Question 1

A 4-year-old girl has unilateral idiopathic avascular necrosis involving the entire femoral head. Sixty percent of the height of the lateral column is resorbed. There is no lateral subluxation or physeal disturbance. The range of abduction is 30°. Recommended treatment consists of:

Explanation

The young age is the overwhelmingly positive factor in this patient. None of the findings mandate a more vigorous approach than observation. The Atlanta Scottish Rite orthosis has not been proven to have any effect on the disorder. Femoral osteotomy would only be possibly indicated, if there were subluxation greater than 25%. Iliac osteotomy would only be indicated in this age group, if there were subluxation and/or other poor prognostic factors. Petrie cast is indicated only if the patient has subluxation.

Question 2

A 13-year-old girl has hip pain and the inability to bear weight. On anteroposterior and lateral hip radiographs the femoral head is displaced inferiorly and posteriorly by 50% of its diameter. Recommended treatment includes:

Explanation

In situ fixation has results superior to any of the other methods. Besides being extremely cumbersome, spica cast treatment carries significant risk of redisplacement and chondrolysis. There is no indication for traction in this situation. The amount of displacement can be accepted as long as it is stabilized. Metaphyseal osteotomy carries a risk of avascular necrosis. It should only be undertaken in grade III slips.

Question 3

A newborn infant in the nursery must be seen because of his foot. The dorsum of the foot rests against the tibia. The heel moves up when the forefoot moves down. Power is present in all muscles. The foot has an arch and the leg lengths are equal. The diagnosis is:

Explanation

Calcaneovalgus foot has all of these findings and resolves spontaneously. Fibular hemimelia typically has less calcaneus attitude and more valgus and shortening. Vertical talus entails loss of an arch and loss of cohesive movement of the foot as a whole. There is no evidence of muscle weakness. There is no evidence of a neuropathic component.

Question 4

A newborn girl is noted to have decreased movement in the right upper extremity. She was large (10 lbs) at birth and was delivered vaginally with shoulder dystocia. She does not have elbow flexion, external shoulder rotation, or abduction. She has had weak finger flexion for 3 months. At 4-months-old, she regains the ability to flex her elbow. Recommended treatment includes:

Explanation

Conservative therapy is predicted to bring a good result because biceps are returning at four months of age. However, stretching of the shoulder is indicated to maintain a range of external rotation and abduction. Magnetic resonance imaging is only indicated if there is a need to consider microvascular repair. Tendon transfers are performed later (at several years of age), if shoulder abduction and external rotation are significantly limited. Microvascular repair is mainly considered in patients who do not have return of biceps function by five months. Open reduction is indicated later (if the shoulder joint is subluxated or severely contracted) after motor recovery has reached a plateau.

Question 5

A 7-year-old boy with diplegic cerebral palsy has had lengthening of his hamstrings and heelcords. He is examined 2 years later. He walks with the knees nearly straight throughout the gait cycle and circumducts each extremity during swing. This pattern is most likely due to:

Explanation

The straight legs and circumduction suggest spasticity of the rectus femoris as the most likely cause. Recurrent hamstring tightness (by itself) would cause the opposite combination of problems. Overlengthening of the heelcords usually causes increased dorsiflexion at the ankles and would help to increase the flexion moment rather than the extension. Contracture of the tensor fascia lata is extremely rare in cerebral palsy. Spasticity in the psoas muscle would not lead to a stiff knee gait.

Question 6

A 3-year-old girl is brought in for evaluation of leg alignment. She has bilateral foot progression angles of 35° internal. Her thigh-foot angles are 40° internal. Her hip rotation in the prone position is 50° external and 30° internal. The metaphysealdiaphyseal angle is 2° on each side. Recommended treatment includes:

Explanation

The tibial torsion described has an excellent chance of resolution over time. Observation is indicated. This child has tibial torsion. The Denis Browne bar has not been proven to affect the natural history of tibial torsion. The knee-ankle-foot orthoses are used for genu varum, which is not the primary problem in this case. A femoral osteotomy is rarely used to correct femoral anteversion in older children. A tibial osteotomy is rarely used to correct tibial torsion in older children.

Question 7

A newborn baby has a foot that is dorsiflexed and in valgus. The differential diagnosis includes all of the following conditions except:

Explanation

The foot in a patient with tibial hemimelia does not resemble the other four conditions described; the foot is in equinus and varus. Calcaneovalgus foot is dorsiflexed and everted through the axis of the ankle joint. A vertical talus has excessive forefoot dorsiflexion and valgus. A patient with an L5 myelomeningocele may have this appearance due to activity of the dorsiflexors and evertors, with absent power in the plantarflexors and invertors. Due to the posteromedial bow in the tibia, the foot may appear dorsiflexed and in valgus.

Question 8

A 6-year-old girl with osteogenesis imperfecta has severe bowing of both femurs. The family is interested in surgery to correct the condition. This method will give her the longest interval between procedures in the future:

Explanation

Telescoping or Bailey-Dubow rods are able to grow with the patient and maintain stabilization for a mean of 4 years between operations in growing children. Without the addition of internal fixation, bowing is likely to resume. Although a single rod is likely to provide current stability, bowing is likely to occur as the patient grows and the bone becomes longer than the rod. Parallel rods do not interlock and are likely to splay and lose fixation. There are no reports of large segment allograft replacement for diaphyses in osteogenesis imperfecta. In the absence of internal fixation, bowing is likely to resume as growth occurs.

