BILATERAL SIMULTANEOUS MEDIAL OXFORD UNICOMPARTMENTAL KNEE REPLACEMENT USING THE MINIMALLY INVASIVE APPRAOCH.

Abstract

Purpose: To evaluate the feasibility and short term outcomes of bilateral medial unicompartmental replacement, undertaken with the patient positioned to allow simultaneous procedures in a safe and appropriate fashion.

Methods: The use of the minimally invasive approach for implantation of the Oxford unicompartmental replacement (Biomet, UK) has become increasingly popular over the past few years, though this requires a specific knee positioning for optimal implantation to allow the leg to remain dependant and a full range of flexion.

We describe a previously unreported method of positioning to allow bilateral procedures.

Fifteen patients have undergone bilateral medial unicompartmental replacements (ie 30 knees), using the minimally invasive approach, with our appropriate positioning technique.

Early results in terms of complications, post-operative radiographs and Oxford knee score were noted. A comparison with groups of an age and sex-matched bilateral total knee replacement group and a group of single unicompartmental knees was also undertaken.

Results: The mode of patient positioning for the bilateral procedure is described

There were no noted complications in the operative or early post-operative periods. Review of the radiographs demonstrates 4 minimally malpositioned implants with no symptomatic correlation. In early follow, from 6 months to 2 years, there has been 1 moderate result, with a patient requiring an MUA for 1 knee. 12 of 15 patients report good or excellent post-operative results in both knees. Three patients report problems with 1 knee only. The age matched group of bilateral total knee replacements had longer hospital stays, greater blood transfusion requirements and minor post-operative complications. There were a similar number of radiographic abnormalities and 1 re-operation in the single unicompartmental group.

Conclusion: It is possible to safely undertake bilateral simultaneous Oxford unicompartmental knee replacements using a minimally invasive technique using our described method, with obvious benefits for patients with symmetrical knee arthrosis. (299 words)