Knee Ligament Injuries

Your knee is the largest joint in your body and is essential to movement. There are two sets of ligaments that give your knee its stability: the cruciate and collateral ligaments.

The two cruciate ligaments – derived from the word crux, meaning cross and crucial – are located inside the knee joint. They are so named because they crisscross each other, forming an “X.” The cruciate ligament at the front of the knee is the anterior cruciate ligament (ACL), while the posterior cruciate ligament (PCL) is located behind the ACL.

Together they connect the thighbone (femur) to the shinbone (tibia), holding the knee joint tightly in place when you bend or straighten your leg. This stability is critical for proper knee joint movement.

The collateral ligaments are located on the inner and outer sides of the knee joint. The medial collateral ligament (MCL) connects the thighbone to the shinbone on the inside of the knee. The lateral collateral ligament (LCL) connects the thighbone to the other bone in the lower part of your leg (fibula) on the outer side of the knee.

They both provide stability and keep the knee from moving too far to one side or the other. An injury to the MCL is usually caused by a blow to the outside of the knee, resulting in a sharp pain on the inside of the knee. It is more likely to be injured than the LCL.

The orthopedic doctors at the Center for Orthopaedic Surgery and Sports Medicine in San Antonio are experts at diagnosing and treating knee ligament injuries. Learn more below.

ACL Injuries and Treatment

The purpose of the ACL is to prevent the shinbone from sliding forward beneath the thighbone. It can be injured during certain sports or normal activities, such as changing direction suddenly, slowing down when running, landing from a jump, or by direct contact, such as getting tackled.

You may not feel any immediate pain if you injure your ACL. However, you might hear a popping sound and feel your knee suddenly give out from under you. After a few hours, your knee will swell, and you’ll feel pain trying to stand up. If that happens, apply ice to control the swelling and elevate your knee until you meet with an orthopedic doctor.

Whatever you do, don’t walk or run with an injured ACL, as you can damage the cushioning cartilage in the knee.

Your orthopedist will likely order an X-ray and MRI to help assess the degree of damage to your ACL, and he may recommend arthroscopic surgery to examine the inside of the joint.

Treatment will depend on the extent of the injury. A partial ACL tear in which the knee is still stable may heal with conservative treatment such as rest, medication, physical therapy, and a brace to provide stability. A nonoperative approach may also be recommended due to a patient’s age or overall low activity level.

If you have a complete tear of the ACL, if you experience knee instability with either a partial or complete ACL tear, or if you are an athlete, your doctor will likely recommend surgery.

The procedure, called ACL reconstruction, is typically performed through arthroscopy. The surgeon will take a strip of tendon from the patient’s knee or hamstring muscle, pass it through the inside of the joint, and use it to secure the thighbone and shinbone. Following surgery, exercise and rehabilitation are prescribed to strengthen the muscles and restore full joint mobility.

PCL Injuries and Treatment

The PCL is not injured as frequently as the ACL, although PCL sprains do occur when the ligament is pulled or stretched too far as a result of a blow to the front of the knee, or a simple misstep.

PCL injuries disrupt knee joint stability due to the shinbone sagging backwards. When that happens, the ends of the thighbone and shinbone rub directly against each other. This causes wear and tear to the thin, smooth articular cartilage, which can lead to arthritis in the knee.

PCL tears rarely cause instability in the knees, so surgery is typically not necessary. Many athletes can return to their sport after a course of physical therapy. However, if the injury causes a piece of bone to dislodge from the top of the shinbone, surgery would be needed to reattach the ligament.

Collateral Ligament Injuries and Treatment

A small tear to the medial collateral ligament (MCL) can be treated using the RICE method – resting the knee to give the ligament sufficient time to heal; applying ice two or three times per day for 15 to 20 minutes; compressing the injury with a bandage or brace to limit swelling; and elevating the knee when possible.

You may require surgery if the collateral ligament is completely torn or damaged to the extent that it cannot heal on its own. Either way, surgical repair followed by physical therapy is usually successful in restoring knee stability and enabling patients to resume their previous levels of activity.

If you have knee pain and think you might have a knee ligament injury, make an appointment with one of our specialists at the Center for Orthopaedic Surgery and Sports Medicine in San Antonio. Call us at (210) 692-7400 or use our convenient online form to request an appointment.