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Knee pain affects about one in four adults, often limiting mobility and diminishing quality of life.
Pain on the outer (or lateral) part of the knee can be caused by an injury. It may also be the result of 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). Pain in this area may also be caused by arthritis.
Lateral knee pain is very common among distance runners. However, an injury that involves twisting the knee or one that pushes the knee out (away from the other leg) can also result in lateral knee pain.
Treatment for lateral knee pain depends on the cause and severity of your symptoms. Most of the time, conservative or nonsurgical treatment is all that’s needed. However, in some cases, surgery may be necessary. As with treatment, recovery time from a lateral knee injury depends on the severity of the problem.
In this article we explore some of the most common causes of lateral knee pain and how they’re diagnosed and treated.
Iliotibial band syndrome
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 usually affects runners. Athletes who engage in repetitive motions — such as cycling, climbing, and jumping — are also at higher risk.
Repetitively bending and straightening the knee under intense circumstances can cause it to tighten and become inflamed. The iliotibial band may also irritate nearby tissue. Pain is most commonly felt on the outer part of the knee but can be felt higher up in the outer thigh as well.
Lateral meniscus tear
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 — such as those who play football, soccer, tennis, and basketball — are especially vulnerable to this injury.
A torn lateral meniscus may also develop slowly as the cartilage becomes less resilient with age. These types of tears often occur without a noticeable injury but can cause significant pain. Other symptoms of meniscus tears include a locking sensation when attempting to straighten the leg, swelling, and pain when squatting.
Lateral collateral ligament injury
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 and can result in partial or complete tearing of the ligament.
Symptoms may include soreness on the outside of the knee, swelling, and stiffness. You may experience instability — 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.
With aging, the cartilage that helps cushion the ends of bones in the knee joint can wear thin and eventually allow the bones to rub together. Pain, stiffness, and 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 sided knee pain.
Lateral tibial plateau fracture
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 is often the result of a vehicle accident or a bad fall that impacts the outer knee directly.
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 the clinical term for a bruised knee. A 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 the bruise occurs on the outer knee, lateral knee pain can linger for a few hours or a few days, depending on the injury’s severity. Usually ice, rest, and elevating the knee are enough to relieve symptoms and allow the lateral knee bruise to heal.
How is knee pain on the outside of the knee diagnosed
When you see a doctor about lateral knee pain, they’ll first ask you to describe the location and type of pain, for example is the pain sharp or aching? They’ll also ask you when the pain started and what activity you were doing when your symptoms began.
They’ll then perform a physical examination that will typically involve extending and flexing your knee, as well as moving it gently from side to side. This may reveal whether there’s any swelling, areas of tenderness, or looseness in any of the ligaments.
Imaging tests may also be appropriate, including one or more of the following:
- X-ray to see bones
- Magnetic resonance imaging (MRI) to get detailed images of ligaments, tendons, muscles, and cartilage
- Computed tomography (CT) scan provides a more detailed image of the bone than is possible with a standard X-ray
Based on your symptoms, the physical exam and imaging, a doctor should be able to diagnose the cause and severity of your knee injury and propose a treatment plan.
How are these potential causes treated?
For minor lateral knee injuries, rest and conservative (nonsurgical) measures are all that are needed to allow them to heal. However, ligament tears, meniscus tears, and advanced arthritis may require surgery.
Iliotibial band syndrome
ITBS can usually be treated with rest and a slow return to activity once you’re feeling better. Exercises that improve flexibility of the iliotibial band and strength of the knee can also be helpful. Other treatments include:
- ice on the outside of the knee
- anti-inflammatory medications, such as ibuprofen (Advil), naproxen (Aleve) or acetaminophen (Tylenol)
- corticosteroid injection to reduce inflammation
A study published in the International Journal of Therapeutic Massage & Bodywork also found that a form of physical therapy known as soft tissue mobilization may also be effective at improving symptoms.
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 with some combination of rest, ice, bracing (or a compression bandage), physical therapy, and a “cortisone” injection.
More serious tears often require surgery to either repair the tear or trim off the damaged portion of meniscus tissue.
Sprains or minor tears of a ligament may not require surgery. Rest and bracing may be enough to allow the ligament to heal. A complete tear of the LCL most often requires an operation to repair.
The Osteoarthritis Research Society International recommends several non-surgical options for treating an arthritic 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 overweight) to help relieve pressure on the knees and other joints
For patients with advanced arthritis and severe pain, surgical options include partial or total knee replacement for those patients who have “failed” other forms of conservative (non-operative) treatment.
What’s the recovery like for these potential causes of knee pain?
Recovery time differs depending on the type of injury you have, how severe it is, and the physical therapy you’ve been prescribed. Here are the typical recovery times for specific injuries.
IT band syndromeLateral meniscus tearsLCL sprains or tearsOsteoarthritisFull ITBS recovery can take 4 to 8 weeks, depending on severity and how well you stick to physical therapy.A minor lateral meniscus tear may heal enough to allow you to return to normal activities within 2 weeks. With surgery, recovery time is about 6 weeks.Minor LCL sprains may take between a week to a month to heal enough for you to be able to return to normal activities. If surgery is required, full recovery may take several month for an LCL tear to heal.Nonsurgical treatments for osteoarthritis can start to help immediately. Surgery and physical therapy that follows can take several months to get you back to your usual activities.
With all major knee injuries, physical therapy is usually required to help you regain strength and full range of motion.
Knee injuries can affect athletes, children, older adults, and everyone in between. Because knee injuries can worsen without rest and proper treatment, it’s important to have lateral knee pain evaluated by a doctor. An orthopedic surgeon who specializes in knee injuries can be especially helpful in diagnosing and treating your injury.
If you’re a runner, remember that once you return to running, you should gradually build up the number of miles you run each week and try to run on an even, flat surfaces as much as possible. Uneven terrain and banked running tracks can lead to ITBS and other knee injuries.
Everyone should approach their recovery intelligently and follow the advice of healthcare professionals in order to avoid complications and to reduce the likelihood of a repeat injury.