[Total hip replacement from a MIS-AL approach (comparison with a standard anterolateral approach)]

Minimally invasive surgery (MIS) techniques have recently become a powerful and effective marketing instruments that are often perceived by the patient as the criterion of the surgeon's and institution's standard. In addition to studies reporting the benefits of minimally invasive procedures, some authors have recently found no such benefits or even pointed out some disadvantages. In this paper we present our own view of this issue. Our definition of minimally invasive surgery: a minimally invasive procedure is such that an optimally placed incision using anatomical intervals without damage to muscle insertions allows us to gain a good view of the operating field and to safely perform the planned surgery. Because of this optimal approach it is possible to make skin incisions shorter.

Between April 21, 2005, and December 28, 2006, the first 40 MIS hip procedures were performed at the Department of Orthopaedic Surgery of the ILF Bulovka. Forty patients who, in the same period, were operated on from an anterolateral standard approach and who met the same indication criteria, including age, comprised a control group. In both groups all routinely used types of implants were included.

For objective assessment of potential differences between surgical outcomes of the two techniques, the following para- meters were recorded: operating time, peri-operative blood loss, pre- and post-operative Hb levels, Hb level on the first post- operative morning, amount of blood drained away with a Redon drain, number of anodyne applications (indirect evaluation of post-operative pain) and length of hospital stay. The parameters were compared for the cemented and the uncemented implants separately. The results were evaluated using the paired t-test, with the significance level set at a value of p<0.05.

A comparison of the MIS-AL results with those of the standard total hip replacement procedure did not show any significant differences, not even during further follow-up; by the end of 2008 no implant failure or necessity of revision arthro- plasty was reported.

So far the only indisputable fact is that all the benefits of minimally invasive techniques described until now are merely related to time, as they facilitate a faster rate of soft tissue repair; therefore, these techniques only shorten recovery and thus speed up return of the operated hip to full function.

Based on comparison of the standard anterolateral and minimally invasive techniques it can be concluded that the MIS- AL approach is effective even without the use of special instrumentation. However, the results of this study failed to give unambiguous support to its advantage over the classical technique.