Lateral Knee Pain

Written By: Chloe Wilson, BSc(Hons) Physiotherapy
Reviewed by: KPE Medical Review Board

Find out about the most common causes of lateral knee pain

Lateral knee pain is pain that occurs on the outside of the knee.  It may come on gradually over time or may develop suddenly after an injury. As a result, the symptoms are varied too.

Outer knee pain may be a general ache or specific sharp pain and movement may be restricted.

Here, we look at the most common causes of lateral knee pain, what causes them, the typical symptoms and how to treat them.

The outer side of the knee is the least common place to experience knee pain. In most cases, localised pain on the outer side of the knee is due to an injury affecting one of the structures on the outer side of the knee. However, in some instances, the pain may actually be referred from somewhere else, typically the lower back or the hip. 

If none of these sound quite like your problem, visit the knee pain diagnosis section for more help working out what is causing your pain.

Common Causes of Lateral Knee Pain

1) Iliotibial Band Syndrome

What is it: Irritation of the thick fibrous band on the outer side of the knee known as the Iliotibial Band (ITB)

Lateral knee pain occurs on the outer side of the knee

Symptoms: Outer knee pain mainly when the heel strikes the floor, inflammation

Causes: Muscle tightness and weakness, running (esp long distance or on sloped surface), flat feet, sudden increase in activity

Aggravating Activities: Running (especially long distance), stairs, cycling, hiking, weight lifting, squats

Onset: Develops gradually with overuse

Treatment: Rest from aggravating activities, exercises, knee strap, orthotics, steroid injection

Find out more: Iliotibial Band Syndrome

2) Lateral Collateral Ligament Sprain

What is it: Damage to some or all of the fibres of the Lateral Collateral Ligament on the outer side of the knee

A sprain/tear of the lateral collateral ligament is a common cause of pain on the outer side of the knee aka lateral knee pain

Symptoms: Outer knee pain, swelling, bruising, instability, stiffness

Causes: A blow to the inside or the knee, sudden twisting or a fall where the lower leg is forced inwards

Aggravating Activities: Bending the leg, walking, stairs, sports

Onset: Sudden onset 

Treatment: PRICE, exercises, knee brace

Find out more: Knee Sprains

3) Lateral Meniscus Tear

What is it: A tear in the cartilage lining on the outer side of the joint. It is the least common knee ligament to get injured

A tear in the meniscus can cause lateral knee pain

Symptoms: Lateral knee pain, swelling, locking, instability, difficulty straightening the knee

Causes: Sudden knee twisting on a bent knee and planted foot or wear and tear

Aggravating Activities: Walking, running, squatting, stairs especially going up

Onset: Can be sudden (injury) or gradual (wear and tear)

Treatment: PRICE, exercises, knee brace, surgery

Find out more: Meniscus Tears

Other Possible Causes

We have looked at the three most common causes of lateral knee pain, but if none of these are sounding like your problem, it could be one of the following:

1) Arthritis

Arthritis in the lateral part of the knee (the outer side) causes outer knee pain

Wear and tear and inflammation in the joint can cause lateral knee pain.  Arthritis typically affects the medial (inner) side of the knee more than the lateral side, but this is not always the case.  

The classic symptoms of knee arthritis are a dull, nagging achy pain in the knee, stiffness (particularly in the morning) and creaky/noisy knees.  It typically affects people over the age of 50. Find out everything you need to know in the knee arthritis section.

2) Nerve Problems

Pressure along the path of the peroneal nerve can also cause outer knee pain. The peroneal nerve branches off from the sciatic nerve and runs down the outer side of the lower leg to the foot. Nerve pain is often associated with tingling, pins and needles and or numbness.  

Damage to the peroneal nerve usually occurs when there is a blow to the side of the knee, which squashes the nerve where it sits just below the skin. Alternatively, there may be pressure higher up the nerve where the sciatic nerve branches off from the lower part of the lumbar spine e.g. from a disc protrusion.

The pain can refer (travel) down the nerve and may result in lateral knee pain, with or without associated back pain. Again, there will often be neurological symptoms as well such as tingling and/or numbness. 

3) Hamstring Tendonopathy

Biceps Femoris tendinopathy causes lateral knee pain

Inflammation or degeneration of the biceps femoris tendon (one of the hamstring muscles), where it attaches to the outer side of the back of the knee, can also cause lateral knee pain.

The area will be tender to touch and pain will get worse with resisted knee flexion. There may also be pain and stiffness in the knee after exercise.

It usually affects people who play sports where there is a lot of acceleration and deceleration work.

4) Proximal Tibiofibular Joint Dislocation

This is one of the most unusual causes of lateral knee pain. It affects the joint between the top of the shin bone (tibia) and the fibular, the small, thin bone that runs down the outer side of the shin, just below the knee joint on the outer side.

It takes a large force to dislocate the joint, e.g. a car accident, but it can also partially dislocate (sublux) usually due to a fall when the foot  is plantarflexed (toes pointing down), which often also damages the tibiofibular ligament.

Symptoms usually include lateral knee pain, instability especially during deep squats and sometimes an obvious deformity at the side of the knee. There may also be associated damage to the peroneal nerve leading to pins and needles or numbness around the outer knee. 

What Next?

If you would like some help working out what is causing your pain using other specific symptoms, how the pain started or the specific location of the pain, visit the knee pain diagnosis section and learn what you can do about it. Remember, any new incidence of pain should always be assessed by your doctor.

To find out more about these common causes of lateral knee pain including symptoms, causes, diagnosis and treatment, use the links above. 

  1. Knee Pain Guide
  2.  ›
  3. Diagnosis
  4.  ›
  5. Lateral Knee Pain

Page Last Updated: 14/9/18
Next Review Due: 14/9/20

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