ACL Tear !
An ACL tear is a partial or complete tear of the anterior cruciate ligament inside the knee, usually from a sudden stop, pivot or bad landing.
Updated 2026-10-23
Structures involved
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In the clinical exam
Why it happens
- Connective tissue proper: cells and fibres
- Synovial joints: capsule, synovial membrane and articular cartilage
What it is
Partial or complete tear of the anterior cruciate ligament, usually from a sudden stop, pivot or awkward landing.
Causes
- Sudden deceleration or change of direction
- Landing from a jump
- Often occurs with meniscus or MCL injury
Classification
- Partial tear
- Complete tear
Symptoms and signs
- A pop at the moment of injury
- Swelling that develops within hours
- Feeling of the knee giving way or instability
- Difficulty pivoting or cutting
Diagnosis
- Clinical
- Lachman test, anterior drawer, pivot-shift test
- Imaging
- MRI confirms the tear and checks other structures; X-ray rules out fracture
Treatment
- Rehabilitation
- Physical therapy to strengthen surrounding muscles, activity changes, and sometimes a brace.
- Surgical
- ACL reconstruction with a tendon graft.
Related conditions
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Anterior Cruciate Ligament Knee Injury (StatPearls (NCBI Bookshelf), 2024).
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Representative model, for educational purposes only.
