Direct Anterior Approach in Crowe Type III-IV Developmental Dysplasia of the Hip: Surgical Technique and 2 years Follow-up from Southwest China.

objectivesTo summarize our pioneering surgical practice and clinical outcome of Crowe type III-IV developmental dysplasia of the hip (DDH) with a direct anterior approach total hip arthroplasty in a single teaching hospital in Southwest China.

methodsFourteen patients (15 hips) diagnosed with Crowe type III-IV developmental dysplasia of the hip were involved in this single-center retrospective study between 2016 and 2018. A comprehensive surgical procedure, including preoperative planning and algorithms for leg length equalization, intraoperative stepwise soft tissue release, bone defect reconstruction, and an innovative subtrochanteric osteotomy, was described. Furthermore, advancements in intraoperative CT guidance, computer navigation, and nerve monitoring were available for specific demands. The short-term clinical outcome was evaluated at the endpoint of follow-up by three patient-reported functional scales (Harris, WOMAC, and SF-12 scores), and objective data collected at the clinic, including functional recovery (muscle strength of hip flexor and abductor, correction of the pelvic tilt, leg length discrepancy, and limp), radiographic analysis, and complication occurrence.

resultsThe intraoperative variables were carefully recorded. The mean operating times in Crowe type III and IV groups were 115.8 min and 156.2 min, and the median blood loss volumes were 520.5 mL and 810.2 mL, respectively. The general changes in the Harris, SF-12, and WOMAC scores of the two groups were 46.2, 8.7 and 134.3, respectively, at a mean follow-up of 25.4 months. Enhanced recovery of hip abductor muscle strength was identified in 85.7% of the population at the third postoperative month. The equalization of leg length and correction of the pelvic tile were observed at the sixth postoperative month, with a 36-mm decrease in leg length discrepancy. No radiographic evidence of the loosening or migration of the components was observed. A self-innovated subtrochanteric shortening osteotomy was performed in five patients, and they healed after 6 months. Specific complications included two cases of distal femoral cracks and one case of a periprosthetic fracture needing internal fixation. Two patients received a late iliotibial band release at the 3rd month postoperatively due to progressive genu valgum. No records of infection, dislocation, nerve palsy, bone non-union, or revision surgery were identified. DISCUSSION: The direct anterior approach total hip arthroplasty showed potential advantages, including optimum component positioning, improved hip stability, steerable complication rate, and enhanced functional recovery with Crowe type III-IV DDH. The short-term outcome is comparable to that of the traditional posterolateral approach.