Revision knee arthroplasty using a distal femoral replacement prosthesis for periprosthetic fractures in elderly patients.

Abstract

Distal femoral periprosthetic fractures above a total knee replacement in elderly patients are technically challenging to treat. Bone quality is often poor, the fractures comminuted, and post-operative mobilisation is difficult. This study assesses the clinical, radiological and functional outcome of revision knee distal femoral replacement (DFR) in these fractures. We identified 14 patients over 70years of age (70-94) who underwent DFR for periprosthetic fractures above a knee replacement. All the 14 fractures were classified as Su type III. Clinical and radiological records were retrospectively reviewed. The mean of clinical follow-up was 27months (8-46). Functional outcome was assessed using Oxford Knee Score and EQ-5D (UK English Version) score at a mean time of 35months (20-65). The Knee Society patient category score was also evaluated. The median post-operative knee flexion was 100° (range 90°-135°). Nine patients (64%) returned to their pre-fracture level of mobility or better. The median post-operative Oxford Knee Score was 27 (range 4-40). The median EQ-5D was 11 (range 6-12). Cognitive impairment negatively impacted the functional outcome in four patients. One patient died early post-operatively, and two patients had complications. DFR led to satisfactory outcome in our patients with a relatively low complication rate. In our experience, revision knee distal femoral replacement is an appropriate method to treat elderly patients who sustained periprosthetic Su et al. type III distal femoral fractures in association with poor bone stock, caused by osteoporosis and/or comminution.