Symposium on Common Orthopedic Problems

Diseases of the Developing Hip Joint Stanley Chung, M.D.*

Diseases of the pediatric hip must be diagnosed promptly so that the best available treatment can be instituted. Successful management can prevent damage to the joint and femoral head in many disorders, and obviate major hip reconstruction in adult life. This article discusses toxic synovitis, septic arthritis, Legg-Perthes disease, slipped femoral capital epiphysis, the snapping hip, and treatment of congenital hip disease in the newborn. Practical information for the pediatrician and family physician, such as methods of early diagnosis, differential diagnosis, how to avoid common pitfalls in diagnosis and management, treatment available, and results of treatment, is given. To evaluate hip disease a careful history and physical examination are essential. Even though the problem may seem confined to the hip, the entire child should be evaluated by an orthopedic and general medical examination so that no coexisting abnormality is overlooked. The orthopedic examination consists of the following: all the child's clothes except shorts are removed, and the stance or posture while standing is scrutinized. Leg lengths should be measured from anterior superior iliac spine to the medial malleolus. The circumference of each thigh two inches above the patella and of the calves at the fullest part is measured. A painful extremity may atrophy rapidly and will be detected by these measurements of circumference. If the child is able, he is asked to walk, run, squat, and stand on one leg at a time. The entire extremity is palpated, looking for points of tenderness and increased warmth. The skin is carefully inspected for bruises, ecchymoses, and puncture marks. Included in the search for the origin of disturbance is palpation of the abdomen and all body structures contiguous to the site of pain and examination of the feet, ankles, knees, and hips for complete active and passive range of motion. Hip flexion, internal rotation, external rotation, adduction, and abduction are recorded. Abduction should be tested in the frog position; flex both hips to 90 and then abduct. The distance in degrees at which the thigh stops from the table top is recorded. Abduction with the lower extremity flat on the table top is also recorded. 0

*Associate Professor of Orthopaedic Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania Pediatric Clinics of North America- Vol. 24, No.4, November 1977

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Information especially helpful is age, sex, race, history of trauma, presence of infection elsewhere in the body, height, weight, temperature, roentgenograms of the hip (in anteroposterior and frog position) and of hands and wrists for bone age, complete blood count and erythrocyte sedimentation rate.

TRANSIENT SYNOVITIS Transient synovitis of the hip, a self-limited unilateral condition, is the most common disease causing a limp in children. Only a few biopsies have been reported in this benign and transitory disease. These have revealed only nonspecific inflammatory congestion and hypertrophy of synovial membrane. Synonyms include toxic synovitis, "observation hip," irritable hip, transitory arthritis of the hip, serous coxitis, and coxitis simplex. Transient synovitis usually occurs in boys between 2 to 12 years of age (average 6 years). Many children have a recent history of a mild upper respiratory infection and may have elevated temperatures. The percentage of girls who develop transient synovitis is higher than that of girls who develop Legg-Calve-Perthes disease. The pain may be mild or occasionally severe enough to awaken the child at night. Pain may be absent entirely but all patients limp. Hip motion, especially internal rotation and abduction, is limited. There may be thigh atrophy, and the child may walk with the limb in slight flexion, abduction, and external rotation. Radiographs of the pelvis are usually normal; however, widening of the distance between the medial acetabulum and the ossified part of the femoral head occurs occasionally. Soft tissue capsular shadows lateral to the femoral head and neck are not consistently helpful in differentiating transient synovitis from normal appearances. The complete blood count and sedimentation rate are usually normal but the latter may be elevated.

