Orthopedic Board Review MCQs 2026: Part 2 Practice

Question 1

A 65-year-old male presents with groin pain 5 years after a primary THA using a metal-on-polyethylene bearing with a large diameter titanium femoral head and a modular cobalt-chromium neck. Inflammatory markers are normal. Aspiration yields fluid with 300 WBCs/uL and 50% PMNs. MRI with MARS reveals a solid soft tissue mass and fluid collection. What is the most likely diagnosis, and what serum markers should be checked?

Explanation

Mechanically assisted crevice corrosion (MACC) at the head-neck or neck-stem junction (trunnionosis) is a recognized complication, especially with mixed metal combinations (e.g., Ti and CoCr) or large femoral heads. Checking serum Co and Cr levels helps in diagnosing trunnionosis in metal-on-polyethylene bearings, as the bearing itself does not produce metal ions. The local tissue reaction is an adverse local tissue reaction (ALTR) often characterized by solid or cystic masses.

Question 2

A 32-year-old female presents with a distal femur fracture following an MVC. CT reveals a coronal plane fracture of the lateral femoral condyle. What is the optimal surgical approach and standard fixation strategy for this specific fragment?

Explanation

A Hoffa fracture (coronal shear fracture) most commonly involves the lateral femoral condyle. The optimal approach is typically a direct lateral or Swashbuckler approach. While biomechanical studies have shown that posterior-to-anterior screws may be stiffer, anterior-to-posterior (A-P) directed lag screws placed perpendicular to the fracture line are the standard and most commonly used clinical fixation method due to ease of surgical access and avoidance of posterior neurovascular structures.

Question 3

A 28-year-old female presents with a lytic lesion in her distal femur abutting the joint. Biopsy confirms a Giant Cell Tumor of bone. She is treated with Denosumab prior to surgery. What is the mechanism of action of Denosumab, and what is the characteristic histological change seen after treatment?

Explanation

Denosumab is a monoclonal antibody that binds to RANKL, preventing it from interacting with RANK on osteoclasts and osteoclast-like giant cells. In Giant Cell Tumor of bone, it leads to a dramatic depletion of the multinucleated giant cells, leaving behind a fibrous stroma and resulting in dense woven bone formation and peripheral rimming.

Question 4

A 12-year-old boy with a BMI of 35 presents with left groin pain and an obligate external rotation of the hip with flexion. Radiographs show a severe left slipped capital femoral epiphysis (SCFE). When considering prophylactic pinning of the contralateral asymptomatic right hip, which of the following represents the strongest indication?

Explanation

Prophylactic pinning of the contralateral hip in SCFE is recommended in patients with a high risk of a future slip. Open triradiate cartilage is a strong radiographic marker of skeletal immaturity and is considered one of the most reliable predictors for a contralateral slip. A low modified Oxford bone age score (e.g., 16) also indicates immaturity, whereas a score of 20 indicates skeletal maturity.

Question 5

An 82-year-old male presents after a low-energy fall with neck pain. CT reveals a Type II odontoid fracture with 2 mm of posterior displacement. He is neurologically intact. What is the most appropriate management, considering his age and fracture characteristics?

Explanation

In the elderly population (>80 years), nonoperative management with a rigid cervical collar has been shown to have lower morbidity and mortality compared to surgery or halo vest immobilization for Type II odontoid fractures. While nonunion rates are high, a stable fibrous nonunion is typically well tolerated. Halo vests carry an unacceptably high risk of pulmonary complications and mortality in this age group.

Question 6

A 19-year-old female collegiate soccer player undergoes ACL reconstruction using a bone-patellar tendon-bone (BTB) autograft. Compared to hamstring autograft, which of the following is an expected long-term outcome associated with BTB autograft?

Explanation

Bone-patellar tendon-bone (BTB) autograft is associated with a significantly higher incidence of anterior knee pain and kneeling pain compared to hamstring autografts. BTB grafts typically have a lower or equivalent rate of graft rupture compared to hamstrings in young athletes and do not alter the risk of contralateral ACL rupture.

Question 7

During a primary posterior-stabilized total knee arthroplasty, after making the standard bone cuts, the trial components are inserted. The knee is tight in extension but balanced in flexion. Which of the following is the most appropriate next step?

