FAQ Category: Child

Testing bone strength and stiffness outside of a laboratory can be a challenging task. Just as you are suggesting, to find out how much tension or force the bone can really handle requires applying enough pressure to actually break the bone. That breaking point is the maximum tensile strength of that bone.

When measuring bone stiffness, other factors come into the picture. The surrounding ligaments, muscles, and other soft tissues support the bone, too. The strength and interaction of these must be considered.

So it’s not really ethical to test a bone to and beyond the point of failure. But it is possible to test bone strength and progress in healing by calculating its stiffness. Enough force is applied to deform the bone within its elastic range.

A special device called Orthometer can be used. It is a commercially available goniometer-based system designed to measure the stiffness of healing fractures. A goniometer is a tool used to measure joint (and bone) angles.

This device is used under general anesthesia. It uses a three-point bending test and a microcomputer to calculate pressure applied to the bone. Bending angle and force can both be measured safely and accurately.

In a limb-lengthening operation, the short bone is cut and the two ends are distracted or pulled apart. The special external fixator device (cage) that you mentioned is used to distract the bone. The patient returns to the surgeon’s office at regular intervals and has the bone distracted many times.

Over time, as much as three inches can be added to the short leg. This does take time. Often the device is left in place for as long as 10 months. An average of 200 days (seven months) is more common.

Removing the fixator too soon can result in bone fracture and further leg deformity. Studies report a range of five to 40 per cent of fractures after fixator removal. Most of the fractures occur without any trauma or known cause. The bone just hasn’t regenerated enough to withstand the forces of everyday movement.

It’s possible that the fixator could be removed sooner. But caution is advised without objective measurements of bone stiffness or bone mineral density to guide the surgeon. Researchers are actively trying to determine reliable and accurate guidelines to use when making this decision. For now, time, X-ray results, and ultrasound give us a best-guess estimate of healing.

The Orthometer is a commercially available goniometer-based system designed to measure the stiffness of healing fractures. A goniometer is a tool used to measure joint (and bone) angles.

This device is used first at the time of the surgery while the child is under general anesthesia. It has a three-point bending test and a microcomputer to calculate pressure applied to the bone. Bending angle and force can both be measured safely and accurately. This gives the surgeon a reference value against which to compare future measurements.

Later, it can be used again externally. The cage is removed and clamps are attached to the pins still remaining. A special goniometer is attached to the clamps. Under a prescribed force or load, the amount of bend in the bone is measured by the goniometer.

Any changes in the front-to-back and side-to-side bone angle is recorded. This is a measure of bone stiffness. Measuring bone stiffness during the healing process shows how the healing process is going.

But using the Orthometer externally when the child is awake doesn’t always go as smoothly as during surgery. The child may be anxious and/or experience pain. Muscle spasm can occur making measurements difficult. The DXA scan is a painless and short procedure. She should have no difficulty with it.

Studies done by orthopedic surgeons show that more than half of shoulder and back pain reports in children is caused by heavy backpacks. Some of this is related to the way the backpack is worn — either low over the buttocks or slung over one shoulder.

The distribution of load has a direct effect on the pressure over shoulders and back. Uneven or excessive loads can create enough pressure to actually cut off blood flow to the skin under the straps.

Postural changes occur even when backpacks are worn evenly on both shoulders. For example, children commonly raise the right shoulder up when wearing a backpack. This movement is even more exaggerated when the pack is only worn over the right shoulder. It’s possible that with chronic use of a backpack over one shoulder (usually the right), the shoulder responds with the same movement pattern even when the pack is worn over both shoulders.

Back pain has been reported more often among children who wear a backpack with one strap instead of both straps. If the pack is worn low enough, then the weight is supported by the low back and/or buttocks. It is suspected that this pattern may be part of the problem leading to back pain in younger children.

Heelys are shoes for children that have rolling wheels in the heels. They were first sold on the market during the 2000 Christmas season. They quickly caught on in the United States and even around the world. More than 4.5 million pairs have been sold in 60 different countries.

The shoe glides along on wheels when the child lifts the toes up. This leaves just the heels in contact with the floor or ground surface. One foot is slightly in front of the other foot. Each shoe may have single or double wheels. The activity is called heeling.

