Challenge #3:
A basketball player tears her ACL during a game. She wishes to continue playing without reconstructive surgery. How will she adapt her movements to a torn ACL? Test the 3-D kinematics using a 6-DOF goniometer

What is the ACL?
The anterior cruciate ligament (ACL) is one of the ligaments in the knee. It extends from the posterior part of the medial surface of the lateral femoral condyle to the anterior surface of the tibial plateau.(Clemente) It helps to maintain the overall stability of the knee by limiting its rotational and translational motion. Specifically, the anterior cruciate ligament helps prevent the posterior, or backward, displacement of the femur on the upper tibial plateau.(Clemente)

Flexed Right Knee Joint(Anterior View) Showing the Cruciate Ligament

What is an ACL injury?
The ACL can be partially torn or completely torn, resulting in loss of overall stability. Injuries are most often associated with sports like skiing, basketball, and football. For non-contact ACL injuries, sudden deceleration, abrupt change in direction, fixed foot and tibial rotation have been reported as key elements of ACL injuries. The common mechanisms of ACL injury include a subject falling backward with the quadriceps flexed and the foot planted, a shifting of the tibia forward, and external rotation when the leg is abducted.(Kirkedall et al.)

There are many proposed causes of ACL injury. One of the theories is that the balance of muscle power between the quadriceps and the hamstrings may contribute to ACL injury. The quadriceps are ACL antagonists and the stronger they are, without a corresponding increase in hamstring strength(ACL agonists), the more likely an individual will be predisposed to ACL injury. (Boden)

For more information check out the Sports Medicine Institute

You are given the Goniometer Video and Data of both a healthy patient and one with a torn ACL. Perform an analysis.

Goniometer Description
Procedure
Analysis & Questions
Sample Analysis

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