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 1781
Topic: 4. Pediatrics
A newborn has an anterolateral bow of the tibia and a duplication of the great toe. Which of the following conditions will develop as the infant grows?
Correct Answer & Explanation
. Fracture of the tibia with pseudarthrosis
Explanation
Anterolateral bowing of the tibia is normally associated with congenital pseudarthrosis of the tibia. This, in turn, is associated with neurofibromatosis. Posterior bowing is more benign and usually corrects spontaneously. However, anterolateral bowing also corrects spontaneously, and the limb-length discrepancy may be the only remaining sequela when associated with duplication of the great toe. Lisch nodules and axillary freckling are pathognomonic findings in neurofibromatosis but would not be expected in this patient because this type of tibial deformity is not associated with neurofibromatosis.
Question 1782
Topic: 4. Pediatrics
Figures 16a and 16b show the radiographs of an otherwise healthy 3 1/2-year-old boy who has an isolated deformity of the left leg. Definitive primary treatment of this condition should consist of
Correct Answer & Explanation
. an intramedullary nail and onlay bone graft.
Explanation
Treatment of congenital pseudarthrosis of the tibia is problematic. To achieve union, a resection of the pseudarthrosis, stabilization, and bone grafting must be performed. Simple cast immobilization does not yield union. There are various options for the resection, immobilization, and grafting. On the first surgical attempt, retrograde intramedullary nailing offers the best chance for success by transfixing the ankle and subtalar joints with abundant autogenous bone grafting. Distraction osteogenesis and vascularized free fibular graft are reserved as salvage procedures. Gilbert A, Brockman R: Congenital pseudarthrosis of the tibia: Long-term follow-up of 29 cases treated by microvascular bone transfer. Clin Orthop 1995;314:37-44. Boero S, Catagni M, Donzelli O, Facchini R, Frediani PV: Congenital pseudarthrosis of the tibia associated with neurofibromatosis - 1: Treatment with Ilizarov's device. J Pediatr Orthop 1997;17:675-684.
Question 1783
Topic: 4. Pediatrics
The parents of a 15-month-old child report that he is not yet walking. Further evaluation, rather than reassurance and observation, should be conducted if the child is not performing what other activity?
Correct Answer & Explanation
. Sitting
Explanation
A child not ambulating at age 15 months is still within normal limits. The child should be able to sit by age 9 months. The remaining milestones listed are reached later in development.
Question 1784
Topic: 4. Pediatrics
An 8-year-old boy with moderate factor VIII hemophilia played kickball earlier in the day and now reports progressively severe groin pain and is unable to walk. Examination reveals marked paresthesias over the medial aspect of the distal tibia. What is the most likely diagnosis?
Correct Answer & Explanation
. Hemorrhage into the iliacus muscle
Explanation
The iliacus muscle is a frequent site of hemorrhage in patients with severe or moderate hemophilia. In patients with moderate hemophilia, hemorrhage into the iliacus muscle often follows play or sporting events that include forceful contraction of the hip flexor muscles. An expanding iliacus hematoma compresses the adjacent femoral nerve, with one study reporting 60% complete femoral nerve palsy in hemophiliacs with an iliacus or iliopsoas hemorrhage. Femoral nerve compression typically includes paresthesias in the distribution of the terminal saphenous nerve branch. Hip joint hemarthrosis may occur, but this condition is not as frequent in hemophiliacs as muscle hemorrhage into the iliacus muscle. More importantly, a hip joint hemarthrosis is not associated with significant compression of the femoral nerve. Avulsion fractures of the anterior superior iliac spine typically occur during adolescence and are not associated with saphenous nerve paresthesias. Slipped capital femoral epiphysis does not have an increased association with hemophilia and usually occurs during the adolescent years.
Question 1785
Topic: 4. Pediatrics
A 6-year-old boy with spastic diplegic cerebral palsy has a crouched gait. Examination reveals hip flexion contractures of 15 degrees and popliteal angles of 70 degrees. Equinus contractures measure 10 degrees with the knees extended. Which of the following surgical procedures, if performed alone, will worsen the crouching?
Correct Answer & Explanation
. Hamstring lengthening
Explanation
Children with spastic diplegic cerebral palsy often have contractures of multiple joints. Because the gait abnormalities can be complex, isolated surgery is rarely indicated. To avoid compensatory deformities at other joints, it is preferable to correct all deformities in a single operation. Isolated heel cord lengthening in the presence of tight hamstrings and hip flexors will lead to progressive flexion at the hips and knees, thus worsening a crouched gait. Split posterior tibial tendon transfer is used for patients with hindfoot varus, which is not present in this patient. Gage JR: Distal hamstring lengthening/release and rectus femoris transfer, in Sussman MD (ed): The Diplegic Child. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1992, pp 324-326.
