Pediatrics
Monica Kogan, MD, FAAOS, FAOA
Brian Scannell, MD, FAAOS
Mara S. Karamitopoulos, MD, FAAOS
Neither of the following authors nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter: Dr. Kogan, Dr. Scannell, and Dr. Karamitopoulos.
Introduction
Slipped capital femoral epiphysis (SCFE) is the most common hip disorder affecting adolescents between the ages of 9 and 16 years. The etiology is multifactorial and may vary with ethnicity, sex, and region. The practitioner should have a high index of suspicion for any patient who presents at ages 9 to 16 years with hip pain, knee pain, or a limp (either painless or painful). The diagnosis is made with plain radiographs or rarely MRI is performed when SCFE is suspected but the plain radiographs are inconclusive. Prompt identification is of utmost importance because SCFE may lead to devastating long-term consequences. Once identified, the treatment is surgical intervention. Developmental dysplasia of the hip includes acetabular dysplasia, hip subluxation dislocation. It previously was referred to as congenital dislocation of the hip; however, it was found to be a dynamic disorder. Routine screening is not indicated unless infants have known risk factors such as oligohydramnios, breech presentation, family history of developmental dysplasia of the hip, or an abnormal examination. Initial treatment is traditionally performed with a Pavlik harness, with excellent results. Infants in whom nonsurgical management failed are treated with surgical intervention and this may include a closed reduction and spica casting versus open hip reduction (medial or anteriorly) versus open hip reduction/femoral
osteotomy/acetabular osteotomy depending on the stability, severity, and patient’s age. These patients need to be followed for years to ensure that the dysplasia resolved and did not return. Clubfoot (talipes equinovarus) is a congenital disorder of the foot. The four aspects of the clubfoot include forefoot cavus, adductus, hindfoot varus, and equinus of the foot. Treatment with the Ponseti casting technique is the most common form of treatment with excellent results. Rarely do children require further intervention because of recurrence. Compliance with the Ponseti treatment protocol by the caregivers has been associated with improved, outcomes. Supracondylar humerus fractures in children are one of the most common elbow fractures in pediatric patients. Treatment depends on the severity of the injury. Nonsurgical management is reserved for nondisplaced fractures and surgical management reserved for fractures with displacement. An accurate physical examination is imperative, including the documentation of neurovascular status. Timing of surgical intervention is dependent on neurologic status (urgent) versus vascular status (emergent). Surgical treatment most commonly includes closed reduction and percutaneous pinning and rarely requires an open reduction and fixation. Intoeing is a common reason for pediatric orthopaedic evaluation. It refers to walking with the toes pointing inward (pigeon toed). For most children, the intoeing will resolve on its own by age 10 years. In a small number of children, intoeing will persist; however, it will not cause issues with function/activities/future problems. Reassurance is the most common recommendation for parents.
osteotomy/acetabular osteotomy depending on the stability, severity, and patient’s age. These patients need to be followed for years to ensure that the dysplasia resolved and did not return. Clubfoot (talipes equinovarus) is a congenital disorder of the foot. The four aspects of the clubfoot include forefoot cavus, adductus, hindfoot varus, and equinus of the foot. Treatment with the Ponseti casting technique is the most common form of treatment with excellent results. Rarely do children require further intervention because of recurrence. Compliance with the Ponseti treatment protocol by the caregivers has been associated with improved, outcomes. Supracondylar humerus fractures in children are one of the most common elbow fractures in pediatric patients. Treatment depends on the severity of the injury. Nonsurgical management is reserved for nondisplaced fractures and surgical management reserved for fractures with displacement. An accurate physical examination is imperative, including the documentation of neurovascular status. Timing of surgical intervention is dependent on neurologic status (urgent) versus vascular status (emergent). Surgical treatment most commonly includes closed reduction and percutaneous pinning and rarely requires an open reduction and fixation. Intoeing is a common reason for pediatric orthopaedic evaluation. It refers to walking with the toes pointing inward (pigeon toed). For most children, the intoeing will resolve on its own by age 10 years. In a small number of children, intoeing will persist; however, it will not cause issues with function/activities/future problems. Reassurance is the most common recommendation for parents.
SLIPPED CAPITAL FEMORAL EPIPHYSIS
Slipped capital femoral epiphysis (SCFE) is the most common hip disorder affecting adolescents between the ages of 9 and 16 years.1
It is defined as the displacement of the femoral head relative to the femoral neck and shaft in the physis.
