Late Diagnosis of Femoral Shaft Perforation During Total Hip Arthroplasty: Case Report.

Introduction: Femoral shaft fractures are recognized complications of total hip arthroplasty (THA); however, femoral cortical perforation is a rare entity and is most often diagnosed intraoperatively or in the early post-operative period. Delayed diagnosis is uncommon and may result in serious complications. This report presents a case of femoral shaft perforation diagnosed 15 days after primary THA and highlights the importance of two-view radiographic evaluation. Case Report: A 68-year-old woman presented to our outpatient clinic for routine suture removal 15 days after primary right THA performed at another institution for osteoarthritis. Postoperatively, she complained of a painful bulging mass on the posteromedial aspect of the thigh. Despite persistent symptoms, she had been evaluated twice by orthopedic surgeons, and anteroposterior (AP) radiographs were repeatedly interpreted as normal. She was able to ambulate with full weight-bearing using a walker. Physical examination revealed a tender posterior thigh mass and pain with passive hip motion. Laboratory studies were unremarkable. Repeat AP radiographs showed no obvious abnormality; however, a lateral radiograph demonstrated catastrophic posteromedial perforation of the femoral shaft with protrusion of the femoral stem just below the lesser trochanter, tenting the skin. Revision surgery was recommended, but the patient chose to return to her primary surgeon. Conclusion: This case demonstrates that femoral cortical perforation after THA may be overlooked despite patient ambulation and normal AP radiographs. Persistent or atypical post-operative thigh pain should prompt thorough evaluation, including lateral radiographs. Routine use of two-view imaging is essential to avoid delayed diagnosis of this rare but potentially serious complication.