After 100 consecutive total hip arthroplasties, a radiolucent line at
the bone-cement interface as seen on serial roentgenograms was on the
acetabular side in fifty-nine hips and on the femoral side, in three.
Similarly, after seventy-five consecutive non-hinged knee-replacement
arthroplasties, a radiolucent line was found at the bone-cement interface
beneath the polyethylene component more frequently in knees in which the
more constrained geometric implant was used (forty-two of fity-nine) than
in knees in which the less constrained polycentric and modular prostheses
were used (three of sixteen). The presence of a lucent line at the
bone-cement interface in these joints did not signify looseness or failure
of the arthroplasty.