The knee is a hinge joint that allows forward and backward movement of the lower leg. The three main bones that make up the knee are the femur (thigh bone), tibia (shin bone) and patella (kneecap). The patella makes up the anterior (front) portion of the knee joint. Ligaments attach the distal end of the femur to the proximal end of the tibia and provide stability to the knee in all directions. The Anterior Cruciate Ligament (ACL) and Posterior Cruciate Ligament (PCL) connect the bones at the center of the knee and prevent forward and backward movement of the tibia, respectively. The Medial Collateral Ligament (MCL) and Lateral Collateral Ligament (LCL) extend down the sides of the knee and provide stability to both the inside and outside of the knee, preventing sideways motion. The ligaments that make up the knee are commonly torn in pre-arthritic conditions, and these injuries often result from displacement of the leg caused by abrupt twisting, hyperextending, direct trauma and several other causes. Out of these four ligaments, the ACL is the ligament that often torn the most.
The knee is also a weight-bearing joint. The meniscus is a thick layer of specialized tissue that provides mechanical support to the knee by distributing forces across the joint and creating a smooth surface for the ends of the bones to move on. Meniscus tears result from twisting, squatting or trauma to the knee, and treatment is dependent on the location of the tear. The meniscus has its own blood supply, but only the outer third receives the greatest blood supply. The middle third receives some blood supply, but it is minimal, and the inner third receives no blood supply. The blood supply gives certain areas of the meniscus the ability to heal. The location of the meniscus tear, and thus, quality of the local blood supply, in addition to the nature of the tear will determine if a meniscus repair or meniscectomy is the appropriate surgical treatment. The ends of the bones in the joint are covered in a layer of cartilage, which acts to cushion and lubricate the joint, allowing for smooth motion. Acute damage to the articular cartilage that covers the surface of the femur and tibia can be very painful and cause swelling in the knee. Long term damage to this layer of cartilage can result in osteoarthritis. Osteoarthritis (arthritis) is a loss of the cartilage surface in a joint, resulting in painful bone-to-bone contact. When it becomes advanced and painful enough, the only available option is a total knee replacement, which removes the arthritic parts of the bone and replaces them with metal and plastic.
There are several other knee injuries that can cause pain and functional limitations of the knee. For example, patellofemoral injuries are a broad range of injuries that cause pain in the front of the knee around the patella. These injuries along with others and their respective treatments are listed below. Several of the surgical procedures listed below are performed arthroscopically, and they can help identify and repair knee injuries that involve the soft tissues (muscle, tendon, ligament) surrounding the knee joint. If you have any of the following conditions or undiagnosed knee pain, please contact us for an appointment.