Question 1

A 5-year-old girl is brought to the emergency department because of fever and inability to walk. Her temperature is 100.5° F. She has pain with rotation of the hip. However, if the movement is done slowly, the hip can be rotated internally and externally 45°. Her white blood cell count is 13,000 (upper normal is 12,500 for her age). Her erythrocyte sedimentation rate is 30. Radiographs of the pelvis and hip are normal. You recommend:

Explanation

The scenario described above is most consistent with transient synovitis of the hip. Because range of motion is tolerated when performed slowly; it is compatible with a diagnosis of transient synovitis of the hip more than infection. Rest, with or without anti-inflammatory medicine, should produce a dramatic improvement by the next day.

Question 2

Which of the following factors is least likely to predispose a patient to patellar instability:

Explanation

Genu varum does not predispose a patient to patellar instability. However, genu valgum, as well as all of the other factors listed above, may predispose a patient to this condition.

Question 3

A 15-year-old girl twists her knee while skiing. She is diagnosed with a patellar dislocation. She has had no prior episodes. Radiographs show the dislocation but no other findings. After reducing the dislocation, you recommend:

Explanation

Acute traumatic patellofemoral dislocations are best treated by brief immobilization followed by early rehabilitation. Surgery is reserved for patients with multiple recurrences that cause significant disability.

Question 4

Which of the following is related to the etiology of Ewingâ s sarcoma:

Explanation

Ewing s sarcoma belongs to the family of round cell sarcomas. A translocation t(11:22)(q24q12) has been discovered in Ewing ssarcoma. This translocation results in a novel protein, EWS-FL11, that causes rapid growth of cells arising from the neural crest.

Question 5

A 5-year-old girl is brought to your office because of a mass in the back of her right knee. The family has noticed the mass for the past 8 months, and they also tell you that it varies in size with activity. The mass is painless and is located on the medial side of the popliteal fossa. It measures 2 cm to 4 cm and is discrete, firm, and nontender. Examinations of her knee and gait are unremarkable otherwise. You recommend:

Explanation

The patient history and physical examination are consistent with a benign popliteal cyst. This type of cyst is usually unassociated with any intra- articular pathology in children. The cyst resolves on its own with time. Further study or biopsy would be indicated only if the mass were progressively enlarging, tender, or located in an atypical area.

Question 6

A 20-month-old toddler is brought in because of bowed legs. You note moderate-to-severe genu varum and thigh-foot angles of 35° inward. The child is otherwise healthy, and height and weight are near the 50th percentiles. Radiographs demonstrate tibial metaphyseal-diaphyseal angles of 8° on the right and 9° on the left. Femoral metaphyseal-diaphyseal angles are the same. You recommend:

Explanation

This child has physiologic genu varum. Only if the metaphyseal-diaphyseal angles were greater than 11° would additional followup be indicated, with possible bracing. Blood tests would be indicated if the bone quality showed evidence of Rickets or if the child was below the 10th percentile in height.

Question 7

Which of the following is the most common complication after a posttraumatic distal radial growth arrest:

Explanation

The most common complication after a posttraumatic distal radial growth arrest is positive ulnar variance (overgrowth). Other complications may include decreased distal radial articular angle, triradiate fibrocartilage tear, or distal radioulnar joint instability, but they are less common. Increased radial articular angle and negative ulnar variance rarely develop after these injuries.

Question 8

Patients with which one of the following curve types associated with idiopathic scoliosis are at increased risk of shortness of breath:

Explanation

Idiopathic scoliosis is associated with measurable decreases in pulmonary function in thoracic curves larger than 60° to 70°, but a clinically significant increase in risk of shortness of breath has been shown only in thoracic curves larger then 80°.

Question 9

Which of the following patients with infantile idiopathic scoliosis can be observed without a magnetic resonance image (MRI):

Explanation

Patients with idiopathic infantile scoliosis have a 22% incidence of abnormalities that can be viewed on MRI. Syrinx and Chiari malformation are the most common abnormalities, with a similar rate as that found in patients with juvenile idiopathic scoliosis. The left thoracic curve pattern is most commonly seen in infantile patients, but a right thoracic curve is not protective. Age, freedom from pain, or a normal neurologic examination are also not protective. Magnetic resonance imaging is recommended for all infantile curves larger than 20°.

