Question 1

A 12-year-old boy comes to your office 2 weeks after a distal radius physeal fracture, which has been splinted in the emergency department. The epiphysis is displaced dorsally by 50%, and the articular surface has a dorsal tilt of 17°. You recommend:

Explanation

Distal radial physeal fractures are common injuries. Reduction should be done gently and not repeated multiple times. Fractures presenting late like this one are difficult to manipulate atraumatically, but have good remodeling potential. Therefore, a cast should be applied to limit any further displacement, but no manipulation or operation is recommended.

Question 2

Which of the following lowers the chance of a good result from stretching of muscular torticollis in infants:

Explanation

Stretching produces good results in more than 90% of infants. Presence of a palpable mass in the sternomastoid predicts a lower success rate than absence of such a mass. The other factors are either positive or neutral.

Question 3

A 14-year-old boy suffers a hip dislocation in a motor vehicle accident. It is reduced by closed means. The risk of avascular necrosis is:

Explanation

Avascular necrosis is a risk of traumatic hip dislocation. The risk is closest to 10%.

Question 4

Which of the following statements is true of the King classification of idiopathic scoliosis:

Explanation

The Lenke system is more comprehensive than the King system, for the latter considers the entire range or thoracolumbar and lumbar curve possibilities, as well as the sagittal plane. The Lenke system also appears to have a higher interobserver reliability.

Question 5

The most common form of chondrodysplasia punctata is much more common in girls than in boys. Which of the following explains this:

Explanation

X-linked dominant inheritance would explain the preponderance of girls with this condition, because they have twice as great a chance of having an affected x-chromosome. One affected x-chromosome is sufficient to convey the disease in a dominant condition. The imprinting phenomenon refers to a condition that varies depending upon whether the mother or the father passed it on (as in Angelman versus Prader-Willi syndromes).

Question 6

A 9-year-old boy injures his elbow in a fall from a 12-foot height. Radiographs reveal a posterior dislocation of the elbow with a fracture of the medial epicondyle which is displaced. The ossification center is 5 mm in diameter. You recommend:

Explanation

A recent long-term study has shown that open reduction of displaced medial epicondyle fractures does not yield superior results to closed treatment. This applies even when the elbow is initially dislocated. Excision of the epicondyle with suture of the ligament yields the highest incidence of late problems, such as flexion contractures and degenerative changes.

Question 7

The most accurate and practical means of determining pregnancy status in adolescent females undergoing surgery is:

Explanation

Anesthesia and surgery can be detrimental to a fetus, especially during the first trimester. Patient self-report is not accurate in many cases. Immunospot testing of the first morning urine for human chorionic gonadotropin is 99.4% sensitive and specific, rapid, and inexpensive. Serum HC G testing is less rapid and more expensive; therefore, not appropriate for surgical screening. The other tests are not used to ascertain pregnancy status.

Question 8

Which of the following is considered a critical element in surgically correcting posttraumatic elbow flexion contractures in adolescents:

Explanation

Bae and Waters have shown that adolescents with significant posttraumatic elbow flexion contractures can gain an average of 54° of motion with surgical release. They believe postoperative physical therapy and continuous passive motion are considered critical to success of surgical release. Lengthening of the biceps or triceps is not recommended. Measures to prevent postoperative heterotopic ossification did not influence the outcome.

Question 9

Which of the following statements is true concerning atlanto-occipital dislocations in children:

Explanation

Pediatric atlanto-occipital dislocation is increasing in frequency due to improved emergency care. Although the injuries are sometimes fatal and are often accompanied by severe spinal cord injury, this is not always the case. Although the dens-basion distance should be less than 10 mm and the power ratio should be less than 1 in normals, these are not always abnormal in children with such injuries. Clinical and radiographic correlation, with computer tomography or magnetic resonance imaging if needed, are called for to maximize diagnosis.

Question 10

Equinovarus positioning of the foot is normal during which stage of embryonic life:

Explanation

As the foot matures, it passes through a normal stage when it resembles a clubfoot in the eighth to tenth week. After this, the foot normally corrects itself.

Question 11

Which of the following is a similarity between congenital pseudarthrosis of the clavicle and congenital pseudarthrosis of the tibia:

Explanation

Congenital pseudarthrosis of the clavicle and tibia may present in infants with a gap between two tapered, atrophic bone ends. However, they are dissimilar in other respects. Pseudarthrosis of the clavicle is seen almost exclusively on the right side, while that of the tibia is seen on either side. Pseudarthrosis of the clavicle may be seen in cleidocranial dysostosis, although tibial pseudarthrosis is not. Pseudarthrosis of the clavicle has a high rate of union with simple bone graft, while that of the tibia does not. One-half of patients with pseudarthrosis of the tibia have neurofibromatosis, while this is almost never seen in congenital pseudarthrosis of the clavicle.

