The anterior cruciate ligament (ACL) is one of the major ligaments of the knee. It is located in the middle of the knee and runs from the femur (thighbone) to the tibia (shinbone). The ACL prevents the tibia from sliding out in front of the femur. Together with the posterior cruciate ligament (PCL), it provides rotational stability to the knee.
A meniscal tear is a common knee injury in athletes, especially those involved in contact sports. A sudden bend or twist in your knee causes the meniscus to tear. Elderly people are more prone to degenerative meniscal tears as the cartilage wears out and weakens with age.
Any damage to the supporting ligaments may cause the patella to slip out of the groove either partially (subluxation) or completely (dislocation). This misalignment can damage the underlying soft structures such as muscles and ligaments that hold the kneecap in place. Once damaged, these soft structures are unable to keep the patella (kneecap) in position.
Articular Cartilage Injury (Knee)
Articular or hyaline cartilage is the tissue lining the surface of the two bones in the knee joint. Cartilage helps the bones move smoothly against each other and can withstand the weight of the body during activities such as running and jumping.
Knee arthritis causes pain and decreased mobility of the knee joint. The cartilage lining is thinner than normal or completely absent. In the arthritic knee, there is an absent joint space that shows on X-ray. In the normal knee, there is a normal joint space.
Knee Ligament Injuries
The knee is a hinge joint made up of two bones, the thighbone (femur) and shinbone (tibia). Ligaments are tough bands of tissue that connect one bone to another bone. The ligaments of the knee stabilize the knee joint. There are two important groups of ligaments that hold the bones of the knee joint together, collateral and cruciate ligaments - medial collateral ligament (MCL) and lateral collateral ligament (LCL), and anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL).
Multiligament Knee Injuries
Multiligament knee injuries may be mild or severe. Mild sprains do not damage the stability of the joint. A tear in the ligaments may be partial or complete. Partial tears cause loosening of the joint whereas, complete tearing of the ligament causes the joint to be unstable.
Patellar Tendon Rupture
The patellar tendon works together with the quadriceps muscle and the quadriceps tendon to allow your knee to straighten out. Patella tendon rupture is the rupture of the tendon that connects the patella (kneecap) to the top portion of the tibia (shinbone).
Knee sprain is a common injury that occurs from overstretching of the ligaments that support the knee joint. A knee sprain occurs when the knee ligaments are twisted or turned beyond its normal range, causing the ligaments to tear.
Jumper’s knee, also known as patellar tendinitis, is inflammation of the patellar tendon that connects your kneecap (patella) to your shinbone. This tendon helps in the extension of the lower leg.
Knee dislocation is a condition that occurs when the bones that form the knee joint, namely the femur or thigh bone get separated from the shin bone. This can cause serious damage to the nerves, blood vessels, and ligaments surrounding the knee, leading to a decline in strength and overall health of the leg.
Damage to any of these supportive structures causes instability of the knee joint. An unstable knee can be caused by the sudden twisting of the knee, tears of the meniscus, ligament or capsule, osteoarthritis of the knee (wear and tear of the cushioning cartilage tissue between the bones) and sports injuries.
Knee Sports Injuries
Knee injuries in sports may require surgical intervention that can be performed using open surgical or minimally invasive technique. Your surgeon will recommend physical therapy to strengthen your muscles, improve elasticity and improve the movements of the bones and joints.
A fracture is a condition in which there is a break in the continuity of the bone. In younger individuals, these fractures are caused by high energy injuries, as from a motor vehicle accident. In older people, the most common cause is a weak and fragile bone.