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.
An epiphysis is one of the rounded ends or tips of a long bone that ossify from one or more secondary centers of ossification. Between the epiphysis and diaphysis lies the metaphysis, including the epiphyseal plate. During formation of the secondary ossification center, vascular canals stemming from the perichondrium invade the epiphysis, supplying nutrients to the developing secondary centers of ossification. At the joint, the epiphysis is covered with articular cartilage; below that covering is a zone similar to the epiphyseal plate, known as subchondral bone. The epiphysis is mostly found in mammals but it is also present in some lizards. However, the secondary center of ossification may have evolved multiple times, having been found in the Jurassic sphenodont Sapheosaurus as well as in the therapsid Niassodon mfumukasi.
An osteotomy is a surgical operation whereby a bone is cut to shorten or lengthen it or to change its alignment. It is sometimes performed to correct a hallux valgus, or to straighten a bone that has healed crookedly following a fracture. It is also used to correct a coxa vara, genu valgum, and genu varum. The operation is done under a general anaesthetic.
Genu valgum, commonly called "knock-knee", is a condition in which the knees angle in and touch each other when the legs are straightened. Individuals with severe valgus deformities are typically unable to touch their feet together while simultaneously straightening the legs. The term originates from Latin genu 'knee' and valgus 'bent outwards', but is also used to describe the distal portion of the knee joint which bends outwards and thus the proximal portion seems to be bent inwards.
Genu varum is a varus deformity marked by (outward) bowing at the knee, which means that the lower leg is angled inward (medially) in relation to the thigh's axis, giving the limb overall the appearance of an archer's bow. Usually medial angulation of both lower limb bones is involved.
Hereditary multiple osteochondromas (HMO), also known as hereditary multiple exostoses, is a disorder characterized by the development of multiple benign osteocartilaginous masses (exostoses) in relation to the ends of long bones of the lower limbs such as the femurs and tibias and of the upper limbs such as the humeri and forearm bones. They are also known as osteochondromas. Additional sites of occurrence include on flat bones such as the pelvic bone and scapula. The distribution and number of these exostoses show a wide diversity among affected individuals. Exostoses usually present during childhood. The vast majority of affected individuals become clinically manifest by the time they reach adolescence. The incidence of hereditary multiple exostoses is around 1 in 50,000 individuals. Hereditary multiple osteochondromas is the preferred term used by the World Health Organization. A small percentage of affected individuals are at risk for development of sarcomas as a result of malignant transformation. The risk that people with hereditary multiple osteochondromas have a 1 in 20 to 1 in 200 lifetime risk of developing sarcomas.
Chondrocytes are the only cells found in healthy cartilage. They produce and maintain the cartilaginous matrix, which consists mainly of collagen and proteoglycans. Although the word chondroblast is commonly used to describe an immature chondrocyte, the term is imprecise, since the progenitor of chondrocytes can differentiate into various cell types, including osteoblasts.
Endochondral ossification is one of the two essential pathways by which bone tissue is produced during fetal development of the mammalian skeletal system, the other pathway being intramembranous ossification. Both endochondral and intramembranous processes initiate from a precursor mesenchymal tissue, but their transformations into bone are different. In intramembranous ossification, mesenchymal tissue is directly converted into bone. On the other hand, endochondral ossification starts with mesenchymal tissue turning into an intermediate cartilage stage, which is eventually substituted by bone.
Proximal femoral focal deficiency (PFFD), also known as Congenital Femoral Deficiency (CFD), is a rare, non-hereditary birth defect that affects the pelvis, particularly the hip bone, and the proximal femur. The disorder may affect one side or both, with the hip being deformed and the leg shortened.
Osteochondromas are the most common benign tumors of the bones. The tumors take the form of cartilage-capped bony projections or outgrowth on the surface of bones (exostoses). It is characterized as a type of overgrowth that can occur in any bone where cartilage forms bone. Tumors most commonly affect long bones about the knee and in the forearm. Additionally, flat bones such as the pelvis and scapula may be affected.
Chondropathy refers to a disease of the cartilage. It is frequently divided into 5 grades, with 0-2 defined as normal and 3-4 defined as diseased.
Osteochondritis dissecans is a joint disorder primarily of the subchondral bone in which cracks form in the articular cartilage and the underlying subchondral bone. OCD usually causes pain during and after sports. In later stages of the disorder there will be swelling of the affected joint that catches and locks during movement. Physical examination in the early stages does only show pain as symptom, in later stages there could be an effusion, tenderness, and a crackling sound with joint movement.
An osteochondrodysplasia, or skeletal dysplasia, is a disorder of the development of bone and cartilage. Osteochondrodysplasias are rare diseases. About 1 in 5,000 babies are born with some type of skeletal dysplasia. Nonetheless, if taken collectively, genetic skeletal dysplasias or osteochondrodysplasias comprise a recognizable group of genetically determined disorders with generalized skeletal affection. These disorders lead to disproportionate short stature and bone abnormalities, particularly in the arms, legs, and spine. Skeletal dysplasia can result in marked functional limitation and even mortality.
A Salter–Harris fracture is a fracture that involves the epiphyseal plate of a bone, specifically the zone of provisional calcification. It is thus a form of child bone fracture. It is a common injury found in children, occurring in 15% of childhood long bone fractures. This type of fracture and its classification system is named for Robert B. Salter and William H. Harris who created and published this classification system in the Journal of Bone and Joint Surgery in 1963.
Multiple epiphyseal dysplasia (MED), also known as Fairbank's disease, is a rare genetic disorder that affects the growing ends of bones. Long bones normally elongate by expansion of cartilage in the growth plate near their ends. As it expands outward from the growth plate, the cartilage mineralizes and hardens to become bone (ossification). In MED, this process is defective.
Pseudoachondroplasia is an inherited disorder of bone growth. It is a genetic autosomal dominant disorder. It is generally not discovered until 2–3 years of age, since growth is normal at first. Pseudoachondroplasia is usually first detected by a drop of linear growth in contrast to peers, a waddling gait or arising lower limb deformities.
Blount's disease is a growth disorder of the tibia which causes the lower leg to angle inward, resembling a bowleg. It is also known as "tibia vara".
Boomerang dysplasia is a lethal form of osteochondrodysplasia known for a characteristic congenital feature in which bones of the arms and legs are malformed into the shape of a boomerang. Death usually occurs in early infancy due to complications arising from overwhelming systemic bone malformations.
Epiphysiodesis is a pediatric orthopedic surgery procedure that aims at altering or stopping the bone growth naturally occurring through the growth plate also known as the physeal plate. There are two types of epiphysiodesis: temporary hemiepiphysiodesis and permanent epiphysiodesis. Temporary hemiepiphysiodesis is also known as guided growth surgery or growth modulation surgery. Temporary hemiepiphysiodesis is reversible i.e. the metal implants used to achieve epiphysiodesis can be removed after the desired correction is achieved and the growth plate can thus resume its normal growth and function. In contrast, permanent epiphysiodesis is irreversible and the growth plate function cannot be restored after surgery. Both temporary hemiepiphysiodesis and permanent epiphysiodesis are used to treat a diverse array of pediatric orthopedic disorders but the exact indications for each procedure are different.
Orthopedic surgery is the branch of surgery concerned with conditions involving the musculoskeletal system. Orthopedic surgeons use both surgical and nonsurgical means to treat musculoskeletal injuries, sports injuries, degenerative diseases, infections, bone tumours, and congenital limb deformities. Trauma surgery and traumatology is a sub-specialty dealing with the operative management of fractures, major trauma and the multiply-injured patient.