Question 12

A 13-year-old boy has a left slipped capital femoral epiphysis which has displaced 75%. He is unable to bear weight on the limb. The other hip has no clinical or radiographic abnormalities. Your preferred treatment is which of the following:

Explanation

This is an unstable slip. It has a much higher chance of avascular necrosis than a stable slip. Since the degree of the slip will increase the shear forces across the healing physis and decrease the function of the hip, some method of improving this is justified. Gentle reduction of the epiphysis, without forceful internal rotation, may increase the risk of avascular necrosis. Avascular necrosis is a significant risk in many series of cuneiform (metaphyseal; Fish) osteotomies. Subtrochanteric osteotomy is not justified in patients with an acute slip until it is healed. It has a high rate of chondrolysis. Free vascularized bone graft may be an option if avascular necrosis develops, but is not indicated at this time. A hip spica cast is also often followed by chondrolysis and delayed epiphyseodesis.

Question 13

Of all slipped capital femoral epiphyses, which percentage is unstable:

Explanation

Unstable slipped capital femoral epiphysis places the patient at a high risk of avascular necrosis (up to 47%). Fortunately, it comprises only about 5% of all slips.

Question 14

The normal value for the hallux valgus angle is:

Explanation

The angle between the first metatarsal and its proximal phalanx is normally one of mild (10° to 20°) valgus. It is not normal for it to be too straight. An increase in this angle beyond this value is often noted by the patient as a bunion.

Question 15

A 13-year-old girl is seen in clinic for bunion. She is asymptomatic but has a hallux valgus angle of 29°, an intermetatarsal angle of 15°, and a medial prominence over the first metatarsal head. The family asks whether anything can be done to prevent future problems with the foot. You recommend:

Explanation

Bunions may often be treated conservatively, and it is impossible to predict which ones will later develop symptoms. Surgical reconstruction of bunions in adolescents has a higher rate of recurrence than in adults in many reported series. For all of these reasons, nonoperative treatment is preferred for asymptomatic patients.

Question 16

Which of the following tendons is not usually contracted in a patient with untreated vertical talus:

Explanation

A vertical talus is a fixed dorsolateral dislocation of the talonavicular joint. The forefoot is in calcaneus and the hindfoot is in equinus. Therefore, all of the tendons listed except for the posterior tibialis are contracted.

Question 17

A 9-year-old boy is seen because of pain medially, in the arch of the foot. His ankle dorsiflexion is limited to 10Â° with the knee extended. Radiograph shows an accessory navicular, which corresponds to the point of his tenderness. You recommend:

Explanation

Accessory navicular is seen in 10% to 14% of normal children. Sometimes, it becomes symptomatic in juveniles or adolescents, but this usually resolves by skeletal maturity. Conservative treatment, such as activity restriction, arch support, and stretching the Achilles if tight, will usually alleviate symptoms.

Question 18

Which of the following disorders is due to a defect in anterior horn cells:

Explanation

Charcot-Marie-Tooth disease is due to a defect in peripheral nerves; Duchenne muscular dystrophy is due to a defect in dystrophin, affecting the muscle cell membrane; Friedreich ataxia is a degeneration of the spinocerebellar tracts. Rett syndrome is due to a defect in MEC P-2 protein, affecting the brain. Only spinal muscular atrophy is due to a defect in anterior horn cells.

Question 19

Becker muscular dystrophy is due to a defect in the gene for which of the following:

Explanation

Becker muscular dystrophy has a defect in the same gene as Duchenne muscular dystrophy, namely the protein dystrophin. The mutation in Becker dystrophy results in a truncated protein that retains some function, whereas the mutation in Duchenne dystrophy is different and results in an unstable protein, which is degraded quickly.

Question 20

Which of the following muscles is first affected in facioscapulohumeral dystrophy:

Explanation

In facioscapulohumeral dystrophy, the facial muscles are affected first, commonly presenting with an inability to whistle. The serratus muscles and scapular stabilizers are affected next. The deltoid, supraspinatus, and infraspinatus are typically not affected in this disease.

Question 21

Emery-Dreifuss muscular dystrophy is unique among the dystrophies because of the development of which deformity:

Explanation

Emery-Dreifuss muscular dystrophy is an x-linked disorder of emerin, which is a cell-membrane protein. Symptoms and signs develop within the first decade in most cases. A unique deformity, neck extension contracture, develops, in addition to elbow flexion contractures and peroneal wasting. The other deformities listed above are common in many dystrophies.

Question 22

Electrodiagnostic testing in myopathies typically shows all of the following except:

Explanation

Electrodiagnostic testing in myopathy typically shows low amplitude, polyphasic EMG potentials with a decreased duration of response. Nerve conduction velocity is normal, in contrast to findings in neuropathies. Fibrillations are not typically seen; these are more characteristic of neuropathy.