The proximal femoral neck and shaft move anteriorly and rotate outwardly relative to the femoral head, leaving the femoral head within the acetabulum.2
Etiology is multifactorial:
Structural issues
Obesity
Hormonal causes
Seasonal and geographic variations1
Presenting symptoms may include a history of a limp, and hip or knee pain with or without a history of trauma.
Clinical examination findings may be subtle and a heightened sense of awareness is required in order for the diagnosis to be made in a timely manner; treatment delays can lead to worse outcomes.
Radiographs are obtained to confirm the diagnosis and if a SCFE is identified, prompt surgical stabilization is required.
Development of underlying health issues as patients age has been identified in patients treated for SCFE.
Educating adolescent patients on healthy lifestyle choices may help to prevent these issues from developing in the future.
Epidemiology
The incidence of SCFE is approximately 10 cases per 100,000 children.1
Incidence varies with ethnicity, sex, and region, ranging from 4.4 to 10.8 cases per 100,000 children.
Highest incidence of SCFE is in those with a Polynesian background (4.5 times higher than white children,) followed by black children (2 times higher).
Children of Indonesian-Malay and Indo-Mediterranean backgrounds have lower incidences of SCFE than white children (0.5 and 0.1, respectively).3
Hormonal or systemic diseases, such as hypothyroidism, growth hormone supplementation, and hypogonadal abnormalities have been associated with weakening of the physis and may result in SCFE.4
Boys are affected more often than girls, with a ratio 1.43:1.3
The average age for boys is 12.0 years and for girls is 11.2 years,5 attesting to the influence that hormones have on the physis.
A correlation has been identified between obesity and SCFE.
Cadaver studies have suggested that increased forces may lead to SCFE in obese children.6
Patients with severe obesity at age 11 to 12 years have been found to have a 17.0 times higher risk of SCFE than those who did not have obesity.7
Shearing forces exerted on the hips, especially in boys younger than 12 years and girls younger than 11 years, resulting in slippage of the epiphysis, especially when the perichondral ring is damaged.
Obesity is present in more than 50% of the children affected at any age.
Obesity was reported to be more prevalent in children with SCFE who were younger than 10 years and above the 97th percentile body mass index for age.8
Patients more commonly present with a unilateral SCFE.
Bilateral may occur in 20% to 40% of which those with bilateral involvement tend to occur at younger age.3 More than 80% of those presenting with a unilateral SCFE in whom a contralateral SCFE subsequently develops will do so within 18 months.9
Seasonal variations both north and south have been found to be associated with SCFE.
Geographic locations north of 40° latitude had 57.4% of SCFEs occur during the summer months.
57.3% of SCFEs presented during the winter months south of 40° latitude. This seasonal variation is thought to be linked to vitamin D production at different times of the year.5
Public Health Consideration
Long-term issues for patients with SCFE have been well documented and should be understood.
Regardless of the severity of slip, patients who have had a SCFE have been found to have a higher likelihood of underlying systemic disease and long-term health issues 20 years after presentation.10
Obesity has been found to continue into adulthood, with the patient’s mean body mass index over the study period increasing from 27 kg/m2 to 37 kg/m2.
When patients with SCFE were in their 30s, 8% to 16% of the patients were found to have diabetes, elevated blood glucose level, chest pain, and hypertension.10
These findings highlight the need for an increased surveillance of adult patients with a history of SCFE.11
It is important for the treating physician to begin stressing the importance of a healthy lifestyle to the patients and parents when they first present with SCFE to prevent medical comorbidities as the patients enter adulthood.
Other long-term issues have been seen in adult patients who sustained SCFE during their youth.
Pertinent Anatomy/Pathoanatomy
SCFE occurs through the proximal femoral physis, in the hypertrophic zone.
Weakening in the physis results in anterior displacement of the femoral neck in relation to the proximal femoral epiphysis, which remains in the acetabulum.2
It is important to remember that it is the metaphysis that displaces relative to the femoral head and that the femoral head remains in the acetabulum.
Anatomic associations have been identified in patients with SCFE:
Histologically, SCFE is characterized by physeal widening of the hypertrophic zone, enlargement of chondrocytes, cellular column disorganization, higher proteoglycan and extracellular matrix concentrations in the physis, and widespread disruption in chondrocyte differentiation and endochondral ossification.14
The retinacular vessels are the main blood supply to the epiphysis.
These vessels may be predisposed to disruption with displacement of the femoral metaphysis causing kinking or compression on the vessels.