Question 10

Which of the following features differentiates a grade 2 open fracture from a grade 1 open fracture:

Explanation

A grade 2 open fracture is distinguished from a grade 1 open fracture by a laceration larger than 1 cm. Grade 3 open fractures are characterized by massive soft tissue damage, circulatory compromise, severe contamination, or marked instability. Grade 3A open fracture characteristics include extensive soft tissue lacerations but adequate skin to cover the bone. Grade 3B fractures show extensive soft tissue loss. Grade 3C open fractures demonstrate arterial injury and require repair.

Question 11

Which of the following features differentiates a grade 3B open fracture from a grade 3C open fracture:

Explanation

Grade 3 injuries all have massive soft tissue damage. Grade 3C fractures have vascular injury requiring repair, whereas grade 3B fractures do not have vascular injury or do not require repair. An example of the latter is a severe open fracture of the distal tibia with laceration of the dorsalis pedis artery and a foot that is well perfused through its collaterals.

Question 12

Which rating best describes a childs hip affected with Perthesâ disease that has healed with aspherical incongruity:

Explanation

The C atterall and Herring classifications are used during the evolution of Perthesâ disease to guide treatment; they are used during the fragmentation stage. It is impossible to know what the C atterall or Herring class was after healing has occurred. The Stulberg classification gives prognosis after healing. Stulberg 4 is aspherical but congruous. Stulberg 5 is aspherical and incongruous. Patients classified with Stulberg 5 hips typically have degenerative joint disease in early adulthood.

Question 13

Which of the following agents is used to reverse the effects of midazolam:

Explanation

Flumazenil (reversed) is used to reverse the effects of benzodiazepines. Flumazenil has a shorter duration of action than benzodiazepines, so it may need to be readministered. Flumazenil can also precipitate seizures.

Question 14

A 6-year-old boy is receiving pharmacologic agents to assist in the reduction of a forearm fracture. Which of the following conditions is not necessary for him to be in â conscious sedationâ :

Explanation

Under conscious sedation, a child must be able to open eyes to command, maintain a patent airway and reflexes, and have stable vital signs. However, consciousness is medically depressed by the drugs.

Question 15

A mutation in type II collagen is responsible for all of the following conditions except:

Explanation

Type II collagen is largely found in hyaline cartilage. All of the dysplasias, with the exception of achondroplasia, have significant abnormalities of articular cartilage. Achondroplasia results from a defect in fibroblast growth factor receptor protein.

Question 16

An adult man with hemophilia A has just announced the birth of his first son. His wife does not have the disease. What is the chance that the newborn has the disorder:

Explanation

Hemophilia A is an X-linked disorder. Therefore, there is no father-son transmission. The chance that the newborn is affected equals that of the general population, which is less than 1%.

Question 17

Which of the following conditions is least commonly seen in patients with congenital dislocation of the patella:

Explanation

Congenital dislocation of the patella is present from birth and diagnosed in childhood. It is not reducible with the knee in extension. Essential elements include contracture of the iliotibial band, vastus lateralis, hypoplasia of the vastus medialis, lateral insertion of the patellar tendon, decreased size of the patella, flexion contracture and valgus alignment of the knee, and hypoplasia of the patellar sulcus. Operative treatment is usually successful, and the success rate is increased with early surgery.

Question 18

The surgical reconstruction of a congenitally dislocated patella includes all of the following elements except:

Explanation

The surgical reconstruction of a congenitally dislocated patella includes lengthening or release of the lateral capsule, lengthening or release of the iliotibial band, lengthening or release of the biceps femoris muscle, distal advancement or imbrication of the patellar tendon, and sometimes a rectus femoris lengthening. Semitendinosus transfer to the patella may also be added. The lateral insertion of the patellar tendon may be transferred medially.

Question 19

Which of the following radiographic parameters is most appropriately used to assess the status of the hip in a growing child with cerebral palsy:

Explanation

The migration index (of Reimer) is the percentage of the femoral head outside of the acetabulum. This radiographic parameter tracks the progress of the hip in patients with cerebral palsy because the femoral head may gradually migrate out. The other parameters refer to radiographic assessments of other hip disorders: The Stulberg rating is used in patients with healed Perthesâ disorder. The alpha and beta angles of Graf provide ultrasonic assessment of patients with developmental hip dysplasia. Klein s line is used in early detection of slipped capital femoral epiphysis. The Hilgenreiner-epiphyseal angle is used in developmental coxa vara.

