CLINICAL FEATURES

There are no symptoms in the newborn, but most cases are detectable at birth. The clinical picture of the unstable hip will range from minimal findings to obvious frank dislocation, depending on the age of the child. In the newborn, provocative maneuvers, such as Barlow’s and Ortolani’s tests, are commonly used to detect instability. The tests are similar. The Ortolani test refers to the gentle reduction of the dislocated hip by abduction of the flexed hip (Fig. 10-5). This is often accompanied by a soft “clunk,” sometimes called the click of entry. In Barlow’s test, the hip is purposely dislocated by gentle downward pressure of the flexed, adducted hip. With posterior pressure, the femoral head will be displaced out of the acetabulum if the hip is unstable, sometimes called the click of exit. The head is then reduced by gentle abduction of the flexed hip by performing Ortolani’s maneuver. Barlow’s test should not be performed excessively, because it could make the problem worse. Occasionally, this maneuver may result only in a sensation of excessive gliding without an obvious dislocation. This may be an indicator that the hip is subluxable and therefore unstable. Soft clicks sometimes felt during abduction–adduction movements are not considered pathologic unless other findings are present.

Fig. 10-5 Ortolani’s sign for congenital dislocation of the hip. A “click” is palpable or audible as the hip is reduced by abduction. If the test is negative, the examination should always be repeated in 2 to 4 months.

If the diagnosis is made late, the hip is less flexible, and the ability to reduce the dislocated hip by the provocative maneuvers is lessened. At this time, the physical findings may include asymmetry of the skin folds and limited abduction (Fig. 10-6). If the hip is dislocated, it may not be reducible, and other signs may be present, such as shortening of the extremity (Fig. 10-7).

Fig. 10-6 Restricted abduction of the right hip.

Fig. 10-7 Galeazzi’s or Allis’ sign. The child is placed on a firm surface with the hips and knees flexed. The knee will appear lower on the dislocated side.

If weight bearing has begun, a painless limp is often the initial symptom of dislocation. Hip motion, especially abduction, is limited, and abnormal piston mobility or “telescoping” may be present. The Trendelenburg test is usually positive. This test takes advantage of the fact that normally, when standing on one leg, contraction of the abductor muscles on the side bearing weight will cause the opposite side of the pelvis to be elevated. If the hip is dislocated, these muscles no longer work effectively, and when the child stands on the affected leg, the opposite side of the pelvis drops downward instead. This causes the typical waddling gait caused by abductor weakness.

The roentgenographic examination is usually not very helpful when the patient is younger than 3 months of age unless a complete dislocation is present. After this age, a delay in the ossification of the femoral head is frequently noted (Fig. 10-8). The acetabulum may be more inclined vertically, and the acetabular index is often increased. If subluxation or dislocation has occurred, upward and outward displacement of the femoral head will be seen.

Fig. 10-8 Roentgenogram of the pelvis. P, Perkin’s vertical line; H, Hilgenreiner’s horizontal line; AI, acetabular index. The ossification center of the capital femoral epiphysis should lie in the inferior medial quadrant formed by Perkin’s and Hilgenreiner’s lines. The AI normally measures less than 30 degrees. Here, ossification of the capital epiphysis on the dysplastic hip (arrow) has been delayed as compared with the left.

Ultrasonography is useful in congenital hip dysplasia, especially in high-risk infants (such as those who are breech delivered or who have a positive family history) or those with uncertain clinical findings. Among its benefits is the elimination of exposure to radiation. Magnetic resonance imaging (MRI) may eventually be helpful, but the diagnosis can usually be established by other means.

TREATMENT

Referral is indicated if there is any suggestion of instability in the hip of the newborn. Treatment is initiated as soon as possible and varies with the age of the patient and the degree of dysplasia. Early detection is of utmost importance, because conservative treatment is more likely to succeed in the infant. The more the child’s age exceeds the weight-bearing age, the more likely it is that surgery will be necessary, and the less likely that a normal functional result will ensue. Whenever any doubt exists, treatment and follow-up are indicated.

The objective of treatment is to reduce the femoral head into the acetabulum and maintain that reduction. By maintaining the hip in the reduced position, normal development of the hip joint structures and deepening of the acetabulum are encouraged. A variety of external devices are available for the treatment of hip dysplasia or dislocation, the most functional of which is the Pavlik harness (Fig. 10-9). The brace is usually worn for several weeks until the hip is stable.

Fig. 10-9 The Pavlik harness.

Failure to obtain or maintain a stable reduction necessitates surgical intervention. The objective is to reduce the hip by either closed or open methods and maintain the reduction by casting or osteotomy.

CLINICAL FEATURES

The onset is gradual, and the initial complaint is usually a mildly painful limp. The pain is often referred down the inner aspect of the thigh to the knee (via the obturator nerve). The discomfort is frequently relieved by rest and aggravated by weight bearing. Examination reveals moderate restriction of motion secondary to the synovitis. Abduction and internal rotation are especially limited. Pain is present at the extremes of motion, and tenderness is usually noted over the anterior hip joint.

Plain roentgenograms are usually abnormal, but MRI or bone scanning may be helpful in equivocal cases.

