Abstract
Introduction:
Patellofemoral pain syndrome (PFPS) is characterized by anterior knee pain, which may limit the performance of functional activities. The influence of hip joint motion on the development of this syndrome has already been documented in the literature. In this regard, studies have investigated the effectiveness of hip muscle strengthening in patients with PFPS.
Objectives:
The aims of this systematic review were (1) to summarize the literature related to the effects of hip muscle strengthening on pain intensity, muscle strength, and function in individuals with PFPS and (2) to evaluate the methodological quality of the selected studies.
Method:
A search for randomized controlled clinical trials was conducted using the following databases: Google Scholar, MEDLINE, PEDro, LILACS, and SciELO. The selected studies had to distinguish the effects of hip muscle strengthening in a group of patients with PFPS, as compared to non-intervention or other kinds of intervention, and had to investigate the following outcomes: pain, muscle strength, and function. The methodological quality of the selected studies was analyzed by means of the PEDro scale.
Results:
Seven studies were selected. These studies demonstrated that hip muscle strengthening was effective in reducing pain. However, the studies disagreed regarding the treatments' ability to improve muscle strength. Improvement in functional capabilities after hip muscle strengthening was found in five studies.
Conclusion:
Hip muscle strengthening is effective in reducing the intensity of pain and improving functional capabilities in patients with PFPS, despite the lack of evidence for its ability to increase muscle strength.
patellofemoral pain syndrome; muscle strengthening; pain; function; hip; rehabilitation
Introduction
Patellofemoral pain syndrome (PFPS) is characterized by retro or peripatellar pain,
mainly during weight-bearing activities, such as ascending and descending
stairs11 Powers CM, Heino JG, Rao S, Perry J. The influence of patellofemoral
pain on lower limb loading during gait. Clin Biomech (Bristol, Avon).
1999;14(10):722-8. http://dx.doi.org/10.1016/S0268-0033(99)00019-4 .
PMid:10545627
http://dx.doi.org/10.1016/S0268-0033(99)...
. In addition to pain, the
clinical presentation of this syndrome includes muscular weakness and altered lower
limb biomechanics22 César CM, Alves FC, Gonçalves LTN, Ocarino J, Lanna P. Avaliação da
progressão no desempenho e capacidade funcional em indivíduos em reabilitação
devido à síndrome patelofemoral. Fisioter Bras. 2007;8(1):21-4.. PFPS is considered the
most common overuse injury of the lower limb and is more prevalent in physically
active individuals33 Powers CM. The influence of altered lower-extremity kinematics on
patellofemoral joint dysfunction: a theoretical perspective. J Orthop Sports
Phys Ther. 2003;33(11):639-46. http://dx.doi.org/10.2519/jospt.2003.33.11.639 .
PMid:14669959
http://dx.doi.org/10.2519/jospt.2003.33....
,
44 Davis IS, Powers C. Patellofemoral pain syndrome: proximal, distal,
and local factors, an international retreat, April 30-May 2, 2009, Fells Point,
Baltimore, MD. J Orthop Sports Phys Ther. 2010;40(3):A1-16.
http://dx.doi.org/10.2519/jospt.2010.0302 . PMid:20195028
http://dx.doi.org/10.2519/jospt.2010.030...
. Physiotherapy is recommended for reducing
the pain intensity and functional limitations associated with PFPS55 Harvie D, O'Leary T, Kumar S. A systematic review of randomized
controlled trials on exercise parameters in the treatment of patellofemoral
pain: what works?. J Multidiscip Healthc. 2011;4:383-92.
PMid:22135495.. Traditional treatments aim at improving
patellar alignment and strengthening the knee muscles66 Garcia FR, Azevedo FM, Alves N, Carvalho AC, Padovani CR, Negrao
Filho RF. Effects of electrical stimulation of vastus medialis obliquus muscle
in patients with patellofemoral pain syndrome: an electromyographic analysis.
Rev Bras Fisioter. 2010;14(6):477-82.
http://dx.doi.org/10.1590/S1413-35552010000600005 . PMid:
21340241
http://dx.doi.org/10.1590/S1413-35552010...
. However, several studies highlight the influence of other joints,
such as hip, in the development of this syndrome.
In recent years, hip muscle strengthening has been proposed as a proper treatment for
patients with PFPS. The rationale for this intervention is supported by the
theoretical background hypothesizing that excessive hip motion, especially in
frontal and transverse planes, places stress on the patellofemoral joint33 Powers CM. The influence of altered lower-extremity kinematics on
patellofemoral joint dysfunction: a theoretical perspective. J Orthop Sports
Phys Ther. 2003;33(11):639-46. http://dx.doi.org/10.2519/jospt.2003.33.11.639 .
