There are three separate areas in the knee: the medial compartment, the lateral compartment and the kneecap joint or patella-femoral compartment. The knee joint is considered a hinge joint, where it flexes and extends in one plane. However, there are also minor rotational and gliding forces that are involved in normal knee movement. The knee is a structurally shallow joint, unlike the hip, therefore it relies on soft tissue structures for stability. The structures of the knee, other than the femur (thigh bone), tibia (shin bone) and the patella (knee cap) are the ligaments and cartilage that give the knee its stability.


The medial and lateral compartments are the weight bearing areas of the knee. They are covered by a smooth surface known as articular cartilage. Damage to this surface is called arthritis when it is generalized, or damage can occur in an isolated area, resulting in arthritis to a specific area. Injuries to the ligaments are common in sports. The Anterior Cruciate Ligament (ACL) tear is probably the injury most read about due to the notoriety of the athletes whose careers have been put on hold during the long recovery process. Other injuries include meniscus injuries. The meniscus is the cushioning cartilage of the knee and can be injured during sports.



  • Anterior Cruciate Ligament (ACL) Injury
  • Cartilage Lesions/Defect (Carticular Surface)
  • Medial Collateral Ligament (MCL) Injury
  • Meniscus Tears
  • Osgood-Schlatter Disease (PDF)
  • Osteochondritis Dissecans (OCD) of the Knee
  • Patellar (Kneecap) Instability
  • Patellar Tendinitis
  • Patellofemoral Pain
  • Sinding Larsen-Johansson (SLJ) Syndrome