The incidence of injuries from heeling is quite small compared to other activities such as basketball, football, or soccer. Forward falls onto an outstretched hand can cause fractures of the shoulder, forearm, or wrist. That’s one danger.

But there’s another danger — and that’s to the pocketbook. The associated costs can be quite large even with a simple fracture. Total cost of care adds up with the charge for the emergency department visit, X-rays, cast application, follow-up X-rays, and any cast changes needed over time. If surgery were needed, that could drive the cost up even more.

Accidents are going to happen in active children. Heelys don’t really put a child at greater risk of injury than other commonly enjoyed games and sports. However, safety is still a concern. Safety gear is always advised. Helmets can prevent head injuries. Protective pads for wrists, elbows, and knees may reduce the risk of arm or leg fractures. It’s a simple and fairly inexpensive way to protect your child.

Heelys are shoes for children that have rolling wheels in the heels. The child lifts the toes up and glides along on the heels. One foot is slightly in front of the other foot. Each shoe may have one or two wheels. The activity is called heeling.

Heeling seems like a fairly simple activity. The child stops by shifting the body weight to the front of the shoe. The wheels stop turning and the child can resume walking. But like all play equipment, problems can occur.

According to a study at a large city hospital, forward falls outdoors onto an outstretched hand are most common. Rocks stuck under the wheels can cause falls. Cracks in the road or sidewalk also throw children off balance. Inexperience (using Heelys less than one week) can be a factor. But even kids who have worn Heelys for more than one year injure themselves in falls.

It is highly recommended that children using heelys should be supervised and wear protective gear at all times. This includes helmet, forearm and kneepads, and gloves with wrist padding. More effort should be made to alert parents to the safety hazards of these shoes.

Bacteria, viruses, and fungi are all capable of infecting a joint. These tiny organisms invade and inflame the synovial membrane of the joint. Joint destruction with arthritis may be a local response to this infection. This condition is referred to as bacterial, infectious or septic arthritis.

As you have found out, acute septic arthritis in children can be present at birth. Early treatment is advised to prevent complications. In fact, a delay in diagnosis or treatment can lead to severe destruction of the hip joint.

The growth plate can be affected leaving the child with loss of motion. A difference in leg-length from side to side can occur. The combination of all these changes may mean the child will walk with a limp.

Studies show that a delay of four days or more increases the risk of a poor outcome. There are many other factors involved. Prematurity, type of bacteria, and the need for intensive care can affect prognosis, too.

The surgeon will use pelvic X-rays to judge the development of the hip joint. If the child is walking, the X-rays may be taken in the standing position. The surgeon looks for coverage of the femoral head by the acetabulum (hip socket). This means the round head at the top of the femur (thigh bone) is covered by the cup-shaped hip socket.

There are several measurements that can be taken from the X-rays that can help with this decision. For example, the acetabular cartilaginous angle (ACA) is a system of lines drawn on an x-ray to judge the formation of the cartilaginous portion of the acetabulum.

It includes a horizontal line along the bottom of the acetabulum. This is the Hilgenreiner line. Where the Hilgenreiner line intersects a second line determines the angle. The location of the second line differs according to the type of hip deformity that’s present.

Studies show that if the acetabular cartilaginous angle is less than 20 degrees, then the hip is very likely to develop fully. There is no further need for surgical repair. Patients with an angle greater than 24 degrees very likely need surgical correction. The procedure is called an acetabuloplasty. In this operation, the surgeon uses a bone graft (a piece of bone taken from the child or from a bone bank) to build out the edge of the hip socket. This helps enlarge the hip socket and keeps the head of the femur firmly in the socket.

Another measurement taken from the X-rays is the acetabular index (AI). The AI is formed by drawing a horizontal line at the bottom of the pelvis and an angled line from the bottom of the pelvis to the outer edge of the socket.

A normal child will have an index of 30 degrees or less. The index decreases until it reaches 20 degrees or less. This usually occurs by age four months. An acetabular index above 30 degrees is a sign to begin treatment. The higher the index, the more aggressive the treatment.

