Tibial slope after Medial Opening-Wedge High Tibial Osteotomy: Is plate positioning the biggest issue?

Objetive: One major cause of Medial Opening-Wedge High Tibial Osteotomy (MOW-HTO) failure is inadvertent Posterior Tibial Slope (PTS) increase. To avoid this complication, posterior placement of the wedge plate is traditionally recommended. However, in the attempt of achieving such positioning, surgeon may encounter some undesired consequences, like medial collateral ligament disruption, instability or neurovascular injury. The purpose of this study is to evaluate the correlation between plate position in the sagittal plane and posterior tibial slope, in patients undergoing MOW-HTO. Methods: Forty-three patients undergoing MOW-HTO were radiographically evaluated, before and after surgery, to determine posterior tibial slope changes and plate position. to 10.3 ± 4.9 degrees (p = 0.0005)-this was not influenced by position or size of the plate. High values of posterior slope before surgery were correlated with greater increases after surgery. Conclusion: Plate positioning and wedge size were not related to PTS change, but patients with high preoperative PTS values showed a significantly greater increase in postoperative PTS. Level of evidence: Level 4 – case series.