Question 1

At which age do patients most commonly present with dysplasia epiphysialis hemimelia (DEH):

Explanation

Most cases of DEH occur in patients between early childhood and early teen years. Dysplasia epiphysialis hemimelia does not present at birth.C orrect Answer: Between early childhood and early teen years

Question 2

This radiograph (Slide) shows an 11-month-old girl with a Tonnis 3 developmental dislocation of the hip. Recommended treatment includes:

Explanation

Orthopedic Prometric Exam Chapter 3 Image

Closed reduction and spica cast application is the best treatment for this patient with a Tonnis 3 developmental dislocation of the hip. Open reduction and spica cast application introduces additional risks of infection and vascular compromise and should not be performed unless closed reduction and spica cast application fails. This patient is too old to be controlled by a Pavlik harness.

Question 3

The mechanical axis of the lower extremity is defined as the angle formed by lines drawn from the center of the hip to the center of the knee to the center of the ankle. The resulting value should be:

Explanation

The mechanical axis should be 0°. Alignment following correctional osteotomies and arthroplasties must re-establish the mechanical axis.

Question 4

A 2-year-old boy presents with intoeing. An examination shows that his feet form an angle of 20° inward with the direction he is walking. Which of the following parameters describes his condition:

Explanation

The 20° inward angle formed with the direction the patient is walking is a foot progression angle. This angle encompasses all factors influencing position and progression of the lower extremity during gait.

Question 5

Which of the following measurements reflects the mean lateral distal femoral joint angle with respect to the mechanical axis:

Explanation

The lateral distal femoral angle with respect to the mechanical axis is 87°.

Question 6

A 2-year-old patient presents with bowed legs. The metaphyseal diaphyseal angle is 17°, and the mechanical axis shows 15° of varus bilaterally. The varus appears to be in the proximal tibia. No evidence of metabolic disease or dysplasia is present. Recommended treatment inlcudes:

Explanation

This patient has infantile Blount disease. Brace treatment is appropriate to try, although it is not always successful. The best treatment is for the patient to wear a knee-ankle-foot brace full-time. High tibial osteotomy, medial staple hemiepiphysiodesis, and percutaneous hemiepiphysiodesis are inappropriate treatments for this patient at 2 years old. If the varus does not improve by the time the patient is 3.5 years old to 4 years old, then high tibial osteotomy should be performed.

Question 7

A newborn infant presents with a knee complication. The patientâ s knee hyperextends to 30° and flexes to 30°. The neurovascular examination is normal, and the patientâ s hips are stable. No other skeletal complications are found. Radiographs show a line along the axis of the tibia intersecting the ossific nucleus of the distal femur, signaling significant hyperextension. Recommended treatment inlcudes:

Explanation

This patient has a hyperextensible, but not dislocated, knee. In the radiograph, the line along the axis of the tibia would intersect the femur anterior to the ossific nucleus if the patientâ s knee were dislocated. Hyperextensible knee is an in utero complication and resolves without treatment.

Question 8

A 12-year-old girl has genu valgum and requests correction. Radiographs reveal 12° valgus of the mechanical axis, with 2° arising in the distal femur and 3° arising in the proximal tibia. No evidence of other disorders are present. Recommended treatment includes:

Explanation

This patient has a significant amount of valgus. Valgus at the knee is evident when signaled by even a low number of degrees. The patient is at an age when medial distal femur staple hemiepiphysiodesis would be the best treatment for genu valgum. Medial distal femur staple hemiepiphysiodesis is a safe and effective procedure and is performed using small incisions, which allow for immediate ambulation.

Question 9

Which of the following conditions is not part of the differential diagnosis of a valgus knee in a 4-year-old child:

Explanation

Physiologic valgus, prior proximal metaphyseal fracture, multiple exostoses, and chondroectodermal dysplasia produce valgus. Infantile Blount disease produces varus.

Question 10

Which of the following methods of treatment has the lowest success rate in treating patients with congenital pseudarthrosis of the tibia:

Explanation

Electromagnetic stimulation has the lowest success rate in treating patients with congenital pseudarthrosis of the tibia. Vascularized fibula graft, Ilizarovâ s method, IM rod fixation and bone graft, and Ilizarovâ s method over an intramuscular rod have similar success rates.

Question 11

Which of the following methods of measuring limb length inequality includes the greatest number of factors leading to pelvic height difference:

Explanation

The block method consists of adding height to the short limb in blocks until the pelvis is level. The block method measures differences in foot height and pelvic size as well as inequalities of the long bones. Because the teleroentgenogram shows the whole limb in one exposure, the exposure is susceptible to be parallax and distorted at the ends. The orthoroentgenogram and scanogram measure limb length inequality similarly, but the scanogram captures only the joints and eliminates the diaphyses.

