Rethinking the Schenck Classification for Multiligament Knee Injuries: Evaluating Whether the Schenck KD Grade Is Associated With the Presence of Vascular or Neurological Injuries in a Multicenter Study With 144 Patients.

Abstract

Background: Posterolateral corner (PLC) lesions and knee dislocations (KDs) have been recognized as risk factors for vascular and neurological injuries in patients with multiligament knee injury (MLKI), but an association between Schenck KD grade and neurovascular lesions has yet to be established.

Hypothesis: The ligamentous injury pattern in MLKIs with high KD grades will be associated with a higher likelihood of vascular and neurological injuries.

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

Methods: Included were 144 patients from a multicenter database with surgically treated MLKI. All patients were skeletally mature, had MLKI lesion identified on magnetic resonance imaging and confirmed intraoperatively, and did not have any previous knee surgery or previous vascular or neurological lesions. Demographic data (sex, age), injury mechanism (high energy, sports injury, low energy), ligaments injured, and neurological and vascular lesions were recorded. A new classification for MLKI based on ligamentous injury pattern, and intended for all MLKIs (with and without KD) was developed, and all patients were categorized according to this classification. Associations were evaluated between the risk of vascular and neurological lesion and demographic data, injury mechanism, and new classification grade.

Results: The mean patient age was 33.9 years (range, 15-64 years), and 72% were male. High-energy trauma was the most common injury mechanism (55.6%). Vascular injury was present in 5 patients (3.5%) and nerve injury in 17 (11.8%), with 1 patient (0.7%) having both. None of the analyzed variables were associated with the presence of vascular lesion. Univariate logistic regression showed that medial collateral ligament (MCL) lesion decreased the probability of neurological injury (odds ratio [OR], 0.29; 95% CI, 0.1-0.87; P = .03) while PLC injury increased that probability (OR, 12.66; 95% CI, 1.63-100; P = .02). Multivariate logistic regression showed that the proposed MLKI grade was significantly associated with the presence of neurological lesions, with a 2.5-fold increase in the odds of having a neurological injury for each increase in grade (OR, 2.47; 95% CI, 1.36-4.50; P = .003).

Conclusion: PLC injuries increased the odds of neurological injury in MLKI, while MCL injuries decreased these odds. MLKI grade and presence of PLC injury was associated with the presence of neurological injury. MLKI grade was not associated with the presence of a vascular lesion.