It’s important that you take your child to all of the scheduled follow-up appointments. The surgeon uses the ACA and the AI to help determine the success of the treatment. If further surgery is needed, early treatment has a better result.

Developmental dysplasia of the hip (DDH), also known as acetabular dysplasia (AD) is a common disorder affecting infants and young children. In this condition, the head of the femur slips out of a very shallow acetabulum (hip socket).

In mild cases called unstable hip dysplasia, the hip is in the joint but easily dislocated. More involved cases are partially dislocated or completely dislocated. A partial dislocation is called subluxation.

No one knows for sure why acetabular dysplasia persists despite early and aggressive treatment. It’s possible there are some genetic factors involved. Some children may grow bone faster than others. They are more likely to have a successful result.

When the hip is realigned at a young age, it’s difficult to predict whether or not the hip socket will deepen and form around the femoral head. Surgeons and parents often go through an anxious wait-and-see process.

Researchers are finding more accurate and reliable ways to get around this problem. New ways to predict success of a closed reduction for developmental dysplasia of the hip are now available. Closed reduction means the dislocated hip is realigned in the socket under anesthesia. It’s held in place with a cast. An open incision isn’t needed to accomplish this realignment.

Concerns about heavy backpacks for children have been in the news for several years now. Heavy loads can lead to shoulder and back pain at an early age. Children do not want to be singled out or different in any way.

So instead of nagging kids about their habits, some parents are approaching teachers about changing homework assignments and at-home book requirements. Computers are making it possible to do more research at home without taking heavy library books home. Posting worksheets and reading assignments on-line is also helping.

But when it’s absolutely necessary to wear a heavy backpack, there are a few guidelines that might help prevent pain and injury. First, make sure the backpack is well constructed. Strong, wide straps with padding are important. Adjust the straps evenly and place the pack high on the back. The closer the load is to the body, the better.

Everyone of all ages wearing a backpack should use both shoulder straps at all times. This means even for short distances. Studies show that after as little as 25 seconds, blood flow to the skin under the straps is cut off.

For younger children, insist that they empty out their backpacks at least once a week. It’s very easy to start to gather more and more things that aren’t truly needed in the backpack. This may help cut the load in the backpack and on the back.

Legg-Perthes Disease (Legg-Calvé-Perthes Disease) is caused by the loss of blood flow to the femoral head. Without adequate blood flow, the bone begins to die. There is a deterioration or flattening of the femoral head and neck. It can destroy the hip joint. It is not known what causes the disease. It could be caused by trauma.

Genetics and heredity may be a factor but do not appear to be the determining factor in the development of Legg-Perthes disease. It is possible that chromosomal mutations may play a part but this hasn’t been proven yet. When heredity is a factor, Perthes usually affects the male line.

Scientists are also looking at endocrine, nutritional, and socioeconomic factors that may contribute to the development of this condition. Recent research has identified cellular changes in the resting chondrocytes (cartilage cells). An increase in lipid (fat) cell formation may be a link in the process of cartilage degeneration that occurs. The exact meaning of this discovery isn’t known yet. More studies are needed to uncover the cellular changes and process that occur with Perthes disease.

Osteonecrosis means death of the bone tissue. When caused by a loss of blood supply to the area, it is also known as avascular necrosis. Perthes disease is an entity all its own but it is a type of osteonecrosis. A loss of blood or vascularization to the head of the femur (thigh bone) can cause the bone to start to die and collapse.

It is usually a self-limiting disorder. This means that the blood supply will return and the bone will repair itself. This is different from other types of osteonecrosis where bone destruction doesn’t stop or repair itself.

With Legg-Perthes disease, changes occur in the shape of the femoral head and the acetabulum (hip socket). This takes place during the process of developing and healing in this condition. This may lead to degenerative arthritis young in adult life.

With osteonecrosis, the dead or dying tissue has to be removed. Sometimes the bone is replaced with bone from a bone bank. In some conditions, the bone is replaced with a rolled up tendon graft. With Perthes disease, healing can occur without removing the bone and even without surgery.

