This practice set contains high-yield board review questions covering key concepts in 4. Pediatrics. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
Question 1761
Topic: Pediatric Hip
A 9-year-old boy presents with an acute-on-chronic slipped capital femoral epiphysis (SCFE) of the left hip. Prophylactic pinning of the asymptomatic, radiographically normal contralateral right hip is strongly indicated if the patient has a history of which of the following?
Correct Answer & Explanation
. Recent growth hormone therapy or hypothyroidism
Explanation
The overall risk of a contralateral slip in patients with SCFE is approximately 20-25%. However, prophylactic pinning of the contralateral asymptomatic hip is strongly recommended in patients with specific high-risk profiles, including underlying endocrine disorders (such as hypothyroidism, panhypopituitarism, or growth hormone therapy), previous pelvic radiation therapy, or presentation at an unusually young age (typically under 10 years for boys).
Question 1762
Topic: Pediatric Hip
A 6-week-old female with developmental dysplasia of the hip (DDH) is being treated with a Pavlik harness. Her hips were noted to be dislocated and irreducible (Ortolani negative) at presentation. Ultrasound at 3 weeks shows persistent dislocation. What is the most appropriate next step in management?
Correct Answer & Explanation
. Discontinue the Pavlik harness and switch to rigid abduction bracing or plan for closed reduction
Explanation
Continued use of a Pavlik harness in an persistently dislocated (irreducible) hip beyond 3 to 4 weeks is strictly contraindicated. Prolonged use in this setting compresses the femoral head against the posterior acetabular rim, causing 'Pavlik harness disease' (erosion of the posterior acetabulum) and a significantly increased risk of avascular necrosis. The harness must be abandoned in favor of rigid bracing or transition to closed reduction and spica casting.
Question 1763
Topic: Pediatric Hip
A 12-year-old obese male presents with a stable slipped capital femoral epiphysis (SCFE) of the left hip. During surgical planning, prophylactic pinning of the asymptomatic right hip is discussed. Which of the following is the strongest specific indication for prophylactic pinning of the contralateral hip?
Correct Answer & Explanation
. Presence of an underlying endocrine disorder such as hypothyroidism or renal osteodystrophy
Explanation
While there is ongoing debate regarding universal prophylactic pinning of the contralateral hip in SCFE, strong, generally accepted indications include the presence of an underlying endocrine or metabolic disorder (e.g., hypothyroidism, growth hormone deficiency, renal osteodystrophy) or previous radiation therapy. These conditions carry a much higher risk (often >50%) of bilateral involvement compared to idiopathic cases.
Question 1764
Topic: Pediatric Hip
A 13-year-old obese boy presents to the emergency department with severe left hip pain and inability to bear weight for the past 24 hours. Radiographs confirm a slipped capital femoral epiphysis (SCFE). He cannot ambulate even with crutches. Which of the following management strategies minimizes the risk of avascular necrosis in this patient?
Correct Answer & Explanation
. Urgent open reduction and internal fixation with capsulotomy
Explanation
This is an unstable SCFE, defined by the inability to bear weight, which carries a high risk of avascular necrosis (AVN). Urgent incidental reduction, fixation, and capsulotomy/decompression is advocated to relieve intracapsular tamponade and reduce AVN risk.
Question 1765
Topic: Pediatric Hip
A 13-year-old boy presents with severe left hip pain and inability to bear weight after a minor fall 2 days ago. Radiographs demonstrate a displaced slipped capital femoral epiphysis (SCFE). Which of the following is the most significant prognostic factor for the development of avascular necrosis (AVN)?
Correct Answer & Explanation
. Instability of the slip
Explanation
An unstable slip, defined by the inability to bear weight even with crutches, is the most significant risk factor for developing AVN. Rates of AVN in unstable SCFE can be as high as 47%, compared to nearly 0% in stable SCFE.
