Purpose
Changes of posterior tibial slope following complex tibial plateau fractures have not been fully evaluated in the literature. Some studies indicated that arthritic changes that occur following tibial plateau fracture were more correlated to deformity and instability rather than articular surface step-off.
Patients and methods
This retrospective cohort study was carried out on 112 patients operated by internal fixation following complex tibial plateau fracture within 4 weeks of the incident of injury. Modified Rasmussen score was used for both clinical and radiological evaluations in addition to final evaluation of the slope by computed tomography scan. The Knee Injury and Osteoarthritis Outcome Score was used for subjective evaluation of the clinical results, and Kellgren–Lawrence radiological grading was used for osteoarthritis grading.
Results
The mean flexion was 118.8 ± 13.0° (range, 90–140) in GI and 119.7 ± 13.5° (range, 70–140) in GII, and the mean extension deficit was 1.6 ± 2.7° (range, 0–10) in GI compared with 1.9 ± 2.9° (range, 0–10) in GII. The mean clinical Rasmussen score was 26.3 ± 2.9 (18–30) in GI and 26.1 ± 3.2 (16–30) in GII. The mean Knee Injury and Osteoarthritis Outcome Score in GI was 79.3 ± 5.1 compared with 77.7 ± 5.6 in GII. According to Kellgren–Lawrence grading system for osteoarthritis, there were 23 patients with grades 2 and 3 osteoarthritis in GI compared with 32 cases in GII. The study showed a statistically significant correlation between decreased tibial slope and limitation of extension. Otherwise, there were no statistically significances between changes of tibial slope and stability, pain, or the overall postoperative knee score.
Conclusion
Changes in posterior slope angle of the tibial plateau during fracture fixation is an important factor that can significantly affect range of motion, particularly extension. Osteoarthritis is higher in patients with disturbed posterior slope; however, a larger sample is needed for possible significance.