Question 12

A patient with myelomeningocele is a community ambulator. She has a minimal Trendelenburgâ s sign but has a calcaneus gait. Her motor level is:

Explanation

A calcaneus gait describes heel strike with no pushoff. This patient has active anterior tibialis with no gastrocsoleus. The Trendelenburgs test shows that her gluteals are minimal at less than L4. The patientâ s motor level is L5.

Question 13

An 8-year-old child with spina bifida has a focal kyphosis measuring 100Â° with an apex at the first lumbar vertebra and a short trunk. The patients family is concerned about the childâ s risk of skin breakdown posteriorly. Recommended treatment includes:

Explanation

This patient has myelokyphosis, which occurs in some patients with a thoracic level of spina bifida. The myelokyphosis is caused by a lack of posterior spinal osteoligamentous elements and denervated musculature and has a sharp, single apex with a compensatory lordosis above and below the apex. Myelokyphosis is steadily progressive with growth. Bracing and casting are ineffective treatments for patients with myelokyphosis due to the focality of the complication and insufficient skin coverage over the apex. Posterior fusion in situ is mechanically ineffective in controlling the large focal curve occurring in myelokyphosis. Anterior strut grafting in a growing child functions as an anterior bar that exacerbates the patientâ s myelokyphosis. A kyphectomy is the best treatment for a patient with myelokyphosis. A kyphectomy entails a posterior resection of the apical vertebra and posterior instrumentation. Posterior instrumentation corrects the cantilever. A kyphectomy does not entail fusion beyond the resected area because such a fusion impedes growth.

Question 14

This is a radiograph of a patient with myelomeningocele. At which of the following levels is the lesion located:

Explanation

This patient has active quadriceps (which are innervated through L2-L4) and adductors (which are innervated through L1-L3). Because the patientâ s knees are slightly hyperextended there is no hamstring function. The patientâ s right foot has some dorsiflexion. The lesion is rated as L4. However, the patientâ s right side may be rated as L3.

Question 15

A 1-year-old patient with L4 myelomeningocele presents with a foot complication. Radiographs are shown in neutral plantarflexion (Slide 1) and in maximal plantarflexion (Slide 2). Recommended treatment includes:

Orthopedic Prometric Exam Chapter 3 Image

Explanation

This patient has a congenital vertical talus, also known as a congenital dorsolateral dislocation of the talonavicular joint. Because the navicular is not yet ossified, the dorsal position of the first metatarsal line illustrates evidence of the patients congenital vertical talus when compared to the position of the talus. The congenital vertical talus is fixed because it does not become reduced upon maximum plantarflexion. The best treatment for congenital vertical talus is open reduction of the congenital talonavicular dislocation, with tendon lengthening.

Question 16

An 8-year-old girl with myelomeningocele has sustained warmth and swelling of her leg for 2 weeks. She does not recall any trauma. She has had a temperature of 101° on several occasions. Her radiograph (Slide) is shown below. The most likely diagnosis is:

Explanation

This patient has a Salter 1 physeal fracture of the distal tibia, which was probably caused by stress that remained unrecognized due to the patientâ s lack of pain. Patients with spina bifida experience extensive periosteal reaction because they do not get early immobilization.

Question 17

This radiograph (Slide) shows a 5-year-old boy with an L4 myelomeningocele. He can ambulate with a walker. Recommended treatment includes:

Orthopedic Prometric Exam Chapter 3 Image

Explanation

This patient has symmetrical high, longstanding dislocations. Because his level is L4, he has no abductor function. The patient has multiple contraindications to surgery, including current symmetry, lack of abduction power, young age, and an inability to walk without a walker. His ability to walk would likely be hindered by surgery.

Question 18

The first radiograph (Slide 1) shows the pelvis of a patient with L3 myelomeningocele at 9 years old. The second radiograph (Slide 2) shows the pelvis of the same patient taken 2 years later. Which of the following factors most likely contributed to the change in the patientâ s pelvis:

Orthopedic Prometric Exam Chapter 3 Image

Explanation

Note that the radiograph in Slide 1 shows normal hip joints, and the radiograph in Slide 2, which was taken 2 years later, shows symmetric dislocation. This patient has a tethered cord. The tethered cord caused increased spasticity, resulting in the spontaneous dislocation of the patient's hips during the 2 years between the time the two radiographs were taken.

