Personalised High Tibial Osteotomy Surgery is Accurate: An Assessment Using 3D Distance Mapping

Early-stage knee osteoarthritis is often suitable for treatment with high-tibial-osteotomy (HTO). This is an effective joint preserving treatment, resulting in good postoperative outcomes. To overcome the limitations of traditional HTO, the surgical technique and correction accuracy can be enhanced by personalised procedures using three-dimensional digital planning and metal additive-manufacturing, The purpose of this clinical trial study was to evaluate the three-dimensional accuracy of a new personalized HTO procedure, using modern imaging techniques, 3D-modelling and distance-map-analysis (DMA). Twenty-five patients were treated with the per-sonalized HTO procedure. Before surgery and after 6 months, they underwent clinical evaluation scoring, radiographic imaging and computed-tomography scanning to generate morphological models. Specifically, preoperative tibia models were used to plan the tibia correction and the de-sign and position of the fixation-plate. Preoperative, planned and postoperative models were imported in computer-aided-designing software for DMA implementation to assess geometrical differences between model surfaces. A very good reproduction of the planned tibia morphology was achieved postoperatively (average differences between -0.9 mm and 1.4 mm). DMA values associated with fixation-plate deformation were less than 1 mm, similar to those for plate-to-tibia surface-contour matching. Overall, personalised digitally-planned HTO utilising three-dimensional printed surgical guides and plates enables accurate planned correction and plate placement.