Abstract
We have investigated whether improvements in design have altered outcome for patients undergoing endoprosthetic replacement of the distal femur following tumour resection.
Survival of the implant and ‘servicing’ procedures has been documented using a prospective database and review of the implant design records and case records.
A total of 335 patients underwent a distal femoral replacement with 162 having a fixed hinge design and 173 a rotating hinge. The median age of the patients was 24 years (range 13–82yrs). With a minimum follow up of 5 years and a maximum of 30 years, 192 patients remain alive with a median follow up of 11 years. The risk of revision for any reason was 17% at 5 years, 33% at 10 years and 58% at 20 years. Aseptic loosening was the most common reason for revision in the fixed hinge knees whilst infection and stem fracture were the most common reason in the rotating hinges. The risk of revision for aseptic loosening in the fixed hinges was 35% at ten years but appears to have been abolished by the use of a the rotating hinge knee with a hydroxyapatite collar. The overall risk of revision for any reason was halved by use of the rotating hinge.
Improvements in design of distal femoral replacements have significantly decreased the risk of revision surgery but infection remains a serious problem for all patients. We believe that a cemented, rotating hinge prosthesis with a hydroxyapatite collar offers the best chance of long term prosthesis survival.
Correspondence should be addressed to Ms Larissa Welti, Scientific Secretary, EFORT Central Office, Technoparkstrasse 1, CH-8005 Zürich, Switzerland
