Clinical study of occult fractures around the prosthesis in primary total hip arthroplasty

Objective To determine the prevalence, prevention measures, and risk factors for occult periprosthetic fractures after primary total hip arthroplasty (THA), as well as to determine whether or not they are the root of early THA failure. Methods From January 2014 to December 2018, 755 patients (769 hips) underwent primary total hip arthroplasty were retrospectively analyzed, including 327 males (339 hips) and 428 females (430 hips). X-ray, CT and 3D reconstruction of hip were performed before and after operation. By using CT to diagnose the occult fractures, the patients were then monitored and evaluated. Age, sex, body mass index (BMI), preoperative diagnosis, osteoporosis, kind of prosthesis, and the surgeon's experience should all be considered. Patients with occult fracture were followed up, the fracture healing and prosthesis stability were recorded and analyzed. Results There are 23 of 769 cases (23/769) had occult fracture around the prosthesis, with an incidence of 2.99% (23/769);. The total revision rate was 0.52% (4/769). The revision patients accounted for 17.39% (4/23) of the patients with occult femoral fractures. The remaining patients received conservative care and successfully joined without their prostheses slipping. Osteoporosis, body mass index, and the surgeon's experience were identified as the risk variables for periprosthetic occult fractures by univariate analysis (P < 0.05). Conclusion Periprosthetic occult fracture was a complication that can not be ignored in primary total hip arthroplasty. It is the cause of early failure of prosthesis. Osteoporosis, BMI and the surgeon's experience are all risk factors for periprosthetic occult fractures.