Five-year follow-up of minimally invasive computer assisted total knee arthroplasty (MICATKA) versus conventional computer assisted total knee arthroplasty (CATKA) - A population matched study.

BACKGROUND: Minimally invasive surgery (MIS) has perceived advantages in the early post-operative stage such as reduced blood loss, decreased pain, earlier return to function and earlier discharge. The aim of our study was to confirm that longer term clinical outcome of TKA is not compromised when MIS is combined with computer assisted surgery. METHODS: Eighty patients matched for age, gender, pre-operative Knee Society Score (KSS) and mechanical axis were prospectively studied. Forty patients underwent minimally invasive computer assisted total knee arthroplasty (MICATKA) and 40 patients underwent conventional computer assisted TKA (CATKA). Functional scores were determined at 6 weeks, 6, 12, 18, and 24 months and 5 years post-surgery. Long-leg alignment views were obtained 3 months post-operatively. RESULTS: KSSs in the short term were significantly better in the MICATKA group than in the CATKA group (p<000.1). Tourniquet-time was 58 min in the MICTKA group and 60 min in the CATKA group (p=0.3). Straight leg raise was achieved by day one in 93% of the MICATKA group compared to 30% of the CATKA group (p<0.001). Length of stay for the MICATKA group has a mean of 3.25 days and a mean of 6 days for the CATKA group (p<0.001). KSSs up to 2-years were significantly better in the MICTKA group (p<0.001). At 5-years there was no significant difference in KSSs (p=0.46) in the MICATKA and CATKA groups. CONCLUSION: We confirm that the use of navigation in minimally invasive TKA permits a number of early post-operative advantages and that longer-term functional outcome is not compromised with its usage. LEVEL OF EVIDENCE: Level II.