No correction angle loss with stable plates in open-wedge high tibial osteotomy

The aim of this study was to compare the clinical and radiological results of the wedge plate and locking plate systems in open-wedge high tibial osteotomy. Between 2007 and 2010, the wedge plate was used as the fixation device for osteotomy to treat a total of 67 patients; from 2009 to 2010, the locking plate was used in 19 patients. Matching for gender, age, body mass index (BMI), and articular cartilage status, 19 pairs of wedge plate and locking plate cases were enrolled in a 1:1 retrospective matched-pair analysis. Clinical data were collected and scored using the visual analogue scale and the International Knee Documentation subjective score. Additionally, pre-operative, immediate post-operative, and last follow-up radiographs were obtained to assess changes in the hip-knee-ankle (H-K-A) angle and posterior tibial slope. No significant differences in gender, age, BMI, follow-up period, and articular cartilage status were found between the groups. Although the initial correction of the H-K-A angles, 8.9A degrees A A +/- A 1.9A degrees and 9.4A degrees A A +/- A 4.2A degrees for the wedge plate and locking plate groups, respectively, was not significantly different, a significant difference (P = 0.046) in the final correction angles, 7.2A degrees A A +/- A 2.1A degrees and 9.4A degrees A A +/- A 4.4A degrees, respectively, was found. The increase in the posterior tibial slope, 0.5A degrees A A +/- A 2.0A degrees and 3.2A degrees A A +/- A 2.6A degrees, for the wedge plate and locking plate groups, respectively, was significantly different (P = 0.010). When classified according to the correction angle, we found that when the initial correction angle exceeded 10.0A degrees, an average correction loss of 2.9A degrees A A +/- A 0.5A degrees was observed in the wedge plate group, whereas an average increase in the posterior tibial slope of 5.8A degrees A A +/- A 1.6A degrees was evident for the locking plate group. At 2 years post-operatively, the final correction angles of the wedge and the locking plate groups differed significantly, and the wedge plate group had a smaller increase in the posterior tibial slope than the locking plate group. Retrospective comparative study, Level III.