Long-term results of the threaded Weill cup in primary total hip arthroplasty: a 15-20-year follow-up study

Abstract

Uncemented, threaded acetabular components with smooth surface treatment were widely used in continental Europe in the 1970s and 1980s for primary total hip arthroplasty (THA). Previously published studies showed high failure rates in the mid-term. In a consecutive series of 116 patients, 127 threaded cups with smooth surface treatment (Weill cup; Zimmer, Winterthur, Switzerland) were implanted in combination with one type of uncemented stem. Patients were followed up clinically and radiographically. Mean time of follow-up was 17 years (range 15-20). At the time of follow-up, the acetabular component had been revised or was awaiting revision in 30 hips (24%). Two hips were revised for infection and 23 for aseptic loosening. Four polyethylene liners were exchanged because of excessive wear. One hip was awaiting revision. The survival rate for all acetabular revisions including one hip awaiting revision was 75% (95%CI: 65-85%) at 17 years. These results support the view that smooth, threaded acetabular components do not provide satisfactory long-term fixation and should be abandoned. It is important to closely monitor patients with these components as the failure rate remains high in the long-term.

Fig. 1

Smooth threaded Weill acetabular cup (Zimmer, Winterthur, Switzerland)

Fig. 2

Distribution of hips with Weill cup at a minimum follow-up of 15 years

Fig. 3

Kaplan-Meier survivorship curve for all revisions including hips awaiting revision as the endpoint. The 17-year survival rate was 75% (95%CI: 65–85%)

Fig. 4

Postoperative radiograph after implantation of the Weill cup (Zimmer, Winterthur, Switzerland) in a 52-year-old man with primary osteoarthritis (left). Acetabular loosening with fixation failure and massive bone loss ten years postoperatively (right). The patient only noticed leg length discrepancy