Common Knee Injuries

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Common knee injuries vary from minor falls which may settle down in a few days to major accidents which may take months to recover from. The knee ligaments and cartilage are the structures most commonly damaged.

Here you will find information on the most common knee injuries including how they occur, the knee injuries symptoms for each one and treatment information.

They are grouped into four categories:

1) Ligament Injuries: damage to the ligaments that support the joint
2) Cartilage Injuries: damage to the cartilage lining the joint
3) Muscle Injuries: damaged to the muscle fibres
4) Kneecap Injuries: damage to the patella bone

There are 4 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.

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.  They are the most common knee injuries in sports.

1) ACL Injuries

What is it: 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 Consequences: Lack of stability with pivoting and twisting
Treatment: Exercise rehab and/or surgery.

2) PCL Injury

What is it: 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
Long Term Consequences: Instability, particuarly with activities when the knee is bent e.g. stairs, problems with running
Treatment: Knee brace, physical therapy and/or surgery.

3) MCL tear

What is it: Damage to some or all of the fibres of the medial collateral ligament
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
Treatment: PRICE, exercises, knee brace.

4) Knee Sprain

What is it: Overstretching 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
Treatment: PRICE, exercises, knee braces.

The knee joint is lined with 2 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.

1) Meniscus Tear

What is it: Tear in the cartilage lining the knee joint. This is 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. arthritis
Symptoms: knee pain, swelling, locking, instability, difficulty straightening the knee, difficulty walking
Treatment: PRICE, exercises, knee brace, tubigrip, sometimes requires surgery. Can take a long time to heal.

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

1) Calf Strain

What is it: Tear to some or all of the muscles fibres in one or both of the calf muscle
Causes: a) Suddenly – sudden acceleration e.g. jumping or sprinting, or b) Gradually – repetitive overuse e.g. running
Symptoms: calf pain, swelling, bruising, difficulty walking, cramp
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.

1) Dislocated Patella

What is it: 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
Treatment: Relocation of the bones, exercises, knee brace, may require surgery.  Find out more in the kneecap injuries section

2) Patella Fracture

What is it: 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
Treatment: May require surgery, exercises, knee brace and/or cast.