Knee Pain – Causes, Symptoms and Treatment

What Is Knee Pain?

Knee pain is among the most frequently reported musculoskeletal complaints worldwide. The knee is the largest joint in the human body and is subject to significant mechanical stress throughout daily life. Knee pain can arise suddenly following an injury or develop gradually due to chronic conditions. It may be felt at the front, back, inner, or outer side of the knee and can range from mild discomfort to severe, debilitating pain.

Causes of Knee Pain

Knee pain has a wide range of potential causes, broadly categorized as acute (sudden onset) or chronic (long-term).

Acute Causes

• Ligament injuries: Tears or sprains of the anterior cruciate ligament (ACL) or other knee ligaments are common in sports.
• Meniscus tear: The menisci are cartilage discs acting as shock absorbers; they can tear during twisting movements.
• Patellar dislocation: The kneecap (patella) slips out of its normal position, causing sudden pain.
• Contusions and bruising: Direct impact to the knee can cause significant pain and swelling.
• Bursitis: Inflammation of the bursae (small fluid-filled sacs) surrounding the knee joint.

Chronic Causes

• Knee osteoarthritis (gonarthrosis): Gradual breakdown of joint cartilage, most common in older adults.
• Rheumatoid arthritis: An autoimmune condition in which the immune system attacks the joint lining.
• Patellar tendinopathy (jumper's knee): Overuse injury of the patellar tendon, prevalent among athletes.
• Iliotibial band syndrome: Lateral knee pain caused by friction of the iliotibial band, common in runners.
• Osgood-Schlatter disease: Growth-related knee pain occurring primarily in adolescents.

Symptoms

The symptoms associated with knee pain vary depending on the underlying cause. Common accompanying signs include:

• Swelling or warmth around the knee
• Stiffness or reduced range of motion
• Clicking, popping, or grinding sensations
• A feeling of instability or the knee giving way
• Pain when climbing stairs, running, or sitting for extended periods
• Redness of the skin over the knee joint

Diagnosis

Diagnosing knee pain begins with a thorough medical history and physical examination. The physician will assess the location, onset, and nature of the pain. Common diagnostic tools include:

• X-ray: Evaluates bone structure, joint space narrowing, and signs of arthritis.
• MRI (Magnetic Resonance Imaging): Provides detailed images of soft tissues including ligaments, menisci, and cartilage.
• Ultrasound: Useful for assessing tendons, bursae, and fluid accumulation.
• Blood tests: Ordered when inflammatory or autoimmune conditions such as rheumatoid arthritis are suspected.
• Arthroscopy: A minimally invasive procedure allowing direct visualization of the inside of the knee joint.

Treatment

Treatment of knee pain depends on the underlying cause and severity. A variety of options are available:

Conservative Treatment

• Rest and ice application: Particularly important for acute injuries (RICE principle: Rest, Ice, Compression, Elevation).
• Pain-relieving medications: Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or diclofenac help reduce pain and inflammation.
• Physiotherapy: Targeted strengthening and stretching exercises to stabilize the knee joint.
• Braces and supports: Orthotic devices can provide additional support and offload the joint.
• Corticosteroid injections: Injections directly into the joint to reduce severe inflammation.
• Hyaluronic acid injections: Used in osteoarthritis to improve joint lubrication and reduce friction.

Surgical Treatment

• Arthroscopy: Minimally invasive surgery to repair or remove damaged meniscal tissue or reconstruct ligaments.
• Knee replacement (arthroplasty): In advanced osteoarthritis, the joint may be partially or fully replaced with a prosthesis.
• ACL reconstruction: Surgical restoration of a torn anterior cruciate ligament using a tendon graft.

Prevention

Many causes of knee pain can be prevented or their progression slowed through proactive measures:

• Adequate warm-up before physical activity
• Strengthening the muscles surrounding the knee (quadriceps, hamstrings, and calves)
• Maintaining a healthy body weight to reduce stress on the joint
• Wearing appropriate, supportive footwear
• Avoiding overtraining and repetitive high-impact activities without adequate recovery

When to See a Doctor

Medical attention should be sought promptly if any of the following occur:

• Significant swelling, redness, or warmth in the knee
• Severe pain following an accident or fall
• A sensation of the knee locking or giving way
• Pain that does not improve with rest and self-care
• Fever combined with knee pain, which may indicate a joint infection

References

1. National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS): Knee Problems. Available at: https://www.niams.nih.gov/health-topics/knee-problems (2023).
2. World Health Organization (WHO): Musculoskeletal conditions. Available at: https://www.who.int/news-room/fact-sheets/detail/musculoskeletal-conditions (2023).
3. Brukner P., Khan K.: Clinical Sports Medicine, 5th edition. McGraw-Hill Education, 2017.