Does Acetabulum Remodel Following Varus Derotation Osteotomy for Perthes' Disease?

Area of Science:

• Orthopedic surgery
• Pediatric orthopedics
• Pediatric bone diseases

Background:

• Perthes' disease often involves acetabular dysplasia.
• Acetabular contour is crucial for hip joint function.
• Varus derotation osteotomy of the proximal femur (VDRO) is used for containment in Perthes' disease.

Purpose of the Study:

• To investigate the impact of disease stage, patient age, and femoral head contour on acetabulum contour after VDRO in unilateral Perthes' disease.
• To evaluate the effectiveness of VDRO in improving acetabular dysplasia.

Main Methods:

• Retrospective analysis of 23 children (≥6 years) with unilateral Perthes' disease who underwent primary VDRO.
• Preoperative and follow-up radiographs were used to calculate Acetabular Index (AI) and Center Edge Angle (CEA).
• Statistical comparison of AI and CEA between affected and unaffected hips, and correlation with disease stage, age, and Stulberg grade.

Main Results:

• Preoperative acetabular dysplasia was significant.
• Post-VDRO, AI increased and CEA decreased significantly in affected hips.
• No significant acetabular remodeling was observed, even in younger patients or earlier disease stages (Ib, IIa); remodeling did not correlate with Stulberg grade.

Conclusions:

• Acetabular involvement is present in early Perthes' disease.
• VDRO does not significantly improve acetabular dysplasia in Perthes' disease, regardless of early intervention.
• Residual acetabular changes are common, even with favorable Stulberg grades.