CLINICAL RESULTS OF TOTAL KNEE ARTHROPLASTY BY USING IMPROVED CEMENT TECHNIQUE BY INTERPOSING HYDROXYAPATITE GRANULES

Abstract

Improved cement technique by interposing less than two layers of hydroxyapatite (HA) granules between bone and bone cement at the cementing (Interface Bio-active Bone Cement : IBBC) have been performed in total knee arthroplasty (TKA) since 1987.

We performed IBBC technique in 153 knees (130 patients) in TKA from 1987 to 1993. One hundred and forty knees (120 patients) could be followed up clinically and radiologically. Follow up rate was 91.5%. A mean follow-up period was 9.5 years (6 to 13 years) after surgery. As a control, clinical results of TKA with conventional cementing (Non-IBBC) which were operated in 44 knees (44 patients) in 1986 were used.

In IBBC cases, radiolucent lines on the tibial components were seen 7.1%, 2.9%, 1.4%, 3.6%, 0%, 0% and 0% at Zone ‡T to ‡Z of the anteroposterior view, while in Non-IBBC cases, 40.9%, 13.6%, 9.1%, 27.3%, 11.4%, 4.5% and 13.6% at Zone ‡T to ‡Z, respectively. In IBBC cases peri-prosthetic osteolysis of the tibial components were seen in three knees (2.1%), while 29.5% in Non-IBBC cases. Aseptic loosening of the tibial component was only one case (0.7%) in IBBC cases, while 9.1% in Non-IBBC cases.

In IBBC, bone cement bound to HA mechanically immediately after surgery and HA granules bound to the bone physicochemically after bone ingrowth into the spaces around the HA granules. In Non-IBBC, spaces will appear between bone and bone cement due to osteoporosis and/or atrophy after long years. However, in IBBC, bone and bone cement will contact by interposing HA forever due to osteoconductive effect of HA.

In conclusion, the IBBC has significantly reduced the incidence of radiolucent lines and periprosthetic osteolysis in TKAs. IBBC is a method combining the advantage of cementless HA coating and bone cement.