Traumatic Anterior cruciate ligament (ACL) injury

Last updated: February 8, 2026Reviewed date: February 8, 2026Reading time: 4 min read

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Cruciate ligament injury - anterior; ACL injury; Knee injury - anterior cruciate ligament (ACL) An anterior cruciate ligament injury is the over-stretching or tearing of the anterior cruciate ligament (ACL) in the knee. A tear may be partial or complete. Considerations The knee joint is...

For severe symptoms, danger signs, pregnancy, child illness, or sudden worsening, seek urgent medical care.

বাংলা রোগী নোট এখনো যোগ করা হয়নি। পোস্ট এডিটরে “RX Bangla Patient Mode” বক্স থেকে সহজ বাংলা সারাংশ যোগ করুন।

এই তথ্য শিক্ষা ও সচেতনতার জন্য। এটি ডাক্তারি পরীক্ষা, রোগ নির্ণয় বা প্রেসক্রিপশনের বিকল্প নয়।

Article Summary

Key Takeaways

This article explains Considerations in simple medical language.
This article explains Causes in simple medical language.
This article explains Symptoms in simple medical language.
This article explains First Aid in simple medical language.

Educational health guideWritten for patient understanding and clinical awareness.

Reviewed content workflowUse writer and reviewer profiles for stronger trust.

Emergency safety firstUrgent warning signs are highlighted below.

Seek urgent medical care if you notice

These warning signs are general safety guidance. Local emergency numbers and clinical judgment should always come first.

Severe symptoms, breathing difficulty, fainting, confusion, or rapidly worsening illness.
New weakness, severe pain, high fever, or symptoms after a serious injury.
Any symptom that feels urgent, unusual, or unsafe for the patient.

Emergency now

Use emergency care for severe, sudden, rapidly worsening, or life-threatening symptoms.

See a doctor

Book a professional medical evaluation if symptoms persist, worsen, recur often, affect daily activities, or occur in a high-risk patient.

Learn safely

Use this article to understand possible causes, tests, treatment options, prevention, and questions to ask your clinician.

Cruciate ligament injury – anterior; ACL injury; Knee injury – anterior cruciate ligament (ACL)

An anterior cruciate ligament injury is the over-stretching or tearing of the anterior cruciate ligament (ACL) in the knee. A tear may be partial or complete.

Considerations

The knee joint is located where the end of the thigh bone (femur) meets the top of the shin bone (tibia).

Four main ligaments connect these two bones:

Medial collateral ligament (MCL) runs along the inside of the knee. It prevents the knee from bending in.
Lateral collateral ligament (LCL) runs along the outside of the knee. It prevents the knee from bending out.
Anterior cruciate ligament (ACL) is in the middle of the knee. It prevents the shin bone from sliding out in front of the thigh bone.
Posterior cruciate ligament (PCL) works with the ACL. It prevents the shin bone from sliding backwards under the femur.

Women are more likely to have an ACL tear than men.

Causes

An ACL injury can occur if you:

Get hit very hard on the side of your knee, such as during a football tackle
Overextend your knee joint
Quickly stop moving and change direction while running, landing from a jump, or turning

Basketball, football, soccer, and skiing are common sports linked to ACL tears.

ACL injuries often occur with other injuries. For example, an ACL tear often occurs along with tears to the MCL and the shock-absorbing cartilage in the knee (meniscus).

Most ACL tears occur in the middle of the ligament, or the ligament is pulled off the thigh bone. These injuries form a gap between the torn edges, and do not heal on their own.

Symptoms

Early symptoms:

A “popping” sound at the time of injury
Knee swelling within 6 hours of injury
Pain, especially when you try to put weight on the injured leg

Those who have only a mild injury may notice that the knee feels unstable or seems to “give way” when using it.

First Aid

See your health care provider if you think you have an ACL injury. Do not play sports or other activities until you have seen a provider and have been treated.

Your provider may send you for an MRI of the knee. This can confirm the diagnosis. It may also show other knee injuries.

First aid for an ACL injury may include:

Raising your leg above the level of the heart
Putting ice on the knee
Pain relievers, such as nonsteroidal infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">inflammation, pain, or swelling. সহজ বাংলা: প্রদাহ/ফোলা/ব্যথা কমায়।" data-rx-term="anti-inflammatory" data-rx-definition="Anti-inflammatory means reducing inflammation, pain, or swelling. সহজ বাংলা: প্রদাহ/ফোলা/ব্যথা কমায়।">anti-inflammatory drugs (such as ibuprofen)

You also may need:

Crutches to walk until the swelling and pain get better
Physical therapy to help improve joint motion and leg strength
Surgery to rebuild the ACL

Some people can live and function normally with a torn ACL. However, most people complain that their knee is unstable and may “give out” with physical activity. Unrepaired ACL tears can lead to further knee damage. You are also less likely to return to the same level of sports without the ACL.