Question 19

In which of the following molecules is McC une-Albrightâ s syndrome due to a mutation:

Explanation

McC une-Albrights syndrome (also known as polyostotic fibrous dysplasia) is due to a mutation in GNAS1. GNAS1 is the alpha subunit of GS, which is a protein that links receptors to adenyl cyclase activity.

Question 20

Which of the following symptoms is not characteristic of McC une- Albrights syndrome:

Explanation

The cafa-au-lait spots associated with McC une-Albrightâ s syndrome are described as â coast of Maineâ spots because they have irregular borders. The cafÃ©-au-lait spots associated with neurofibromatosis are described as â coast of C aliforniaâ spots because they have smooth borders.

Question 21

A 4-month-old infant with developmental dysplasia of the hip has been managed in a Pavlik harness for 4 weeks with no ultrasound evidence of reduction. What is the next best step in management?

Explanation

If a Pavlik harness fails to achieve reduction within 3 to 4 weeks, it should be discontinued to avoid 'Pavlik harness disease' (posterior wear of the acetabulum). The next appropriate step is closed reduction and spica casting under general anesthesia.

Question 22

Dysplasia epiphysialis hemimelia (Trevor disease) is a rare developmental disorder of the epiphysis. Histologically, the lesions of Trevor disease most closely resemble which of the following?

Explanation

Trevor disease is characterized by asymmetric epiphyseal cartilage overgrowth. Histologically, it is identical to an osteochondroma, displaying a hyaline cartilage cap with underlying enchondral ossification.

Question 23

In analyzing coronal plane alignment of the lower extremity, the mechanical axis of the femur differs from its anatomical axis. In a typical normal adult, what is the approximate angle between the mechanical and anatomical axes of the femur?

Explanation

The anatomical axis of the femur lies approximately 7 degrees (usually 5-7 degrees) in valgus relative to its mechanical axis. This angle is vital for preoperative planning in deformity correction and arthroplasty.

Question 24

A 12-year-old overweight boy presents with sudden inability to bear weight on his right leg after a minor fall. Radiographs show a slipped capital femoral epiphysis (SCFE). According to the Loder classification, what is the most significant risk associated with this specific presentation?

Explanation

The inability to bear weight even with crutches defines an unstable SCFE according to the Loder classification. Unstable slips carry a significantly higher risk of avascular necrosis (up to 47%) compared to stable slips.

Question 25

A 24-month-old girl presents with bilateral lower extremity bowing. Which of the following radiographic measurements is most predictive of infantile Blount disease rather than physiologic bowing?

Explanation

A metaphyseal-diaphyseal angle (Drennan angle) greater than 16 degrees on an AP radiograph strongly suggests infantile Blount disease. Angles less than 10 degrees are typically physiologic, while 10-16 degrees represent a gray zone requiring observation.

Question 26

In a patient with Legg-Calvé-Perthes disease, the Herring lateral pillar classification is used for prognosis. Which of the following describes a Herring Group B classification?

Explanation

In the Herring classification, Group B indicates that the lateral pillar maintains >50% of its normal height. Group C indicates <50% height maintained, which corresponds to a worse prognosis and a higher risk of aspherical head development.

Question 27

During the correction of idiopathic clubfoot using the Ponseti method, the deformities are addressed in a specific sequence. Which deformity is corrected last?

Explanation

The Ponseti method corrects clubfoot deformities in the CAVE sequence: Cavus, Adductus, Varus, and finally Equinus. Correction of equinus usually requires a percutaneous Achilles tenotomy as the final step.

Question 28

A 6-week-old female infant undergoes a screening ultrasound for developmental dysplasia of the hip (DDH). What is the minimum normal alpha angle according to the Graf classification?

Explanation

In the Graf classification for developmental dysplasia of the hip, an alpha angle of 60 degrees or greater indicates a mature, normal hip (Type I). The alpha angle measures the bony acetabular roof depth.

Question 29

A 5-year-old boy falls on an outstretched hand and sustains a widely displaced extension-type supracondylar humerus fracture. Which nerve is most commonly injured in this specific fracture pattern?

Explanation

The anterior interosseous nerve (AIN), a branch of the median nerve, is the most commonly injured nerve in extension-type supracondylar humerus fractures. Its function is assessed by asking the patient to make an 'OK' sign.

Question 30

A 4-year-old child with developmental coxa vara is being evaluated for surgical intervention. Which of the following radiographic parameters is generally accepted as an indication for a valgus producing proximal femoral osteotomy?

Explanation

A Hilgenreiner-epiphyseal angle (HEA) greater than 60 degrees is a classic indication for surgical correction (valgus osteotomy) in developmental coxa vara. An HEA less than 45 degrees usually resolves spontaneously or does not progress.

