A Case Report of Insufficiency Fracture of the Fossa Acetabuli in a Patient with Rheumatoid Arthritis

Aside from vertebral compression fractures, the most common site of insufficiency fractures is the pelvis and lower extremities. In the pelvis, the fractures usually occur in the ilium, the pu-bis and the ischium, but rarely in the fossa acetabuli. We report a severe insufficiency fracture of the fossa acetabuli in a 78-year-old woman with rheumatoid arthritis (RA) . She had associated insufficiency fractures of the rib, the thoracic spine and the sacrum. In our case, senile osteoporosis was present before the onset of the fracture was recognized on radiographs, and RA and corti-costeroid therapy might have further aggravated the porosis, resulting in the destruction of the fossa acetabuli. Regarding treatment for the fracture, a cemented total hip replacement without bone graft was attempted for several reasons such as the patient' s activities, postoperative reha-bilitaion and the bone mass of the acetabulum. The postoperative course was satisfactory during study period. However, further follow-up is needed to monitor carefully how the patient will be in the future. (J Nippon Med Sch 2000; 67： 267 270)