In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia, and one between the femur and patella. It is the largest joint in the human body. The knee is a modified hinge joint, which permits flexion and extension as well as slight internal and external rotation. The knee is vulnerable to injury and to the development of osteoarthritis.
The ankle, or the talocrural region, is the region where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular joint. The movements produced at this joint are dorsiflexion and plantarflexion of the foot. In common usage, the term ankle refers exclusively to the ankle region. In medical terminology, "ankle" can refer broadly to the region or specifically to the talocrural joint.
A sprain, also known as a torn ligament, is the stretching or tearing of ligaments within a joint, often caused by an injury abruptly forcing the joint beyond its functional range of motion. Ligaments are tough, inelastic fibers made of collagen that connect two or more bones to form a joint and are important for joint stability and proprioception, which is the body's sense of limb position and movement. Sprains can occur at any joint but most commonly occur in the ankle, knee, or wrist. An equivalent injury to a muscle or tendon is known as a strain.
The posterior cruciate ligament (PCL) is a ligament in each knee of humans and various other animals. It works as a counterpart to the anterior cruciate ligament (ACL). It connects the posterior intercondylar area of the tibia to the medial condyle of the femur. This configuration allows the PCL to resist forces pushing the tibia posteriorly relative to the femur.
The anterior cruciate ligament (ACL) is one of a pair of cruciate ligaments in the human knee. The two ligaments are also called "cruciform" ligaments, as they are arranged in a crossed formation. In the quadruped stifle joint, based on its anatomical position, it is also referred to as the cranial cruciate ligament. The term cruciate translates to cross. This name is fitting because the ACL crosses the posterior cruciate ligament to form an “X”. It is composed of strong, fibrous material and assists in controlling excessive motion. This is done by limiting mobility of the joint. The anterior cruciate ligament is one of the four main ligaments of the knee, providing 85% of the restraining force to anterior tibial displacement at 30 and 90° of knee flexion. The ACL is the most injured ligament of the four located in the knee.
A joint dislocation, also called luxation, occurs when there is an abnormal separation in the joint, where two or more bones meet. A partial dislocation is referred to as a subluxation. Dislocations are often caused by sudden trauma on the joint like an impact or fall. A joint dislocation can cause damage to the surrounding ligaments, tendons, muscles, and nerves. Dislocations can occur in any joint major or minor. The most common joint dislocation is a shoulder dislocation.
The ulnar collateral ligament is a thick triangular band at the medial aspect of the elbow uniting the distal aspect of the humerus to the proximal aspect of the ulna.
The medial collateral ligament (MCL), or tibial collateral ligament (TCL), is one of the four major ligaments of the knee. It is on the medial (inner) side of the knee joint in humans and other primates. Its primary function is to resist outward turning forces on the knee.
The talus, talus bone, astragalus, or ankle bone is one of the group of foot bones known as the tarsus. The tarsus forms the lower part of the ankle joint. It transmits the entire weight of the body from the lower legs to the foot.
The Broström operation is a repair of ligaments on lateral ankle. It is designed to address ankle instability. More importantly, it is primarily used to repair the anterior talofibular ligament (ATFL) in the ankle. It is thought that the majority of patients regain most function in their ankles. The recovery time for the procedure varies according to the patient but usually takes a minimum of 3–6 months.
An ankle fracture is a break of one or more of the bones that make up the ankle joint. Symptoms may include pain, swelling, bruising, and an inability to walk on the injured leg. Complications may include an associated high ankle sprain, compartment syndrome, stiffness, malunion, and post-traumatic arthritis.
A sprained ankle, also known as a twisted ankle, or rolled ankle is an injury where sprain occurs on one or more ligaments of the ankle.
An anterior cruciate ligament injury occurs when the anterior cruciate ligament (ACL) is either stretched, partially torn, or completely torn. The most common injury is a complete tear. Symptoms include pain, a popping sound during injury, instability of the knee, and joint swelling. Swelling generally appears within a couple of hours. In approximately 50% of cases, other structures of the knee such as surrounding ligaments, cartilage, or meniscus are damaged.
The lateral collateral ligament of ankle joint are ligaments of the ankle which attach to the fibula.
The anterior talofibular ligament is a ligament in the ankle. It passes from the anterior margin of the fibular malleolus, anteriorly and laterally, to the talus bone, in front of its lateral articular facet. It is one of the lateral ligaments of the ankle and prevents the foot from sliding forward in relation to the shin. It is the most commonly injured ligament in a sprained ankle—from an inversion injury—and will allow a positive anterior drawer test of the ankle if completely torn.
The unhappy triad, also known as a blown knee among other names, is an injury to the anterior cruciate ligament, medial collateral ligament, and meniscus. Analysis during the 1990s indicated that this 'classic' O'Donoghue triad is actually an unusual clinical entity among athletes with knee injuries. Some authors mistakenly believe that in this type of injury, "combined anterior cruciate and medial collateral ligament disruptions that were incurred during athletic endeavors" always present with concomitant medial meniscus injury. However, the 1990 analysis showed that lateral meniscus tears are more common than medial meniscus tears in conjunction with sprains of the ACL.
A malleolus is the bony prominence on each side of the human ankle.
A high ankle sprain, also known as a syndesmotic ankle sprain (SAS), is a sprain of the syndesmotic ligaments that connect the tibia and fibula in the lower leg, thereby creating a mortise and tenon joint for the ankle. High ankle sprains are described as high because they are located above the ankle. They comprise approximately 15% of all ankle sprains. Unlike the common lateral ankle sprains, when ligaments around the ankle are injured through an inward twisting, high ankle sprains are caused when the lower leg and foot externally rotates.
The anterolateral ligament (ALL) is a ligament on the lateral aspect of the human knee, anterior to the fibular collateral ligament.
A knee dislocation is a knee injury in which there is a complete disruption of the joint between the tibia and the femur. Symptoms include knee pain and instability of the knee. Complications may include injury to an artery around the knee, most commonly the artery behind the knee, or compartment syndrome.
