The Pediatric "floating Knee" Injury: A State-of-the-Art Multicenter Study

Background:Isolated femoral and tibial fractures are 2 of the top 5 causes of pediatric orthopaedic hospital admission, yet their simultaneous ipsilateral presentation, the "floating knee" injury, remains rare. Historically, treatment consisted of traction and cast immobilization, which resulted in prolonged periods of immobilization, lengthy hospitalizations, and high rates of malunion. As such, previous authors have recommended fixation of at least 1 bone in the setting of a floating knee injury. This strategy, however, has never been evaluated and the outcomes of modern treatment are unknown.Methods:We performed a multicenter retrospective review of the records of pediatric patients with ipsilateral femoral and tibial fractures that had been treated at 11 tertiary care level-I pediatric trauma centers from 2004 to 2014. Outcomes and treatment strategies were assessed with standardized means.Results:Over the study period, 130 floating knees in 129 patients met the inclusion criteria for evaluation. The average patient age was 10.2 years, and 63.1% were male. One-third of the patients presented with open injuries, and 83.8% of injuries were related to vehicular trauma. Simple diaphyseal fractures (OTA/AO 32-A and B femoral fractures and OTA/AO 42-A and B tibial fractures) were most common. Intramedullary fixation (rigid or flexible) was the most common treatment strategy for femoral fractures (69.2%). Tibial fractures were treated most commonly with casting (27.7%), followed by flexible intramedullary nailing (24.6%). The mean duration of hospitalization was 9.7 days. Outcomes were excellent in 66.6% of cases and good in 26.4% of cases.Conclusions:Previous literature on pediatric floating knee injuries consisted of small case series that were published prior to the introduction of flexible intramedullary nailing to North America. This multicenter study of a large cohort demonstrates a change in practice pattern from a largely nonoperative treatment strategy to operative fixation of at least the femoral fracture. In the present study, this approach led to good or excellent results in 93.1% of cases and was associated with a short duration of hospitalization.Level of Evidence:Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.