Algorithm for Femoral and Periacetabular Osteotomies in Complex Hip Deformities

BACKGROUND: Residual acetabular dysplasia of the hip in most patients can be corrected by periacetabular osteotomy. However, some patients have intraarticular abnormalities causing insufficient coverage, containment or congruency after periacetabular osteotomy, or extraarticular abnormalities that limit either acetabular correction or hip motion. For these patients, we believe an additional proximal femoral osteotomy can improve coverage, containment, congruency and/or motion. PURPOSES: We provide algorithms for (1) identifying patients we believe will benefit from proximal femoral osteotomy, (2) selecting the appropriate osteotomy, and (3) choosing the sequence of these osteotomies. METHODS: Anteroposterior, false-profile and functional radiographs and MR can identify most patients we believe will benefit from periacetabular and femoral osteotomies. Recently described techniques, including relative femoral neck lengthening, femoral neck osteotomy and femoral head osteotomy have expanded indications for a combined procedure. Historically performed first, periacetabular osteotomy is now frequently performed following femoral osteotomy. RESULTS: The rate of intertrochanteric osteotomy performed with periacetabular osteotomy has decreased from approximately 10% in the first 500 surgeries to about 2% currently. Among 151 relative neck lengthenings (23 with PAO), 53 femoral neck osteotomies (4 with PAO) and 14 femoral head osteotomies (11 with PAO), eleven complications occurred including osteonecrosis in two and delayed unions in eight. No complication occurred following a combined procedure. CONCLUSION: Although isolated periacetabular osteotomy can provide sufficient coverage, containment and congruency for most patients with residual hip dysplasia, some may benefit from an additional proximal femoral osteotomy. Knowing the appropriate indications, selection, and sequencing of these osteotomies is critical for enhancing patient outcomes.