Explanation

A knee that is tight in extension and balanced in flexion indicates an extension gap that is too small relative to the flexion gap. Resecting more distal femur increases the extension gap without affecting the flexion gap. Resecting more proximal tibia would increase both the flexion and extension gaps symmetrically.

Question 8

Which of the following Bone Morphogenetic Proteins (BMPs) is NOT correctly paired with its clinical application, carrier, or mechanism?

Explanation

rhBMP-2 (Infuse) is approved for use in acute, open tibial shaft fractures treated with an IM nail (using an absorbable collagen sponge carrier). rhBMP-7 (OP-1) was previously available under a humanitarian device exemption for recalcitrant tibial nonunions and revision posterolateral lumbar fusion, but it was not approved for acute open tibial fractures. Both BMPs act through serine/threonine kinase receptors and the SMAD intracellular signaling pathway.

Question 9

A 25-year-old male sustains a laceration to the volar aspect of his index finger at the level of the middle phalanx, just proximal to the DIP joint. Examination reveals an inability to flex the DIP joint, but PIP flexion against resistance is intact. In which flexor tendon zone did the injury occur, and what is the optimal surgical timing?

Explanation

The injury is located at the middle phalanx, distal to the FDS insertion, placing it in Zone I (which contains only the FDP tendon). A purely FDP laceration allows intact PIP flexion. The standard of care is a primary repair in the operating room within 7 to 14 days to prevent tendon retraction and optimize outcomes.

Question 10

A 45-year-old female is struck by a motor vehicle and sustains an anteroposterior compression (APC) type III pelvic ring injury. She remains hemodynamically unstable despite a pelvic binder and initial fluid resuscitation. What is the most appropriate next step in management?

Explanation

In a hemodynamically unstable patient with an APC pelvic ring injury who does not respond to initial mechanical stabilization (e.g., pelvic binder) and resuscitation, the source of bleeding is most likely the retroperitoneal venous plexus or arterial injury. Pre-peritoneal pelvic packing (PPP) and/or pelvic angiography with embolization are the appropriate next steps to control hemorrhage. Laparotomy is indicated for intra-abdominal bleeding, not primarily for pelvic retroperitoneal bleeding.

Question 11

A 6-month-old female presents with a neglected developmental dysplasia of the hip (DDH). Ultrasound and plain radiographs confirm a dislocated left hip. She has never received treatment. What is the most appropriate initial management?

Explanation

At 6 months of age, a Pavlik harness is generally less effective and carries a higher failure rate. The standard initial management for a 6-month-old with a dislocated hip is an examination under anesthesia, closed reduction, and spica casting. Open reduction is indicated if a concentric closed reduction cannot be achieved or if the child presents at an older age (e.g., typically >18 months).

Question 12

Articular cartilage is divided into four structural zones. Which zone is characterized by the highest concentration of proteoglycans, lowest concentration of water, and collagen fibers oriented perpendicular to the articular surface?

Explanation

The deep (radial) zone of articular cartilage contains collagen fibers that are oriented perpendicular to the articular surface, anchoring the cartilage to the tidemark. This zone possesses the highest concentration of proteoglycans and the lowest water content, optimizing it for compressive load resistance. The superficial zone has collagen parallel to the joint, highest water content, and lowest proteoglycan content.

Question 13

A 15-year-old male presents with distal femur pain and a sunburst periosteal reaction on radiographs. Biopsy confirms high-grade intramedullary osteosarcoma. Which of the following factors is the most important prognostic indicator for his long-term survival?

Explanation

The most important prognostic factor for long-term survival in patients with localized high-grade osteosarcoma is the histological response to neoadjuvant chemotherapy. A favorable response is classically defined as greater than 90% tumor necrosis at the time of surgical resection, which correlates with significantly improved survival.

Question 14

A 24-year-old football player sustains a hyperplantarflexion injury to his midfoot. Radiographs show a 3 mm diastasis between the base of the first and second metatarsals. He is diagnosed with a purely ligamentous Lisfranc injury. What is the currently recommended surgical treatment for this specific type of injury?

Explanation

For purely ligamentous Lisfranc injuries, level I evidence suggests that primary arthrodesis of the medial column (1st, 2nd, and 3rd TMT joints) results in better functional outcomes and a lower rate of hardware removal or reoperation compared to ORIF. Bony Lisfranc injuries, however, are typically treated with ORIF.

