both groups: 96.7% in patients with PFPS and 83.3% in healthy persons. This finding is consistent with the high prevalence of MTrPs (64%) in adductor muscles that was reported in a previous study of patients with PFPS (Smith 2012). The higher prevalence of MTrPs in adductor muscles
10
in both groups may be due to the location of this muscle in a sensitive area of the body, especially in women (Smith 2012). LIMITATIONS Because psychological and emotional stress may activate MTrPs (Dommerholt et al. 2006), it would have been informative to assess emotional parameters in our participants at baseline. However, the short assessment period meant that we were not able to assess these factors. In addition, because of the high number of lumbo-pelvic-hip muscles we did not evaluate trigger points in all of the muscles in this region. Furthermore, because of differences between males and females in anatomical, hormonal and neuromuscular factors (Mendiguchia et al. 2011), the prevalence of trigger points may differ between men and women. Accordingly, the results of the present study are not generalizable to males. Additional research is required to compare the prevalence of trigger points between males and females with PFPS, and to determine the prevalence of trigger points in other muscles of the lumbo-pelvic-hip region. Another factor that merits further research is emotional status and how it might affect the response to treatment. Future studies should also compare the prevalence of MTrPs on both sides in patients with PFPS and healthy people. CONCLUSION The prevalence of MTrPs was higher, and pressure pain threshold in the lumbo-pelvic-hip muscles was lower, in patients with PFPS than in healthy participants. CLINICAL RELEVANCE •
Therapists can target trigger points in lumbo-pelvic-hip muscles during treatment in patients with PFPS.
11
•
Given the absence of significant differences in trigger points in the gluteus minimus and adductor muscles between people with PFPS and healthy people, therapists may target the trigger points in these two muscles as a second priority compared to other lumbopelvic-hip muscles that were investigated in this study.
ACKNOWLEDGEMENTS This work was supported by Shiraz University of Medical Sciences. The authors wish to thank Mr. H. Argasi at the Research Consultation Center of Shiraz University of Medical Sciences for his invaluable assistance in editing this manuscript, and K. Shashok (AuthorAID in the Eastern Mediterranean) for improving the use of English in the manuscript.
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Daly G 2005 The Relationship Between Myofascial Trigger Points, Total Work and Other Recorded Measurements of the Vastus Lateralis and Vastus Medialis, in Long-Distance Runners with Patellofermoral Pain Syndrome (thesis). M. Tech: Chiropractic, Durban University of Technology, Durban, South Africa. Dippenaar D 2003 The association between myofascial trigger points of the Quadriceps femoris muscle group and the clinical presentation of patellofemoral pain syndrome using a piloted patellofemoral pain severity rating scale (thesis). M. Tech: Chiropractic, Durban University of Technology, Durban, South Africa. Dommerholt J, Bron C, Franssen J 2006 Myofascial trigger points: an evidence-informed review, Journal of Manual & Manipulative Therapy. 14, 203-221. Ellenbecker T.S 2000 Knee Ligament Rehabilitation, Churchill Livingstone, Edinburgh. Fagan V,Delahunt E 2008 Patellofemoral pain syndrome: a review of the associated neuromuscular deficits and current treatment options, British Journal of Sports Medicine. 42, 10: 789-95. Hudson Z, Darthuy E 2009 Iliotibial band tightness and patellofemoral pain syndrome: a casecontrol study, Manual Therapy. 14, 2: 147-51. Ireland M.L, Willson J.D, Ballantyne B.T,Davis I.M 2003 Hip strength in females with and without patellofemoral pain, Journal of Orthopaedic &Sports Physical Therapy. 33, 11: 671-6. Jafri MS 2014 Mechanisms of myofascial pain, International Scholarly Research Notices. 2014. Kanner R 2003 Pain Management Secrets, Hanley &Belfus,Philadelphia. Krishnan C, Huston K, Amendola A, Williams G. N 2008 Quadriceps and hamstrings muscle control in athletic males and females, Journal of Orthopaedic Research. 26, 800-808.
