Abstract
The main purpose of our study was to evaluate medial meniscal extrusion (MME) before and after medial opening wedge high tibial osteotomy. We have to compare the same situation before and after surgery. We decided to do that using magnetic resonance imaging (MRI) with the same protocol before and after surgery. This includes an extended knee using the method described by Hada et al 1 to measure the MME. Unfortunately, we cannot measure this with weightbearing according to the available MRI we have. I am sure it would be the best option, but most importantly, we compared the same situation before and after surgery, which is one of the reasons why we decided to evaluate functional and clinical scores, trying to find a correlation between images and clinical status.
The study by Roos et al 2 described the Knee injury and Osteoarthritis Outcome Score, which may be useful in evaluating the course of knee injury with and without treatment. You are completely right in that the study by Roos et al 2 was incorrectly cited with respect to the MME measurement technique.
According to our study, all medial opening wedge high tibial osteotomies were performed using the same surgical technique. We only have a single main variable: the plate used (Puddu or TomoFix). However, we did not find any significant differences between them.
Finally, we agree that there was an effect regarding knee flexion. Recently, we concluded a cadaveric biomechanical study correlating knee flexion with contact area and pressure between the femur and the tibia with different MME values. There are significant differences in these variables according to area and pressure, which means we probably have different values if we measure the MME in different ranges of motion. However, it was not possible to evaluate all knee flexion angles in our patients before and after surgery. Therefore, we decided to do all measurements with the knees extended. We believe that what is most important is to compare the same conditions before and after surgery.
MME studies are complex because we have many possible confounding variables. We tried to compare the most homogeneous sample we could to find the most precise results.
Footnotes
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