FAILURE OF A NON-POROUS-COATED ACETABULAR COMPONENT INSERTED WITHOUT CEMENT IN PRIMARY TOTAL HIP-ARTHROPLASTY

Thirty-four patients (thirty-eight hips) had a primary total hip arthr oplasty with insertion of a non-porous-coated titanium-alloy acetabula r component without cement, This component is initially stabilized wit h use of a central acetabular polyethylene peg, which is inserted into the pelvis, as well as supplementary cortical-bone screws inserted in to the ilium. The original diagnosis was degenerative joint disease in thirty-four hips and avascular necrosis in four hips, Twenty-five fem oral components were inserted with cement, and thirteen non-porous-coa ted femoral implants were inserted without cement, The acetabulum was prepared with so-called line-to-line reaming, Thirty-five hips in thir ty-one patients were available for clinical and radiographic follow-up at a mean of 4.5 Sears (range, two to seven years), Serial measuremen ts of the position of the acetabular component revealed that eighteen cups (51 per cent) had migrated, Of these, eleven had been revised, Ra diolucent lines of at least one millimeter in thickness at the bone-pr osthesis interface were noted adjacent to all but six of the acetabula r components, Although this series was small, it demonstrates an unacc eptably high rate of failure of non-porous-coated acetabular component s after a relatively short duration, We question the efficacy of this acetabular component, inserted without cement, as part of a primary to tal hip arthroplasty.