Question 23

In which region is direct anatomical extension from the metaphysis of a long bone to the adjacent joint not anatomically possible in the child:

Explanation

The metaphysis of the proximal humerus lies partially within the shoulder joint; similarly, that of the proximal radius lies within the elbow. The metaphysis of the proximal femur lies within the hip joint and that of the distal lateral tibia within the ankle joint. There is no intra-articular metaphysis about the knee, however.

Question 24

Which of the following skeletal dysplasias is not commonly associated with non-orthopedic complications:

Explanation

McKusick dysplasia is commonly associated with immune and gastrointestinal disorders. Hurler syndrome is associated with progressive mental retardation, hepatosplenomegaly, and cataracts. Morquio syndrome is associated with cardiorespiratory difficulties. C hondroectodermal dysplasia, or Ellis van C reveld syndrome, is associated with congenital heart disease. Multiple epiphyseal dysplasia, however, is not associated with systemic non- orthopaedic complications.

Question 25

Which of the following by itself is not an indication for surgery in a child with acute hematogenous osteomyelitis:

Explanation

Surgery is indicated in situations in which antibiotics alone will not be curative, including subperiosteal abscess, sequestrum, intramedullary abscess, and adjacent septic arthritis. Fever alone is not an indication for surgery.

Question 26

Which of the following is not usually seen in chronic recurrent multifocal osteomyelitis:

Explanation

Chronic recurrent multifocal osteomyelitis is believed to be an idiopathic noninfectious inflammatory disease. It has gradual onset of symptoms, and sites most commonly involved are the spine, long bones, and feet. Nonsteroidal anti-inflammatory drugs typically improve symptoms. Cultures are negative.

Question 27

A 5-year-old child is bitten by a tick. Which of the following has been shown to aid in management:

Explanation

Prompt tick removal is recommended because Lyme disease is more likely if the tick is attached for more than 24 hours. Immediate antibiotic administration is not recommended because the incidence of Lyme disease is low after any single tick bite and treatment is equally effective once the disease is diagnosed. Doxycycline is not recommended in children younger than 8 years old because of dental discoloration. Immediate testing for antibodies (ELISA) is not useful because antibodies do not rise for at least several weeks. Steroids are not recommended in this setting.

Question 28

Which of the following measures has not been shown to decrease rates of injury in healthy children participating in recreational sports:

Explanation

Knee braces have been shown not to reduce injury rates for children for children with sound knees. All other measures have been shown to reduce injury rates.

Question 29

Which recreational activity causes the most musculoskeletal injuries in children ages 5 to 14 in the United States:

Explanation

Bicycles are the leading cause of musculoskeletal injury in American children, with 415,000 injuries per year, followed by basketball, football, and roller sports.

Question 30

The effects of pediatric orthopedic conditions in later adulthood commonly determine treatment choices for children. At what threshold does limb length discrepancy increase the energy cost of walking in older adults:

Explanation

A limb length discrepancy of as little as 2 cm has shown to increase perceived exertion as well as oxygen consumption in older adults.

Question 31

Anterior elbow release in children with cerebral palsy is likely to result in which of the following outcomes:

Explanation

Anterior elbow release consists of lengthening of the lacertus fibrosus and the brachialis fascia. It may or may not include lengthening of the biceps tendon itself. Anterior elbow release effectively decreases the excessive flexion posture of the elbow during use, which one author has termed the â flexion posture angle.â It does not result in decreased (or increased) strength of elbow flexion if the biceps tendon is preserved. Unfortunately, increased use during bimanual activity and increased grip strength are usually not observed.

Question 32

Which of the following procedures is most likely to correct idiopathic toe walking with a single treatment:

Explanation

Percutaneous tendoachilles lengthening is most likely to resolve idiopathic toe walking in a single treatment. The other methods have a higher likelihood of persistent toe walking.

Question 33

Core binding factor alpha 1 (C bfa1) is a transcription factor having which of the following effects:

Explanation

Cbfa1 is a transcription factor that causes cells to differentiate into osteoblasts. An abnormality in its gene causes cleidocranial dysplasia.

Question 34

Which of the following is found less often in children with lumbosacral agenesis as compared to controls:

Explanation

Patients with lumbosacral agenesis often have knee flexion contractures as compared with controls. All of the other features listed are common in patients with lumbosacral agenesis.

Question 35

Which of the following figures most closely approximates the prevalence of defects in the L5 pars interarticularis in a newborn:

Explanation

Pars interarticularis defects are not found in newborns, whereas the incidence is 5% in patients who are in the first grade. It remains close to this figure throughout later life.

