Abstract
Minimal Invasive Surgery (MIS) in total knee arthroplasty (TKA) has gained much attention in the scientific community and the public in the last few years. There still exists confusion in the related terminology and different surgical techniques are recommended. Cost effectiveness and risk/benefit analysis are not available at the moment. There still remains controversy whether these new techniques represent only a modern trend or the future of TKA.
MIS Unicondylar replacement has shown significant faster rehabilitation but the same reproducible radiographic and clinical results compared with the conventional open technique. In Oct 2003 we have started using MIS TKA in our hospital. After a significant learning curve the decision was made to do only MIS TKA from Nov. 2004 up to now. More than 300 cases were performed. Only few definite data are available at this stage. In 20% of the patients we performed the so called quad sparing (QS) technique. This offers a less invasive but very demanding and time consuming approach, where most of the surgery has to be performed from the side using complete new side cutting instruments. In the majority of our patients (80%) we performed a modified mini midvastus (MMI) approach, using standard 4 in 1 front cutting instruments. Electromagnetic navigation (EM) might be a helpful tool for MIS surgery in TKA. We have limited experience with this new EM navigation system in combination with the new MIS TKA surgical techniques.
In a pilot study with two groups of patients the direct comparison between QS and MMI was evaluated. Clinical evaluation was performed by two scores (KSS and WOMAC) and five additional functional tests including straight leg raising, active motion, raising a chair, stair climbing and functional gait analysis. Testing was performed pre-op and at 1, 6 and 12 weeks post-op. Patients and investigators were blinded to the surgical technique (either QS or MMI).
The average OR time was 92 min (70 to 130) for MMI and 110 (85 to 165) for QS respectively. There were no complications in the MMI and 1 (wound healing) in the QS group. There were no differences in the different scores and in the functional tests between the groups at any time.
There is still controversy in the benefit-risk analysis for the different minimal invasive techniques. In our hospital the MIS future for TKA has already started. Patients’ satisfaction and significant earlier rehabilitation are the key advantages of these new surgical techniques. The much easier MMI technique is now the standard. Only in selected cases the more demanding QS technique is performed. According to the learning curve these new MIS techniques are for specialized surgeons only and require additional training programmes. Despite these facts, we do believe that MIS is the future of TKA surgery.
The abstracts were prepared by Orah Naor, IOA Co-ordinator and Secretary. Correspondence should be addressed to Israel Orthopaedic Association, PO Box 7845, Haifa 31074, Israel.
