The known and unknown reality of knee dislocations: A systematic review.

Background: Knee dislocations (KD) are limb threatening injuries known to cause significant dysfunction and disability. This review aims to summarize KD knowledge and uncover areas where more research is needed.

Methods: The published literature was queried according to PRISMA guidelines. Studies eligible for inclusion were clinical studies of knee dislocations. Studies published before 1990, or that focused on patellofemoral dislocation were excluded.

Results: A total of 132 studies involving 43,869 knee dislocations were analyzed. The majority of patients were young adult males, with high-velocity trauma, particularly motor vehicle accidents, being the most common cause. Substance use and alcohol involvement were commonly reported. The predominant KD types were KD III (54.8 %) and KD IV (20.5 %). Meniscal tears were observed in over 50 % of cases, while cartilage injuries were present in 26.7 %. Neurovascular complications were significant, with popliteal artery injuries in 7.8 % and peroneal nerve injuries in 15.3 % of patients. Acute ligament repairs (64.2 %) were more common than delayed repairs (35.8 %), although the average time to repair was 56.1 days. Complications included amputations (2.3 %), fatalities (1.9 %), compartment syndrome (2.7 %), deep infection (5.3 %), and heterotopic ossification (21.6 %). Despite these severe injuries, a substantial loss to follow-up (19 %) and underreporting of functional outcomes were noted, limiting the comprehensive assessment of long-term recovery. A notable percentage of patients did not return to work or sports, with many requiring a change in profession due to their injuries, but these outcomes were only reported in 10 or fewer studies.

Conclusion: This study highlights the significant gaps in understanding the treatment strategies, financial burden, and long-term outcomes of knee dislocations. The incomplete data, particularly the high loss to follow-up rates and underreported functional outcomes, hinders the ability to make comprehensive assessments. Available results should thusly be interpreted with an understanding of the gaps in data, however return to sport and prior employment is often not achieved. Additionally, the potential influence of socioeconomic factors and substance abuse on treatment decisions and outcomes remains inadequately explored. Future research should focus on these areas to improve the management and prognosis of patients with knee dislocations, ensuring more accurate and thorough evaluations of long-term recovery and quality of life.