Question 36

Which of the following is the most common cause of low back pain in young athletes:

Explanation

Spondylolysis is the most common cause of back pain in young athletes, accounting for approximately 50% of cases. The other causes are significantly less common.

Question 37

A 7-year-old boy with cerebral palsy, total involvement type, has neuromuscular hip dysplasia. The migration index is 60% without flattening. He has had pain in the groin for the past 6 months. Recommended treatment includes:

Explanation

Pain in the spastic patient with subluxation without head deformity is most appropriately treated by reduction. Adductor tenotomy alone is not recommended when the hip subluxation exceeds 50% or the age is greater than 5 to 6 years. Femoral osteotomy should be added. Salvage procedures such as proximal femoral resection, arthrodesis, or arthroplasty are not indicated.

Question 38

A 5-year-old child presents with a pulseless, pink hand following a displaced supracondylar humerus fracture. After closed reduction and percutaneous pinning, the hand remains pink but pulseless. What is the next most appropriate step in management?

Explanation

A pulseless, pink hand after reduction of a pediatric supracondylar humerus fracture indicates adequate collateral circulation and is generally managed with observation. Immediate vascular exploration is reserved for a hand that remains pulseless and pale despite reduction.

Question 39

A 65-year-old woman presents with persistent groin pain 1 year after an uncemented total hip arthroplasty. Radiographs show a radiolucent line in DeLee and Charnley zone 3 of the acetabulum, with no progression over 6 months. Bone scan reveals isolated increased uptake at the distal tip of the femoral stem. What is the most likely diagnosis?

Explanation

Thigh pain is a known complication of uncemented femoral stems, particularly those with a large diameter causing modulus mismatch. Distal tip uptake on a bone scan is characteristic, whereas non-progressive zone 3 lucency is likely a stable finding.

Question 40

During reconstruction of the anterior cruciate ligament (ACL), drilling the femoral tunnel too anteriorly (shallow in the notch) will result in which of the following biomechanical consequences?

Explanation

A femoral tunnel placed too anteriorly (high in the notch) results in a graft that becomes excessively tight in flexion, potentially limiting knee flexion. It remains relatively loose in extension, compromising stability.

Question 41

A 45-year-old man sustains an APC-III (Anteroposterior Compression III) pelvic ring injury. Which of the following ligaments must be disrupted to classify this injury as an APC-III rather than an APC-II?

Explanation

In the Young-Burgess classification, an APC-II injury involves disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments. An APC-III injury includes complete disruption of the posterior sacroiliac ligament, leading to complete spinopelvic instability.

Question 42

A 15-year-old boy presents with knee pain. Radiographs reveal a sunburst periosteal reaction and Codman's triangle in the distal femur. Biopsy confirms osteosarcoma. What is the most significant prognostic factor for long-term survival in this patient?

Explanation

The most critical prognostic factor for localized osteosarcoma is the histological response to neoadjuvant chemotherapy. Greater than 90% tumor necrosis is associated with significantly improved long-term overall survival.

Question 43

A 30-year-old carpenter sustains a volar laceration to his dominant index finger, severing both the FDS and FDP tendons in Zone II. Following primary repair of both tendons, what rehabilitation protocol best minimizes the risk of tendon rupture while preventing adhesion formation?

Explanation

Protocols like the modified Kleinert or Duran utilize a dorsal block splint to prevent excessive extension while allowing passive flexion and active extension. This glides the tendons, preventing adhesions while protecting the newly repaired tissue.

Question 44

A 65-year-old man with progressive cervical spondylotic myelopathy presents with difficulty buttoning his shirts and a wide-based gait. Examination reveals hyperreflexia. Which of the following physical exam findings is most specific for cervical myelopathy at the C5-C6 level?

Explanation

The inverted radial reflex (finger flexion upon tapping the brachioradialis tendon) is a highly specific sign of cervical spondylotic myelopathy at C5-C6. It indicates a lower motor neuron lesion at C5 and an upper motor neuron lesion below that level.

Question 45

Which of the following statements best describes the mechanism of primary (direct) bone healing?

Explanation

Primary bone healing occurs under conditions of absolute stability and no fracture gap. It utilizes Haversian remodeling where osteoclasts create cutting cones followed by osteoblasts, circumventing callus formation.

Question 46

A 25-year-old athlete sustains a hyperplantarflexion injury to his midfoot. Weight-bearing radiographs show a 3mm diastasis between the base of the first and second metatarsals. Which of the following best describes the anatomy of the Lisfranc ligament?

Explanation

The Lisfranc ligament is a stout interosseous ligament that connects the lateral aspect of the medial cuneiform to the medial aspect of the base of the second metatarsal. It is critical for the stability of the tarsometatarsal articulation.

Question 47

An overweight 13-year-old boy presents with left knee pain and a limp. Examination reveals obligate external rotation of the hip during passive flexion. Following diagnosis of a stable slipped capital femoral epiphysis (SCFE), what is the most appropriate surgical treatment?