Question 15

A 60-year-old male presents with worsening clumsiness in his hands and a wide-based gait. Physical examination reveals positive Hoffman's sign and hyperreflexia. MRI shows multi-level cervical spondylotic myelopathy with anterior compression from C3 to C6 and preservation of cervical lordosis. What is the preferred surgical intervention?

Explanation

In patients with multi-level (typically ≥ 3 levels) cervical spondylotic myelopathy who have maintained cervical lordosis and lack significant instability, a posterior approach such as cervical laminoplasty is an excellent option. It avoids the morbidity of multi-level anterior surgery (dysphagia, pseudarthrosis) and prevents the progressive post-laminectomy kyphosis seen with laminectomy alone. It also preserves some cervical motion.

Question 16

A 40-year-old male presents with an acute Achilles tendon rupture. He is treated nonoperatively with an early functional rehabilitation protocol. Compared to surgical repair, what are the expected complication rates regarding re-rupture and wound complications?

Explanation

Recent high-quality randomized controlled trials have demonstrated that when an early functional rehabilitation protocol (early weight-bearing and active mobilization) is utilized, the re-rupture rates between nonoperative and operative treatment of acute Achilles tendon ruptures are statistically similar. Operative treatment carries a significantly higher risk of complications such as infection, skin necrosis, and sural nerve injury. Therefore, nonoperative management with functional rehab offers similar efficacy with a lower risk of wound complications.

Question 17

A 22-year-old male collegiate baseball pitcher complains of anterior shoulder pain during the late cocking phase of throwing. An MRI arthrogram reveals a SLAP tear. He undergoes arthroscopic SLAP repair. Which of the following is the most likely postoperative complication that could end his pitching career?

Explanation

In elite overhead throwing athletes (such as pitchers), arthroscopic SLAP repair has a low rate of return to pre-injury level of play. Postoperative stiffness, specifically a loss of maximum external rotation, is the most common reason for failure to return to pitching. Due to this high failure rate, many surgeons now prefer nonoperative management focusing on posterior capsular stretching or biceps tenodesis in this specific athletic population.

Question 18

A 26-year-old male presents with a proximal pole scaphoid fracture. The vascular supply to the scaphoid makes this region susceptible to avascular necrosis. Which vessel provides the primary blood supply to the proximal pole of the scaphoid?

Explanation

The major blood supply to the scaphoid (providing 70-80% of its perfusion) comes from the dorsal carpal branch of the radial artery, which enters the scaphoid at the dorsal ridge (distal half) and flows in a retrograde fashion to supply the proximal pole. This retrograde blood flow is the primary reason why proximal pole scaphoid fractures carry a high risk for avascular necrosis and nonunion.

Question 19

When considering bearing surfaces in total hip arthroplasty, which of the following combinations has the lowest volumetric wear rate in laboratory testing?

Explanation

Ceramic-on-ceramic bearing surfaces exhibit the lowest volumetric wear rates of any THA bearing combination. They are highly scratch-resistant and hydrophilic, which provides excellent boundary lubrication. However, their use is limited by concerns over component squeaking, catastrophic ceramic fracture, and technically demanding insertion.

Question 20

A 28-year-old male sustains a closed comminuted tibial shaft fracture. He develops severe pain out of proportion to his injury and pain with passive stretch of his hallux. Compartment pressure monitoring is obtained. Which of the following criteria is the most reliable threshold for diagnosing acute compartment syndrome and indicating the need for fasciotomy?

Explanation

The Delta P (Diastolic blood pressure minus compartment pressure) is the most reliable objective metric for diagnosing acute compartment syndrome. A Delta P of less than 30 mmHg indicates inadequate perfusion pressure to the muscular compartments and is a clear indication for fasciotomy. Absolute compartment pressures can lead to overdiagnosis and unnecessary fasciotomies, especially in hypotensive patients.

Question 21

A 65-year-old male presents with progressive clumsiness in his hands and a broad-based gait. Physical examination reveals a positive Hoffmann's sign bilaterally and hyperreflexia in the lower extremities. MRI of the cervical spine demonstrates multi-level spondylotic cord compression from C3 to C6. Sagittal alignment is neutral, and the patient denies any significant neck pain. What is the most appropriate surgical intervention?

