Efficacy of hip strengthening on balance and function outcomes in chronic ankle instability: a systematic review and meta-analysis

Chronic ankle instability (CAI) involves not only local mechanical damage to the ankle joint but also accompanying muscle control deficits in the proximal limb. Although hip muscles play a crucial role in postural control within the lower limb, the overall effectiveness of hip strengthening exercises in the rehabilitation of CAI patients remains unclear. Major databases including PubMed, Embase, Cochrane Library, and Sport Discus were searched to identify randomized controlled trials (RCTs) comparing hip strengthening exercises with control. Primary outcome measures included dynamic balance assessed by the Star Excursion Balance Test (SEBT/YBT), static balance assessed by center of pressure (COP) parameters, and foot and ankle ability measure (FAAM) scores. Effect sizes were pooled using a random-effects model. Nine RCTs involving 306 participants were included. Meta-analysis results showed that hip strengthening exercises significantly improved dynamic balance in patients with CAI, specifically demonstrated by increased anterior (SMD = 0.72, 95% CI: 0.25–1.18, P = 0.003), posterolateral (SMD = 1.35, P < 0.0001), and posteromedial (SMD = 1.66, P < 0.0001) reach distances in the SEBT/YBT test. In terms of static balance, the intervention group showed a significant reduction in COP ellipse area (MD = -11.62 mm², 95% CI: -20.77 to -2.47, P = 0.013) and a significant shortening of the movement path length (MD = -56.33 mm, P < 0.05), indicating improved postural control. Regarding foot and ankle function, the intervention group had higher FAAM-ADL scores (MD = 4.32, 95%CI: 1.06–7.58, P = 0.010) and higher FAAM-Sport scores (MD = 5.26, P = 0.007), indicating improved foot and ankle function. Hip strengthening exercises can effectively improve dynamic and static balance control abilities in patients with chronic ankle instability, especially posterior dynamic stability, and improve ankle function. It is recommended to include targeted hip strengthening exercises in the routine rehabilitation program for CAI to optimize treatment outcomes and prevent re-injury.