Kendoff Daniel, Board Timothy N, Citak Musa, Gardner Michael J, Hankemeier Stefan, Ostermeier Sven, Krettek Christian, Hüfner Tobias
Trauma Department, Hannover Medical School, Carl Neubergstr. 1, 30625 Hannover, Germany.
J Orthop Res. 2008 Apr;26(4):553-61. doi: 10.1002/jor.20510.
Successful outcomes following high tibial osteotomy (HTO) require precise realignment of the mechanical axis of the lower extremity. The inability to accurately assess the weight-bearing axis intraoperatively may account for inappropriate degrees of correction with the osteotomy. We tested the hypothesis that axial loading of the limb affects alignment during an HTO procedure. A custom mechanical load apparatus was developed to simulate weight-bearing conditions intraoperatively. Fixation to the trunk was achieved by supraacetabular pins and an external fixation device, which allowed the pelvis to be rigidly fixed relative to the apparatus while axial load was applied to the foot. Ten fresh cadavers were used for testing. The baseline mechanical axis was determined by a navigation system. HTO was then performed, and varying degrees of valgus correction were obtained and stabilized. For each correction, one quarter, one half, or full body weight was applied axially to the foot, and the axis deviation was measured. Subsequently, the MCL was sequentially released to determine the effect of ligament incompetence. Prior to osteotomy, load application did not produce significant axis deviations. Following osteotomy, the mechanical axis deviation shifted significantly in all trials, increasing as load magnitude and degree of correction increased. With complete sectioning of the MCL, a further significant shift in the axis occurred. Deviations of mechanical axis occur on weight bearing in lower limbs following HTO. These shifts must be considered and possibly quantified to achieve the desired axis correction and maximize the chance at a successful long term outcome.
高位胫骨截骨术（HTO）后的成功结果需要精确调整下肢的机械轴。术中无法准确评估负重轴可能导致截骨术的矫正程度不当。我们测试了这样一个假设，即肢体的轴向负荷会在HTO手术过程中影响对线。开发了一种定制的机械加载装置，以在术中模拟负重情况。通过髋臼上的钢针和外部固定装置实现与躯干的固定，这使得在对足部施加轴向负荷时，骨盆能够相对于该装置牢固固定。使用十具新鲜尸体进行测试。通过导航系统确定基线机械轴。然后进行HTO，并获得不同程度的外翻矫正并使其稳定。对于每次矫正，分别向足部轴向施加四分之一、二分之一或全身重量，并测量轴偏差。随后，依次松开内侧副韧带（MCL）以确定韧带功能不全的影响。在截骨术前，施加负荷不会产生明显的轴偏差。截骨术后，在所有试验中机械轴偏差均显著偏移，且随着负荷大小和矫正程度的增加而增加。当MCL完全切断时，轴发生进一步的显著偏移。HTO后下肢负重时会出现机械轴偏差。必须考虑这些偏移并可能进行量化，以实现所需的轴矫正并最大限度地提高长期成功结果的机会。