PMid:14669959
http://dx.doi.org/10.2519/jospt.2003.33....
. This excessive hip motion may be related to
the weakness of muscles surrounding the hip joint77 Ireland ML, Willson JD, Ballantyne BT, Davis IM. Hip strength in
females with and without patellofemoral pain. J Orthop Sports Phys Ther.
2003;33(11):671-6. http://dx.doi.org/10.2519/jospt.2003.33.11.671 .
PMid:14669962
http://dx.doi.org/10.2519/jospt.2003.33....
8 Robinson RL, Nee RJ. Analysis of hip strength in females seeking
physical therapy treatment for unilateral patellofemoral pain syndrome. J Orthop
Sports Phys Ther. 2007;37(5):232-8. http://dx.doi.org/10.2519/jospt.2007.2439.
PMid:17549951
http://dx.doi.org/10.2519/jospt.2007.243...
9 Cichanowski HR, Schmitt JS, Johnson RJ, Niemuth PE. Hip strength in
collegiate female athletes with patellofemoral pain. Med Sci Sports Exerc.
2007;39(8):1227-32. http://dx.doi.org/10.1249/mss.0b013e3180601109 .
PMid:17762354
http://dx.doi.org/10.1249/mss.0b013e3180...
10 Bolgla LA, Malone TR, Umberger BR, Uhl TL. Hip strength and hip and
knee kinematics during stair descent in females with and without patellofemoral
pain syndrome. J Orthop Sports Phys Ther. 2008;38(1):12-8.
http://dx.doi.org/10.2519/jospt.2008.2462 . PMid:18349475
http://dx.doi.org/10.2519/jospt.2008.246...
-
1111 Barton CJ, Lack S, Malliaras P, Morrissey D. Gluteal muscle activity
and patellofemoral pain syndrome: a systematic review. Br J Sports Med.
2013;47(4):207-14. http://dx.doi.org/10.1136/bjsports-2012-090953 .
PMid:22945929
http://dx.doi.org/10.1136/bjsports-2012-...
. In this case, patients with PFPS could
benefit from hip muscle strengthening, since this intervention may reduce excessive
hip motion and, as a consequence, excessive patellofemoral joint stress. As a
result, hip muscle strengthening has been proposed as an effective treatment to
reduce pain and improve function in PFPS patients.
In 2003, Mascal et al.1212 Mascal CL, Landel R, Powers C. Management of patellofemoral pain
targeting hip, pelvis, and trunk muscle function: 2 case reports. J Orthop
Sports Phys Ther. 2003;33(11):647-60.
http://dx.doi.org/10.2519/jospt.2003.33.11.647 . PMid:14669960
http://dx.doi.org/10.2519/jospt.2003.33....
suggested an
intervention for PFPS that included strengthening of hip muscles and showed clinical
improvement in two patients. After this initial study, other studies were performed
to investigate the effects of hip muscle strengthening on the improvement of
patients with PFPS1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises
with or without additional hip strengthening exercises in management of
patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil
Med. 2013;49(5):687-98. PMid:23820880
14 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
15 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
16 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
17 Razeghi M, Etemadi Y, Sh T, Ghaem H. Could hip and knee muscle
strengthening alter the pain intensity in patellofemoral pain syndrome? Iranian
Red Crescent Medical Journal. 2010;12(2):104-10.
18 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
-
1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
. However, results of these studies were
equivocal and only a few were randomized controlled trials (RCT). RCT is considered
the best study design to evaluate the effects of an intervention since the
randomization protects against allocation bias2020 Kunz R, Oxman AD. The unpredictability paradox: review of empirical
comparisons of randomised and non-randomised clinical trials. BMJ.
1998;317(7167):1185-90. http://dx.doi.org/10.1136/bmj.317.7167.1185.
PMid:9794851
http://dx.doi.org/10.1136/bmj.317.7167.1...
. In order to combine the evidence provided by these studies and
reveal the true contribution of hip muscle strengthening to the treatment of
patients with PFPS, a systematic review of this literature is needed. Thus, the aims
of this systematic review were (1) to summarize the literature related to the
effects of hip muscle strengthening on pain intensity, muscle strength, and function
in individuals with PFPS and (2) to evaluate the methodological quality of the
selected studies. The results of this review may help researchers to plan future
studies since they can refine hypotheses, recognize and avoid pitfalls of previous
studies, and estimate sample sizes2121 Mulrow CD. Rationale for systematic reviews. BMJ.
