Acute fracture of the acetabulum secondary to a convulsive seizure 3 years after total hip arthroplasty.

While aseptic loosening, osteolysis, and infection are the most common causes of failure after total hip arthroplasty (THA), late hip pain can also be the result of acetabular fracture related to trauma and resultant prosthetic failure. However, atraumatic fracture of the acetabulum around a well-fixed acetabular component is unusual. We present a patient with an acetabular fracture resulting from a generalized convulsive attack 3 years after an uncomplicated primary THA. A 33-year-old man presented with acute left hip pain. He had chronic renal insufficiency and had undergone bilateral THA due to avascular necrosis. The night prior to his admission, he suffered a generalized convulsive attack with severe extremity contractions. Afterwards, he had acute left groin pain and had difficulty walking. Physical examination revealed moderate left hip pain as well as a 1-cm shortening of the affected limb. Radiological examination demonstrated an acetabular fracture with medial wall comminution. The acetabular component had migrated medially and rotated horizontally. Revision of the acetabular component with a reinforcement ring and implantation of a cemented acetabular component was realized. Severe muscle spasms during generalized seizures are known to lead to various musculoskeletal injuries (fractures of the proximal humerus, femur, acetabulum, and dislocation of the shoulder). Seizures could also lead to acute periprosthetic fracture of the acetabulum in patients with osteopenia. Therefore careful reaming is required to avoid overmedialization of the acetabular component in those patients.