Epidemiology of Polytraumatic Versus Isolated Multi-Ligament Knee Injuries Over an 11-Year Period at a Level One Trauma Centre: A Retrospective Observational Study

Poly-traumatic multi-ligament knee injuries (PT-MLKI) represents a severe and complex subset of knee injuries, often resulting from high-energy trauma. This study compares the epidemiology, injury patterns, management strategies, and complications PT-MLKI and isolated knee injuries over an 11 year period at a level-1 trauma centre. A retrospective observational study was conducted from August 2013 to May 2024, including 101 patients (105 knees) with either PT-MLKI (40 knees) or isolated knee injuries (65 knees). Data was collected from electronic patient records, radiology reports, and multidisciplinary team documentation. The mean age of patients in both groups was comparable (PT-MLKI: 36 years; isolated injuries: 35 years) with a male predominance (72.2% in PT-MLKI vs. 64.6% in isolated injuries) primarily within the 25–45 year age range. PT-MLKI were more commonly associated with motorcycle vs. car (44.4%) and pedestrian vs. car (30.6%) accidents, whereas isolated injuries often resulted from falls from heights less than 1m (36.9%), falls from heights greater than 1m (20%), and sports-related incidents(16.8%), with the distribution of injury mechanisms being statistically significant (p < 0 .05). Knee dislocations were significantly more prevalent in isolated injuries (63% vs. 40%, p=0.04) with the isolated injury group also exhibiting a higher mean BMI (34 vs 28.1). The most frequent dislocation type in PT-MLKI group was a KD III (43.8%), followed by KD II (37.5%), and KD IV (18.8%). In isolated injuries, KD III was also the most common (61%), followed by KD II (34.1%), and KD IV (4.9%). Vascular injuries involving the popliteal artery occurred in 20% of PT-MLKI cases compared to 9.2% in isolated injuries (p=0.2). Common peroneal nerve (CPN) injuries were present in 32.5% of PT-MLKI cases versus 16.9% in isolated injuries (p=0.11). Surgical management was implemented in 70% of PT-MLKI cases versus 72.3% of isolated injuries (p=0.006), with a mean time to ligament reconstruction of 6.2 weeks (range 2–20 weeks) in PT-MLKI compared to 15.8 weeks in isolated injuries. Postoperative complications were observed in 15% of PT-MLKI cases versus 7.7% in isolated injuries. PT-MLKI are predominantly associated with high-energy trauma and exhibit higher rates of vascular and CPN injuries, quicker time to surgical intervention and a higher incidence of postoperative complications compared to isolated knee injuries. These findings underscore the need for heightened vigilance and tailored management strategies in patients with PT-MLKI.