Genu varum (also called bow-leggedness, bandiness, bandy-leg, and tibia vara) is a
varus deformity
A varus deformity is an excessive inward angulation ( medial angulation, that is, towards the body's midline) of the distal segment of a bone or joint. The opposite of varus is called valgus.
The terms varus and valgus always refer to the direc ...
marked by (outward) bowing at the
knee
In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...
, which means that the lower
leg
A leg is a weight-bearing and locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element cap ...
is angled inward (
medially) in relation to the
thigh
In anatomy, the thigh is the area between the hip (pelvis) and the knee. Anatomically, it is part of the lower limb.
The single bone in the thigh is called the femur. This bone is very thick and strong (due to the high proportion of bone tissu ...
's axis, giving the limb overall the appearance of an archer's
bow. Usually medial angulation of both lower limb bones (
fibula
The fibula (: fibulae or fibulas) or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. ...
and
tibia
The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two Leg bones, bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outsi ...
) is involved.
Causes
If a child is sickly, either with
rickets
Rickets, scientific nomenclature: rachitis (from Greek , meaning 'in or of the spine'), is a condition that results in weak or soft bones in children and may have either dietary deficiency or genetic causes. Symptoms include bowed legs, stun ...
or any other ailment that prevents ossification of the bones or is improperly fed, the bowed condition may persist. Thus the chief cause of this deformity is
rickets
Rickets, scientific nomenclature: rachitis (from Greek , meaning 'in or of the spine'), is a condition that results in weak or soft bones in children and may have either dietary deficiency or genetic causes. Symptoms include bowed legs, stun ...
. Skeletal problems,
infection
An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...
, and
tumor
A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...
s can also affect the growth of the leg, sometimes giving rise to a one-sided bow-leggedness. The remaining causes are occupational, especially among
jockey
A jockey is someone who rides horses in horse racing or steeplechase (horse racing), steeplechase racing, primarily as a profession. The word also applies to camel riders in camel racing. The word "jockey" originated from England and was used ...
s, and from
physical trauma
Injury is physiology, physiological damage to the living tissue of any organism, whether Injury in humans, in humans, Injury in animals, in other animals, or Injury in plants, in plants.
Injuries can be caused in many ways, including mechanic ...
, the condition being very likely to supervene after accidents involving the
condyles of the
femur
The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg.
The Femo ...
.
[
]
Childhood
Children until the age of 3 to 4 have a degree of genu varum. The child sits with the soles of the feet facing one another; the tibia
The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two Leg bones, bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outsi ...
and femur
The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg.
The Femo ...
are curved outwards; and, if the limbs are extended, although the ankles are in contact, there is a distinct space between the knee-joints. During the first year of life, a gradual change takes place. The knee-joints approach one another; the femur
The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg.
The Femo ...
slopes downward and inward towards the knee joints; the tibia
The tibia (; : tibiae or tibias), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two Leg bones, bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outsi ...
become straight, and the sole of the foot
The foot (: feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is an organ at the terminal part of the leg made up o ...
faces almost directly downwards.
While these changes are occurring, the bones, which at first consist principally of cartilage
Cartilage is a resilient and smooth type of connective tissue. Semi-transparent and non-porous, it is usually covered by a tough and fibrous membrane called perichondrium. In tetrapods, it covers and protects the ends of long bones at the joints ...
, are gradually becoming ossified
Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...
. By the time a normal child begins to walk, the lower limbs are prepared, both by their general direction and by the rigidity of the bones which form them, to support the weight of the body.
Rickets
Nutritional rickets
Rickets, scientific nomenclature: rachitis (from Greek , meaning 'in or of the spine'), is a condition that results in weak or soft bones in children and may have either dietary deficiency or genetic causes. Symptoms include bowed legs, stun ...
is an important cause of childhood genu varum or bow legs in some parts of the world. Nutritional rickets is due to unhealthy life style habits as insufficient exposure to sun light which is the main source of vitamin D. Insufficient dietary intake of calcium is another contributing factor. Rickets may also have genetic causes, occasionally called resistant rickets. Rickets usually causes bone deformities in all four extremities. Genu varum may resolve spontaneously with modification of life style activities or after receiving medical treatment. Some deformities do not correct spontaneously and need surgical intervention especially if they are severe and causing gait difficulties. The main surgical modality used to treat genu varum arising from rickets is guided growth surgery, also known as growth modulation surgery.
Blount's disease
Blount's disease
Blount's disease (or Blount disease) is a growth disorder of the tibia (shin bone) which causes the lower leg to angle inward, resembling a bowleg. It is also known as "tibia vara".
Signs and symptoms
Cause
Blount disease is a growth disorder of ...
is a deformity in the legs, mostly from the knees to the ankles. The affected bone curves in or out and forms the usual "archers bow" which can also be called bow-legs. There are two types of Blount's disease. The first type is Infantile: this means that children under four are diagnosed with this disease. Blount's disease in this age is very risky because sometimes it is not detected and it passes to the second type of Blount's disease. The second type of Blount's disease is found mostly in older children and in teenagers, sometimes in one leg and sometimes in both; the patient's age determines how severe the diagnosis is.
Osteochondrodysplasia
Osteochondrodysplasia
An osteochondrodysplasia,Etymology: . 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 t ...
are a diverse group of genetic bone diseases or genetic skeletal dysplasias that manifest in generalized bone deformities involving the extremities and the spine. Bow legs or genu varum is one of these deformities. The characteristic bone X-ray survey findings are important to confirm the diagnosis.
Diagnosis
On projectional radiography
Projectional radiography, also known as conventional radiography, is a form of radiography and medical imaging that produces two-dimensional images by X-ray radiation. The image acquisition is generally performed by radiographers, and the images a ...