Differential Diagnosis Diseases in the differential diagnosis include early Legg-Perthes disease, septic hip, early osteomyelitis of the proximal femur, acetabulum or sacroiliac joint, local trauma, post rubella immunization synovitis, pauciarticular arthritis, rheumatic fever, tuberculosis, osteoid osteoma, and slipped femoral capital epiphysis. When a child between 2 and 12 years of age presents with a limp, hip pain, and decreased motion, we have found the most helpful initial information for an accurate evaluation besides a complete history and physical examination is: the child's temperature, roentgenograms of the pelvis, anteroposterior and frog lateral, complete blood count and sedimentation rate, and radiographs of the hands and wrist for bone age. If the temperature and sedimentation rate are normal, consider transient synovitis, local trauma, Legg-Perthes disease, slipped epiphysis, and osteoid osteoma. If the child has an elevated temperature

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and sedimentation rate, septic hip, osteomyelitis, collagen disease, or occasionally the combination of local trauma and upper respiratory infection is considered. Bone age is helpful, since a delay of six months to three years is found in 90 per cent of children with Legg-Perthes disease. A rule of thumb is, normally, one carpal bone per year of age should be ossified. If both bone age and hip roentgenogram are normal, Legg-Perthes disease is unlikely. If a child has a low-grade fever, elevated sedimentation rate, and pain on hip motion, synovial fluid should be obtained by hip joint aspiration so that synovial analysis and bacterial culture may be performed. On rare occasions the initial symptoms of neuroblastoma may resemble transient synovitis. This condition is associated with persistent pain, malaise, abdominal masses or abdominal discomfort, and persistent elevation of sedimentation rate. A spot test (VMA- vanillyl mandelic acid) is a specific test for neuroblastoma. If this is positive a definitive work-up should be done. If pain persists on follow-up examination and routine radiographs remain normal, a technetium bone scan may prove helpful. A negative defect can be observed in the femoral head in early Legg-Perthes disease or an increased local uptake seen in osteoid osteoma or pelvic or proximal femur osteomyelitis. Black patients should undergo screening for sickle cell anemia.

Treatment Transient synovitis is generally a self-limited condition. Treatment directed toward relief of pain can be carried out on an outpatient basis and consists of bed rest for 7 to 10 days, local application of heat, massage of the hip area, and aspirin. Crutches may be used to gradually resume weight bearing. Patients with intractable pain, low-grade fever, and elevated sedimentation rate are hospitalized for observation to rule out septic hip or osteomyelitis. Either Buck's traction or split Russell's traction can be applied in the hospital. Transient synovitis may recur; the treatment program should be reinstituted and other diseases ruled out. Approximately 6 per cent of children with symptoms of transient synovitis eventually develop Legg-Perthes disease. Two long-term follow-up studies of patients with transient synovitis revealed on hip roentgenograms an increased incidence of wide femoral necks, deformed femoral heads, coxa magna, and osteoarthritic changes. This disease may not be as benign as once thought. 3,4

LEGG-CALVE-PERTHES DISEASE Legg-Calve-Perthes disease is an avascular necrosis of the femoral head involving otherwise clinically normal children. The disease may be divided into four stages: initial or bone and marrow necrosis, fragmentation or revascularization, reossification, and residual deformity (Fig. 1). Legg-Calve-Perthes disease is found in children between 4 to 8 years of age; the ratio of boys to girls is 4 to 5: 1. The annual incidence

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Figure 1. A, Anteroposterior view of pelvis in a seven year old girl with typical limp, pain, and decreased motion of Legg Perthes' disease. Note slight flattening, sclerosis of left capital femoral epiphysis. B, One and one half years after varus osteotomy, the head is reossified and the contour is good. The patient has returned to normal activity.

