Defining the postoperative alpha angle threshold for improved outcomes in posterolateral cam lesions

Area of Science:

• Orthopedic Surgery
• Radiology
• Sports Medicine

Background:

• Femoroacetabular impingement syndrome (FAIS) is a common cause of hip joint degeneration.
• Posterolateral (PL) cam lesions pose surgical challenges due to their location.
• Defining radiographic success criteria for PL cam lesion resection is essential.

Purpose of the Study:

• To correlate postoperative α angle on pelvis AP radiographs with clinical outcomes.
• To identify an optimal postoperative α angle threshold for improved patient-reported outcomes at 2 years.
• To evaluate the efficacy of hip arthroscopy for PL cam lesions.

Main Methods:

• Retrospective analysis of 117 patients (121 hips) undergoing hip arthroscopy for FAIS (2013-2022).
• Measurement of preoperative and postoperative α angles on pelvis AP and Dunn views.
• Assessment of clinical outcomes using HOS-ADL, mHHS, and NAHS; ROC analysis for threshold determination.

Main Results:

• Postoperative α angle < 55° correlated with significantly better functional outcomes (HOS-ADL, mHHS, NAHS).
• ROC analysis indicated α < 55° as a strong predictor of patient-acceptable symptomatic state (PASS) (AUC > 0.72, p < 0.001).
• Multivariate analysis confirmed postoperative α angle < 55° as an independent predictor of improved hip function.

Conclusions:

• A postoperative pelvis AP α angle < 55° is a key threshold for optimal recovery in PL cam lesions.
• Adequate intraoperative resection is vital for enhancing functional outcomes post-hip arthroscopy.
• Further research with larger cohorts and advanced imaging is recommended to refine criteria.