Abstract
Introduction
Kneeling ability is better in unicompartmental than total knee arthroplasty. There is also an impression that mobile bearing knees achieve better functional outcome than their fixed bearing cousins in unicompartmental and to a lesser extent total joint arthroplasty. In the UK, the market leading unicompartmental replacement is mobile bearing.
Aim
To analyse kneeling ability after total and unicompartmental knee replacement using mobile and fixed bearing inserts.
Methods
In our department there are two prospective randomised studies (fixed versus mobile) in this area. For total knee arthroplasty, 207 TKR patients receiving the same prosthesis (Rotaglide, Corin, UK) were randomised into mobile bearing (102 patients, mean age of 53 years) or fixed bearing (105 patients, mean age of 55 years). Regarding unicondylar knees, data was collected on 352 UKR patients who received the same implant (Uniglide - previously known as AMC - Corin, UK). Within this group there was a randomised controlled trial of fixed v mobile bearings: 52 patients (mean age 62 years) had a mobile insert and 57 (mean age 65 yrs) had a fixed insert. Data was also collected on patients undergoing fixed bearing lateral unicondylar replacement (Uniglide). All patients completed the Oxford Knee Questionnaire preoperatively, 1 year and 2 years postoperatively, (where 0 = bad and 48 = good). There kneeling ability (question 7) and total Oxford scores were analysed.
We are currently collecting objective data on post-operative kneeling ability with force plate analysis and subjective anterior knee-specific scoring systems.
Results
Subjective kneeling ability: Oxford Knee Score Question 7 as range 0-4, where 4 = good.
Conclusion
Both fixed and mobile UKR and TKR have good outcome. No group produced good kneeling ability, but there was a modest improvement in all groups from the preoperative kneeling scores. Fixed bearing knee replacement showed better outcome than mobile bearing knees, in both UKR and TKR groups.
