The cause of fibular hemimelia is unclear. Purportedly, there have been some incidents of genetic distribution in a family; however, this does not account for all cases. Maternal viral infections, embryonic trauma, teratogenic environmental exposures or vascular dysgenesis (failure of the embryo to form a satisfactory blood supply) between four and seven weeks gestation are considered possible causes.

In an experimental mouse model, change in the expression of a homeobox gene led to similar, but bilateral, fibular defects.

Depending on the severity of the deformities, the treatment may include the amputation of the foot or part of the leg, lengthening of the femur, extension prosthesis, or custom shoe lifts. Amputation usually requires the use of prosthesis. Another alternative is a rotationplasty procedure, also known as Van Ness surgery. In this situation the foot and ankle are surgically removed, then attached to the femur. This creates a functional "knee joint". This allows the patient to be fit with a below knee prosthesis vs a traditional above knee prosthesis.

In less severe cases, the use of an Ilizarov apparatus can be successful in conjunction with hip and knee surgeries (depending on the status of the femoral head/kneecap) to extend the femur length to normal ranges. This method of treatment can be problematic in that the Ilizarov might need to be applied both during early childhood (to keep the femur from being extremely short at the onset of growth) and after puberty (to match leg lengths after growth has ended). The clear benefit of this approach, however, is that no prosthetics are needed and at the conclusion of surgical procedures the patient will not be biologically or anatomically different from a person born without PFFD.

There is no known cure. In selected patients orthopaedic surgery may be helpful to try to gain some functionality of severely impaired joints.

Fibular hemimelia or longitudinal fibular deficiency is "the congenital absence of the fibula and it is the most common congenital absence of long bone of the extremities." It is the shortening of the fibula at birth, or the complete lack thereof. In humans, the disorder can be noted by ultrasound in utero to prepare for amputation after birth or complex bone lengthening surgery. The amputation usually takes place at six months with removal of portions of the legs to prepare them for prosthetic use. The other treatments which include repeated corrective osteotomies and leg-lengthening surgery (Ilizarov apparatus) are costly and associated with residual deformity.

Children who develop severe bowing before the age of 3 may be treated with knee ankle foot orthoses. However, bracing may fail, or bowing may not be detected until the child is older. In some cases, surgery may be performed. Surgery may involve cutting the shin bone (tibia) to realign it, and sometimes lengthen it as well.

Other times, the growth of just the outer half of the tibia can be surgically restricted to allow the child’s natural growth to reverse the bowing process. This second, much smaller surgery is most effective in children with less severe bowing and significant growth remaining.

Return to normal function and cosmetic appearance is expected if the knee can be properly aligned.

The cause of PFFD is uncertain. Two hypotheses have been advanced. The theory of sclerotome subtraction posits injury to neural crest cells that are the precursors to sensory nerves at the level of L4 and L5. Histologic studies of a fetus with unilateral PFFD have prompted an alternative hypothesis that PFFD is caused by a defect in maturation of chondrocytes (cartilage cells) at the growth plate. In either hypothesis, the agent causing the injury is usually not known. Thalidomide is known to cause PFFD when the mother is exposed to it in the fifth or sixth week of pregnancy, and it is speculated that exposure to other toxins during pregnancy may also be a cause. Other etiologies that have been suggested, but not proven, include anoxia, ischemia, radiation, infection, hormones, and mechanical force. PFFD occurs sporadically, and does not appear to be hereditary.

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.

Studies suggest that prenatal care for mothers during their pregnancies can prevent congenital amputation. Knowing environmental and genetic risks is also important. Heavy exposure to chemicals, smoking, alcohol, poor diet, or engaging in any other teratogenic activities while pregnant can increase the risk of having a child born with a congenital amputation. Folic acid is a multivitamin that has been found to reduce birth defects.

Treatment for children with Blount's disease is typically braces but surgery may also be necessary, especially for teenagers. 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.

Hypophalangism is a congenital absence of one or more phalanges (bones of the fingers and toes).

Blount's disease occurs in young children and adolescents. The cause is unknown but is thought to be due to the effects of weight on the growth plate. The inner part of the tibia, just below the knee, fails to develop normally, causing angulation of the bone.

Unlike bowlegs, which tend to straighten as the child develops, Blount's disease is progressive and the condition worsens. It can cause severe bowing of the legs and can affect one or both legs.

This condition is more common among children of African ancestry. It is also associated with obesity, short stature, and early walking. There does not appear to be an obvious genetic factor.

It can result from syphilis, yaws, Paget's disease of bone, Vitamin D deficiency, or Weismann-Netter-Stuhl syndrome.

It can be due to osteomalacia

Saber refers to the tibia's resemblance to the curve of a saber sword.

Surgical excision is performed when exostoses lead to growth disturbances or lead to disability. Knee osteotomies are associated with high incidence of peroneal nerve paralysis.

Surgery, physical therapy and pain management are currently the only options available to HME patients, but success varies from patient to patient and many struggle with pain, fatigue and mobility problems throughout their lives.

