A longitudinal study of the radiolucent line at the bone-cement interface following total joint-replacement procedures.

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.