was estimated at 1:18,000 in Massachusetts during 1964 for children under 14 years. Typically Legg-Calve-Perthes disease is found in Caucasian boys; however Filipinos, Eskimos, Chinese, and Korean children are also affected. It is rarely diagnosed in black children. A low birth weight is found to be correlated with Legg-CalvePerthes disease; especially affected are baby boys weighing less than 5 1/2 pounds estimated to be five times more likely to develop Legg-CalvePerthes disease than those weighing 8 1/ 2 pounds or more. The bone age in Legg-Calve-Perthes disease is markedly retarded in 74 to 89 per cent of boys and 22 per cent of girls. Greater retardation is found in earlier stages of the disease and eventually normalization occurs. Brothers but not sisters of patients with Legg-Calve-Perthes disease have bone ages significantly below normal. Both boys and girls have a tendency to short stature. Interesting parallels exist between Legg-Calve-Perthes disease and constitutional delay of growth. Children with the latter condition are usually clinically normal Caucasian boys with retardation of growth and a delay of 2 to 4 years in bone age. The ratio of boys to girls is 10:1; the

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ratio of white to black children seeking consultation is 10: 1. Constitutional delay of growth may be familial. Legg-Calve-Perthes disease has been reported in monozygotic and dizygotic twins. Twenty per cent of cases are familial. The incidence of Legg-Calve-Perthes disease is 1 :35 in family members compared with 1 :20,000 in the general population. A limp, occasionally painless but usually accompanied by pain in the groin, lateral hip, or knee, is the first symptom. These symptoms may persist for 1 to 12 months before the parents seek medical advice. The patient may fatigue easily and stiffness is frequently present. A history of trauma may be present. The child with Legg-Calve-Perthes disease has an antalgic gait, an acute one-sided limp where the patient takes quick soft steps to shorten the period of weight bearing on the involved extremity. The range of hip motion is limited, especially internal rotation and abduction. A flexioncontracture may be present. Measurement of thigh and calf circumferences reveal atrophy on the affected side. Palpation often reveals tenderness over the anterior capsule. Later in the disease process the leg lengths may be decreased by 1f2 to 3/4 of an inch as the head becomes flatter. Legg-Calve-Perthes disease is usually unilateral but both hips are affected in 10 to 18 per cent of patients; two episodes in the same hip have been reported in 0.25 per cent of children who develop this condition.

Roentgenographic Findings The first radiographic change noted is widening of the distance between the ossified head and ossified acetabulum. The epiphyseal line becomes wider and the capital femoral epiphysis more radiopaque. As the disease continues, the femoral head collapses, the neck increases in width, and occasionally the head is displaced laterally or subluxates. The head becomes demineralized in the fragmentation or revascularization stage. Reossification of radiolucent portions of the femoral head and metaphysis gradually and finally completely occurs. Residual deformities include acetabular widening and flattening to accommodate the similarly flat and deformed head. The width of the neck is increased and the lateral margin of the deformed head may protrude outside of the acetabulum. In severe cases subluxation of the femoral head may occur and the top of the trochanter may become higher than the top of the flattened femoral head. Pressure caused by the head on the lateral edge of the acetabulum may cause degenerative changes such as loss of articular cartilage and osteophyte formation in middle age or later life. Bone Scans Bone imaging with 99mTc-polyphosphate may be helpful for differentiating early Legg-Calve-Perthes disease from transient synovitis, osteoid osteoma, low-grade osteomyelitis, and other conditions. The study is particularly useful in a child with a persistent painful limp and normal or questionable roentgenographic findings. In early Legg-Calve-Perthes disease before radiographic changes, the uptake is decreased in the capital femoral epiphysis. Increased up-

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take later occurs in the course of the disease. In transient synovitis a diffuse uptake occurs over the entire hip joint including the acetabulum, femoral head and neck, and epiphyseal plate. Treatment