It is not uncommon for HME patients to undergo numerous surgical procedures throughout their lives to remove painful or deforming exostoses, correct limb length discrepancies or improve range of motion. Usually the treatment can be problematic. The osteochondromas can return in the same places and may be more painful.

Langer mesomelic dysplasia (LMD) is a rare congenital disorder characterized by an altered bone formation that causes a severe short and disproportionate stature.

Léri–Weill dyschondrosteosis or LWD is a rare pseudoautosomal dominant genetic disorder which results in dwarfism with short forearms and legs (mesomelic dwarfism) and a bayonet-like deformity of the forearms (Madelung's deformity).

Diplopodia is a congenital anomaly in tetrapods that involves duplication of elements of the foot on the hind limb. It comes from the Greek roots diplo = "double" and pod = "foot". Diplopodia is often found in conjunction with other structural abnormalities and can be lethal. It is more extreme than polydactyly, the presence of extra digits.

This can be done by annual evaluations by multidiciplinary team involving otolaryngologist, clinical geneticist, a pediatrician, the expertise of an educator of the deaf, a neurologist is appropriate.

Most of these conditions are self-correcting during childhood. In the worst cases, surgery may be needed. Most of the time, this involves lengthening the Achilles tendon. Less severe treatment options for pigeon toe include keeping a child from crossing his or her legs, use of corrective shoes, and casting of the foot and lower legs, which is normally done before the child reaches 12 months of age or older.

If the pigeon toe is mild and close to the center, treatment may not be necessary.

Ballet has been used as a treatment for mild cases. Dance exercises can help to bend the legs outward.

It is caused by mutations in the SHOX gene found in the pseudoautosomal region PAR1 of the X and Y chromosomes, at band Xp22.33 or Yp11.32.

SHOX gene deletions have been identified as the major cause of Leri–Weill syndrome.

Leri–Weill dyschondrosteosis is characterized by mesomelic short stature, with bowing of the radius more so than the ulna in the forearms and bowing of the tibia while sparing the fibula.

Treatment consist of a long leg orthopedic cast for several weeks.

Hemimelia comprises

- Fibular hemimelia, Congenital longitudinal deficiency of the fibula or Fibular longitudinal meromelia

- Tibial hemimelia, Congenital longitudenal deficiency of the tibia, Congenital aplasia and dysplasia of the tibia with intact fibula, Congenital longitudinal deficiency of the tibia or Tibial longitudinal meromelia

- Radial Hemimelia, Congenital longitudinal deficiency of the radius, Radial clubhand, Radial longitudinal meromelia or Radial ray agenesis

- Ulnar hemimelia, Congenital longitudinal deficiency of the ulna, Ulnar clubhand or Ulnar longitudinal meromelia

Treatment generally includes the following:

- Sometimes pharmacologic therapy for initial disease treatment

- Physical therapy

- Occupational therapy

- Use of appropriate assistive devices such as orthoses

- Surgical treatment

Presence of inner ear abnormalities lead to Delayed gross development of child because of balance impairment and profound deafness which increases the risk of trauma and accidents.

- Incidence of accidents can be decreased by using visual or vibrotactile alarm systems in homes as well as in schools.

- Anticipatory education of parents, health providers and educational programs about hazards can help.

The exact cause of congenital amputation is unknown and can result from a number of causes. However, most cases show that the first three months in a pregnancy are when most birth defects occur because that is when the organs of the fetus are beginning to form. One common cause is amniotic band syndrome, which occurs when the inner fetal membrane (amnion) ruptures without injury to the outer membrane (chorion). Fibrous bands from the ruptured amnion float in the amniotic fluid and can get entangled with the fetus, thus reducing blood supply to the developing limbs to such an extent that the limbs can become strangulated; the tissues die and are absorbed into the amniotic fluid. A baby with congenital amputation can be missing a portion of a limb or the entire limb, which results in the complete absence of a limb beyond a certain point where only a stump is left is known as transverse deficiency or amelia. When a specific part is missing, it is referred to as longitudinal deficiency. Finally, phocomelia occurs when only a mid-portion of a limb is missing; for example when the hands or feet are directly attached to the trunk of the body.

Amnion ruptures can be caused by:

- teratogenic drugs (e.g. thalidomide, which causes phocomelia), or environmental chemicals

- ionizing radiation (atomic weapons, radioiodine, radiation therapy)

- infections

- metabolic imbalance

- trauma

Congenital amputation is the least common reason for amputation, but it is projected that one in 2000 babies are born each year with a missing or deformed limb. During certain periods in history, an increase in congenital amputations has been documented. One example includes the thalidomide tragedy that occurred in the 1960s when pregnant mothers were given a tranquilizer that contained the harmful drug, which produced an increase in children born without limbs. Another example was the 1986 Chernobyl catastrophe in Ukraine, where the radiation exposure caused many children to be born with abnormal or missing limbs .