Medial Knee Pain: 7 Possible Causes

What is medial knee pain?

Inner knee pain is a term that describes pain on the medial (inner) side of the knee. The knee can be easily injured as it is a complex joint found between the femur (thigh bone), tibia (leg bone) and patella (kneecap). There are many muscles, ligaments, and soft tissue that support the joint and can also be affected.

Inner knee pain is commonly caused by an injury, for example from a fall, sporting collision, or during a new activity.[1] Medial knee pain can also be caused by arthritis,[2] where there is a deterioration of the cartilage over time. The symptoms can include a sharp pain or a dull ache, stiffness, and occasionally swelling. In some cases, it can result in reduced range of motion of the knee and difficulty with everyday activities.[3]

Some causes of inner knee pain can present in a similar way to other causes. It is important to consult with a health practitioner if there are any concerns, particularly after an accident or trauma.

What are the symptoms of inner knee pain?

Common symptoms of inner knee pain include:

• A dull ache or sharp pain

• Stiffness

• Swelling

• Redness or heat

• Weakness

• Loss of stability

• Crepitus (clicking noises)

• Reduced range of motion

• Difficulty walking.

What causes inner knee pain?

Inner knee pain has many causes, including injuries, arthritis, and other conditions.

Some of the common causes of inner knee pain include:

1. Knee contusion

A knee contusion, commonly known as a bruise, can occur as a result of blunt trauma to the knee. This can be caused from incidents such as a direct collision in a sporting event, or from a fall or car accident.

Due to this force, the tissue and local blood vessels become damaged, resulting in a bruise. Other symptoms may include swelling, stiffness, and reduced movement in the knee. The colour of the bruise will likely change as healing progresses.

2. Osteoarthritis

Osteoarthritis (OA) is a type of arthritis where the bone cartilage degrades over time or as a result of an injury, which results in a narrowing of the joint space. It is more common in the older population.

Symptoms usually include a dull ache or sometimes a sharp pain, stiffness, and occasionally swelling. It may become increasingly painful to walk longer distances, go up and down stairs, or when moving from sitting to standing. If the OA is advanced and is impacting function or quality of life, surgery may be considered.

3. ACL injury

The anterior cruciate ligament (ACL) is one of the four major ligaments in the knee. It attaches between the femur and tibia, and it stabilises the knee by preventing unwanted movement in the knee. It is commonly injured in sporting situations, sometimes from a collision or at other times from moving awkwardly or landing a jump poorly.

An ACL injury is common in young and active populations, particularly during a pivoting or change-of-direction movement.[4] Injury to the ACL can result in a partial or full tear. An intense, sudden pain is usually experienced, alongside swelling, instability, and it is usually very difficult to put any weight through the affected knee. An ACL tear can be treated conservatively, or in some cases with surgery.

4. Medial meniscus injury

The medial meniscus is a moon-shaped structure in the knee. It has an important role as a shock absorber and guides the movement of the knee.

The meniscus is most commonly injured in high intensity activities when the knee is twisted and bent, for example during sports such as netball or soccer. However, the meniscus can also degrade or tear over time with age.

Symptoms of medial meniscus injury include medial knee pain, stiffness, and a locking or clicking sensation. Everyday activities such as squatting or kneeling can become difficult. The meniscus has a poor blood supply, so healing is difficult. In some cases, surgery may be necessary to address the injury.

5. MCL injury

The medial collateral ligament (MCL) is one of four major ligaments in the knee. It attaches between the medial side of the femur and tibia, and stabilises the knee by preventing any forces pushing the knee inwards.

When a force is applied to the outer knee, it can overstretch the MCL and cause a strain or tear. The symptoms are similar to an ACL injury.

The ACL, MCL, and meniscus are often injured together, referred to as the ‘unhappy triad’, as they have connections to each other in the knee.[5] Typically, this is during a sporting activity when a large force impacts the knee whilst the knee is bent or twisted and the foot is fixed on the ground. Surgery is often required in these situations.

6. Bursitis

Bursitis is a condition that occurs when the bursa, a small fluid-filled sac in the knee, becomes irritated or inflamed. A bursa is important as it absorbs load and reduces friction between different structures, such as tendons and bones.

There are several bursae in the knee. Medial knee pain may be caused by bursitis in the pes anserinus bursa, which reduces friction between the femur and the tendons of the three muscles that make up the pes anserinus: sartorius, gracilis, and semitendinosus.

7. Medial plica irritation

The medial plica is a membrane that spans between the patella and the knee joint, although the plica is not always present. Irritation can occur from overuse, commonly seen in sports with repetitive knee movements such as cycling, running, rowing, and team sports.

It is most problematic when the knee is bent between 40° to 80°, causing pain on impingement. The symptoms can present in a similar way to a medial meniscal tear.

Other causes of inner knee pain

• Fracture

• Baker’s cyst

• Tumour

• Patella (knee bone) subluxation or dislocation

• Osgood-Schlatter disease

• Infection

How is inner knee pain treated?

The treatment for medial knee pain depends on the cause and severity of the pain. In some cases, the pain will resolve on its own. However, in cases where the pain is severe or caused by an accident, it is important to get the correct diagnosis before any treatment starts.

Some common treatments may include:

Conservative treatment options

For minor medial knee pain, conservative (non-surgical) treatment options can be effective.

This may include:

• RICE principles: In the early stages of an injury, using the RICE principle (Rest, Ice, Compression, Elevation) can help reduce symptoms, such as pain or swelling.

• Activity modification: Avoiding the activity that caused the pain can help settle the pain and start the healing process.

• Pain relief medication: Over-the-counter medication can help settle the symptoms of inflammation and swelling. It is important to discuss this with a doctor if there are any concerns.

Medical treatment

In some cases, the pain may be severe or progressively worsen. It is important to consult a doctor, especially if the pain is from an accident or injury.

Medical treatment options may include:

• Assistance devices, such as a walking aid (crutches or frame) or a brace

• Prescription pain relief

• Corticosteroid injection

• Surgery.

When the pain is from an injury or accident, surgery may be the first line of treatment. For example, arthroscopic surgery may be required to repair a ligament or meniscal tear.

Physiotherapy for medial knee pain

Whilst it may not be possible to prevent all causes of inner knee pain, there are some strategies which can reduce the risk of injury. A physiotherapist can assess the knee and surrounding joints and structures to prescribe the most effective exercises.

A prescribed exercise program may include:

• Strength-based exercises, such as squats or leg press

• Aerobic exercise, including swimming or the stationary bike

• Balance exercises

• Stretching exercise, such as yoga or specific movements

• A walking or running program

Specific exercises that target the strength of the muscles in the legs can help strengthen the knee. Physiotherapy is particularly helpful after surgery, and the surgeon will likely recommend this to help restore function in the knee.

Things to consider about inner knee pain

There are a variety of causes of inner knee pain. As the knee is a complex structure, it can be injured easily, especially during contact sports. Improving and maintaining strength is one of the most effective ways to prevent inner knee pain.