Lateral acetabular growth stimulation following a labral support procedure in Legg-Calve-Perthes disease.

ABSTRACT

BACKGROUND: The main goal of containment treatment in cases of Legg-Calvé-Perthes disease is to prevent hip deformity, which leads to arthritis in adulthood. Recently, the shelf arthroplasty (the labral support procedure) has been proposed as a method of containment. The purpose of the present study was to evaluate growth stimulation of the acetabulum in patients with unilateral Legg-Calvé-Perthes disease by measuring acetabular depth and height following treatment with the labral support procedure. Uninvolved, contralateral hips and hips that were treated with proximal femoral varus osteotomy were used to compare growth. METHODS: Sixty-five consecutive patients with unilateral Legg-Calvé-Perthes disease that had been treated with the labral support procedure (forty-nine) or a proximal femoral varus osteotomy (sixteen) were evaluated on the basis of radiographic and clinical data that had been obtained at the time of surgery as well as at one, three, and five years after surgery. Acetabular dimensions (depth, height, and total depth with shelf) were measured and, to eliminate radiographic magnification error, the data were expressed in ratios between the involved and uninvolved sides. RESULTS: Preoperatively, both surgical groups were comparable. Acetabular depth indexes at the time of surgery were not different between the groups (p = 0.46). At one, three, and five years postoperatively, the mean depth indexes in the labral support group were significantly higher than those in the proximal femoral varus osteotomy group (F = 5.417, p = 0.001), and trend analysis showed a significant quadratic effect over time in the labral support procedure group (F = 13.132, p = 0.001). The acetabular height indexes at the time of surgery were not different between groups and showed 11% to 13% acetabular overgrowth. The acetabular height indexes in both groups remained unchanged at the time of follow-up (F = 2.82, p = 0.1). The total depth index showed decreasing linear trend values over the period studied (F = 35.115, p = 0.001). CONCLUSIONS: Overgrowth of the acetabulum occurs naturally and early in the course of Legg-Calvé-Perthes disease and is more pronounced in terms of height. The labral support procedure induces additional lateral growth of the true acetabulum (excluding the shelf) for three years following surgery, whereas a proximal femoral varus osteotomy does not. Thus, beneficial effects of the labral support procedure are lateral acetabular growth stimulation, prevention of subluxation, and shelf resolution after femoral epiphyseal reossification. LEVEL OF EVIDENCE Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.