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Lucas K.R, Rich P.A, Polus B.I 2010 Muscle activation patterns in the scapular positioning muscles during loaded scapular plane elevation: the effects of latent myofascial trigger points, Clinical Biomechanics. 25, 8: 765-70. Magee D.J 2014 Orthopedic Physical Assessment, Elsevier Health Sciences. Mascal C.L, Landel R,Powers C 2003 Management of patellofemoral pain targeting hip, pelvis, and trunk muscle function: 2 case reports, Journal of Orthopaedic & Sports Physical Therapy. 33, 11: 647-60. Mendiguchia J, Ford K. R, Quatman C. E, Alentorn-Geli E, Hewett T. E 2011 Sex differences in proximal control of the knee joint, Sports Medicine. 41, 541-557. Motealleh A, Maroufi N, Sarrafzadeh J, Sanjari M.A, Salehi N 2015 Comparative Evaluation of Core and Knee Extensor Mechanism Muscle Activation Patterns in a Stair Stepping Task in Healthy Controls and Patellofemoral Pain Patients, Journal of Rehabilitation Sciences and Research.1,4: 84-91. Nijs J, Van Geel C, Van de Velde B 2006 Diagnostic value of five clinical tests in patellofemoral pain syndrome, Manual Therapy. 11, 1: 69-77. O'Sullivan S.P,Popelas C.A 2005 Activation of vastus medialis obliquus among individuals with patellofemoral pain syndrome, The Journal of Strength & Conditioning Research. 19, 2: 302-4. Page P, Frank C,Lardner R 2010 Assessment and Treatment of Muscle Imbalance: The Janda Approach, Human Kinetics,Champaign. Piva S.R, Goodnite E.A,Childs J.D 2005 Strength around the hip and flexibility of soft tissues in individuals with and without patellofemoral pain syndrome, Journal of Orthopaedic &Sports Physical Therapy.35, 12: 793-801.
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Roach S, Sorenson E, Headley B,San Juan J.G 2013 Prevalence of myofascial trigger points in the hip in patellofemoral pain, Archives of Physical Medicine and Rehabilitation.94, 3: 522-6. Robinson R.L,Nee R.J 2007 Analysis of hip strength in females seeking physical therapy treatment for unilateral patellofemoral pain syndrome, Journal of Orthopedic &Sports Physical Therapy.37, 5: 232-8. Simons D.G, Travell J.G,Simons L.S 1999 Travell & Simons Myofascial Pain and Dysfunction: Upper Half of Body, vol. 1, Lippincott Williams & Wilkins,Philadelphia. Smith K.L.F 2012 The Role of and Relationship Between Hamstring and Quadriceps Muscle Myofascial Trigger Points in Patients with Patellofemoral Pain Syndrome(thesis). M. Tech: Chiropractic, Durban University of Technology, Durban, South Africa. Souza R.B 2008 The Influence of Hip and Femur Kinematics on Patellofemoral Joint Dysfunction, ProQuest,Ann Arbor. Tsai W.C, Wang C.L, Tang, F.T, Hsu T.C, Hsu K.H, Wong M.K 2000 Treatment of proximal plantar fasciitis with ultrasound-guided steroid injection, Archives of Physical Medicine and Rehabilitation. 81, 10: 1416-21. White L.C, Dolphin P, Dixon J 2009 Hamstring length in patellofemoral pain syndrome, Physiotherapy. 95, 1: 24-8.
