Leana Bolon

Feet Concerns Explained

Structural Vs. Functional Leg Length Discrepancy

Overview

leg length discrepancy can be present from birth (congenital) or acquired (a result of an injury, infection or tumor). Some of the conditions that can cause limb problems in a child or young adult include congenital conditions present from birth. Osteogenesis imperfecta,. Bow legs. Knock knees. Neurofibromatosis. Arthritis. Infections of the bones and tumors. Injuries involving the growth center of the bone. There may also be deformities that are a result of the soft tissues and not the bones, such as with arthrogryposis and burns.Leg Length Discrepancy

Causes

Leg discrepancy can develop from a medical issue in any portion of the femur or tibia. One leg may lengthen, but leg shortening is much more common. Factors that can cause leg length discrepancy include inherited growth deficiencies. Infections. A bone infection can cause delayed growth in the affected limb. Injury. If your child breaks a leg, it may be shorter once it heals. This is most likely to happen if the fracture or break was complicated, an open fracture, or an injury that affected the growth plate near the end of the bone. Alternatively, a break can cause bones to grow faster after healing, making a leg longer. Tumors. Legg-Calve-Perthes disease. This is a condition that affects the ball (femoral head) of the hip joint. The femoral head may be friable and damage easily, sometimes leading to shortening of the thigh bone. Hemihypertrophy. In children with this condition, one side of the body grows more quickly than the other. Vascular malformations. These are abnormal clusters of veins and arteries that can form close to the bone and stimulate growth. Juvenile arthritis. Inflammation from arthritis can stimulate growth in the affected leg and cause discrepancy.

Symptoms

Faulty feet and ankle structure profoundly affect leg length and pelvic positioning. The most common asymmetrical foot position is the pronated foot. Sensory receptors embedded on the bottom of the foot alert the brain to the slightest weight shift. Since the brain is always trying to maintain pelvic balance, when presented with a long left leg, it attempts to adapt to the altered weight shift by dropping the left medial arch (shortening the long leg) and supinating the right arch to lengthen the short leg.1 Left unchecked, excessive foot pronation will internally rotate the left lower extremity, causing excessive strain to the lateral meniscus and medial collateral knee ligaments. Conversely, excessive supination tends to externally rotate the leg and thigh, creating opposite knee, hip and pelvic distortions.

Diagnosis

Leg length discrepancy may be diagnosed during infancy or later in childhood, depending on the cause. Conditions such as hemihypertrophy or hemiatrophy are often diagnosed following standard newborn or infant examinations by a pediatrician, or anatomical asymmetries may be noticed by a child's parents. For young children with hemihypertophy as the cause of their LLD, it is important that they receive an abdominal ultrasound of the kidneys to insure that Wilm's tumor, which can lead to hypertrophy in the leg on the same side, is not present. In older children, LLD is frequently first suspected due to the emergence of a progressive limp, warranting a referral to a pediatric orthopaedic surgeon. The standard workup for LLD is a thorough physical examination, including a series of measurements of the different portions of the lower extremities with the child in various positions, such as sitting and standing. The orthopaedic surgeon will observe the child while walking and performing other simple movements or tasks, such as stepping onto a block. In addition, a number of x-rays of the legs will be taken, so as to make a definitive diagnosis and to assist with identification of the possible etiology (cause) of LLD. Orthopaedic surgeons will compare x-rays of the two legs to the child's age, so as to assess his/her skeletal age and to obtain a baseline for the possibility of excessive growth rate as a cause. A growth chart, which compares leg length to skeletal age, is a simple but essential tool used over time to track the progress of the condition, both before and after treatment. Occasionally, a CT scan or MRI is required to further investigate suspected causes or to get more sophisticated radiological pictures of bone or soft tissue.

Non Surgical Treatment

The key to treatment of LLD in a child is to predict what the discrepancy is at maturity. If it is predicted to be less than 2 cm., no treatment is needed. Limb length discrepancies of up to 2 or 2.5 cm. can be compensated very well with a lift in the shoe. Beyond 2.5 cm., it becomes increasingly difficult to compensate with a left in the insole. Building up the shoe becomes uncosmetic and cumbersome, and some other way of compensating for the discrepancy becomes necessary. The treatment of LLD is long-term treatment, and involves the physician and patient?s family working together as a team. The family needs to weigh the various options available. If leg lengthening is decided on, the family needs to understand the commitment necessary to see it through. The treatment takes 6 months to a year for completion, and complications can happen. But when it works, the results are gratifying.

LLD Shoe Inserts

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Surgical Treatment

Surgeries for LLD are designed to do one of three general things ? shorten the long leg, stop or slow the growth of the longer or more rapidly growing leg, or lengthen the short leg. Stopping the growth of the longer leg is the most commonly utilized of the three approaches and involves an operation known as an epiphysiodesis , in which the growth plate of either the lower femur or upper tibia is visualized in the operating room using fluoroscopy (a type of real-time radiographic imaging) and ablated , which involves drilling into the region several times, such that the tissue is no longer capable of bone growth. Because the epiphyseal growth capabilities cannot be restored following the surgery, proper timing is crucial. Usually the operation is planned for the last 2 to 3 years of growth and has excellent results, with children leaving the hospital within a few days with good mobility. However, it is only appropriate for LLD of under 5cm.