If you’re experiencing lateral knee joint pain or pain on the outside of your knee when straightening it, you’re not alone. These symptoms are common and can stem from a range of conditions including iliotibial band syndrome, lateral meniscus injuries, or osteoarthritis. This post explores four key reasons behind outer knee pain, helping you understand what might be causing your discomfort and what typical treatment options look like. Whether your knee pain comes on during activity or lingers afterward, this guide offers valuable insights to help you move forward with more confidence and less pain. Let’s look at four common causes and what you can do about them.

IT Band Syndrome

Causes & Symptoms

This chronic injury is the bane of many runners, causing a sharp painful sensation where the iliotibial (IT) band inserts onto the outside of the shin bone. The repetitive motion of the fibrous IT band rubbing over other knee structures causes excessive friction leading to inflammation. Typically symptoms intensify over time particularly during periods of greater physical activity. The precise cause of the ITBS is currently unclear – bow leggedness, excessive foot supination, overtraining and weak hip muscles have been shown to contribute to the disorder, albeit not consistently.¹

Treatment

Standard treatment for ITBS consists primarily of strengthening and mobility exercises.³ Many therapists hypothesize that hip instability, characterized by Trendelburg’s Sign, places extra tension on the IT Band causing increased friction and pain on the outside of the knee.4 Isolated strengthening of the Hip External Rotators, Gluteus Maximus, Gluteus Medius and loosening the Tensor Fasciae Latae (TFL) may help decrease IT band tension thereby reducing symptoms.

Lateral Collateral Ligament (LCL) Sprain or Strain

Causes & Symptoms

The Lateral Collateral Ligament (LCL) connects the outside of your thigh bone to your fibula, a narrow long bone outside of your lower leg. The injury occurs when a large force presses on the inside of the knee, pushing the joint laterally outwards (bowing). The LCL resists against this pressure, however, if it is significant enough the fibers of the ligament begin to tear away resulting in pain and instability.

Treatment

An LCL strain can be suspected given pain on the outside of the knee after receiving a traumatic contact force to the inside of the knee. Your physician may order diagnostic imaging (MRI or X-ray) to assess the full extent of the damage. In cases of a complete tear, surgery may be required. Generally, symptoms resolve with rest and activity modification. However, depending on the severity, recovery times may vary – A grade 1 tear taking 2-3 weeks, and a grade 3 tear taking 3-6 months.

• Grade I: The LCL has been overstretched, while there is no major damage, its function will be compromised until it has healed.

• Grade II: The LCL has been partially torn and may require surgery to repair depending on the extent of the damage.

• Grade III: A complete tear of the LCL requiring surgery to reconstruct the ligament.

Ligaments don’t only act as “chains” connecting bones together, they also are extremely receptor-rich tissues. Embedded within fibers are small cells that sense changes in joint position (proprioception). When ligaments tear the sensitivity of these cells is also disrupted – less information about knee joint position reaches the brain. This can create joint instability, losses in balance, and diminish muscle reflexes. For these reasons, after the pain subsides, balancing exercises are often used to build the joint’s sense of position back up.

Tip from our bracing specialists

Lateral knee joint pain often arises from overuse or biomechanical imbalances that affect the outer structures of the knee. In many cases, using a knee brace can help redistribute load away from the painful area, especially during activities that involve repetitive bending and straightening. For those dealing with pain on the outside of the knee when straightening, supportive braces like those made by Spring Loaded may assist in reducing strain and improving stability. Addressing the underlying mechanics through targeted support can make everyday movement more comfortable.

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Lateral Meniscus Tear

Causes & Symptoms

The meniscus acts as your knee’s shock absorber, stopping bones from contacting one another directly. Sudden twisting or torsion related movements can cause fissures and tears to develop. Injuries to the lateral (outside) meniscus makeup 3.66% of serious knee injuries – much less than medial (inside) meniscus (10.76%).⁵ Other than pain, another common symptom of meniscal tears is a sudden loss in mobility. It can feel like there is pressure in your knee joint limiting your ability to fully bend and straighten it.

Treatment

Treatment varies depending on the type of tear, symptoms and activity level of the patient. For most, standard physiotherapy consisting of exercises, stretching and pain management works well. Where conservative rehabilitation fails, surgery may be needed in the form of a meniscectomy. During this procedure, damaged parts of the meniscus are cut out and completely removed. While this can provide tremendous relief in the short term, there are studies to suggest that meniscus removal increases the risk of arthritis later in life.⁶

Lateral Knee Arthritis

Causes & Symptoms

Arthritis disproportionally effects those over the age of 50⁸ The cartilage that normally protects the bony surfaces of your joints erodes away leaving painful bone on bone pressure. The result is an increase in internal joint friction eventually leading to the development of bone spurs. Symptoms include grinding sensations, stiffness and pain. There are four grades of knee arthritis (I-IV) which can be diagnosed using x-ray imaging.

Treatment

In lateral knee osteoarthritis, the damage is confined to the lateral side (outside) of your knee only, meaning that the medial and patellofemoral compartments on the inside of the knee and kneecap may still be quite healthy. There are many treatment options at your disposal. Pharmaceutical, exercise, diet, knee braces, injections, and surgery are all viable options. If you are suffering from severe knee arthritis, surgery may be considered a last resort – most doctors recommended exhausting your conservative treatment options first.⁹ For eligible patients, full knee replacement surgery can provide dramatically improve the quality of life and reduce painful symptoms. That being said, not everyone is happy with the final results from their surgery, the recovery is lengthy, and the procedure itself is extremely invasive.

Resources for Knee Pain on the Outside

Hopefully, this information has provided you with some insight as to what could be causing the pain on the outside of your knee. For more information on knee pain treatments visit our Complete Guide to Knee Pain

If knee arthritis is the underlying cause of your knee pain check out:

• • • Learn more about Osteoarthritis
    • Learn more about Osteoarthritis Treatment Option

Frequently Asked Questions (FAQ)

1. What causes lateral knee joint pain during activity?
Lateral knee joint pain during activity is commonly caused by conditions like iliotibial band syndrome or lateral meniscus tears. These issues often stem from repetitive motion, poor biomechanics, or degeneration in the outer knee compartment.

2. Why do I feel pain on the outside of my knee when straightening my leg?
Pain on the outside of the knee when straightening is typically linked to irritation or injury of the lateral structures of the knee, such as the iliotibial band or meniscus. These structures can become inflamed or compressed when the leg is extended.

3. Can a knee brace help relieve lateral knee joint pain?
Yes, a knee brace – especially one designed to offload pressure from the lateral compartment – can help manage lateral knee joint pain. These braces support alignment and reduce stress on painful areas during movement.

4.Is pain on the outside of the knee when straightening linked to arthritis?
Yes, osteoarthritis affecting the lateral compartment of the knee can lead to pain on the outside of the knee when straightening, particularly during weight-bearing activities or after prolonged periods of rest.

5.What are common treatments for lateral knee joint pain?
Common approaches to managing lateral knee joint pain include rest, ice, targeted strengthening exercises, and the use of supportive braces. Addressing the root cause through biomechanics or training adjustments is also helpful.