ObjectiveTo investigate the early effectiveness of artificial intelligence (AI) assisted total hip arthroplasty (THA) system (AIHIP) in the treatment of patients with Crowe type Ⅳ developmental dysplasia of the hip (DDH).MethodsThe clinical data of 23 patients with Crowe type Ⅳ DDH who met the selection criteria between May 2019 and December 2020 were retrospectively analyzed. There were 3 males and 20 females, the age ranged from 44 to 74 years, with an average of 52.65 years. The absolute value of the lower limbs discrepancy before operation was (15.17±22.17) mm. The preoperative Harris score was 62.4±7.2. The AIHIP system was used for preoperative planning, and the operations were all performed via conventional posterolateral approach. Thirteen patients with difficulty in reduction during operation underwent subtrochanteric shortening osteotomy (SSOT). The operation time, hospital stay, and adverse events were recorded; Harris score was used to evaluate the function of the affected limb at 1 day before operation and 1 week and 6 months after operation; pelvic anteroposterior X-ray film was taken at 1 day after operation to evaluate the position of the prosthesis. The matching degree of prosthesis was evaluated according to the consistency of intraoperative prosthesis model and preoperative planning.ResultsThe matching degree of acetabular cup model after operation was 16 cases of perfect matching, 4 cases of general matching (1 case of +1, 3 cases of –1), and 3 cases of mismatch (all of them were +2), the coincidence rate was 86.96%. The matching degree of femoral stem model was perfect matching in 22 cases and general matching in 1 case of –1, and the coincidence rate was 100%. One patient had a periprosthesis fracture during operation, and was fixed with a wire cable during operation, and walked with the assistance of walking aid at 6 weeks after operation; the rest of the patients walked with the assistance of walking aid at 1 day after operation. The operation time was 185-315 minutes, with an average of 239.43 minutes; the hospital stay was 8-20 days, with an average of 9.96 days; and the time of disengagement from the walking aid was 2-56 days, with an average of 5.09 days. All patients were followed up 6 months. All incisions healed by first intension, and there was no complication such as infection, dislocation, refracture, and lower extremity deep venous thrombosis; X-ray films at 1 day and 6 months after operation showed that the acetabular and femoral prostheses were firmly fixed and within the safe zone; the absolute value of lower limbs discrepancy at 1 day after operation was (11.96±13.48) mm, which was not significantly decreased compared with that before operation (t=0.582, P=0.564). All osteotomies healed at 6 months after operation. The Harris scores at 1 week and 6 months after operation were 69.5±4.9 and 79.2±5.7 respectively, showing significant differences between pre- and post-operation (P<0.05). At 6 months after operation, the hip function was evaluated according to Harris score, and 13 cases were good, 9 cases were fair, and 1 case was poor.ConclusionAIHIP system-assisted THA (difficult to reposition patients combined with SSOT) for adult Crowe type Ⅳ DDH has high preoperative planning accuracy, easy intraoperative reduction, early postoperative landing, and satisfactory short-term effectiveness.