Question 1766
Topic: Pediatric Hip
A 4-week-old female infant is diagnosed with a completely dislocated left hip that is reducible on examination (Ortolani positive). A Pavlik harness is applied. At the 3-week follow-up ultrasound, the hip remains persistently dislocated. What is the most appropriate next step in management?
Correct Answer & Explanation
. Discontinue the harness and plan for closed reduction with spica casting
Explanation
Failure of a Pavlik harness to achieve reduction of a dislocated hip within 3 to 4 weeks is an absolute indication to discontinue the harness to prevent Pavlik harness disease (posterior acetabular wear). The next appropriate step is typically a closed reduction and spica casting under anesthesia.
Question 1767
Topic: 4. Pediatrics
What is the most likely diagnosis for her condition?
Correct Answer & Explanation
. Congenital amniotic band syndrome
Explanation
DISCUSSION: Streeter dysplasia or amniotic band syndrome is a congenital disorder caused by entrapment of fetal parts (usually a limb or digits) in fibrous amniotic bands in utero. It is associated with cleft lip or palate, terminal amputations, constriction bands, encephalocele, renal abnormalities, cardiac defects, hemihypertrophy, anterolateral bowing, tibial pseudarthrosis, and limb-length discrepancy. Clubfoot is seen in up to 25% of cases. Tight bands around the peroneal nerve that occur in 50% of children with clubfeet can lead to nerve damage. This patient has chronic osteomyelitis resulting from pressure on the fifth metacarpal head in the presence of an insensate lateral foot. Traditional pinning in open clubfoot surgery does not breach the distal metatarsal. In an open procedure, releasing the abductor hallucis addresses forefoot abduction and is performed medially. The lateral release impacts the midfoot and hindfoot, but not lateral ray plantar flexion.
Question 1768
Topic: 4. Pediatrics
A senior resident is scheduled to perform a posterior medial release on a 10-month-old infant who has a congenital clubfoot deformity. Informed consent is obtained for the procedure. The supervising surgeon is obligated to give the parents what information?
Correct Answer & Explanation
. The resident will be performing the procedure and the supervising surgeon will actively participate.
Explanation
DISCUSSION: Informed consent is generally considered to be a process of mutual decision making between the physician and patient. The physician is required to provide to the patient all material information that is needed for the patient to make an informed decision. The courts have held that a patient’s choice of surgeon is as important to the consent as the procedure itself. Assistance by a surgical trainee with adequate supervision is permissible when there has been adequate disclosure. Adequate supervision may be defined as active participation by the attending during the essential parts of the procedure. Allowing a substitute surgeon to operate on a patient without the patient’s knowledge (ghost surgery) may result in charges of battery against the substitute surgeon and malpractice against the surgeon to whom the patient gave consent. REFERENCES: Kocher MS: Ghost surgery: The ethical and legal implications of who does the operation. J Bone Joint Surg Am 2002;84:148-150. Holmes MK: Ghost surgery. Bull NY Acad Med 1980;56:412-419.
Question 1769
Topic: 4. Pediatrics
A 3-year-old boy with severe cerebral palsy is unable to sit independently and does not crawl. Examination reveals a 40-degree hip flexion contracture by the Thomas test and 25 degrees of passive abduction. A radiograph of the pelvis shows subluxation of both hips, with a migration index of 30%. Management should consist of
Correct Answer & Explanation
. bilateral release of the adductor and iliopsoas muscles.
