We sought to determine the usefulness and the disadvantages of the navigation in medial opening wedge high tibial osteotomy (MOWHTO) compared to the conventional technique, in terms of target coronal alignment achievement, tibial slope maintenance, radiation exposure and operative time.
We retrospectively compared 40 knees treated with navigated MOWHTO by one surgeon with 20 knees treated with conventional MOWHTO by another surgeon. Screw length of the plate was predetermined using validated simple algorithms only in the navigation group to facilitate the operation. The acceptable range of the postoperative coronal alignment was defined as 2°-6° of the mechanical tibiofemoral angle (mTFA) and 55%-70% of the weight loading line coordinate (WLL). The proportion of the coronal alignment outlier, posterior tibial slope change, fluoroscopy time and operative time were compared.
The coronal alignment outliers were fewer in the navigation group, but the differences were not significant (mTFA outlier 18% vs. 30%, p = 0.326; WLL outlier 20% vs. 30%, p = 0.519). Tibial slope was maintained in the navigation group (+0.3°, p = 0.732), whereas increased in the conventional group (+3°, p < 0.001). The fluoroscopy time was shorter in the navigation group (10.4 seconds vs. 24.8 seconds, p < 0.001). The operative time was comparable in both groups (41.3 minutes vs. 39.2 minutes, p = 0.232).
Level III, retrospective comparative study.
The use of navigation can improve tibial slope maintenance and reduce radiation exposure in MOWHTO, without considerable extension of operative time by optimising the surgical technique.