We reviewed 124 consecutive kinematic condylar total knee replacements
(in ninety-one patients) at two to four years postoperatively. One hundred
and eleven (90 per cent) were rated as good or excellent. The average
active postoperative flexion was 106 degrees (range, 94 to 120 degrees).
Twenty-two knees (18 per cent) had incomplete, non-progressive radiolucent
lines, less than one millimeter in width, at the tibial bone-cement
interface; these were considered insignificant. Restriction of
stair-climbing ability in this series appeared to be a function of
involvement of multiple joints rather than of patellar replacement, as the
rheumatoid patients with resurfaced patellae performed the worst. The
osteoarthritic patients with involvement of a single joint performed the
best, regardless of whether the patella was resurfaced or not. When
compared with a similar series of total knee replacements in which the
tibial component was made entirely of plastic, less reaction at the
bone-cement interface was found with the metal-backed kinematic tibial
component. We suggest that this finding is clinical confirmation of in
vitro studies that demonstrated the advantage of metal-backed tibial
components. We concluded that this procedure, if meticulously performed,
will give predictably good to excellent results with a low complication
rate, a good postoperative range of motion, and a favorable-appearing
bone-cement interface at two to four years.