Explanation

The gold standard treatment for a stable slipped capital femoral epiphysis is in situ pinning with a single cannulated screw placed in the center of the epiphysis. Attempts at closed reduction significantly increase the risk of avascular necrosis.

Question 48

During a total knee arthroplasty, the surgeon notices that the knee is tight in flexion but stable and balanced in extension. Which of the following is the most appropriate step to correct this mismatch?

Explanation

A knee that is tight in flexion but balanced in extension has an isolated tight flexion gap. This can be addressed by downsizing the femoral component (to reduce posterior condylar offset) or increasing the posterior slope of the tibia.

Question 49

A 40-year-old man sustains a Schatzker VI tibial plateau fracture. Which of the following neurovascular structures is at the highest risk of injury during a posteromedial surgical approach to the proximal tibia?

Explanation

The posteromedial approach to the proximal tibia exploits the interval between the medial gastrocnemius and the pes anserinus. The great saphenous vein and saphenous nerve lie in the superficial fascia of this region and are highly susceptible to injury.

Question 50

A 22-year-old man presents with anatomic snuffbox tenderness after a fall onto an outstretched hand. Initial radiographs are negative. An MRI obtained 1 week later confirms an undisplaced fracture of the proximal pole of the scaphoid. What is the blood supply most relevant to the high nonunion risk of this fracture?

Explanation

The scaphoid receives its primary blood supply from the dorsal carpal branch of the radial artery, which enters distally and flows retrograde. This delicate retrograde flow makes proximal pole fractures highly susceptible to avascular necrosis and nonunion.

Question 51

A 65-year-old man presents with a pathologic subtrochanteric femur fracture. Laboratory workup reveals hypercalcemia, renal insufficiency, and anemia. Serum protein electrophoresis shows an M-spike. Which of the following radiographic findings is most characteristic of this patient's underlying disease?

Explanation

The patient's clinical presentation is classic for multiple myeloma. The characteristic radiographic appearance includes multiple "punched-out" lytic bone lesions lacking a reactive sclerotic rim due to simultaneous osteoclast activation and osteoblast inhibition.

Question 52

A 20-year-old collegiate wrestler undergoes an arthroscopic Bankart repair. During the procedure, an engaging Hill-Sachs lesion is noted that drops into the glenoid rim in abduction and external rotation. Which of the following procedures should be added to prevent recurrence?

Explanation

An engaging Hill-Sachs lesion can lever the humeral head out of the glenoid, leading to failure of an isolated Bankart repair. The arthroscopic remplissage procedure tenodeses the infraspinatus tendon into the defect, converting it to an extra-articular non-engaging lesion.

Question 53

A 35-year-old man sustains a closed midshaft tibia fracture. He develops excruciating leg pain out of proportion to the injury, exacerbated by passive stretch of the hallux. Which absolute pressure or differential pressure threshold is the most widely accepted indication for immediate fasciotomy?

Explanation

The most reliable indicator for acute compartment syndrome is the delta pressure (Δp). A difference of less than 30 mmHg between the diastolic blood pressure and the intracompartmental pressure is a widely accepted indication for surgical decompression.

Question 54

A 45-year-old woman falls from a height and sustains an L1 burst fracture. She is neurologically intact. Which of the following radiographic findings is a classic indicator of posterior ligamentous complex (PLC) injury, potentially warranting surgical stabilization?

Explanation

Widening of the interspinous distance on an AP or lateral radiograph suggests tension failure and disruption of the posterior ligamentous complex (PLC). PLC incompetence renders a burst fracture mechanically unstable, often necessitating surgical stabilization.

Question 55

Which of the following is an absolute indication for prophylactic in situ fixation of the contralateral hip in a patient with a unilateral Slipped Capital Femoral Epiphysis (SCFE)?

Explanation

Patients with underlying endocrine disorders (such as hypothyroidism), prior radiation, or renal failure have an exceptionally high risk of contralateral slip. In these populations, prophylactic pinning of the unaffected hip is strongly recommended.

Question 56

A 6-year-old child presents with a widely displaced extension-type supracondylar fracture of the humerus. Which nerve is most commonly injured in this specific fracture pattern?

Explanation

The anterior interosseous nerve (AIN) is the most frequently injured nerve in extension-type pediatric supracondylar humerus fractures. Its motor function is tested clinically by asking the patient to make an "OK" sign.

Question 57

A 30-year-old man sustains a completely displaced, vertically oriented femoral neck fracture (Pauwels type III). What is the preferred surgical treatment to minimize the risk of nonunion?

Explanation

In young adults with vertical, shear-pattern (Pauwels III) femoral neck fractures, a sliding hip screw (often supplemented with a derotational screw) provides superior biomechanical stability against shear forces compared to multiple cancellous screws.

