ACL Tears and Knee Arthroscopy

What is the ACL?

The most commonly injured ligament of the knee is the anterior cruciate ligament or ACL. The risk of injury is greater among those who participate in high-risk sports like football, basketball, soccer, and skiing. Around half of ACL injuries occur in combination with damage to the meniscus (cartilage pad), other ligaments, or other structures.

Most of the time, injury to the ACL occurs with pivoting, sidestepping, awkward landings or difficult cutting movements.

The knee is a hinged joint that is held together by four ligaments, one of them being the ACL. This structure runs diagonally in the middle portion of the knee to prevent the lower leg bone (the tibia) from sliding out in front of the thighbone (the femur). The ACL also serves to provide rotational stability of the knee.

What is Knee Arthroscopy?

One type of knee surgery is arthroscopy, a common surgical procedure in which a joint is viewed using a tiny camera. This camera looks into the knee through a small lens and projects an image on a TV monitor to allow the orthopedic specialist a clear view of what is inside the joint space.

An arthroscopic knee procedure allows the surgeon to diagnose and treat the knee injury at the same time. According to the American Orthopedic Society, more than 4 million knee arthroscopies are performed each year. This is a safe and effective way to treat the torn ACL.

Almost all arthroscopic knee surgical procedures are done on an outpatient basis. Knee arthroscopy is most commonly used for reconstruction of the torn ACL, trimming away pieces of torn cartilage, removing loose bone fragments or pieces of cartilage, and removing inflamed synovial tissue.

Your surgery center or hospital facility will contact you with specific details about your appointment. You will be asked to arrive an hour or two before the procedure and not to eat or drink after midnight the night before.

Once you are at the facility where the knee arthroscopic procedure will take place, a member of the anesthesia team will see you. Knee arthroscopy or ACL surgery is usually performed under regional, or general anesthesia. The anesthesia professional will help you decide which method is best for you.

The orthopedic specialist will make three small incisions in your knee. A sterile solution will be used to irrigate the knee joint to wash away any cloudy fluid. This helps your surgeon see your knee clearly and in great detail. If surgical treatment is required, your orthopedic surgeon will insert tiny instruments through another incision. These instruments might be trimmers, scissors, and motorized shavers.

ACL tears are repaired by the use of substitute grafts, usually made of tendon. The graft tissues often involve autograft, meaning it comes from the patient. Tendons commonly used are the patellar tendon or the hamstring tendon. During the procedure, the orthopedic specialist will often drill small bone tunnels into the tibia and femur to place the ACL graft in the same position as the torn ACL. The graft is held under tension and is fixed in place using screws, washers, posts, or staples.

Rehabilitation after ACL surgical reconstruction with arthroscopy is much faster than recovery from traditional open knee surgery. You will need to follow your orthopedic specialist’s instructions carefully. Be prepared for some swelling, so you will need to keep your knee elevated as much as possible the first couple of days after the procedure. Ice is usually recommended by the surgeon to take down swelling and help with the pain.

Dressing Care
Once the procedure is over, the doctor will cover your knee with a sterile dressing and you are to keep the incisions and this dressing clean and dry. Your orthopedic specialist will advise you on bathing and when to change the dressing.

Bearing Weight
After arthroscopic knee surgery to reconstruct the ACL, you will likely need crutches or some other assistive device for the first few days to prevent excessive swelling and bleeding into the knee. Your surgeon will tell you when it is safe to bear weight on your leg and foot.

Typically, you must wait 1 to 3 weeks before driving, depending on your doctor’s orders. The orthopedic specialist will base this decision on the knee that is involved, whether your car is an automatic or stick shift, the nature of your procedure, what type of medications you are taking, and how well you can control your knee.


About Jonathan Franklin

Jonathan Franklin, MD (Retired) Dr. Franklin is a board-certified orthopedic surgeon with a clinical focus in arthroscopic and reconstructive knee surgery, arthroscopic shoulder surgery, as well as knee replacement surgery. Dr. Franklin has a strong background in sports medicine, and treats many high school, as well as recreational and professional athletes for a wide variety of sports injuries.