Understanding Your Knee: An Orthopedic Guide

A simplified overview of common knee conditions treated in orthopedics.

Knee pain and discomfort can stem from various causes. In orthopedics, knee conditions are categorized to help diagnose and treat them effectively based on symptoms and origins. This guide provides an overview of the main types of knee problems you might encounter.

1. Degenerative Conditions (Wear-and-Tear or Age-Related Changes)

These conditions arise when the knee joint changes over time due to prolonged use or aging, leading to cartilage wear and bone deformation.

  • Osteoarthritis of the Knee

    This is the most common knee condition, where the knee cartilage wears down and the joint deforms, causing pain and restricted movement. In early stages, pain might be felt when climbing stairs or standing up, progressing to pain even at rest in advanced stages.

  • Degenerative Meniscus Tear

    The meniscus, which acts as a cushion in the knee, becomes more susceptible to damage with age-related changes, leading to tears from even minor impacts. Symptoms include pain, catching (a feeling of the knee locking), and sometimes locking (inability to move the knee).

  • Osteochondritis Dissecans

    Primarily seen in younger individuals, this condition involves a piece of cartilage and underlying bone detaching from the joint. It can cause pain during exercise and a catching sensation in the knee.

2. Traumatic Injuries (Due to Accidents or Sports)

These are knee injuries that occur from external forces, such as sports accidents or falls.

  • Ligament Injuries

    Ligaments (such as the anterior cruciate ligament, posterior cruciate ligament, medial collateral ligament, and lateral collateral ligament) that stabilize the knee joint can be partially or completely torn by external forces. These are common in athletes and can cause knee instability, swelling, and pain.

  • Acute Meniscus Tear

    A tear in the meniscus caused by sudden twists or impacts during sports. Characterized by pain during bending or straightening the knee, catching, and locking.

  • Fractures

    A break in the bones that form the knee joint, such as the distal femur, proximal tibia, or patella, due to strong external force. Symptoms include severe pain, swelling, and deformity.

  • Patellar Dislocation

    The kneecap (patella) moves out of its normal position. It causes severe pain and visible deformity, and often tends to recur once it has dislocated.

3. Inflammatory Conditions (Pain and Swelling due to Inflammation)

These conditions involve inflammation in or around the knee joint due to infection, autoimmune reactions, or overuse.

  • Rheumatoid Arthritis

    An autoimmune disease where the immune system attacks joints throughout the body, including the knee. Characterized by morning stiffness, pain, swelling, and deformity.

  • Gout

    Caused by high levels of uric acid in the blood, leading to the formation of uric acid crystals in joints, causing sudden and severe inflammation and pain. Can affect the knee joint.

  • Pseudogout

    An inflammatory condition caused by calcium pyrophosphate crystal deposition in the joints, similar to gout but with normal uric acid levels.

  • Bursitis

    Inflammation of a bursa (fluid-filled sacs that reduce friction in joints) around the knee joint, causing pain and swelling.

  • Patellar Tendinitis / Jumper's Knee

    Inflammation of the patellar tendon below the kneecap, common in athletes who perform many jumping movements. Pain is concentrated below the kneecap.

  • Pes Anserine Bursitis / Tendinitis

    Inflammation at the attachment point of the pes anserine tendons on the inside of the knee, often seen in runners and those who overuse their knees.

4. Other Conditions

These are conditions caused by specific factors or states not categorized above.

  • Symptomatic Bipartite Patella

    A condition where the kneecap is not fully fused into one bone but remains in two or more separate pieces, causing pain, especially during exercise.

  • Baker's Cyst (Popliteal Cyst)

    A fluid-filled sac that forms behind the knee. It may not cause pain but can lead to a feeling of pressure or discomfort if it grows large.

Disclaimer: This information is for educational purposes only and should not be considered medical advice. If you experience knee pain or discomfort, please consult a specialized orthopedic doctor for proper diagnosis and treatment. Do not self-diagnose or self-treat.