Question 9

An infant is seen in the office for the first time. She has slender, stiff fingers with few creases, elbow range of motion 20° to 45°, and internally rotated arms. Her legs are flexed and externally rotated at the hip. Knee range of motion is 15° to 40° of flexion, and she has bilateral clubfeet that are stiff. The most likely diagnosis is:

Explanation

The patient has enough joint contractures to make arthrogryposis a likely diagnosis. Larsen syndrome is characterized by dislocation of multiple joints. Cerebral palsy is characterized by spasticity and flexors overpowering extensors. Ehlers-Danlos is characterized by hyperlaxity of the large joints. Down syndrome does not present with stiffness.

Question 10

Which of the following statements best characterizes the natural history of metatarsus adductus in a newborn:

Explanation

Virtually all patients with metatarsus adductus will improve with time in the absence of active treatment. Casts are not needed for the majority of cases because spontaneous improvement is by far the most common outcome. Reverse last shoes are not needed in the majority of patients with metatarsus adductus. Most patients will not need surgery. Equinus of the hindfoot is not part of the pathology in metatarsus adductus.

Question 11

A 2½-year-old boy has severe spastic diplegia and hips that are subluxating. His abduction is 20° on each side. The migration index is 35% on each side. Recommended treatment includes:

Explanation

If followed by postoperative bracing, lengthening of the adductors is usually successful in children younger than 4 to 6 years of age. Traction would not be appropriate because the muscles are spastic. The surgical plan does not include the most important component weakening the overactive adductors. Trochanteric transfer is not advisable in patients younger than 8 years old. Trochanteric transfer would not help decrease the overpull of the adductors which is the cause of the subluxation. Nighttime abduction splinting should be a component of the care after surgery. Bracing alone would not be an adequate treatment. Physical therapy in the absence of surgery does not seem to be enough to overcome the pull of the adductors.

Question 12

A 15-year-old boy has a Salter type-2 fracture of the distal tibia. His foot is in valgus and external rotation. Recommended treatment is:

Explanation

There is a good chance that a satisfactory closed reduction may be achieved by correcting the valgus and external rotation. The fracture should first be reduced. There is a good chance of a satisfactory reduction. The patient is old enough that a significant physeal growth disorder is not likely. Magnetic resonance imaging is not indicated unless there is a question of physeal disorder after healing or an entrapped fragment.

Question 13

Adolescent girls with multiple radiographs for idiopathic scoliosis are statistically at increased risk for which of the following problems later in life:

Explanation

In a historical cohort study, the risk was increased to 1.7 times the expected rate of breast cancer. The radiation dose is currently lower. The exposure to the breast may be lowered by taking posteroanterior rather than anteroposterior films, and eliminating lateral films in routine situations.

Question 14

The mean amount of growth height occurring in each vertbra per year during later childhood and early adolescence is:

Explanation

The mean growth is 0.7 mm per vertebra per year. This measurement is averaged across all of the thoracic and lumbar vertebrae.

Question 15

Which of the following features is true of congenital scoliosis but not infantile idiopathic scoliosis:

Explanation

In congenital scoliosis, the vertebrae are abnormally formed from birth. The vertebrae are normal at birth in infantile idiopathic scoliosis. Age of onset is before age 3 in both types of scoliosis. The thoracic curve may be convex to the left slide or the right side in either curve type. In infantile idiopathic scoliosis, it is most commonly convex to the left. The rib-vertebral angle difference (angle between the apical vertebral endplate and the rib on the convexity minus the rib on the concavity) greater than 20° predicts an increased risk of worsening in infantile idiopathic scoliosis but not in congenital scoliosis. Bracing has not been shown to affect infantile idiopathic scoliosis.

Question 16

A 12-year-old child with sickle cell anemia has had pain in the distal femur for 1 day, a temperature of 101.5Â° F, and a white blood count of 14,000/mm3 . Plain films are unremarkable. Recommended treatment includes:

Explanation

Because the odds are greatly in favor of a noninfectious process, it is appropriate to treat empirically with rehydration and analgesia. Magnetic resonance imaging would not distinguish between infection and vaso-occlusive crisis. Bone scan would not distinguish between infection and vaso-occlusive crisis. Needle biopsy is not necessary at this stage since the odds are high (greater than 95%) that the process is not infection. White blood cell scan is not able to distinguish between infection and vaso- occlusive crisis.

Question 17

A 6-year-old girl is wearing a seatbelt but no shoulder harness when the car she is occupying strikes another car. She suffers an abdominal contusion as well as a spine injury. The facets of L1 and L2 are spread apart as is the disk between them. The angle between the two vertebrae is 35°. The neurologic exam is within normal limits. Recommended treatment includes:

Explanation

Open reduction and 2-level fusion is the simplest way of handling this injury. Immobilization in a hyperextension cast is likely to exacerbate the abdominal injury. An orthosis is not likely to reduce the deformity. Traction would not be a good mechanism to reduce the deformity. In situ fusion would be insufficient without instrumentation.

Question 18

Secondary ossification of the elbow

Explanation

Secondary ossification is very imprtant in managing fractures. It begins at age 1-2 and is complete by 14 years girls and 16 years in boys.

Question 19

Definitive diagnosis of septic arthritis is made by:

Explanation

Definitive diagnoisis of septic arthritis is made by needle asperation.

Question 20

Osteomyelitis in the child

Explanation

Osteomyelitis in the child requires 3-6 weeks of antiobiotics which may be administered parenterally or internally.

Question 21

All of the following characterize lateral patellar compression syndrome except:

Explanation

By definition, patients with a lateral patellar compression syndrome do not have a subluxation or dislocation of the patella.

Question 22

Osteochondral defects occur bilaterally in the distal femur in approximately:

Explanation

Osteochondral defects occur bilaterally in the distal femur for approximately 20% to 30% of patients. The fact that 20% to 30% of patients with an osteochondral lesion in the distal femur have bilateral involvement suggests that there is a predisposition to the development of a lesion at this location, either genetic or secondary to repetitive microtrauma.

