ACL Tears

ACL injuries (also called ACL ruptures or tears) are among the most common knee injuries in both professional and amateur athletes, especially those participating in sports that involve sudden stops, jumps, or changes in direction, such as tennis, basketball, football, skiing, and soccer. Seventy percent of ACL injuries are non-contact injuries, whereas 30% are the result of direct impact.

ACL injuries often result from high-impact or rapid-motion activities and involve:

• Sudden changes in direction or cutting maneuvers: Abrupt shifts in movement can place excessive strain on the ACL.
• Rapid slowing down or stopping: Decelerating quickly can lead to hyperextension or excessive forward movement of the tibia relative to the femur, stressing the ACL.
• Awkward landing from a jump or a fall: Landing with the knees extended or with the knees angled inward can cause excessive force through the ACL.
• Pivoting on a firmly planted foot: Twisting motions when the foot is planted and the knee is slightly bent can injure the ACL.
• Direct collision or impact: A direct blow to the side of the knee, such as during a football tackle or any movement that causes the knee to move beyond its normal range.

• Pop: Individuals often report hearing or feeling a popping sensation at the time of the injury.
• Pain: Severe pain immediately after the injury. The pain is typically located in the knee’s middle, making it difficult to continue sports or activities.
• Swelling: Rapid swelling occurs within hours of the injury due to bleeding within the joint. Pain and swelling may resolve within days to weeks, but knee instability may remain.
• Loss of range of motion: Pain and swelling can make bending or straightening the knee difficult.
• Weakness: Particularly noticeable in the quadriceps muscle group (front of the thigh)
• Difficulty walking: Typically due to pain, swelling, and muscle weakness.
• Knee instability: the sense that the knee will give way or not trust the knee when doing cutting or pivoting activities.

Your UCSF Women’s Sports Medicine Center physician will diagnose an ACL injury based on clinical evaluation and imaging studies. They will review your medical history and inquire about previous knee injuries, how the current injury occurred, and the symptoms being experienced.

They will perform a detailed physical exam assessing swelling, tenderness, range of motion, and testing the integrity of the ligament. They will perform specific tests to check the stability of the knee joint and assess if the ACL is torn,

Imaging studies such as X-rays are necessary to rule out broken bones or fractures, and an MRI is used to assess soft tissues such as the ACL and check for associated injuries to the other ligaments of the knee, meniscus (cartilage cushions between the femur and tibia), cartilage, and bone.

With the information gathered from the clinical exam and the imaging studies, they will diagnose and determine the injury’s severity.

ACL injuries are treated individually, depending on the level and type of activity desired by the patient. Non-operative care is an option for partial tears or complete tears or ruptures in those who participate in straight-in-line activities such as walking, cycling, and sometimes running. Physical therapy for several months and bracing are often recommended.

As the ACL is essential to stabilize the knee for cutting and pivoting activities, those who participate in sports that involve these motions are candidates for ACL reconstruction surgery. Your surgeon can discuss ACL reconstruction surgery options, recovery, and outcomes with you in detail.