Hip and Knee Strengthening Is More Effective Than Knee Strengthening Alone for Reducing Pain and Improving Activity in Individuals With Patellofemoral Pain: A Systematic Review With Meta-analysis

Abstract

U t STUDY DESIGN:Systematic review with metaanalysis. U t BACKGROUND:The addition of hip strengthening to knee strengthening for persons with patellofemoral pain has the potential to optimize treatment effects. There is a need to systematically review and pool the current evidence in this area. U t OBJECTIVE:To examine the efficacy of hip strengthening, associated or not with knee strengthening, to increase strength, reduce pain, and improve activity in individuals with patellofemoral pain. U t METHODS:A systematic review of randomized and/or controlled trials was performed. Participants in the reviewed studies were individuals with patellofemoral pain, and the experimental intervention was hip and knee strengthening. Outcome data related to muscle strength, pain, and activity were extracted from the eligible trials and combined in a meta-analysis. U t RESULTS:The review included 14 trials involving 673 participants. Random-effects metaanalyses revealed that hip and knee strengthening decreased pain (mean difference, -3.3; 95% confidence interval [CI]: -5.6, -1.1) and improved activity (standardized mean difference, 1.4; 95% CI: 0.03, 2.8) compared to no training/placebo. In addition, hip and knee strengthening was superior to knee strengthening alone for decreasing pain (mean difference, -1.5; 95% CI: -2.3, -0.8) and improving activity (standardized mean difference, 0.7; 95% CI: 0.2, 1.3). Results were maintained beyond the intervention period. Meta-analyses showed no significant changes in strength for any of the interventions. U t CONCLUSION:Hip and knee strengthening is effective and superior to knee strengthening alone for decreasing pain and improving activity in persons with patellofemoral pain; however, these outcomes were achieved without a concurrent change in strength. U t LEVEL OF EVIDENCE: Therapy, level 1a-.

Patellofemoral pain: One year results of a randomized trial comparing hip exercise, knee exercise, or free activity

“…They found no between‐group differences in pain and function despite superior gains in muscle strength for the exercise group, and superior gains in step rate for the gait retraining group. That clinical improvements are not necessarily tied to improvements in muscle strength is observed in two previous systematic reviews . This may suggest that clinical improvements may be moderated by factors other than muscle strength.…”

“…In interpreting these results, it should be considered that the exercise programs aimed to isolate the muscle groups in question, as opposed to employing a complex or multimodal exercise-based intervention as is most commonly used in PFP. 6,7,9 Further, isolated exercises might be more effective if targeted to specific deficits, as theorized by Selfe et al 44 These factors might affect relative effectiveness of guided exercise compared to the control group. To our knowledge, this is the first study to use patient education attempting to influence kinesiophobia and self-mastery in PFP, despite the potential importance of these factors.…”

“…The lack of between‐group differences in clinical outcomes in this study raises the question whether free training might be as effective as therapist‐guided exercises. In interpreting these results, it should be considered that the exercise programs aimed to isolate the muscle groups in question, as opposed to employing a complex or multimodal exercise‐based intervention as is most commonly used in PFP . Further, isolated exercises might be more effective if targeted to specific deficits, as theorized by Selfe et al These factors might affect relative effectiveness of guided exercise compared to the control group.…”

“…That clinical improvements are not necessarily tied to improvements in muscle strength is observed in two previous systematic reviews. 9,43 This may suggest that clinical improvements may be moderated by factors other than muscle strength.…”

“…6,7 Traditionally, exercise for PFP has been knee-focused with emphasis on strength and coordination in quadriceps muscles, 8 while hip-focused exercise has received increasing attention more recently. 8,9 The most recent Cochrane systematic review concludes with consistent but very low-quality evidence for exercise as a treatment for PFP, and insufficient evidence to recommend a specific type of exercise. 8 Although expert recommendations advocate the combined use of hip and knee exercise, the relative contributions of the components are unclear.…”