3D printing technology-assisted total hip arthroplasty for acute proximal femoral fracture and Hartofilakidis type II developmental dysplasia of the hip: a case report and literature review.

Developmental dysplasia of the hip (DDH) associated with an acute proximal femoral fracture on the same side is uncommon, and performing a one-stage total hip arthroplasty (THA) with concurrent fracture stabilization in such cases poses significant technical challenges. We present a case involving a 57-year-old female with a long history of right-sided DDH who was involved in a vehicular accident, leading to acute pain in her right hip, shortening of the limb, and restricted movement. Imaging studies indicated Hartofilakidis type II DDH along with a comminuted intertrochanteric fracture of the proximal femur and a pseudoacetabulum. Utilizing thin-slice computed tomography, we created a customized three-dimensional (3D) printed model of the pelvis and proximal femur, which allowed for detailed preoperative planning. This included evaluating the acetabular bone quality, identifying the true center of the acetabulum, selecting the appropriate cup size and orientation, and strategizing the femoral osteotomy and fixation with plates and cables. A one-stage cementless THA was executed through a posterolateral approach, featuring a small hemispherical cup securely placed in the true acetabulum and a size-16 biological femoral stem anchored distally across the fracture site, followed by the application of a lateral plate and titanium cable to stabilize the proximal femoral fracture. The patient began ambulation with the assistance of a walker on postoperative day 1. At 2 months after surgery, the pain score had decreased to 1/10 on the visual analog scale (VAS), and radiographic evaluation demonstrated ongoing fracture healing. By 3 months postoperatively, the patient was pain-free (VAS 0/10), had achieved a Harris Hip Score of 92, and showed restoration of lower-limb length. Imaging confirmed fracture union and stable prosthesis positioning, and the patient had returned to work independently. This case suggests that individualized 3D printing-assisted preoperative planning may improve the feasibility and early safety of one-stage cementless total hip arthroplasty combined with internal fixation for adult DDH with an ipsilateral proximal femoral fracture, and may provide a useful reference for preoperative decision-making in similarly complex cases.