Floating Knee Injury
DNB Orthopaedics • May 2024 • Paper II • 10 Marks
Introduction
A floating knee is a high-energy ipsilateral injury in which fractures of the femur and tibia effectively isolate the knee joint from the remainder of the limb. It is usually caused by road-traffic accidents, falls from height or other major-energy trauma and therefore should be regarded as a manifestation of polytrauma rather than merely two fractures occurring in the same limb.
These injuries are frequently associated with severe soft-tissue damage, open fractures, vascular injury, compartment syndrome, ligamentous knee injury and systemic complications. The prognosis depends not only on fracture union but also on the condition of the soft-tissue envelope, articular involvement and associated injuries.
Core concept: In a floating knee, treat the patient first, preserve the limb second, and reconstruct the fractures third.
A. Definition
Floating knee refers to ipsilateral fractures of the femur and tibia, with or without involvement of the knee articular surfaces, resulting in an unstable segment centred around the knee.
The classic form consists of an ipsilateral femoral shaft fracture and tibial shaft fracture. Modern usage also includes metaphyseal and intra-articular variants involving the distal femur or proximal tibia.