ABSTRACT
This study examined whether medial opening wedge osteotomy inadvertently changes posterior
tibial slope and whether this change affects range of motion and functional outcomes.
Lateral radiographs of 82 knees with varus arthrosis were reviewed to measure posterior
tibial slope before and after medial opening wedge high tibial osteotomy. Anterior
or posterior cruciate ligament-deficient knees were excluded. Twenty-one osteotomies
were performed using distraction osteogenesis/medial external fixator, 26 using acute
distraction/Arthrex plate fixation, and 35 using acute distraction/EBI plate fixation.
Preoperative and postoperative Lysholm scores and range of motion were recorded. Posterior
slope increased from a mean of 12.5° preoperatively to 16.5° postoperatively (P < .01). Fixation types revealed no difference in posterior slope change. Large slope
changes had less preoperative knee flexion than did small changes (123 versus 131;
P = .012). No significant correlation existed between posterior slope change and postoperative
Lysholm scores (r = 0.047, P > .05). We found that medial opening wedge osteotomy may alter sagittal alignment
by increasing posterior tibial slope.