Effects of Hip Abductor Muscles Exercises on Pain and Function in Patients With Patellofemoral Pain. A Systematic Review and Meta-Analysis

Rogan, S, Haehni, M, Luijckx, E, Dealer, J, Reuteler, S, and Taeymans, J. Effects of hip abductor muscles exercises on pain and function in patients with patellofemoral pain: A systematic review and meta-analysis. J Strength Cond Res XX(X): 000–000, 2018—This systematic review and meta-analysis considered the effects of hip strengthening (i.e., abductor and external rotator muscles) vs. no hip strengthening on pain and of hip strengthening combined with knee strengthening vs. knee strengthening (i.e., quadriceps muscles) alone on pain and functional status in patients with patellofemoral pain (PFP). Eleven, randomized, controlled trial (RCT) studies and 1 non-RCT study were included, totaling 604 participants. Female athletes were included in one study, whereas untrained participants were included in the other studies. On average, the studies showed a low methodological quality. Hip muscle strengthening showed greater pain-reducing effects when compared with no hip strengthening (standardized mean difference [SMD] = −1.91; 95% confidence interval [CI], −2.92 to −0.9; p = 0.0002). When comparing a combined hip and knee muscle strengthening with knee muscle strengthening alone, pain was reduced in the combined hip and knee–strengthening group (SMD −0.99; 95% CI, −1.99 to 0.02; p = 0.05), whereas function showed a SMD of 0.70 (95% CI, 0.25–1.14; p = 0.002) again favoring the combined hip and knee–strengthening group. This meta-analysis showed evidence that the strengthening of the hip abductor muscles can reduce pain and function in patients with PFP. Because studies including highly trained patients with PFP are currently lacking, one should be careful when applying the clinical findings of this meta-analysis when working with athletes. Trial registration: PROSPERO 2014:CRD42014010716.