1994;309(6954):597-9. http://dx.doi.org/10.1136/bmj.309.6954.597 .
PMid:8086953
http://dx.doi.org/10.1136/bmj.309.6954.5...
.
Furthermore, this review may contribute to integrate existing knowledge about the
effects of hip muscle strengthening on patellofemoral pain syndrome and provide data
for clinical decision making2121 Mulrow CD. Rationale for systematic reviews. BMJ.
1994;309(6954):597-9. http://dx.doi.org/10.1136/bmj.309.6954.597 .
PMid:8086953
http://dx.doi.org/10.1136/bmj.309.6954.5...
.
Method
A search was conducted among studies published in English, Portuguese, and Spanish using the databases Google Scholar, MEDLINE, PEDro, LILACS, and SciELO. The following keywords were used: patellofemoral pain syndrome, hip, strengthening, physical therapy, rehabilitation, and their correlates in Portuguese and Spanish. Furthermore, the reference lists of the selected studies were also investigated. There was no restriction as to the publication dates of the articles; the search was conducted between August, 2013 and September, 2014.
Only randomized controlled clinical trials (RCT) that included volunteers with PFPS were selected. In order to be included in the final review, the studies had to allow discrimination of the effects of hip muscle strengthening in a group of patients with PFPS, as compared to non-intervention or another kind of intervention. In addition, the articles had to investigate at least one of the following outcomes: pain, muscle strength, and function. In this review, the experimental group was identified as that in which the intervention activities contained at least hip muscle strengthening. On the other hand, the control group was the one in which no intervention or any other type of treatment was applied.
In order to identify and characterize the variables applicable to the present study,
the following information was extracted from the selected studies: type and
characteristics of the intervention, applicable variables, and evaluation
instruments used. Furthermore, the methodological quality of the studies was
analyzed based on the score in the Physiotherapy Evidence Database (PEDro) scale
provided by PEDro database. If the selected study was not scored in this database,
the authors would rank using the Portuguese (Brazilian) version of the scale2222 Shiwa SR, Costa LOP, Moser ADL, Aguiar IC, Oliveira LVF. PEDro: a
base de dados de evidências em fisioterapia. Fisioter Mov. 2011;24(3):523-33.
http://dx.doi.org/10.1590/S0103-51502011000300017.
http://dx.doi.org/10.1590/S0103-51502011...
. In that case, the analysis would be
performed independently by two evaluators and disagreements resolved by discussion
and consensus.
The quantitative synthesis of the results of the studies was shown using forest plots. Since the variables were treated as continuous by the studies, the intervention effect was analyzed using the mean difference between groups after intervention, with a 95% confidence interval, calculated using Cochrane Collaboration's RevMan 5.2 software.
Results
The search strategy yielded 2381 studies (Google Scholar = 1904, MEDLINE = 299, PEDro = 100, LILACS = 34, SciELO = 44), of which 2265 were excluded after reading the title and 20 were duplicates. Of the remaining 96 studies identified for possible inclusion, 78 were excluded after reading the abstracts. Thus, 18 studies were selected. Of these 18 studies, 12 were excluded after full reading, since they did not apply hip muscle strengthening intervention or did not investigate at least one of the clinical outcomes considered in this review. Additionally, one study was included following a search of the reference lists of the selected studies. Thus, seven studies were included in this review. Table 1 demonstrates the details of the intervention of the selected studies, as well as the clinical outcomes investigated therein. All selected studies were scored in the PEDro database and the results for each item are shown in Table 2.
Means and standard deviations of pain, function, and muscle strength after the intervention are shown according to the group (experimental and control) for each analyzed study in Tables 3, 4, and 5. Furthermore, these tables present the sample size in each group and the 95% confidence interval of the mean difference between groups, which is also shown in the Forest plots.
One of the selected studies compared the hip muscle strengthening intervention group
(i.e., experimental) against a control group that used Omega-3 and calcium for eight
weeks as a placebo1515 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
. Only the experimental
group showed reduction in pain intensity and improvement in function and in hip
lateral rotator and abductor strength1515 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
(Tables 3, 4, and 5). Another
study compared an intervention that included hip muscle strengthening against an
intervention that included knee extensor strengthening1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
. After this intervention was applied for four weeks,
functional exercises were added for another four weeks in both groups1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
. The groups were reassessed at the end of
the full eight weeks of intervention and again after four more weeks without
intervention1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
. The experimental group
had less pain after four weeks than the control group1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
(Table 3). The groups did not
differ in relation to function in any of the assessment moments1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
(Table 5). In
addition, the experimental group showed greater muscular strength than the control
group only in hip lateral rotators1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
(Table 4) and this difference was found only
after the 8th week (Table 4).
