High Detection Rate of Posterolateral Tibial Plateau Fractures and Poor Functional Outcomes in Type IIIB Impaction Fractures After Anterior Cruciate Ligament Rupture and Reconstruction

Objective: The incidence of anterior cruciate ligament (ACL) ruptures has been increasing annually. However, clinical surgeons have overlooked the impaction fractures of the posterolateral tibial plateau and lateral femoral condyle in patients with ACL ruptures. The purpose of the present study was to report the detection rate of the posterolateral tibial plateau impaction fractures in patients with ACL ruptures, and to evaluate the functional outcomes of patients following ACL reconstruction (ACLR) without treatment of the tibial fractures at a 2-year postoperative follow-up. Methods: Four hundred eighty-eight patients treated for ACL ruptures between January 2016 and June 2020 were retrospectively reviewed, and the posterolateral tibial plateau impaction fractures were classified based on MRI assessment. The detection rate of the posterolateral tibial plateau impaction fractures was calculated, and the functional outcomes (SF-12 Mental Component Summaries, SF-12 Physical Component Summaries, Tegner, Lysholm, IKDC, and KOOS) were evaluated at a 2-year postoperative follow-up. Results: The detection rate of posterolateral tibial plateau impaction fractures was 41.6% among ACL ruptures. Of these, 285 cases (58.4%) had no fractures, 98 cases (20.1%) had type I impaction fractures, 41 cases (8.4%) had type IIA impaction fractures, 15 cases (3.1%) had type IIB impaction fractures, 22 cases (4.5%) had type IIIA impaction fractures, and 27 cases (5.5%) had type IIIB impaction fractures. Patients with type IIIA or IIIB impaction fractures showed an increased detection rate of contact mechanism compared to the other subgroups. Significant differences in Tegner (postoperation) and KOOS (QOL) were found between no fracture and type IIIB impaction fractures in patients following ACLR. Conclusions: The detection rate of posterolateral tibial plateau impaction fractures in patients with ACL ruptures was high. Patients with type IIIB impaction fractures following ACLR had poor functional outcomes.