Pain on the Outside of the Knee
Pain on the outside of the knee behaves quite differently depending on the cause. In runners and cyclists it is most often the iliotibial band, which typically hurts at a particular point in the stride and settles with rest. After a twist or a blow it is more likely to be the lateral meniscus or the ligaments on the outer side of the knee, and those deserve a closer look.
Also described as: lateral knee pain, pain outside the knee, ITB pain, outer knee pain running.
Go to A&E now if
- •A hot, very painful, swollen knee when you also feel unwell or feverish - this can be an infected joint and is treated as an emergency
- •A leg that is cold, pale, numb or that you cannot feel properly below the knee
- •An obvious deformity after an injury, or a knee that gives way completely and cannot take any weight at all
What causes it
Iliotibial band syndrome
An overuse problem in runners and cyclists. The pain builds predictably at a certain distance, is worse downhill, and is tender at a specific spot on the outer side of the knee rather than deep inside the joint.
More on sports knee injury clinicLateral meniscal tear
Deeper pain along the outer joint line, usually after a twist, and may catch or swell. Lateral tears behave differently from medial ones and the treatment decision is not the same.
More on meniscus repairPosterolateral corner or LCL injury
Injury to the ligaments on the outer side, causing pain and a sense of the knee opening outwards. Frequently missed, and an unrecognised injury here is a well-known reason ACL reconstructions fail later.
More on PLC reconstructionLateral compartment osteoarthritis
Wear confined to the outer half of the joint, sometimes in knees that are more knock-kneed in shape, where correcting alignment can be part of the answer.
More on distal femoral osteotomyWorth being seen within a week if
- •Outer knee pain after a significant twist or blow, particularly with swelling
- •A knee that feels like it opens outwards or gives way
- •Numbness, tingling or weakness lifting the foot after an injury to the outer knee
- •Running pain that has not settled despite reducing your mileage
How it is assessed
- •Distinguishing pain over the outer structures from pain deep in the joint, which separates an overuse problem from a structural tear.
- •Examination of the outer ligaments and of rotational stability.
- •Weight-bearing and long-leg alignment X-rays where the shape of the leg may be loading the outer side.
- •MRI where a meniscal or ligament injury is suspected.
Mr Sam Nahas is a consultant knee surgeon in Reading, and sees new knee problems within a week at Circle Reading Hospital. No GP referral is needed for self-pay patients.
Book a consultationThis page is general information about knee symptoms and does not replace individual medical advice. If you are worried about your knee, please be assessed.