Four studies1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
,
1515 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
,
1717 Razeghi M, Etemadi Y, Sh T, Ghaem H. Could hip and knee muscle
strengthening alter the pain intensity in patellofemoral pain syndrome? Iranian
Red Crescent Medical Journal. 2010;12(2):104-10.
,
1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
compared an intervention that included hip
muscle strengthening (experimental group) against another intervention that included
only knee muscle strengthening (control group). These four studies also assessed
pain intensity in different contexts. Two studies1717 Razeghi M, Etemadi Y, Sh T, Ghaem H. Could hip and knee muscle
strengthening alter the pain intensity in patellofemoral pain syndrome? Iranian
Red Crescent Medical Journal. 2010;12(2):104-10.
,
1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
assessed daily pain intensity and both
identified greater improvement in the experimental group (Table 3). Three studies investigated pain intensity when
ascending and descending stairs1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
,
1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
,
1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
. Two studies identified1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
,
1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
greater reduction in pain intensity when
ascending stairs in the experimental group, while the other study1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
did not identify differences between groups
(Table 3). One study1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
identified greater reduction in pain when
descending stairs while the other two studies1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
,
1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
did not identify differences between
groups (Table 3). One study1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
also investigated pain intensity when
squatting and sitting for long periods and found that the experimental group
reported less pain intensity only during the squatting task (Table 3). In addition, this study1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
found that the experimental group presented less intensity
of the worst experienced pain compared to the control group (Table 3).
Two studies1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
,
1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
investigated function and one study1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
investigated eccentric muscle strength by
comparing an intervention that included hip muscle strengthening to an intervention
that included only knee muscle strengthening. Fukuda et al.1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
observed no differences between groups when they used three
tests to assess function (unilateral jump test, Lower Extremity Functional
Scale-LEFS, and Anterior Knee Pain Scale-AKPS) (Table 5). In another study, Fukuda et al.1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
observed that the experimental group had greater functional capacity
when compared to the control group, when they used these same three tests three,
six, and twelve months after intervention (Table
5). The study that assessed eccentric knee extension strength1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
did not identify differences between the
groups (Table 4).
Fukuda et al.1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
compared an intervention that
included hip muscle strengthening against no intervention. This study showed that
after four weeks of intervention, the experimental group presented a reduction in
pain intensity when ascending and descending stairs, as well as improved function
when compared to the control group1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
(Tables 3 and 5). No difference was observed between the groups in the unilateral jump
test1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
(Table 5).
One study1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises with or without additional hip strengthening exercises in management of patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil Med. 2013;49(5):687-98. PMid:23820880 compared a group that was submitted to closed kinetic chain (CKC) exercises and hip muscle strengthening (experimental group) against a group that was submitted exclusively to CKC exercises (control group). There were no differences between the groups related to pain intensity, hip muscle strength, and function after the intervention (Tables 3, 4, and 5).
Discussion
This systematic review showed that the majority of selected studies indicate that hip muscle strengthening is effective for reducing pain and improving function in individuals with PFPS. However, the studies disagreed regarding the treatments' ability to improve muscle strength. The review of the literature showed only a few studies with RCT design that compared hip muscle strengthening with other treatments. The selected studies included a variety of intervention protocols and outcome assessments making it difficult to compare the results among studies and prevented statistical grouping of the results to perform meta-analysis.
The selected studies showed good internal validity according to the PEDro scale since
they satisfied the majority of the items from 2 to 11. Items 5 and 6 were not
satisfied by any study. One point is earned for these items if there was blinding of
the subjects (Item 5) and therapists (Item 6). Both procedures are difficult to be
performed by studies that looked for the effect of physical therapy interventions
because of the nature of these interventions. Apart from these criteria, the study
of Razeghi et al.1717 Razeghi M, Etemadi Y, Sh T, Ghaem H. Could hip and knee muscle
strengthening alter the pain intensity in patellofemoral pain syndrome? Iranian
Red Crescent Medical Journal. 2010;12(2):104-10. did not score other items
related to internal validity and thus, presented the lowest score. Furthermore, the
majority of the studies were rated on the external validity criterion (Item 1). Only
one study was not awarded a point for this item because it did not describe the
source of the subjects1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
. Considering the
overall score in the PEDro scale, this review selected studies that presented good
internal and external validity.
