Strengthening of the Hip and Core Versus Knee Muscles for the Treatment of Patellofemoral Pain: A Multicenter, Randomized Controlled Trial
Ferber R, Bolgla L, Earl-Boehm JE, Emery C, & Hamstra-Wright K. Journal of Athletic Training. 2014. 40(3): Epub ahead of print.
Take Home Message: A randomized clinical trial revealed that 6 week rehabilitation protocols focusing on either hip/core or knee strengthening both improve symptoms associated with patellofemoral pain.
Patellofemoral pain (PFP) is a chronic and debilitating condition that affects many physically active individuals. Hip and core strengthening in combination with knee strengthening has proven to be successful in managing PFP. However, no one has compared a PFP rehabilitation program focused on hip-core exercises with a program focused on knee exercises. The authors of this randomized clinical trial tested if either rehabilitation program was better for managing PFP. The authors screened over 700 people and identified 199 recreationally active individuals who had knee pain for at least 4 weeks and several other criteria for PFP. The authors assessed the 199 PFP patients for self-reported worst pain in previous week (visual analogue scale), self-reported physical function (anterior knee pain scale), muscular strength (hip abduction, internal and external rotation, knee extension), and core muscular endurance (front-plank and side-bridge exercises, and horizontal-extension test). Participants completed self-reported outcomes at pre-rehabilitation, weekly, and post-rehabilitation while muscular strength and endurance measures were only assessed pre- and post-rehabilitation. The participants were randomized to either a traditional knee rehabilitation program or a hip and core focused rehabilitation program (see link above for rehab protocol). At the final follow-up, 146 participants completed the study. Both rehabilitation protocols had approximately 80% success rates based on improved symptoms; however individuals in the hip/core protocol showed an improvement 1 week earlier than individuals in the knee protocol. Individuals in the hip/core protocol also had greater increases in hip abduction and extensor strength than individuals in the knee protocol. Individuals in both rehabilitation groups showed increases in posterior core endurance (horizontal-extension test).
This study provides support that either rehabilitation program provides relatively successful PFP relief. The authors noted that exercises included in either group do not truly isolate strengthening to the involved joint since the muscles typically cross both joints. The findings of this study show that a mix of the exercises can be done, however, that the hip/core protocol improved hip abduction and extensor strength better than the knee protocol. Given that the patients in the hip/core group improved 1 week earlier, it may be advantageous as clinicians to focus on hip/core strengthening early in the rehabilitation process for more immediate relief. This finding supports the consensus of earlier posts that we have had on SMR indicating that hip strengthening improves PFP and that it improves it more quickly than quadriceps strengthening. While either protocol was deemed unsuccessful in approximately 20% of the participants in either group, it would be interesting to see or understand why it was unsuccessful. The information gathered on the participants who had unsuccessful outcomes may help us identify key variables or predict the likelihood of success in either protocol. Ultimately as clinicians, rehabilitation is key for reducing limitations and symptoms caused by PFP, but the debate seems to continue on which muscles to target. It is important to identify each patient’s deficits and to tailor a program to meet those needs. This may entail hip-, core-, and knee-focused exercises. This study suggests that on average a patient with PFP may benefit from any of these types of exercises and that incorporating hip and core exercises early may be advantageous. Hence, this can offer us a road map to how we treat the patient sitting across from us.
Questions for Discussion: Do you find yourself focusing on hip or knee musculature when dealing with PFP? Are there any other factors that you focus on during your rehabilitation programs?
Written by: Nicole Cattano
Reviewed by: Jeffrey Driban