Question 20

What is the primary force applied to the spine during a C hance (seatbelt) fracture:

Explanation

The primary force applied to the spine during a C hance fracture is distraction. The body is flexed forward around an axis in front of the body (often a seatbelt), but the spine is subject to distraction because it is posterior to this axis. This motion results in a characteristic distraction of bony or ligamentous elements with minimal crush.

Question 21

During reconstruction of the medial patellofemoral ligament (MPFL), an error in femoral tunnel placement can lead to altered graft kinematics. If the femoral tunnel is placed too anteriorly, which of the following is the most likely clinical consequence?

Explanation

Schöttle's point identifies the anatomic femoral attachment of the MPFL. If the femoral tunnel is placed too anterior to the true origin, the graft will become inappropriately tight in flexion, potentially limiting range of motion and increasing patellofemoral pressures.

Question 22

A 14-year-old boy presents with a completely displaced tibial eminence (spine) fracture (Meyers and McKeever Type III) after a bicycle accident. What is the most appropriate management?

Explanation

Type III tibial eminence fractures are completely displaced and often have the anterior horn of the medial meniscus interposed, blocking closed reduction. Arthroscopic or open reduction and internal fixation is indicated to restore ACL tension and joint congruity.

Question 23

A 16-year-old female presents with recurrent lateral patellar instability. Imaging reveals a tibial tubercle-trochlear groove (TT-TG) distance of 22 mm and a normal Patellar Height Ratio. What is the most appropriate surgical intervention?

Explanation

A TT-TG distance >20 mm is a well-established indication for a tibial tubercle medialization osteotomy. Concomitant MPFL reconstruction is typically performed to restore the primary soft tissue restraint to lateral patellar translation.

Question 24

A 12-year-old overweight boy presents with sudden onset of severe groin pain and inability to bear weight on his right leg after a minor fall. Radiographs demonstrate a displaced capital femoral epiphysis. He had 3 weeks of mild antecedent thigh aching. Which of the following best characterizes his condition and associated risk?

Explanation

The inability to bear weight makes this an unstable slipped capital femoral epiphysis (SCFE) according to the Loder classification. Unstable SCFE has a significantly higher risk of avascular necrosis (AVN), historically up to 47%, compared to stable SCFE.

Question 25

In the evaluation of a pediatric patient with an irritable hip, which of the following is NOT one of the original Kocher criteria used to differentiate septic arthritis from transient synovitis?

Explanation

The original four Kocher criteria are non-weight-bearing, ESR >40, fever >38.5°C, and WBC >12,000. CRP >20 mg/L was later identified as an excellent independent predictor, but it was not part of the original Kocher criteria.

Question 26

A 9-year-old girl sustains a twisting injury to her knee. She complains of a snapping sensation on the lateral side of the knee. MRI demonstrates a discoid lateral meniscus with normal peripheral attachments. What is the most appropriate treatment if she is symptomatic?

Explanation

Symptomatic incomplete or complete discoid menisci with intact peripheral attachments are treated with arthroscopic saucerization to create a stable, more anatomically shaped meniscus. Peripheral repair is added only if a peripheral tear or instability (like the Wrisberg variant) is present.

Question 27

The medial patellofemoral ligament (MPFL) is the primary soft-tissue restraint to lateral patellar translation at which of the following knee flexion angles?

Explanation

The MPFL provides approximately 50% to 60% of the restraining force against lateral patellar displacement in early knee flexion (0 to 30 degrees). Beyond 30 degrees, the patella engages the trochlea, and the bony architecture becomes the primary stabilizer.

Question 28

A 7-year-old boy is diagnosed with Legg-Calvé-Perthes disease. According to the Herring lateral pillar classification, which radiographic finding defines a Group C hip?

Explanation

In the Herring lateral pillar classification, Group C is defined by the maintenance of less than 50% of the original lateral pillar height. This group carries the poorest prognosis for subsequent hip deformity and osteoarthritis.

Question 29

Which radiographic sign is pathognomonic for severe trochlear dysplasia and is characterized by the outline of the trochlear floor crossing the anterior contour of the lateral femoral condyle on a strict lateral radiograph?

Explanation

The crossing sign represents the trochlear groove becoming flush with the lateral femoral condyle, indicating a flat trochlea. It is the fundamental radiographic feature of trochlear dysplasia described by Dejour.

Question 30

A 10-year-old boy presents with anterior knee pain and a high-riding patella after forcefully jumping during a basketball game. Radiographs show a small bony fragment distal to the inferior pole of the patella. What is the most likely diagnosis?