Question 31

A 7-year-old girl is diagnosed with Klippel-Feil syndrome. Because of the known systemic associations with this condition, which of the following screening tests should be routinely ordered?

Explanation

Klippel-Feil syndrome is defined by congenital fusion of two or more cervical vertebrae. Approximately 30% of these patients have associated genitourinary anomalies, making a screening renal ultrasound an essential step.

Question 32

An infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During a follow-up visit, the infant is noted to lack active knee extension on the treated side. Which of the following is the most likely cause?

Explanation

Hyperflexion of the hip in a Pavlik harness (typically >120 degrees) can compress the femoral nerve against the pubis, leading to femoral nerve palsy and loss of active knee extension. The harness must be adjusted to reduce flexion.

Question 33

A 7-year-old boy is diagnosed with Legg-Calvé-Perthes Disease (LCPD). Radiographs demonstrate that less than 50% of the lateral pillar height is maintained. According to the Herring classification, which type does this represent and what is the expected outcome?

Explanation

Herring Type C is defined by the lateral pillar maintaining less than 50% of its original height. This indicates severe collapse and is associated with a poor prognosis, often leading to early osteoarthritis.

Question 34

A 12-year-old obese boy presents with acute-on-chronic Slipped Capital Femoral Epiphysis (SCFE) and is unable to bear weight even with crutches (unstable SCFE). What is the most significant complication he is at risk for following in situ pinning?

Explanation

Unstable SCFE carries a significantly higher risk of avascular necrosis (up to 47%) compared to stable SCFE. Urgent but careful reduction and stabilization are critical to minimize this risk.

Question 35

An infant with a severe clubfoot is undergoing serial casting using the Ponseti method. After four casts, the midfoot rotation is corrected, the heel is in valgus, and the talonavicular joint is reduced, but the foot remains in 15 degrees of equinus. What is the most appropriate next step in management?

Explanation

Once the cavus, adductus, and varus deformities are corrected and the talonavicular joint is reduced, residual equinus is treated with a percutaneous Achilles tenotomy followed by a final cast in dorsiflexion.

Question 36

A 3-year-old girl presents with progressive bilateral bowing of the legs. Radiographs reveal a metaphyseal-diaphyseal angle (Drennan angle) of 18 degrees with early medial metaphyseal beaking. What is the most appropriate initial management?

Explanation

A Drennan angle >16 degrees strongly suggests infantile Blount's disease. For a child under 3 to 4 years old in early Langenskiöld stages (I-II), KAFO bracing during weight-bearing is the standard initial treatment.

Question 37

A 14-year-old athlete presents with recurrent ankle sprains and a rigid, painful flatfoot. Lateral radiographs of the foot demonstrate a continuous bony bridge between the talus and calcaneus appearing as a "C-sign". Which tarsal coalition is most likely present?

Explanation

The radiographic "C-sign" on a lateral view of the ankle/foot is highly specific for a talocalcaneal (subtalar) coalition. Calcaneonavicular coalitions typically show the "anteater nose" sign on an oblique view.

Question 38

In a child with spastic quadriplegic Cerebral Palsy (GMFCS Level V), hip surveillance is critical. Which radiographic threshold is generally accepted as an absolute indication for prophylactic soft tissue or bony surgical intervention to prevent dislocation?

Explanation

A Reimers migration index >30% to 40% in a non-ambulatory child with severe CP often warrants surgical intervention (like adductor release or VDRO) due to the high risk of progressive, painful hip dislocation.

Question 39

A 5-year-old child with multiple fractures, blue sclerae, and dentinogenesis imperfecta is diagnosed with Osteogenesis Imperfecta. This condition is primarily caused by a mutation affecting the synthesis of which type of collagen?

Explanation

Osteogenesis Imperfecta is predominantly caused by mutations in the COL1A1 or COL1A2 genes, which lead to quantitative or qualitative defects in Type I collagen, the major structural protein in bone.

Question 40

A 6-year-old falls on an outstretched hand, sustaining a completely displaced supracondylar humerus fracture. If the distal fragment is displaced posteromedially, which neurovascular structure is at highest risk of injury?

Explanation

In a posteromedially displaced supracondylar fracture, the proximal fragment spikes anterolaterally, putting the radial nerve at the greatest risk of tethering or injury.

Question 41

A 13-year-old girl sustains an ankle injury. Radiographs show a Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis. What ligament is responsible for avulsing this fragment?

Explanation

This describes a juvenile Tillaux fracture. It occurs due to avulsion by the anterior inferior tibiofibular ligament (AITFL) as the distal tibial physis closes in an asymmetrical pattern (central, then medial, then lateral).

