COMPUTER ASSISTED ALIGNMENT OF THE OXFORD UNICOMPARTMENTAL KNEE ARTHROPLASTY- THE KINGSTON EXPERIENCE WITH TWO TECHNIQUES

Abstract

Two computer assisted techniques (CT and a fluoro-guide based system) were used to insert the femoral component of the Oxford Unicompartmental Knee arthroplasty. The accuracy and variability of component positioning were compared. Clinical data was collected pre-operatively and is being collected post-operatively. Standing AP and lateral knee X-rays as well as skyline X-rays were collected pre-operatively and post-operative full length AP and lateral femur X-rays were completed in order to measure alignment of the femoral component. Results are showing accurate insertions of the Oxford knee femoral component using both systems.

To review two computer-assisted techniques for inserting Oxford Unicompartmental Knee arthroplasties. CT based and fluro based techniques were compared with regards to accuracy and variability of component positioning.

Currently we are able to use either a CT based system or a fluro based system to accurately insert the femoral component of the Oxford Unicompartmental Knee arthroplasty.

Computer assist techniques are allowing us to perform minimally invasive arthroplasty procedures with great accuracy.

Patients were all seen in a pre-admission clinic where pre-operative clinical survey data were collected. All patients had standing AP and lateral knee X-rays as well as skyline X-rays pre-operatively. Post-perative full length AP and lateral femur X-rays were completed in order to measure alignment of the femoral component. Patients are being followed post-operatively with SF-36, WOMAC, Knee Society Scores, and X-rays. Patients being operated on with the CT based system had pre operative CT scans. Intra-operatively a DRB was fixed to the patient’s femur and the chosen computer assisted technique was used to direct the rotation of the tibial cut as well as the alignment of the femoral cutting jig. To date we have completed seventeen computer assisted Oxford Unicompartmental Knee Arthroplasties. The average error in the AP plane using CT based system was 3.2 degrees and 2.1 degrees for the lateral plane. The average error in the AP plane using the fluro-based system was 2.2 degrees and 1.3 degree for the lateral plane.

Funding: NSERC, IRIS, ORDCF