Your ACL and MCL are both ligaments in your knee. The two ligaments connect your femur (thigh bone) to your tibia (shin bone) and protect the menisci that cushion the knee joint. Knowing the signs and symptoms of a tear can help you identify which of these two ligaments is injured and receive appropriate treatment.
What is an ACL tear?
The anterior cruciate ligament, or ACL, is located in the middle of your knee and helps stabilize the joint. ACL injuries commonly occur while playing sports that involve sudden stops or changes in direction, such as basketball, soccer, tennis, or football.
Injuries can range from overextending the ligament to a full tear. A mild injury may strain the ligament but keep it intact. Moderate to severe injuries can cause a partial or full tear of the ligament. You will likely hear a “popping” noise if that type of injury occurs. You may experience swelling or be unable to put weight on the injured knee.
What is an MCL tear?
The MCL, or medial collateral ligament, runs long the inside of your knee and keeps the joint from over-extending. It also connects your shin to your thigh bone. Athletes who play high-contact sports like football or hockey may injure the MCL when colliding with another player. The MCL is often injured when the outer knee is hit very hard, causing strain on the inner knee.
When the knee is twisted, bent, or pushed to the side in an unnatural way, the ligament will stretch and result in a partial or full tear. You may hear a popping sound, followed by pain and swelling along the inside of the knee.
ACL vs MCL Symptoms
Both ACL and MCL tears can result in the following:
- A popping sound
- Pain or tenderness
- Knee feels unstable
- Unable to put weight on the knee
Although the symptoms are similar, a few key differences will help you identify whether the injury affected the ACL or MCL. An ACL tear will have a more distinctive and loud popping sound than an MCL tear.
Additionally, the location of your pain and swelling could indicate either an ACL or MCL tear. You will likely feel pain in the center of your knee during an ACL tear. Because the MCL is located on the side of your knee, the pain and swelling will be located on the inside of the knee structure rather than the middle.
Treatment and Recovery for ACL vs. MCL Tears
Immediately after injuring your knee, apply ice to the area, use a compression garment to stabilize the joint, and prop up your knee to elevate it until you can get medical treatment.
Dr. Heiden will evaluate the condition of your knee and guide you in rehabilitation. He will provide a stabilizing brace and may recommend crutches during the initial healing process.
Moderate to severe ACL tears can require surgery to resolve. In most cases, a graft is used to replace the torn part of the ligament. Recovery can take six months or more depending on the severity of the injury. Dr. Heiden will help you determine if surgery is necessary. An MCL tear rarely needs surgery and typically heals after approximately eight weeks of focused rehab. Heiden Orthopedics treats a range of ligament injuries, including ACL and MCL tears. Learn more about the knee anatomy and procedures.
For further information on ACL tears, read our article on ACL Tear Symptoms and Treatments.