Pain intensity was evaluated by all the studies selected for this review1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises
with or without additional hip strengthening exercises in management of
patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil
Med. 2013;49(5):687-98. PMid:23820880
14 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
15 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
16 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
17 Razeghi M, Etemadi Y, Sh T, Ghaem H. Could hip and knee muscle
strengthening alter the pain intensity in patellofemoral pain syndrome? Iranian
Red Crescent Medical Journal. 2010;12(2):104-10.
18 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
-
1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
. Some studies used different scales to
evaluate this variable, while others, despite using the same scale, asked the
participants to report the mean pain intensity in different contexts. For example,
the worst pain experienced in the previous week1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
, pain when ascending and descending stairs1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
,
1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
,
1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
, and pain while squatting or sitting for
prolonged periods1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
. Regardless of the method
of evaluation, the majority of studies showed greater reduction in pain in the
hip-strengthening group as compared to the control group. It is noteworthy that
three studies1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
,
1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
,
1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
showed pain reduction in the experimental
group, in ascending and descending stairs, indicating the positive impact of this
intervention on daily activities. Furthermore, one study1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
showed that those participants who strengthened both the hip
and knee muscles presented less pain in ascending and descending stairs one year
after treatment was discontinued when compared to those participants who
strengthened only the knee muscles. This may indicate the long-term benefits of
associating both muscle groups in the intervention. However, the investigation of
benefits after such a long period (i.e. one year) was performed by only one study.
Future studies may consider investigating the long-term effects of muscle
strengthening in patients with PFPS.
Dolak et al.1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
also showed that patients who
strengthened the hip muscles had less pain intensity four weeks after treatment,
when compared to those who strengthened only the knee muscles. However, these
authors1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
indicated that, following the
intervention with functional exercises, both groups showed reduction in pain when
compared to their initial measurements. The functional exercises included unilateral
squatting, which was shown to activate the hip muscles (gluteus medius and gluteus
maximus)2323 Boren K, Conrey C, Le Coguic J, Paprocki L, Voight M, Robinson TK.
Electromyographic analysis of gluteus medius and gluteus maximus during
rehabilitation exercises. Int J Sports Phys Ther. 2011;6(3):206-23.
PMid:22034614 .
,
2424 Felicio LR, Dias LA, Silva AP, Oliveira AS, Bevilaqua-Grossi D.
Muscular activity of patella and hip stabilizers of healthy subjects during
squat exercises. Rev Bras Fisioter. 2011;15(3):206-11. PMid:
21829984.. Thus, the improvement shown by the
control group at the end of the second phase of this study may have been influenced
by the addition of functional activities, which allowed the recruitment of hip
muscles. This conjecture is supported by the absence of differences between groups
observed by Ismail et al.1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises
with or without additional hip strengthening exercises in management of
patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil
Med. 2013;49(5):687-98. PMid:23820880, whose study had
both groups performing activities such as lateral step up, which also activates hip
muscles2121 Mulrow CD. Rationale for systematic reviews. BMJ.
1994;309(6954):597-9. http://dx.doi.org/10.1136/bmj.309.6954.597 .
PMid:8086953
http://dx.doi.org/10.1136/bmj.309.6954.5...
,
2525 Souza RB, Draper CE, Fredericson M, Powers CM. Femur rotation and
patellofemoral joint kinematics: a weight-bearing magnetic resonance imaging
analysis. J Orthop Sports Phys Ther. 2010;40(5):277-85.
http://dx.doi.org/10.2519/jospt.2010.3215 . PMid:20436239.
http://dx.doi.org/10.2519/jospt.2010.321...
. In addition, other studies which included
weight bearing activities (e.g. unilateral squatting) showed a reduction in pain
intensity in the control group when comparing the results after intervention with
baseline values1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises
with or without additional hip strengthening exercises in management of
patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil
Med. 2013;49(5):687-98. PMid:23820880
,
1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
,
1717 Razeghi M, Etemadi Y, Sh T, Ghaem H. Could hip and knee muscle
strengthening alter the pain intensity in patellofemoral pain syndrome? Iranian
Red Crescent Medical Journal. 2010;12(2):104-10.. Although the control group had a
reduction in pain compared to baseline, the experimental group showed a greater
reduction in pain compared to the control group in these studies1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
,
1717 Razeghi M, Etemadi Y, Sh T, Ghaem H. Could hip and knee muscle
strengthening alter the pain intensity in patellofemoral pain syndrome? Iranian
Red Crescent Medical Journal. 2010;12(2):104-10.. Thus, some of the results showing pain
reduction in the control group may be related to the performance of weight-bearing
activities. Future studies aiming to compare hip muscle strengthening against other
interventions should consider the demand on the hip muscles during the activities
chosen for the control group.
