4. Pediatrics MCQs

Prophylactic pinning of the contralateral hip in SCFE is controversial but is generally recommended in patients with a high risk of developing a contralateral slip. Strong indications include the presence of an endocrine disorder (such as hypothyroidism, panhypopituitarism, or renal osteodystrophy), prior radiation therapy, or presentation at a particularly young age (e.g., males <12 years, females <10 years). Age older than 14, female sex alone, chronicity, or severity of the current slip are not primary indications.

In a slipped capital femoral epiphysis (SCFE), the epiphysis actually remains held within the acetabulum by the ligamentum teres, while the femoral neck (metaphysis) displaces anteriorly and externally rotates relative to the epiphysis. On radiographs, this makes the epiphysis appear to have displaced posteriorly and inferiorly relative to the neck.

The gold standard for a mild, stable SCFE is in situ fixation using a single cannulated screw placed in the center of the epiphysis. Closed reduction is contraindicated due to the high risk of precipitating avascular necrosis. Open reduction (e.g., modified Dunn procedure) is typically reserved for severe or unstable slips to correct the deformity acutely while protecting the blood supply. Prophylactic pinning of the contralateral hip is performed in certain high-risk demographics, but the affected hip must be treated.

The Loder classification divides SCFE into stable (able to bear weight with or without crutches) and unstable (unable to bear weight). Unstable SCFE has a notoriously high rate of avascular necrosis (AVN) of the femoral head, historically reported up to 47%, compared to a near 0% AVN rate in stable slips. Prompt recognition and appropriate operative planning are required to mitigate this risk.

Prophylactic pinning of the contralateral hip in patients presenting with a unilateral SCFE is strongly recommended for those with underlying endocrine disorders (such as hypothyroidism, panhypopituitarism, and renal osteodystrophy) or a history of pelvic radiation. These patients have an exceptionally high rate of developing bilateral disease (often approaching 100%). Other relative indications include presentation at an age less than 10 years or the inability to reliably follow up.

The radiographs show a grade I slipped capital femoral epiphysis (SCFE) that is classified as stable because the child is able to bear weight. The elevated TSH level indicates possible hypothyroidism. SCFE usually occurs in boys age 12 to 14 years. Because of the patient's young age and hypothyroidism, he is at increased risk for slippage of the contralateral hip; therefore, prophylactic pinning of the uninvolved side also should be considered. Because of the risk of slip progression, crutch treatment and nonsteroidal anti-inflammatory drugs are not indicated. Realignment osteotomy is not indicated for grade I SCFE. Traction to reduce the slip, followed by pinning, has been advocated for unstable slips but is not indicated here. Loder RT, Wittenberg B, DeSilva G: Slipped capital femoral epiphysis associated with endocrine disorders. J Pediatr Orthop 1995;15:349-356.

Congenital dislocation of the knee is an uncommon deformity that varies in presentation from simple hyperextension to complete anterior dislocation of the tibia on the femur. Treatment varies with the age at presentation and the severity of the deformity. Most authors recommend early nonsurgical management. A recent study of 24 congenital knee dislocations in 17 patients found that satisfactory results were obtained in most instances using closed treatment. Based on their findings, the authors concluded that immediate reduction or serial casting should be performed when the patient is seen early after birth. If the patient is seen late and correction cannot be achieved by serial casting, traction followed by closed or open reduction may be necessary. Early percutaneous quadriceps recession has been described for complex congenital knee dislocations associated with underlying disorders, such as arthrogryposis and Ehlers-Danlos syndrome. Ko JY, Shih CH, Wenger DR: Congenital dislocation of the knee. J Pediatr Orthop 1999;19:252-259. Johnson E, Audell R, Oppenheim WL: Congenital dislocation of the knee. J Pediatr Orthop 1987;7:194-200.

In patients with myelomeningocele, the presence of bilateral hip dislocation does not affect ambulation, bracing requirements, sitting ability, degree of scoliosis, or level of comfort. There is little evidence to support active treatment of bilateral hip dislocations in patients with myelomeningocele proximal to L4. Fraser RK, Hoffman EB, Sparks LT, et al: The unstable hip and mid-lumbar myelomeningocele. J Bone Joint Surg Br 1992;74:143-146.

The deformity is too severe for observation, and at age 4 years, the child is too old for orthotic treatment. To prevent recurrence, surgery should be performed before irreversible changes occur in the medial physis. A proximal tibial osteotomy should overcorrect the mechanical axis to 10 degrees of valgus. Bar resection has not been shown to be as effective in this severe deformity, especially without a concomitant osteotomy. Raney EM, Topoleski TA, Yaghoubian R, Guidera KJ, Marshall JG: Orthotic treatment of infantile tibia vara. J Pediatr Orthop 1998;18:670-674.

