Fixation method can affect posterior tibial slope in opening-wedge high tibial osteotomy: a retrospective study

Background Posterior tibial slope (PTS) alterations following open-wedge high tibial osteotomy (OWHTO) can cause instability and excessive tibial translation in the sagittal plane. These changes can be influenced by the type of fixation. This study aims to compare PTS changes between patients undergoing OWHTO with Puddu plate or TomoFix plate fixation. Methods In this retrospective cohort study, we included 104 knees from 85 patients undergoing OWHTO, with a mean age of 41.98 [+ or -] 9.95 years; 51.8% of the participants were male. Seventy-two knees were fixed with Puddu plates, while 32 knees were fixed with TomoFix plates. PTS changes, demographic factors, Cincinnati Knee Rating Score (CKRS), Tegner-Lysholm score (TLS), length of stay (LOS), and complications were evaluated. PTS changes were measured preoperatively, immediately postoperatively, and at the 6-month follow-up. Results Demographic factors were similar between the Puddu plate and TomoFix groups. There were no significant differences in preoperative, postoperative, or follow-up PTS measurements between the two groups. PTS changes were not significant in the TomoFix group postoperatively or at follow-up. However, the Puddu plate group showed a significant increase in PTS both postoperatively (P = 0.027) and at follow-up (P = 0.014). CKRS, TLS, LOS, and complications did not significantly differ between the groups. Conclusion While overall PTS changes did not significantly differ between the Puddu Plate and TomoFix Plate groups, analyzing changes within each group revealed distinct results. TomoFix fixation exhibited nonsignificant PTS changes, while Puddu plate fixation resulted in a significant increase in PTS after surgery and at the 6-month follow-up. Our findings suggest that the choice of fixation may influence PTS changes after OWHTO. Level of Evidence: Level III. Keywords: High tibial osteotomy, TomoFix, Puddu, Posterior tibial slope