Do Not

Do NOT move your knee if you have had a serious injury.
Use a splint to keep the knee straight until you see a doctor.
Do NOT return to play or other activities until you have been treated.

When to Contact a Medical Professional

Call your provider right away if you have a serious knee injury.

Get immediate medical attention if the foot is cool and blue after a knee injury. This means that the knee joint may be dislocated, and blood vessels to the foot may be injured. This is a medical emergency.

Prevention

Use proper techniques when playing sports or exercising. Some college sports programs teach athletes how to reduce the stress placed on the ACL.

The use of knee braces during vigorous athletic activity (such as football) is controversial. It has not been shown to reduce the number of knee injuries, and not specifically ACL injuries.

Safety note: This is not a prescription or diagnosis. For severe symptoms, pregnancy danger signs, children with serious illness, chest pain, breathing difficulty, stroke-like weakness, or major injury, seek urgent care.

Which doctor may help?

Start with a registered doctor or the nearest qualified health center.

What to tell the doctor

Write when the problem started and how it changed.
Bring old prescriptions, investigation reports, and current medicines.
Write allergies, pregnancy status, diabetes, kidney/liver disease, and major past illnesses.
Bring one family member if the patient is weak, elderly, confused, or a child.

Questions to ask

What is the most likely cause of my symptoms?
Which danger signs mean I should go to hospital quickly?
Which tests are necessary now, and which can wait?
How should I take medicines safely and what side effects should I watch for?
When should I come for follow-up?

Tests to discuss

Vital signs: temperature, pulse, blood pressure, oxygen saturation
Basic physical examination by a clinician
CBC, urine test, blood sugar, or imaging only when clinically needed

Avoid these mistakes

Do not use antibiotics, steroid tablets/injections, or strong painkillers without proper medical advice.
Do not hide pregnancy, kidney disease, ulcer, allergy, or blood thinner use.
Do not delay emergency care when danger signs are present.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

Safe first steps

Rest, drink safe water, and observe symptoms carefully.
Keep a written note of symptoms, duration, temperature, medicines already taken, and allergy history.
Seek medical care quickly if symptoms are severe, worsening, or unusual for the patient.

OTC medicine safety

For mild pain or fever, ask a registered pharmacist or doctor before using common over-the-counter pain/fever medicines.
Do not combine multiple pain medicines without advice, especially if you have kidney disease, liver disease, stomach ulcer, asthma, pregnancy, or take blood thinners.
Do not give adult medicines to children unless a qualified clinician advises it.

Avoid these mistakes

Do not start antibiotics without a proper medical decision.
Do not use steroid tablets or injections casually for quick relief.
Do not delay emergency care because of home remedies.

Get urgent help if

Severe symptoms, confusion, fainting, breathing difficulty, chest pain, severe dehydration, or sudden weakness need urgent medical care.

Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

For rural patients and family caregivers

Patient health record and symptom diary

Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Doctor / qualified healthcare provider

Tests to discuss with doctor

Basic vital signs: temperature, pulse, blood pressure, oxygen level if needed
Relevant blood, urine, imaging, or specialist tests only after clinical assessment

Questions to ask

What is the most likely cause of my symptoms?
Which warning signs mean I should go to emergency care?
Which tests are really needed now?
Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Go to emergency care if you notice:

Severe or rapidly worsening symptoms
Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration

Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.

Step 1
Check danger signs first
If danger signs are present, seek emergency care and do not wait for online information.
Step 2
Record the symptom story
Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.
Step 3
Visit a qualified clinician
A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.
Step 4
Do only useful tests
Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.
Step 5
Follow up and return early if worse
If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips

Take a written symptom diary and all previous prescriptions/test reports.
Do not hide medicines already taken, even herbal or over-the-counter medicines.
Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

RX Patient Help

Ask a health question safely

Write your symptom story. A health professional or site editor can review it before any answer is prepared. This box is not for emergency care.

Emergency first: Severe chest pain, breathing trouble, unconsciousness, stroke signs, severe injury, heavy bleeding, or rapidly worsening symptoms need urgent local medical care now.

Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

Add references, clinical guidelines, textbooks, journal articles, or trusted medical sources here. You can edit this area from the RX Article Professional Blocks panel.

Traumatic Anterior cruciate ligament (ACL) injury

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