An injury, inflammation, or arthritis most likely cause pain outside the knee. A doctor can determine the cause based on your other symptoms and the results of imaging tests.

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Pain on the outer (or lateral) part of the knee can happen due to an injury or arthritis. It may also result from inflammation in a band of tough fibrous tissue that runs down the outside of the thigh and attaches to the front of the tibia (shin bone).

Lateral knee pain is common among distance runners. However, injuries that involve twisting the knee or pushing the knee away from the other leg can also cause lateral knee pain.

Knee pain can often limit your mobility and reduce your quality of life.

Treatment and recovery time depends on the cause and severity of your symptoms. Often, doctors recommend conservative or nonsurgical treatment. But, in some cases, surgery may be necessary.

This article explores common causes of lateral knee pain and how they’re diagnosed and treated.

The iliotibial band is a thick strip of connective tissue that runs from the outer hip down to the shinbone. Research suggests that iliotibial band syndrome (ITBS) is more common among males than females and often affects runners. Athletes who engage in repetitive motions — such as cycling, climbing, and jumping — also have a higher risk.

Repetitive bending and straightening the knee under intense circumstances can cause it to tighten and become inflamed. The iliotibial band may also irritate nearby tissue. This injury typically causes pain on the outer part of the knee, but people may feel it on the outer thigh as well.

The menisci are two tough, rubbery pieces of cartilage that sit in between the femur (thigh bone) and tibia (shinbone). The medial meniscus is on the inside part of the knee, while the lateral meniscus is on the outer side.

The lateral meniscus is often torn during a sudden twisting motion when the foot is planted, and the body turns to the side. Athletes who make sudden change-of-direction moves are especially vulnerable to this injury. This can include people who play:

  • football
  • soccer
  • tennis
  • basketball

A torn lateral meniscus may also develop slowly as the cartilage becomes less resilient with age. These tears can occur without a noticeable injury but cause significant pain. Other symptoms of meniscus tears include:

The lateral collateral ligament (LCL) is one of the four main ligaments of the knee. It connects the outer side of the femur and tibia and is primarily responsible for stabilizing the outer aspect of the knee.

An LCL injury (sprain) is often the result of a blow to the inside part of the knee; this causes the LCL to stretch beyond normal range of motion and can result in partial or complete tearing of the ligament.

Symptoms may include:

  • soreness on the outside of the knee
  • swelling
  • stiffness
  • instability, or a feeling that the knee is unstable and going to buckle or give out

Osteoarthritis (OA) is the most common form of arthritis and affects more than 32 million adults in the United States.

As you age, the cartilage that helps cushion the ends of bones in the knee joint can wear thin and eventually allow the bones to rub together. With osteoarthritis of the knee, you may experience:

  • pain
  • stiffness
  • loss of joint movement can follow

Some people have more significant wearing of the cartilage in the outer compartment of the knee joint, and this can lead to lateral knee pain. This can include people with a bowed leg.

The tibial plateau is located at the top of the shin at the knee. A break on the outer or lateral part of the tibial plateau can cause considerable knee pain. A lateral tibial plateau fracture often results from a vehicle accident or a bad fall directly impacting the outer knee.

If the bones are still aligned, surgery may not be required to treat the injury. If not, you may need surgery to place the affected bones in their proper position and secure them with screws or plates.

A knee contusion is a clinical term for a bruised knee. Soft-tissue contusion is limited to the skin and muscle tissue, but if the injury is deep enough to hurt the bone, it’s called a bone contusion.

When a bruise occurs on the outer knee, lateral knee pain can linger for a few hours or days, depending on the injury’s severity. Usually, ice, rest, elevating the knee, and gentle stretching can relieve symptoms and allow the lateral knee to heal.

When you see a doctor about lateral knee pain, they’ll typically ask you to describe the location and type of pain, whether sharp or achy. They may ask about when the pain started and the activity you were doing when your symptoms began.

A physical examination typically involves extending and flexing your knee and evaluating your knee stability, as well as moving it gently from side to side. This may reveal whether there’s any swelling, pain, areas of tenderness, or looseness in any of the ligaments.

Imaging tests may also be appropriate, including one or more of the following:

Based on your symptoms, physical exam, and imaging results, a doctor can diagnose the cause and severity of your knee injury and recommend treatment.

For minor lateral knee injuries, rest and conservative (nonsurgical) measures are all that is needed to allow them to heal. However, ligament tears, meniscus tears, and advanced arthritis may require surgery.

Iliotibial band syndrome

For ITBS, a doctor may recommend rest and a slow return to activity once you feel better. IT band exercises and stretches may improve iliotibial band flexibility and knee strength. Other treatments include:

Lateral meniscus tear

Only the very outer portion of the meniscus has a healthy blood supply, and therefore most meniscus tears do not heal on their own. However, small tears can be treated without surgery through some combination of:

More serious tears often require surgery to either repair the tear or trim off the damaged portion of meniscus tissue.

Ligament injuries

Sprains or minor tears of a ligament may not require surgery. Rest and bracing may allow the ligament to heal. A complete tear of the LCL often requires an operation to repair.

Osteoarthritis

The Osteoarthritis Research Society International recommends several nonsurgical options for treating arthritis of the knee. These include:

  • strength training to help the muscles surrounding the knee better support and stabilize the joint
  • biomechanical devices, such as knee braces, to support the knee when walking and doing other activities
  • water- and land-based exercises to help improve knee flexibility and function
  • weight loss, if indicated, to relieve pressure on the knees and other joints
  • injections, including steroids or hyaluronic acid
  • low impact exercises, such as using a stationary bike

For people with advanced arthritis and severe pain, surgical options include partial or total knee replacement if they have not had success with other forms of treatment.

Recovery time differs depending on the type of injury, its severity, and the physical therapy you’ve been prescribed. The typical recovery times before you can return to typical activities include:

IT band syndromeLateral meniscus tearsLCL sprains or tearsOsteoarthritis
4 to 8 weeks, depending on severity and how well you stick to physical therapytypically within 2 weeks for a minor tear, and 6 weeks for a major tear with surgerya week to a month for minor injuries, and several months if surgery is requirednonsurgical treatments can help immediately, but if you need surgery and physical therapy, recovery can take several months

With all major knee injuries, physical therapy is usually all you need to help you regain strength and full range of motion.

Knee injuries can affect athletes and people of all ages. Because knee injuries can worsen without rest and proper treatment, doctors recommend having lateral knee pain evaluated. An orthopedic surgeon specializing in knee injuries can help diagnose and treat your injury.

If you’re a runner, once you return to running, you should gradually build up the miles you run each week and try to run on even, flat surfaces as much as possible. Uneven terrain and banked running tracks can lead to ITBS and other knee injuries.

Following the advice of healthcare professionals can help you avoid complications and to reduce the likelihood of a repeat injury.