The effects of hip muscle strengthening on hip muscle strength were equivocal1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises
with or without additional hip strengthening exercises in management of
patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil
Med. 2013;49(5):687-98. PMid:23820880
,
1515 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
,
1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
,
1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
. One factor that may explain this result
is the number of supervised sessions by the researcher. The study that offered
supervision in all sessions showed increasing torque in both hip abductors and
lateral rotators of participants from the experimental group1515 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
. On the other hand, the study that offered supervision in
one out of three sessions per week showed the increasing torque only of hip lateral
rotators of the participants from the experimental group1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
. In addition, this study presented a 95% confidence interval
of the mean difference between groups with an inferior limit near zero (Table 4). Similarly, a study that offered one
out of four supervised sessions per week did not show any muscle strength difference
between groups1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
. Thus, one hypothesis for
further research is that a greater number of supervised sessions might improve the
quality of the performance of the activities thereby increasing muscle strength.
Another factor that may be considered during the analysis of the results of muscle
strength is the specificity of the training2626 Enoka RM. Neural adaptations with chronic physical activity. J
Biomech. 1997;30(5):447-55. http://dx.doi.org/10.1016/S0021-9290(96)00170-4 .
PMid:9109556
http://dx.doi.org/10.1016/S0021-9290(96)...
. The isometric strength test used by two studies1515 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
,
1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
did not reflect the type of muscle
strengthening that was employed in the studies. Furthermore, since the majority of
daily activities are dynamic, there has been discussion as to whether measures of
isometric strength offer information specific to the activities of interest2626 Enoka RM. Neural adaptations with chronic physical activity. J
Biomech. 1997;30(5):447-55. http://dx.doi.org/10.1016/S0021-9290(96)00170-4 .
PMid:9109556
http://dx.doi.org/10.1016/S0021-9290(96)...
. Therefore, the amount of supervised
sessions and the specificity of muscle strength training may explain the differences
between the studies.
These two factors to explain the equivocality of muscle strength results among the
studies must be accepted with caution, however. In the research of Ismail et
al.1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises
with or without additional hip strengthening exercises in management of
patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil
Med. 2013;49(5):687-98. PMid:23820880, no differences in strength were
observed between groups, even though all sessions were supervised and strength was
evaluated in both concentric and eccentric tests. A confounding factor in that
experiment may have been that both groups performed weight-bearing activities that
might have improved muscle strength in both groups, making it difficult to identify
differences between groups. The effects of hip muscle strengthening on hip muscle
strength have been questioned by a previous consensus on PFPS2727 Powers CM, Bolgla LA, Callaghan MJ, Collins N, Sheehan FT.
Patellofemoral pain: proximal, distal, and local factors, 2nd International
Research Retreat. J Orthop Sports Phys Ther. 2012;42(6):A1-54.
http://dx.doi.org/10.2519/jospt.2012.0301 . PMid:22660660
http://dx.doi.org/10.2519/jospt.2012.030...
. This consensus stated that it was necessary to better
understand whether the benefits of hip strengthening exercises are due to
improvements in hip strength or to changes in neuromuscular activity2727 Powers CM, Bolgla LA, Callaghan MJ, Collins N, Sheehan FT.
Patellofemoral pain: proximal, distal, and local factors, 2nd International
Research Retreat. J Orthop Sports Phys Ther. 2012;42(6):A1-54.
http://dx.doi.org/10.2519/jospt.2012.0301 . PMid:22660660
http://dx.doi.org/10.2519/jospt.2012.030...
. Considering the equivocal results for
muscle strengthening found by this review, future studies are still required to
answer this issue.
Functional capabilities were evaluated using questionnaires and functional activities
in five of the seven studies selected. Two studies1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
,
1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
, which used the Lower Extremity Functional
Scale (LEFS) and Anterior Knee Pain Scale (AKPS) questionnaires and the unilateral
jump test, observed that the participants from the experimental group achieved
greater improvement of function compared to the control group. Furthermore, one of
these studies1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
demonstrated that the
functional capability in the experimental group was greater than in the control
group at three, six, and 12 months after intervention, showing long-term
improvement. Another study1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises
with or without additional hip strengthening exercises in management of
patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil
Med. 2013;49(5):687-98. PMid:23820880 also used the
AKPS and observed that the experimental group showed greater improvement in reported
functional capability compared to the control group. Dolak et al.1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
also used the LEFS, but observed that all
participants, independently of group allocation, showed improvement in the reported
functional capabilities after intervention. This result may be influenced by the
functional exercises performed by all of the participants, as discussed previously.
