Coxa vara

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Coxa vara
FemurAngles.jpg
Left to right: coxa vara, normal femur, coxa valga
Specialty Medical genetics

Coxa vara is a deformity of the hip, whereby the angle between the head and the shaft of the femur is reduced to less than 120 degrees. This results in the leg being shortened and the development of a limp. It may be congenital and is commonly caused by injury, such as a fracture. It can also occur when the bone tissue in the neck of the femur is softer than normal, causing it to bend under the weight of the body. This may either be congenital or the result of a bone disorder. The most common cause of coxa vara is either congenital or developmental. Other common causes include metabolic bone diseases (e.g. Paget's disease of bone), post-Perthes deformity, osteomyelitis, and post traumatic (due to improper healing of a fracture between the greater and lesser trochanter). Shepherd's Crook deformity is a severe form of coxa vara where the proximal femur is severely deformed with a reduction in the neck shaft angle beyond 90 degrees. It is most commonly a sequela of osteogenesis imperfecta, Paget's disease, osteomyelitis, tumour and tumour-like conditions (e.g. fibrous dysplasia).

Contents

Coxa vara can happen in cleidocranial dysostosis.

Anatomy

In early skeletal development, a common physis serves the greater trochanter and the capital femoral epiphysis. This physis divides as growth continues in a balance that favors the capital epiphysis and creates a normal neck shaft angle (angle between the femoral shaft and the neck). The corresponding angle at maturity is 135 ± 7 degrees. Another angle used for the measurement of coxa vara is the cervicofemoral angle which is approximately 35 degrees at infancy and increases to 45 degrees after maturity.

Types

Developmental

Clinical feature: presents after the child has started walking but before six years of age. Usually associated with a painless hip due to mild abductor weakness and mild limb length discrepancy.

If there is a bilateral involvement the child might have a waddling gait or trendelenburg gait with an increased lumbar lordosis. The greater trochanter is usually prominent on palpation and is more proximal. Restricted abduction and internal rotation.

X-ray: decreased neck shaft angle, increased cervicofemoral angle, vertical physis, shortened femoral neck decrease in femoral anteversion. HE angle (Hilgenriener epiphyseal angle- angle subtended between a horizontal line connecting the triradiate cartilage and the epiphysis); normal angle is <30 degrees.

Treatment: HE angle of 45–60 degrees: observation and periodic follow up.

Indication for surgery: HE angle more than 60 degrees, progressive deformity, neck-shaft angle <90 degrees, development of Trendelenburg gait

Surgery: subtrochanteric valgus osteotomy with adequate internal rotation of distal fragment to correct anteversion; common complication is recurrence. If HE angle is reduced to 38 degrees, less evidence of recurrence; post operative spica cast is used for a period of 6–8 weeks.

Coxa vara is also seen in Niemann–Pick disease.

Congenital

Presence at birth is extremely rare and associated with other congenital anomalies such as proximal femoral focal deficiency, fibular hemimelia or anomalies in other part of the body such as cleidocranial dyastosis. The femoral deformity is present in the subtrochanteric area where the bone is bent. The cortices are thickened and may be associated with overlying skin dimples. External rotation of the femur with valgus deformity of knee may be noted. This condition does not resolve and requires surgical management. Surgical management includes valgus osteotomy to improve hip biomechanics and length and rotational osteotomy to correct retroversion and lengthening.

See also

Related Research Articles

<span class="mw-page-title-main">Femur</span> Thigh bone

The femur, or thigh bone is the only bone in the thigh. The thigh is the region of the lower limb between the hip and the knee. In many four-legged animals the femur is the upper bone of the hindleg.

<span class="mw-page-title-main">Legg–Calvé–Perthes disease</span> Osteochondrosis that results in death and fracture located in hip joint

Legg–Calvé–Perthes disease (LCPD) is a childhood hip disorder initiated by a disruption of blood flow to the head of the femur. Due to the lack of blood flow, the bone dies and stops growing. Over time, healing occurs by new blood vessels infiltrating the dead bone and removing the necrotic bone which leads to a loss of bone mass and a weakening of the femoral head.

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.

<span class="mw-page-title-main">Genu valgum</span> Medical condition known as knock-knee

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 the Latin genu, 'knee', and valgus which means "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.

<span class="mw-page-title-main">Genu varum</span> Varus deformity marked by (outward) bowing at the knee

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.

<span class="mw-page-title-main">Varus deformity</span> Deformity in which the bone near a joint is angled inward

A varus deformity is an excessive inward angulation of the distal segment of a bone or joint. The opposite of varus is called valgus. EX: Varus deformity results in a decreased Q angle of the knee joint.

<span class="mw-page-title-main">Valgus deformity</span> Deformity in which the bone near a joint is angled outward

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<span class="mw-page-title-main">Limp</span> Type of asymmetric abnormality of the gait

A limp is a type of asymmetric abnormality of the gait. Limping may be caused by pain, weakness, neuromuscular imbalance, or a skeletal deformity. The most common underlying cause of a painful limp is physical trauma; however, in the absence of trauma, other serious causes, such as septic arthritis or slipped capital femoral epiphysis, may be present. The diagnostic approach involves ruling out potentially serious causes via the use of X-rays, blood tests, and sometimes joint aspiration. Initial treatment involves pain management. A limp is the presenting problem in about 4% of children who visit hospital emergency departments.

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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.

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Slipped capital femoral epiphysis is a medical term referring to a fracture through the growth plate (physis), which results in slippage of the overlying end of the femur (metaphysis).

Trendelenburg gait, named after Friedrich Trendelenburg, is an abnormal gait. It is caused by weakness or ineffective action of the gluteus medius muscle and the gluteus minimus muscle.

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<span class="mw-page-title-main">Upper extremity of femur</span>

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<span class="mw-page-title-main">Femoral neck</span>

The femoral neck is a flattened pyramidal process of bone, connecting the femoral head with the femoral shaft, and forming with the latter a wide angle opening medialward.

<span class="mw-page-title-main">Coxa valga</span> Medical condition

Coxa valga is a deformity of the hip where the angle formed between the head and neck of the femur and its shaft is increased, usually above 135 degrees.

<span class="mw-page-title-main">Pigeon toe</span> Medical condition affecting the feet

Pigeon toe, also known as in-toeing, is a condition which causes the toes to point inward when walking. It is most common in infants and children under two years of age and, when not the result of simple muscle weakness, normally arises from underlying conditions, such as a twisted shin bone or an excessive anteversion resulting in the twisting of the thigh bone when the front part of a person's foot is turned in.

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References