Question 42

Congenital pseudarthrosis of the tibia (CPT) presents with anterolateral bowing of the tibia and subsequent fracture that fails to heal. This condition is most strongly associated with which underlying systemic disorder?

Explanation

Approximately 50% of children presenting with congenital pseudarthrosis of the tibia have an underlying diagnosis of Neurofibromatosis Type 1 (NF1).

Question 43

A 9-year-old child complains of a painful "snapping" sensation in the lateral knee. MRI reveals a Wrisberg variant discoid meniscus. What anatomical feature characterizes this specific variant?

Explanation

The Wrisberg variant of a discoid lateral meniscus lacks normal posterior meniscotibial (coronary) ligaments. Its only posterior attachment is the ligament of Wrisberg, leading to hypermobility and the classic "snapping" knee.

Question 44

A 12-year-old elite baseball pitcher complains of vague shoulder pain during the late cocking phase of throwing. Radiographs demonstrate widening of the proximal humeral physis. What is the most appropriate initial management?

Explanation

Little League Shoulder (proximal humeral epiphysiolysis) is a stress-related injury. The definitive initial treatment is absolute cessation of throwing (usually for 3 months) until symptoms resolve and radiographs normalize.

Question 45

An 11-year-old boy presents with knee pain. MRI reveals an osteochondritis dissecans (OCD) lesion on the lateral aspect of the medial femoral condyle. The physis is open, and there is no fluid behind the lesion, indicating it is stable. What is the best initial treatment?

Explanation

Juvenile OCD lesions (open physes) that are stable on MRI have an excellent prognosis for spontaneous healing. Initial treatment consists of activity modification and restricted weight-bearing.

Question 46

Infants diagnosed with achondroplasia are at an increased risk of sudden death or severe central sleep apnea during the first year of life. This life-threatening complication is primarily due to:

Explanation

Foramen magnum stenosis is a critical complication in achondroplasia. It can cause cervicomedullary compression, leading to central sleep apnea, hyperreflexia, or sudden infant death, necessitating screening and possible surgical decompression.

Question 47

A 10-year-old girl has a leg length discrepancy. Using the multiplier method, her projected discrepancy at skeletal maturity is calculated to be 3.5 cm. Assuming a normal, stable hip and knee, what is the most appropriate surgical management?

Explanation

Projected leg length discrepancies between 2.0 and 5.0 cm at maturity are typically best managed with a properly timed contralateral epiphysiodesis to halt growth on the longer leg.

Question 48

A newborn presents with a rigid, rocker-bottom foot deformity. Radiographs demonstrate the navicular articulating with the dorsal aspect of the talar neck. This dislocation does not reduce on a maximum plantarflexion lateral radiograph. What is the diagnosis?

Explanation

A rigid dorsal dislocation of the navicular on the talus that fails to reduce with forced plantarflexion is the pathognomonic radiographic finding of congenital vertical talus (CVT). An oblique talus would reduce on plantarflexion.

Question 49

Which of the following clinical scenarios most strongly indicates the need for prophylactic in situ pinning of the contralateral hip in a patient presenting with unilateral Slipped Capital Femoral Epiphysis (SCFE)?

Explanation

Patients with underlying endocrinopathies, metabolic disorders, or those undergoing radiation therapy have an extremely high rate of bilateral SCFE (up to 100%), making prophylactic pinning of the contralateral hip highly recommended.

Question 50

What is the primary mechanism of injury leading to a medial epicondyle avulsion fracture in a pediatric patient?

Explanation

Medial epicondyle fractures typically result from an acute valgus stress coupled with a forceful contraction of the flexor-pronator muscle mass, often seen in throwing sports or falls on an outstretched hand.

Question 51

An 8-year-old boy with Legg-Calvé-Perthes disease presents with a painless limp. Which of the following radiographic findings is considered a Catterall "head-at-risk" sign, indicating a poorer prognosis?

Explanation

Gage's sign (a V-shaped radiolucency in the lateral portion of the epiphysis/metaphysis), lateral subluxation, horizontal physis, and diffuse metaphyseal cysts are classic Catterall "head-at-risk" signs that correlate with poor outcomes.

Question 52

An obese 13-year-old boy presents with left knee pain and an antalgic gait. Radiographs demonstrate a displaced slipped capital femoral epiphysis (SCFE).

What is the most appropriate initial treatment for a stable, moderate SCFE?

Explanation

In situ fixation with a single cannulated screw placed in the center of the epiphysis is the gold standard for stable SCFE to prevent further slip. Closed reduction increases the risk of avascular necrosis and should be avoided.