Question 23

The magnetic resonance imaging signs that suggest instability of an osteochondral dissecans lesion include all the following except:

Explanation

The presence of a high signal intensity line at the interface between the lesion and the underlying bone suggests instability of an osteochondritis dissecans lesion.

Question 24

The neonatal hand:

Explanation

The neonatal hand is proportionally different from the mature hand.

Question 25

Pediatric bone:

Explanation

Pediatric bone has less mineral and more vascular channels than adult bone. This gives it a lower bending strength and lower modules of elasticity than adult bone.

Question 26

In congenital lesions characterized by failure of formation of parts, the most functional, without treatment, is/are:

Explanation

C entral deficiencies allow a wide grasp, good release and pinch. These are also termed "cleft hand". The other conditions produce greater impairment.

Question 27

Which category of failure of formation anomalies is most often associated with systemic anomalies?

Explanation

Radial deficiencies are often seen in the later association. which may include cardiac,renal,anorectal and tracheoesphogeal abnormalities.

Question 28

Arthrogryposis multiplex congenita:

Explanation

Arthrogryposis multiplex congenita is an idiopathic disorder that may be due to a primary deficiency of anterior horn cells. Arthrogryposis multiplex congenita results in lack of muscle development; the joint stiffness is secondary to this. It is usually reasonably symmetrical.

Question 29

What percentage of the human genome represents the actual genes:

Explanation

The percentage of the genome that represents the sequence of our genes is approximately 5%. The rest of the genome codes are for initiator and termination sequences, maintenance functions, and unknown functions.

Question 30

In studying a newly recognized disorder using a large population of affected individuals, geneticists discover that although the disorder often affects siblings, it was rarely, if ever, detected in their ancestors. This disorder most closely follows which pattern of inheritance:

Explanation

Autosomal recessive conditions classically show â horizontalâ inheritance. Ancestors do not display the gene because they would likely have only one copy of the mutant allele. Only when two carriers reproduce is the phenotype manifest in approximately onefourth of their offspring. Autosomal dominant inheritance is characterized by vertical transmission. Many generations manifest the trait because it takes only a single copy of a mutant allele to display the phenotype. Sex-linked conditions are often traced back in a family. Normally the males are affected and the females are carriers. Multifactorial conditions are thought to result from the combination of different genes. Although the risk of recurrence in kindred is somewhat greater than the population as a whole, it is still quite low (only a few percent). It is rare for siblings to be affected. Anticipation refers to the phenomenon in which successive generations are likely to display more severe forms of a given disorder. Myotonic dystrophy is a classic example of this phenomenon.

Question 31

Diseas es caused by enzyme deficiency are commonly inherited by which of the following patterns:

Explanation

Two copies of a mutant allele are required to reduce enzyme function to levels that cause clinical impairment. Enzyme defects are rarely inherited by an autosomal dominant pattern because even half of the normal activity of most enzymes is adequate to maintain normal function. Enzyme defects are rarely inherited in an X-linked dominant pattern because one copy of a mutant allele is usually sufficient. Multifactorial inheritance refers to the interaction of multiple, or different genes, to produce a disorder. Enzyme deficiencies are typically the result of a defect in a single gene. Because enzymes are typically coded by a single gene, they follow mendelian patterns.

Question 32

Morquio syndrome is caused by a deficiency in:

Explanation

Morquio syndrome is a member of the family of mucopolysaccharidoses. Morquio syndrome is a deficiency in the enzyme galactose-6-sulfatase. A deficiency in galactose-6-sulfatase results in increased urinary excretion of keratosulfate. Alpha-L-iduronidase is deficient in Hurler syndrome. Beta-glucuronidase is deficient in some rare mucopolysaccharidoses. Fibroblast growth factor receptor protein is deficient in achondroplasia. Sulfate transport protein is deficient in diastrophic dysplasia.

Question 33

Polymerase chain reaction (PC R) is best characterized by which of the following descriptions:

Explanation

Polymerase chain reaction refers to denaturing DNA, isolating a segment of interest with known primers, and reannealing the strands multiple times to produce exponential copies of a segment.

Question 34

Pleiotropy is demonstrated by which of the following examples:

Explanation

The term pleiotropy refers to a disease taking different shapes in various patients. Variation in the severity of a given problem is better termed "variable expressivity." Target joints are not genetically determined. Hurler syndrome usually not being present in prior generations of an affected patient is an example of autosomal recessive inheritance. The term pleiotropy refers to a disease taking different shapes in different subjects, whereas the cause of patients with Ollier disease having more involvement on one side of the body is unknown.

Question 35

Which of the following is the most common concern regarding anesthesia for a patient with juvenile rheumatoid arthritis:

Explanation

Stiffness and mandibular hypoplasia are fairly common in juvenile rheumatoid arthritis (JRA) due to inflammation of the temporomandibular joint that affects the growth plates of the mandibles. Basilar invagination is rare in JRA. Rotatory subluxation of C1-C2 is rare in JRA. Subaxial subluxation is rare in JRA. Cervical stenosis is not a clinical problem in JRA.

Question 36

A 4-year-old boy is brought to a clinic because he has been fussy, febrile, and unable to bend over for the past 4 days. In the office, his temperature is 38.2° C and his neurologic examination is normal. His lumbar lordosis is flattened and he resists flexion or extension. He has normal range of hip motion. Plain films of the lumbar spine are normal. The next imaging study should be:

Explanation

Magnetic resonance imaging should be the next step to rule out pyogenic spondylitis. Ultrasound has not been proven effective in evaluation of anterior spinal pathology. Computed tomograms do not have a greater sensitivity than plain films in early diagnosis of infection. An indium labeled scan may yield diagnostic information but would not be the preferred test because of the time needed and inability to provide other diagnostic information. Hip arthrogram would not be the next step because the hip range of motion is normal. Even if hip pathology were suspected, the next step would be a plain film and an ultrasound.

