Strengthening of the Hip and Core
Versus Knee Muscles for the Treatment of Patellofemoral Pain: A Multicenter,
Randomized Controlled Trial

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. 

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).

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?

Nicole Cattano
by: Jeffrey Driban

Related Post:

Ferber, R., Bolgla, L., Earl-Boehm, J., Emery, C., & Hamstra-Wright, K. (2014). Strengthening of the Hip and Core Versus Knee Muscles for the Treatment of Patellofemoral Pain: A Multicenter, Randomized Controlled Trial Journal of Athletic Training DOI: 10.4085/1062-6050-49.3.70