Explanation

Cervical laminoplasty is ideal for multi-level compression in patients with neutral or lordotic alignment and absent/minimal mechanical neck pain. Laminectomy alone in adults has an unacceptably high rate of post-laminectomy kyphosis.

Question 22

A 12-year-old boy presents with thigh pain and swelling. Radiographs show a permeative diaphyseal lesion of the femur with an 'onion-skin' periosteal reaction. Biopsy confirms small, round, blue cells that stain positive for CD99. Which of the following chromosomal translocations is most characteristic of this pathology?

Explanation

Ewing sarcoma is characterized by the t(11;22)(q24;q12) translocation, leading to the EWS-FLI1 fusion protein. t(X;18) is seen in synovial sarcoma, and t(12;16) in myxoid liposarcoma.

Question 23

A 45-year-old female with a BMI of 35 presents with acute medial knee pain after a deep knee flexion maneuver. MRI confirms a complete radial tear at the medial meniscus posterior root footprint. What is the primary biomechanical consequence of this specific injury pattern if left untreated?

Explanation

A posterior root tear disrupts the meniscal hoop stresses, causing the meniscus to extrude. Biomechanically, this results in peak contact pressures identical to a complete meniscectomy, predisposing to rapid cartilage degradation.

Question 24

A 30-year-old male sustains a severe inversion injury to his ankle in an MVC. Radiographs and CT demonstrate a Hawkins III fracture of the talar neck.

Which of the following arteries, providing the predominant blood supply to the talar body, is most likely disrupted in this injury?

Explanation

The artery of the tarsal canal (a branch of the posterior tibial artery) provides the major blood supply to the talar body. A Hawkins III fracture (dislocation of subtalar and tibiotalar joints) confers a nearly 100% risk of avascular necrosis due to complete vascular disruption.

Question 25

According to the 2018 International Consensus Meeting (ICM) criteria, which of the following findings serves as a definitive 'major criterion' for the diagnosis of a periprosthetic joint infection (PJI)?

Explanation

Under the 2018 ICM criteria, the two major criteria for definitive PJI are a sinus tract communicating with the joint and two positive cultures identifying the same organism. All other options are considered minor criteria.

Question 26

A 13-year-old obese male presents with left hip pain and an obligatory external rotation of the hip during passive flexion. Slipped capital femoral epiphysis (SCFE) is confirmed. Prophylactic pinning of the asymptomatic contralateral hip is most strongly indicated if the patient has a concomitant diagnosis of:

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly recommended for patients with underlying endocrine or metabolic disorders (like hypothyroidism or renal osteodystrophy) due to a substantially higher risk of bilateral involvement.

Question 27

A 40-year-old male is brought to the trauma bay following a crush injury. He is hemodynamically unstable. Pelvic radiographs demonstrate an anteroposterior compression (APC) type III injury with a widely open symphysis pubis. Where is the optimal anatomical placement of a circumferential pelvic sheet or binder to reduce pelvic volume?

Explanation

A pelvic binder must be centered over the greater trochanters to generate the appropriate force vector to close an open-book pelvic ring injury effectively. Placement over the iliac crests is incorrect and can exacerbate the deformity.

Question 28

During a flexor tendon repair in Zone II of the hand, maintaining the integrity of the flexor tendon sheath and pulley system is crucial. Which two pulleys are considered the most critical to preserve in order to prevent bowstringing of the flexor tendons?

Explanation

The A2 (proximal phalanx) and A4 (middle phalanx) pulleys are the most biomechanically critical components of the flexor sheath. Loss of these pulleys leads to significant bowstringing and loss of active finger flexion.

Question 29

A 65-year-old male undergoes arthroscopic repair of a massive rotator cuff tear. Preoperative MRI demonstrated significant tendon retraction. Which of the following preoperative imaging findings is the strongest independent predictor of structural failure following repair?

Explanation

High grades of fatty infiltration (Goutallier stage 3 or 4) are irreversible and highly predictive of poor clinical outcomes and structural failure of the repaired rotator cuff tendon.