Question 37

A 6-year-old child suffers a displaced fracture of the distal humerus in the supracondylar region. Neurologic and vascular exams are normal. The surgeon decides to reduce and pin the fracture. Which of the following risks increases if the procedure is delayed more than 8 hours?

Explanation

A retrospective comparison study has shown no increase of risks in delayed treatment of supracondylar fractures.

Question 38

Which of the following statements is true regarding the growth plates around the ankle:

Explanation

The distal tibia grows more than the distal fibula. The anterolateral portion of the tibial physis ceases growing last, thus explaining the phenomenon of the Tillaux fracture. The physis of the distal fibula is always located more distally than the distal tibia. The two physes are not conjoined.

Question 39

Which of the following is the most common final attribution of back pain in children and adolescents after all appropriate diagnostic studies are performed:

Explanation

The majority of children and adolescents do not have an identifiable cause of back pain after all appropriate tests are performed. Of the smaller percent of patients with an actual diagnosis, spondylolysis followed by herniated nucleus pulposus are most common.

Question 40

Which of the following is the most definitive means of making a diagnosis of active skeletal tuberculosis:

Explanation

The lower thoracic-upper lumbar spine is most commonly affected by tuberculosis. The most definitive diagnosis is by culture and histologic examination.

Question 41

Which of the following descriptions is more characteristic of tuberculosis than of pyogenic spondylitis:

Explanation

Vertebral destruction exceeds disc destruction in tuberculosis. Bony changes occur earlier in tuberculosis than in pyogenic spondylitis. Involvement of multiple contiguous levels is more common in tuberculosis than pyogenic spondylitis. Bony erosions seen on computerized tomography are large in tuberclosis and small in pyogenic spondylitis. Magnetic resonance imaging often shows significant soft tissue involvement in both disorders.

Question 42

A 5-year-old girl comes into the clinic with back pain. Her family has just moved to the United States from southeastern Asia. A lateral radiograph shows destruction of T11, T12, and L1. Magnetic resonance imaging shows a moderate posterior soft tissue mass. A neurological exam is normal. Biopsy confirms tuberculosis. For treatment of the girlâ s spinal problem, recommended treatment includes:

Explanation

Anterior debridement, strut graft, and posterior fusion with instrumentation provide the patient with the best chance of a positive result. This procedure minimizes graft dislodgement and posterior overgrowth. A two-drug therapy for at least 6 months leaves the patient at a significant risk of progressive kyphosis and neurologic deficit. A two-drug therapy for at least 6 months along with a body cast also leaves the patient with significant risk of progressive kyphosis and neurologic deficit. The lack of anterior support from a two-drug therapy and posterior spinal fusion to prevent deformity leaves the patient with significant risk of kyphosis. Even with an anterior spinal debridement and a rib strut graft, there is a risk of graft dislodgment over this large defect and of posterior growth into kyphosis.

Question 43

A dorsal approach has which of the following characteristics with regard to a posteromedial approach in the surgical treatment of congenital vertical talus:

Explanation

The dorsal approach has not shown evidence of avascular necrosis, whereas the posteromedial approach has shown such changes at follow-up in as many as 40% of cases. The dorsal approach requires a less extensive dissection than the posteromedial approach. The dorsal approach does not require or permit plication of the talonavicular capsule, whereas the posteromedial approach does. The dorsal approach does not appear to have a higher rate of redislocation of the talonavicular joint than the posteromedial approach. The dorsal approach requires a shorter tourniquet time than the posteromedial approach.

Question 44

Which of the following conditions is not associated with an increased risk of congenital vertical talus?

Explanation

Patients with cerebral palsy do not have an increased risk of congenital vertical talus, but they may develop an acquired neuromuscular vertical talus. Patients with myelomeningocele have approximately a 5% to 10% risk of vertical talus, far above that of the general population. Arthrogryposis is associated with an increased risk of vertical talus. Nail patella syndrome is associated with an increased risk of vertical talus. Sacral agenesis is associated with an increased risk of vertical talus.

Question 45

Scoliosis in Marfan syndrome, as compared to idiopathic scoliosis, is characterized by which of the following:

Explanation

Scoliosis curves are much more likely to begin in the juvenile period than idiopathic scoliosis. There is no significant difference in the likelihood of left thoracic curves in Marfan syndrome. Brace treatment is less likely to be successful in Marfan syndrome than in idiopathic scoliosis. Marfan patients with scoliosis are more likely to have back pain. Marfan curves are more likely to progress in adulthood.

Question 46

Which of the following statements is true of demineralized bone matrix:

Explanation

Demineralized bone matrix is weakly osteoinductive. The term osteogenic refers to direct transmittal of cells capable of making bone. Demineralized bone matrix is not osteogenic. Demineralized bone matrix varies in efficacy between different forms and different methods of sterilization. The term osteoconduction refers to provision of a favorable scaffold and environment for bone formation. Demineralized bone matrix is osteoconductive.

Question 47

A 16-year-old boy with type I Ehlers-Danlos syndrome has a spinal curvature that has progressed 18Â° in the past year. The curve is a double major type with a C obb angle of 60° in each curve. There is no associated kyphosis. The following treatment is recommend:

Explanation

Posterior fusion and instrumentation is the best-documented treatment. Although this form of treatment is followed by an increased incidence of wound healing problems, the problems can be treated. Observation is not recommended because the curve is highly likely to increase and cause a decrease in pulmonary function. Bracing has no role in large curves, and it is not known if bracing is successful at all in Ehlers-Danlos syndrome. Anterior fusion with instrumentation would be difficult with a double curve. Anterior fusion carries an increased risk due to vascular fragility. It is not necessary because there is no increased risk of crankshaft or pseudarthrosis. There is no particular reason for adding an anterior procedure in this situation in view of the vascular risk.

