No influence of posterior tibial slope change on outcomes after cruciate-retaining total knee arthroplasty: a prospective cohort study

Abstract

Objective To investigate whether the functional outcomes were affected by the change in posterior tibial slope (PTS) after using a predetermined PTS for primary cruciate-retaining total knee arthroplasty (CR-TKA). Methods Prospective cohort study of 152 patients who underwent primary CR-TKA with a standardized PTS of 5º regardless of the native PTS. Patients were classified postoperatively in two ways. Firstly, according to the PTS change from preoperative to postoperative (increased or decreased PTS group). Secondly, according to the PTS difference between preoperative and postoperative ≤ 4º (group A) and > 4º (group B). The functional outcomes were assessed with the Knee Society Scores (KSS), McMaster Universities Osteoarthritis Index questionnaire (WOMAC), and range of motion (ROM). Preoperative and postoperative PTS were measured on lateral knee radiographs. Results The minimum follow-up was 5 year. There were no significant differences at the final follow-up in functional outcomes between increased (88 patients) and decreased (64 patients) PTS groups. Likewise, there were no significant differences in functional outcomes between group A (79 patients) and group B (73 patients). In multivariate analysis, the PTS change was not significant predictor for improvement in functional outcome (OR 1.08; 95% CI 0.70–1.40; p = 0.061). Conclusion The PTS change between preoperative and postoperative has no influence on the functional outcomes using a CR-TKA. A standardized PTS regardless of the native is a reliable procedure for primary CR-TKA.

Accurate surgical posterior tibial slope alteration can be achieved in total knee arthroplasty regardless of surgeon skill level or local soft tissue thickness—A retrospective radiograph‐based study

“…The lack of assessment of both patient‐reported and objective knee function parameters in this study precludes conclusions on the impact of surgical PTS changes on postoperative outcome in TKA. First works on this impact reported it to be non‐existent to low [21, 24]. While further investigations are still needed to elucidate on the correlation of surgical PTS alteration and patient outcome, this study proved that biomechanical considerations of PTS alteration as a tool of sagittal balancing in TKA can be put into practice.…”