Ismail et al.1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises
with or without additional hip strengthening exercises in management of
patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil
Med. 2013;49(5):687-98. PMid:23820880 evaluated function using the
AKPS and did not find any differences between groups. The possible explanation for
this result may be similar to that of the absence of differences in pain intensity
and hip muscle strength. Khayambashi et al.1515 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
used the Western Ontario and McMaster Universities Arthritis Index (WOMAC) to assess
function and also observed improvement in the experimental group. Furthermore, the
improvement in the experimental group lasted until six months after
intervention1515 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
, reinforcing the long-term
benefits of hip muscle strengthening on function. Thus, the majority of studies
showed both short and long-term improvement in functional capabilities.
This systematic review had some limitations. As discussed above, the selected studies
applied different methods to evaluate pain intensity, muscle strength, and function
and described different protocols of hip muscle strengthening, which prevented
statistically grouping the results to perform meta-analysis. Differences in
treatment protocols, including program duration, number of sets, and repetitions of
the performed exercises, and the procedure to determine the exercise intensity are
examples of this lack of uniformity. The program lasted four weeks in three
studies1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
,
1717 Razeghi M, Etemadi Y, Sh T, Ghaem H. Could hip and knee muscle
strengthening alter the pain intensity in patellofemoral pain syndrome? Iranian
Red Crescent Medical Journal. 2010;12(2):104-10.
,
1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
, six weeks in two studies1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises
with or without additional hip strengthening exercises in management of
patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil
Med. 2013;49(5):687-98. PMid:23820880
,
1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
, and eight weeks in two other studies1515 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
,
1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
. The number of sets varied between two and
three and the repetitions between 10 and 15. The procedure to determine the exercise
intensity was also heterogeneous among the studies. For example, one study1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises
with or without additional hip strengthening exercises in management of
patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil
Med. 2013;49(5):687-98. PMid:23820880 set the load as 60% of 1-repetition maximum,
two studies1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
,
1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
set it as 70% of 1-repetition maximum, and
one study1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
set it as percentage of body
mass. Apart from this heterogeneity, the studies showed some similarities. The
majority of the programs aimed to strengthen hip abductors1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises
with or without additional hip strengthening exercises in management of
patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil
Med. 2013;49(5):687-98. PMid:23820880
14 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
15 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
16 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
17 Razeghi M, Etemadi Y, Sh T, Ghaem H. Could hip and knee muscle
strengthening alter the pain intensity in patellofemoral pain syndrome? Iranian
Red Crescent Medical Journal. 2010;12(2):104-10.
18 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
-
1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
and hip lateral rotators1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises
with or without additional hip strengthening exercises in management of
patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil
Med. 2013;49(5):687-98. PMid:23820880
14 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
15 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
16 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
17 Razeghi M, Etemadi Y, Sh T, Ghaem H. Could hip and knee muscle
strengthening alter the pain intensity in patellofemoral pain syndrome? Iranian
Red Crescent Medical Journal. 2010;12(2):104-10.
18 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
-
1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
in different positions, such as side
lying, sitting, and standing. There was also a trend in the studies to increase the
exercises' intensity progressively by increasing the load1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises
with or without additional hip strengthening exercises in management of
patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil
Med. 2013;49(5):687-98. PMid:23820880
,
1414 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
,
1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
, changing the elastic resistance1515 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
,
1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
, and/or changing the exercises1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
,
1919 Nakagawa TH, Muniz TB, Baldon RM, Dias Maciel C, Menezes Reiff RB,
Serrão FV. The effect of additional strengthening of hip abductor and lateral
rotator muscles in patellofemoral pain syndrome: a randomized controlled pilot
study. Clin Rehabil. 2008;22(12):1051-60.
http://dx.doi.org/10.1177/0269215508095357 . PMid:19052244
http://dx.doi.org/10.1177/02692155080953...
. Furthermore, the majority of the studies
provided training three times per week1313 Ismail MM, Gamaleldein MH, Hassa KA. Closed kinetic chain exercises
with or without additional hip strengthening exercises in management of
patellofemoral pain syndrome: a randomized controlled trial. Eur J Phys Rehabil
Med. 2013;49(5):687-98. PMid:23820880
14 Fukuda TY, Melo WP, Zaffalon BM, Rossetto FM, Magalhães E, Bryk FF,
et al. Hip posterolateral musculature strengthening in sedentary women with
patellofemoral pain syndrome: a randomized controlled clinical trial with 1-year
follow-up. J Orthop Sports Phys Ther. 2012;42(10):823-30.
http://dx.doi.org/10.2519/jospt.2012.4184 . PMid:22951491
http://dx.doi.org/10.2519/jospt.2012.418...