A few young patients between 3 and 4 years of age never develop more than minimal epiphyseal involvement and recover with minimal or no treatment. A few investigators believed that no form of treatment affected the outcome of Legg-Calve-Perthes disease. This might be true for a few young children with minimal involvement but is not true for those with typical established disease. If untreated, these children develop progressive flattening of the femoral head and increasing pain, limp, and flexion-adduction contractures. Several conservative and surgical methods are available. The method chosen by the physician will depend on his experience and other factors such as clinical symptoms and physical findings, radiographic appearance of the femoral head, and ability of the parents to carry out recommended treatment. Methods of treatment currently include conservative bracing or casting, or surgery on either the proximal femur or acetabulum. Several braces have been designed, all using the principle that the femoral head is contained within the acetabulum when the lower limb is abducted. Two long leg plaster casts held apart by two sticks incorporated in the plaster can be used, but have the disadvantage of keeping the knees immobile and flattening the femoral condyles after treatment for more than six months. Conservative methods are frequently successful in preserving the round femoral head contour, but must be continued for the 2 to 4 year course of the disease. The advantage of operative treatment is the child's return to normal activities after 3 to 4 months. However, the risks include anesthesia, infection, and blood transfusion. The surgical methods are proximal femur varus osteotomy, innominate osteotomy and, occasionally, in severe cases, combination pelvic and proximal femur osteotomy. These surgical methods have been introduced in recent years but early results seem encouraging. Occasionally even after surgery, bracing must be used because the femoral head continues to collapse.

SEPTIC HIP Early diagnosis is important. Vigorous treatment soon after onset of symptoms prevents destruction of the femoral head and neck. Typical septic arthritis of the hip in infants and children can be recognized without difficulty (Fig. 2). The child is febrile, and the proximal thigh is swollen and lies in a position of flexion, abduction, and external rotation. The child cries when the limb is moved, white blood count and sedimentation rate are elevated, and a portal of entry such as skin abscess, otitis media, pneumonia, and paronychia is present. Occasionally a septic hip is overlooked because medical attention is diverted by other acute, life-threatening diseases which precede or ac-

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Figure 2. Anteroposterior view of pelvis in a six year old girl. The left hip was destroyed from a septic hip in infancy.

company it. There are a few common diagnostic pitfalls in septic arthritis of the hip. Diagnosis is difficult in the neonate because the usual signs and symptoms are frequently absent. Temperature and white blood count may be normal. Swelling of the thigh is present and the child will cry when the limb is moved. Vague symptoms may occur with neonatal septicemia such as failure to thrive, refusal to feed, regurgitation, cynosis during feeding, lethargy or irritability, and abdominal distention. s Roentgenograms show local soft tissue and capsular swelling and a slight lateral displacement of the proximal femur. The difficulty with interpretation of radiographs in the neonate is that the femoral head is not ossified and one must measure carefully the displacement of the medial metaphysis from the acetabulum. The diagnosis of septic hip may be missed at first in the child recently or currently being treated with antibiotics for a bacterial pneumonia, tonsillitis, or intestinal or skin infection, who then develops hip pain. The hip pain may be minimal and range of motion only slightly limited. Attenuated bacteria from an infected site may spread to the hip joint. The physician must be aware that hip joint sepsis can occur at the same time that antibiotics are being administered for infection elsewhere. Unilateral swelling of the thigh or leg in a febrile infant with discomfort on leg motion may indicate a ruptured septic hip with spread of pus into the thigh fascial planes. These findings must not be attributed to femoral vein thrombosis, a truly rare occurrence in infants. When the physician performs a diagnostic hip aspiration, the needle must be long enough to reach the joint. The use of a short 1" needle will give a misleading negative aspiration. In larger children and adolescents a 3" No. 18 spinal needle is best for aspiration. Cultivation of bacteria such as H. infiuenzae requires media containing X and V factors. Therefore only media such Levinthal and chocolate agar are suitable, and unless they are employed routinely in culture of septic joints, infection with this organism may be missed. This organism should be strongly suspected even if cultures are negative in patients under two years of age. A septic hip refers to an infection of the joint space and synovium;

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it is not synonymous with osteomyelitis of the proximal femur. Osteomyelitis is infection of the bone, which if untreated may later spread to the hip joint. Make this distinction carefully because osteomyelitis may be successfully treated conservatively with only intravenous antibiotics, whereas a septic hip must be treated with antibiotics and surgical drainage. The hip joint space is small compared with joints such as the knee. If not released, accumulating fluid and pus containing destructive enzymes rapidly raise the intra-articular pressure and permanently injure vessels and articular cartilage.