Question 58

A 14-year-old boy presents with progressive knee pain. Radiographs reveal a metaphyseal permeative lesion in the distal femur with a "sunburst" periosteal reaction. Biopsy shows malignant spindle cells producing unmineralized osteoid. What is the most likely diagnosis?

Explanation

The production of osteoid by malignant mesenchymal cells is the histological hallmark of osteosarcoma. A "sunburst" periosteal reaction in the metaphysis of a teenager further supports this diagnosis over Ewing sarcoma.

Question 59

A 22-year-old soccer player sustains a twisting injury to the knee. Radiographs reveal a small avulsion fracture of the lateral tibial plateau. This radiographic finding is most highly associated with an injury to which of the following structures?

Explanation

A Segond fracture is an avulsion of the anterolateral ligament complex from the lateral tibial plateau. It is considered a pathognomonic radiographic sign for an anterior cruciate ligament (ACL) tear.

Question 60

A 45-year-old man is involved in a motor vehicle accident. CT scan shows a bilateral fracture of the C2 pars interarticularis with 2 mm of displacement and no angulation. Neurological examination is normal. What is the most appropriate management?

Explanation

A Levine-Edwards Type I Hangman's fracture involves bilateral pars interarticularis fractures with less than 3 mm of displacement and no angulation. It is a stable injury that is appropriately managed non-operatively with a rigid cervical collar.

Question 61

A 28-year-old man presents with chronic wrist pain. Radiographs show a scaphoid waist nonunion with a "humpback" deformity and dorsal intercalated segment instability (DISI). What is the recommended surgical management?

Explanation

A humpback deformity in a scaphoid nonunion indicates volar bone loss resulting in carpal collapse. A volar structural wedge bone graft with internal fixation is required to restore scaphoid length and correct the DISI alignment.

Question 62

A 6-month-old infant is diagnosed with developmental dysplasia of the hip (DDH) that has failed Pavlik harness treatment. An ultrasound confirms persistent dislocation. What is the next most appropriate step in management?

Explanation

After failure of a Pavlik harness, or if diagnosed between 6 and 18 months of age, closed reduction under general anesthesia followed by spica casting is the standard next step in DDH management.

Question 63

A 4-year-old boy presents with acute limp and fever of 38.8 C (101.8 F). ESR is 45 mm/hr, serum WBC is 14,000/mm3, and he refuses to bear weight. According to Kocher's criteria, what is the approximate probability that this child has septic arthritis?

Explanation

The Kocher criteria for pediatric septic arthritis of the hip include non-weight bearing, temperature >38.5 C, ESR >40, and WBC >12,000. Having all 4 predictors yields a 99% predictive probability for septic arthritis.

Question 64

A 35-year-old man with a highly comminuted closed tibia fracture complains of severe pain worsened by passive stretch of the hallux. Intracompartmental pressure is 35 mmHg and diastolic blood pressure is 60 mmHg. What is the most appropriate next step?

Explanation

Clinical signs combined with a delta pressure (diastolic BP minus compartment pressure) of less than 30 mmHg confirm acute compartment syndrome. Emergent four-compartment fasciotomy is mandatory to prevent irreversible tissue necrosis.

Question 65

A 30-year-old carpenter lacerates the volar aspect of his index finger between the distal palmar crease and the proximal interphalangeal joint, transecting the FDS and FDP tendons. This injury is located in which flexor tendon zone?

Explanation

Flexor tendon Zone II, historically known as "no man's land," extends from the A1 pulley at the distal palmar crease to the FDS insertion on the middle phalanx. Injuries here involve both flexor tendons within the tight fibro-osseous sheath.

Question 66

A 55-year-old patient with poorly controlled type 2 diabetes presents with a swollen, erythematous right foot. Radiographs show fragmentation, periarticular debris, and subluxation at the tarsometatarsal joints. Which Eichenholtz stage describes these findings?

Explanation

Eichenholtz Stage I (Development/Fragmentation) of Charcot arthropathy is characterized by acute inflammation, bone fragmentation, joint subluxation, and debris. Stage II is coalescence, and Stage III is reconstruction.

Question 67

During secondary fracture healing, the transition from a soft cartilaginous callus to a hard bony callus is primarily mediated by which of the following processes?

Explanation

In secondary fracture healing, the soft callus composed primarily of cartilage is converted into a woven bone hard callus via endochondral ossification. This process is dependent on adequate mechanical stability and blood supply.

Question 68

An 8-year-old boy is diagnosed with Legg-Calve-Perthes disease. Which of the following radiographic findings is recognized as a "head-at-risk" sign according to Catterall?

