Abstract
In June 1999 we instituted a prospective, randomised, double blind study to determine whether in the use of the Profix® total knee replacement system the addition of screws improved the fixation of the tibial base plate. There were 145 arthroplasties in 137 patients, 77% of them female. Their mean age was 66 years. In 86% of the patients there was osteoarthritis and in 14% an inflammatory arthritis. On a random basis, supplementary screws were inserted through the base plate into the tibia in 49% of arthroplasties and the remaining 51% were not fixed. In both groups the postoperative femoral angle measured 95% and at 12-month evaluation the tibial angle measured 89°, giving a total valgus angle of 6°. To date no tibial base plates have come loose. It is felt that the large central titanium peg plays a major role in assisting fixation of the base plate to the tibia and that supplementary screws are unnecessary. There is a small cost saving when screws are not used. We postulate that one may in the future minimise polyethylene debris tracking and osteolysis.
The abstracts were prepared by Professor M. B. E. Sweet. Correspondence should be addressed to him at PO Box 47363, Parklands, Johannesburg 2121, South Africa.
