Using 3D-printed models for pre-planning of high tibial osteotomy

Abstract

Background: This study aimed to assess the use of 3D-printed models for preoperative planning of high tibial osteotomy (HTO) in patients with genu varum deformity. Method: This study included Sixteen patients with genu varum divided into two groups: the model group and the control group. Before and after the operation, all patients in both groups underwent a lower limb standing alignment radiograph to measure mMPTA (mechanical Medial Proximal Tibial Angle), mLDFA (mechanical Lateral Distal Femur Angle), CA (Convergence Angle), and mFTA (mechanical FemuroTibial Angle). For the model group, a 3D-printed model was prepared before the surgery, and open wedge HTO was performed using this model. PTS (posterior tibial slope) and TTA (tibial torsion angle) were also measured in the model group, before and after operation. The control group underwent surgery without using a 3D printed model. Following the operation, the angles and the size of the bone opening in the medial axis on the model that underwent surgery were examined, and the measurements were recorded. Results: There was no significant difference between the groups regarding age, sex, body mass index (BMI), and side of injury. This study found no significant differences in mMPTA, mLDFA, mFTA, and CA between the groups in the 2D image. However, all angles changed significantly in both groups postoperatively, except for mLDFA in the model group. The mean changes in mMPTA, mFTA, and mMLDFA did not significantly differ between the groups, except for CA (P = .012). In the 3D model, PTS increased significantly while TTA decreased. Comparing angles between the 2D image and 3D model showed statistically significant differences, except for mFTA. The size of bone opening along the medial axis did not differ significantly between real surgery and the 3D model. The cost of hospitalization, cost of anesthesia, operation time, and also number of fluoroscopies were significantly lower in the model group compared to the control group. Conclusion: Using a 3D model for preoperative planning improved the correction of genu varum deformity in HTO. It also reduced the operation time, hospitalization and anesthesia costs, and fluoroscopy usage.