Explanation
DISCUSSION: Progressive hip subluxation occurs in up to 50% of children with spastic quadriparesis. The subluxation is the result of chronic muscle hypertonicity, especially in the adductor muscle group. In time, the constant muscle tension will lead to dislocation, dysplastic changes in the acetabulum, and erosive changes in the cartilage of the femoral head. Many of these children will experience pain. Two recent studies have shown that early soft-tissue releases can successfully prevent progressive subluxation in children who are younger than age 4 years and who have a Reimers index (migration index) of less than 40%. Botulinum toxin A injections may reduce tone in the adductors for 4 to 6 months, but it is difficult to inject into the iliopsoas. Additionally, there are no long-term studies documenting the efficacy of botulinum toxin A to treat progressive hip subluxation in patients who have spastic quadriparesis. In general, proximal femoral osteotomy, combined with soft-tissue release as necessary, is indicated in older children (older than age 4 years) with progressive subluxation. Although selective dorsal rhizotomy has been used in nonambulatory patients, outcomes are less well documented than in ambulatory patients. There are no studies documenting the effect of selective dorsal rhizotomy on progressive hip subluxation in nonambulatory children. REFERENCES: Miller F, Cardoso Dias R, Dabney KW, et al: Soft-tissue release for spastic hip subluxation in cerebral palsy. J Pediatr Orthop 1997;17:571-584. Cornell MS, Hatrick NC, Boyd R, et al: The hip in children with cerebral palsy: Predicting the outcome of soft tissue surgery. Clin Orthop 1997;340:165-171.
Question 1770
Topic: Pediatric Hip
A 48-year-old woman reports bilateral thigh pain that is limiting her function as a librarian. A radiograph and a bone scan are shown in Figures 23a and 23b. What is the most likely diagnosis?
Correct Answer & Explanation
. Rheumatoid arthritis
Explanation
The radiograph reveals bilateral severe acetabular protrusio. The bone scan and history confirm involvement of multiple joints, including the knees and the hindfoot. Although the first four choices can all cause the acetabular protrusio, the associated multiple joint involvement suggests the diagnosis of rheumatoid arthritis. Arthrokatadysis, or primary protrusio acetabuli, is often associated with osteomalacia but not other joint disease. Developmental dysplasia is a common cause of bilateral hip pathology but does not have acetabular protrusio. Resnick D: Diagnosis of Bone and Joint Disorders, ed 3. Philadelphia, PA, WB Saunders, 1995, pp 956-957. Wheeless' Textbook of Orthopaedics: Acetabular Protrusio. www.wheelessonline.com/ortho/acetabular_protrusio
Question 1771
Topic: Pediatric Lower Extremity
Figure 29 shows the AP radiograph of a 14-year-old boy. The radiographic findings are most consistent with what pathologic process?
Correct Answer & Explanation
. Infantile Blount's disease
Explanation
The severe depression of the proximal medial tibial epiphysis is most consistent with the diagnosis of neglected infantile Blount's disease. Blount's disease in adolescents produces a deformity in the metaphyseal region. Septic arthritis and JRA affect both sides of the joint. Hemophilia produces a characteristic widening of the intercondylar notch. Thompson GH, Carter JR: Late-onset tibia vara (Blount's Disease). Clin Orthop 1990;255:24-35.
Question 1772
Topic: Pediatric Hip
A 9-year-old girl reports the immediate onset of severe groin pain and the inability to walk after tripping on a curb. Examination reveals marked hip pain with passive range of motion. A radiograph is shown in Figure 21. Regardless of treatment, what is the most common complication following this injury?
Correct Answer & Explanation
. Osteonecrosis of the femoral head
Explanation
The patient has an unstable slipped capital femoral epiphysis (SCFE). According to the classification system based on physeal stability, an unstable SCFE is one in which the patient is unable to walk, even with crutches. Ishemic necrosis, or osteonecrosis, of the femoral head is the most devastating complication of SCFE. One study found a 47% incidence of ischemic necrosis following unstable slips. This complication is most likely the result of vascular injury associated with initial femoral head displacement rather than the result of either tamponade from joint effusion or gentle repositioning prior to stabilization. Chondrolysis is a relatively uncommon complication following treatment of SCFE. This complication has been associated with persistent penetration of the hip joint with screws or pins used to stabilize the femoral head or with spica cast immobilization. There are no reports to suggest that osteochondritis dissecans, nonunion, or coxa magna follows treatment of SCFE. Loder RT, Richards BS, Shapiro PS, et al: Acute slipped capital epiphysis: The importance of physeal stability. J Bone Joint Surg Am 1993;75:1134-1140.
