Critical Comments and Questions Regarding the Article “Serial Assessment of Weight-Bearing Lower Extremity Alignment Radiographs After Open-Wedge High Tibial Osteotomy”

It was with great interest that we read the article “Serial assessment of weight-bearing lower extremity alignment radiographs after open-wedge high tibial osteotomy” by Lee et al. in the March 2014 issue of Arthroscopy. We have some comments and questions regarding the methods, figures, discussion, and conclusions.

The authors described in the Methods section how they used the TomoFix plate (DePuy Synthes Raynham, MA) and 6.5 mm screws for fixation. First, all figures (Figs 1, 2 and 3 in their article) show different plates. We think that Fig 1 in their article shows a 4.5/5.0 T-plate with nonlocking screws; Figs 2 and 3 in their article show a totally different plate, which is not a TomoFix plate (it has 4 holes in the proximal part and 4 in the distal part, and the shape of the proximal T-part is straight). Second, if one uses the TomoFix plate, using a 6.5 screw would not be possible in holes A through C and holes 3 and 4 (Fig 1). These holes are locking holes for a 5.0 locking screw. The TomoFix plate was developed for a special biplanar surgical open-wedge HTO technique. Why did Lee et al. perform a single-plane technique? Which plates did they use in their study? Different plates? Again, they described the TomoFix for fixation, and in the figures, they showed 2 different plates. Can the authors explain that? They described a loss of correction after open-wedge HTO, but in the Discussion section, there was no explanation of that finding. Could it be possible that they used nonlocking screws and not the TomoFix plate but a different plate? If so, their observation is understandable. The stability of the fixation depends on the implant. Different biomechanical studies describe how important the fixation system is for stability.^,  Brinkman et al. described in a radiostereometric analysis that early full weight bearing is possible with the TomoFix plate without loss of correction. For nonlocking plates with less stability, a biplanar technique would be an advantage.

Therefore we do not agree with the conclusion. We suggest that the following statement would be more correct: “The WBL shifts after open-wedge HTO in a single-plane technique using nonlocking screws and bone graft in the first year medially.”

We recommend the use of a locking compression plate (TomoFix, Solothurn, Switzerland) in conjunction with 5.0 locking screws with the modified technique described by Staubli et al. (Fig 2). The biplanar ascending cut should be at an angle of 110° to the transverse cut without bone graft.