The knee has 4 primary stabilizing ligaments. The medial collateral ligament (on the inside) provides side to side stability. The lateral collateral ligament (on the outside) provides side to side stability. The anterior cruciate ligament in the center of the knee provides stability by not allowing the tibia to slide forward on the femur. The posterior cruciate ligament provides stability by not allowing the tibia to slide backwards on the femur.
As a team physician for professional teams as well as high school teams we commonly see significant ligament injuries to the knee. One of the more common injuries which can occur is a tear of the anterior cruciate ligament. This injury is often the result of either a hyperextension of the knee or a deceleration injury. The anterior cruciate ligament cannot be directly repaired, but instead will need to be reconstructed.
Arthroscopic surgery helps to provide for a more anatomic type of reconstruction for this ligament. The reconstruction choices for donor grafts are a cadaver graft, a person’s own hamstring tendons, or the bone tendon patella tendon. The procedure begins with an exam under anesthesia followed by a diagnostic arthroscopy. During the diagnostic portion of the arthroscopy, injuries to the meniscus and or articular cartilage can be handled with either repair or resection of the meniscus with possible transfer of articular cartilage from a non-weight bearing area to a damaged weight bearing area.
If the anterior cruciate ligament is torn then depending upon the age of the patient and the activity level to be achieved, choices of ligament donor grafts would either include autografts from the patient or allografts from a cadaver.
Position of the tunnels can be enhanced with instrumentation such as the flip cutter, which will allow a pin to be drilled from the outside of the knee to the inside to a set point. It will then become a remaining instrument by flipping a blade to form a drill for tunnel creation.
Enhanced interference fixation of the graft can be established with screws made of bio absorbable material including bone substitute. The screws actually become bone over a period of time.
Injuries to the knee ligaments should be evaluated as soon as possible. A history, physical exam, and x-rays are the beginning of the workup which may also include MRI study for further evaluation of the damage. A successful ACL reconstruction will allow your need to function more normally. It will also reduce your risk for further injury.