Explanation

A patellar sleeve fracture is a chondrous or osteochondrous avulsion of the inferior pole of the patella seen in skeletally immature patients. A high-riding patella (patella alta) distinguishes it from Sinding-Larsen-Johansson syndrome, which is an overuse apophysitis without disruption of the extensor mechanism.

Question 31

A 12-year-old female gymnast presents with recurrent knee pain. Radiographs reveal a classic osteochondritis dissecans (OCD) lesion. Which of the following is the most common anatomical location for this lesion in the knee?

Explanation

The classic and most common location for an osteochondritis dissecans (OCD) lesion of the knee is the lateral aspect of the medial femoral condyle. This accounts for approximately 70% of all knee OCD lesions.

Question 32

During evaluation of a newborn, the orthopedic surgeon notes bilateral hyperextended knees. The diagnosis of congenital dislocation of the knee (CDK) is made. The infant also has positive Ortolani signs bilaterally. What is the most appropriate management sequence?

Explanation

In patients with congenital dislocation of the knee and concomitant developmental dysplasia of the hip (DDH), the knee deformity must be addressed first. Correcting the knee allows the necessary flexion required to safely treat the hips with a Pavlik harness.

Question 33

A 14-year-old female basketball player tears her anterior cruciate ligament (ACL). She has wide open physes. Which surgical technique carries the highest risk of causing a growth arrest with subsequent angular deformity or limb length discrepancy?

Explanation

Using a bone plug across an open physis significantly increases the risk of premature physeal closure. Soft-tissue grafts or completely physeal-sparing techniques are preferred in patients with significant remaining growth to avoid growth arrest.

Question 34

A 3-year-old boy refuses to bear weight on his right leg. His temperature is 38.8°C (101.8°F), ESR is 55 mm/hr, WBC is 14,000/mm3, and plain radiographs of the right hip are normal. Joint aspiration yields purulent fluid. What is the most critical immediate intervention?

Explanation

Septic arthritis of the hip in a pediatric patient is a surgical emergency. Urgent open or arthroscopic irrigation and debridement is required to decompress the joint, remove purulent material, and prevent avascular necrosis and cartilage destruction.

Question 35

Which of the following physical examination findings is most specific for identifying a torn anterior cruciate ligament in a pediatric or adolescent patient?

Explanation

While the Lachman test is highly sensitive, the pivot shift test is the most specific physical examination finding for an ACL tear. It dynamically reproduces the rotatory instability caused by the absent ligament.

Question 36

A 6-year-old child presents with a painless limp. Examination reveals limited abduction and internal rotation of the hip. Radiographs show increased radiodensity and fragmentation of the capital femoral epiphysis. What is the primary goal of treatment for this condition?

Explanation

The diagnosis is Legg-Calvé-Perthes disease. The primary goal of treatment is containment of the femoral head within the acetabulum during the fragmentation and reossification phases to ensure it heals spherically and to prevent late osteoarthritis.

Question 37

A 9-year-old boy sustains a complete anterior cruciate ligament (ACL) tear. He has wide-open physes and significant skeletal growth remaining. Which of the following surgical techniques minimizes the risk of growth arrest?

Explanation

In prepubescent children with significant growth remaining (Tanner stages 1 and 2), physeal-sparing ACL reconstruction techniques, such as the ITB extra-articular reconstruction or all-epiphyseal techniques, minimize the risk of physeal arrest. Transphyseal techniques carry a higher risk of growth disturbance in this age group.

Question 38

An 11-year-old male presents with vague knee pain. Radiographs reveal an osteochondritis dissecans (OCD) lesion on the lateral aspect of the medial femoral condyle. MRI shows no high T2 signal behind the lesion and intact overlying cartilage. What is the most appropriate initial management?

Explanation

Stable OCD lesions in skeletally immature patients (juvenile OCD) typically heal with nonoperative management, including activity modification and restricted weight-bearing. Surgical intervention is reserved for unstable lesions or failure of conservative treatment after 3 to 6 months.

Question 39

A 12-year-old obese boy presents to the emergency department unable to bear weight on his right leg after a minor fall. Radiographs demonstrate a severe right slipped capital femoral epiphysis (SCFE). Which of the following complications is he at the highest risk for developing compared to a patient who can bear weight?

