Lateral knee pain is pain that occurs on the outer side of the knee. It is the least common place to experience pain and there are a variety of causes.
It may come on gradually over time or may develop suddenly after an injury. As a result, the symptoms are varied too. Pain may be a general ache or specific sharp pain and movement may be restricted.
Here you will find a summary of the most common causes of lateral knee pain. You can find out more about each condition including symptoms and treatment options for each by clicking on the relevant links.
Localised pain on the outer side of the knee will in most cases be due to one of the problems discussed here, but in some cases, the pain may actually be referred from somewhere else. 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.
What is it: Irritation of the thick fibrous band on the outer side of the knee known as the Iliotibial Band (ITB)
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 in the Iliotibial Band Syndrome section
What is it: Damage to some or all of the fibres of the Lateral Collateral Ligament on the outer side of the knee
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 in the Knee Sprain section
What is it: Tear in the cartilage lining on the outer side of the joint. It is the least common knee ligament to get injured
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 in the Meniscus Tear section
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:
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.
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.
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.
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.
To find out more about these common causes of lateral knee pain including symptoms, causes, diagnosis and treatment, use the links above.
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.