Medial Knee Pain: Causes, Symptoms, and Management

Why does my knee hurt on the inside?

Medial knee pain, or pain on the inside of the knee, typically stems from issues with structures supporting the inner aspect of the joint, such as ligaments, meniscus, bursa, or cartilage, often due to overuse, acute injury, or degenerative changes.

Understanding Medial Knee Anatomy

To comprehend why pain arises on the inside of your knee, it's crucial to understand the key anatomical structures in this region. The knee is a complex hinge joint, and its medial (inner) side is supported by several critical components:

• Medial Collateral Ligament (MCL): A strong, flat band of connective tissue running along the inner side of the knee, connecting the femur (thigh bone) to the tibia (shin bone). Its primary role is to resist valgus (knock-knee) stress and provide stability.
• Medial Meniscus: One of two C-shaped pieces of cartilage (menisci) located between the femur and tibia. The medial meniscus acts as a shock absorber and helps distribute weight evenly across the joint, protecting the articular cartilage.
• Pes Anserine Bursa: A small fluid-filled sac located on the inner side of the knee, approximately 2-3 inches below the joint line. It cushions the tendons of three muscles—the sartorius, gracilis, and semitendinosus (collectively known as the "pes anserine" tendons)—as they cross the tibia.
• Adductor Muscles and Tendons: Muscles on the inner thigh (e.g., adductor magnus, longus, brevis, gracilis) that attach near the knee can contribute to medial pain if strained or inflamed.
• Articular Cartilage: The smooth, slippery tissue covering the ends of the femur and tibia within the joint, allowing for frictionless movement. Damage to this cartilage, particularly in the medial compartment, can cause pain.

Common Causes of Medial Knee Pain

Most cases of medial knee pain can be attributed to a few prevalent conditions:

• Medial Collateral Ligament (MCL) Sprain:
  • Mechanism: Often occurs from a direct blow to the outside of the knee, forcing the knee inward (valgus stress), or from a sudden twisting motion.
  • Symptoms: Pain and tenderness directly over the MCL on the inner side of the knee, swelling, stiffness, and sometimes instability or a feeling of the knee "giving way." Pain typically worsens with side-to-side movements or when putting weight on the affected leg.
• Medial Meniscus Tear:
  • Mechanism: Can result from acute trauma (e.g., twisting the knee with the foot planted, common in sports) or degenerative changes over time, particularly in older individuals.
  • Symptoms: Sharp pain on the inside of the knee, especially with twisting, squatting, or kneeling. May include clicking, popping, or a sensation of the knee "locking" or catching. Swelling may develop gradually.
• Pes Anserine Bursitis:
  • Mechanism: Inflammation of the pes anserine bursa, often due to overuse, repetitive friction (e.g., running, cycling), tight hamstrings, obesity, or incorrect biomechanics.
  • Symptoms: Localized pain and tenderness on the inner side of the knee, a few inches below the joint line. Pain often worsens with activity, climbing stairs, or at night. Swelling is less common but can occur.
• Osteoarthritis (Medial Compartment):
  • Mechanism: Degenerative "wear and tear" of the articular cartilage, particularly affecting the medial compartment of the knee, leading to bone-on-bone friction. More common with age, obesity, previous injury, or genetic predisposition.
  • Symptoms: Gradual onset of pain that worsens with activity and improves with rest. Stiffness, especially in the morning or after periods of inactivity. Creaking or grinding sensations (crepitus). Swelling may be present.

Less Common, But Important, Causes

While less frequent, these conditions should also be considered, especially if common causes are ruled out:

• Adductor Tendinopathy/Strain:
  • Mechanism: Overuse or acute strain of the adductor muscles (inner thigh muscles) where their tendons attach near the knee. Common in athletes involved in kicking or quick directional changes.
  • Symptoms: Pain and tenderness along the inner thigh, radiating towards the knee, often worse with adduction (squeezing legs together) or stretching.
• Medial Plica Syndrome:
  • Mechanism: The plica is a fold in the synovial membrane (lining of the knee joint). If irritated or inflamed (e.g., by overuse or direct trauma), it can become thickened and catch between the bones, causing pain.
  • Symptoms: Dull ache on the medial side, sometimes with a snapping or popping sensation, especially when bending the knee. Can mimic meniscal tears.
• Referred Pain:
  • Mechanism: Pain originating from another area, such as the hip or lower back, can sometimes be felt on the inside of the knee.
  • Symptoms: Pain pattern may not directly correlate with knee movements, and other symptoms (e.g., hip stiffness, back pain, numbness/tingling) may be present.
• Stress Fractures:
  • Mechanism: Tiny cracks in the bone, often the medial tibia or femur, resulting from repetitive stress without adequate recovery. Common in runners or individuals with sudden increases in training load.
  • Symptoms: Localized bone tenderness, pain that worsens with weight-bearing and activity, and improves with rest.