Mode of Entry Microorganisms can enter the hip joint by various means. They may be transported by the blood from a distant infection (skin or subcutaneous abscesses, otitis media, pharyngitis, pneumonia, and umbilical infections). In neonates infection may occur as a complication of exchange transfusions given through catheters inserted into the umbilical artery. Routine femoral venipuncture has also been associated with septic hip. The needle may be contaminated and pass through the vein into the joint.

Pathogenic Microorganisms In some patients bacteria cannot be isolated from the synovial fluid because pus inhibits bacterial growth. If patients have received antibiotics before joint fluid or blood cultures were performed, bacteria may be difficult to isolate. The organism may be cultured from the blood since bacteremia may accompany a septic hip. In newborns staphylococcus and gram-negative rods are commonly found. In children from 1 to 18 months of age H. influenzae is a frequent cause of septic hip. Streptococcus, gonococcus, and Salmonella can infect the hip, the latter more commonly in patients with sickle cell anemia.

Radiological Findings In the newborn early signs include soft tissue swelling and lateral and upward displacement of the femoral shaft. If untreated, subluxation, dislocation, and bone destruction of the femoral neck or acetabulum may result. Later, avascular necrosis of the femoral head, coxa vara, coxa magna, and loss of joint space are seen if treatment is not totally successful.

Differential Diagnosis The diagnosis of septic hip must be made quickly because of the serious consequences of delayed treatment. In neonates the early stages of septic hip could be mistaken for cellulitis, venous thrombosis, superficial abscesses, and sciatic nerve palsy. These processes may be ruled out by examination of aspirated joint fluid. Lower extremity (venous thrombosis) is common in adults but uncommon in children. The signs and symptoms of venous thrombosis are local tenderness and swelling of the calf and thigh, local warmth, palpable venous cord, and Homan's sign. We have seen a ruptured septic hip with resulting medial groin

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abscess and leg swelling diagnosed initially as femoral venous thrombosis. The following conditions should be ruled out in acutely ill older children: transient synovitis, retroperitoneal abscess, avascular necrosis, rheumatic fever, juvenile rheumatoid arthritis, and hip pain of sickle cell crisis. A complete general pediatric and orthopedic examination should be done. Initial tests include anteroposterior and frog roentgenograms of the pelvis, complete blood count, sedimentation rate, and in black patients a sickle cell preparation. If the patient is febrile and the sedimentation rate elevated, the hip should be aspirated. If the fluid is normal, a technetium bone scan may reveal osteomyelitis of the proximal femur or pelvis. Although there are some exceptions, patients with no fever, normal sedimentation rate, negative radiological findings, and no abdominal tenderness or masses, and mild to moderate hip pain are more likely to have transient synovitis or early avascular necrosis than septic hip, and aspiration of the joint is not necessary. Treatment Once a diagnosis of septic hip is made, treatment should be prompt. Aspiration may be used to decompress the joint initially, but arthrotomy is the only reliable way to maintain drainage. After pus has been aspirated from the joint, antibiotics should be administered intravenously and an arthrotomy performed under general anesthesia within six hours. Antibiotics alone cannot cure septic arthritis but must be combined with decompression. Antibiotics are selected on the basis of the patient's age and the results of synovial fluid analysis and a Gram stain of pus from the joint. After the organism is identified and its sensitivity established, the antibiotic may have to be changed.