Question 30

A 25-year-old professional football player suffers a hyper-plantarflexion injury to his midfoot. Weight-bearing radiographs demonstrate widening between the first and second metatarsals.

Anatomically, the critical structure injured in this pattern (the Lisfranc ligament) connects which two bony structures?

Explanation

The primary Lisfranc ligament is an interosseous ligament that originates on the lateral aspect of the medial cuneiform and inserts on the medial base of the second metatarsal. There is no direct ligamentous connection between the bases of the 1st and 2nd metatarsals.

Question 31

Understanding the microanatomy of the physis is essential in pediatric orthopedics. In Slipped Capital Femoral Epiphysis (SCFE), the mechanical failure primarily occurs through which cellular zone of the physis?

Explanation

The hypertrophic zone is the weakest layer of the physis mechanically due to an increased matrix-to-cell ratio and loss of longitudinal septa. It is the zone where failure occurs in SCFE and typical Salter-Harris type I fractures.

Question 32

A 32-year-old female presents with a highly unstable, vertically oriented (Pauwels type III) femoral neck fracture following a fall from height. What is the most biomechanically advantageous construct for internal fixation of this specific fracture pattern to minimize shear forces?

Explanation

Pauwels type III fractures are highly vertical and subjected to massive shear forces. A fixed-angle construct (like a sliding hip screw) combined with an anti-rotation screw provides superior biomechanical stability compared to parallel cancellous screws.

Question 33

A surgeon utilizing the direct lateral (Hardinge) approach for a total hip arthroplasty splits the gluteus medius muscle. To avoid iatrogenic injury causing a postoperative Trendelenburg gait, the superior splitting of the gluteus medius must not extend beyond what distance proximal to the greater trochanter?

Explanation

The superior gluteal nerve innervates the gluteus medius and minimus. To prevent denervation during the direct lateral approach, the split should not extend beyond 3 to 5 cm proximal to the tip of the greater trochanter.

Question 34

An infant is diagnosed with idiopathic clubfoot (talipes equinovarus) and is set to undergo serial casting using the Ponseti method. What is the correct chronological sequence of deformity correction using this technique?

Explanation

The Ponseti method follows the CAVE sequence: Cavus is corrected first by supinating the forefoot, followed by Adductus and Varus by abducting the foot around the talar head, and finally Equinus with dorsiflexion and often a percutaneous Achilles tenotomy.

Question 35

A 55-year-old male presents with severe unremitting thigh pain. Radiographs demonstrate a destructive diaphyseal lesion with prominent endosteal scalloping and cortical breakthrough. Biopsy reveals a lobular architecture of atypical cartilaginous cells in a myxoid matrix. Which of the following is the standard treatment for a conventional grade II chondrosarcoma?

Explanation

Conventional chondrosarcoma is notoriously resistant to both chemotherapy and radiation. The mainstay of treatment for intermediate and high-grade (Grade II/III) chondrosarcoma is wide surgical resection.

Question 36

A 10-year-old restrained passenger in a high-speed MVC sustains a flexion-distraction injury (Chance fracture) of the L2 vertebra.

This specific spinal fracture pattern in pediatric patients has a high concomitant association with which of the following injuries?

Explanation

Chance fractures (flexion-distraction injuries) are commonly caused by lap-belt injuries in children. They carry a very high association (up to 50%) with intra-abdominal injuries, particularly hollow viscus perforations (e.g., small bowel).

Question 37

While most scapular fractures are treated non-operatively, surgical fixation of a scapular neck fracture is typically indicated when the glenopolar angle (GPA) falls below which of the following thresholds?

Explanation

A normal glenopolar angle is between 30 and 45 degrees. A severely decreased glenopolar angle of less than 20-22 degrees alters glenohumeral biomechanics significantly and is a standard indication for operative fixation.

Question 38

Intravenous Vancomycin is frequently used as prophylaxis or treatment in orthopedic surgery for MRSA infections. What is the specific cellular mechanism of action of this antibiotic?

Explanation

Vancomycin is a glycopeptide antibiotic that inhibits cell wall synthesis by binding tightly to the D-alanyl-D-alanine portion of the peptidoglycan precursor, preventing cross-linking.

Question 39

A 25-year-old male is brought to the trauma bay hemodynamically unstable following a motorcycle collision. Pelvic radiograph reveals an APC-III pelvic ring injury.

