Stress fracture of the femoral stem of a hip endoprosthesis in a patient with high BMI

Complications can occur after total hip replacement surgery, due to various surgical or patient related factors, such as elevated BMI, level of activity and compliance. Fracture of an implant is a rather rare complication worldwide, however it can occur and create necessity for revision arthroplasty. Case report:Patient, 63 year old male, obese (1.85m, 170kg BMI 49.67) with several comorbidities had undergone right side total hip arthroplasty (THA) due to osteoarthritis of the right hip joint 3 years prior. A total cemented implant was used with a size 12 lateralized femoral stem, size 32 M femoral head. Neck-shaft angle of femoral component was 128°. The patient was discharged without early postoperative complications. After primary arthroplasty the patient had gained ~ 10kg of body weight, however walking and daily activity was satisfactory. Three years after THA the patient felt sudden pain in his right hip joint, without any trauma and could not stand on his right leg. X-ray findings displayed a fracture of the femoral component at the base of neck level. A revision hip arthroplasty was scheduled and performed. The primary femoral stem, head and bone cement from the femoral canal was removed, and a size 10 cemented standart stem (neck-shaft angle 135°) and a 32mm M head was implanted. The postoperative period was without complications, and the patient began early range of motion exercises and was discharged with overall improvement. Keywords: Hip arthroplasty, BMI, implant fracture. Increased patient body weight, as well as femoral neck-shaft angle <135° of an implant can cause implant fractures, which require revision and therefore make rehabilitation more difficult.