Blount's disease or 'tibia vara,' is a growth disorder in the shin bone that affects the bones of the lower leg causing the lower leg to angle inward. This resembles a bow leg.
Named after the American orthopedic surgeon, Putnam Blount (1900 - 1992), Blount's disease is characterized by progressive lower limb deformity. Though Blount can affect people at any time during the growing process, it is more common in kids younger than four and in teens. A lot of pressure is put on the growth plate on the top of the tibia. This portion is called the physis - made out of cartilage, weaker than bone. The function of the physis is to allow the bone to lengthen and grow.
Due to excess pressure, the bone does not grow normally and instead the lateral outer side of the tibia keeps growing whereas the medial or inner side of the bone does not. Because of uneven bone growth, the tibia tends to bend outward instead of growing straight. Blount is not the same as naturally bowed legs that babies and toddlers have which usually straighten out when they start walking.
Blount is described as two distinct forms, early or infantile and late or adolescent Blount disease.
Infantile Blount disease is diagnosed between age one and three years. The disease presents when a child begins to ambulate. This disease is often bilateral and is less commonly associated with obesity.
Quite unlike the infantile Blount, late onset of Blount disease occurs in older children and is commonly associated with obesity and is often unilateral.
A combination of mechanical and biological factors influences Blount's disease to varying degrees. The mechanical forces contributing to the disease are weight of the child, age at walking, and varus deformity. The compressive forces across the medial femoral physis lead to growth retardation. Adolescent Blount does not appear to be progressive, or as common as the infantile form.
The cause of Blount disease remains controversial but it is mostly due to a combination of hereditary and developmental factors. There is increased incidence of the disease in overweight children who walk at an early age. Certain theories that mechanical overload of the proximal tibia contribute to Blount disease has been found. This mechanical overload is attributed to obesity and varus deformity. But this alone cannot be a cause as the disease is also noticed in children with normal weight.
Increasingly it is more common in people of African heritage, where kids start walking at an early age and whose family member might have had it. There is a genetic component to the disease as well, though a direct pattern of inheritance has not been clearly revealed. Hence, Blount is multifactorial and may differ in the early or late onset forms of the disease.
It is imperative to understand that Blount disease starts in early childhood or late teen years, the curve can get worse if not treated. Hence early diagnosis is important. The most obvious sign of Blount is bowing of the leg below the knee. While in young kids it is usually not painful, it teens it can be. It can feel like a growing pain in the knee area. The pain may come and go and many teens resort to over-the-counter pain relievers. As the lower leg bears the weight of the body, other problems such as rotation of the tibia are noticed. This causes a condition called in-toeing, wherein the feet point inward instead of straight out. Blount disease, over several years, can lead to arthritis of the knee joint and trouble walking. One leg may become slightly shorter than the other.
If there is knee pain that seems to be getting worse and cannot be traced to an injury, then the doctor might possibly consider Blount. A complete physical examination will be done, and X-rays of legs taken. The doctor will look for any abnormal growth pattern at the top of the tibia - a tell tale sign of Blount. This will help the doctor measure how severe the bowing is.
Treatment for Blount depends on the age of the patient and how far the disease has progressed. Young kids are advised braces, which are long-legged and lock the knee and need to be worn whilst weight bearing. But bracing is usually unsuccessful in girls and those with obesity. Older kids and teens will need surgery. There are different types of surgeries to correct Blount disease. These involve cutting the tibia, realigning it and holding it in place with plate and screws. This procedure is called Osteotomy. Sometimes, the damaged growth plate is removed and a device called external fixator is used to hold bones in place from the outside. In case of a twisted toe, surgeons correct the cause of it. Surgery is done under general anesthesia, and the patient might wear a cast and use crutches for a while. Physical therapy will be needed after surgery.
The smaller bone that runs parallel to the tibia on the outside of the lower leg is called fibula. Usually, fractures of the tibia and fibula occur simultaneously. If a person sustains only fibula fracture, it is because the side of the leg receives a direct blow, or it may be due to an extreme sideways bend at the ankle or knee. It may not cause any long-term complications, when there is a fracture of the fibula alone. If there is a fibula fracture alone:
The orthopedic will check for swelling, tenderness bruises, deformity and for any abrasions. Feeling the pulse along the length of the injured leg of the patient, the orthopedic will assess how one responds to touch. He will also check the normal muscle strength of the leg and the foot. This is to rule out any damage to the blood vessels or nerves by the sharp edge of the broken bone. To determine the blood flow to the leg accurately, the doctor might opt for specialized Doppler studies. To determine and confirm the location and the extent of severity of the fibula fracture, X-rays are conducted. Although some of the leg fractures take longer time to heal, normally the average healing time is six months.
By preventing accidents, many fractures can be avoided. Elders should encourage safe play among children. Careful driving and wearing seat belt will prevent fractures during driving. Osteoporosis is another condition that will result in fractures when a person falls.
The talus is a turtle-shaped small bone that sits between the heel bone calcaneus and the two bones of the lower leg, the tibia and fibula. Over half of the talus is covered with cartilage. The talus is an important connector between the foot and the leg and the body. It helps to transfer weight and pressure across the ankle joint. Therefore any injury to the talus affects the ankle and the subtalar joints and multiple planes of movement of the foot and ankle are also affected. It is interesting to note that the first series of talus fractures was described in men injured in the British Royal Air Force in early 1900, when the old war planes made crash landings. The term aviators astragalus was used to describe what we now call talus fracture. Typically causes for talus fracture include fall from heights, motor vehicle collisions and injuries of the lower back.
Persons suffering from talus fracture experience acute pain and considerable swelling and tenderness in the affected area. There is inability to bear weight. Often this type of fracture is mistaken for ankle sprain. A physician relies on x rays of the foot and the ankle to ascertain the nature and kind of talus injury. In some cases, if x ray does not reveal the nature of the fracture, a CT scan is requested. Fractures in the talus can occur:
Fractures of the talus are rare but when they occur they are highly complicated. Since talus has no muscle attachment and peculiar blood supply, high morbidity in the form of non-union and mal union can occur. Avascular necrosis, which means partial death of the bone, leading to a painful arthrosis condition is another common complication.
Immediate first aid has to be rendered to patients from talus fractures. A well-padded splint around the back of the foot and leg from the toe to the upper calf is placed. Foot must be elevated to the level of the heart to prevent further edema. Ice packs can be applied every twenty minutes till the physician arrives. Care should be taken not to put weight on the injured foot. Untreated talus fractures can create problems later. The foot may get impaired and the patient is at risk of developing arthritis and chronic pain. The bone may even collapse in certain cases.
Often talus fractures require surgery to minimize the complications from arising later. The surgeon realigns the bones surgically and uses metal screws to hold the pieces in place. Small fragments of bone can be removed by bone grafts which are used to restore the structural integrity of the joint.
Even after a good correction surgery, there is always the danger of deformity, arthritis and other conditions like lack of blood supply to the talus bones. The ability of the ankle to move can be affected if ankle arthritis occurs. Subtalar arthritis that is arthritis in the subtalar joint beneath the talus bone is another complication. Deformity of the foot is another problem of talus fracture. When the fracture is fixed, it becomes difficult to reposition the bone correctly and deformity may occur.
Bibliography / Reference
Collection of Pages - Last revised Date: September 18, 2018