The cause of osteonecrosis in unstable SCFE is unknown; however, multiple possible mechanisms have been proposed:15
Frank vascular laceration of the lateral ascending branch of the medial femoral circumflex artery
Vascular kinking
Spasm
Thrombosis due to infolding of the posterior soft-tissue envelope following epiphyseal displacement
Vascular tamponade due to increased intracapsular pressure beyond the perfusion pressure of the femoral head vascular supply
The epiphyseal tubercle has gained increasing attention over the years.
Located in the posterosuperior quadrant of the epiphysis
Believed to give mechanical strength to the physis and is believed to be crucial for physeal stability6
Epiphyseal tubercle decreases in size and surface area during childhood and adolescence14
Mechanical studies have revealed that childhood obesity may generate forces sufficient to overcome the yield point of the physis.
Peak age of SCFE is around puberty, and rapid growth of the bone is believed to lower the mechanical yield point for physeal injury.
Obesity around puberty, rather than earlier in childhood, is the most important time point in the development of the disease.7
Pertinent History/Physical Examination Findings
Presentation of SCFE may be obvious or subtle.
The clinician should always have a high index of suspicion for a SCFE in any patient who presents with a history of hip/thigh/knee pain, limp, or inability to bear weight,16 especially in a child age 10 to 15 years.
A delay in diagnosis may result in a worse outcome for the patient.
SCFE should always be high on differential diagnosis when a patient presents with the stated symptom.5
Other physical examination findings:
Outtoeing gait on the affected side
Obligate outward rotation of the hip when flexing the hip (Drehmann sign)
Limited inward rotation of hip when the hip is flexed 90°
Limited inward rotation of the hip is due to the anterolateral and superior displacement of the metaphysis relative to the epiphysis11
Unilateral SCFE is more common; however, involvement of both hips may occur in 40% of children. The patients who present with both hips involved tend to present at a younger age.
Bilateral SCFE can be present at the initial visit and more than 80% of those presenting with a unilateral SCFE in whom a contralateral SCFE subsequently develops will do so within 18 months.9
Parents should be advised to have a heightened awareness of any subtle symptoms in the opposite hip of the child.
Significant risk factors for contralateral SCFE:17
Patients younger than 10 years
Body mass index 95th percentile or higher
Presence of an endocrine abnormality
Higher posterior sloping angle of the unaffected hip
Lower modified Oxford score
Relevant Imaging
AP pelvis and frog-lateral radiographs of the hip should be obtained if there is a concern for SCFE.
Including the unaffected hip for comparison may also serve to identify if any findings of asymptomatic SCFE on the opposite side.
Radiographic findings suggestive of SCFE include:18
Subtle widening of the physis
Relative decreased height of the epiphysis
Loss of intersection of the epiphysis by a lateral cortical line along the femoral neck (Klein line) (Figure 1)
Double density detected at the metaphysis (Steel sign, which is caused by posterior slip of the epiphysis)
Southwick classification is a radiographic method that can be used to assess the magnitude of the slip.19
Angle measured on an AP or the frog-lateral view of the bilateral hips
Line drawn perpendicular to a line connecting two points at the posterior and anterior tips of the epiphysis at the physis, on the lateral radiograph, or inferior and superior edge of the epiphysis on the AP radiograph
Third line is drawn down the axis of femur
Figure 1 A and B, Radiographs showing Klein line. On the right side normal alignment is revealed; on the left side the line does not intersect the femoral head.
Angle between the perpendicular line and the femoral shaft line is Southwick angle; measured bilaterally
Slipped side then subtracted from the normal side, which is measured in the same manner
In the case of bilateral involvement, 12° is the normal reference value for the lateral view and 145° on the AP view as a reference for the unaffected hip.
The number calculated determines the severity.
Mild, less than 30°
Moderate, 30° to 50°
Severe slip, greater than 50°
Others use a grading system based on percentage of slippage of the epiphysis on the metaphysis, with mild zero to 33%, moderate 34% to 50%, and severe slips being >50% slippage.
The peritubercle lucency sign on radiographs is considered to be accurate and reliable for the early diagnosis of SCFE.20
On AP radiographs, the epiphyseal tubercle is usually found in the central one-third of the epiphyseal plate.
On lateral radiographs, the tubercle is usually located at the posterior third quadrant of the epiphyseal plate.
