Abstract
We report the clinical and radiographic outcome of a consecutive series of 219 hydroxyapatite-coated total knee replacements with a follow-up of 5 to 8 years.
Patients who fulfilled the entry criteria were included in a prospective study from early 1997 to late 1999. Regular clinical & functional assessment was subsequently performed using the Knee Society Score, WOMAC & SF-12 self-assessment questionnaires. Analysis of fluoroscopically controlled radiographs was performed using the American Knee Society Score.
All living patients (186 knees) were followed-up. Exhaustive efforts were made to ensure that no patient was lost to follow-up. 28 patients (30 knees) were deceased. There have been 3 revisions.
The mean pre-operative Knee Score of 43.8 increased to 77.1 and the mean pre-operative Function Score of 20.3 increased to 63.4 at 5 years. The WOMAC scores also showed marked improvement from pre-operative status after 5 years minimum follow-up: pain 250 pre-op to 157, stiffness 115 pre-op to 56 and function 910 pre-op to 588.
There was no radiographic evidence of loosening or migration. The average American Knee Society Score for each component was 4. Small gaps between the bone-implant interface were observed to heal over the first year. A separate phenomenon of focal osteopenia is also described in a small number of well-fixed femoral components (12 of 219).
To date, 3 prostheses have been revised, 2 due to deep infection and 1 due to tibial tray subsidence. A survivor-ship of 98.6% has been achieved at 8 years.
We believe this to be the first medium term study for the Duracon HA coated knee arthroplasty system, showing excellent clinical and radiographic outcome, with 100% follow-up at 5 to 8 years.
Correspondence should be addressed to: Tim Wilton, BASK, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE.