SLIPPED CAPITAL FEMORAL EPIPHYSIS Slipped capital femoral epiphysis is a disease in which the anatomical relationship between the femoral head and neck changes by a disruption of the epiphyseal plate. This condition occurs only before the epiphyseal plate closure and may occur in two ways: (1) the sheer force on the epiphyseal plate quickly increases so that the femoral head suddenly gives way with a crack through the epiphyseal plate, or (2) a more gradual slip occurs when the abnormally high sheer force is exerted over a more extended period of time. A normal epiphyseal plate can separate if the applied load is too great, or normal forces can separate a weakened epiphyseal plate. Chronic slips account for 80 per cent of pa tients. Acute slips occur from severe trauma, such as automobile accidents, falls from great heights, battered child syndrome, or traumatic obstetrical maneuvers. Patients vary in age from newborn to nine years. Mild symptoms are present for a short time before the actual slip occurs. Minimal trauma may then cause an acute separation with pain so severe that the child cannot bear weight on the affected extremity.

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The femoral head is usually displaced posteriorly and medially as the disease progresses, and displacement superiorly and laterally over the femoral neck occurs. The annual incidence for high-risk age groups (10 to 17 years for males and 8 to 15 years for females) is 10.08 per 100,000 in Connecticut and 2.13 per 100,000 in New Mexico. 7 Slipped capital femoral epiphysis develops shortly before or during accelerated growth and the onset of puberty. The ratio of males to females affected is about 2 to 4: 1. Blacks appear to be more susceptible than whites. Symptoms are more likely to develop in the spring or summer than in the fall or winter, possibly because of increased physical activity, or coincident with the growth spurt occurring during the same period. Unilateral cases occur three times more frequently than bilateral. A simultaneous diagnosis of bilateral slipped capital femoral epiphysis is made only in about 10 per cent of patients. The left side is involved twice as often as the right in boys, whereas in girls both sides are equally affected. Many authors have observed that patients with slipped capital femoral epiphysis have "Frohlich's syndrome" or adiposogenital syndrome. However, Frohlich's syndrome, a specific rare condition impossible to diagnose before 19 or 20 years of age, is produced by lesions in the hypothalmus or trauma to adjacent structures, or by encephalitis. These two terms unfortunately have been used as catch-alls to describe obese boys whose apparent hypogenitalism is caused by folds of fat in the genital areas and are not restricte'd to patients with intracranial lesions. A smaller group of patients are said to be tall and thin or ectomorphic; however, there was no evidence in a study by Kelsey et al. 6 that tall, thin children are particularly susceptible. It was found by Sorensen10 that a combination .of obesity with slow skeletal maturation renders these children more susceptible since increased stress is exerted on a relatively wide epiphyseal plate for a longer than normal period before the adolescent growth spurt. Many authors attribute slipped capital femoral epiphysis to endocrine abnormalities, although actual documented cases are few. Razzano et al. 9 found levels of human growth hormone and testosterone in the serum and estrogens and 17-ketosteroids in the urine normal in five patients with slipped capital femoral epiphysis. There are a documented number of cases in patients with endocrine abnormalities, but this is unusual. Human endocrine disorders most commonly associated are hypopituitarism, either primary or secondary to intracranial tumors. Slipped capital femoral epiphysis also has been diagnosed in a man with true hypogonadism, a Klinefelter mosaic, and in three patients with Down's syndrome. It further has been associated with hypothyroidism, renal rickets, and human growth hormone therapy. Patients with the chronic form have hip pain localized to the groin, buttock, or lateral hip. Occasionally the child may have knee pain only from the hip. Pain may be absent, but a characteristic external rotation of the foot and limb is present. In many patients the pain has been present for many weeks or months before the correct diagnosis is made or before medical attention is sought. The results of treatment are better

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the sooner the condition is diagnosed. Erroneous diagnoses include muscle strain, Osgood-Schlatter disease, flat feet, and growing pains. In acute slips patients are unable to bear weight on the affected extremity and the pain develops suddenly. Approximately 88 per cent of patients are obese. We studied their family members which showed that 83 per cent of their mothers, 80 per cent of their fathers, 60 per cent of their brothers, and 37 per cent of their sisters were obese. The patient often walks with a limp; the foot on the involved side is externally rotated and there is slight shortening of the limb. Hip motion, especially internal rotation, abduction and flexion, is limited. When the hip is passively flexed, the femur abducts and externally rotates. Hip extension may be increased but pain and spasm may produce a flexioncontracture. The patient with acute slipping may not be able to bear weight on the affected extremity. Newborns who have a traumatic slipped epiphysis hold the leg very still to avoid any active movement (pseudoparalysis) and cry if the limb is moved. The proximal thigh may be swollen, shortened, and externally rotated. The injury may be confused with congenital dislocation of the hip, but hip arthrogram may clarify the diagnosis.