Question 48

Scoliosis in osteogenesis imperfecta is characterized by which of the following:

Explanation

Scoliosis in osteogenesis imperfecta (OI) is due primarily to ligamentous laxity. Scoliosis in OI is due primarily to ligamentous laxity, not bony fractures. There is no association between brainstem impression and scoliosis. Scoliosis in OI rarely responds to brace treatment. Scoliosis, when present in OI, is a major impairment of quality of life.

Question 49

Which of the following is not a specific feature in making the diagnosis of a dystrophic curve in neurofibromatosis 1:

Explanation

Vertebral rotation is not a specific characteristic of dystrophic curves. Rotation is more pronounced in dystrophic curves than in nondystrophic curves, but it is commonly present in both types of curves. Penciling of the ribs is one of the features specific for dystrophic curves in neurofibromatosis 1. Scalloping of the vertebrae anteriorly and posteriorly is characteristic of dystrophic curves in neurofibromatosis 1. Widening of the neural foramen is specific for dystrophic curves in neurofibromatosis 1. Widening of the neural foramen is due to tumorous masses passing through the foramen. Thinning of the transverse process is a characteristic of dystrophic curves in neurofibromatosis 1.

Question 50

The spine in familial dysautonomia is characterized by which of the following:

Explanation

There is an increased risk of loss of fixation in familial dysautonomia curves due to decreased bone density and curve rigidity. Scoliosis is common in patients with familial dysautonomia and affects up to one-half of patients with the disorder. The curves in familial dysautonomia are rigid, leading to limited correction. The bone density in familial dysautonomia is decreased. Spinal stenosis is not reported in patients with familial dysautonomia.

Question 51

A 14-year-old obese boy presents with acute-on-chronic slipped capital femoral epiphysis (SCFE). He undergoes in situ pinning. What is the most significant risk factor for developing chondrolysis in this patient?

Explanation

Unrecognized hardware penetration into the joint is the most consistently identified risk factor for chondrolysis following the surgical treatment of SCFE. Accurate intraoperative fluoroscopy is critical to confirm the pin is completely within the femoral head.

Question 52

A 35-year-old man sustains a displaced midshaft clavicle fracture. Which of the following is considered an absolute indication for operative fixation?

Explanation

Absolute indications for operative fixation of clavicle fractures include open fractures, vascular compromise, and progressive neurologic deficits. Severe shortening and floating shoulder are generally considered relative indications depending on patient factors.

Question 53

A 65-year-old woman with advanced rheumatoid arthritis presents with neck pain and mild myelopathy. Flexion-extension radiographs demonstrate 9 mm of atlantoaxial subluxation. What primary anatomic structure is compromised, leading to this instability?

Explanation

The transverse ligament is the primary restraint to anterior translation of the atlas on the axis. Its attenuation or rupture due to inflammatory pannus in rheumatoid arthritis leads to atlantoaxial subluxation.

Question 54

During a total knee arthroplasty, the surgeon notes the knee is tight in flexion and well-balanced in extension. Which of the following adjustments is most appropriate to balance the knee?

Explanation

A knee that is tight in flexion but balanced in extension requires an isolated increase in the flexion gap. Downsizing the femoral component (using anterior referencing) decreases the posterior condylar offset, thereby opening the flexion gap without affecting the extension gap.

Question 55

A 24-year-old athlete sustains a severe knee twisting injury. An MRI reveals an ACL tear and a concomitant "double PCL" sign. What additional injury does this sign indicate?

Explanation

The "double PCL" sign on a sagittal MRI is a classic indicator of a bucket-handle tear of the medial meniscus that has displaced into the intercondylar notch, lying parallel and anterior to the intact PCL.

Question 56

A 55-year-old poorly controlled diabetic man presents with a swollen, erythematous, but painless foot. Radiographs show dissolution of the tarsometatarsal joints with early fragmentation and debris. What is the most critical initial management?

Explanation

The patient has acute Charcot arthropathy (Eichenholtz stage I). The most critical initial non-operative management is strict immobilization and offloading, typically achieved with a total contact cast, to halt progressive bone destruction and deformity.

Question 57

In bone graft biology, which of the following materials is unique in possessing osteogenic, osteoinductive, and osteoconductive properties simultaneously?

Explanation

Iliac crest bone graft (autograft) is considered the gold standard as it provides all three essential properties for bone healing: osteogenic (live cells), osteoinductive (growth factors), and osteoconductive (a structural scaffold).

Question 58

A 12-year-old boy presents with knee pain. Radiographs show a sunburst periosteal reaction and a Codman triangle in the distal femur. Biopsy reveals malignant spindle cells producing osteoid. What is the most appropriate initial step in treatment?

Explanation

The diagnosis is classic high-grade osteosarcoma. The standard of care consists of neoadjuvant chemotherapy to treat micrometastases and shrink the primary tumor, followed by wide surgical resection and adjuvant chemotherapy.

Question 59

A 28-year-old man sustains a complete laceration of the flexor digitorum profundus (FDP) in zone II. Following a robust multi-strand surgical repair, which rehabilitation protocol is most appropriate to minimize tendon adhesions?

Explanation

Early active extension and passive flexion (e.g., the modified Kleinert or Duran protocol) is the gold standard after zone II flexor tendon repairs. It stimulates intrinsic healing and excursion to prevent adhesions while preventing excessive tension that could rupture the repair.

