The knee has 4 important ligaments – two cruciate ligaments and two collateral ligaments.
The cruciate ligaments are found inside the knee joint and They cross each other to form an "X" with the anterior cruciate ligament in front and the posterior cruciate ligament in back. The cruciate ligaments control the back and forth motion of your knee.
The collateral ligaments found on the sides of your knee. The medial collateral ligament is on the inside and the lateral collateral ligament is on the outside. They control the sideways motion of your knee and brace it against unusual movement.
Ligaments are tough, nonstretchable fibers that hold your bones together. A tear to the anterior cruciate ligament (ACL) of your knee joint is among the most common sport-related injuries.
The ACL can tear when it’s stretched beyond its normal range. This typically happens by sudden twisting movements, slowing down from running, or landing from a jump. You may hear a popping sound at the time of injury. Your knee may give way and begin to swell and hurt.
Other ligaments and cartilages in the knee may be damaged at the time of ACL injury. Most commonly the medial collateral ligament (MCL) may tear and either the medial or lateral meniscus may tear. This may result in locking of the knee joint.
- Pain with swelling. Within 24 hours, your knee will swell. If ignored, the swelling and pain may resolve on its own. However, if you attempt to return to sports, your knee will probably be unstable and you risk causing further damage to the cushioning cartilage (meniscus) of your knee.
- Loss of full range of motion
- Tenderness along the joint line
- Discomfort while walking
Examination of the knee will reveal any instability – the tests used to assess the ACL are the anterior draw, Lachmann’s and pivot shift test.
An x-ray is taken to exclude a fracture and occasionally an MRI scan is arranged to further assess the knee joint. It is quite common to see bone bruising on the MRI scan. Occasionally there will be an associated tear of either of the menisci which is amenable to surgical repair – this should be undertaken as soon as possible as delay may compromise the results of repair.
Treatment for an ACL tear (see attached pdf link) will vary depending upon the patient's individual needs. For example, the young athlete involved in agility sports will most likely require surgery to safely return to sports. The less active, usually older, individual may be able to return to a quieter lifestyle without surgery.
The main stay of non surgical treatment is physiotherapy. ACL rehabilitation programme by a specialist physiotherapist will help restore function of the knee and strengthen the leg.
If the ACL tear does lead to debilitating symptoms then a surgical reconstruction is required. The ACL cannot be repaired and therefore has to be replaced by a tissue graft.
Grafts can be obtained from several sources. This is either the patellar tendon or the Hamstring tendons. Sometimes a quadriceps tendon, which runs from the kneecap into the thigh, is used. Finally, cadaver graft (allograft) can be used.
Surgery to rebuild an anterior cruciate ligament is done with an arthroscope using small incisions. Arthroscopic surgery is less invasive. The benefits of less invasive techniques include less pain from surgery, less time spent in the hospital, and quicker recovery times.
The patient is admitted on the day of surgery. The surgery itself takes around 1 to 2 hours. One night stay me be required and the patient goes home on crutches.
After surgery, the physiotherapist first focuses on returning motion to the joint and surrounding muscles. This is followed by a strengthening program designed to protect the new ligament. This strengthening gradually increases the stress across the ligament. The final phase of rehabilitation is aimed at a functional return tailored for the athlete's sport. It can be upto 6 – 9 months before the patient returns back to the sports and other high level activities.