Explanation

The inability to bear weight defines an unstable SCFE, which carries a significantly higher risk of avascular necrosis (up to 50%) compared to a stable SCFE. Urgent or semi-urgent in-situ pinning is required.

Question 40

In patients presenting with a unilateral slipped capital femoral epiphysis (SCFE), which of the following is the strongest indication for prophylactic pinning of the contralateral hip?

Explanation

Patients with endocrine disorders (e.g., hypothyroidism, renal osteodystrophy) or undergoing radiation therapy have a very high risk of bilateral SCFE. Prophylactic pinning of the contralateral hip is strongly recommended in these populations regardless of age.

Question 41

A 10-year-old boy presents with a swollen knee after jumping. He is unable to perform a straight leg raise. Radiographs reveal a high-riding patella and a small fleck of bone at the inferior pole of the patella. What is the most appropriate management?

Explanation

This presentation is classic for a patellar sleeve fracture, representing a significant avulsion of the extensor mechanism in children. Because the cartilaginous component is much larger than the radiographic bony fleck, operative repair is required to restore the extensor mechanism.

Question 42

A 6-week-old infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). What is the risk of excessive hyperflexion of the hips while in the harness?

Explanation

Excessive hyperflexion (>120 degrees) in a Pavlik harness risks femoral nerve palsy. Excessive abduction increases the risk of avascular necrosis of the femoral head.

Question 43

A 4-year-old boy presents with a 2-day history of right hip pain and a limp. He is afebrile (37.2 degrees C), WBC is 10,500/mm3, ESR is 15 mm/hr, and he can bear weight with a limp. He refuses internal rotation of the hip. What is the most appropriate next step in management?

Explanation

The patient has 0 out of 4 Kocher criteria (fever >38.5 C, non-weight bearing, ESR >40, WBC >12,000), making septic arthritis highly unlikely. The most likely diagnosis is transient synovitis, which is treated supportively with NSAIDs and observation.

Question 44

In evaluating a 7-year-old child with Legg-Calve-Perthes disease, the Herring Lateral Pillar Classification is used to determine prognosis. Which radiographic view and stage of the disease are most appropriate for applying this classification?

Explanation

The Herring Lateral Pillar Classification assesses the height of the lateral pillar of the femoral head and is best applied on an AP radiograph during the fragmentation stage of the disease. This stage provides the most accurate prognostic information regarding final femoral head sphericity.

Question 45

A 13-year-old boy complains of recurrent ankle sprains and lateral foot pain. Examination reveals rigid flatfeet and pain with subtalar motion. Oblique radiographs of the foot demonstrate an "anteater nose" sign. What is the most likely diagnosis?

Explanation

The "anteater nose" sign on an oblique radiograph of the foot represents an elongated anterior process of the calcaneus, diagnostic of a calcaneonavicular coalition. Talocalcaneal coalitions are typically identified by the "C-sign" on a lateral radiograph.

Question 46

A 3-year-old girl is evaluated for worsening bilateral genu varum. Standing radiographs show a sharp varus angulation at the proximal medial tibial metaphysis with beaking and an epiphyseal-metaphyseal angle of 22 degrees. What is the most appropriate initial treatment?

Explanation

The patient has infantile Blount disease, indicated by progressive varus and an epiphyseal-metaphyseal (Drennan) angle >16 degrees. For children under age 3-4 with early-stage infantile Blount disease, KAFOs are the recommended initial treatment.

Question 47

An 18-month-old child presents with anterolateral bowing of the left tibia. Radiographs show medullary sclerosis and a narrow, dysplastic tibial diaphysis. What is the most commonly associated systemic condition?

Explanation

Anterolateral bowing of the tibia is the hallmark precursor to congenital pseudarthrosis of the tibia. Over 50% of these cases are associated with Neurofibromatosis type 1 (NF1).

Question 48

During the Ponseti casting technique for the treatment of idiopathic clubfoot, what is the correct order of deformity correction?

Explanation

The acronym CAVE dictates the sequence of clubfoot correction in the Ponseti method: Cavus (corrected by supinating the forefoot to align with the hindfoot), Adductus, Varus, and finally Equinus (often requiring a percutaneous Achilles tenotomy).

Question 49

A 6-year-old Asian female presents with a painless "snapping" and "clunking" in her right knee during terminal extension. She denies swelling or mechanical locking. Radiographs show mild widening of the lateral joint space. What is the most appropriate management?

