A RANDOMISED CLINICAL TRIAL COMPARING FIVE-YEAR CLINICAL AND RADIOGRAPHIC OUTCOME OF HYDROXYLAPATITE VERSUS CEMENTED TIBIAL FIXATION IN PRIMARY TOTAL KNEE ARTHROPLASTY

Abstract

We compared self-reported pain and function, complications and revision rates, and radiographic outcomes of hydroxylapatite(HA) or cemented tibial fixation in the first five years following primary total knee arthroplasty. This was a randomised clinical trial of eighty-one patients

Prospective, randomised clinical trial. Patients less than seventy years of age with non-inflammatory knee arthritis. Eighty-one patients were randomised at the time of surgery to receive HA or cemented tibial fixation. Subjects were evaluated preoperatively, six months, one and five years postoperatively by a physical therapist who was blinded to group allocation. X-rays were evaluated by an experienced arthroplasty surgeon who did not perform any of the surgeries. Self-reported pain and function, the primary outcomes, were measured by the Western Ontario McMaster (WOMAC) Osteoarthritis Index and the RAND 36-item Health Services Inventory (RAND-36). Complications and revision rates were determined through hospital record review and at each patient evaluation. The Knee Society Radiological Score was used to evaluate plain radiographs at each assessment.

There was slightly more pain in HA group at six months as measured by both the WOMAC and RAND-36, a difference that disappeared by the one-year assessment. There were no differences in function, radiographic findings or complications at any time. Finally, no subjects required revision of the tibial prosthesis during the study.

Overall, no significant differences were seen between groups. The initial difference in self-reported pain disappeared by twelve-months postoperatively. At five-years postoperatively, there is no advantage to HA tibial fixation over cemented tibial fixation.