ObjectiveTo explore the feasibility and effectiveness of total hip arthroplasty (THA) with acetabulum structural bone grafting using autogenous femoral head through direct anterior approach (DAA) in lateral decubitus position in the treatment of Crowe type Ⅲ and Ⅳ developmental dysplasia of the hip (DDH). Methods Between June 2016 and July 2020, 12 patients with Crowe type Ⅲ and Ⅳ DDH were treated with THA with acetabulum structural bone grafting using autogenous femoral head through DAA in lateral decubitus position. There were 2 males and 10 females with an average age of 60.2 years (range, 50-79 years). Crowe classification was type Ⅲ in 10 hips and type Ⅳ in 2 hips. The preoperative Harris score of hip joint was 48.8±7.5, the difference in length of both lower extremities was (3.0±0.7) cm, and the visual analogue scale (VAS) score during activity was 7.2±0.9. The surgical incision length, operation time, intraoperative blood loss, and complications were recorded; the position and press-fitting of acetabulum and femoral prosthesis were observed after operation, and the difference in length of both lower extremities was measured; the horizontal coverage of acetabular cup and bone graft were measured, the healing with the host bone and the loosening of the prosthesis were evaluated; Harris score was used to evaluate hip joint function, and VAS score was used to evaluate patients’ pain during activity. Results The average surgical incision length was 9.3 cm, the average operation time was 117 minutes, and the average intraoperative blood loss was 283 mL. Two patients (16.7%) received blood transfusion during operation. There was no acetabular and femoral fractures during operation. All incisions healed by first intention, without dislocation, periprosthetic infection, sciatic nerve injury, deep venous thrombosis, and other complications. One patient had lateral femoral cutaneous nerve injury after operation. X-ray films at discharge showed a total acetabular cup level coverage of 93%-100%, with an average of 97.8%, and a bone graft level coverage of 25%-45%, with an average of 31.1%. All the 12 patients were followed up 22-71 months, with an average of 42.2 months. At last follow-up, the Harris score of hip joint was 89.7±3.9, the difference in length of both lower extremities was (0.9±0.4) cm, and the VAS score during activity was 1.1±0.6, which were significantly different from those before operation (P<0.05). During follow-up, there was no patient who needed hip revision surgery because of prosthesis loosening. At last follow-up, there was no translucent line between the graft and the host bone, the graft was fused, the position was good, and there was no obvious movement. One patient had one screw fracture and bone resorption at the outer edge of the graft, but the bone graft did not displace and healed well. ConclusionTHA with acetabulum structural bone grafting using autogenous femoral head through DAA in lateral decubitus position in the treatment of Crowe type Ⅲ and Ⅳ DDH is safe and reliable, and has satisfactory short-term effectiveness.