Explanation

The presentation is classic for a discoid lateral meniscus. In an asymptomatic or completely painless snapping knee without locking or effusion, the recommended management is observation and reassurance.

Question 50

A 10-year-old girl falls off her bicycle and sustains a hyperextension injury to her knee. Radiographs reveal a completely displaced, non-comminuted fracture of the tibial spine (Meyers and McKeever Type III). What is the optimal treatment?

Explanation

Meyers and McKeever Type III fractures are completely displaced and often have interposed tissue preventing closed reduction. They require arthroscopic or open reduction and internal fixation using sutures, wires, or screws.

Question 51

During medial patellofemoral ligament (MPFL) reconstruction, identifying the correct femoral attachment is crucial for restoring normal kinematics. Which of the following best describes the anatomical location of the MPFL femoral origin?

Explanation

The MPFL femoral origin is located between the medial epicondyle and the adductor tubercle, slightly proximal and posterior to the medial epicondyle. This location corresponds to Schottle's point on lateral radiographs. Improper tunnel placement here is the most common cause of MPFL graft failure.

Question 52

A 4-month-old infant with developmental dysplasia of the hip (DDH) is being treated with a Pavlik harness. During a follow-up visit, you notice the infant has decreased active knee extension on the affected side. Which of the following is the most appropriate next step?

Explanation

Decreased active knee extension indicates a femoral nerve palsy, a known complication of excessive hyperflexion in a Pavlik harness. The harness should be discontinued or adjusted to decrease hip flexion. Observation is typically sufficient as it generally resolves spontaneously.

Question 53

A 12-year-old obese boy presents with acute-on-chronic left groin pain and inability to bear weight. Radiographs show a severe slipped capital femoral epiphysis (SCFE). Which of the following factors most significantly increases his risk of avascular necrosis (AVN)?

Explanation

The inability to bear weight defines an unstable SCFE, which carries a much higher risk of avascular necrosis (up to 50%) compared to a stable SCFE. Severity of the slip is less predictive of AVN than the stability of the physis.

Question 54

In the evaluation of a 6-year-old boy with Legg-Calve-Perthes disease, which of the following radiographic classifications is most prognostic for long-term hip joint congruency?

Explanation

The lateral pillar (Herring) classification is considered the most reliable prognostic indicator for long-term outcomes in Perthes disease. It assesses the height of the lateral pillar of the capital femoral epiphysis during the fragmentation phase. The Stulberg classification assesses the final outcome at skeletal maturity, not initial prognosis.

Question 55

A 9-year-old girl (Tanner stage 1) sustains a midsubstance anterior cruciate ligament (ACL) tear. Her parents opt for surgical reconstruction. Which of the following techniques is most appropriate to minimize the risk of growth arrest?

Explanation

In prepubescent children with significant growth remaining (Tanner stage 1), an all-epiphyseal or physeal-sparing extra-articular (e.g., IT band) reconstruction is recommended. Transphyseal techniques risk growth arrest and angular deformity in this age group.

Question 56

A 14-year-old boy presents with vague knee pain and occasional catching. Radiographs reveal an osteochondritis dissecans (OCD) lesion. What is the most common anatomical location for this lesion in the knee?

Explanation

The classic and most common location for an OCD lesion in the knee is the lateral aspect of the medial femoral condyle. This accounts for approximately 70-80% of knee OCD lesions.

Question 57

A 4-year-old boy refuses to bear weight on his right leg. He has a temperature of 38.5 degrees C, ESR of 45 mm/hr, WBC of 13,000/mm3, and refuses to move his hip. According to the Kocher criteria, what is the approximate probability he has septic arthritis rather than transient synovitis?

Explanation

This patient has 4 Kocher criteria: non-weight-bearing, temperature >38.5 C, ESR >40, and WBC >12,000. The presence of 4 criteria predicts a 99% probability of septic arthritis, distinguishing it from transient synovitis.

Question 58

A 10-year-old boy falls off his bicycle and presents with a swollen, painful knee. Radiographs reveal a Meyers and McKeever Type III tibial eminence fracture. What is the most appropriate management?

Explanation

A Type III tibial eminence fracture involves complete displacement of the avulsed fragment. It typically requires arthroscopic or open reduction and internal fixation to restore ACL tension and prevent mechanical block to extension.

Question 59

A 6-year-old girl presents with a painless snapping sensation on the lateral aspect of her knee during extension. Which of the following MRI findings is most likely associated with her condition?

