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.
The joint surface is covered by a smooth articular surface that allows pain-free movement in the joint. Arthritis is a general term covering numerous conditions where the joint surface or cartilage wears out. This surface can wear out for several reasons; often the definite cause is not known. Arthritis often affects the knee joint. When the articular cartilage wears out, the bone ends rub on one another and cause pain. The most common type of arthritis is osteoarthritis. It occurs with aging and use.
Meniscal root tears are characterized as soft tissue or bony root avulsion injuries or radial tears located within 1 cm of meniscus root attachment. They can be either a tear which disconnects the root area completely from the body of the meniscus (complete radial tear) or a disruption of the meniscus attachment directly from the bone (true meniscus root tear) that can cause the whole meniscus to lose its capacity to safeguard the underlying cartilage.
The medial collateral ligament (MCL), a band of tissue present on the inside of your knee joint, connects your thighbone and shinbone (bone of your lower leg). The MCL maintains the integrity of the knee joint and prevents it from bending inward.
Posterior cruciate ligament (PCL), one of the four major ligaments of the knee, is situated at the back of the knee. It connects the thighbone (femur) to the shinbone (tibia). The PCL limits the backward motion of the shinbone.
Posterolateral corner (PLC) injuries are defined as damage to a complex area of the knee formed by the association of 3 main structures of the knee, namely popliteus tendon, popliteofibular ligament, and lateral (fibular) collateral ligament. Injuries to the posterolateral corner often occur in combination with anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) tears with isolated PCL injuries occurring rarely. PLC injuries most commonly occur as a result of motor vehicle accidents and sports activities. Left untreated, it can lead to chronic pain, instability, and early degenerative changes of the knee joint.
Injury to more than one knee ligament is called a multiligament knee injury and may occur during sports or other physical activities.
An osteochondral defect, also commonly known as osteochondritis dissecans, of the knee refers to a damage or injury to the smooth articular cartilage surrounding the knee joint and the bone underneath the cartilage. The degree of damage may range from a rupture of the cartilage to a slight crack of the bone to a piece of the bone breaking off within the joint. These pieces may vary in size and depth and may remain stable or unstable within the joint. These may occur from an acute traumatic injury to the knee or an underlying disorder of the bone. Osteochondral defect is more common among young athletes who actively take part in sports and most commonly affects the femoral condyles in the knee.
Patellofemoral arthritis is an inflammatory condition characterized by loss of the smooth cartilage between the kneecap (patella) and the underlying femoral (thigh) bone in the knee joint. When the articular cartilage wears out, the underlying bones rub against each other, causing pain, swelling, stiffness, and restricted movement.
Chondromalacia patella is a common condition characterized by softening, weakening and damage of the cartilage. The condition is most often seen in young athletes and older adults who have arthritis of the knee. It especially occurs in women.
Loose bodies are fragments of detached cartilage or bone inside the knee joint. These fragments may be free floating (unstable) or may be trapped (stable) within the joint. Depending on the severity, you may have one or more loose bodies in your knee joint.
Patellar tendinitis, also known as "jumper's knee", is an inflammation of the patellar tendon that connects your kneecap (patella) to your shinbone. This tendon helps in extension of the lower leg.
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).
The quadriceps can rupture after a fall, direct blow to the leg and when you land on your leg awkwardly from a jump. Quadriceps tendon rupture most commonly occurs in middle-aged people who participate in sports that involve jumping and running. Other causes include tendonitis (inflammation of quadriceps tendon), diseases such as rheumatoid arthritis, diabetes mellitus, infection and chronic renal failure, which weaken the quadriceps tendon. Use of medications such as steroids and some antibiotics also weakens the quadriceps tendon.
Osteochondritis dissecans is a joint condition in which a piece of cartilage, along with a thin layer of the bone separates from the end of the bone because of inadequate blood supply. The separated fragments are sometimes called “joint mice”. These fragments may be localized or may detach and fall into the joint space, causing pain and joint instability. Osteochondritis dissecans occurs within the lateral aspect of the medial femoral condyle. The condition can also occur in other joints, including your elbows, ankles, shoulders, and hips.
Osgood-Schlatter disease refers to a condition in older children and teenagers caused by excessive stress to the patellar tendon (located below the kneecap). Participants in sports such as soccer, gymnastics, basketball, and distance running are at higher risk for this disease.
Osteonecrosis is a condition in which the death of a section of bone occurs because of lack of blood supply to it. It is one of the most common causes of knee pain in older women. Women over 60 years of age are commonly affected, three times more often than men.