Foot orthoses have been studied to help anterior knee pain, but the studies are relatively small and the effects are uncertain. Ziyan Chen, MA, and colleagues performed a systematic review and meta-analysis of the effects of foot orthoses on anterior (patellofemoral) knee pain. Two mechanisms of action have been described. One postulated mechanism is by controlling excessive foot pronation, decreasing internal rotation of the tibia and relative lateral displacement of the patella. Alternatively, increased muscle activation of the lower extremity, particularly the vastus medialis and gluteus medius, could decrease excessive lateral motion of the patella.   

In the review, six randomized controlled trials were able to be identified and data extracted for analysis. These trials were relatively small (eight to 46 patients per group). They found that there was no significant effect of foot orthoses on pain intensity, knee symptoms or knee-related quality of life. The analysis of several papers showed that there was a positive effect of foot orthoses on knee function, and two papers found an improvement in the KOOS sports and recreation scale.

These trials were heterogenous, with varying comparison groups. Physical therapy and gait retraining seemed to be superior to foot orthoses in terms of outcomes. There were some data showing some additional benefit for patients with orthoses and therapy compared with therapy alone.

It is not surprising that treatments more directly related to the knee joint may have superior outcomes. The postulated mechanisms of foot orthoses for knee pain are indirect and depend on changing forces closer to the joint, either through tibial rotation or hip/knee muscle activation. There may be some potential benefit for orthoses as part of a multimodal approach to anterior knee pain, but as a sole modality, this paper suggests it may be lacking.