Question 60

A 6-month-old infant is diagnosed with DDH that failed Pavlik harness treatment. A closed reduction and spica casting are planned. Under fluoroscopy, the "safe zone" of Ramsey is evaluated. What does this zone represent?

Explanation

The "safe zone" of Ramsey is the arc of hip abduction between the angle of maximal abduction (limited by adductor tightness) and the lower angle at which the hip redislocates or subluxates as it is adducted. If the safe zone is too narrow, an adductor tenotomy may be required.

Question 61

A 30-year-old man suffers a displaced talar neck fracture (Hawkins Type III). Which of the following blood vessels provides the primary vascular supply to the talar body, placing it at high risk for avascular necrosis in this injury?

Explanation

The artery of the tarsal canal (a major branch of the posterior tibial artery) provides the dominant blood supply to the talar body. Disruption of this network in displaced talar neck fractures (especially Hawkins Types II-IV) leads to a high rate of avascular necrosis.

Question 62

A 45-year-old laborer complains of numbness in his ring and small fingers and hand weakness. He demonstrates a positive Froment sign when asked to pinch a piece of paper. Which nerve is compressed, and which muscle is compensating?

Explanation

A positive Froment sign indicates ulnar nerve palsy, leading to weakness of the adductor pollicis. The patient compensates by hyperflexing the thumb interphalangeal joint, a motion powered by the median nerve-innervated flexor pollicis longus (FPL).

Question 63

A 16-year-old gymnast presents with severe mechanical back pain. Radiographs show a grade II isthmic spondylolisthesis at L5-S1. Non-operative management has failed after 6 months. What is the most appropriate surgical treatment?

Explanation

For a symptomatic grade II isthmic spondylolisthesis failing conservative care, an L5-S1 posterolateral fusion with pedicle screw instrumentation is the standard procedure. Direct pars repair is generally reserved for younger patients with pars defects but no significant slip (Grade 0 or very mild Grade I).

Question 64

A 32-year-old man falls on an outstretched hand and presents with dorsal wrist pain. Radiographs demonstrate a widened scapholunate interval of 5 mm on the AP view. What is the classic eponymous name for this radiographic sign?

Explanation

The Terry Thomas sign refers to an abnormally widened scapholunate interval (>3 mm) seen on AP radiographs, indicative of scapholunate ligament dissociation. The "spilled teacup" and "piece of pie" refer to lunate/perilunate dislocations.

Question 65

During an anterior cervical discectomy and fusion (ACDF) at C5-C6 using a left-sided approach, a retractor is placed medially to protect the visceral structures. Which nerve is most at risk of neuropraxia due to prolonged retractor compression?

Explanation

The recurrent laryngeal nerve courses in the tracheoesophageal groove and is highly vulnerable to stretch or compression from prolonged medial retractor placement during an anterior cervical approach, which can result in postoperative hoarseness.

Question 66

A 50-year-old woman has chronic lateral elbow pain exacerbated by resisted wrist extension and forearm supination. She has failed a year of conservative treatment, and surgery is planned. Which structure is the primary site of pathology being targeted?

Explanation

Lateral epicondylitis (tennis elbow) is primarily characterized by angiofibroblastic tendinosis of the origin of the extensor carpi radialis brevis (ECRB) tendon. Surgical intervention focuses on debridement or release of the ECRB.

Question 67

A 7-year-old boy presents with a painless limp. Hip radiographs reveal a fragmented, flattened capital femoral epiphysis consistent with Legg-Calvé-Perthes disease. Which of the following is considered one of Catterall's "head-at-risk" signs?

Explanation

In Legg-Calvé-Perthes disease, Catterall's "head-at-risk" signs portend a poorer prognosis. They include Gage sign (a V-shaped radiolucency in the lateral epiphysis and adjacent metaphysis), lateral (not medial) subluxation, calcification lateral to the epiphysis, and a horizontal physis.

Question 68

A 7-month-old girl presents with a persistently dislocated left hip after 6 weeks of compliant Pavlik harness treatment. What is the most appropriate next step in management?

Explanation

In an infant older than 6 months or after failed Pavlik harness treatment, the next appropriate step is an examination under anesthesia and an attempted closed reduction with spica casting. Continued use of the Pavlik harness after failure increases the risk of "Pavlik harness disease" and structural damage.

Question 69

A 6-year-old boy falls from monkey bars and sustains a displaced extension-type supracondylar humerus fracture. Examination reveals an inability to actively flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Which nerve is injured?

Explanation

The anterior interosseous nerve (AIN), a branch of the median nerve, is the most commonly injured nerve in pediatric extension-type supracondylar humerus fractures. It innervates the flexor pollicis longus and the flexor digitorum profundus to the index finger.

Question 70

A 72-year-old woman undergoes revision total hip arthroplasty. Intraoperatively, there is complete separation of the superior and inferior hemipelvis through the acetabulum, confirming pelvic discontinuity. Which of the following is the most appropriate acetabular reconstruction option?

Explanation

Pelvic discontinuity requires rigid fixation bridging the superior and inferior halves of the pelvis. A cup-cage construct, custom triflange, or pelvic distraction with a highly porous jumbo cup are the accepted treatments of choice to provide structural stability.

Question 71

A 45-year-old male sustains an acute twisting injury to his knee. MRI demonstrates a complete anterior cruciate ligament (ACL) tear and a medial meniscus posterior root tear with 3 mm of meniscal extrusion. What is the recommended surgical treatment?

Explanation

Medial meniscus posterior root tears result in a loss of hoop stresses, functioning biomechanically like a total meniscectomy. Transtibial pull-out repair at the time of ACL reconstruction restores joint kinematics and delays the onset of osteoarthritis.

