The anterior cruciate ligament (ACL) is a band of collagen connecting the femur to the tibia and one of the four ligaments crucial to stability within the knee joint. The ACL is one of the most commonly injured ligaments and is often stretched or torn with a sudden twisting motion. ACL injuries can occur with or without contact in sports. Women have a higher ACL injury incidence than their male counterparts. The reasons for this disparity range from hip and knee kinematics to hormonal differences.
If the ACL is only partially torn, surgery may not be necessary. An exercise program may be prescribed to strengthen surrounding muscles in combination with a brace to protect the knee during activity. If the ACL injury results in a complete tear, an ACL reconstruction surgery may be needed to restore joint stability.
In surgical treatment, a substitute graft replaces the torn ACL. Commonly used grafts include: patellar tendon autograft (autograft comes from the patient), hamstring tendon autograft, or an allograft (taken from a cadaver) tendon.
The selected tendon is harvested (for an autograft) or thawed (for an allograft) and the graft is prepared to be the correct size for the patient. After preparing the graft, the surgeon makes two small incisions called portals around the knee joint where the arthroscope and surgical instruments will be inserted. The arthroscope, a small camera, is then inserted into the knee and the surgeon examines the condition of the knee. The torn ACL is removed. A surgical drill is inserted and a tunnel is created for the ACL graft. The graft is pulled into position and is held under tension as it is fixed in place.
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