Acetabular rim syndrome revisited

Area of Science:

• Orthopedic Surgery
• Hip Preservation
• Pediatric Orthopedics

Background:

• Acetabular rim syndrome (ARS) with persistent acetabular os is a rare condition.
• Limited literature exists on outcomes for ARS with persistent os in acetabular dysplasia.

Purpose of the Study:

• To characterize adolescent and young adult patients with ARS and persistent os.
• To compare radiological and clinical outcomes of ARS with persistent os to acetabular dysplasia without an os.

Main Methods:

• Retrospective review of a prospective database of patients undergoing periacetabular osteotomy (PAO) for acetabular dysplasia.
• Comparison of 14 hips with persistent os acetabuli (ARS cohort) to 50 control hips without persistent os.
• Assessment of preoperative and postoperative radiographic markers of dysplasia and patient-reported outcome measures (PROMs).

Main Results:

• The ARS cohort presented with more severe preoperative dysplasia (lower lateral centre-edge angle, higher acetabular inclination).
• No significant differences were observed in sex, age at surgery, or BMI between cohorts.
• Postoperative union of the os acetabuli occurred in 46% of hips with follow-up; no significant differences in UCLA or mHHS scores at one year.

Conclusions:

• Acetabular rim syndrome with persistent acetabular os may be associated with more severe acetabular dysplasia.
• Corrective PAO demonstrates a union rate of approximately 50% for the persistent os acetabuli.