Question 72

A 25-year-old male sustains a vertically oriented (Pauwels type III) displaced femoral neck fracture in a motor vehicle accident. What is the biomechanical advantage of using a sliding hip screw with a derotation screw compared to three parallel cancellous screws?

Explanation

Pauwels type III fractures are highly unstable due to significant vertical shear forces along the fracture line. A fixed-angle device such as a sliding hip screw provides superior biomechanical resistance to varus collapse compared to multiple cancellous screws in these vertical fracture patterns.

Question 73

A 22-year-old rugby player grabs an opponent's jersey and feels a pop in his ring finger. He cannot actively flex the distal interphalangeal (DIP) joint. Ultrasound shows the flexor digitorum profundus (FDP) tendon retracted into the palm. What is the classification and ideal timing for surgery?

Explanation

This is a Leddy and Packer Type I FDP avulsion, characterized by tendon retraction into the palm and complete disruption of the vincula. Surgery must be performed within 7 to 10 days to prevent permanent tendon retraction and ischemic necrosis.

Question 74

A 14-year-old boy presents with a permeative lytic lesion in the femoral diaphysis, an associated soft tissue mass, and an "onion-skin" periosteal reaction. Biopsy reveals uniform small, round blue cells. Which chromosomal translocation is most characteristic of this diagnosis?

Explanation

The clinical and radiographic presentation describes Ewing sarcoma. The t(11;22)(q24;q12) translocation is found in approximately 85% of these cases, resulting in the characteristic EWS-FLI1 fusion protein.

Question 75

During a primary total knee arthroplasty for a severe fixed varus deformity, sequential medial soft tissue release is required to balance the knee. After the removal of all medial osteophytes, which structure is classically released first?

Explanation

In a classic stepwise medial release for a fixed varus knee, medial osteophytes are excised first because they often tent the MCL. If the knee remains tight, the first soft tissue structure released is the deep medial collateral ligament, specifically its meniscotibial attachment.

Question 76

A 35-year-old male is admitted with a highly comminuted tibial shaft fracture and severe closed head trauma. He is obtunded, with a blood pressure of 110/70 mmHg. Intracompartmental pressure monitoring is performed. Which of the following values is most definitively diagnostic of acute compartment syndrome requiring urgent fasciotomy?

Explanation

Acute compartment syndrome is definitively diagnosed when the delta pressure (diastolic blood pressure minus absolute compartment pressure) falls below 30 mmHg. A delta pressure of 20 mmHg indicates severely impaired local tissue perfusion necessitating an immediate four-compartment fasciotomy.

Question 77

When analyzing the biomechanical properties of a tendon, it is noted that applying a constant load over a prolonged period causes the tendon to gradually elongate. This viscoelastic phenomenon is best described as:

Explanation

Creep is the time-dependent deformation or elongation of a viscoelastic material when it is subjected to a constant load. In contrast, stress relaxation is the decrease in internal stress over time when the material is held at a constant length or strain.

Question 78

A 21-year-old collegiate linebacker has a history of recurrent anterior shoulder dislocations. A 3D CT scan reveals 28% anterior glenoid bone loss and an engaging Hill-Sachs lesion. What is the most appropriate definitive surgical intervention?

Explanation

In a high-demand contact athlete with critical anterior glenoid bone loss (typically greater than 20-25%), isolated soft-tissue stabilization has an unacceptably high failure rate. A bony augmentation procedure such as the Latarjet coracoid transfer is the standard of care.

Question 79

A 30-year-old woman presents with a lytic epiphyseal lesion of the distal femur. Biopsy confirms a Giant Cell Tumor (GCT) of bone. Prior to surgical curettage, she is given neoadjuvant denosumab to consolidate the tumor margins. What is the mechanism of action of this medication?

Explanation

Denosumab is a human monoclonal antibody that binds directly to RANK ligand (RANKL). This prevents the activation of the RANK receptor on osteoclast precursors, which dramatically reduces the characteristic osteoclast-like giant cells in GCTs.

Question 80

A 65-year-old male complains of bilateral hand clumsiness, difficulty buttoning his shirt, and a wide-based gait. Examination shows hyperreflexia in the lower extremities and a positive Hoffmann's sign. He can ambulate but requires the use of a single cane. What is his Nurick classification grade?

Explanation

The Nurick classification evaluates the ambulatory status of patients with cervical spondylotic myelopathy. Grade 3 corresponds to difficulty walking that requires assistance or a cane, while the patient is not yet wheelchair-bound or bedridden.

Question 81

A 55-year-old patient with poorly controlled diabetes presents with a swollen, erythematous, and warm right foot. There are no open ulcers, and systemic vital signs are normal. Radiographs show soft tissue swelling but no fractures or dislocations. What is the initial treatment of choice?

Explanation

This clinical presentation is characteristic of an acute stage 0 or early stage I Charcot neuroarthropathy. The gold standard for initial management is immediate immobilization with a total contact cast and strict non-weight bearing to prevent progressive bone destruction and midfoot collapse.

Question 82

A 28-year-old man presents with a 6-month-old scaphoid waist fracture nonunion. MRI confirms avascular necrosis of the proximal pole, but radiographs show no carpal collapse or degenerative changes. What is the most appropriate surgical management?

Explanation

For a scaphoid nonunion complicated by avascular necrosis of the proximal pole without significant radioscaphoid arthritis or carpal collapse, a vascularized bone graft (e.g., 1,2-ICSRA graft) combined with rigid internal fixation provides the highest rate of bony union.

