Abstract
The purpose of this study was to compare posterior tibial slope preoperatively and postoperatively in patients undergoing navigational opening-wedge High tibial osteotomy (HTO) and to compare posterior slope changes for 2 and 3-dimentional (D) navigation versions.
Between May 2009 and September 2010, 35 patients with unicompartmental osteoarthritis and varus deformity were treated by navigation-assisted open-wedge HTO. Patients were randomly divided into two groups according to the version of the Orthopilot (Aesculap) navigation system used; 2D group (18 patients, 2-D version) and 3D group (17 patients, 3-D version). Radiologic evaluations were conducted using pre- and postoperative leg axes. Posterior slope of proximal tibiae were measured using the proximal tibial anatomic axis method.
Postoperatively the mechanical axis was corrected adequately to a mean valgus of 2.81° in 2D group and of 3.15° in 3D group. Mean posterior slopes were well maintained, and measured 7.9° and 10.3° preoperatively and 8.99° and 9.14° postoperatively in 2D and 3D groups, respectively. No significant difference was found between the two navigation versions with respect to posterior tibial slope; mean tibial slope changes were 1.09° and −0.2° in 2D and 3D groups (p = 0.04).
Navigation-assisted opening-wedge HTO greatly improves the accuracy of the desired postoperative mechanical femorotibial axis and posterior tibial slope, and the use of 3D navigation results in significantly less change in posterior tibial slope. The authors recommend the use of the 3D navigation because they provide real time intraoperative information about coronal, sagittal, and transverse axis, which are important for the maintenance of a normal posterior tibial slope.
