A modified angled plate for fixation of proximal femoral varus osteotomy in neuromuscular hip dislocation: Mechanical and clinical study.

Introduction: Proximal femoral osteotomy is an important step in the management of paralytic hip dislocation. Fixation by the angled plate is demanding and carries the risk of many complications. In this study, we made certain modifications for the angled plate. Does this plate provide a stable fixation for proximal femoral varus osteotomy? The main objective of this study was to assess the results of the modified plate in fixation of proximal femoral varus osteotomy in patients with neuromuscular hip dislocation.

Hypothesis: This new system would offer significant advantages over the existing systems in terms of easy application and stable fixation.

Material And Methods: Twenty patients with paralytic hip dislocation were included in this study. The ages ranged from 5 to 15 years with a mean of 8.88±2.92 years. There were 12 boys and 8 girls. Seventeen patients had cerebral palsy and 3 had meningocele disease. Preoperative radiographs were done, and the migration percentage (MP), acetabular index (AI), and neck-shaft angle (NSA) were measured. All patients were treated with open reduction, pelvic osteotomy, and proximal femoral varus osteotomy. The femoral osteotomy was fixed by the modified angled plate in all cases.

Results: The osteotomy sites united in all patients and the mean time of union was 2.9±0.65 months. The acetabular index, migration percentage, and neck-shaft angle were reduced postoperatively. This reduction was statistically significant. The hips remained stable throughout the period of follow-up in all patients. No cases were complicated by non-union or implant failure.

Conclusion: The modified angled plate (canulated interlocking blade Plate 90°) is a good method for the fixation of proximal femoral varus osteotomy in the management of neuromuscular hip dislocation. It provides a stable fixation.

Level Of Evidence: IV; case series.