Question 1786
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
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. Kocher MS: Ghost surgery: The ethical and legal implications of who does the operation. J Bone Joint Surg Am 2002;84:148-150.
Question 1787
Topic: Pediatric Hip
Figure 10 shows the radiograph of a 7-year-old patient who has a bilateral Trendelenburg limp and limited range of hip motion but no pain. His work-up should include
Correct Answer & Explanation
. a skeletal survey.
Explanation
The radiograph shows bilateral flattening of the femoral heads with mottling and "fragmentation" suggestive of Legg-Calve-Perthes disease. However, when these changes occur bilaterally and are symmetric, multiple epiphyseal dysplasia or spondyloepiphyseal dysplasia should be suspected. Skeletal survey will show irregularity of the secondary ossification centers. With these conditions, there is no true osteonecrosis and no evidence that orthotic or surgical "containment" will alter the outcome of progressive degenerative arthritis. Cardiac anomalies and coagulopathies are not associated with the epiphyseal dysplasias. Crossan JF, Wynne-Davies R, Fulford GE: Bilateral failure of the capital femoral epiphysis: Bilateral Perthes disease, multiple epiphyseal dysplasia, pseudoachondroplasia, and spondyloepiphyseal dysplasia congenita and tarda. J Pediatr Orthop 1983;3:297-301.
Question 1788
Topic: 4. Pediatrics
Figure 39 shows the radiograph of a 4-month old infant who has been undergoing weekly casting since birth for a congenital equinovarus deformity. Management should now consist of
Correct Answer & Explanation
. surgical correction.
Explanation
The radiograph shows the development of a rocker-bottom foot deformity. A rocker-bottom foot occurs in the treatment of clubfoot when casting is continued in the presence of a very tight gastrocnemius-soleus complex and an uncorrected hindfoot. While there are some preliminary reports on using Botox injection and continued casting for the equinus deformity, most authors recommend posterior or posterior medial release. Percutaneous tenotomy has been recently recommended with the resurgence of the Ponsetti technique. Lehman WB, Atar D: Complications in the management of talipes equinovarus, in Drennan JC (ed): The Child's Foot and Ankle. New York, NY, Raven Press, 1992, pp 135-136. Herring JA: Tachdjian's Pediatric Orthopedics, ed 4. Philadelphia, PA, WB Saunders, 2002, pp 927-935.
Question 1789
Topic: Pediatric Lower Extremity
A 5-year-old boy has had midfoot pain with activity for the past 3 months. He has no pain at rest. Radiographs are shown in Figures 29a and 29b. Management should consist of
Correct Answer & Explanation
. a short leg walking cast.
Explanation
The radiographs show classic findings for Koehler's disease (osteochondrosis of the navicular). The patient's age and clinical history are typical for this self-limiting condition. Patients will improve with time, but the duration of symptoms is much shorter if the patient is placed in a cast. There is no role for surgery in this disease.
Question 1790
Topic: 4. Pediatrics
A 10-year-old girl with a monoarticular pattern of juvenile rheumatoid arthritis (JRA) has had a 3-cm limb-length discrepancy since age 8 years when inflammation in the right knee came under good medical control. Because her right leg is longer, the patient states that she would like her legs to be close to equal in length in the future. A growth-remaining chart is shown in Figure 14. Management should consist of
Correct Answer & Explanation
. observation with the expectation that the discrepancy may correct itself and not require surgery.
Explanation
In a subgroup of patients with monoarticular JRA and a limb-length discrepancy that developed before the age of 9 years, Simon and associates showed that a subsequent growth deceleration on the affected side may correct a large part of the difference in length. This possibility would make surgery unnecessary and should prompt further observation. Simon S, Whiffen J, Shapiro F: Leg-length discrepancies in monoarticular and pauciarticular juvenile rheumatoid arthritis. J Bone Joint Surg Am 1981;63:209-215.
Question 1791
Topic: Pediatric Hip
A 7-year-old patient has had a painless limp for several months. Examination reveals pain and spasm with internal rotation, and abduction is limited to 10 degrees on the involved side. Management consists of 1 week of bed rest and traction, followed by an arthrogram. A maximum abduction/internal rotation view is shown in Figure 40a, and abduction and adduction views are shown in Figures 40b and 40c. The studies are most consistent with
Correct Answer & Explanation
. hinge abduction.
Explanation
The radiographs show classic hinge abduction. The diagnostic feature is the failure of the lateral epiphysis to slide under the acetabular edge with abduction, and the abduction view shows medial dye pooling because of distraction of the hip joint. Persistent hinge abduction has been shown to prevent femoral head remodeling by the acetabulum. Radiographic changes are characteristic of severe involvement with Legg-Calve-Perthes disease. The Catterall classification cannot be well applied without a lateral radiograph, but this degree of involvement would likely be considered a grade III or IV. Because the lateral pillar is involved, this condition would be classified as type C using the Herring lateral pillar classification scheme.
