Individuals With Patellofemoral Pain Have Less Hip Flexibility Than Controls Regardless of Treatment Outcome.

Abstract

To examine differences in hip flexibility before and after a 6-week muscle strengthening program between those with patellofemoral pain (PFP) and healthy controls. Single-blind, multicentered, randomized controlled trial. Four clinical research laboratories. Physically active individuals (199 PFP and 38 controls). Patellofemoral pain and control subjects were randomized into either a hip-focused or a knee-focused muscle strengthening treatment program. Pain-visual analog scale (centimeter), function-Anterior Knee Pain Scale (points), flexibility-passive goniometry (degrees): hip adduction (HADD), hip external rotation (HER), hip internal rotation (HIR), total hip rotation (HROT), hip extension (HEXT) were measured before and after the muscle strengthening treatment program. Subjects with patellofemoral pain who successfully completed the treatment program (n = 153) had 65%, 25%, 18%, and 12% less HADD, HER, HROT, and HIR ranges of motion (ROMs), respectively, than controls (P < 0.05). Patellofemoral pain subjects who did not successfully complete the program (n = 41) had 134%, 31%, 22%, and 13% less HADD, HER, HROT, and HIR ROMs, respectively, than controls (P < 0.05). All subjects increased their HIR, HROT, and HEXT ROMs pretest to posttest (P < 0.05), but by less than 2 degree. Individuals with PFP had less hip flexibility than controls regardless of treatment outcome or time. After the 6-week muscle strengthening program, and regardless of treatment success, PFP and control subjects experienced a small but clinically insignificant improvement in hip flexibility. Hip ROM should be considered as a targeted area of focus in a rehabilitation program for physically active individuals with PFP.