Contributing Factors and Risk Considerations

Several factors can increase the likelihood of developing medial knee pain:

• Overuse and Training Errors: Rapid increases in training volume, intensity, or duration without adequate recovery.
• Improper Biomechanics:
  • Valgus Collapse: When the knee collapses inward during movements like squatting, running, or jumping, placing excessive stress on medial structures.
  • Excessive Foot Pronation: Flat feet or overpronation can alter the alignment of the lower kinetic chain, increasing strain on the medial knee.
• Muscle Imbalances: Weakness in hip abductors (gluteus medius), hip external rotators, or quadriceps, combined with tightness in hamstrings or adductors, can compromise knee stability and mechanics.
• Inadequate Warm-up and Cool-down: Insufficient preparation or recovery can leave tissues vulnerable to injury.
• Poor Footwear: Worn-out or unsupportive shoes can contribute to altered biomechanics and increased stress on the knee.
• Obesity: Increased body weight places greater load on the knee joints, accelerating wear and tear and increasing the risk of conditions like osteoarthritis and bursitis.

When to Seek Professional Medical Attention

While many cases of medial knee pain can be managed with initial self-care, it's crucial to consult a healthcare professional (e.g., physician, physical therapist, sports medicine specialist) if you experience:

• Severe pain that prevents you from bearing weight or performing daily activities.
• Significant swelling, bruising, or deformity around the knee.
• A popping or tearing sensation at the time of injury.
• Inability to bend or straighten the knee fully.
• Locking, catching, or giving way of the knee.
• Numbness, tingling, or weakness in the leg or foot.
• Fever or redness around the knee (could indicate infection).
• Pain that persists or worsens despite several days of rest and self-care.

Initial Self-Care and Management Strategies

For mild to moderate medial knee pain without severe symptoms, initial self-care can be beneficial:

• RICE Protocol (for acute injuries):
  • Rest: Avoid activities that aggravate the pain.
  • Ice: Apply ice packs to the affected area for 15-20 minutes, several times a day, especially in the first 24-48 hours.
  • Compression: Use an elastic bandage to reduce swelling (ensure it's not too tight).
  • Elevation: Elevate the leg above heart level to help reduce swelling.
• Activity Modification: Temporarily reduce or modify activities that trigger pain. Substitute high-impact exercises with low-impact alternatives (e.g., swimming, cycling).
• Over-the-Counter Pain Relievers: Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen can help manage pain and inflammation.
• Gentle Movement and Mobility: As pain allows, gently move the knee through its pain-free range of motion to prevent stiffness. Avoid movements that cause sharp pain.

Prevention Strategies

Proactive measures can significantly reduce the risk of medial knee pain:

• Progressive Overload: Gradually increase the intensity, duration, or volume of your workouts to allow your body to adapt. Avoid sudden spikes in training.
• Proper Form and Technique: Learn and maintain correct biomechanics for all exercises and sports-specific movements. Consider professional coaching or a movement analysis.
• Strength Training: Develop balanced strength in the muscles surrounding the knee, including quadriceps, hamstrings, glutes (especially hip abductors and external rotators), and core.
• Flexibility and Mobility: Incorporate regular stretching for hamstrings, quadriceps, hip flexors, and calf muscles. Address any identified muscle imbalances or tightness.
• Appropriate Footwear: Wear supportive shoes that are suitable for your activity and foot type. Replace worn-out shoes regularly.
• Listen to Your Body: Pay attention to early warning signs of pain or discomfort. Don't push through pain; modify or rest as needed.
• Maintain a Healthy Weight: Reducing excess body weight significantly decreases the load on your knee joints.

Understanding the potential causes and adopting preventive strategies are key to managing and avoiding medial knee pain, allowing you to maintain an active and healthy lifestyle.