Question 1773
Topic: 4. Pediatrics
A 7-year-old boy is seen in the emergency department with an isolated and displaced supracondylar humerus fracture and absent radial and ulnar pulses. Despite a moderately painful attempt at realignment, examination reveals that his hand remains pulseless. What is the next most appropriate step in management?
Correct Answer & Explanation
. Perform closed reduction and pinning in the OR and reassess the vascular status.
Explanation
Displaced supracondylar humerus fractures in children may have associated vascular compromise. Decreased blood flow may be due to vessel injury, entrapment within the fracture site, kinking from fracture displacement, or from vessel spasm. Optimal initial treatment in the emergency department includes gentle realignment of the limb and vascular assessment. Angiography is not required in isolated injuries as the level of the vessel compromise is always at the site of the fracture. When blood flow is not restored, the next best step in treatment is to proceed urgently to the operating room. A formal closed reduction and pinning is performed, and then the vascular status is reassessed. Exploration and vascular repair is required if the hand is cool, white, and without pulses. Ay S, Akinci M, Kamiloglu S, et al: Open reduction of displaced pediatric supracondylar humeral fractures through the anterior cubital approach. J Pediatr Orthop 2005;25:149-153. 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.
Question 1774
Topic: Pediatric Hip
Figure 54 shows the preoperative radiograph of a 45-year-old woman who is considering total hip arthroplasty with her orthopaedic surgeon. What femoral characteristic is a typical concern in this patient?
Correct Answer & Explanation
. Excessive anteversion
Explanation
Developmental dysplasia of the hip (DDH) leads to early arthritis of the hip as seen in this patient. Although DDH is believed to mostly affect the acetabulum, most patients with DDH also have anatomic aberrations of the femur. Using three-dimensional computer models generated by reconstruction of CT scans, dysplastic femurs were shown to have shorter necks and smaller, straighter canals than the controls. The shape of the canal became more abnormal with increasing subluxation. The studies also have shown that the primary deformity of the dysplastic femur is rotational, with an increase in anteversion of 5 degrees to 16 degrees, depending on the degree of subluxation of the hip. The rotational deformity of the dysplastic femur arises within the diaphysis between the lesser trochanter and the isthmus and is not attributable to a torsional deformity of the metaphysis. Osteopenia is not a concern in a patient with an excellent cortical index (thick cortices and narrow canal). Femoral varus or bowing of the femur is not a typical finding in patients with DDH. Noble PC, Kamaric E, Sugano N, et al: Three-dimensional shape of the dysplastic femur: Implications for THR. Clin Orthop 2003;417:27-40.
Question 1775
Topic: Pediatric Hip
A 5-month-old girl with arthrogryposis has a limb-length discrepancy. Examination and radiographs reveal unilateral hip dislocation. Management should consist of
Correct Answer & Explanation
. open reduction.
Explanation
In this age group of patients with arthrogryposis, open reduction through a medial approach is generally recommended. Open reduction through an anterior approach is reserved for patients in which a medial approach has failed or for older patients who require simultaneous femoral shortening and/or pelvic osteotomy. Closed treatment of unilateral hip dislocation in association with arthrogryposis is rarely successful. In bilateral hip dislocation associated with arthrogrypsis, the consensus is that the hips are best left unreduced because of the difficulty in obtaining excellent clinical and radiographic results bilaterally. Staheli LT, Chew DE, Elliot JS, Mosca VS: Management of hip dislocations in children with arthrogryposis. J Pediatr Orthop 1987;7:681-685. Szoke G, Staheli LT, Jaffe K, Hall JG: Medial-approach open reduction of hip dislocation in amyoplasia-type arthrogryposis. J Pediatr Orthop 1996;16:127-130.