Question 53

A 4-month-old female with developmental dysplasia of the hip is being treated with a Pavlik harness. During a follow-up visit, she is noted to have decreased active extension of the knee on the affected side. What is the most likely cause of this finding?

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment caused by excessive hip flexion. The harness should be adjusted or temporarily discontinued until nerve function recovers.

Question 54

A 3-year-old obese child presents with bilateral bowing of the lower extremities.

Radiographs show prominent medial metaphyseal beaking and an abnormal metaphyseal-diaphyseal angle of 18 degrees. Which of the following is the most appropriate management?

Explanation

For early-onset (infantile) Blount disease in a child under 4 years of age with Langenskiöld stage I-II, KAFO bracing is indicated. Surgery is reserved for older children, failure of bracing, or advanced stages.

Question 55

A 14-year-old boy presents with frequent ankle sprains and rigid flatfeet. A CT scan confirms a calcaneonavicular coalition covering less than 50% of the joint surface, with no arthritic changes. Initial conservative management has failed. What is the recommended surgical intervention?

Explanation

For a symptomatic calcaneonavicular coalition covering less than 50% of the joint without degenerative changes, resection of the coalition with interposition of the extensor digitorum brevis (EDB) or fat is the treatment of choice.

Question 56

An 8-year-old boy presents with a painless limp. Radiographs demonstrate fragmentation of the capital femoral epiphysis with lateral subluxation.

According to the Herring lateral pillar classification, greater than 50% of the lateral pillar height is maintained. What is the classification and recommended treatment?

Explanation

This describes a Herring B (lateral pillar >50% maintained) Legg-Calvé-Perthes disease. In children over 8 years old, containment surgery (e.g., femoral or pelvic osteotomy) yields significantly better outcomes than nonoperative treatment.

Question 57

In the Ponseti method for treating idiopathic clubfoot, what is the correct sequence of deformity correction?

Explanation

The mnemonic CAVE dictates the sequence of correction in the Ponseti method: Cavus (elevating the first ray), Adductus, Varus, and finally Equinus (often requiring a percutaneous Achilles tenotomy).

Question 58

A 13-year-old premenarchal female (Risser 0) presents with adolescent idiopathic scoliosis. Standing PA radiographs reveal a right thoracic curve of 35 degrees. What is the most appropriate management?

Explanation

In a skeletally immature patient (Risser 0-2) with a curve between 25 and 45 degrees, full-time bracing (TLSO) is indicated to halt progression. Observation is primarily reserved for curves less than 25 degrees.

Question 59

A newborn is diagnosed with fibular hemimelia. Which of the following associated anomalies is most consistently seen in this condition?

Explanation

Fibular hemimelia is frequently associated with anterolateral tibial bowing, absent lateral rays, ball-and-socket ankle, and knee anomalies including anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) deficiency.

Question 60

A 2-year-old child presents with a congenital spinal deformity. Radiographs show a fully segmented hemivertebra at T8.

Which of the following is the most appropriate next step in evaluation to rule out associated anomalies?

Explanation

Congenital scoliosis is highly associated with VACTERL anomalies. Cardiac (e.g., septal defects) and genitourinary anomalies (e.g., unilateral renal agenesis) must be evaluated using echocardiography and renal ultrasound.

Question 61

A 14-year-old gymnast presents with lower back pain radiating to the posterior thighs. Radiographs show a Grade 3 (75%) isthmic spondylolisthesis at L5-S1 with a high slip angle. What is the best surgical approach?

Explanation

For high-grade (>50%) isthmic spondylolisthesis with a high slip angle or signs of sagittal imbalance, reduction and circumferential (anterior/posterior) fusion or instrumented posterior fusion with interbody support is indicated.

Question 62

A 6-year-old boy with spastic quadriplegic cerebral palsy (GMFCS Level V) is evaluated for hip surveillance. AP pelvis radiograph reveals a migration percentage (Reimer's migration index) of 45% bilaterally. What is the most appropriate management?

Explanation

A migration percentage >40% in a child with spastic CP indicates significant subluxation requiring bony reconstruction. Soft tissue releases alone are insufficient; VDRO with or without pelvic osteotomy is the standard of care.

Question 63

A 14-year-old boy sustains an ankle injury. Radiographs reveal an intra-articular fracture of the anterolateral distal tibial epiphysis. This fracture pattern (Tillaux) occurs because of which of the following physeal closure sequences?

Explanation

The distal tibial physis closes from central to anteromedial to posteromedial, and finally anterolateral. The anterolateral portion remains open longest, making it susceptible to avulsion by the anterior inferior tibiofibular ligament.

