This study examined the changes in knee alignment after an open wedge high tibial osteotomy before and after weight-bearing. From 2004 to 2006, 36 high tibial osteotomies were performed to treat unicompartmental arthritis with a varus deformity. Thirteen patients without instability and with an accurate radiographic evaluation were included. The changes in the deviation of the mechanical axis and femorotibial angle were evaluated retrospectively using whole extremity radiographs immediately after surgery (supine position) and 4 months after surgery (weight-bearing position). In the nonweight-bearing radiograph obtained immediately after surgery, the mean deviation of the mechanical axis was 22% laterally and the mean femorotibial angle was valgus 8.9 degrees . The weight-bearing radiograph at 4 months after surgery showed that the former shifted laterally 34% and the latter shifted valgus 10.6 degrees . The changes in the mechanical axis and femorotibial angle were significant (P < 0.001). During open wedge high tibial osteotomy, the surgeon should consider the increase in deviation of the mechanical axis and femorotibial angle after weight-bearing.

BackgroundDuring ligament balancing for severe medial contracture in varus knee total knee arthroplasty (TKA), complete distal release of the medial collateral ligament (MCL) or a medial epicondylar osteotomy can be necessary if a large amount of correction is needed.MethodsThis study retrospectively reviewed 9 cases of complete distal release of the MCL and 11 cases of medial epicondylar osteotomy which were used to correct severe medial contracture. The mean follow-up periods were 46.5 months (range, 36 to 78 months) and 39.8 months (range, 32 to 65 months), respectively.ResultsThere were no significant differences in the clinical results between the two groups. However, the valgus stress radiograph revealed significant differences in medial instability. In complete distal release of the MCL, some stability was obtained by repair and bracing but the medial instability could not be removed completely.ConclusionsMedial epicondylar osteotomy for a varus deformity in TKA could provide constant medial stability and be a useful ligament balancing technique.

BackgroundThis study evaluated the preoperative distractive stress radiographs in order to quantify and predict the extent of medial release according to the degree of varus deformity in primary total knee arthroplasty.MethodsWe evaluated 120 varus, osteoarthritic knee joints (75 patients). The association of the angle on the distractive stress radiograph with extent of medial release was analyzed. The extent of medial release was classified into the following 4 groups according to the stage: release of the deep medial collateral ligament (group 1), release of the posterior oblique ligament and/or semimembranous tendon (group 2), release of the posterior capsule (group 3) and release of the superficial medial collateral ligament (group 4).ResultsThe mean femorotibial angle on the preoperative distractive stress radiograph was valgus 2.4° (group 1), valgus 0.8° (group 2), varus 2.1° (group 3) and varus 2.7° (group 4). The extent of medial release increased with increasing degree of varus deformity seen on the preoperative distractive stress radiograph.ConclusionsThe preoperative distractive stress radiograph was useful for predicting the extent of medial release when performing primary total knee arthroplaty.

The objective of this study was to evaluate and compare the biomechanical properties of the Ligament Plate® with other femoral fixation devices. The Ligament Plate® and three different femoral fixation devices were used in fixation of 60 porcine femora and harvested porcine tendons. For each fixation device, a porcine graft-tendon complex was used for the simple load-to-failure test and the load-to-failure test after a cyclic loading test, and the maximal failure load was measured. The amount of graft elongation and failure pattern after the cyclic loading test and load-to-failure test were evaluated. In the BioScrew® group, the mean maximal failure load in the load-to-failure test and load-to-failure test after a cyclic loading test was significantly lower and significant graft elongation was noted. There were no significant differences between the other groups. The Ligament Plate® provided adequate initial fixation power suitable for early rehabilitation.

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Results: The mean operation time of the single vertebral body in group 2 was statistically lower than in group 1(p<0.05). There was more disruption of the medial wall of the pedicle in group 2 than in group 1(p<0.05). In the aspect of the volume of cement injected in the thoraco-lumbar junctional vertebrae, group 2 used significantly less cement than group 1(p<0.05). There were no significant differences in the cement leakage, vertebral height restoration, kyphotic deformity correction, admission time and VAS scores between groups 1 and 2(p>0.05).Conclusion: There were no significant differences in clinical satisfaction and radiological results between the unipedicular and bipedicular kyphoplasty. The advantage of a unipedicular approach is the shorter procedure time than the bipedicular approach. This is particularly useful in multi-level compression fractures. The rate of the unipedicular approach in upper and mid thoracic spine is higher because of the higher convergence of the pedicle and the lower volume of vertebral body despite the disadvantages of instrument insertion through the medial pedicle wall.