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Long-term follow-up of 173 HA Coated Screw Cup THAs

C. J. Mann, E. J. Taylor. S. McNally. J. A. N. Shepperd

Category: Furlong Clinical Results

From The Conquest Hospital, Hastings, UK

Reports of the results of screw-cup arthroplasties have been disappointing with high revision rates. We reviewed our experience of 173 HA coated screw cups which have been implanted in 150 patients. The average follow up was 6.5 years (range 5- 9 years). The follow up rate was 93%. Patients were followed up at 6 weeks, 3 months, 6 months and 1 year and annually thereafter. The patients were assessed using the Merle D’ Aubigné (MOP) clinical scoring scale and by radiographic review. 2 patients had revision surgery for recurrent dislocation (1.2%). 2 patients were revised for aseptic loosening (1.2%). 1 patient underwent revision surgery due to deep prosthetic infection (0.6%), and 2 patients were revised for polyethylene wear without loosening (1.2%), which gave a total revision rate of 4.0%. The average post operative MOP scores were 5.7 for pain, 5.5 for range of movement and 5.4 for function. Radiological review revealed 1 patient with extensive granuloma formation and 2 patients with evidence of migration although no cups were revised for migration alone. We believe that the lower revision rate in this series is due to the double advantage of an HA coated cup (which leads to low revision rates for aseptic loosening), and the use of a ceramic head (which produces low polyethylene wear rates). We believe our results convey strong evidence for the advantage offered by HA coating for use with a screw-cup or other prosthesis.

Results presented at the Combined New Zealand and Australian Orthopaedic Associations Scientific Meeting, 7 – 12 October 2001, Queenstown, New Zealand