Reduced Hip Adduction Is Associated With Improved Function After Movement-Pattern Training in Young People With Chronic Hip Joint Pain

Study Design Ancillary analysis, time-controlled randomized clinical trial. Background Movement-pattern training (MPT) has been shown to improve function among patients with chronic hip joint pain (CHJP). Objective To determine the association among treatment outcomes and mechanical factors associated with CHJP. Methods Twenty-eight patients with CHJP, 18 to 40 years of age, participated in MPT, either immediately after assessment or after a wait-list period. Movement-pattern training included task-specific training to reduce hip adduction motion during functional tasks and hip muscle strengthening. Hip-specific function was assessed using the Modified Harris Hip Score (MHHS) and Hip disability and Osteoarthritis Outcome Score (HOOS). Three-dimensional kinematic data were used to quantify hip adduction motion, dynamometry to quantify abductor strength, and magnetic resonance imaging to measure femoral head sphericity using the alpha angle. Paired t tests assessed change from pretreatment to posttreatment. Spearman correlations assessed associations. Results There was significant improvement in MHHS and HOOS scores (P≤.02), adduction motion (P = .045), and abductor strength (P = .01) from pretreatment to posttreatment. Reduction in hip adduction motion (r = -0.67, P<.01) and lower body mass index (r = -0.38, P = .049) correlated with MHHS improvement. Alpha angle and abductor strength change were not correlated with change in MHHS or HOOS scores. Conclusion After MPT, patients reported improvements in pain and function that were associated with their ability to reduce hip adduction motion during functional tasks. Level of Evidence Therapy, level 2b. J Orthop Sports Phys Ther 2018;48(4):316-324. doi:10.2519/jospt.2018.7810.