Question 1792
Topic: Pediatric Hip
Figure 26 shows the radiograph of an otherwise healthy Caucasian 5-year-old boy who has a painless limp. What is the best treatment option?
Correct Answer & Explanation
. Physical therapy and range-of-motion exercises
Explanation
The prognosis of Legg-Perthes disease in children younger than age 6 years is good. There is no indication that surgical treatment will improve the outcome. Range-of-motion exercises to prevent contracture may be helpful. Herring JA, Kim HT, Browne R: Legg-Calve-Perthes disease: Prospective multicenter study of the effect of treatment on outcome. J Bone Joint Surg Am 2004;86:2121-2134.
Question 1793
Topic: Pediatric Hip
Figures 20a and 20b show the radiographs of an obese 15-year-old boy who has severe left groin pain and is unable to bear weight following a minor injury. Treatment should consist of
Correct Answer & Explanation
. in situ fixation with multiple screws.
Explanation
The radiographs and history are consistent with an acute unstable slipped capital femoral epiphysis. Aronson and Loder documented an increased rate of osteonecrosis associated with manipulative reduction. They recommended bed rest with skin traction to allow the synovitis to resolve, followed by in situ pinning. They noted, however, that many of these slips reduced with anesthesia and positioning on a fracture table. Biomechanic studies have shown a slight increased resistance to shear stress when two screws are used, but it is unknown if this is significant in the clinical setting. Open epiphyseodesis does not provide postoperative stability; therefore, adjunctive fixation or immobilization is required. Numerous studies have noted the inadvisability of using multiple screws. Casting has a high rate of complications, including chondrolysis and progression of the slip. Aronson DD, Loder RT: Treatment of the unstable (acute) slipped capital femoral epiphysis. Clin Orthop 1996;322:99-110. Karol LA, Doane RM, Cornicelli SF, Zak PA, Haut RC, Manoli A II: Single versus double screw fixation for treatment of slipped capital femoral epiphysis: A biomechanical analysis. J Pediatr Orthop 1992;12:741-745.
Question 1794
Topic: 4. Pediatrics
The mother of an otherwise healthy 1-month-old infant reports that he is not moving his left leg after falling from his high chair 2 days ago. He has a temperature of 99.5 degrees F (37.5 degrees C). Examination reveals that the left thigh is moderately tender to palpation. Because the infant is apprehensive, range of motion is difficult to quantify, but appears to be normal at the hips and ankles. Range of motion of the left knee is approximately 25 degrees to 90 degrees. A radiograph of the leg is shown in Figure 27. Management should consist of
Correct Answer & Explanation
. application of a long leg splint and admission to the hospital for further evaluation and consultation.
Explanation
The patient has a bucket-handle fracture of the distal femur with bilateral corner fractures of the distal femur and a transverse fracture of the proximal tibia. These fractures are virtually pathognomonic of child abuse. The infant should be admitted to the hospital, and child protection services should be notified for investigation of possible abuse. A skeletal survey should be obtained, along with laboratory studies that include a CBC, a platelet count, a prothrombin time, a partial thromboplastin time, and a bleeding time. Akbarnia BA: The role of the orthopaedic surgeon in child abuse, in Morrissy RT, Weinstein SL (eds): Lovell & Winter's Pediatric Orthopaedics, ed 4. Philadelphia, Pa, Lippincott-Raven, 1996, pp 1315-1334.
Question 1795
Topic: 4. Pediatrics
A 14-year-old football player has had right knee pain for the past 2 months; however, he denies any history of trauma. Examination shows an abductor lurch and increased external rotation of the right lower extremity. The best course of action should be to
Correct Answer & Explanation
. obtain AP and frog-lateral radiographs of the pelvis.
Explanation
Slipped capital femoral epiphysis is the most common pathology involving the hip in adolescents. While patients with acute slips may report severe pain and are unable to ambulate, those with chronic slips often have pain during ambulation, a limp, and increased external rotation of the hip. While 60% of the patients specifically report hip pain, the remainder have pain in the thigh or knee. The initial diagnostic study of choice is AP and frog-lateral radiographs of the pelvis; bilateral involvement is frequently seen. Boyer DW, Mickelson MR, Ponseti IV: Slipped capital femoral epiphysis: Long-term follow-up study of one hundred and twenty-one patients. J Bone Joint Surg Am 1981;63:85-95.
