The Incidence of Posterolateral Tibial Plateau Fractures in the Setting of Knee Dislocations.

Abstract

Background: Acute knee dislocations are devastating injuries that can be challenging for surgeons to treat. The bony integrity of the tibial plateau and the lateral femoral condyle has a fundamental meaning for translational and rotational knee joint stability. Posterolateral tibial plateau depression fractures (PLTPFs) and lateral femoral condyle impaction fractures (LFCIFs) can influence clinical outcomes, but their frequency and characteristics in the setting of acute knee dislocations are unknown.

Purpose: To report the incidence of PLTPFs and LFCIFs in acute knee dislocations as well as to describe concomitant soft tissue lesions associated with these bony injuries.

Study design: Cross-sectional study; Level of evidence, 3.

Methods: In this retrospective multicenter study, acute knee dislocations (at least bicruciate ligament injuries) were identified from hospital information systems based on diagnosis-related group coding as well as operation and procedure classification coding at 5 participating level 1 trauma centers from 2018 to 2022. The knee dislocations were categorized according to the Schenck classification. Soft tissue injuries were assessed on magnetic resonance imaging within 2 weeks of the trauma. PLTPFs and LFCIFs were categorized on magnetic resonance imaging and computed tomography according to the Menzdorf and Bernholt classifications.

Results: A total of 157 knee dislocations were identified, comprising 106 men and 51 women with a mean age of 39.3 ± 15.1 years. A PLTPF was detected in 42 (26.8%) knee dislocations, with the highest frequency in Schenck type III medial dislocations. Of these 42 cases, 26 (61.9%) PLTPFs were rated as high-grade fractures, theoretically requiring reduction and fixation. An LFCIF was found in 31 (19.7%) of the cases.

Conclusion: A PLTPF was observed in one-quarter, and an LFCIF in one-fifth, of acute knee dislocations. They occurred particularly in knee dislocations with medial collateral ligament ruptures. Almost two-thirds of all PLTPFs presented as high-grade fractures according to the Menzdorf or Bernholt classification, potentially requiring a surgical intervention.