Abstract
Currently available uncemented acetabular components appear to provide very reliable fixation for at least 10 years. However, these cups have been associated with a significant incidence of polyethylene wear. Osteolysis associated with this wear is emerging as the most significant problem in total hip replacement surgery. The purpose of this presentation is to describe the rationale for reducing polyethylene wear through the use of an uncemented acetabular component made of a polyethylene/ Tantalum (Trabecular Metal) composite and to describe the initial clinical experience with this cup.
Clinical and radiographic data were prospectively collected on the first 125 consecutively performed total hip replacements in which a tantalum (Trabecular Metal), monoblock acetabular component was used. Minimum follow-up was 24 to 46 months. Sixty three percent of the patients were female. Mean age was 61. The diagnoses were: OA-74%; AVN-12%; RA-10%; other-4%. 50% of the hips had cemented femoral components. 20% of the patients were Charnley Class 1, 30% Charnley Class 2, and 50% Charnley Class 3. At most recent follow-up, all patients were pain free (Ave. pain score pre-op.- 6.7, post-op.-1.4). No patient’s function was limited by hip function (Ave. Harris hip score pre-op.-38, post-op.-92). All hips had radiographic findings consistent with bone-ingrowth. Gaps in zone 2 were seen in 10% of hips, but filled in by one year. The rate of polyethylene wear as measured by the Martel technique was less than 0.07mm/year in the first two years.
There were three complications in the group: 2 dislocations which re. The early experience with the monoblock, tantalum cup indicates that initial fixation is secure, even without screws, and that initial polyethylene wear is very low.
The abstracts were prepared by Nico Verdonschot. Correspondence should be addressed to him at Orthopaedic Research Laboratory, University Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