Excessive internal tibial torsion is a common cause of intoeing in toddlers. In most children, this resolves spontaneously by 3 to 4 years of age. Intoeing in elementary age children is usually the result of excessive femoral anteversion. Studies have shown that active intervention (casting, splinting, and shoe modifications) has no demonstrable effect on the natural history or resolution of tibial torsion. Surgery is rarely indicated in adolescents with severe internal tibial torsion that has not resolved and is resulting in cosmetic and functional problems. Canale ST, Beaty JH: Operative Pediatric Orthopaedics. St Louis, MO, Mosby Year Book, 1991, pp 357-385.

The incidence of vascular injury in supracondylar humeral fractures is directly related to the degree and direction of displacement. Significant posterior lateral displacement tends to result in brachial artery and median nerve injuries, and posterior medial displacement may lead to radial nerve injury. The brachial artery is always injured at the level of the fracture; therefore, angiography or MRA will not assist in locating the injury. The treatment of choice is surgical reduction and stabilization of the fracture, followed by reassessment of the vascular status. If the hand is pink and warm or pulses can be detected with doppler, it is reasonable to follow the extremity closely after surgery. If the arm becomes pulseless and white, immediate anterior exploration of the arm is indicated. The artery is often entrapped in the fracture and once extricated, will provide adequate blood flow. If the artery is injured, a primary repair or vein graft is needed. Shaw BA: The role of angiography in assessing vascular injuries associated with supracondylar humerus fractures remains controversial. J Pediatr Orthop 1998;18:273. Sabharwal S, Tredwell SJ, Beauchamp RD, et al: Management of pulseless pink hand in pediatric supracondylar fractures of humerus. J Pediatr Orthop 1997;17:303-310.

The patient has a Salter-Harris type III fracture of the proximal phalanx of the thumb. It is usually caused by an abduction injury where the ulnar collateral ligament avulses a fragment away from the proximal epiphysis and is the most common childhood gamekeeper's injury. If there is greater than 1 mm of separation or a significant articular step-off, an open reduction, performed through an extensor aponeurosis-splitting approach, is required to reestablish joint congruity and stability. Percutaneous or closed methods of reduction are usually ineffective. The dorsal approach avoids the volar neurovascular structures. Since the ulnar collateral ligament is still attached, this area does not need to be visualized. The major goal is to reestablish joint congruity and bony stability. This can be easily performed via the dorsal approach.

The radiograph shows a recurvatum deformity of the proximal tibia with growth arrest of the tibial tubercle apophysis. This deformity has been described in association with femoral shaft fractures in children and has been attributed to a clinically silent, concommitant injury to the proximal tibial physes and also to iatrogenic injury associated with a proximal tibial traction pin. Overlengthened hamstrings and rupture of the posterior cruciate ligament may lead to knee hyperextension; however, these problems should not cause bone deformity. Osgood-Schlatter disease occurs when growth is nearly complete and usually leads to prominence of the tibial tubercle. Patellar tendon rupture is rare in children and would not cause this deformity unless the repair was performed with screws across the apophysis. Hresko MT, Kasser JR: Physeal arrest about the knee associated with non-physeal injuries of the lower extremity. J Bone Joint Surg Am 1989;71:698-703.

In the setting of a pediatric supracondylar humerus fracture with a 'pulseless, pink' hand, current guidelines support closed reduction and percutaneous pinning. If the hand remains pink and well-perfused (capillary refill < 2 seconds) post-reduction, the collateral circulation is sufficient. Observation is appropriate without immediate vascular exploration. Vascular exploration is indicated for a 'pulseless, white' (ischemic) hand that does not improve after reduction.

In a child with a displaced supracondylar humerus fracture and a 'pulseless, pink' hand, the limb is adequately perfused through collateral circulation. The most appropriate next step is urgent closed reduction and percutaneous pinning, as the pulse frequently returns following anatomic reduction. Vascular exploration is indicated if the hand becomes or remains poorly perfused (white and cool) after reduction.

The patient demonstrates an inability to flex the interphalangeal joint of the thumb (innervated by the flexor pollicis longus) and the distal interphalangeal joint of the index finger (innervated by the flexor digitorum profundus). This motor deficit, often tested by asking the patient to make an 'A-OK' sign, is indicative of an anterior interosseous nerve (AIN) palsy. The AIN is a branch of the median nerve and is the most commonly injured nerve in pediatric extension-type supracondylar humerus fractures.

A 'pulseless but pink' (well-perfused) hand following a displaced pediatric supracondylar humerus fracture indicates adequate collateral circulation. The initial treatment is urgent closed reduction and pinning to relieve pressure on the brachial artery.

In the Lenke classification, a minor curve is structural if it has a residual Cobb angle of 25 degrees or greater on supine lateral bending radiographs, or if there is kyphosis of at least +20 degrees.

TLSO bracing is indicated for skeletally immature patients (Risser 0-2) with progressive curves measuring between 25 and 40 degrees to halt curve progression.

Bracing is indicated for skeletally immature patients (Risser 0-2) with curves between 25 and 45 degrees. A dose-response relationship exists, with 16-23 hours per day providing the most effective curve progression prevention.