SURVIVAL OF UNCEMENTED SHOULDER ARTHROPLASTY

Abstract

This paper reports two studies of uncemented (UC) shoulder arthroplasty – one directed at UC humeral stems (Study 1) and the second at UC glenoid components (Study 2).

In Study 1, 160 consecutive UC humeral stems were inserted between 1989 and 1995. Three types of stem were used – Biomodular, modified Biomodular and Nottingham. At a mean follow-up of 4.3 years 18 shoulders were lost to follow-up. Of the remaining 142 shoulders radiographs from routine follow-up appointments at 6 months,1,2,3,5,7 & 9 years were reviewed together with a clinical follow-up of the patients.

In Study 2 a survival analysis was carried out on a consecutive series of 222 UC glenoid components inserted between 1989 and 1998 at a mean follow-up of over 5 years. Survival was defined as a prosthesis remaining in situ in a live patient. Six types of UC glenoid component were used – Copeland/Zimmer(non HA), stndard Biomodular, low-profile Biomodular, Nottingham prototype, Nottingham and Nottingham with HA.

In Study 1, radiological follow-up indicated 3 stems(2%) showed definite loosening (all related to deep infection) – all were revised. Six stems (4%) showed probable loosening but were asymptomatic.

In Study 2, for the whole series a survival table was created which identified a survival at 2; 5 and 10 years respectively of 92%; 75% and 66%. The later prosthesis designs performed best. A radiological analysis of all shoulders is currently in progress. This audit of outcome has indicated that hydroxyapatite has been beneficial but further long-term studies are required.