Radiological Signs Both an anteroposterior and frog leg roentgenogram of the pelvis on a 14 x 17 cassette should be taken when a slipped epiphysis is suspected. A mild slip sometimes cannot be seen on the anteroposterior view but is more obvious on the frog lateral (Figs. 3 and 4). The width of the epiphysis is increased and its margins irregular. Occasionally when the diagnosis is suspected from the clinical findings but plain roentgenograms are only suggestive, a technetium bone scan may show increased uptake at the involved epiphyseal plate. Differential Diagnosis Diseases such as transient synovitis, avascular necrosis of adolescence, osteochondritis dissecans, idiopathic chondrolysis, monarticular juvenile arthritis, and low-grade septic hip should be ruled out if roentgenograms do not show a typical slip. In late onset Legg-Perthes disease or slipped capital femoral epiphysis, the bone age may be delayed but is normal in transient synovitis. A technetium bone scan may show increased uptake in avascular necrosis or osteochondritis dissecans. In idiopathic chondrolysis and monoarticular juvenile rheumatoid arthritis the joint space may be narrow. In the latter condition the sedimentation rate may be elevated and other joints may be involved. Treatment The only reliable treatment is surgery. For those patients who refuse surgery, a short plaster boot applied to both legs with a cross bar or a hip spica has been used. While these methods are not as good as surgery, they may be better than no treatment at all.

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Figure 3. A, Pain and limp occurred in the right hip of a 17 year old obese boy who fell while playing hockey. There is deossification just below the right capital epiphyseal plate and the femoral head is slightly tilted. B, Frog leg lateral view. The mild right slipped capital femoral epiphysis is more apparent on this important view.

Further slipping may be prevented with the introduction of thin threaded wires across the epiphyseal plate or by an arthrotomy and the insertion of bone pegs across the slipping epiphysis. This treatment should be done soon after diagnosis since the more slipping that occurs,

Figure 4. Severe bilateral slipped capital femoral epiphysis in a 14 year old boy. The disease at this stage is far more difficult to correct.

j

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the worse the result. For moderate and severe slipped capital femoral epiphysis, corrective osteotomies can be done to return the femoral head to a more normal weight bearing position. A complication with or without treatment is chondrolysis, a thinning of articular cartilage. Although the thickness may return with time, parents should be warned that despite surgery, the child may need further treatment, such as hip fusion or total hip replacement in later life, because of stiffness or pain.

THE SNAPPING HIP In placing the patient's hip in the frog or abduction, flexion, external position there may be a snapping sound and sensation which can be repetitively elicited when manipulating the limb. This is not the sign of entry and exit of Ortalani and Barlow respectively. This snapping sensation is a painless and benign finding and probably represents either sliding of the fascia lata over the greater trochanter or sliding of the tendinous portion of the psoas over the hip capsule. It must be differentiated from the click or clunk and jerking of congenital dislocation or subluxation of the hip. When in doubt, an x-ray of the hips may help, but since roentgenograms sometimes are difficult to interpret in early life, repeat physical examination at 2 to 3 months intervals should be done.

TREATMENT OF CONGENITAL HIP DISEASE IN THE NEWBORN As soon as the diagnosis is made, treatment should be initiated. Spontaneous reduction and stabilization have been shown to occur, but are difficult to predict. For this reason all unstable hips should be treated with either a Frejka splint or Pavlik harness (Fig. 5). It is important in the reduction of congenital hip disease to minimize the application of excessive force and subsequent rigid immobilization, as avascu-

Figure 5. Left, Pavlik harness on a newborn. The hips are fully flexed, then fall out passively into abduction. Right, Frejka plastic splint is easy to apply, but mothers should gently keep the hips abducted when changing diapers.

