How Long Does A Sprained Knee Take To Heal? | Recovery Time and Treatment Options for Every Sprain

Physical Therapist checking the sprained knee of a patient

The most common question related to knee sprains is: “How long does a sprained knee take to heal?”

It can take a few weeks or even months, depending on the severity of the sprain and the affected ligament.

Trust me, I know it’s frustrating. I know you want to get back to normal life as soon as possible. But, it’s imperative to respect the timeline of recovery to avoid re-injuring yourself.

I’ll give you some estimates for recovery, but keep in mind that these periods vary from person to person. Your knee ligaments may need more or less time to heal.

Use this as a guideline so you know what to expect!

How long does it take for a sprained knee to heal?

Grade 1 knee sprain: 4 weeks

We call this a mild sprain.

In this type of sprain, your ligaments can still keep your knee joint stable. They’re overstretched, but not torn.

Symptoms of a mild knee sprain include (1):

  • You can bear weight on the injured leg.
  • There’s mild swelling and/or bruising.
  • You can bend and straighten your knee joint with little to no pain.
  • You didn’t feel a “pop” at the moment of injury.
  • Your knee feels stable.

The treatment for a mild knee sprain includes (2):

Please go to a doctor if your pain or swelling increases or feel like your knee is giving out.

Grade 2 knee sprain: 10 weeks

This is a moderate sprain. The knee ligament is partially torn, so the knee joint can feel a little unstable.

Here, we have to reduce the load on the joint to allow the injury to heal.

Using crutches and/or wearing a knee brace for 3-6 can help achieve this. But, it also depends on the injured ligament and what your doctor considers best.

The remaining 4-7 weeks focus on restoring your joint’s strength and range of motion. This is best done with physical therapy.

Symptoms of a knee sprain grade 2 include (1):

  • Pain increases while bearing weight on the injured leg.
  • Localized swelling in the area of the affected ligament.
  • It’s painful to move the knee.
  • There may have been a “crack” or “pop” at the moment of injury.

The treatment for a moderate knee sprain includes:

  • Restrict movement – usually with a knee brace – to promote healing.
  • Use an elastic bandage and elevate the joint – this reduces swelling.
  • Ice your knee 2-3 times a day for 10 minutes to reduce pain.
  • Physical therapy to help you strengthen your knee and lower leg safely.

Patients may return to sports only when meeting the following criteria: full, painless knee motion, complete reduction of knee tenderness, and complete resolution of ligamentous laxity. – Yaras, 2021

Grade 3 knee sprain: 16 weeks

There’s a complete tear of the ligament, making this a severe sprain. This usually needs to get surgically repaired.

Ligaments prone to severe sprains during contact sports and car accidents include(1):

  • Anterior cruciate ligament (ACL)
  • Posterior cruciate ligament (PCL)

Patients usually wear a knee immobilizer for ~6 weeks after surgery. Physical therapy follows shortly after. But, sport-specific therapy might begin 4 months post-surgery.(1)

Symptoms of a severe knee sprain include :

  • A loud “pop” at the moment of injury.
  • Pain and swelling – can vary from person to person.
  • Bruising in the first 24 hours after injury.
  • Unstable knee, or like it’s “giving out.”
  • Can’t bear weight on the injured knee.

Treatment options for severe knee sprains include (1):

  • Surgery to repair the torn ligament.
  • Physical therapy. This helps promote healing, reduce swelling, and manage pain. It also helps you regain your strength, range of motion, and stability.
  • Rest, ice, medication.

What is a knee sprain?

It’s an injury where the ligament stretches more than it’s capable of, maybe to the point of tearing.

It’s a common diagnosis – it accounts for more than 40% of the injuries seen in the emergency department. (3)

Knee injuries were responsible for 49.4% of all athletic injuries that required surgery and complete ligament sprain was the most common diagnosis.Gray, 2015

The length of the recovery process will depend not only on the grade of the sprain but also on the affected ligament.

Anterior cruciate ligament (ACL)

The ACL is inside of the knee. Combined with the PCL, both form an X shape that helps stabilize the knee from within.

An ACL sprain can happen after jumping or twisting your knee suddenly. For example, changing directions while playing soccer. It’s the most commonly injured ligament of the knee. (4)

Symptoms of an ACL sprain include:

  • A sudden “pop” and like the knee gives out.
  • Swelling and bruising in the first 24 hours.
  • Difficulty walking.

Non-athletes or people with mild to moderate tears may benefit from non-operative treatment.

Undergoing operative treatment is a decision that’s based on several factors. But, generally, it’s best for active young people and athletes. Also, it may be useful if there’s any other associated injury, like a meniscus tear.

ACL sprains may take up to 18 months to fully recover. This period covers surgical repair and physical therapy. (4)

Posterior cruciate ligament (PCL)

The PCL is approximately twice as thick and as strong as the ACL, making it less prone to injury. (5)

A PCL injury usually happens when an extreme force pushes the shin bone on a flexed knee. For example, when the knee is forced into the dashboard during a car accident.

