Atypical femoral fracture post total hip replacement in a patient with hip osteoarthritis and an ipsilateral cortical thickening.

INTRODUCTION: Atypical femoral fractures (AFF) can be present in patients with hip osteoarthritis (OA). This case highlights the opportunity to review the management of stress reactions, stress fractures and atypical femoral fractures, which depend on the activity of the fracture.

CASE PRESENTATION: A 66-year-old female with a history of long-term bisphosphonate use underwent a total hip replacement for symptomatic osteoarthritis with a clinical presentation of right groin pain and radiographic signs of joint space narrowing and osteophyte formation. Radiographs before hip arthroplasty showed lateral cortical thickening in the ipsilateral femur in the subtrochanteric region. The patient developed a complete periprosthesic atypical femoral fracture a month after surgery at the level of the previously identified femoral cortical thickening.

DISCUSSION: Given the high amount of elderly, osteoporotic patients presenting with groin/thigh pain undergoing hip replacement, surgeons should question them about the use of bisphosphonates in the past and look for the presence of AFF. These should receive bilateral imaging studies and a metabolic bone workup in order to define the status of the fracture and determine the appropriate management before considering any other surgical intervention.