15 Khayambashi K, Mohammadkhani Z, Ghaznavi K, Lyle MA, Powers CM. The
effects of isolated hip abductor and external rotator muscle strengthening on
pain, health status, and hip strength in females with patellofemoral pain: a
randomized controlled trial. J Orthop Sports Phys Ther. 2012;42(1):22-9.
http://dx.doi.org/10.2519/jospt.2012.3704 . PMid:22027216
http://dx.doi.org/10.2519/jospt.2012.370...
-
1616 Dolak KL, Silkman C, McKeon JM, Hosey RG, Lattermann C, Uhl TL. Hip
strengthening prior to functional exercises reduces pain sooner than quadriceps
strengthening in females with patellofemoral pain syndrome: a randomized
clinical trial. J Orthop Sports Phys Ther. 2011;41(8):560-70.
http://dx.doi.org/10.2519/jospt.2011.3499 . PMid:21654093
http://dx.doi.org/10.2519/jospt.2011.349...
,
1818 Fukuda TY, Rossetto FM, Magalhães E, Bryk FF, Lucareli PRG, Carvalho
NAA. Short-term effects of hip abductors and lateral rotators strengthening in
females with patellofemoral pain syndrome: a randomized controlled clinical
trial. J Orthop Sports Phys Ther. 2010;40(11):736-42.
http://dx.doi.org/10.2519/jospt.2010.3246. PMid:21041965
http://dx.doi.org/10.2519/jospt.2010.324...
. Despite differences among the studies
that prevented statistically grouping the results, the similarities among the
selected studies may have contributed to the positive findings of this review. It
suggests that they should be considered important variables in the analysis of the
effectiveness of hip muscle strengthening.
This review aimed to look at the effectiveness of hip muscle strengthening on pain
intensity, muscle strength, and function in individuals with PFPS. Other studies,
however, have investigated the effects of other types of interventions in patients
with PFPS (e.g. quadriceps strengthening and foot orthoses) and the combination of
interventions or have made comparisons between these interventions2828 Barton CJ, Munteanu SE, Menz HB, Crossley KM. The efficacy of foot
orthoses in the treatment of individuals with patellofemoral pain syndrome: a
systematic review. Sports Med. 2010;40(5):377-95.
http://dx.doi.org/10.2165/11530780-000000000-00000 .
PMid:20433211
http://dx.doi.org/10.2165/11530780-00000...
29 Bolgla LA, Boling MC. An update for the conservative management of
patellofemoral pain syndrome: a systematic review of the literature from 2000 to
2010. Int J Sports Phys Ther. 2011;6(2):112-25. PMid:21713229 .
-
3030 Peters JS, Tyson NL. Proximal exercises are effective in treating
patellofemoral pain syndrome: a systematic review. Int J Sports Phys Ther.
2013;8(5):689-700. PMid:24175148.. The approach chosen by the current review
allowed the selection of studies that specifically investigated the effectiveness of
hip muscle strengthening and a more detailed discussion on the role of hip muscle
strength on reducing pain and increasing function of PFPS patients. The choice of
this approach was motivated by two factors: 1) the theoretical claim that modifying
tissue properties around the hip will improve patellar tracking; and 2) current and
common clinical practice that focuses on hip muscle force and function in
alleviating knee pain. Therefore, the results of this systematic review provide an
updated source of evidence for clinicians and researchers.
This review summarized the literature and evaluated the methodological quality of the RCT already published regarding the effects of hip muscle strengthening in patients with PFPS. The results showed that hip muscle strengthening has an important role in the treatment of PFPS patients, since this intervention is effective in reducing pain intensity and improving function. However, findings regarding the treatments' ability to improve muscle strength were equivocal. The synthesis of data presented here could help researchers to plan future studies. In addition, the results of this review could help in clinical decision making since they support the inclusion of hip muscle strengthening in the treatment of patients with PFPS. The results presented here can also be used by clinicians to explain the treatment's goals to the patients and thus, to increase their adherence to the treatment.
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Publication Dates
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Publication in this collection
29 May 2015 -
Date of issue
May-Jun 2015
History
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Received
17 May 2014 -
Reviewed
03 Nov 2014 -
Accepted
08 Dec 2014