Successful outcome from foot orthoses and exercises for patellofemoral pain predicted by static foot measurement - A case study

Background: Evidence-based treatments for patellofemoral pain provide short to moderate term improvements, but a substantial proportion of patients still report persistent symptoms. One possible method for improving success rates over the long-term would be to use individual patient characteristics to match the right patient to the appropriate treatment. Midfoot width difference (MWD) of ≥11 mm from a weight bearing to a non-weight bearing foot posture has been identified as predictive of those who will have a successful outcome with foot orthoses to treat patellofemoral pain. This single case study presents a patient with a 10-year history of bilateral patellofemoral pain, and with ≥11 mm MWD, who was successfully treated with foot orthoses and foot muscle retaining. Methods: A 23year old female presented with bilateral peripatellar symptoms (Left > Right) and a worst pain score of 7/10 (numerical pain scale (NPS) 0 = no pain, 10 = worst pain imaginable). The number of pain free step-ups, step-downs and squats were 7,2&6 (left) and 18,3&6 (right) respectively. Left MWD was 12.1 mm and the right was 11.2 mm. Maximal voluntary isometric hip strength measurements were hip abduction (ABD) 71.1N (left) and 70.2N (right), adduction (ADD) 70.6N (left) and 61.1N (right) and external rotation (ER) 67.2N (left) and 64.7N (right). Based on ≥11 mm in MWD, the treatment plan consisted of foot orthoses combined with calf stretching and foot posture retraining. The primary outcome measure was global rating of change scale (GROC) on a seven-point Likert scale. The patient was reviewed 6 times over 7 weeks. At 3 weeks the foot orthoses were removed and the foot exercises progressed. Results: At 16 weeks, the patient reported she was much better on the GROC and her pain was 0/10. Pain free step-up, step-downs and squats were 25, 25 & 25 (left) and 22, 25 & 25 (right) respectively. Hip strength measures were ABD 53.4N (left) and 57.5N (right), ADD 71.2N (left) and 74.1N (right) and ER 74.8N (left) and 78.7N (right). Discussion: This case study demonstrates four key points for discussion. 1. MWD ≥ 11 mm at first assessment being associated with a successful response to foot treatments aimed. 2. Active neuromuscular control of the foot might compliment foot orthosis intervention and improve both short and longer-term outcome. 3. Foot orthoses are likely a temporary adjunct to enable pain control and more effective foot exercising 4. There were substantial differences in hip muscle strength profile with treatment only directed at the foot