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lar necrosis of the femoral head may result. We do not recommend application of a bilateral spica cast to hold reduction because avascular necrosis of the femoral head has been reported with this method. Although both Frejka splint and Pavlik harness have been used successfully in children up to six months of age, reduction and stabilization are more likely during the first two months of age before adaptive shortening of the hip adductors has occurred. The Frejka splint should be used for 21 to 22 hours per day and may be removed for diaper changes. Although there is some risk of displacement of the femoral head when the splint is removed, this less strict policy may decrease the risk of avascular necrosis by allowing more hip movement. This splint is effective in uncomplicated cases, easy to apply, and inexpensive. The time in the splint may be gradually decreased as the hip becomes stable. Splinting at night may have to be continued for one year or more until both capital femoral epiphyses are equal in size. The Pavlik harness is also useful in the treatment of congenital hip disease in the newborn. The thighs are flexed with the straps, and the hips then passively fallout into abduction, reducing the femoral heads. The harness permits active hip motion and only prevents the infant from fully extending the hip in an adducted position. This harness has two disadvantages: (1) some mothers, even after instruction, have. difficulty understanding the principle of the harness and have difficultyadjusting the straps, and (2) parents may complain that the infants' knees are getting stiff and seem uncomfortable since this joint is constantly flexed in the harness. To correct these problems, weekly outpatient visits may be necessary until physician and parents are confident all is going well. The harness can be removed twice a day so that the child may extend its knees.

REFERENCES 1. Chung. S. M. K.: Identifying the cause of limp in childhood. Clin. Pediat., 13:769-771, 1974. 2. Chung, S. M. K., and Poliis, R. E.: Diagnostic pitfalls in septic arthritis of the hip in infants and children. Clin. Pediat., 14:758-767, 1975. 3. Fernandez de Valderrama, J. A.: The "observation hip" syndrome and its late sequelae. J. Bone Joint Surg., 45B:462-470, 1963. 4. Holenstein, P.: Nachkontrollen bei der transitorischen synovitis des kinalichen Huft gelenke. Z. Orthop., 101 :392-397, 1966. 5. Kadkhoda, M., Chung, S. M. K., and Abdbonojo, F. 0.: Congenital dislocation of the hip. Diagnostic screening and treatment: a comparative study of two populations of infants and children. Clin. Pediat., 15:159-166,1976. 6. Kelsey, J. L., Acheson, R. M., and Keggi, K. J.: The body build of patients with slipped capital femoral epiphysis. Am. J. Dis. Child., 124:276-281, 1972. 7. Kelsey, J. L., Keggi, K. J., and Southwick, W.O.: The incidence and distribution of slipped capital femoral epiphysis in Connecticut and Southwestern United States. J. Bone Joint Surg., 52A:1203-1216, 1970. 8. Obletz, B. E.: Acute suppurative arthritis of the hip in the neonatal period. J. Bone Joint Surg., 42A :23-30, 1960. 9. Razzano, C. D., Nelson, C., and Eversman, J.: Growth hormone level in slipped capital femoral epiphysis. J. Bone Joint Surg., 54A:1224-1226, 1972. 10. Sorenson, K. H.: Slipped upper femoral epiphysis: Clinical study on aetiology. Acta Orthop. Scand., 99 :499-517, 1968. Children's Hospital of Philadelphia 34th and Civic Center Boulevard Philadelphia, Pennsylvania 19146

Diseases of the developing hip joint.

Symposium on Common Orthopedic Problems Diseases of the Developing Hip Joint Stanley Chung, M.D.* Diseases of the pediatric hip must be diagnosed pr...
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