Helical instability of the knee: a concept and surgical reconstruction.

Tis presentation is based on the concept that stability of the functioning knee is dependent upon the tracing integrity of the tibia in relationship to the femoral condyles. The femur is considered to be the anchored, inherently fixed, and stable component of the knee joint and the tibia, the mobile unit which must be maintained in constant equilibrium with the femur. This stable equilibrium must be maintained in an infinite