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

      To the Editor:
      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.
      • Lee Y.S.
      • Lee B.K.
      • Kwon J.H.
      • et al.
      Serial assessment of weight-bearing lower extremity alignment radiographs after open-wedge high tibial osteotomy.
      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.
      • Lee Y.S.
      • Lee B.K.
      • Kwon J.H.
      • et al.
      Serial assessment of weight-bearing lower extremity alignment radiographs after open-wedge high tibial osteotomy.
      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.
      • Luo C.A.
      • Hua S.Y.
      • Lin S.C.
      • Chen C.M.
      • Tseng C.S.
      Stress and stability comparison between different systems for high tibial osteotomies.
      • Agneskirchner J.D.
      • Freiling D.
      • Hurschler C.
      • Lobenhoffer P.
      Primary stability of four different implants for opening wedge high tibial osteotomy.
      Brinkman et al.
      • Brinkman J.M.
      • Luites J.W.
      • Wymenga A.B.
      • van Heerwaarden R.J.
      Early full weight bearing is safe in open-wedge high tibial osteotomy.
      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.
      • Pape D.
      • Lorbach O.
      • Schmitz C.
      • et al.
      Effect of a biplanar osteotomy on primary stability following high tibial osteotomy: A biomechanical cadaver study.
      Figure thumbnail gr1
      Fig 1Top, TomoFix plate. Bottom, TomoFix small. Holes A through C and 3 and 4 are for 5.0 locking screws. Holes D, 1, and 2 are locking compression holes for 4.5/5.0.
      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).
      • Staubli A.E.
      • De Simoni C.
      • Babst R.
      • Lobenhoffer P.
      TomoFix: A new LCP-concept for open wedge osteotomy of the medial proximal tibia—Early results in 92 cases.
      The biplanar ascending cut should be at an angle of 110° to the transverse cut without bone graft.
      Figure thumbnail gr2
      Fig 2Anteroposterior-view radiograph of left knee after open-wedge HTO without bone graft in a biplanar technique at 6 months' follow-up.

      References

        • Lee Y.S.
        • Lee B.K.
        • Kwon J.H.
        • et al.
        Serial assessment of weight-bearing lower extremity alignment radiographs after open-wedge high tibial osteotomy.
        Arthroscopy. 2014; 30: 319-325
        • Luo C.A.
        • Hua S.Y.
        • Lin S.C.
        • Chen C.M.
        • Tseng C.S.
        Stress and stability comparison between different systems for high tibial osteotomies.
        BMC Musculoskelet Disord. 2013; 14: 110
        • Agneskirchner J.D.
        • Freiling D.
        • Hurschler C.
        • Lobenhoffer P.
        Primary stability of four different implants for opening wedge high tibial osteotomy.
        Knee Surg Sports Traumatol Arthrosc. 2006; 14: 291-300
        • Brinkman J.M.
        • Luites J.W.
        • Wymenga A.B.
        • van Heerwaarden R.J.
        Early full weight bearing is safe in open-wedge high tibial osteotomy.
        Acta Orthop. 2010; 81: 193-198
        • Pape D.
        • Lorbach O.
        • Schmitz C.
        • et al.
        Effect of a biplanar osteotomy on primary stability following high tibial osteotomy: A biomechanical cadaver study.
        Knee Surg Sports Traumatol Arthrosc. 2010; 18: 204-211
        • Staubli A.E.
        • De Simoni C.
        • Babst R.
        • Lobenhoffer P.
        TomoFix: A new LCP-concept for open wedge osteotomy of the medial proximal tibia—Early results in 92 cases.
        Injury. 2003; 34: B55-B62

      Linked Article

      • Serial Assessment of Weight-Bearing Lower Extremity Alignment Radiographs After Open-Wedge High Tibial Osteotomy
        ArthroscopyVol. 30Issue 3
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          The purpose of this study was to perform a serial assessment of the radiologic parameters of the mechanical axis (MA) and the weight-bearing line (WBL) using a weight-bearing anteroposterior (AP) long-standing view of the lower extremity to determine whether the postoperative MA and WBL change with time.
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      • Author's Reply
        ArthroscopyVol. 30Issue 9
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          We read the letter to the editor by Schröter and Ateschrang with great interest and thanks for their thoughtful consideration and questions about our article “Serial assessment of weight-bearing lower extremity alignment radiographs after open-wedge high tibial osteotomy.” They mentioned the TomoFix plate in relation to our figures and methods. First, we are in agreement with them about the TomoFix: 6.5-mm screws cannot be used in holes A through C and holes 3 and 4. Second, the materials for this study were collected retrospectively and from multiple centers from 2007 to 2011.
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