The peritubercle luceny sign includes focal changes around the tubercle including widening or enlargement of the corresponding metaphyseal fossa, with or without adjacent osteolysis or sclerosis.20
Most recently, it was reported that the peritubercle lucency sign on radiographs is accurate and reliable for the early diagnosis of SCFE compared with MRI as the gold standard.20
If there is a clinical suspicion of a SCFE and radiographs are negative, MRI can be performed and has been considered the gold standard.
MRI findings consistent with a SCFE can include:
Physeal widening
Greater signal intensity of the proximal femoral physis compared with the physis of the greater trochanter
SCFE can be classified in three ways:
Radiographically
By the length of symptoms
Figure 2 MRI was performed because of vague symptoms on the right side with radiographic findings of slipped capital femoral epiphysis on the left. Edema in the physis on the left along with physeal widening seen compared with the normal right side.
By the ability or inability to bear weight even with the use of crutches (Loder classification)
Depending on the length of symptoms, SCFE can be classified as acute, acute-on-chronic, and chronic.
An acute SCFE is characterized by the presence of symptoms for less than 3 weeks.
Pain that occurs suddenly
A chronic SCFE has symptoms for more than 3 weeks.
Represents most patients who present with SCFE
Acute-on-chronic SCFE is diagnosed when symptoms are present for more than 3 weeks but with an abrupt exacerbation of pain and/or inability to walk.
Loder classification is often used and is based on the ability/inability to walk either with or without crutches (stable versus unstable). This classification system is important because those with unstable SCFEs have been found to have worse outcomes than those with stable SCFEs.
Patients who are unable to walk either with or without crutches are classified as having an unstable SCFE.
Patients who are able to walk with or without crutches are classified as having a stable SCFE.
Nonsurgical Measures
For historical purposes only, SCFEs had been managed by removal of load and traction of the limb followed by immobilization in a plaster cast or observation22 because it was thought that this would be enough to halt the progression of the SCFE.
Nonsurgical management of SCFE, however, was found to lead to increased rates of chondrolysis, which was as high as 28% in patients with moderate slips.
17% of SCFE cases progressed with additional slippage when they were treated nonsurgically.
Continued presence of an open epiphyseal plate constituted a risk of progression to slippage after diagnosis.
Currently, nonsurgical management is not the standard of care and these patients are treated with surgical stabilization.
Surgical Intervention
Surgical intervention is indicated for any SCFE identified in a patient, regardless of the length of symptoms, severity of slip, ability/inability to bear weight, or radiographic findings. The goal of treatment is to prevent further slippage, achieve stable closure of the proximal femoral physis, improve the alignment of the epiphysis on the femoral neck, and to prevent chondrolysis and osteonecrosis.1
Surgical intervention is the standard of care when a patient presents with a SCFE.
There are different approaches depending on the stability of the slip as well as the surgeon’s comfort level and experience with the procedures.
The most common treatment for SCFE (stable and unstable) remains percutaneous in situ fixation using single-screw or double-screw fixation.
The goal of all treatment is to prevent further slippage.
Traditionally, fixation is performed without attempting a formal reduction of the slip, which can leave the epiphysis in a displaced position.
Positional or an incidental reduction may occur while the patient is positioned; however, a formal reduction maneuver is never performed.
Both single-screw and double-screw fixation has been described.
Excellent results have been reported when using a single screw in cases of mild and moderate slippage, with success rates of 91% to 95%.11,13
Double-screw fixation is another option in the management of both stable and unstable SCFEs; however, it has not shown any biomechanical or clinical advantage to placement of a single screw.23
For this reason, as well as technical challenges of placing double screws, single-screw placement is more commonly performed.
An increase in the intracapsular pressure in hips with unstable SCFE has been found to be twice that of the nonaffected hip.
Drastic pressure increases have been seen with manipulation and then normalization after capsulotomy.24
A capsulotomy can be performed either through aspiration or through open capsulotomy to decompress the joint before in situ pinning.
In situ pinning is the more common surgery performed; it does not always reach the goal of prevention of hip arthritis because it does not improve the alignment of the epiphysis.25
Osteonecrosis rates vary between 10% and 40% with this technique26 depending on the stability of the SCFE.
The surgical hip dislocation or modified Dunn procedure allows for an anatomic reorientation of the epiphysis.
Acute, unstable, and chronic, as well as stable, SCFE can be successfully managed with the modified Dunn procedure.
Complication rate is statistically higher in patients with stable SCFE, specifically both osteonecrosis rate and postoperative instability.
The modified Dunn procedure allows for an anatomic reorientation of the epiphysis.
It is a procedure with a steep learning curve.