Question 64

A 6-year-old falls from monkey bars and sustains a widely displaced Gartland type III extension-type supracondylar humerus fracture. The hand is pink, but the radial pulse is absent. What is the immediate next step in management?

Explanation

In a 'pink, pulseless' hand associated with a displaced supracondylar humerus fracture, the initial step is urgent closed reduction and percutaneous pinning. The pulse often returns after fracture reduction.

Question 65

A 4-year-old child presents with multiple long bone fractures after minimal trauma, blue sclerae, and dentinogenesis imperfecta.

Which of the following is the underlying genetic defect in the most common form of this condition?

Explanation

Osteogenesis Imperfecta (OI) is most commonly caused by autosomal dominant mutations in the COL1A1 or COL1A2 genes. This leads to quantitative or qualitative defects in Type I collagen.

Question 66

A 5-year-old child with achondroplasia presents with increased waddling gait and lower back pain. Which of the following spinal pathologies is most characteristic and concerning in patients with this skeletal dysplasia?

Explanation

Achondroplasia is characterized by a narrowed spinal canal and a high risk of foramen magnum stenosis (which can cause sudden death in infants) as well as symptomatic thoracolumbar kyphosis and lumbar spinal stenosis.

Question 67

A 3-year-old boy initially treated successfully with the Ponseti method for idiopathic clubfoot presents with dynamic supination of the foot during the swing phase of gait. Passive range of motion is normal. What is the treatment of choice?

Explanation

Dynamic supination in a previously corrected clubfoot is a classic sign of relapse. Since the foot is passively correctable, anterior tibial tendon (ATT) transfer to the lateral cuneiform is the standard procedure to balance the foot dynamically.

Question 68

During clinical gait analysis of a child with spastic diplegic cerebral palsy, a "crouch gait" is identified. Which combination of joint deformities best defines this gait pattern?

Explanation

Crouch gait in cerebral palsy is characterized by excessive hip and knee flexion combined with excessive ankle dorsiflexion (calcaneus) during the stance phase. It often results from over-lengthened Achilles tendons.

Question 69

A 13-year-old obese male presents with acute on chronic left groin pain. Radiographs reveal a severe unstable slipped capital femoral epiphysis (SCFE). He undergoes in situ pinning. What is the most significant risk associated with an unstable SCFE compared to a stable one?

Explanation

Unstable SCFE (defined as the inability to bear weight even with crutches) carries a much higher risk of AVN (up to 47%) compared to stable SCFE. Urgent decompression or careful positioning is debated, but AVN risk is definitively the most significant and devastating complication.

Question 70

A 4-year-old child presents with a limp, refusal to bear weight, and a temperature of 38.6°C. WBC is 13,000/mm3, and ESR is 45 mm/hr. According to the Kocher criteria, what is the probability that this child has septic arthritis of the hip?

Explanation

The child meets 3 of the 4 Kocher criteria (fever >38.5°C, non-weight bearing, WBC >12k, ESR >40). The probability of septic arthritis with 3 positive predictors is approximately 93%.

Question 71

An 8-week-old infant is being treated with a Pavlik harness for a dislocated left hip. During a follow-up visit, you notice the infant lacks active knee extension on the left side, though sensation appears intact. Which of the following is the most appropriate next step in management?

Explanation

The infant has developed a femoral nerve palsy, a known complication of extreme hyperflexion in a Pavlik harness. The harness must be discontinued or significantly relaxed immediately to allow for neurologic recovery, which usually occurs within days to weeks.

Question 72

A 2-week-old infant is undergoing Ponseti casting for idiopathic clubfoot. The deformity is being corrected sequentially. What is the final component of the clubfoot deformity to be corrected before application of the final cast?

Explanation

The Ponseti method corrects deformities in the specific order of CAVE (Cavus, Adductus, Varus, Equinus). Equinus is corrected last, frequently requiring a percutaneous Achilles tenotomy to achieve adequate dorsiflexion.

Question 73

A 3-year-old obese female presents with progressive bowing of her right leg. Radiographs reveal a metaphyseal-diaphyseal angle (Drennan angle) of 18 degrees.

What is the most appropriate initial management?

Explanation

A metaphyseal-diaphyseal angle >16 degrees in a 3-year-old with characteristic bowing strongly indicates infantile Blount's disease. Initial management for children under age 4 with Langenskiöld stage I-II disease is full-time bracing with a KAFO.

Question 74

A 6-year-old boy presents with a painless limp. Radiographs demonstrate sclerosis and fragmentation of the capital femoral epiphysis. Which of the following is the most important prognostic factor in Legg-Calvé-Perthes disease?