Explanation

Catterall's "head-at-risk" signs indicate a poorer prognosis in Perthes disease. They include lateral subluxation, Gage's sign, calcification lateral to the epiphysis, diffuse metaphyseal reactions (cysts), and a horizontal growth plate.

Question 69

A 65-year-old man with hypercalcemia and an M-spike on protein electrophoresis has multiple "punched-out" skull lesions. Which is the most appropriate initial screening test to evaluate for impending pathologic appendicular fractures?

Explanation

Multiple myeloma lesions are purely lytic and often lack an osteoblastic response, leading to "cold" or false-negative results on a bone scan. A complete plain radiographic skeletal survey is the standard initial imaging modality.

Question 70

A 24-year-old male sustains recurrent anterior shoulder dislocations. Imaging demonstrates an engaging Hill-Sachs lesion and 25% bone loss of the anterior inferior glenoid. What is the most appropriate surgical intervention?

Explanation

In patients with recurrent anterior shoulder instability and significant anterior glenoid bone loss (>20-25%), isolated soft tissue repairs have unacceptably high failure rates. A bony augmentation procedure, such as the Latarjet (coracoid transfer), is required.

Question 71

Six weeks after a total knee arthroplasty, a patient presents with a painful, stiff knee. Aspiration yields 35,000 WBC/uL (90% neutrophils). Radiographs show well-fixed implants. What is the most appropriate management?

Explanation

For acute periprosthetic joint infections (occurring <4 weeks post-op or <3 weeks of symptom onset) with well-fixed implants, open debridement, antibiotics, and implant retention (DAIR) with polyethylene exchange is the standard of care.

Question 72

During an anterolateral (Watson-Jones) approach to the hip, the superficial surgical interval is developed between which two muscles?

Explanation

The Watson-Jones (anterolateral) approach utilizes the muscular interval between the tensor fasciae latae and the gluteus medius. Although both are innervated by the superior gluteal nerve, it is a safe and widely used plane for hip exposure.

Question 73

In the Ponseti method for correcting idiopathic clubfoot, which deformity is the first to be addressed during serial casting?

Explanation

The Ponseti method dictates that the cavus deformity must be corrected first by elevating the first metatarsal to align the forefoot with the hindfoot. Adduction and varus are corrected next, with equinus corrected last.

Question 74

A 40-year-old male sustains an anteroposterior compression (APC) III pelvic ring injury. He remains hemodynamically unstable despite a pelvic binder and fluid resuscitation. FAST exam is negative. What is the most appropriate next step?

Explanation

In a hemodynamically unstable patient with a mechanically unstable pelvic fracture and no evidence of intra-abdominal bleeding, the source of shock is likely pelvic vascular injury. Preperitoneal packing and/or angioembolization are critical to achieve hemostasis.

Question 75

A 15-year-old male presents with persistent low back pain due to a grade II L5-S1 isthmic spondylolisthesis. Conservative management with physical therapy and bracing has failed over the past 6 months. What is the most appropriate surgical treatment?

Explanation

Posterior in situ posterolateral fusion is the gold standard for symptomatic, low-grade (Grade 1 and 2) isthmic spondylolisthesis that fails conservative care. Pars repair is typically reserved for younger patients with a pars defect but no significant slip (Grade 0).

Question 76

A 35-year-old man sustains a Gustilo-Anderson IIIB open tibia fracture following a motorcycle accident. After aggressive initial debridement, timing of soft tissue flap coverage is planned. For the lowest rate of deep infection, soft tissue coverage should ideally be performed within:

Explanation

Soft tissue coverage for Gustilo IIIB open fractures performed within 72 hours is associated with the lowest rates of deep infection and flap failure. Delaying beyond this window significantly increases infection risk.

Question 77

A 62-year-old woman with a metal-on-metal total hip arthroplasty presents with groin pain and mechanical symptoms. MRI reveals a solid soft-tissue pseudotumor. Histological examination of the periprosthetic tissue is most likely to show:

Explanation

Metal-on-metal wear debris can incite a specific delayed-type hypersensitivity reaction. Histologically, this is characterized by perivascular lymphocytic infiltration, known as an aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL).

Question 78

Six months after an anterior cruciate ligament (ACL) reconstruction utilizing a bone-patellar tendon-bone autograft, a patient complains of an audible "clunk" and lack of terminal extension. MRI shows a nodular mass anterior to the tibial tunnel. This lesion is predominantly composed of:

Explanation

The patient is presenting with a "Cyclops" lesion, which causes mechanical impingement and loss of terminal extension post-ACL reconstruction. Pathologically, it is a localized nodule of dense fibrovascular tissue.

Question 79

In the rehabilitation following a primary Zone II flexor tendon repair, which of the following postoperative protocols has been shown to result in the strongest tendon healing and the fewest adhesions?

