Changes in Hip, Knee, and Ankle Coronal Alignments After Total Hip Arthroplasty With Transverse Femoral Shortening Osteotomy for Unilateral Crowe Type IV Developmental Dysplasia of the Hip.

BACKGROUND: To investigate changes in lower extremity coronal alignment in patients with unilateral Crowe type IV developmental dysplasia of the hip who underwent total hip arthroplasty with transverse femoral shortening osteotomy.

METHODS: We reviewed the preoperative and 1-year postoperative full-length lower extremity radiographs of 25 patients. Femoral offset (FO), mechanical hip-knee-ankle angle, anatomical axis, mechanical axis deviation (MAD), mechanical lateral proximal femoral angle, anatomical medial proximal femoral angle, mechanical lateral distal femoral angle, anatomical lateral distal femoral angle, knee joint line congruency angle, mechanical medial proximal tibial angle, mechanical lateral distal tibial angle, ankle joint line orientation angle, tibial plafond talus angle, extremity length, and pelvic obliquity were measured on both the operative and nonoperative sides.

RESULTS: Postoperatively, there were significant changes in FO (P = .001), hip-knee-ankle angle (P = .004), MAD (P = .016), mechanical lateral proximal femoral angle (P = .001), anatomical medial proximal femoral angle (P = .012), mechanical lateral distal femoral angle (P = .043), and ankle joint line orientation angle (P = .012) on the operative side. Only MAD (P = .035) changed significantly on the nonoperative side.

CONCLUSION: Modification of FO and reconstruction of hip joint anatomy led to neutralization of knee and ankle valgus alignment. Effects on the nonoperative side were minimal.