The use of navigation to achieve soft tissue balance in total knee arthroplasty - a randomised clinical study.

BACKGROUND: Achieving soft tissue balance is an operative goal in total knee arthroplasty. This randomised, prospective study compared computer navigation to conventional techniques in achieving soft tissue balance. METHODS: Forty one consecutive knee arthroplasties were randomised to either a non-navigated or navigated group. In the non-navigated group, balancing was carried out using surgeon judgement. In the navigated group, balancing was carried out using navigation software. In both groups, the navigation software was used as a measuring tool. RESULTS: Balancing of the mediolateral extension gap was superior in the navigation group (p=0.001). No significant difference was found between the two groups in balancing the mediolateral flexion gap or in achieving equal flexion and extension gaps. CONCLUSIONS: Computer navigation offered little advantage over experienced surgeon judgement in achieving soft tissue balance in knee replacement. However, the method employed in the navigated group did provide a reproducible and objective assessment of flexion and extension gaps and may therefore benefit surgeons in training. LEVEL OF EVIDENCE: Level I, RCT.

Femoral impaction grafting with cement in revision total hip replacement. Evolution of the technique and results.

We report the results of cancellous femoral impaction grafting with cement in revision hip arthroplasty in all patients from one centre who had undergone surgery more than five years previously. A total of 32 surgeons undertook femoral impaction grafting in 207 patients (226 hips). There were no deaths attributable to the revision surgery; 33 patients with 35 functioning hips died with less than five years' follow-up. One patient was lost to follow-up. Two hips (1%) developed early postoperative infection. Of the 12 stems which underwent a further surgical procedure for aseptic failure, ten were for femoral fracture and two for loosening. Survivorship with any further femoral operation as the endpoint was 90.5% (confidence intervals, 82 to 98) and using femoral reoperation for symptomatic aseptic loosening as the endpoint, the survivorship was 99.1% (confidence intervals, 96 to 100) at 10 to 11 years. As a consequence of the experience in this series, we have modified our technique with an increased use of longer stems with impacted allograft. Long stems are indicated when the host bone around the tip of a short stem is compromised, in patients with major loss of bone stock, or when a femoral fracture occurs.