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 are:
1) Ligament Injuries: damage to the ligaments that support the joint
2) Muscle Injuries: damaged to the muscle fibres
3) Kneecap Injuries: damage to the patella bone
4) Cartilage Injuries: damage to the cartilage lining the joint
The knee ligaments and cartilage are the structures most commonly damaged.
Knee injury diagnosis involves looking at the cause of your knee injury and the symptoms you are experiencing. The most common symptoms of knee injuries are pain and swelling, but there may also be other symptoms such as instability, locking, clicking and giving way.
Knee injuries can be diagnosed by both history and physical examination. Often, your doctor will be able to diagnose a knee injury from what you tell them and what they can see, but in some cases, they may also send you for tests such as an x-ray or MRI scan.
Here, we look at the 8 most common knee injuries: including how they occur, the symptoms for each one and the best knee injury treatment options.
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/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
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
MCL Knee Injury Treatment: PRICE, exercises, knee brace. See the
section for more info.
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. See 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: a) Suddenly - force through the knee or sudden twisting of the knee, or b) 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, some or all of the muscle fibres can tear.
These are commonly referred to as muscle strains. Treated correctly, and a full recovery is usually made in a few weeks, but if you try to return to activity too quickly, you are likely to suffer from long term problems
What is a Calf Strain Injury: Tear to some or all of the muscles fibres in one or both of the calf muscles
Causes: a) Suddenly - sudden acceleration e.g. jumping or sprinting, or b) 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.
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
As well as common knee injuries there are a number of other causes of knee pain which tend to come on gradually rather than suddenly.
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 my section devoted to common knee conditions or visit the knee pain diagnosis section for help working out what is causing your knee pain.
You can also find a wide range of treatment options in the knee pain treatment section.
Page Last Updated: 25/04/19
Next Review Due: 25/04/21
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