TREATMENT AND PROGNOSIS

Referral is indicated whenever the diagnosis is suspected. Treatment recommendations continue to evolve. The ultimate goal of treatment is to prevent deformity of the femoral head while healing is progressing. If a deformity can be prevented, the chances of degenerative joint disease developing at a later date are lessened. The initial goals of treatment are the relief of pain and maintenance of joint motion, which are accomplished by rest to control synovitis. Many children younger than 6 years of age with minimal involvement have a good prognosis and require only symptomatic care. The older child who is at risk for having a poor outcome may require treatment. In these children, treatment is aimed at keeping the femoral head centered in the acetabulum. If the head is contained in the acetabulum while it is re-forming, the acetabulum will “mold” the head and prevent significant deformity from occurring. These goals of treatment are usually accomplished by the use of an abduction brace that allows motion but contains the head in the acetabulum (Fig. 10-11). The brace must be worn continuously for up to 2 years, although the results of specific forms of treatment remain inconclusive, and some investigators advocate only nighttime bracing. Surgery may be necessary in select cases.

Fig. 10-11 Abduction brace for Perthes’ disease.

The prognosis depends on the age of the patient, the degree of involvement, and the adequacy of treatment. Young patients with minimal involvement who are treated early do very well with few sequelae. Patients over 8 years of age frequently have some permanent restriction of motion, a slight limp, and a more irregular or flattened femoral head. A few patients will later develop degenerative arthritis.

CLINICAL FEATURES

The onset is generally gradual, and symptoms usually occur even when little displacement is present. Mild discomfort in the hip, groin, and knee and a painful limp with activity are the most common initial complaints. Symptoms have often been present for several weeks. Examination reveals tenderness over the hip joint capsule. An external rotation (toeing-out) deformity of the lower extremity may be present, and internal rotation, abduction, and flexion are usually restricted. Pain is present at the extremes of motion, and the hip tends to rotate externally and abduct as it is flexed (Whitman’s sign).

In the early “preslipping” stage, the roentgenogram characteristically reveals irregular widening of the epiphyseal plate and joint swelling (Fig. 10-12). As displacement occurs, a line drawn along the superior or anterior neck of the femur will transect less of the femoral head than normal. This may be more readily seen on the lateral view. More severe degrees of slippage are usually easily diagnosed.

Fig. 10-12 Slipped capital femoral epiphysis. A, Widening of the epiphyseal plate on the right side (arrow) and B, displacement of the femoral head are present. Displacement is best seen on the lateral view.

A condition similar to slipped capital femoral epiphysis is termed acute traumatic separation of the upper femoral epiphysis (Fig. 10-13). This is actually an epiphyseal fracture and has a much poorer prognosis than the gradual slippage that occurs in slipped capital femoral epiphysis.

Fig. 10-13 Acute traumatic separation of the upper femoral epiphysis.

TREATMENT

As soon as the diagnosis is made, a referral for surgery is indicated. The patient is immediately placed on crutches, and weight bearing is prohibited. Traction in the hospital may be necessary to reduce the acute component of the slippage. To prevent further slippage from occurring, the femoral head is fixed to the neck, generally by using small pins (Fig. 10-14). Weight bearing is prohibited for several months until the epiphyseal plate closes. Severe deformities may also require osteotomy of the femur.

Fig. 10-14 Postoperative roentgenogram following pinning for slipped capital femoral epiphysis.

The prognosis is usually good, except in those cases with acute traumatic separation. The chronic form may result in slight shortening of less than 1.25 cm along with a mild external rotation deformity. In cases with acute traumatic separation, avascular necrosis of the femoral head is a common complication, and this usually results in severe traumatic arthritis of the hip (Fig. 10-15). The more common chronic slippage does not usually cause avascular necrosis.

Fig. 10-15 Avascular necrosis and osteoarthritis following acute traumatic slipped capital femoral epiphysis. Reconstructive surgery was eventually required.

CLINICAL FEATURES

The onset is frequently acute and may follow a traumatic event or a recent upper respiratory tract infection. A painful limp is characteristic, and the pain is frequently referred to the inner aspect of the thigh and knee joint. A few patients have night pain. The hip is typically held in a position of slight flexion, abduction, and external rotation so that the hip joint capsule is under the least amount of tension. Pressure and discomfort are thereby reduced. Passive motions, especially internal rotation and abduction, are restricted. Temperatures of 37.3°C to 38.3°C may be present.

The roentgenograms may reveal swelling of the capsule and adjacent soft tissue but are usually normal. Slight widening of the joint space may be present, but there are no changes in bone texture. Ultrasonography may help determine the presence of excessive joint fluid.

Laboratory findings are usually minimal, although there may be a slight increase in the white blood cell count. Aspiration and culture of the hip joint fluid are negative, although fluid examination is required only if septic arthritis is suspected.

TREATMENT

Bed rest, gentle skin traction, and the elimination of weight bearing are indicated. Equivocal cases may need hospitalization. The relief of pain and discomfort is usually rapid, and motion is restored in 2 to 4 days. Crutches are used for 2 to 4 weeks, and the patient is observed closely for up to 2 years, because Perthes’ disease may develop in some cases, but the exact relationship is uncertain. Antibiotics are used only when the disorder is associated with an infection elsewhere. Recurrences are possible.