Question 1776
Topic: 4. Pediatrics
A pediatric orthopaedic surgeon refers a child to a neurologist. The neurologist's office requests the office records of the pediatric orthopaedic surgeon. To maintain Health Insurance Portability and Accountability Act (HIPAA) compliance, what must the surgeon obtain from the parent(s) prior to sending records?
Correct Answer & Explanation
. No additional consent needed
Explanation
The privacy rules do not require an individual's written authorization for certain permitted or required uses and disclosures of the medical records. Patient or parental authorization is not required for disclosures for certain purposes related to treatment, payment, or health care operations. Specifically, HIPAA does not require a covered entity to obtain patient authorization for many of the health care industry's most fundamental activities such as providing care. Carroll R: Risk Management Handbook for Health Care Organizations, ed 4. Hoboken, NJ, Jossey-Bass, 2003, p 1142.
Question 1777
Topic: 4. Pediatrics
A 9-year-old child sustains a proximal tibial physeal fracture with a hyperextension mechanism. What structure is at most risk for serious injury?
Correct Answer & Explanation
. Popliteal artery
Explanation
The most serious injury associated with proximal tibial physeal fracture is vascular trauma. The popliteal artery is tethered by its major branches near the posterior surface of the proximal tibial epiphysis. During tibial physeal displacement, the popliteal artery is susceptible to injury. Injuries to the other structures are less common.
Question 1778
Topic: 4. Pediatrics
An 11-year-old boy sustained an ankle injury while playing football. Figure 20 shows an AP radiograph obtained the day of injury. Treatment should consist of
Correct Answer & Explanation
. open reduction and internal fixation with fixation parallel to the physis and a non-weight-bearing cast.
Explanation
The child has an injury involving both the growth plate and the articular surface of the ankle. Because of the significant displacement, open reduction and internal fixation is indicated to realign the physis and joint surface. The best method of fixation to avoid growth arrest is one that does not cross the physis. This is usually achieved by a transverse epiphyseal screw parallel to the physis. If the metaphyseal fragment was large enough, a transverse metaphyseal screw could be used instead. The incidence of growth arrest following physeal ankle injuries is as high as 50%, and long-term follow-up is indicated. Cass JR, Peterson HA: Salter-Harris Type-IV injuries of the distal tibial epiphyseal growth plate, with emphasis on those involving the medial malleolus. J Bone Joint Surg Am 1983;65:1059-1070.
Question 1779
Topic: 4. Pediatrics
Figure 39 shows the sagittal T1-weighted MRI scan of a 27-year-old man who twisted his knee 2 weeks ago. The arrow is pointing to
Correct Answer & Explanation
. a physeal scar.
Explanation
The arrow identifies a transverse dark line that represents primary trabeculae of the physeal scar. A similar finding is seen in the proximal tibia. These lines may persist indefinitely. They do not represent ongoing growth, an abnormally open physeal plate, a stress fracture, or Looser's line (fatigue fracture in osteomalacia).
Question 1780
Topic: 4. Pediatrics
An 11-year-old boy has right shoulder pain and has been unwilling to use the arm after throwing a baseball in a Little League game 3 weeks ago. Examination reveals upper arm and shoulder tenderness with swelling. A radiograph and MRI scan are shown in Figures 27a and 27b. Management should consist of
Correct Answer & Explanation
. aspiration and injection with methylprednisolone.
Explanation
The radiograph is consistent with a unicameral (simple) bone cyst. The MRI scan reveals that the cyst is juxtaposed to the physis and therefore can be classified as active (latent cysts are more than 1 cm away from the physis). Active cysts are treated with aspiration and steroid injection, although repeated injections may be necessary. Curettage and bone grafting results in more reliable healing but may lead to growth arrest in active cysts. Iannotti JP, Williams GR: Disorders of the Shoulder: Diagnosis and Management, ed 1. Philadelphia, PA, Lippincott Williams & Wilkins, 1999, pp 945-946.
Test Yourself
Switch to an interactive, timed exam simulation to truly master this topic.
