Six-month rehabilitation following surgical hip dislocation for femoroacetabular impingement restores the preoperative strength of most hip muscles, except for external rotators

The aim of this study was to evaluate the bilateral changes in hip muscle strength after a 6-month rehabilitation period for patients undergoing surgical hip dislocation (SHD) to treat femoroacetabular impingement syndrome (FAIS). We conducted a retrospective analysis on a cohort of 22 patients (mean ± SD age: 26 ± 7, 68% male) who underwent SHD for FAIS between March 2020 and January 2023 at La Tour Hospital. Bilateral isometric strength of eight hip muscle groups (abductors, adductors, hamstrings, quadriceps, extensors, flexors, internal, and external rotators) was assessed using a handheld dynamometer before surgery, and at 3 and 6 months postoperatively. After 6 months of rehabilitation, only the external rotators were weaker compared to preoperative levels (-13% ± 23%, <i>P</i> = .021). Strength levels were similar to preoperative levelsfor adductors (-2% ± 21%, <i>P</i> = .309), internal rotators (0% ± 25%, <i>P</i> = .444), quadriceps (0%± 23%, <i>P</i> = .501), hamstrings (7%± 20%, <i>P</i> = .232), extensors (7%± 19%, <i>P</i> = .336), flexors (8%± 34%, <i>P</i> = .781), and abductors (8% ± 25%, <i>P</i> = .266). At 6 months, 59% (abductors) to 82% (adductors) of patients did not achieve a clinically relevant strength improvement (>15%) compared to their preoperative status for aforementioned muscles. Additionally, 50% of the cohort experienced a clinically relevant loss of strength in the external rotators at 6 months post-surgery. To conclude, after SHD, most FAIS patients regained their preoperative strength for all muscle groups except the external rotators with a 6-month rehabilitation program. However, the effectiveness of the rehabilitation protocol varies on an individual level.