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TABLES Table 1. Demographic characteristics of participants in the PFPS and healthy groups
Items
PFPS group
Healthy group
P value
Age (years)
22.1 ± 1.5
22.1 ± 1.1
0.926
Height (cm)
162.0 ± 7.3
164.8 ± 6.2
0.109
Weight (kg)
57.8 ± 11.0
56.4 ± 10.1
0.611
1
Table 2. Prevalence of lumbar MTrPs in the two groups Muscle
Prevalence
PFPS group
Healthy group
P value
IO
Number
24
10
<0.001*
Percent
80.0%
33.0%
Number
21
8
Percent
70.0%
26.7%
Number
23
8
Percent
76.7%
26.7%
QL
ES
0.001*
<0.001*
Abbreviations: MTrPs: Myofascial trigger points, IO: Internal oblique, QL: Quadratus lumborum, ES: Erector spinae *Significant difference
2
Table 3. Pain threshold in lumbar MTrPs in the two groups Muscle
PFPS group
Healthy group
P value
IO
1.19±0.64
1.97±0.78
<0.001*
QL
1.39±0.86
2.92±1.46
<0.001*
ES
1.31±0.88
3.19±1.46
<0.001*
Abbreviations: MTrPs: Myofascial trigger points, IO: Internal oblique, QL: Quadratus lumborum, ES: Erector spinae *Significant difference
3
Table 4. Prevalence of pelvic MTrPs in the two groups Muscle
Prevalence
PFPS group
Healthy group
P value
GMax
Number
18
4
0.006*
Percent
60.0%
13.3%
Number
27
17
Percent
90.0%
56.7%
Number
28
23
Percent
93.3%
76.7%
Number
23
13
Percent
76.7%
43.3%
GMed
GMin
Piriformis
0.004*
0.071
0.001*
Abbreviations: MTrPs: Myofascial trigger points, GMax: Gluteus maximus, GMed: Gluteus medius, GMin: Gluteus minimus *Significant difference
4
Table 5. Pain threshold in pelvic MTrPs in the two groups Muscle
PFPS group
Healthy group
P value
1st MTrPs in GMax
1.81±1.19
3.59±1.88
<0.001*
GMed
1.17±0.59
2.61±1.20
<0.001*
GMin
1.10±0.70
1.62±0.62
0.003*
1st MTrPs in piriformis
1.52±1.02
3.17±1.41
<0.001*
Abbreviations: MTrPs: Myofascial trigger points, GMax: Gluteus maximus, GMed: Gluteus medius, GMin: Gluteus minimus *Significant difference
5
Table 6. Prevalence of hip MTrPs in the two groups Muscle
Prevalence
PFPS group
Healthy group
P value
TFL
Number
19
7
0.002*
Percent
63.3%
23.3%
Number
23
12
Percent
76.7%
40.0%
Number
17
9
Percent
56.7%
30.0%
Number
20
4
Percent
66.7%
13.3%
Number
23
6
Percent
76.7%
20.0%
Number
27
16
Percent
90.0%
53.3%
Number
26
15
Percent
86.7%
50.0%
RF
Sartorius
VM
VL
ST&SM
BF
6
0.004*
0.030*
<0.001*
<0.001*
0.002*
0.002*
Add
Number
29
25
Percent
96.7%
83.3%
0.085
Abbreviations: MTrPs: Myofascial trigger points, TFL: Tensor fascia lata, RF: Rectus femoris, VM: Vastus medialis, VL: Vastus lateralis, ST&SM: Semimembranosus and semitendinosus, BF: Biceps femoris, Add: Adductor *Significant difference
7
Table 7. Pain tolerance in hip MTrPs in the two groups Muscle
PFPS group
Healthy group
P value
TFL
2.17±1.64
3.69±1.53
<0.001*
RF
1.86±1.25
3.10±1.37
0.001*
Sartorius
2.32±1.59
3.61±1.56
0.003*
VM
1.56±1.00
3.35±0.91
<0.001*
VL
1.48±0.94
3.36±1.41
<0.001*
ST&SM
0.85±0.62
2.46±1.37
<0.001*
BF
1.16±0.64
2.78±1.66
<0.001*
Add
0.77±0.23
1.28±0.47
<0.001*
Abbreviations: MTrPs: Myofascial trigger points, TFL: Tensor fascia lata, RF: Rectus femoris, VM: Vastus medialis, VL: Vastus lateralis, ST&SM: Semimembranosus and semitendinosus, BF: Biceps femoris, Add: Adductor
8