Excellent 12-month outcomes after hip arthroscopy for femoroacetabular impingement: role of spinopelvic alignment and hip morphology—a multicenter study

Abstract Background Hip arthroscopy for femoroacetabular impingement yields favorable average results, yet many patients do not achieve truly excellent function. The influence of pre-operative radiographic and spinopelvic parameters on excellent short-term outcomes remains uncertain. We aimed to identify pre-operative radiographic and spinopelvic factors associated with achieving an excellent patient-reported outcome at 12 months after arthroscopic treatment of femoroacetabular impingement. Methods A retrospective multicenter study of prospectively collected data was performed across six French centers. Consecutive patients treated arthroscopically for symptomatic femoroacetabular impingement between September 2020 and October 2021 were included if the 12-month Non-Arthritic Hip Score was available. Standard hip radiographs were used to measure degenerative grade, lateral centre-edge angle, and the Dunn alpha angle. Spinopelvic parameters were assessed on low-dose biplanar imaging in standing and sitting, including intrinsic pelvic mobility (standing minus sitting sacral slope). The primary endpoint was an excellent outcome defined as a 12-month Non-Arthritic Hip Score of at least 92. Missing spinopelvic data were handled by multiple imputation, and univariate then multivariable logistic regression was used, adjusted for age, sex, and body mass index. Results Of 200 eligible patients, 178 (89.0%) had 12-month outcome data; 82 (46.1%) achieved a Non-Arthritic Hip Score of at least 92. In the adjusted model, standing pelvic tilt of 10 degrees or less (odds ratio 2.82; 95% confidence interval 1.35–5.90), degenerative grade 0 (odds ratio 5.15; 95% confidence interval 2.19–12.09), lateral centre-edge angle greater than 25 degrees (odds ratio 3.08; 95% confidence interval 1.41–6.74), and male sex (odds ratio 3.18; 95% confidence interval 1.38–7.32) independently predicted an excellent outcome. Intrinsic pelvic mobility, standing lumbar lordosis, Dunn alpha angle, age, and body mass index were not independently associated with excellent outcome. Conclusions Only about half of patients undergoing hip arthroscopy for femoroacetabular impingement achieved an excellent 12-month outcome. Tonnis grade 0, lateral centre-edge angle greater than 25 degrees, standing pelvic tilt of 10 degrees or less, and male sex independently predicted excellent results, whereas pelvic mobility, standing lumbar lordosis, age, and body mass index did not.