Explanation

The clinical presentation is classic for a discoid lateral meniscus, which presents as a snapping knee in children. On MRI, it is diagnosed when three or more consecutive sagittal slices show continuity of the anterior and posterior horns (bowtie sign).

Question 60

A 10-year-old boy presents to the emergency department after a forceful jumping injury. He has a massive knee effusion, a palpable defect at the inferior pole of the patella, and cannot perform a straight leg raise. Lateral radiographs show a high-riding patella with a tiny bony fleck distally. What is the most likely diagnosis?

Explanation

The presentation is classic for a patellar sleeve fracture, an avulsion of the unossified distal patellar cartilage along with a small bony fragment. It disrupts the extensor mechanism and requires surgical repair.

Question 61

A newborn is evaluated for a shortened lower extremity. Radiographs show a shortened femur with a hypoplastic proximal segment and an absent fibula. This presentation is most consistent with Proximal Focal Femoral Deficiency (PFFD). Which of the following conditions is most commonly associated with PFFD?

Explanation

Fibular hemimelia is the most common associated anomaly in patients with Proximal Focal Femoral Deficiency (PFFD), occurring in 50% to 80% of cases. Cruciate ligament deficiency in the knee is also frequently seen.

Question 62

Which of the following describes the fundamental pathophysiology of Osgood-Schlatter disease in a 13-year-old athlete?

Explanation

Osgood-Schlatter disease is a traction apophysitis of the tibial tubercle. It occurs due to repetitive microtrauma from the pull of the patellar tendon on the unossified or partially ossified tibial apophysis.

Question 63

A 14-year-old boy sustains an ankle injury while sliding into a base. Radiographs show a Salter-Harris III fracture of the anterolateral distal tibial epiphysis. What ligament avulsion is responsible for this fracture pattern?

Explanation

A juvenile Tillaux fracture is a Salter-Harris III fracture of the anterolateral tibial epiphysis. It is caused by an avulsion force from the anterior inferior tibiofibular ligament (AITFL) during external rotation.

Question 64

A triplane fracture of the distal tibia in a pediatric patient consists of fracture lines occurring in three distinct planes. Which of the following accurately describes the orientation of these fracture lines?

Explanation

A triplane fracture typically appears as a Salter-Harris III on AP views and a Salter-Harris II on lateral views. The fracture planes are sagittal in the epiphysis, axial (horizontal) through the physis, and coronal in the metaphysis.

Question 65

A 4-year-old boy presents with a 2-day history of right hip pain, a temperature of 38.8°C (101.8°F), an inability to bear weight, a WBC count of 14,000/mm3, and an ESR of 50 mm/hr. What is the most appropriate next step in management?

Explanation

The patient has 4 out of 4 Kocher criteria, yielding a 99% probability of septic arthritis. Immediate joint aspiration is the gold standard for definitive diagnosis before initiating antibiotic therapy.

Question 66

During medial patellofemoral ligament (MPFL) reconstruction, identifying the correct femoral attachment point is critical. Which of the following best describes the anatomic location of the femoral footprint of the MPFL?

Explanation

The MPFL femoral insertion (Schöttle point) is located in the saddle-shaped depression between the medial epicondyle and the adductor tubercle. Anatomical placement is crucial to restore normal patellofemoral kinematics.

Question 67

A 16-year-old boy sustains a first-time lateral patellar dislocation. Radiographs reveal a 15-mm osteochondral loose body within the joint. MRI confirms the fragment originated from the lateral femoral condyle. What is the recommended treatment?

Explanation

While first-time patellar dislocations are often treated non-operatively, the presence of a large, fixable osteochondral loose body is an absolute indication for surgery. Fixation of the fragment preserves joint congruity and function.

Question 68

An 8-year-old boy (Tanner stage 1) sustains a complete mid-substance anterior cruciate ligament (ACL) tear. Which of the following surgical techniques is most appropriate to minimize the risk of growth arrest?

Explanation

In prepubescent children (Tanner stage 1) with significant remaining growth, an entirely physeal-sparing extra-articular reconstruction (e.g., modified Micheli-Kocher technique) is recommended. This avoids drilling across open physes, minimizing the risk of growth arrest or angular deformity.

Question 69

A 12-year-old obese boy presents with an acute exacerbation of chronic right groin pain and an inability to bear weight. Radiographs show a severe slipped capital femoral epiphysis (SCFE). Which of the following intraoperative maneuvers is most strongly associated with the development of avascular necrosis (AVN)?

