TWO-YEAR FOLLOW-UP OF A COMPARATIVE STUDY OF MINIMALLY INVASIVE COMPUTER ASSISTED TOTAL KNEE ARTHROPLASTY (MICATKA) VERSUS CONVENTIONAL COMPUTER ASSISTED TOTAL KNEE ARTHROPLASTY (CATKA)

Abstract

Minimally invasive total knee arthroplasty is growing in popularity. It appears to reduce blood loss, reduce hospital stay, improve post-operative quadriceps function and shortens post-operative recovery. We show our experience of minimally invasive TKA with a computer navigation system.

Forty patients who underwent MICATKA were compared with forty patients having conventional CATKA. Component positioning was assessed radiographically with AP long leg standing views. Knee Society Scores, length of stay and recovery of straight leg raise was also recorded pre-operatively and at 6, 12, 18 and 24 months.

Pre-operative Knee Society Scores showed no significant difference between the two groups. Post operatively the mean femoral component alignment was 89.7 degrees for MICATKA and 90.2 for CATKA. The mean tibial component alignment was 89.7 degrees for both. Knees society scores at 6, 12, 18 and 24 months were statistically better in the MICATKA (p< 000.1). However the mean difference in Knee Society Scores had fallen. Straight leg raise was achieved by day one in 93% of the MICATKA compared to only 30% of the CATKA. Length of stay for MICATKA was a mean of 3.25 days with CATKA a mean of 6 days.

MICATKA is a safe procedure with reproducible results. Alignment is equivalent to CATKA. It gives statistically significant improvement in Knee Society Scores compared to the open procedure. The length of stay and time to straight leg raise is also reduced. At a minimum of 2 years follow-up we have seen no revisions and no evidence of radiographic loosening. A randomised multi centre trial is under way and early results are awaited.