Abstract
Purpose
Surgical treatment of tibial plateau fractures involves anatomic reduction and rigid fixation. A residual articular depression may alter the joint contact pressure and lower limb alignment and precipitate posttraumatic osteoarthritis. The degree of acceptable articular incongruency remains controversial, and the correlation between malreduction and malalignment has not been thoroughly investigated. We investigated the correlation between postoperative articular congruency in different fracture zones in the sagittal plane and whole lower limb alignment after surgery for lateral tibial plateau fractures.
Materials and Methods
Among the 254 patients surgically treated for plateau tibia fractures between January 2010 and December 2022 at a single center, 67 patients of all ages with lateral tibial plateau fractures (Schatzker types I–III) were selected and retrospectively reviewed. All patients underwent open reduction and internal fixation (ORIF) via plate and screw construct, with or without an augmentation procedure. We used simple radiographs and preoperative three-dimensional computed tomography to measure lower extremity alignment variables, intra-articular step-offs, and fracture zones in the sagittal plane. We stratified the fracture site into three zones in the sagittal plane at the joint center of the lateral tibial plateau. Malreduction was defined as an articular step-off ≥ 2 mm. Malalignment was defined as a difference > 5° in hip-knee-ankle angle (HKA).
Results
HKA strongly correlated with postoperative articular step-off (Spearman's ρ = -0.69; p < 0.001). Postoperative valgization of HKA was significantly associated with increased articular incongruency (β= -0.96, p < 0.001), particularly with step-offs ≥ 2 mm (β= -3.77, p < 0.001). Linear regression of articular step-offs and fracture locations did not demonstrate any significance. However, 13 of 24 malreduced fractures (54%) were in zone 2. Only zone 2 significantly affected postoperative valgization when assessing the association between fracture location and HKA (β = -2.68, p < 0.001). Articular incongruency located in zone 2 showed a significant association with HKA valgization after controlling for fractures in zones 1 and 3 (β = -0.775, p < 0.001).
Conclusion
This study highlighted that the articular step-off should be minimized to < 2 mm during surgery for lateral tibial plateau fractures to prevent valgus malalignment of the whole lower limb.