Explanation

Age at clinical onset is the single most important prognostic factor in Legg-Calvé-Perthes disease. Children who develop the disease before age 6 generally have a more favorable prognosis and greater potential for spherical remodeling.

Question 75

A 6-year-old falls on an outstretched hand and sustains a completely displaced, extension-type supracondylar humerus fracture. The hand is pink but the radial pulse is non-palpable. After closed reduction and percutaneous pinning, the hand remains pink and well-perfused, but the pulse is still absent. What is the most appropriate next step?

Explanation

In a "pink, pulseless" hand following reduction of a supracondylar fracture, collateral circulation is sufficient for perfusion. The standard of care is close observation and hospital admission, as the palpable pulse typically returns within 24 to 48 hours.

Question 76

A 5-year-old child sustains a minimally displaced (<2 mm) lateral condyle fracture of the humerus. It is treated conservatively. At the 4-month follow-up, the fracture shows established nonunion. What is the most common long-term complication of a nonunion of the lateral humeral condyle?

Explanation

Nonunion of a lateral condyle fracture often leads to a progressive cubitus valgus deformity as the medial side continues to grow. Over time, this valgus stretching causes a tardy ulnar nerve palsy.

Question 77

A 5-year-old child with spastic quadriplegic cerebral palsy is found to have a migration percentage of 45% in the right hip. The child is a GMFCS level V. What is the most appropriate management?

Explanation

A migration percentage >40% in a spastic CP patient (especially GMFCS V) indicates significant hip subluxation unresponsive to soft tissue release alone. Bony reconstructive surgery, typically a VDRO of the femur (often with a pelvic osteotomy), is required to prevent painful dislocation.

Question 78

A 13-year-old male presents with recurrent ankle sprains and a rigid flatfoot. Radiographs show a "C-sign" on the lateral view.

Which of the following physical exam findings is most characteristic of this condition?

Explanation

The "C-sign" on a lateral radiograph indicates a talocalcaneal coalition. The hallmark physical exam finding for a tarsal coalition is decreased or absent subtalar motion and a rigid, unyielding flatfoot deformity.

Question 79

A 4-year-old child with blue sclerae, dentinogenesis imperfecta, and multiple prior fractures is diagnosed with Osteogenesis Imperfecta (OI). Which genetic mutation is most commonly associated with this condition?

Explanation

Osteogenesis imperfecta is most commonly caused by an autosomal dominant mutation in the COL1A1 or COL1A2 genes. This defect leads to qualitative or quantitative abnormalities in type I collagen synthesis.

Question 80

A 10-month-old infant with achondroplasia presents for a routine evaluation. Which of the following orthopedic manifestations is an absolute indication for urgent surgical intervention in this patient population?

Explanation

Infants with achondroplasia are at high risk for foramen magnum stenosis, which can cause cervicomedullary compression, central apnea, and sudden death. Myelopathy or profound compression is an absolute indication for urgent suboccipital decompression.

Question 81

A 2-year-old child presents with anterolateral bowing of the left tibia and a newly diagnosed fracture through the apex of the curve. The condition is most closely associated with which of the following systemic disorders?

Explanation

Congenital pseudarthrosis of the tibia (CPT) typically presents with anterolateral bowing and is highly associated with Neurofibromatosis type 1 (NF1). Approximately 50% of patients with CPT have an underlying diagnosis of NF1.

Question 82

A 14-year-old girl with adolescent idiopathic scoliosis (AIS) has a right thoracic curve of 48 degrees. She is premenarchal and Risser stage 0. What is the most appropriate management?

Explanation

In a highly skeletally immature patient (Risser 0, premenarchal) with an AIS curve approaching or exceeding 45-50 degrees, the risk of progression is nearly 100%. Surgical intervention, typically posterior spinal fusion, is indicated to prevent severe deformity.

Question 83

A 5-year-old boy presents with a 2-day history of a right-sided limp and mild hip pain. He is afebrile with normal inflammatory markers. Ultrasound shows a small effusion in the right hip. He had an upper respiratory infection a week ago. What is the most appropriate management?

Explanation

The clinical picture of mild hip pain, normal inflammatory markers, afebrile status, and recent URI strongly suggests transient synovitis. This is a self-limiting condition best treated with NSAIDs, rest, and supportive care.

Orthopedic Prometric MCQs - Chapter 3 Part 1

Orthopedic Prometric MCQs - Chapter 3 Part 12

Orthopedic Prometric MCQs - Chapter 3 Part 12

Chapter Index