Femoral stem displacement during closed reduction of a dislocated bipolar hemiarthroplasty of the hip.

摘要

This article describes a case of femoral stem displacement during closed reduction of a redislocated bipolar hemiarthroplasty of the hip in a 72-year-old woman who had undergone bipolar hemiarthroplasty using a polished, tapered cemented femoral stem. The polished, tapered cemented femoral stem is vulnerable to displacement when exposed to traction forces. Six days after bipolar hemiarthroplasty, the patient experienced her first dislocation, and immediate reduction of the dislocated hip was easily achieved. However, on the ninth postoperative day, redislocation occurred, and this time, reduction was not achieved. Subsequent radiographs revealed an unreduced state with posterosuperior dislocation of the hip and dissociation of the femoral stem at the cement-stem interface with proximal migration. Open reduction was then performed, and it was noted that the bipolar prosthesis had dislocated posterosuperiorly, the neck of the femoral stem was incarcerated between the short external rotators, and the femoral stem had migrated proximally by approximately 8 cm. The femoral stem was repositioned by freeing it from the short external rotators and gently tapping it into the cement mantle. Our surgical solution is questionable, because the stability of the stem is likely to be inadequate. According to the established study, no difference in stuffiness was observed before extraction and after reinsertion, which supports the surgical solution we chose. Pre-reduction analysis should be conducted to determine the cause and status of a dislocation, and open reduction should be performed if closed reduction fails when treating dislocated bipolar hemiarthroplasty patients.