Knee Pain: Understanding Its Medical Term and Underlying Causes

What is knee pain called?

Knee pain itself is a symptom, not a specific medical condition name. While the formal medical term for pain in the knee joint is gonalgia, this term is rarely used in common parlance. Instead, knee pain is typically named by its underlying cause or the specific anatomical structure affected.

Gonalgia: The Medical Term for Knee Pain

While the query "What is knee pain called?" might suggest a single, overarching term, the reality in clinical practice is more nuanced. The medically accurate term for knee pain is gonalgia. This term, derived from "gon" (meaning knee) and "algia" (meaning pain), serves as a precise descriptor for the symptom of pain localized to the knee joint.

However, it's crucial to understand that gonalgia is a symptom, not a diagnosis. A healthcare professional will rarely diagnose a patient with "gonalgia." Instead, gonalgia is the patient's chief complaint, which then prompts a thorough investigation to identify the specific underlying condition causing the pain. Therefore, when discussing knee pain, clinicians and patients alike typically refer to the specific disease, injury, or syndrome that is responsible for the discomfort.

Common Categories of Knee Pain Conditions

Knee pain can stem from a vast array of issues, ranging from acute injuries to chronic degenerative conditions. Understanding these categories is key to comprehending the diverse "names" associated with knee pain.

Acute Injuries

Acute knee pain often results from a sudden trauma or specific incident.

• Ligament Sprains or Tears:
  • ACL Tear (Anterior Cruciate Ligament Tear): Often characterized by a "pop" sound, instability, and swelling.
  • MCL Tear (Medial Collateral Ligament Tear): Pain and tenderness on the inside of the knee, often due to a valgus (outward) force.
  • LCL Tear (Lateral Collateral Ligament Tear): Less common than MCL, pain on the outside of the knee, often due to a varus (inward) force.
  • PCL Tear (Posterior Cruciate Ligament Tear): Often caused by direct impact to the front of the shin, leading to posterior instability.
• Meniscus Tears: Tears in the C-shaped cartilage pads that cushion the knee joint.
  • Medial Meniscus Tear: More common, pain on the inside of the knee, often with twisting injuries.
  • Lateral Meniscus Tear: Pain on the outside of the knee.
  • Symptoms can include locking, catching, swelling, and pain with twisting.
• Fractures: Breaks in the bones around the knee.
  • Patellar Fracture: Break in the kneecap.
  • Tibial Plateau Fracture: Break in the top part of the shin bone.
  • Distal Femur Fracture: Break in the lower part of the thigh bone.
• Tendinitis/Tendinopathy: Inflammation or degeneration of tendons.
  • Patellar Tendinitis (Jumper's Knee): Pain below the kneecap, common in athletes involving jumping.
  • Quadriceps Tendinopathy: Pain above the kneecap.
• Bursitis: Inflammation of the fluid-filled sacs (bursae) that cushion the joint.
  • Prepatellar Bursitis (Housemaid's Knee): Swelling and pain over the front of the kneecap.
  • Pes Anserine Bursitis: Pain on the inner side of the knee, below the joint line.
• Dislocation:
  • Patellar Dislocation: The kneecap slips out of its groove.
  • Knee Joint Dislocation: A severe injury where the tibia and femur lose alignment, often involving multiple ligament tears.

Chronic Conditions and Overuse Injuries

These conditions develop gradually over time, often due to repetitive stress, degenerative changes, or underlying systemic issues.

• Osteoarthritis (OA): The most common form of arthritis, characterized by the breakdown of joint cartilage, leading to pain, stiffness, and reduced mobility. Often referred to as "wear-and-tear" arthritis.
• Patellofemoral Pain Syndrome (PFPS): Often called Runner's Knee or Chondromalacia Patellae (though the latter specifically refers to cartilage softening). Characterized by pain around or behind the kneecap, especially with activities like running, squatting, or going up/down stairs.
• Iliotibial Band Syndrome (ITBS): Another common cause of Runner's Knee, characterized by pain on the outer side of the knee, where the IT band rubs over the lateral femoral epicondyle.
• Osgood-Schlatter Disease: A common cause of knee pain in adolescents, characterized by inflammation of the patellar tendon where it attaches to the shinbone, causing a painful bump below the kneecap.
• Baker's Cyst (Popliteal Cyst): A fluid-filled sac that forms at the back of the knee, often associated with other knee conditions like arthritis or meniscus tears.
• Rheumatoid Arthritis (RA) & Other Inflammatory Arthritides: Systemic autoimmune diseases that can cause chronic inflammation and pain in the knee joint, often affecting multiple joints symmetrically.
• Gout/Pseudogout: Forms of inflammatory arthritis caused by crystal deposition in the joint, leading to sudden, severe pain, swelling, and redness.

Referred Pain

Sometimes, knee pain isn't originating from the knee itself but is "referred" from another part of the body. Conditions in the hip (e.g., hip osteoarthritis, hip labral tears) or lower back (e.g., sciatica, lumbar radiculopathy) can manifest as pain in the knee. This highlights the importance of a comprehensive assessment when diagnosing knee pain.

Diagnosing the Cause of Knee Pain

Given the multitude of potential causes, accurately diagnosing the specific condition behind knee pain is paramount for effective treatment. This typically involves:

• Medical History and Physical Examination: A detailed account of symptoms, injury mechanism, and a thorough physical assessment of knee range of motion, stability, tenderness, and special tests.
• Imaging Studies:
  • X-rays: To assess bone structure, fractures, and signs of arthritis.
  • MRI (Magnetic Resonance Imaging): Provides detailed images of soft tissues like ligaments, tendons, cartilage, and menisci.
  • CT Scan (Computed Tomography): Useful for detailed bone imaging, especially in complex fractures.
  • Ultrasound: Can visualize tendons, ligaments, and fluid collections.
• Laboratory Tests: Blood tests may be ordered to rule out inflammatory conditions (like rheumatoid arthritis) or infections.

When to Seek Medical Attention

While mild knee pain may resolve with rest and conservative measures, it's important to seek medical attention if you experience:

• Severe pain or swelling.
• Inability to bear weight on the affected leg.
• Noticeable deformity of the knee.
• Inability to fully extend or bend the knee.
• A "popping" sound at the time of injury.
• Redness or warmth around the joint, especially with fever.
• Symptoms of locking, catching, or giving way.

Conclusion

In summary, while gonalgia is the formal medical term for knee pain, the experience of knee pain is almost always identified and treated based on its underlying cause. From acute injuries like ACL tears and meniscus tears to chronic conditions such as osteoarthritis and patellofemoral pain syndrome, each specific diagnosis carries its own name and requires a targeted approach to management. Understanding that knee pain is a symptom, and not a diagnosis in itself, is the first step toward effective treatment and recovery.