PROXIMAL IMPACTION ALLOGRAFTING FOR FEMORAL REVISION USING THE OXFORD TRIMODULAR STEM

Abstract

Bone stock loss secondary to debris and mechanic alin-stability presents a challenge in revision hip arthroplasty. The aim of our study is to evaluate the clinical outcome of revision hip arthroplasty using the Oxford hip prosthesis combined with impaction allografting.

Between 1999 and 2002, we revised 72 hips in 69 patients using this technique (mean age 65years). Indications were aseptic loosening (56), infection (8), peri-prosthetic fracture (7) and a broken stem (1). The mean time to revision was 8.5 years (1–21years). Patients were assessed clinically and with the Oxford Hip Score (OHS) pre- and post-operatively. Fifty-seven patients also had acetabular revision. Four patients required femoral osteotomy to remove the old prosthesis. We used a mean of 1.8 (1–4) femoral heads per operation.

Patients were mobilised partially weight bearing (8weeks) followed by a gradual return to full loading. Complications included peri-operative femoral fracture (6), infection (6), dislocation (10), DVT (1)and PE (2). The average blood transfusion was 1.8 units (0–9). The OHS improved from 45 (26–58) pre-operatively to 24.3 post-operatively (12–43). No hip has been re-revised for aseptic loosening at a mean follow-up of 32.7months (16–51).

The Oxford hip is a trimodular prosthesis with a polished tapered metaphyseal section that is free to slide and rotate on the stem. The stem is first inserted uncemented into the diaphysis. Bone graft is impacted proximally, with mesh if necessary, and then the proximal wedge is cemented in. The wedge allows for some subsidence in the cement and creates optimal radial force transmission, which is essential for bone-remodelling stimulation and preventing proximal stress shielding. Although this is a short-term experience, we believe that the use of the tri-modular Oxford stem combined with minimal proximal impaction allografting is a reliable method of dealing with difficult revision femoral surgery. The results were comparable with a primary arthroplasty in terms of pain relief and functional results.