, the degree of varus or valgus deformity can be quantified by the ''hip-knee-ankle angle'', which is an angle between the femoral mechanical axis and the center of the ankle joint
The ankle, the talocrural region or the jumping bone (informal) is the area 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. Th ...
. It is normally between 1.0° and 1.5° of varus in adults. Normal ranges are different in children.
File:Hip-knee-ankle angle by age.png, ''Hip-knee-ankle angle'' by age, with 95% prediction interval
In statistical inference, specifically predictive inference, a prediction interval is an estimate of an interval (statistics), interval in which a future observation will fall, with a certain probability, given what has already been observed. Pr ...
.[
]
Treatment
Generally, no treatment is required for idiopathic
An idiopathic disease is any disease with an unknown cause or mechanism of apparent spontaneous origin.
For some medical conditions, one or more causes are somewhat understood, but in a certain percentage of people with the condition, the cause ...
presentation as it is a normal anatomical variant in young children. Treatment is indicated when it persists beyond years old. In the case of unilateral presentation or progressive worsening of the curvature, when caused by rickets
Rickets, scientific nomenclature: rachitis (from Greek , meaning 'in or of the spine'), is a condition that results in weak or soft bones in children and may have either dietary deficiency or genetic causes. Symptoms include bowed legs, stun ...
, the most important thing is to treat the constitutional disease
A disease is a particular abnormal condition that adversely affects the structure or function (biology), function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical condi ...
, at the same time instructing the care-giver never to place the child on their feet. In many cases, this is quite sufficient in itself to effect a cure, but matters can be hastened somewhat by applying splints
Splints is an ailment of the horse or pony, characterized by a hard, bony swelling, usually on the inside of a front leg, lying between the splint and cannon bone or on the splint bone itself. It may be "hot," meaning that it occurred recently an ...
. When the deformity arises in older patients, either from trauma or occupation, the only permanent treatment is surgery
Surgery is a medical specialty that uses manual and instrumental techniques to diagnose or treat pathological conditions (e.g., trauma, disease, injury, malignancy), to alter bodily functions (e.g., malabsorption created by bariatric surgery s ...
, but orthopaedic
Orthopedic surgery or orthopedics ( alternative spelling orthopaedics) is the branch of surgery concerned with conditions involving the musculoskeletal system. Orthopedic surgeons use both surgical and nonsurgical means to treat musculoskeletal ...
bracing can provide relief.
Rickets
Rickets
Rickets, scientific nomenclature: rachitis (from Greek , meaning 'in or of the spine'), is a condition that results in weak or soft bones in children and may have either dietary deficiency or genetic causes. Symptoms include bowed legs, stun ...
usually causes bone deformities in all four extremities. Genu varum may resolve spontaneously with modification of lifestyle activities or after receiving medical treatment. Some deformities do not correct spontaneously and need surgical intervention especially if they are severe and causing gait difficulties. The main surgical modality used to treat genu varum arising from rickets
Rickets, scientific nomenclature: rachitis (from Greek , meaning 'in or of the spine'), is a condition that results in weak or soft bones in children and may have either dietary deficiency or genetic causes. Symptoms include bowed legs, stun ...
is guided growth surgery, also known as growth modulation surgery.
Blount's disease
Treatment for children with Blount's disease is typically braces but surgery may also be necessary. In children guided growth surgery is used to gradually correct/straighten the bow legs. For teenagers osteotomy or bone cutting is often used to correct the bone deformity. The operation consists of removing a piece of tibia, breaking the fibula and straightening out the bone; there is also a choice of elongating the legs. If not treated early enough, the condition worsens quickly.
Osteochondrodysplasia
Guided growth surgery in children is widely used to achieve gradual correction of knee deformities arising from Osteochondrodysplasia
An osteochondrodysplasia,Etymology: . 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 t ...
including genu varum. Yet, this treatment is associated with a high incidence of recurrence and repeated surgeries may be needed to maintain proper bone alignment.
Prognosis
In most cases persisting after childhood, there is little or no effect on the ability to walk. Due to uneven stress and wear on the knees, however, even milder manifestations can see an accelerated onset of arthritis
Arthritis is a general medical term used to describe a disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, Joint effusion, swelling, and decreased range of motion of ...
.
See also
* Genu valgum
Genu valgum, commonly called "knock-knee", is a condition in which the knees angle in and touch each other when the human leg, legs are straightened. Individuals with severe valgus deformity, valgus deformities are typically unable to touch thei ...
* Genu recurvatum
Genu recurvatum is a deformity in the knee joint, so that the knee bends backwards. In this deformity, excessive extension occurs in the tibiofemoral joint. Genu recurvatum is also called knee hyperextension and back knee. This deformity is more ...
* Varus deformity
A varus deformity is an excessive inward angulation ( medial angulation, that is, towards the body's midline) of the distal segment of a bone or joint. The opposite of varus is called valgus.
The terms varus and valgus always refer to the direc ...
* Rickets
Rickets, scientific nomenclature: rachitis (from Greek , meaning 'in or of the spine'), is a condition that results in weak or soft bones in children and may have either dietary deficiency or genetic causes. Symptoms include bowed legs, stun ...
* Knee pain
Knee pain is pain in or around the knee.
The knee joint consists of an articulation between four bones: the femur, tibia, fibula and patella. There are four compartments to the knee. These are the medial and lateral tibiofemoral compartments, the ...
* Knee osteoarthritis
In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...
References
External links
*
{{Congenital malformations and deformations of musculoskeletal system
Congenital disorders of musculoskeletal system
Knee injuries and disorders