Knee joint dislocations-Current epidemiology and treatment in Germany.

Purpose: Knee joint dislocations, though rare, present significant challenges due to potential complications like vascular and nerve damage, and are known to be often linked to sports injuries, accidents and obesity. This study aims to analyse the epidemiology, incidence and treatment approaches for knee dislocations in Germany from 2019 to 2022.

Methods: This retrospective cohort study utilized data from the German Institute for the Hospital Remuneration System to examine knee dislocation cases across German medical institutions. Patient data coded under International Statistical Classification of Diseases and Related Health Problems 10 for 'knee dislocation' enabled detailed analysis by age, sex and surgical procedures categorized by operation and procedure codes. The Patient Clinical Complexity Level (PCCL) assessed complication severity.

Results: Analysis of 1643 knee dislocation cases revealed an incidence rate of 0.44-0.54 per 100,000 inhabitants annually. During the years 2020 and 2021, there were fewer cases of knee dislocations. Male patients comprised 50%-56% of cases, with an average hospital stay of 11 days. Most cases were PCCL 0 (62%-72%) and predominantly affected patients aged 18-29 years. Anterior tibial dislocations were common among classified cases. Injuries included ligament ruptures, meniscus lesions and grade I soft-tissue injuries. Patients with pre-existing knee prostheses constituted 0%-16% annually. Treatment involved closed reduction, external fixation and surgeries like capsuloligamentous reconstructions and arthroscopic procedures. Revision knee arthroplasty was required in 2%-9% of cases, with obesity rates up to 7%.

Conclusions: This study provides valuable insights into the epidemiology, incidence and treatment of knee dislocations in Germany, with a focus on demographic risk factors, treatment complexities and the impact of obesity and knee prostheses. The findings emphasize the importance of specialized care in larger hospitals, comprehensive management of concomitant injuries and the need for improved coding accuracy. Future research should aim to refine treatment protocols.

Level of evidence: Level III.