Measurement and evaluation of dynamic joint stability of the knee and ankle after injury.

Injuries to the lower extremity, specifically the knee and ankle joints of the human body can occur in any athletic event and are most prevalent in sports requiring cutting and jumping manoeuvres. These joints are forced to rely on the dynamic restraints to maintain joint stability, due to the lack of bony congruence and the inability of the static restraints to handle the forces generated during functional tasks. Numerous variables (proprioception, postural control, electromyography, kinetics/kinematics, dynamic stability protocols) have been measured to better understand how the body maintains joint stability during a wide range of activities from static standing to dynamic cutting or landing from a jump. While the importance of dynamic restraints is not questioned, a recent impetus to conduct more functional or sport-specific testing has emerged and placed a great deal of emphasis on dynamic joint stability and how it is affected by lower extremity injuries. Evidence suggests that surgery and aggressive rehabilitation will not necessarily restore the deficits in dynamic joint stability caused by injury to the anterior cruciate ligament or lateral ankle ligaments. In today's athletic society, there is a major push to return athletes to play as quickly as possible. However, the ramifications of those decisions have not been fully grasped. If an athlete is not fully recovered, a quick return to play could start a vicious cycle of chronic injuries or permanent disability.