Early radiographic results comparing cemented and cementless total hip arthroplasty.

In a randomized clinical trial of cemented and cementless total hip arthroplasty, 147 patients (76 cemented, 71 cementless) have had a minimum 4-year clinical and radiographic follow-up evaluation. No revisions have been done in either group. Two cemented acetabular components were considered definitely loose and 18 were probably loose; 7 cemented stems were possibly loose at last follow-up examination. One cementless socket was considered unstable. Although cementless femoral component subsidence occurred in 10 cases, the sinkage always stabilized within 6 months, and no stem was considered unstable at last follow-up examination. Significant femoral bone resorption was rare, and so-called "spot welds" were uncommon using this titanium stem. Distal cortical hypertrophy was common, but the cause is uncertain. Osteolysis was seen around 10 cementless and 6 cemented sockets. A small area of lysis occurred in the proximal medial femoral neck in 15 cemented stems and 1 cementless stem. No cases of distal femoral lysis were seen in either group. Despite excellent clinical results with no difference between groups, the high rate of early radiographic failure of this metal-backed acetabulum should preclude its use. Osteolysis will continue to be a problem in both groups, and its prevention should remain the focus of future studies.