What are the symptoms of Anterior Cruciate Ligament (ACL) Tear?

Common symptoms include: Sudden popping sound or sensation at the time of injury; Rapid onset of knee swelling, typically within hours of injury; Significant pain, often severe initially; Loss of range of motion, particularly full extension; Feeling of knee instability or giving way.

How is Anterior Cruciate Ligament (ACL) Tear diagnosed?

Diagnosis typically involves: Medical history focusing on mechanism of injury and symptoms; Physical examination including Lachman test, anterior drawer test, and pivot shift test; Assessment of range of motion, swelling, and ligament stability; MRI is the imaging study of choice for confirming ACL tears and identifying associated injuries.

Anterior Cruciate Ligament (ACL) Tear

Also known as: torn ACL, ACL rupture, anterior cruciate ligament tear, complete ACL tear, ACL sprain, ACL knee ligament tear

Last updated: December 18, 2024

An anterior cruciate ligament (ACL) tear is an injury to a major knee ligament that helps provide rotational stability and limits the tibia from sliding forward relative to the femur. It commonly occurs in sports with sudden stops, pivoting, or jumping, and can be partial or complete. Symptoms may include a sudden pop and rapid swelling within hours. Treatment options include rest, ice, compression, and elevation (RICE). Many people return to high-level sports after ACL reconstruction and rehabilitation.

Key Facts

•An anterior cruciate ligament (ACL) tear is an injury to one of the major ligaments of the knee that provides rotational stability and helps prevent the tibia from sliding forward relative to the femur
•Sudden popping sound or sensation at the time of injury
•Diagnosed through history, physical exam, and imaging
•First-line treatment includes exercise, weight management, and activity modification

What It Is

An anterior cruciate ligament (ACL) tear is an injury to one of the major ligaments of the knee that provides rotational stability and helps prevent the tibia from sliding forward relative to the femur. ACL tears commonly occur during sports involving sudden stops, pivoting, or jumping, and may range from partial to complete ruptures.

Affected Anatomy

This condition affects several structures in and around the joint:

•Anterior cruciate ligament (connects femur to tibia)
•Knee joint capsule
•Menisci (may be injured concomitantly)
•Other knee ligaments (MCL, PCL, LCL may also be involved)
•Articular cartilage of the knee
•Surrounding muscles including quadriceps and hamstrings

Common Symptoms

Symptoms can vary in intensity and may change over time. Common experiences include:

•Sudden popping sound or sensation at the time of injury
•Rapid onset of knee swelling, typically within hours of injury
•Significant pain, often severe initially
•Loss of range of motion, particularly full extension
•Feeling of knee instability or giving way
•Difficulty bearing weight on the affected leg
•Tenderness along the joint line
•Bruising around the knee may develop

Causes and Risk Factors

Multiple factors can contribute to the development of this condition:

Causes

•Non-contact pivoting or cutting movements during sports
•Sudden deceleration or stopping
•Landing awkwardly from a jump
•Direct impact or collision to the knee
•Hyperextension of the knee
•Rapid direction changes while running

Risk Factors

•Participation in high-risk sports such as soccer, basketball, football, and skiing
•Female athletes may have higher rates of ACL injury compared to males in similar sports
•Previous ACL injury increases risk of subsequent injury
•Muscle imbalances or weakness, particularly in hamstrings relative to quadriceps
•Inadequate neuromuscular control or landing mechanics
•Playing on artificial turf may increase risk in some studies
•Hormonal factors may influence injury risk in some individuals

How It's Diagnosed

Diagnosis typically involves a combination of clinical assessment and imaging studies:

•Medical history focusing on mechanism of injury and symptoms
•Physical examination including Lachman test, anterior drawer test, and pivot shift test
•Assessment of range of motion, swelling, and ligament stability
•MRI is the imaging study of choice for confirming ACL tears and identifying associated injuries
•X-rays may be obtained to rule out fractures
•Evaluation for concurrent meniscal or other ligament injuries

Treatment Options

Treatment approaches range from conservative measures to surgical interventions, often starting with the least invasive options:

Self-Care and Activity Modification

•Initial management with rest, ice, compression, and elevation (RICE protocol)
•Bracing may provide stability during certain activities
•Activity modification, particularly avoiding pivoting and cutting sports

Physical Therapy and Exercise

•Physical therapy focusing on range of motion restoration and strengthening

Medications

•Pain management with NSAIDs or other medications

Surgery

•Non-surgical management may be appropriate for some lower-demand patients or partial tears
•ACL reconstruction surgery may be recommended for active individuals who desire return to pivoting sports
•Rehabilitation following surgery typically spans several months

Prognosis and Recovery

The course of this condition varies between individuals:

•Many individuals can return to high-level sports following successful ACL reconstruction and rehabilitation
•Return to sport typically occurs 6 to 12 months after reconstruction, depending on recovery and sport demands
•Risk of re-injury or contralateral injury exists, particularly in younger athletes
•Some individuals may develop knee osteoarthritis over time regardless of treatment approach
•Non-surgical management may be successful for lower-demand activities in selected patients

ACL Reconstruction(Procedure)
Meniscus Tear(Condition)
Knee Osteoarthritis(Condition)

Frequently Asked Questions

Treatment options range from conservative measures to surgical interventions, including: Initial management with rest, ice, compression, and elevation (RICE protocol); Pain management with NSAIDs or other medications; Physical therapy focusing on range of motion restoration and strengthening; Bracing may provide stability during certain activities; Activity modification, particularly avoiding pivoting and cutting sports.