Explanation

Forceful closed reduction of a SCFE compromises the delicate retinacular vessels, significantly increasing the risk of avascular necrosis. Current gold-standard management involves gentle positioning and in situ pinning.

Question 70

A 22-year-old woman presents with recurrent lateral patellar instability. A CT scan is obtained to evaluate her tibial tubercle-trochlear groove (TT-TG) distance. Above what TT-TG threshold is a tibial tubercle medialization osteotomy typically indicated?

Explanation

A TT-TG distance greater than 20 mm is widely considered abnormal and is a standard indication for medializing the tibial tubercle (e.g., Fulkerson osteotomy). Normal TT-TG distance is generally less than 15 mm.

Question 71

A 6-year-old girl presents with a painless, snapping sensation in her lateral knee during flexion and extension. MRI confirms an incomplete lateral discoid meniscus without a tear. What is the most appropriate management?

Explanation

Asymptomatic or mildly symptomatic (painless snapping) discoid menisci without tears should be managed non-operatively with observation. Surgical intervention (saucerization) is reserved for torn or persistently painful discoid menisci.

Question 72

In Legg-Calvé-Perthes disease, the Herring lateral pillar classification is used to predict long-term outcomes. During which phase of the disease should the radiographs be evaluated to determine the lateral pillar grade?

Explanation

The Herring lateral pillar classification is most accurately determined during the late fragmentation phase of Legg-Calvé-Perthes disease. This ensures the maximal extent of epiphyseal involvement is visible for prognostic accuracy.

Question 73

A 10-year-old boy falls off his bicycle and sustains a Type III (completely displaced) tibial eminence fracture. Which of the following structures is most likely at risk of being incarcerated under the fracture fragment, preventing closed reduction?

Explanation

In completely displaced (Type III) tibial eminence fractures, the anterior horn of the medial meniscus or the transverse intermeniscal ligament often becomes incarcerated beneath the fragment. This requires arthroscopic or open reduction to clear the block and achieve anatomic fixation.

Question 74

A 9-year-old boy presents with knee pain and swelling after forcefully jumping. He has a high-riding patella and an inability to actively extend the knee against gravity. Radiographs show a small, 2-mm bony fragment near the inferior pole of the patella. What is the most likely diagnosis?

Explanation

A patellar sleeve fracture is a pediatric injury involving the avulsion of a large cartilaginous cap from the patella, often with only a tiny osseous fleck visible on X-ray. It presents with an extensor lag and requires surgical repair to restore the extensor mechanism.

Question 75

An infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). The mother notes that the child has stopped actively extending the knee on the treated side. Which of the following harness positioning errors most likely caused this complication?

Explanation

Excessive hip flexion in a Pavlik harness (typically >120 degrees) can cause femoral nerve compression against the inguinal ligament, leading to quadriceps palsy and an inability to extend the knee. Excessive abduction leads to AVN.

Question 76

A 3-year-old girl presents with progressive bilateral bowlegs. Radiographs reveal varus deformity localized to the proximal tibia with a metaphyseal-diaphyseal angle (Drennan's angle) of 18 degrees. What does this finding indicate?

Explanation

A metaphyseal-diaphyseal angle greater than 16 degrees on an AP radiograph strongly indicates a high risk of progression to infantile Blount disease. Angles less than 11 degrees are typically consistent with physiologic bowing.

Question 77

When correcting a congenital idiopathic clubfoot using the Ponseti method, the acronym CAVE dictates the order of correction. What is the very first step in the manipulation and casting sequence?

Explanation

The first step in the Ponseti method is correcting the cavus deformity. This is achieved by elevating the first metatarsal to align the forefoot with the hindfoot, creating a stable fulcrum for subsequent abduction.

Question 78

A 13-year-old boy presents with left hip pain and an antalgic gait. During physical examination, as the affected hip is passively flexed, the thigh obligatorily rotates externally. This clinical finding is known as:

Explanation

The Drehmann sign describes the obligatory external rotation and abduction of the hip during passive flexion. It is a classic physical examination finding in slipped capital femoral epiphysis (SCFE).

Orthopedic Prometric MCQs - Chapter 3 Part 1

Orthopedic Prometric MCQs - Chapter 3 Part 5

Orthopedic Prometric MCQs - Chapter 3 Part 5

Chapter Index