Bisphosphonate-induced periprosthetic fracture: a cause of painful total hip arthroplasty.

Background. Cases have been reported in the literature of periprosthetic fractures associated with the use of bisphosphonates occurring in the long term following a Total Hip Replacement (THR). We report an interesting case of periprosthetic fracture secondary to bisphosphonate use only a few months after a THR. Case Report. A 72-year-old lady (on bisphosphonates for 10 years) underwent a THR for osteoarthritis. She was pain-free in the first four months postoperatively. Thereafter, she developed spontaneous onset of pain in the lateral aspect of her thigh and groin and found it difficult to weight-bear. X-rays and blood tests were unremarkable. An ultrasound and MRI scan showed no evidence of effusion/collection or periprosthetic fracture. A radionuclide bone scan showed an abnormal appearance of the right femoral shaft. A subsequent CT scan showed an oblique vertical split on the anterior surface of the upper right femoral shaft. This stress fracture was managed nonoperatively with protected weight bearing. She has progressed well with good clinical and radiological signs of fracture healing. Conclusion. This case is an important addition to our knowledge that bisphosphonate-induced periprosthetic stress fractures can be a cause of hip pain only a few months following a THR.