It should be performed only in a referral center as a statistically significant association between surgeon experience and osteonecrosis has been identified.27
The technique permits the surgeon to manage associated lesions, such as early acetabular labrum and cartilage damage or the metaphyseal bump that limits internal rotation, leading to femoroacetabular impingement, which can occur even in mild slips.
Early reports were encouraging, with restoration of alignment of the proximal femoral epiphysis and low rates of complications such as osteonecrosis.
Recent publications have documented higher complication rates resulting in decreased enthusiasm for this procedure.28
Technique: In Situ Pinning
SCFE is pinned in situ, which means pinning without a formal reduction.
A positional or serendipitous reduction can occur when an unstable slip reduces to some degree by placing the patient on the fracture table with the patella facing anteriorly and the surgical limb in neutral or slight abduction.
Positional reduction and pinning remain the gold standard, especially in mild to moderate stable and unstable slips because it yields reliable functional and radiographic outcomes at long-term follow-up (Figure 3).
Preferred entry point for the screw should be lateral to the intertrochanteric line on the AP view to ensure the screw heads will be extracapsular to avoid impingement.
Ideally the screw(s) are placed perpendicular to the physis.
For the severe slips, to keep the screw within the femoral head a more oblique trajectory may be necessary.
The goal is for 40% to 60% of the threads to cross the physis into the epiphysis as this provides the greatest load to failure.
Figure 3 A, Radiograph showing left unstable slipped capital femoral epiphysis presenting with acute pain and inability to bear weight. B, Intraoperative fluoroscopic view after incidental reduction. C and D, Postoperative AP and lateral views are shown.
This can be done with a fully threaded or 32-mm partially threaded cannulated screw.
Once the screw is secured, the approach withdrawal technique is then used to ensure a safe screw tip-subchondral bone distance, 2.5 to 5 mm from the subchondral bone.
The hip is brought from maximum internal rotation to maximum external rotation.
As the limb is moved through this arc of motion, the screw appears to move closer to the subchondral bone (approach) and then appears to move further from it (withdrawal).
The point at which the screw appears to transition from approach to withdrawal represents the closest position to the joint and can reveal unrecognized screw penetration.29
Postoperative Orders
Postoperatively the patient’s weight-bearing status depends on the procedure performed and the stability of the slip.
In stable SCFE managed with in situ pinning, the patient should practice partial weight bearing for 4 to 6 weeks and then progress to full weight bearing. Sports and running can resume at 3 to 6 months.
In instable SCFE, the patient does not bear weight for 4 to 6 weeks, followed by progressive weight bearing with crutches.
Pain should be well controlled postoperatively and most patients require acetaminophen and ibuprofen. Stronger narcotics are usually not required.
Pearls and Pitfalls
The incidence of osteonecrosis is most strongly associated with the stability of the slip at presentation.30
A prompt diagnosis is an important measure to prevent these sequelae.
It is imperative to have a heightened suspicion for a SCFE in children age 10 to 15 years with a limp, hip pain, or knee pain as increased duration of symptoms before diagnosis is associated with greater slip angles.
Slip angle may be associated with an impaired Harris hip score and higher radiographic grades of osteoarthritis later in life.31
Placing the screw in the center of the epiphysis is important.
Screws placed in the posterior superior quadrant of the femoral neck are associated with a high incidence of osteonecrosis as it can affect the perfusion coming from the lateral epiphyseal vessels.
The screw should not penetrate the joint because persistent pin penetration into the hip joint has been associated with chondrolysis.32
Care should also be taken to ensure that the entry point is not below the level of the lesser trochanter as this can predispose the patient to a fracture.
The screw ideally should be placed lateral to the intertrochanteric line to avoid impingement of the screw head with the acetabulum.
Outcomes
In situ fixation is the most common treatment performed for stable/unstable hips with mild to moderate slips.
Greater slips can be managed with in situ pinning; however, the risk of impingement from the residual deformity may be higher and may warrant an anatomic realignment to restore hip anatomy (Figure 4).
A formal closed manipulation to achieve anatomic realignment is no longer performed because it does not allow direct control of the retinacular vessels and can result in a higher incidence of osteonecrosis.
The modified Dunn procedure is safe, efficient, and reproducible, but should be performed by surgeons experienced with the procedure.
Timing of surgery is thought to be crucial to the development of osteonecrosis. It is also thought that surgery should be performed within 24 hours from the onset of symptoms.33
Bilateral involvement in SCFE ranges from 14% to 63%.
