Common knee injuries vary from minor falls which may settle quickly to major accidents which may take months to recover from.
Some injuries result from massive forces going through the knee, whereas others may be the result of simply twisting slightly wrong.
The most common knee injuries fall into four groups:
The knee ligaments and cartilage are the structures most frequently damaged.
Here, we look at nine of the most common knee injuries, including how they occur, the symptoms for each one and the best knee injury treatment options. Once you've identified your knee injury, you can find out loads more detailed information by visiting the relevant section.
Knee ligament injuries can affect any of the four knee ligaments. Knee ligaments are usually injured either by sudden twisting movements, or when a great deal of force goes through part of the knee e.g. from a sporting tackle. Ligament injuries are the most common knee injuries in sports.
There are four ligaments in the knee, which work in the pairs. The anterior cruciate ligament and posterior cruciate ligament control the forwards and backwards movement of the knee and are really important for providing stability. The medial and lateral collateral ligaments provide sideways stability for the knee.
What is an ACL Knee Injury: Anterior cruciate ligament gets overstretched and tears or ruptures
Causes: Knee bending the wrong way, pushing back too far or twisting of the knee
Immediate Symptoms: Popping sound, swelling, pain, giving way
Long Term Problems: Lack of stability with pivoting and twisting
ACL Knee Injury Treatment: Exercise rehab and/or surgery. Visit the ACL Injuries
section for more information.
What is an MCL Tear: Damage to some or all of the fibres of the medial collateral ligament on the inner side of the knee
Causes: Force through the outside of the knee e.g. tackle, sudden twisting of the knee e.g. skiing
Symptoms: Inner knee pain, swelling, instability, difficulty bending the knee
MCL Knee Injury Treatment: PRICE, exercises, knee brace. Visit the
section to find out more
What is a PCL Knee Injury: Tear of the Posterior Cruciate Ligament that sits inside the knee joint. One of the less common knee injuries
Causes: A force through the top of the shin bone causing the knee to bend backwards e.g. car accident or fall on to a bent knee
Immediate Symptoms: Usually fairly mild pain and swelling. Often not noticed immediately. The shin bone tends to drop back from its normal position as seen in the picture here
Long Term Problems: Instability, particularly with activities when the knee is bent e.g. stairs, problems with running
PCL Knee Injury Treatment: Knee brace, physical therapy and/or surgery. Visit the PCL Injuries
section for more information.
What is a Knee Sprain: Over-stretching any of the knee ligaments which tears some of the fibres. This is one of the most common knee injuries
Causes: sudden force through the knee or sudden twisting
Symptoms: knee pain, swelling, instability, difficulty bending and straightening the knee
One of the most common knee injuries is damage to the knee cartilage.
The knee joint is lined with two types of cartilage, articular cartilage which lines the bones, and then a second special layer of cartilage known as the meniscus. The meniscus works like special cushioning to reduce the force going through the knee bones.
What is a Knee Cartilage Injury: Tear in the cartilage, aka meniscus, lining the knee joint. Meniscus tears are one of the most common knee injuries
Causes: Suddenly - force through the knee or sudden twisting of the knee, or gradually - through wear and tear e.g.
Symptoms: knee pain, swelling, locking, instability, difficulty straightening the knee, difficulty walking
Knee Cartilage Injury Treatment: PRICE, exercises, knee brace, tubigrip, sometimes requires surgery. Can take a long time to heal - see the
section to find out more.
Another group of common knee injuries is muscle damage. If the muscles around the knee are suddenly overstretched or overloaded, some or all of the muscle fibers can tear.
These are commonly referred to as muscle strains. Treated correctly, a full recovery is usually made in a few weeks, but if you try to return to strenuous activities too quickly, you are likely to suffer from long term problems
What is a Quads Strain Injury: Tear to some or all of the muscles fibers in one or more of the quadriceps muscles
Causes: Sports involving sprinting, jumping and kicking, muscle tightness, weakness and fatigue
Symptoms: thigh pain, swelling, bruising, "popping" sensation and difficulty walking, climbing stairs and getting in and out of a chair
Quads Injury Treatment: PRICE, exercises, tubigrip, physical therapy and occasionally surgery. Visit the Pulled Quads section to find out more.
What is a Quads Tendon Rupture: Full or partial tear of the quadriceps tendon that attaches the quadriceps muscles to the kneecap
Causes: Sports injuries, fall, twisting, tendon weakness, underlying medical condition, corticosteroids
Symptoms: immediate pain above kneecap often with audible "pop", limited knee extension, difficulty walking, knee swelling
Quads Tendon Rupture Treatment: Immobilisation, crutches, physical therapy or surgery for a complete tear. Visit the Quads Tendon Rupture section to find out more.
What is a Calf Strain Injury: Tear to some or all of the muscles fibres in one or both of the calf muscles
Causes: Suddenly - sudden acceleration e.g. jumping or sprinting, or gradually - repetitive overuse e.g. running
Calf Injury Treatment: PRICE, exercises, tubigrip, sometimes requires surgery. Visit the Calf Muscle Strain section to find out more.
Kneecap problems are less common knee injuries as they require a great deal of force through the knee. As a result, they tend to be more serious knee injuries.
What is a Knee Dislocation Injury: Knee cap get pushed out of place. This is one of the least common knee injuries
Causes: Usually caused by major, high impact injury e.g. car crash
Symptoms: Deformed leg - won’t be in a straight line. Very painful and swollen. Occasionally you lose feeling below the knee
Knee Dislocation Injury Treatment: Relocation of the bones, exercises, knee brace, may require surgery. Find out more in the dislocated patella section.
What is a Patella Fracture: When the kneecap bone breaks into two or more pieces.
Causes: A great force through the front of the knee e.g. falling from a height or impact from a car crash.
Symptoms: Pain and swelling at the front of the knee. Difficulty moving the knee and walking
Kneecap Fracture Treatment: May require surgery, exercises, knee brace and/or cast. Find out more in the kneecap injuries section
To find out more about each of the specific types of knee injury,
including simple and effective treatment options for each, choose from the
Common knee injuries are diagnosed by a combination of your history, physical examination and radiographic scans.
Doctors and physical therapist can diagnose many common knee injuries from what you tell them about how you injured your knee and your symptoms, and what they can see.
In some cases, they may also send you for tests such as an x-ray or MRI scan to look directly at the bone and/or soft tissues.
As well as these nine common knee injuries there are a number of other causes of knee pain which tend to come on gradually rather than suddenly, such as tendonitis and bursitis.
If you have a longer term knee condition or have been having knee pain for a while but don’t know what’s wrong, then go to the section devoted to common knee conditions.
Page Last Updated: 09/09/20
Next Review Due: 09/09/22
1. British Journal of Sports Medicine: Injuries around the knee - Symposium. Sancheti P, Razi M, Ramanathan EBS, et al. December 2010
2. Orthopedic Journal of Sports Medicine: A Nationwide Follow-up Survey on the Effectiveness of an Implemented Neuromuscular Training Program to Reduce Acute Knee Injuries in Soccer Players. Malin Åman M, Larsén K, Forssblad M, Näsmark A, Waldén M, Hägglund M. December 2018
3. Arthritis Research & Therapy Journal: Down on one knee: soft tissue knee injuries across the lifespan. Thorlund J, Culvenor A, Ratzlaff C. December 2014