Understanding Pain on the Medial Side of the Knee

A sharp pain on the inside of your knee can start after a jog, a long walk, or even from sitting too long in an awkward position. The pain can make even the simplest movements feel challenging.

And while you might be tempted to shake it off and hope it gets better on its own, knowing what caused it can help you find the right solution faster. The medial side of your knee supports your weight, stabilizes your movement, and keeps you balanced when you walk, run, or climb stairs.

Consequently, it’s a spot that can easily become stressed or injured.  Knee pain can affect your day-to-day life and make it hard to focus at work, enjoy time with family, or even sleep comfortably. 

What the Inside of Your Knee Looks Like

From the knee's role in mobility, it’s easy to imagine it as a simple hinge that lets your leg bend and straighten. But the inside of your knee is made up of different parts that work together every time you move.

These components bear the load and keep you moving smoothly, even if you rarely give them a second thought.

1. The Cartilage

Cartilage is the soft, smooth tissue that lines the inside of your knee joint. It helps the bones move against each other without friction, like a cushion that absorbs shock every time you take a step.

This tissue can wear down over time or get damaged during sudden movements, leaving you with stiffness or pain.

2. The Meniscus

On the inside of your knee, the meniscus acts as an extra layer of cushioning. It’s a C-shaped piece of cartilage that spreads out the weight your knee handles every day.

This part of your knee is vulnerable to injuries from twisting or overuse, which might explain why you feel pain after certain activities.

3. The Ligaments

Ligaments are the sturdy bands of tissue that connect the bones in your knee. The medial collateral ligament (MCL), found on the inside, plays a big role in keeping your knee stable.

Injuries to this ligament can cause pain and make your knee feel less secure when you move.

4. The Tendons

Tendons connect the muscles in your thigh to the bones in your knee, helping you extend and bend your leg. These tissues can handle a lot of strain but are not immune to overuse or sudden injuries.

Pain in this area might come from inflammation or tiny tears in the tendon.

5. Synovial Fluid

Inside the joint, there’s a small amount of fluid that keeps everything moving smoothly. Synovial fluid reduces friction and nourishes the tissues inside your knee.

If this fluid gets inflamed or decreases, your knee can start to feel stiff or sore.

Common Causes of Pain on the Medial Side

Pain on the inside of your knee is often tied to how your knee moves, how much stress it endures, or even how you've been using it lately. The pain can stem from sudden injuries, gradual wear and tear, or certain medical conditions. 

1. Injuries from Twisting or Sudden Movements

Your knee is a highly mobile joint designed to bend, extend, and slightly rotate. However, its ability to twist has limits.

Sudden or forceful movements—like pivoting during sports, changing direction quickly, or tripping—can push your knee past its natural range of motion. This often results in injuries that range from mild strains to more severe ligament or cartilage damage like medial collateral ligament (MCL).

If you’ve ever felt a sharp pain in your knee after an awkward twist or sudden movement, you’re not alone. These injuries are common, especially during physical activities like running, soccer, or basketball.

2. Overuse from Repetitive Motion

Your knees are built to handle movement, but when the same motion is repeated too often without proper rest or variation, it can lead to overuse injuries. These occur when the stress placed on your knee joint exceeds its ability to recover.

Over time, repetitive activities can wear down the tissues in your knee, leading to pain, inflammation, and reduced mobility. Unlike acute injuries, which happen suddenly, overuse injuries develop gradually.

The pain may start as a mild annoyance, but if ignored, it can become debilitating. 

3. Osteoarthritis on the Medial Side

Osteoarthritis (OA) is a common condition that occurs when the cartilage protecting your joints wears down over time. When OA affects the medial side of your knee it’s often referred to as medial compartment osteoarthritis.

This type of arthritis can lead to pain, stiffness, and reduced mobility, making everyday activities like walking or climbing stairs more challenging. Because the medial side of the knee bears a significant portion of your weight during movement, it is particularly prone to wear and tear.

Medial OA can cause a noticeable bow-legged appearance as the inner joint space narrows, further altering how your knee handles stress.

4. Bursitis

Bursitis is a condition that occurs when a bursa, a small fluid-filled sac that cushions and reduces friction between bones, tendons, and muscles, becomes irritated or inflamed. Bursae are found throughout your body, including in the shoulders, hips, elbows, and knees.

When one of these bursa becomes inflamed, it can cause pain, swelling, and restricted movement. In the knee, bursitis commonly affects areas like the pes anserine bursa (on the inside of the knee) or the prepatellar bursa (in front of the kneecap).

While it may sound complex, bursitis is often tied to simple, everyday factors like repetitive movements, prolonged pressure, or minor injuries. 

5. Pes Anserine Tendinopathy 

Pes anserine tendinopathy, sometimes referred to as pes anserine bursitis, is a condition that affects the inside of your knee, just below the joint. It occurs where three tendons—coming from the hamstring muscles—attach to the shinbone (tibia).

These tendons form a structure resembling a goose’s foot, which is what “pes anserine” translates to. This area also contains a bursa, a small fluid-filled sac that reduces friction between the tendons and the bone.

When the tendons or the bursa become irritated or inflamed, it can result in pain, tenderness, and sometimes swelling on the medial side of the knee.

