Early Outcomes of Modified Technique of Mobile Bearing Unicondylar Knee Replacement.

Background: Recent years have seen a resurgence in utilization of partial knee replacement. One such device frequently used is Oxford partial knee implant (OPK). Deeper tibial bone cut while performing OPK replacement may risk early failure.

Methods: We prospectively looked at early outcomes of a modified technique (MT) of OPK replacement adopted by our centre to save tibial bone stock at 24 months of follow up as compared to designer group described technique (DT) as a prospective cohort.

Results: At 2 years follow up New Knee Society Score showed patient satisfaction (38.25 in DT vs 39.02 in MT, p value 0.10), objective (92.77 in DT vs 91.07 in MT, value 0.21), expectation scores (14.77 in DT vs 14.85 in MT, value 0.81) and activity (60.72 in DT vs 68.17 in MT, value 0.79 were similar in MT group as compared to DT. The stair climbing ability (22.46 in MT vs 29.96 in DT, value < 0.001) and getting up from chair (13.16 in MT vs 19.80 in DT, value < 0.001), was better with MT group but most other patient performance scores were similar as assessed by DOP (Delaware Osteoarthritis Profile). Both groups had failure rate of 5% at 24 months follow up.

Conclusion: MT resulted in similar early outcomes in terms of patient reported outcomes, satisfaction and performance as compared to DT group. The MT to save tibial bone stock did not compromise early outcomes and can be utilised in certain patients with higher risk of tibial failure.