Despite application of a pelvic binder and initial fluid resuscitation, he remains hypotensive. What is the most common anatomical source of hemorrhage in this specific injury pattern?

Explanation

Up to 80-90% of bleeding in pelvic ring injuries originates from the low-pressure presacral venous plexus and cancellous bone edges. Arterial bleeding is less common but may require angioembolization if venous sources are controlled and the patient remains unstable.

Question 40

A 45-year-old male is brought to the ED after a motorcycle crash. He is hypotensive with a mechanically unstable pelvis (APC type III). A pelvic binder is applied. Where is the optimal anatomical position for the pelvic binder to maximize reduction and minimize complications?

Explanation

To effectively close the pelvic ring and control hemorrhage, a pelvic binder must be placed at the level of the greater trochanters. Placement over the iliac crests is ineffective and can paradoxically open the pelvis further in some fracture patterns.

Question 41

A 12-year-old obese male presents with left knee pain and an antalgic gait. Radiographs confirm a mild, stable slipped capital femoral epiphysis (SCFE) on the left. Which of the following is an absolute indication for prophylactic pinning of the contralateral asymptomatic hip?

Explanation

Prophylactic pinning of the contralateral hip is highly recommended in patients with endocrine disorders (e.g., hypothyroidism, renal osteodystrophy) due to the high risk of bilateral involvement. Other relative indications include young age (<10 years) and poor follow-up compliance.

Question 42

A 22-year-old collegiate soccer player undergoes primary ACL reconstruction using a bone-patellar tendon-bone (BTB) autograft. Six months postoperatively, she complains of anterior knee pain and a palpable click when extending the knee from 30 degrees to full extension. What is the most likely etiology?

Explanation

A Cyclops lesion (localized anterior arthrofibrosis) typically presents with an extension deficit and a terminal extension click or clunk after ACL reconstruction. Patellar clunk syndrome is classically associated with posterior stabilized total knee arthroplasty, not ACL reconstruction.

Question 43

A 68-year-old female presents with progressive clumsiness in her hands and a broad-based gait. MRI shows multilevel cervical spondylotic myelopathy from C3 to C6 with preservation of cervical lordosis. There is no significant anterior compression. What is the most appropriate surgical approach?

Explanation

In patients with multilevel cervical myelopathy and maintained cervical lordosis, posterior decompression (laminectomy and fusion or laminoplasty) is highly effective and avoids the higher morbidity associated with multilevel anterior procedures. A lordotic alignment allows the spinal cord to drift posteriorly away from anterior pathology.

Question 44

A 72-year-old male is 1 year status post a posterior-stabilized total knee arthroplasty. He complains of a painful catching sensation at the anterior knee when extending from a flexed position. Radiographs show well-fixed components with appropriate sizing. What is the most appropriate management?

Explanation

The patient has patellar clunk syndrome, caused by a fibrous nodule at the superior pole of the patella catching in the intercondylar box of a posterior-stabilized femur. Treatment is arthroscopic or open debridement of the fibrous nodule.

Question 45

A 45-year-old manual laborer presents with chronic radial-sided wrist pain. Radiographs reveal a scaphoid nonunion with radioscaphoid arthritis and capitolunate arthritis, but the radiolunate joint is preserved. This corresponds to a Stage III SNAC wrist. What is the most appropriate surgical intervention?

Explanation

Stage III SNAC involves radioscaphoid and midcarpal (capitolunate) arthritis with a preserved radiolunate joint. Proximal row carpectomy is contraindicated because the capitate head is arthritic; therefore, a four-corner fusion with scaphoid excision is the preferred salvage procedure.

Question 46

A 38-year-old male sustains a high-energy Schatzker VI tibial plateau fracture. The limb is grossly swollen, and ABI is 0.8. A CT angiogram reveals an intimal tear of the popliteal artery without complete occlusion, but distal pulses are diminished. What is the correct sequence of management?

Explanation

In the setting of a complex intra-articular fracture with a vascular injury, bone stability must be achieved rapidly, usually with a spanning external fixator, to protect the subsequent vascular repair. Definitive ORIF is delayed until soft tissues permit.

