Fibular hemimelia is the congenital absence or underdevelopment of the fibula (medical name fibula). The condition is also called fibular longitudinal defect. It can occur either in isolation or in combination with malformations of the femur, malformations of the feet, or with shortening of the entire lower leg bone.
What is fibular hemimelia?
Fibular hemimelia is a condition that is very rare. It occurs in only three out of every 100,000 newborns. At the same time, males are affected by fibular hemimelia twice as often as females. In two thirds of all affected persons, only one leg is affected by the malformation. Fibular hemimelia occurs more frequently on the right leg than on the left. The congenital, complete absence of a tibia, known as tibial hemimelia, occurs even more rarely. Fibular hemimelia is characterized by a congenital and longitudinal defect and has a wide spectrum of deformities.
Causes
Potential causes of fibular hemimelia have not been explored to a sufficient degree at this time to provide definite information about them. However, the search for causes of the disease has been the subject of medical research for some time. Fibular hemimelia has a familial clustering, leading to the conclusion that it is a congenital disorder with hereditary causes. The malformation could have its origin in the disturbance of a critical period in the development of the limbs in the embryo. This is in the period between the fourth and seventh weeks of pregnancy. In addition, viral infections, vascular dysgenesis, trauma and various environmental factors are discussed as potential causes. In the case of a familial clustered occurrence of fibular hemimelia, autosomal dominant inheritance has been inferred.
Symptoms, complaints, and signs
The symptoms and complaints associated with fibular hemimelia can be varied. The primary functional symptom of the condition is shortening of the affected leg, which increases during the growth phase. In most cases, the foot is also affected by the disease, often with a so-called bent and pointed foot position. Only medial rays of the affected foot are present. In addition, parts of the hindfoot are sometimes missing. In numerous cases, the entire lower leg is underdeveloped or hypoplastic. In addition, femoral hypoplasia is often present in conjunction with fibular hemimelia. Also a so-called ball joint deformity in the ankle joint with disturbed joint mechanics is often associated with fibular hemimelia. Other deformities that often occur in combination with fibular hemimelia may include proximal femoral defect, malformations of the toes, or craniosynostosis. Fibular hemimelia may also occur in association with dysplasias of the skeleton. The bone affected by the disease has only a low growth potential, so the deformity increases with age. In rare cases, fibular hemimelia is associated with other malformations that are outside the skeletal system, such as heart defects, thrombocytopenia, kidney dysplasia, or malformations of the eyes. Intellectual deficits, however, rarely occur in fibular hemimelia.
Diagnosis
Various investigative methods are available as part of the diagnosis of fibular hemimelia. Already in the womb, an existing malformation of the embryo can be detected by means of ultrasound examination. After birth, the curvature and shortening of the affected bones are obvious. The performance of X-ray examinations provides information about the extent of the malformation and additional changes in the bones. In any case, the diagnosis must be made clinically as well as radiographically. Differential diagnoses must also be performed in order to differentiate fibular hemimelia from various other disorders with sometimes similar symptoms. This is particularly relevant in view of the fact that each disease requires an individual therapy despite similar symptoms. In particular, the presence of thalidomide embryopathy, amniotic band syndrome, and various skeletal dysplasias with asymmetric involvement of lower limbs should be examined.
Complications
Severe deformities and malformations of the feet and thighs occur as a result of this disease. In most cases, these deformities also result in movement limitations and decreased aesthetics. Many patients also experience inferiority complexes and reduced self-esteem. These symptoms can sometimes lead to depression. In addition to the deformities of the skeleton and the feet, complaints of the heart and kidneys may also occur. In the worst case, these complaints can be fatal if kidney failure or heart failure occurs. In some cases, developmental disorders may also occur, resulting in decreased intelligence. The treatment itself does not lead to further complications and can reduce the symptoms of the disease relatively well. Surgical interventions are mainly used to bring the legs to the same length. Amputation may be necessary. Therapeutic measures are used if there are further complaints of coordination or movement. If the organs are spared from damage, life expectancy remains unchanged.
When should you see a doctor?