Question 83

A 68-year-old woman presents with severe lateral hip pain and an unremitting limp 2 years after a total hip arthroplasty via a direct lateral approach. Physical examination reveals a profound Trendelenburg lurch. MRI with metal suppression demonstrates a massive, retracted tear of the gluteus medius and minimus tendons with fatty infiltration. What is the most appropriate surgical management?

Explanation

For chronic, massive, retracted abductor tendon tears with fatty infiltration post-THA, primary repair is often doomed to fail. A gluteus maximus muscle flap transfer or Achilles tendon allograft reconstruction is the procedure of choice to restore function.

Question 84

A 25-year-old man is brought to the emergency department after a motorcycle collision. Radiographs demonstrate symphyseal widening of 3.5 cm and widening of the anterior sacroiliac joints bilaterally. The posterior sacroiliac ligaments are intact. According to the Young-Burgess classification, which of the following ligaments is ruptured?

Explanation

This is an APC-II pelvic ring injury (symphyseal widening greater than 2.5 cm with anterior SI joint widening). It is characterized by rupture of the symphyseal, anterior sacroiliac, sacrospinous, and sacrotuberous ligaments, while the strong posterior sacroiliac ligaments remain intact.

Question 85

A 30-year-old man is involved in a motor vehicle accident. Cervical spine CT reveals a fracture through the pars interarticularis of C2 bilaterally. Flexion-extension radiographs show severe angulation with minimal translation, and the angulation increases upon application of traction. What is the recommended treatment for this specific fracture pattern?

Explanation

A Levine-Edwards Type IIa Hangman's fracture is characterized by severe angulation with minimal translation and is caused by flexion-distraction. Traction is contraindicated as it exacerbates the deformity; treatment requires gentle reduction with slight compression and extension followed by halo vest immobilization.

Question 86

During the surgical reconstruction of a torn posterior cruciate ligament (PCL), the surgeon must accurately reproduce the native anatomy. Which of the following best describes the anatomical femoral footprint and tensioning pattern of the anterolateral (AL) bundle of the PCL?

Explanation

The PCL originates on the anterolateral aspect of the medial femoral condyle. The larger anterolateral (AL) bundle is tightest in knee flexion, whereas the smaller posteromedial (PM) bundle is tightest in knee extension.

Question 87

A 28-year-old construction worker falls onto an outstretched hand and presents with severe volar wrist swelling. Radiographs reveal a volar displacement of the lunate, appearing as a 'spilled teacup' on the lateral view, while the capitate remains aligned with the radius. What is the sequence of carpal instability leading to this injury according to Mayfield's stages?

Explanation

According to Mayfield's progressive perilunate instability, the sequence is Stage I (scapholunate), Stage II (capitolunate), Stage III (lunotriquetral), and Stage IV (failure of the dorsal radiocarpal ligament). This final stage allows the lunate to dislocate volarly into the carpal tunnel.

Question 88

A 5-year-old child presents with frequent bone fractures, cranial nerve palsies, and diffuse osteosclerosis on radiographs. A genetic defect impairing the acidification of the osteoclast resorption pit is suspected. Which of the following enzymes or proteins is most likely deficient?

Explanation

Osteopetrosis is caused by defective osteoclast function. A deficiency in Carbonic anhydrase II impairs the osteoclast's ability to secrete protons and acidify the resorption pit, which is absolutely necessary for breaking down the inorganic bone matrix.

Question 89

A 12-year-old boy is diagnosed with a severe, chronic left slipped capital femoral epiphysis (SCFE). Which of the following is the most widely accepted absolute indication for prophylactic in-situ pinning of the asymptomatic contralateral hip?

Explanation

Prophylactic pinning of the contralateral hip is highly recommended in patients with endocrine or metabolic disorders (e.g., hypothyroidism, renal osteodystrophy) due to the exceptionally high risk of bilateral involvement. Age less than 10 years or open triradiate cartilage are also strong relative indications.

Question 90

A 65-year-old man presents with chronic, progressively worsening thigh pain. Radiographs of the femur demonstrate a destructive diaphyseal lesion with stippled, 'popcorn-like' calcifications and endosteal scalloping greater than 2/3 of the cortical thickness. Biopsy reveals atypical chondrocytes in a hyaline cartilage matrix. What is the most appropriate management?

Explanation

The clinical and radiographic findings are classic for a conventional chondrosarcoma. Conventional chondrosarcomas are notoriously resistant to both chemotherapy and radiation, making wide surgical resection the mainstay of treatment.

Question 91

A 24-year-old athlete sustains a hyperplantarflexion injury to his foot. Weight-bearing radiographs show a 3 mm diastasis between the base of the first and second metatarsals. An MRI confirms a complete rupture of the Lisfranc ligament. Which of the following accurately describes the anatomy of this ligament?

Explanation

The Lisfranc ligament is a strong interosseous ligament that connects the lateral aspect of the medial cuneiform to the medial base of the second metatarsal. It is critical for the stability of the midfoot and is located on the plantar aspect of the joint.

Question 92

A 45-year-old woman falls on her outstretched arm and sustains a 'terrible triad' injury of the elbow. During surgical reconstruction, after addressing the radial head fracture, the lateral ulnar collateral ligament (LUCL) must be repaired. What is the primary anatomical origin and insertion of the LUCL?

Explanation

The lateral ulnar collateral ligament (LUCL) is the primary restraint to posterolateral rotatory instability (PLRI) of the elbow. It originates from the lateral epicondyle of the humerus and inserts distally on the supinator crest of the proximal ulna.

Orthopedic Prometric Exam Preparation MCQs - Part 1

Orthopedic Prometric Exam Preparation MCQs - Part 16

Orthopedic Prometric Exam Preparation MCQs - Part 16

Chapter Index