ACL Tear
A plain-language overview of anterior cruciate ligament tear.
- Where
- Knee (ligament)
- Common signs
- Pop, swelling, giving way
- Options
- Rehab or ACL reconstruction
- Urgent?
- Severe pain, deformity, or numbness: seek care promptly.
Overview
An ACL tear is an injury to the anterior cruciate ligament, one of the main ligaments that keeps the knee stable. It is one of the most common knee injuries in sports.
Adapted from AAOS OrthoInfo, the patient education site of the American Academy of Orthopaedic Surgeons, and rewritten in plain language.
Anatomy
Four main ligaments connect the thighbone (femur) to the shinbone (tibia). The ACL runs diagonally through the middle of the knee and keeps the shinbone from sliding forward and rotating too far under the thighbone.
Causes
- Sudden stops or changes in direction (cutting and pivoting)
- Landing awkwardly from a jump
- Direct contact or collision, such as a tackle
- Common in soccer, basketball, football, skiing, and military training
Symptoms
- A popping sound or feeling at the time of injury
- Swelling within a few hours
- Pain and trouble putting weight on the leg
- Loss of full motion
- A sense that the knee shifts or gives way, especially with pivoting
Doctor exam & imaging
Your doctor will ask how the injury happened and examine the knee, comparing it to the other side. Special stability tests check how much the shinbone moves forward. X-rays look for fractures, and an MRI shows the ACL and other structures such as the meniscus and cartilage, which are often injured at the same time.
Treatment
Nonsurgical treatment
Some people with lower activity demands, or whose knee feels stable, do well with a brace and physical therapy focused on strength and balance. Nonsurgical care may also be considered when the knee does not give way during the activities a person wants to do.
Surgical treatment
A torn ACL usually does not heal on its own well enough for pivoting sports. ACL reconstruction replaces the torn ligament with a tissue graft, either from your own body (such as patellar tendon, hamstring, or quadriceps tendon) or from a donor. It is done arthroscopically through small incisions. Other injuries, like meniscus tears, may be treated during the same surgery.
Dr. Gee's published work includes ACL repair, graft choice, and fixation techniques; see Research.
Recovery & return to activity
Rehabilitation is a key part of recovery. Early goals are reducing swelling and regaining motion, followed by progressive strengthening, balance, and sport-specific training. Return to cutting and pivoting sports usually takes many months and is based on strength and function testing, not just time.
When to seek care
- The knee gives way or locks
- You cannot bear weight
- Swelling or pain is severe or getting worse
- Numbness, a cold foot, or a visible deformity (seek care right away)
In an emergency, call 911.