Patient-specific high tibial osteotomy for varus malalignment: 3D-printed plating technique and review of the literature.

Abstract

We report our experience with a 3D patient-specific instrument (PSI) in an opening-wedge tibial osteotomy for the correction of varus malalignment in a patient with prior anterior cruciate ligament reconstruction. Previous studies have not reported the use of 3D PSI in patients with prior knee surgeries. A pre-operative CT was used to create a 3D model of the lower extremity using Bodycad Imager. The pre-operative medial proximal tibial angle (MPTA), lateral distal femoral ankle, hip-knee-ankle (HKA), and tibial slope were calculated. The Bodycad Osteotomy software package was used to create a simulated osteotomy and correction. The resulting 3D patient-specific surgical guide and plate were used to conduct the high tibial osteotomy. Radiographic measurements and range of motion were evaluated at 6-week follow-up. The arthroscopy and open portions of the procedure were performed in 65 min, with only three fluoroscopy shots taken intraoperatively. At 6-week follow-up, the patient had 125° of flexion and minimal pain. The angular correction of the bone was achieved within 1.9° (planned MPTA 91.9° vs. actual 90°); the HKA angle was achieved with an error of 0.7° (planned 2.4° vs. actual 1.7°); and there was no change in the posterior tibial slope (planned 13.5° vs 13.8° actual). Three-dimensional PSI can be successfully used for the accurate and efficient correction of varus malalignment while accommodating pre-existing hardware, with good short-term clinical outcomes.