Lateral shelf acetabuloplasty in the treatment of Legg–Calvé–Perthes disease: Improving mid-term outcome in severely deformed hips

Purpose To evaluate the efficacy and safety of lateral shelf acetabuloplasty in Legg–Calvé–Perthes (LCP) hips classically associated with poor prognosis. Methods A retrospective study was conducted on 30 consecutive pediatric patients (average age 8.6 years) presenting with a severe and progressive form of LCP disease, with (16 hips) or without (14 hips) femoral varus osteotomy (FVO), and treated by lateral shelf acetabuloplasty. Shelf was done on hips presenting an aspherical incongruency with flattening, subluxation, and lack of femoral head coverage, as demonstrated on pre-operative radiographs and arthrography. All patients were reexamined at an average follow-up of 9.5 years (range 5.2–12 years). Clinical, radiological, and computed tomography scan evaluations were undertaken. Stulberg and Mose classifications were applied as radiological indicators of prognosis. Statistical analysis was performed using Student's t test and the Pearson correlation test with variance analysis for repetitive measures. Results At the last follow-up, all patients were pain free and had normal or almost normal hip motion. Twenty-seven patients are now able to walk normally or with a slight limp. Eighteen hips are classified as Stulberg 1 or 2, and 18 hips are classified as Mose 1 or 2. The average neck-shaft angle is 127°. A statistically significant improvement in the majority of radiographic parameters was found. There was no statistically significant worsening of leg length discrepancy following the procedure. The scanographic study found neither offset nor migration of the shelf in any of the hips. The average coronal and anteroposterior length of the shelf was 9.9 and 25 mm, respectively. A borderline positive correlation was found between Wiberg angle improvement and young age at the time of surgery. There was no statistically significant difference between hips that underwent shelf procedures alone and those in which it was combined with FVO. Conclusion Lateral shelf acetabuloplasty improves the outcome of hips with severe LCP. The combined procedure insures a better and lasting coverage and remodeling of the femoral head, while preserving acetabular roof growth.