If abnormalities and malformations of the skeletal system are noticed during the birth of a child, a medical examination should be initiated immediately. Inpatient births are attended by a team of obstetricians who independently check the health of the infant. If the birth takes place without an obstetrician, a doctor should be consulted immediately afterwards. Bone structure inconsistencies in the calf or legs are considered worrisome. A doctor should be consulted as soon as palpable irregularities can be perceived in the feet, upper or lower leg. If the toe formation is visually conspicuous, a check-up should be initiated. If there are clearly recognizable deformities during the child’s growth and development process, a doctor should be consulted. If the child’s growth is significantly delayed compared to peers, especially in the area of the legs or feet, a check-up should be performed. If joint problems and irregularities occur, observations should be discussed with a physician. If the child experiences emotional or psychological problems in the course of life due to the visual abnormalities, a doctor or therapist should be consulted. If there is aggressive behavior, decreased self-esteem, or a strong tendency to withdraw, it is advisable for the child to seek therapeutic help. If serious psychological problems occur, in the form of an anxiety disorder or depression, the child needs professional help.
Treatment and therapy
Various measures are considered for the therapy of fibular hemimelia, depending on the individual case. In any case, treatment should be started as early as possible and, if possible, should take place in a pediatric orthopedic center. The spectrum of possible treatment methods ranges from orthoses and prostheses to so-called conversion osteotomies. In more severe cases, surgical leg lengthening or even amputation of the affected leg must also be considered. The weaker the fibular hemimelia is, the more a preservation of the leg with good functionality can be expected. Generally, therapy is done in conjunction with a multidisciplinary approach, with genetic counselors and pediatric orthopedic surgeons working together. Orthopedic treatment aims to compensate for the leg length discrepancy and to correct the asymmetric short stature in bilateral cases. In cases of only mild fibular hemimelia with a slight leg length discrepancy, therapy using orthopedic shoes and appropriate insoles is also used to compensate for the length discrepancy.
Outlook and prognosis
The outlook for recovery is very good in fibular hemimelia. If the condition is treated surgically or with medication immediately after birth, it can be relieved relatively quickly. However, the child will need support in the form of physical therapy. In some cases, such as when fibular hemimelia significantly limits mobility, an outpatient nurse must also be called in to help the child with everyday tasks. In principle, therefore, the prognosis is good, insofar as the patient receives the necessary treatment and later comprehensive support.The prognosis is worse if the condition is not detected in time or the therapy does not have the desired effect. In this case, permanent restrictions in the ability to move may remain. In addition, there may be insensitivity, nerve damage and other complications that significantly reduce the quality of life. Life expectancy is not limited by fibular hemimelia. As a result of the disease, the risk of circulatory disorders, thrombosis and other complications increases, which may be life-threatening. The physician can make a prognosis and suggest further measures after an initial examination and the start of therapy.
Prevention
Because fibular hemimelia is in all likelihood a hereditary condition, there are no known effective methods for preventing the malformation. Therefore, it is all the more significant to have specialist examinations when there are signs of the condition in order to positively influence the further course of fibular hemimelia.
Follow-up
Since this disease is a congenital disease, it is also not possible to perform a causal therapy in this case, but only a purely symptomatic therapy. A complete cure is also not possible in this case. If the patient wishes to have children, genetic counseling and testing can also be performed so that the disease is not inherited by the descendants. The earlier the disease is detected, the better is usually the further course. The treatment itself is primarily carried out by wearing prostheses. These should always be used if they can completely alleviate the symptoms. In severe cases, however, surgical interventions or even amputation are necessary to completely limit this disease. After such an operation, the affected person must usually always rest and take care of his body in any case. At the same time, strenuous activities or stressful activities must be refrained from in order not to slow down the healing process. Furthermore, in many cases, psychological support for the affected person is also useful. This can also be done by relatives or friends, and contact with other patients with this disease can also be useful. The life expectancy of the affected person remains unaffected by this disease.
This is what you can do yourself
If a newborn has been diagnosed with fibular hemimelia, treatment should be started as early as possible. In consultation with the doctor in charge at the maternity hospital, contact must be made promptly with a specialized clinic to provide the child with the best possible therapy. Orthopedists and specialists for the specific symptoms should also be involved promptly, as this is the only way to ensure a smooth therapy. Parents who have psychological problems as a result of the child’s illness are advised to consult a therapist. Under certain circumstances, participation in a self-help group may also be useful. The affected child may also need psychological care later in life. Depending on the severity of fibular hemimelia, the child may need crutches or a prosthesis. After an amputation, rest is indicated. The child will need to spend the first few weeks in the hospital and will require extensive support from parents at home. In some cases, an outpatient nursing service must be called in. Since dealing with an affected child is a considerable burden, all available assistance and support options should be utilized. Regardless of the severity of the malformation, close medical monitoring of the patient is necessary.