Explanation

Early active mobilization protocols place controlled stress on the healing tendon, which promotes intrinsic healing, increases tensile strength, and reduces the formation of restrictive peritendinous adhesions.

Question 80

A 12-year-old obese boy presents with a unilateral slipped capital femoral epiphysis (SCFE). Prophylactic in situ pinning of the contralateral asymptomatic hip is most strongly recommended if the patient has a concurrent history of:

Explanation

Prophylactic pinning of the contralateral hip is indicated in patients at high risk for bilateral disease. This includes those with endocrine disorders (e.g., hypothyroidism) and metabolic bone disease such as renal osteodystrophy.

Question 81

A 16-year-old male presents with distal thigh pain. Radiographs reveal a destructive metaphyseal lesion with a "sunburst" periosteal reaction. A core needle biopsy confirms high-grade osteosarcoma. Which of the following is the most critical prognostic factor for his overall survival?

Explanation

The histologic response to neoadjuvant chemotherapy is the single most important prognostic factor in high-grade osteosarcoma. A response of greater than 90% tumor necrosis correlates with significantly improved long-term survival.

Question 82

Which of the following metallic orthopedic implant materials has a modulus of elasticity closest to that of cortical bone?

Explanation

Titanium alloy has a modulus of elasticity of approximately 110 GPa, which is closest to cortical bone (15-20 GPa) among standard solid implant metals. This reduces the effect of stress shielding compared to stiffer metals like cobalt-chromium (210 GPa) or stainless steel (200 GPa).

Question 83

A 55-year-old diabetic patient presents with a warm, swollen, erythematous left foot. Radiographs show no fractures or joint subluxation. MRI demonstrates diffuse marrow edema. If this represents the earliest stage of Charcot arthropathy, it is classified in the Eichenholtz system as:

Explanation

Eichenholtz Stage 0 represents the pre-radiographic stage of Charcot arthropathy, characterized by clinical signs of inflammation and MRI changes, but normal plain radiographs. Stage 1 is fragmentation, Stage 2 is coalescence, and Stage 3 is consolidation.

Question 84

In an anteroposterior compression type II (APC-II) pelvic ring injury, the pubic symphysis is widened by more than 2.5 cm. Which posterior ligamentous structures remain intact to provide rotational stability?

Explanation

An APC-II injury involves disruption of the pubic symphysis, anterior sacroiliac, sacrotuberous, and sacrospinous ligaments. The posterior sacroiliac ligaments remain intact, preventing vertical translation.

Question 85

A 45-year-old manual laborer presents with advanced Scaphoid Nonunion Advanced Collapse (SNAC) stage III wrist arthritis. The radiocarpal and midcarpal joints are arthritic, but the radiolunate articulation is spared. Which salvage procedure is most appropriate?

Explanation

In SNAC stage III, the capitate is involved in the arthritic process, making a proximal row carpectomy (PRC) contraindicated. Scaphoid excision and a four-corner fusion spares the preserved radiolunate joint and maintains partial wrist motion.

Question 86

A 12-year-old obese boy presents with acute-on-chronic left knee pain and an inability to bear weight. He is diagnosed with an unstable slipped capital femoral epiphysis (SCFE). Which of the following interventions carries the highest risk of iatrogenic avascular necrosis (AVN)?

Explanation

Forceful closed reduction of an unstable SCFE severely compromises the already tenuous epiphyseal blood supply, drastically increasing the risk of avascular necrosis. Current recommendations favor either in situ pinning or open reduction using a surgical hip dislocation approach to meticulously protect the retinacular vessels.

Question 87

A 35-year-old man sustains a high-energy Schatzker IV tibial plateau fracture with a large posteromedial shear fragment. Which of the following surgical approaches is most appropriate for direct visualization and buttress plating of this specific fragment?

Explanation

The posteromedial approach uses the interval between the medial head of the gastrocnemius (retracted laterally) and the pes anserinus (retracted medially). This allows direct, orthogonal access to the posteromedial shear fragment for optimal application of an anti-glide or buttress plate.

Question 88

A 16-year-old girl presents with a destructive diaphyseal lesion of the femur. Radiographs reveal a large soft tissue mass and an "onion skin" periosteal reaction. Histological examination shows sheets of small round blue cells. Which of the following chromosomal translocations is most characteristic of this tumor?

Explanation

This patient has Ewing sarcoma, a malignant bone tumor classically presenting with an "onion skin" periosteal reaction and sheets of small round blue cells on histology. It is most strongly associated with the t(11;22) chromosomal translocation, which produces the characteristic EWS-FLI1 fusion protein.

Orthopedic Prometric Exam Preparation MCQs - Part 1

Orthopedic Prometric Exam Preparation MCQs - Part 20

Orthopedic Prometric Exam Preparation MCQs - Part 20

Chapter Index