Abstract
Introduction: This study investigates the survival (and radiological loosening) rates of prostheses following uncemented Total Shoulder Arthroplasties (TSAs) focusing on the glenoid baseplate fixation.
Methods: ALL uncemented TSAs inserted in one shoulder unit from 1989 to 2001 were entered onto a database prospectively and the patients monitored to death or failure of the implant, resulting in revision surgery. Over 80% of the surviving implants were monitored on sequential radiographs and the radiological loosening rate was observed. 273 TSAs have been monitored – 193 with a porous coated glenoid baseplate and 80 with a hydroxyapatite coating on top of the porous coating.
Results: The Survival rates (%) of the non-HA coated baseplates at 1 to 12 years using the Life Table Method were:− 97, 93, 89, 83, 83, 81, 79, 79, 77, 75, 75 & 75% respectively. The Survival rates for the HA coated glenoid base-plates at 1 to 4 years were 100, 97, 93, & 93% respectively. Failures were predominantly due to mechanical loosening and glenoid disassembly with only 3 cases of infection documented. Thus by 4 years there was a statistically significant improvement in survival of the glenoids. Survival rates were further reduced when radiological loosening was taken into account. The earlier series was analysed to assess the survival of prostheses inserted for RA and OA. The survival rates at 5 and 10 years were 78% & 70% for OA and 96% and 88% for RA.
Discussion & Conclusions: This Life Table analysis confirms the early benefit from the use of hydroxy-apatite coating of the glenoid implant of a TSA. Further improvements, particularly in relation to reducing further the small risk of disassembly are underway.
Correspondence should be addressed to Carlos Widgerowitz, Honorary Secretary BORS, Division of Surgery and Oncology, Section of Orthopaedic and Trauma Surgery, Ninewells Hospital and Medical School, Tort Centre, Dundee DD1 9SY, Scotland.