Symptoms of a PCL sprain include:

  • Pain and swelling on the back of your knee.
  • Worsening of symptoms when kneeling.
  • A recent car accident or falling on your knees.

Treatment is usually non-operative.

Conservative treatment is generally useful for non-athletes with mild symptoms.

But, operative treatment may also be necessary.

This can be the case if your PCL sprain comes with severe symptoms. This includes dislocation or pain walking downhill.

Your doctor might also recommend surgery for chronic tears. Or, if your injuries come with meniscus tears.

It generally takes up to 9 months to recover after surgery. (5)

Medial collateral ligament (MCL)

The MCL is on the inner side of the knee. A sprain can happen after the knee bends inward suddenly, like in skiing.

Symptoms of an injured MCL include:

  • Tenderness on the inner side of the knee.
  • A “pop” at the moment of injury.
  • Difficulty walking.
  • Knee instability.

The treatment is generally conservative, taking at least 6 weeks. The surgical route is usually reserved for professional athletes. (6)

Lateral collateral ligament (LCL)

The LCL is on the outside of the knee. It’s commonly sprained after a direct blow on the inner side of the knee with the leg extended.

Symptoms of an injured LCL include (1):

  • Tenderness and bruising on the outer side of the knee.
  • Difficulty walking.
  • Numbing or tingling on the outer side of the lower leg.

The treatment is mostly conservative unless there’s a severe sprain. If so, the ligament might need to be surgically repaired. (1)

It can take at least 4 months to recover after surgery. (1)

FAQs

Can you walk on a knee sprain?

Most people can walk with a grade 1 or 2 sprain. You might need crutches to reduce the pressure on the joint and let it heal properly.

Check with your doctor first for individual recommendations.

What is the fastest way to heal a knee sprain?

This will depend on the characteristics of your sprain. In general, the fastest way is to follow the medical advice of your healthcare providers and go to physical therapy.

Do knee sprains heal on their own?

Mild to moderate sprains will likely heal naturally, or may need some extra help with physical therapy, bracing, etc.

Severe sprains may need surgery.

What increases my risk for a knee sprain?

Playing high-contact sports, having a previous knee injury, and muscle weakness may increase your risk for a knee sprain. (1, 7, 8)

What’s the difference between knee sprains and strains?

“Sprain” refers to ligaments, “strain” refers to tendons or muscles.

Conclusion: How long will a sprained knee take to heal?

The answer to: “how long can a sprained knee take to heal?” will depend on the severity of the sprain, which ligament was injured, and your treatment method.

It can take anywhere from 4 weeks to 18 months.

The good news is that the general outlook is positive!

Just respect the timeline of recovery and follow the recommendations of your physical therapist. We’re trained to help you recover safely from these types of injuries.

Resources

  1. Yaras, Reed et al. “Lateral Collateral Ligament Knee Injuries.” [Updated 2021 May 4]. Statpearls. Retrieved on June 15, 2021 from: https://www.ncbi.nlm.nih.gov/books/NBK560847/
  2. “Sprains and strains.”[Last reviewed: 12 January 2018]. NHS. Retrieved on June 15, 2021 from: https://www.nhs.uk/conditions/sprains-and-strains/
  3. Gray, Aaron M, and William L Buford. “Incidence of Patients With Knee Strain and Sprain Occurring at Sports or Recreation Venues and Presenting to United States Emergency Departments.” Journal of athletic training vol. 50,11 (2015): 1190-8. doi:10.4085/1062-6050-50.11.06
  4. Evans, Jennifer et al. “Anterior Cruciate Ligament Knee Injuries.” [Updated 2021 Feb 19]. Statpearls. Retrieved on June 15, 2021 from: https://www.ncbi.nlm.nih.gov/books/NBK499848/
  5. Raj, Marc et al. “Posterior Cruciate Ligament Knee Injuries.” [Updated 2021 Jan 22]. Statpearls. Retrieved on June 15, 2021 from: https://www.ncbi.nlm.nih.gov/books/NBK430726/
  6. Naqvi, Usker et al. “Medial Collateral Ligament Knee Injuries.” [Updated 2021 Mar 17]. Statpearls. Retrieved on June 15, 2021 from: https://www.ncbi.nlm.nih.gov/books/NBK431095/
  7. Fulton, Jessica et al. “Injury risk is altered by previous injury: a systematic review of the literature and presentation of causative neuromuscular factors.” International journal of sports physical therapy vol. 9,5 (2014): 583-95.
  8. Pfeifer, Craig E et al. “RISK FACTORS ASSOCIATED WITH NON-CONTACT ANTERIOR CRUCIATE LIGAMENT INJURY: A SYSTEMATIC REVIEW.” International journal of sports physical therapy vol. 13,4 (2018): 575-587.