Risk can increase to up to 80% when diagnosed at a very young age and up to 100% when endocrinopathies are associated.
Prophylactic surgical treatment remains controversial as reports of osteonecrosis in the contralateral asymptomatic hip have been reported, resulting in devastating outcomes (Figure 5, A and B).
Prophylactic treatment of an asymptomatic hip without radiographic findings should be reserved for a selected cohort of
patients, such as very young children, presence of endocrinopathy, patients with obesity, and those whose follow-up is thought to be difficult.
Figure 4 A, Radiograph of stable slipped capital femoral epiphysis pinned in situ with residual deformity. B, Radiograph showing prominence of lateral metaphysis.
Osteonecrosis in unstable SCFE was found to be as high as 21%.
More recent studies show promising results with a lower osteonecrosis rate after urgent reduction, decompression and fixation, or open reduction and fixation.
Presence of an increased intracapsular hip pressure and the effect of joint decompression have been studied in unstable hips with SCFE with divergent conclusions.24
The role of increased intracapsular pressure in the development of osteonecrosis in unstable SCFE remains unclear, although a recent prospective series with precapsulotomy and postcapsulotomy vascular flow measurements suggests that capsulotomy with confirmed return of blood flow to the femoral head entirely removes the risk of osteonecrosis.34
In patients with unstable SCFE, the increase in intracapsular pressure can simulate a compartment syndrome-like phenomenon in the joint capsule, with postcapsulotomy pressures lower than predecompression reading.24
Other studies have not been able to confirm that capsular decompression lowered the rate of osteonecrosis following unstable SCFE, but recommended the surgeon weigh the minor
risks of this added procedure against the lack of conclusive evidence showing a lower osteonecrosis rate.35
Figure 5 AP and lateral radiographs from a 9-year-old boy who presented with an unstable left slipped capital femoral epiphysis. A, Modified Dunn procedure on the left hip and because of the patient’s young age a prophylactic pinning was performed on the right hip. B, Lateral radiographs of bilateral hips 2 weeks postoperatively. C, Six months postoperatively the patient presented with pain in the right hip with osteonecrosis present and screw penetration into the hip joint.
Mild SCFE deformity has been shown to contribute to abnormal joint kinematics and the development of degenerative arthritis of the hip.36
In one recent study at 20-year follow-up, 5% of patients with SCFE were found to have undergone total hip arthroplasty, revealing an increased risk of degenerative joint disease compared with the average population.37
Top 10 Knowledge Drops for Your Rotation
It is important to remember that it is the metaphysis that displaces relative to the femoral head and that the femoral head remains in the acetabulum.
Osteonecrosis is more common with unstable SCFE.
The most common treatment for stable and unstable SCFE is in situ pinning. Surgical hip dislocation/modified Dunn procedure should be performed in patients with unstable SCFE by surgeons with experience in the procedure.
The surgical hip dislocation/modified Dunn procedure has a higher risk of osteonecrosis and postoperative hip instability when performed on stable SCFE.
For in situ pinning of a SCFE, one screw is just as effective as two screws.
For in situ pinning, full threaded or 32-mm threaded screws are preferred and shoudl cross the physis.
SCFE can present with knee pain and it is important to have a heightened sense of awareness when examining the hip in any patient age 10 to 15 years who presents with a limp/knee pain/hip pain.
For in situ pinning procedures, a formal reduction is not recommended; however, an incidental reduction is often seen while positioning the patient on the table.
More than 80% of those presenting with a unilateral SCFE in whom a contralateral SCFE subsequently develops will do so within 18 months; patients should be counseled that any sort of discomfort in the contralateral hip should be worked up.
At patient presentation, an AP and frog-lateral pelvis radiograph should be obtained of both hips to ensure that there is not a SCFE on the contralateral side, because 20% to 40% of children will present with bilateral involvement.
DEVELOPMENTAL DYSPLASIA OF THE HIP
Developmental dysplasia of the hip (DDH) spans a wide range of disorders including acetabular dysplasia, hip subluxation, and dislocation of the hip.
Previously DDH was referred to as congenital dislocation of the hip; it is now understood that it is a dynamic disorder and a developmental issue versus a congenital one.
Early diagnosis is important to help improve results and decrease future issues.
Nonsurgical management with a Pavlik harness is the most common treatment with very good outcomes.
Surgical intervention is reserved for hips in which nonsurgical management fails.
Long-term issues can be seen and include persistent dysplasia, osteonecrosis, and early osteoarthritis.