Slipped capital femoral epiphysis (SCFE) affects the hip joint in some children and teens. The growth plate separates from the main bone at the top of the femur (thigh bone). The round head of the femur stays in the acetabulum (hip socket) while the neck and shaft of the femur slip up and away from the head.

SCFE may affect both hips. In fact, 20 to 40 percent of the time the condition is bilateral. Bilateral means it affects both hips. Only one hip may be painful, so it is common for doctors to carefully watch the other hip to recognize the disease as early as possible. The earlier the diagnosis is made, the more effective the treatment.

A recent study of the biomechanics of SCFE has shed some new light on the bilateral development of SCFE. It seems the angle and geometry of the hip that slips is very similar to the hip that doesn’t slip. The shear stress on the joint combined with the inclined angle of the epiphyseal growth plate may be risk factors for SCFE.

Many of the children with SCFE are overweight or even medically obese. The added weight increases the shear stress even more. When the stresses on the hips of children with normal hips are compared to children with SCFE, there is a higher average shear stress among the children with SCFE. This is true even when the body weight is factored into the analysis.

What we don’t know yet is how to predict who might develop SCFE on the second side. More studies are needed to find those predictive risk factors.

Slipped capital femoral epiphysis (SCFE) is a disease of the hip in older children and young teens. During a period of rapid adolescent growth, the growth plate separates from the femoral neck (upper portion of the thigh bone). The growth center of the hip (the capital femoral epiphysis) actually slips backwards on the top of the femur (the thighbone).

There may be many factors contributing to the development of SCFE. These include genetic, endocrine, and mechanical risk factors. The exact mechanism by which the condition develops isn’t fully understood.

Children who are overweight are more prone to developing SCFE. This suggests that the main cause of SCFE is from increased force on the hip at a time when the femoral head is not quite ready to support these forces. The femoral head fails at the weakest point, through the epiphyseal plate. As a result, a condition similar to a stress fracture develops.

Septic (infectious) sacroiliitis can occur in young children as a result of a staph infection that has traveled via the blood to the sacroiliac joint and infected it. The condition is rare accounting for only 1.5 per cent of all pediatric cases of septic arthritis.

The diagnosis can be difficult to make. The physician uses clinical symptoms, lab findings, and imaging studies to determine the cause of the symptoms. And the symptoms can vary from back pain to knee pain to buttock pain with or without a limp when walking. There may be a fever, chills, or other similar symptoms.

Other equally rare disorders that can mimic septic arthritis include bone tumor or blood disease. Joint aspiration is one way to test and diagnose septic sacroiliitis. But it can be a painful and unpleasant procedure for the child. MRI may be a much better choice. The detail on the MRI is enough to tell the difference between sacroiliitis and a muscle abscess.

Intravenous drug use/abuse is one cause of septic sacroiliitis in the adult population. Other risk factors for adults include trauma and pregnancy. The most common cause in both age groups is infections of other systems such as an ear or bladder infection.

Septic sacroiliitis is an infection of the sacroiliac (SI) joint. There is an SI joint located to the right and left of the sacrum where the pelvic bones meet the sacral bone. The condition is very rare and difficult to diagnose.

As in the case of your daughter, the pain can present at a joint other than the one affected. Back, buttock, hip, SI, and knee pain are all possible with this condition. Having already treated your child with an antibiotic (and possibly seeing the inner ears were clear), the physician likely assumed the problem was resolved.

And it’s true that the ear infection was cleared up. However, the infectious agent traveled along the blood stream to this distant site and set up housekeeping there. Symptoms of pain and limping without obvious changes in the joint (redness, swelling, heat) make it easy to dismiss the problem.

Most cases of septic sacroiliitis in children are, in fact, misdiagnosed. The most common false diagnoses given are arthritis, disc herniation, or tumor. In many cases, it isn’t until the condition gets worse and an emergency visit is needed that the diagnosis is finally made.

Paralysis of the hand present at birth may resolve completely with time. It depends on the cause of the problem and the extent of the nerve involvement. Brachial nerve palsy is the most common cause of arm and hand paralysis at birth.

The brachial nerve plexus is the group of nerves that leave the neck and travel down the arm. Pressure on the nerve complex while in the womb or stretching of the nerve during delivery can cause this problem. The entire upper extremity can be affected.

