Stress fracture of femoral stem of hip resurfacing a cause of sudden onset hip pain- A case report and review of literature.

Resurfacing arthroplasty of the hip has had a difficult last decade. Fracture of the femoral neck has been a known complication of resurfaced hip replacement; however, fracture of the metal peg within the femoral component has only been reported twice. We encountered and treated a patient with a unique type of metal failure. A 45 year old lady had advanced arthritis of her left hip secondary to rheumatoid disease. In 2006, an ASR resurfacing arthroplasty was performed and excellent function of the hip was achieved. After 9 years, she experienced an acute pain in the hip without trauma. Serial radiographs before & after the onset of symptoms did not reveal any significant abnormality. MRI scan did not suggest any adverse features too. No evidence emerged in favour of adverse reactions to metal debris (ARMD). Decision to revise the hip was taken with suspicion of an occult fracture. At surgery, the stem of the femoral component was found fractured at its junction with the dome, the dome being still well fixed with the femoral neck. The acetabular component was well fixed. Till date she is very satisfied with the revised hip. Fracture of the femoral peg at its junction to the dome is a complication of hip resurfacing that has not been previously reported in the literature. On the retrieved specimen, instead of 'beach lines' indicative of failure of the material over a prolonged period, we observed only a notched area of bending on the medial side of the implant. This is indicative of an acute event. We wish to make surgeons aware of this particular complication when investigating a similar Case presentation. There is unlikely any standard investigation that diagnoses the fractured implant accurately.

Systemic effects of cobalt toxicity after revision hip replacement can manifest in intermediate to long term follow-up.

INTRODUCTION: Metal toxicity from metal-on-metal hip replacements is now well documented and several large series have reported local reactions. Although less common, there are reports of similar reactions from failed ceramic liners. Systemic effects documented in literature have been grouped into cardiac, neuro-ocular and thyroid signs. METHODS AND RESULTS: We report a case of a patient who had revision for fractured ceramic liner to metal on polyethylene. Third body effect of the ceramic particles led to wear through of the poly liner and the head directly articulating with metal shell. He developed cardiac and neurological features of cobalt toxicity in addition to extensive soft tissue destruction. Revision of the bearing surfaces and synovectomy led to clinical improvement and fall in metal ion levels. CONCLUSIONS: We recommend 2-stage revision in such situations and close monitoring of all these patients.

Primary and revision THA using a stemless metaphyseal-loading implant above distorted proximal femoral anatomy.

Total hip arthroplasty is well established as a successful treatment for end stage arthritis, with a wide variety of components currently available. Using traditional stemmed implants in patients with a distorted proximal femur can be technically challenging with an increased risk of complications. We present seven patients with distorted proximal femoral anatomy or failed hip arthroplasty in whom a short, metaphyseal loading implant was utilised. At minimum two-year follow-up there have been no complications with all stems stable and well fixed radiologically. Average improvement in Oxford Hip Score is 32. We suggest that a short, metaphyseal loading prosthesis can be considered in cases where a conventional stemmed implant may not be suitable due to challenging proximal femoral anatomy.

Conversion of a long distally fixed uncemented revision femoral stem to a proximally fixed implant following fatigue fracture.

There has been increasing focus on bone conservation through proximal fixation in primary hip arthroplasty. However, the debate regarding fixation in revision arthroplasty and which factors influence implant choice remains less clear-cut. We report a case involving fatigue fracture of a long, distally well-fixed, uncemented revision stem. This was revised to a proximally fixed implant. This case highlights a number of issues when considering the choice of implant in hip revision surgery and raises the issue of bone conservation in revision surgery. We would suggest that in both primary and revision hip arthroplasty meticulous pre-operative consideration of the choice of implant should be undertaken, especially in the younger patient with higher expectations and functional demands.