Classification of Knee Dislocations

Abstract

The concept of a dislocated knee has changed over the past 20 years to include a wide variety of injury patterns. Although a dislocation is still defined as the complete displacement (even momentary) of the tibia and femur from their articulation, the presence and acceptance of spontaneously reduced dislocations and cruciate-intact (PCL or ACL) knee dislocations make the concept of a “dislocation” somewhat limited (Figure 3.1). Combining this change in the definition of a dislocation with the current understanding of functional anatomy of the knee gives the clinician wishing to find the proper treatment of a “knee dislocation” a much more accurate understanding of what is injured. The need for an accurate and reproducible classification system for knee dislocations is extremely important in the management of knee dislocations. The description of a knee dislocation based on the position of the tibia on the femur has limited clinical application. Position description says nothing about what is torn (i.e., cruciate intact vs complete bicruciate injuries) and cannot be applied at all to most traumatic dislocations that are spontaneously reduced. Thus classifying a knee dislocation by indicating what is torn is important and will be described in detail in this chapter.