Question 47

A 14-year-old male presents with a painful mid-shaft femur mass. Radiographs show a permeative, diaphyseal lytic lesion with an "onion-skin" periosteal reaction. Core biopsy reveals small round blue cells. Cytogenetics demonstrate a t(11;22) translocation. What is the fusion protein generated by this translocation?

Explanation

The t(11;22) translocation is classic for Ewing sarcoma and results in the EWS-FLI1 fusion protein. SYT-SSX is seen in synovial sarcoma, and TLS-CHOP is associated with myxoid liposarcoma.

Question 48

A 6-year-old female falls from monkey bars and sustains a Gartland type III extension-type supracondylar humerus fracture. On examination, the hand is pink and well-perfused, but the radial pulse is absent. What is the next best step in management?

Explanation

A "pulseless, pink" hand after a displaced supracondylar humerus fracture indicates adequate collateral circulation. The next best step is urgent closed reduction and percutaneous pinning, as reduction often relieves kinking of the brachial artery and restores the pulse.

Question 49

A 28-year-old male sustains an acute, primarily ligamentous Lisfranc injury involving the first, second, and third tarsometatarsal joints after a severe twisting injury to the foot. Prospective randomized studies suggest which of the following treatments provides the best functional outcomes for this specific injury pattern?

Explanation

Level 1 evidence has demonstrated that primary arthrodesis of the medial 2 or 3 rays yields superior functional outcomes and lower revision rates compared to ORIF for purely ligamentous Lisfranc injuries.

Question 50

Recombinant human bone morphogenetic proteins (rhBMPs) are commonly used to enhance bone healing. Which specific intracellular signaling molecules are directly phosphorylated by the BMP receptor complex to translocate to the nucleus and activate osteogenic gene transcription?

Explanation

BMPs bind to serine/threonine kinase receptors that phosphorylate receptor-regulated Smads (Smad 1, 5, and 8). These then form a complex with Smad 4, which translocates to the nucleus to regulate transcription of osteogenic genes.

Question 51

A 60-year-old female experiences recurrent posterior dislocations following a primary total hip arthroplasty via a posterior approach. Intraoperative evaluation during revision surgery reveals that the acetabular component is placed in 30 degrees of inclination and 0 degrees of anteversion. What is the optimal target for acetabular component positioning to minimize dislocation risk?

Explanation

The classic Lewinnek "safe zone" for acetabular cup placement in THA is 40 +/- 10 degrees of inclination and 15 +/- 10 degrees of anteversion. The current cup is severely under-anteverted (0 degrees), predisposing to posterior instability.

Question 52

A 19-year-old competitive swimmer presents with bilateral shoulder pain and a sensation of "slipping" in all directions. Examination reveals a positive sulcus sign bilaterally that does not decrease with external rotation. What is the first-line treatment?

Explanation

The patient has multidirectional instability (MDI), classically presenting with generalized laxity and a sulcus sign. First-line management is conservative, utilizing a rigorous physical therapy program focused on dynamic stabilizers (rotator cuff and periscapular muscles).

Question 53

A 30-year-old carpenter suffers a laceration to the volar aspect of his index finger at the level of the proximal phalanx (Zone II). He undergoes surgical repair with a 4-strand core suture and an epitendinous repair. What is the most critical biomechanical benefit of adding a peripheral epitendinous suture?

Explanation

An epitendinous suture increases the overall strength of a flexor tendon repair by up to 50%, but its most critical biomechanical contributions are increasing resistance to gap formation and smoothing the repair site to improve gliding.

Question 54

A 72-year-old male presents with bilateral lower extremity pain and cramping that worsens with walking and improves with sitting. To differentiate neurogenic claudication from vascular claudication, a bicycle test is performed. Which of the following findings is characteristic of neurogenic claudication?

Explanation

In neurogenic claudication caused by lumbar spinal stenosis, symptoms are typically relieved by lumbar flexion, which increases the cross-sectional area of the spinal canal. Patients can cycle comfortably for longer periods when leaning forward.

Question 55

A 13-year-old obese male presents with a 3-week history of left knee pain and an antalgic gait. Exam shows obligatory external rotation of the left hip upon flexion. Radiographs confirm a severe left slipped capital femoral epiphysis (SCFE). Which of the following parameters is the strongest indication for prophylactic pinning of the asymptomatic contralateral hip?

