Abstract
Purpose of Study: Fixed bearing unicompartmental knee replacement (UKR) has become popular since several series have shown good 10 year survivorship and excellent function. However little is known about survival during the second decade.
Method: From the Bristol database of over 4000 knee replacements 203 St. George Sled UKR’s which had already survived 10 years were identified. The mean age at surgery was 67 years (48–85), with 64% being female. This cohort has been further reviewed at an average of 14.8 years (10–30) from surgery to determine survivor-ship and function.
Results: Survivorship during the second decade was 87.5%. 58 patients (69 knees) had deceased with implant in situ, only 2 after revision. A further 15 UKR’s have been revised at an average of 13 years post op; 7 for progression of disease, 4 for tibial loosening, 3 for polyethylene wear, 2 for femoral component fracture and 2 for infection.
99 knees were followed for 15 years and 21 knees for 20 years. The average Bristol knee score of the surviving knees fell from 86 to 79 during the second decade.
A previous study showed an 89% 10 year survivor-ship and this is now extended to 82% at 15 years and 76.5% at 20 years.
Conclusion: Satisfactory survival of fixed bearing UKR can be achieved in the second decade suggesting that the indications for mobile bearings require careful definition since there is a higher incidence of complications in many people’s hands.
Correspondence should be addressed to Mr Tim Wilton, BASK at the Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE.