Epidemiology
Incidence of DDH is variable and is multifactorial.
Approximately 1 in 1,000 children is born with a dislocated hip, and 10 in 1,000 may have hip subluxation.38
Prenatal and postnatal factors are found to be associated with DDH.
Prenatal factors include breech presentation, female sex, positive family history, firstborn status, and oligohydramnios.
The most important risk factors are intrauterine position, sex, race, and positive family history.
The left hip is more commonly involved (60% of children) because of the common intrauterine positioning of left occiput anterior, which results in the left hip adducted against the mother’s sacrum.
The right hip is affected in 20% of children, and 20% of children have both hips affected.39
Females are affected more than males because of the increased ligamentous laxity secondary to the circulating maternal hormones and the additional effect of estrogens that are produced by the female infant’s uterus.
A family history positive for DDH may be found in 12% to 33% of affected patients.
Risk for DDH to develop in a child is 6% if one of their siblings has DDH, 12% if one of their parents has DDH, and 36% if both a parent and a sibling have DDH.40
DDH is common in children who present in the breech position.39
In utero knee extension of the infant in the breech position results in sustained hamstring forces around the hip and contributes to subsequent hip instability.
Firstborn children are affected twice as often as subsequent siblings, presumably because of an unstretched uterus and tight abdominal structures in the mother.
Postnatal positioning also can play a role in DDH.
In cultures in which swaddling with the legs extended is practiced (Native American and Asian), there is a higher incidence of DDH.
In these positions the legs are extended, which forces the hips into adduction and extension resulting in abnormal forces within the joint.
Cultures where the infants/children are carried astride the hips (African/Eskimo) have a very low incidence of DDH.41
One in 60 newborns has hip instability, and more than 60% of them stabilize in the first week without any treatment, and a total of 88% stabilize within the first 2 months. The remaining 12% have DDH that will persist.42
Timely and successful reduction of the hip(s) yields acceptable outcomes into adulthood.
A delay in treatment can result in persistence of hip dysplasia into adolescence and adulthood, which may result in abnormal gait, decreased strength, limb-length discrepancy with a flexion/adduction deformity of the hip, increased rate of degenerative hip joint disease, postural scoliosis, back pain, and ipsilateral genu valgum with consequent arthritis of the knee.43
Pertinent Anatomy/Pathoanatomy
Bony and soft-tissue anatomy may block the reduction of the hip.
Blocks to a concentric reduction include inverted labrum, presence of a limbus, hypertrophied ligamentum teres, pulvinar, contracted capsule, contracted transverse acetabular ligament (TAL), and contracted iliopsoas.
The femoral head stimulates the acetabulum to develop and vice versa.
The longer the femoral head is not anatomically positioned, the more severe is the dysplasia.
Anatomic findings on the femoral side include femoral anteversion and a smaller femoral ossific nucleus (Figure 6).
Soft-tissue adaptations develop at the labrum, limbus, ligamentum teres, pulvinar, TAL, iliopsoas tendon, and hip-joint capsule.
The acetabular labrum, a fibrocartilaginous structure located at the acetabular rim, enhances the depth of the acetabulum by 20% to 50% and contributes to the growth of the acetabular rim.
As the femoral head migrates proximally, the labrum gradually everts and hypertrophies because of the abnormal pressure.
The limbus (fibrous tissue) develops secondary to mechanical stimulation of the dislocated hip and merges with the hyaline cartilage of the acetabulum at its rim.
The limbus may then prevent concentric reduction of the hip.
With dislocation of the hip(s), the ligamentum teres lengthens, hypertrophies, and may block concentric reduction of the femoral head in the acetabulum.
Pulvinar, a fibrofatty tissue, within the acetabulum, may prevent acceptable reduction of the femoral head within the acetabulum.
The ligamentum teres inserts on the TAL, located at the base of the acetabulum.
Figure 6 A, Radiograph shows small femoral head with a dysplastic acetabulum. B, Radiograph shows bilateral dislocation and lack of development of the femoral head.
Figure 7 Arthrogram shows hourglass constriction caused by the iliopsoas tendon overlying the hip capsule (arrow).
As the hip displaces, the femoral head migrates proximally, the ligamentum teres pulls on the TAL, causing it to contract, and results in a narrowing of the acetabulum. Incising the TAL is essential for complete reduction of the hip because it is a major block to concentric reduction.
As the hip displaces, the iliopsoas contracts and can prevent the reduction of the hip.
