Challenges and outcomes in the treatment of floating knees. A case series of ipsilateral femur and tibia fractures around the knee.

Background Ipsilateral femur and tibia fractures around the knee (floating knee) are rare injuries that threaten both limb viability and patient life. A correct surgical strategy is essential to reduce complications and sequelae. The aim of this study was to evaluate characteristics and results of treatment in patients with a floating knee treated at a single trauma center. Material and methods This is a retrospective and non-consecutive case series of 18 floating knees occurred in 17 patients. All patients were operated in a single third-level public and university hospital from December 2010 to December 2018. Data on demographics, injuries, treatment and follow-up were collected. A general health questionnaire (SF-12) and a knee functional questionnaire (KOOS-PS) were used to display results. Results We identified 13 men and 4 women, aged between 16 and 52. Mean follow-up period was 16.49 months. High-energy trauma following a traffic collision was the most frequent mechanism. Mean Injury Severity Score (ISS) was 39.05, and a damage control strategy was used in 15 (83.33%) injuries. Extra-articular fractures (Fraser I) largely predominated, resulting in double intramedullary nailing in 72.22% of cases. Eleven injuries (61.11%) presented with an open fracture. Complications appeared in 6 (33.33%) injuries, being 3 infections. Mean score for the SF-12 was 35.59 for the physical dimension and 50.44 for mental dimension. Mean score for the KOOS-PS was 43.64. Conclusion Floating knee injuries usually occur in polytrauma contexts. Visceral involvement and exposed fractures are common, so the most appropriate strategy is usually a staged treatment. Complications and sequelae are frequent.