6. Alignment Issues or Biomechanical Problems

Your knees are designed to function within a specific alignment to support your body and absorb the forces generated during movement. When something disrupts that natural alignment it can lead to uneven wear and tear on the joints.

Over time, these alignment issues can result in pain, stiffness, or injuries, especially on the medial side of the knee. Biomechanical problems can alter how your entire lower body works, from your hips and pelvis to your ankles and feet.  

7. Acute Trauma or Direct Impact

Sometimes, knee pain occurs suddenly and unmistakably. Acute trauma or a direct impact on the knee is one of the most common causes of immediate pain and discomfort.

These injuries can affect the bones, cartilage, ligaments, tendons, or muscles around the knee. This can lead to a range of potential issues, from minor bruising to more serious damage.

If you’ve experienced a direct blow to your knee, your body’s natural response is to alert you with pain, swelling, or limited movement.

How to Know What’s Behind the Pain

Pinpointing the cause of medial knee pain becomes simpler if you know what to look for. Sometimes, it’s as simple as tracing the pain back to a specific activity or injury.

Other times, the signs are subtler, requiring a closer look at when the discomfort shows up and how it feels.

1. Listen to Your Pain

Your pain can tell you a lot about what’s happening. Sharp or stabbing pain that hits suddenly might point to an injury, like a meniscus tear or ligament strain.

On the other hand, a dull ache that worsens over time might indicate wear and tear, such as arthritis or tendon irritation. Pay attention to when the pain occurs.

Does it show up during or after exercise? Is it worse in the morning or after sitting for long periods? 

2. Check for Swelling or Stiffness

Swelling is often a sign of inflammation, which can result from injury, overuse, or conditions like bursitis. If your knee feels stiff or swollen, try to note how quickly it happened.

Sudden swelling might mean an acute injury, while gradual puffiness could point to something more chronic.

3. Notice Any Clicking or Instability

If your knee clicks, pops, or feels like it might give out, it could be a sign of a structural issue. A torn meniscus, for example, can cause a clicking sensation when you move.

Instability might indicate ligament damage, especially in the medial collateral ligament.

4. Look for Red Flags

Knee pain is common and often resolves with rest, ice, and care. However, some symptoms could point to a more serious issue that requires immediate medical attention.  

If your knee is visibly deformed, locks in place, or can’t bear weight, it’s a clear sign to seek medical attention. Pain that doesn’t go away, swelling that worsens, or difficulty moving your knee might be your body’s way of signaling that something isn’t right.

5. Test Your Range of Motion

Try bending and straightening your knee gently. Limited movement or pain during specific motions might help narrow down the cause.

Pain when squatting, for instance, could point to a meniscus issue, while discomfort during extension might involve the tendons or ligaments.

6. Don’t Ignore the Bigger Picture

Sometimes, knee pain isn’t just about the knee. Hip or ankle problems, poor posture, or even the way you walk can create stress on the medial side of your knee.

Issues like flat feet, tight hips, or an uneven gait can transfer stress to your knees. High-impact activities, lack of cross-training, or insufficient recovery time can wear down your knee over time.

Weak or overcompensating muscles around the joint can lead to instability and pain.

What You Can Do to Ease the Pain

There are simple steps you can take to ease the discomfort and support your knee’s healing. Small adjustments in how you rest, move, and manage pain can make a noticeable difference. 

1. Rest Without Completely Stopping Movement

Resting your knee is important, but that doesn’t mean you need to stop moving altogether. Avoid activities that make the pain worse, like running or jumping, but keep up with gentle movements like walking or stretching.

Staying active in a controlled way helps maintain circulation, which supports healing.

2. Use the RICE Method for Immediate Relief

The RICE method—rest, ice, compression, and elevation—can help reduce swelling and ease pain in the early stages. Apply ice for 15–20 minutes a few times a day, use a compression bandage to prevent swelling, and prop your knee up on a pillow to reduce pressure.

These simple steps can make a big difference, especially after an injury.

3. Stretch and Strengthen Safely

Tight muscles around your knee can pull on the joint and worsen pain. Gentle stretches for your hamstrings, quads, and calves can relieve tension and improve flexibility.

Once the pain subsides, strengthening exercises like leg lifts or seated knee extensions can help support the knee and prevent future pain.

4. Over-the-Counter Pain Relief

Non-prescription pain relievers like ibuprofen or acetaminophen can help reduce inflammation and ease discomfort. Always follow the recommended dosage, and use these medications as a short-term tool while you work on other ways to manage the pain.

5. Support Your Knee with Braces or Sleeves

A knee brace or compression sleeve can provide extra support and reduce strain on the medial side of your knee. These tools are especially helpful if you’re recovering from an injury or dealing with ongoing instability. 

Inner knee pain when running

Inner knee pain, especially when running, is something many people face, and it can quickly disrupt your rhythm and daily life. Pain on the medial side of the knee often signals something specific. 

Running places unique demands on your knees, particularly on the inside. The repeated impact, combined with your running form and the surfaces you run on, can take a toll.

If you've ever felt a twinge or persistent ache after a run, it's your knee's way of telling you something needs attention. Staying aware of how your body feels during and after a run can help protect your knees and help you recover if pain arises.