Question 1796
Topic: 4. Pediatrics
The mother of a 24-month-old girl reports that the child cannot rotate her right forearm. She also notes delayed development, with the child first walking at 18 months. The child has a five-word vocabulary and has not begun using simple phrases. Examination reveals that the right forearm is fixed in 80 degrees of pronation. The remainder of the examination of both upper extremities is otherwise normal. A radiograph is shown in Figure 41. Which of the following studies will best aid in diagnosis?
Correct Answer & Explanation
. Chromosome analysis
Explanation
The patient has classic radioulnar synostosis. Patients with this disorder frequently have duplication of sex chromosomes. Synostosis is often seen in females with 48-XXXX or 49-XXXXX in association with delayed development and mental retardation.
Question 1797
Topic: 4. Pediatrics
A 7-year-old girl sustains the fracture shown in Figure 29a. Casting results in uneventful healing. Ten months later, the patient has a progressive valgus deformity of the right lower extremity. A radiograph is shown in Figure 29b. Management should now consist of
Correct Answer & Explanation
. observation.
Explanation
Although fractures of the proximal tibial metaphysis in young children appear innocuous, development of a progressive valgus deformity is possible despite adequate and appropriate treatment. When treating a child with this injury, it is prudent to warn the parents that a valgus deformity of the tibia may develop. The most likely cause is asymmetric growth of the proximal tibial physis. Because spontaneous angular improvement can be expected in most patients, surgery to correct these deformities should be delayed at least 2 to 3 years and should be limited to patients who have symptoms. There are no studies that document the efficacy of bracing for this deformity. Tuten HR, Keeler KA, Gabos PG, et al: Posttraumatic tibia valga in children: A long-term follow-up note. J Bone Joint Surg Am 1999;81:799-810.
Question 1798
Topic: 4. Pediatrics
Examination of an obese 3-year-old girl reveals 30 degrees of unilateral genu varum. A radiograph of the involved leg with the patella forward is shown in Figure 10. Management should consist of
Correct Answer & Explanation
. proximal tibiofibular osteotomy and acute correction.
Explanation
The clinical scenario describes infantile tibia vara (Blount's disease). The radiograph shows severe deformity with the characteristic Langenskiold stage 3 changes of the medial proximal tibial metaphysis that distinguish it from physiologic bowing. The preferred treatment is proximal tibiofibular osteotomy with acute correction into slight valgus to unload the damaged area of the physis. This method provides the best results in patients younger than age 4 years. Continued observation would result in progressive deformity. Bracing is most effective in younger children with less severe deformity. Lateral proximal tibial hemiepiphysiodesis relies on growth of the injured medial physis for correction and would result in severe tibial shortening in this young child. Complete epiphysiodesis also produces severe shortening and requires multiple lengthening procedures. Johnston CE II: Infantile tibia vara. Clin Orthop 1990;255:13-23.
Question 1799
Topic: Pediatric Hip
A 15-year-old girl who swims the breaststroke has had hip pain after training excessively for a national level competition. Based on the MRI scans shown in Figures 5a through 5c, what is the most likely diagnosis?
Correct Answer & Explanation
. External rotator muscle tear
Explanation
The MRI scans reveal open physes but no evidence of a slipped capital femoral epiphysis, labral tear, or acetabular dysplasia. The femoral neck does not show evidence of a fracture. The muscle tear seen on the right side lies near the musculotendinous junction of the external rotators of the hip at the level of the lesser trochanter, representing the obturator externus. This is consistent with the forced motion required for the breaststroke kick. Grote K, Lincoln TL, Gamble JG: Hip adductor injury in competitive swimmers. Am J Sports Med 2004;32:104-108.
Question 1800
Topic: 4. Pediatrics
A 4-year-old boy sustained a nondisplaced, but complete, fracture of the left proximal tibial metaphysis 1 year ago. The fracture healed uneventfully in an anatomic position. Examination of the injured extremity now reveals 18 degrees of valgus compared with 3 degrees of valgus on the opposite side. Management should now include
Correct Answer & Explanation
. observation.
Explanation
The development of a valgus deformity after this type of fracture is a well-known occurrence, and the patient's parents should be informed about this risk. In a patient who is age 4 years, the natural history is one of gradual correction by the development of a physiologic varus deformity at the distal tibial physis; therefore, no active intervention is needed at this time. Bracing has no effect on the deformity, and the child is too young for any procedure on the growth plate. Proximal tibial osteotomy is reserved until the patient nears skeletal maturity because of the risk of recurrence of the deformity. Lateral stapling can be done near skeletal maturity if the deformity persists, but this is unlikely to be necessary. Zionts LE, MacEwen GD: Spontaneous improvement of posttraumatic tibia valga. J Bone Joint Surg Am 1986;68:680-687.
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