Demographics and Injuries Associated With Knee Dislocation: A Prospective Review of 303 Patients.

BACKGROUND: Information on the incidence, injury mechanisms, ligament injury patterns, and associated injuries of knee dislocations is lacking in the literature. There is a need to characterize ligament injury patterns and associated injuries in knee dislocations to avoid missing common associated diagnoses and to plan surgical treatment.

PURPOSE: To evaluate patient demographics, ligament injury patterns and associated injury patterns, and associated injuries in patients with knee dislocation.

STUDY DESIGN: Cross-sectional study; Level of evidence, 3.

METHODS: A total of 303 patients with knee dislocations treated at a single level 1 trauma center were followed prospectively. Injury mechanism; ligament injury patterns; associated neurovascular, meniscal, and cartilage injuries; and surgical complications were recorded. The Schenck knee dislocation classification was used to classify the ligament injury patterns.

RESULTS: The mean age at injury was 37.8 ± 15.3 years. Of the 303 patients included, 65% were male and 35% were female. There was an equal distribution of high-energy and low-energy injuries. Injury to 3 major ligaments was the most common, with Schenck classification type KD III-M constituting 52.4% of the injuries and KD III-L comprising 28.1%. Meniscal injuries and cartilage injuries occurred in 37.3% and 28.3% of patients, respectively. Patients with acute injuries had significantly lower odds of a cartilage injury than those with chronic injuries (odds ratio [OR], 0.28; 95% CI, 0.15-0.50; P < .001). Peroneal nerve injuries were recorded in 19.2% of patients (10.9% partial and 8.3% complete deficit), while vascular injuries were recorded in 5%. The odds of having a common peroneal nerve injury were 42 times greater ( P < .001) among those with posterolateral corner injury (KD III-L) than those without. The odds for popliteal artery injury were 9 times greater ( P = .001) among those with KD III-L injuries than other ligament injury types.

CONCLUSION: Medial-sided bicruciate injuries were the most common injury pattern in knee dislocations. Cartilage injuries were common in chronically treated patients. There was a significant risk of peroneal nerve injury with lateral-sided injuries.