The hourglass constriction often seen on an arthrogram is caused by the tight iliopsoas overlying and compressing the cap sule (Figure 7).
Understanding the anatomy in a patient with DDH is crucial to ensure that the obstacles to a concentric reduction have been addressed, allowing the femoral head to seat well within the acetabulum.
Pertinent History/Physical Examination Findings
DDH is a dynamic process and encompasses a range of findings.
It is important to understand the terminology used when describing these patients.
A dislocated hip is one where there is no articular contact between the femoral head and the acetabulum, which may be irreducible or reducible.
A subluxated hip is present when the femoral head is partially displaced from its normal position, but some degree of contact with the acetabulum still remains.
The hip is called dislocatable when application of a posteriorly directed force on the hip positioned in adduction leads to complete displacement of the femoral head from the margins of the acetabulum. Similarly, the hip is called subluxatable, if the femoral head is able to glide but not completely lose contact with the acetabulum.
Acetabular dysplasia describes the abnormality in the development of the acetabulum, including an alteration in size, shape, and organization.44
The physical examination begins with a complete assessment of the child from head to toes.
DDH may be considered a packaging disorder, and associated conditions such as torticollis, metatarsus adductus, and clubfoot should be ruled out.
Hip examination begins with the inspection for asymmetrical gluteal or thigh skin folds.
Unequal skin folds do not confirm a dislocated hip; patients with a dislocated hip will often have asymmetrical skin folds but not all children with asymmetric thigh folds will have a dislocated hip (Figure 8).
Assessment of a limb-length inequality is performed by placing the child in a supine position with the hips and knees flexed. Unequal knee heights might be noticed (Galeazzi sign), revealing
an apparent limb-length inequality with a subluxated or dislocated hip (Figure 9).
Figure 8 A, Photograph shows asymmetrical femoral skin folds. B, Radiograph showing normal presentation of the hips of a patient with asymmetrical skin folds.
Figure 9 Photograph shows Galeazzi sign revealing an apparent limb-length inequality in the patient’s left leg, which has a dislocated hip.
Understanding the normal range of hip abduction is important; as with bilateral hip dislocations the hip examination may not show asymmetry but abnormality may still be present.
Hip range of motion should be assessed for any asymmetry or restricted hip abduction.
In an infant, maximal abduction of the hips should be greater than 60°; if it is less, a dislocated hip should be suspected.
The next steps in the physical examination are provocative dynamic tests that assess stability, such as the Ortolani and Barlow maneuvers.45
Each hip must be examined separately.
The Ortolani maneuver reduces a dislocated hip into the acetabulum.
The child should be supine with the hips flexed to 90°. The examiner should place their index and long fingers laterally over the child’s greater trochanter with the thumb medially along the inner thigh near the groin crease.
The pelvis is stabilized by holding the contralateral hip still while performing the examination.
The examiner gently abducts the hip being tested while simultaneously exerting an upward force through the greater trochanter laterally.
The sensation of a palpable clunk is a positive Ortolani test and represents the reduction of a dislocated hip into the bony acetabulum.
The Barlow test subluxates or dislocates the hip posteriorly from a reduced position.
To perform the Barlow test, the pelvis is held stable and the patient is positioned in a manner similar to the Ortolani test.
The examiner adducts the hip and exerts a gentle downward force (toward the examining table) in an attempt to subluxate or dislocate an unstable hip posteriorly.
These tests generally are only useful in infants 3 months or younger because after this time period soft-tissue contractures may limit the motion of the hip.
In children older than 3 months, asymmetry or limitation of abduction becomes the most reliable sign associated with DDH and if noted a further workup is warranted.
It should be noted that in an ambulating child, a limp may also be seen on the physical examination as the limb is apparently short.
Children with bilateral hip dislocations may be difficult to identify and the clinician should have a heightened sense of awareness of the clinical findings in this scenario.
These children may have a Trendelenburg sign, waddling gait, hyperlumbar lordosis, and symmetrical but decreased hip abduction46 (Figure 10).
DDH is not a cause for walking delay in children; a recent controlled study suggested that even though the median time to the age of independent walking was 1 month less in healthy control patients compared with that of children with late presentation of DDH, it was clinically insignificant because they all walked within the expected time.47
DDH is an evolving process; a normal physical examination finding as an infant does not preclude a subsequent diagnosis of DDH.46 Any changes in a physical examination (eg, range of motion of hip/gait abnormalities/limp) should warrant a further workup.Related posts:
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