Forceps delivery can also causes upper plexus lesions leading to a condition called Erb’s Palsy. A child with this type of injury holds the arm and hand in a position called the waiter’s tip deformity. The forearm is held next to the body and rotated with the wrist bent so much it looks like the child is asking for money or a tip.

Recovery from a brachial plexus injury can occur with time. Physical and/or occupational therapy may be recommended. The therapist may place the child in a protective splint. The splint is meant to prevent permanent loss of joint motion. The child is encouraged to do exercises and activities to help maintain motion until recovery occurs.

And finally, there is the isolated radial nerve palsy. Pressure on the radial nerve causes palsy of the wrist and hand (but not the shoulder or upper arm). This is rare and usually reported linked with long labors (more than 18 hours). Recovery is complete in all cases published in the medical journals.

Fetal inactivity in utero (in the womb) can lead to pressure on the nerve. The result can be a nerve palsy. But prolonged labor and the use of forceps during delivery can also contribute to nerve damage and paralysis.

It’s even possible for this condition to occur after birth. The use of a blood pressure cuff to monitor vital signs can also cause nerve palsy. Doctors can’t always be sure whether the injury occurred before, during, or after birth.

Congenital (present in utero) problems with nerve palsy can occur. These are usually associated with other problems or conditions. The physician is careful to look for infection, shoulder or elbow dislocation, and bone fracture. Sometimes there are constricting bands of fibrous tissue around nerves that can cause nerve palsy.

It may take some time to sort out all the possible causes. A “wait-and-see” approach works well at first. Given time, the clinical picture may become clearer. Many times the problem goes away on its own.

The goal of treatment is to avoid preserve the bone mass, shape, and function until the disease runs its full course. Modern treatment with pressure reduction on the joint along with physical therapy to maintain joint motion, strength, and function is effective for many children.

Doing specific exercises during the healing process ensures that the femur and hip socket are smooth and glide smoothly. The program minimizes the long-term effects of the disease.

Treatment also focuses on activity modification (no extreme or running sports) and using crutches to offload the joint. Orthoses (braces) to properly position the hip and help relieve the joint of the body’s weight may be needed. This gives the top of the femur room to regrow and shape better. In some cases, surgery is recommended.

Currently, there are studies conducted on medications to prevent bone resorption for the treatment of Perthes. Pain relievers may be given as needed. Close management and follow-up with an orthopedic surgeon is crucial. Younger children have a better prognosis than older children.

Perthes is a long-term problem. There’s no cure but the damaging effects of the disease can be minimized. As these children age, problems in the knee and back can develop. The acetabulum (hip socket) can develop an abnormal shape and angle. Osteoarthritis is very common because of the uneven wear in the damaged hip. Adults over the age of 50 with a history of Perthes disease have a higher incidence of hip joint replacement compared with adults the same age who did not have Perthes.

With continued studies and new knowledge gained, treatment results may improve. Children born with this disease today will have a much better outcome than even 10 years ago.

With so many more children participating in sports, the chances of serious injuries are bound to go up. It’s estimated that 30 million kids are active in organized sports program in the United States. Studies show there are 20 million injuries per year among this group.

There’s no doubt that proper nutrition and adequate hydration are two key factors in injury prevention. But other factors come into play as well. Bone fractures are more common in younger children who have softer and more porous bones. They do seem like they are made of “rubber.” This is because their tendons and ligaments are stronger than their bones. The soft tissue structures covering and connecting the bones offers a strong protective barrier to injury.

The improper use of protective gear (or not wearing protective gear at all) may also contribute to the rise in sports injuries. The cost of such equipment can seem prohibitive until we look at the cost of visits to the emergency department (1.8 billion dollars each year).

Groups like the American College of Sports Medicine, American Medical Society for Sports Medicine, and the American Osteopathic Academy of Sports Medicine are actively looking for ways to help prevent pediatric sports-related injuries. One-fourth of those injuries are bone fractures. They are taking all factors into account, including diet and nutrition. We expect to hear more about this as further evidence comes to light.