ANTERIOR CRUCIATE LIGAMENT (ACL) INJURY
An ACL injury is damage to the anterior cruciate ligament (ACL), one of the major ligaments that stabilizes the knee.
The ACL connects the thigh bone (femur) to the shin bone (tibia) and helps prevent the shin bone from sliding too far forward and controls twisting movements of the knee.
ACL injuries range in severity:
- Grade 1: The ligament is stretched but not torn.
- Grade 2: The ligament is partially torn.
- Grade 3: The ligament is completely torn (the most common serious ACL injury).
Common causes
ACL injuries often occur during activities that involve:
- Sudden stops or changes in direction
- Pivoting or twisting on a planted foot
- Landing awkwardly from a jump
- Direct impact to the knee (such as during football or soccer)
Sports like basketball, soccer, skiing, and football have a higher risk of ACL injuries.
Symptoms
People with an ACL injury often experience:
- A loud “pop” or popping sensation in the knee
- Immediate pain
- Rapid swelling within a few hours
- Knee instability or the feeling that the knee is “giving way”
- Difficulty walking or bearing weight
How it’s diagnosed
A healthcare provider usually diagnoses an ACL injury by:
- Asking about how the injury happened
- Performing a physical examination of the knee
- Ordering imaging tests, such as an MRI, to confirm the injury and check for damage to other structures like the meniscus or cartilage.
Treatment
Treatment depends on the severity of the injury, your age, activity level, and goals:
- Non-surgical treatment: Rest, ice, compression, elevation (RICE), physical therapy, and sometimes a knee brace. This may be appropriate for partial tears or people who are less active.
- Surgical treatment: ACL reconstruction is often recommended for complete tears in people who want to return to sports or have persistent knee instability. Surgery is usually followed by several months of rehabilitation.
Recovery
- Mild sprains may heal in 2–8 weeks.
- After ACL reconstruction, returning to sports typically takes 9–12 months, depending on healing, strength, and rehabilitation progress.
If you experience a popping sensation, rapid swelling, or your knee feels unstable after an injury, it’s important to see a healthcare professional promptly for evaluation. Early diagnosis and appropriate treatment can help prevent further damage to the knee.
ZP