Poly-traumatic multi-ligament knee injuries: is the knee the limiting factor?

Purpose Multi-ligament knee injuries (MLKI) from a high-velocity accident are rare but potentially devastating. This matched cohort analysis compares knee functional outcomes after multiple ligament reconstruction in poly-trauma patients to those that occurred in isolation. Methods Sixty-two patients with MLKI that occurred either as a component of polytrauma or had occurred in isolation were matched according to age, sex, and knee dislocation grade. Functional outcomes and knee physical examination were assessed at a 2-year follow-up. New Injury Severity Score (NISS) was calculated based on the poly-traumatic injury pattern. Risk factors for worse outcomes in the poly-trauma cohort were analyzed. Results The mean IKDC, Lysholm, and NISS scores in the polytrauma cohort were 57.2 +/- 21.9, 62 +/- 22, and 40.9 +/- 20.4, respectively, at a mean of 67 months (range 24-220). The isolated knee injury group was followed for a mean of 74 months (range 24-266) with mean IKDC and Lysholm scores of 71.1 +/- 26.5 and 78 +/- 23, respectively. Patients in the control cohort had significantly higher IKDC (p = 0.01) and Lysholm scores, (p = 0.003). There were no major differences between the two groups in regards physical examination findings at final follow-up. None of the analyzed risk factors was predictive of poor outcome. Conclusion When comparing knees with similar multi-ligament and neurovascular injury patterns, patients who sustained their injury as a result of poly-trauma demonstrated significantly lower functional scores following reconstruction. This is despite restoration of similar knee stability and range of motion. The functional outcomes following MLKI reconstruction in poly-traumatized patients are influenced by factors other than the knee including concomitant injuries and psychosocial factors.