The effect of medial open wedge high tibial osteotomy and lateral closed wedge high tibial osteotomy on posterior tibial slope

Osteoarthritis (OA) is a disease that occurs when the relationship between articular cartilage and subchondral bone destruction and construction is disturbed. The most common causes of unicompartmental osteoarthritis are generally mechanical axis problems. In varus knees, medial compartment arthrosis is usually seen and the drawn mechanical axis passes through the medial part of the joint. To solve this problem, high tibial osteotomy (HTO) technique has been introduced to reduce the load on the medial compartment and equalise the load distribution. The aim of our study was to investigate the change of posterior tibial slope in patients who underwent medial open wedge high tibial osteotomy and lateral closed wedge high tibial osteotomy. The study was carried out on 63 patients who applied to Gaziantep University Faculty of Medicine, Department of Orthopaedics and Traumatology between 2018 and 2023 with knee pain, had varus deformity in the medial compartment on direct radiographs, and underwent medial open wedge high tibial osteotomy and lateral closed wedge high tibial osteotomy. Posterior tibial inclination angles of each group were measured on lateral radiographs. As a result of the measurements, the groups were statistically compared between each other. Pre-op PTEA value was 8.08 ± 3.93 and post-op PTEA value was 9.26 ± 4.03 in the patient group who underwent medial open wedge osteotomy (MOWO). Accordingly, there was no significant difference between pre-op and post-op PTEA in the MAKO group (p>0.05). Pre-op PTEA value was 7.75 ± 3.43 and post-op PTEA value was 6.71 ± 3.55 in the lateral closed wedge osteotomy (LCWO) group (p>0.05). The mean postoperative posterior tibial slope of the MAKO group was 9.26 ± 4.03, while the mean postoperative PTEA of the LKKO group was 6.71 ± 3.55. A statistically significant difference was observed (p<0.05). It was concluded that the posterior tibial slope increased after medial open wedge high tibial osteotomy and it was concluded that this result was compatible with the literature. After lateral closed wedge high tibial osteotomy, it was shown in our study that there was a difference in the preoperative posterior tibial slope and postoperative tibial slope and the slope decreased in closed wedge high tibial osteotomy and this result was supported by the literature.