Explanation

Prophylactic pinning of the contralateral hip is strongly indicated in patients with underlying endocrinopathies, such as hypothyroidism or renal osteodystrophy. Other relative indications include open triradiate cartilage and age less than 10 years, but endocrine disorders carry the highest risk of bilateral involvement.

Question 56

A 42-year-old male is brought to the trauma bay after a motorcycle collision. He is hemodynamically unstable with a heart rate of 120 bpm and BP of 80/50 mmHg. Pelvic radiograph reveals an APC-III pelvic ring injury. A pelvic binder is applied. To maximize reduction of the symphysis pubis and control hemorrhage, at what anatomic level should the pelvic binder be centered?

Explanation

Pelvic binders must be centered over the greater trochanters to effectively close an open-book pelvic ring injury. Placement over the iliac crests is incorrect and can cause paradoxical opening of the pelvic ring, worsening the hemorrhage.

Question 57

A 45-year-old manual laborer presents with chronic wrist pain. Radiographs reveal a scaphoid nonunion advanced collapse (SNAC) pattern with radioscaphoid and midcarpal arthritis, but preservation of the radiolunate articulation. Which of the following is the most appropriate surgical intervention?

Explanation

In a Stage II or III SNAC wrist with midcarpal and radioscaphoid arthritis but a preserved radiolunate joint, a four-corner fusion with scaphoid excision is indicated. Proximal row carpectomy (PRC) is contraindicated if there is significant capitate pole arthritis, which typically occurs in later stages.

Question 58

A 68-year-old female presents with a feeling of her knee "giving way" 2 years after a primary posterior-stabilized total knee arthroplasty. On examination, the knee is stable in extension but opens 12 mm to varus and valgus stress when flexed to 90 degrees. What is the most likely cause of this isolated flexion instability?

Explanation

Flexion instability in TKA is typically caused by an excessively increased flexion gap relative to the extension gap. Using an undersized femoral component in the anteroposterior dimension reduces the posterior condylar offset, thereby erroneously enlarging the flexion gap.

Question 59

A 55-year-old male of Asian descent presents with progressive clumsiness in his hands and a broad-based gait. Imaging shows multi-level ossification of the posterior longitudinal ligament (OPLL) from C3 to C6 causing severe cord compression. His cervical alignment demonstrates 15 degrees of kyphosis. What is the most appropriate surgical approach?

Explanation

In patients with cervical myelopathy secondary to OPLL who also have a kyphotic alignment (typically >13-15 degrees), an anterior decompression and fusion (e.g., corpectomy) is favored. Posterior approaches rely on cord drift, which does not effectively occur in kyphotic deformities because the K-line is negative.

Question 60

A 9-year-old male sustains a mid-substance ACL tear. He is Tanner Stage 1 with wide-open physes. Conservative management fails, and he experiences recurrent instability. Which surgical technique minimizes the risk of growth arrest and angular deformity?

Explanation

In Tanner Stage 1 or 2 patients with wide-open physes, physeal-sparing techniques like all-epiphyseal constructs are recommended to avoid crossing the growth plates. Transphyseal techniques are typically reserved for older patients nearing skeletal maturity.

Question 61

A 15-year-old female undergoes neoadjuvant chemotherapy followed by wide resection of a distal femur osteosarcoma. Histologic evaluation of the resected tumor specimen is performed to assess the extent of necrosis. According to the Huvos grading system, what percentage of tumor necrosis is the threshold for a "good" response to chemotherapy, correlating with improved survival?

Explanation

A 90% or greater tumor necrosis rate (Huvos Grade III or IV) following neoadjuvant chemotherapy is considered a good histologic response. This is the single most important prognostic factor for long-term survival in high-grade osteosarcoma.

Question 62

A 54-year-old male with poorly controlled diabetes presents with a swollen, erythematous, and warm right foot. He denies fever or open wounds. Radiographs show periarticular fragmentation, subluxation of the tarsometatarsal joints, and debris. According to the Eichenholtz classification, what stage does this represent, and what is the standard initial treatment?

Explanation

This patient has an acute Charcot arthropathy in the developmental/fragmentation stage (Eichenholtz Stage 1). The gold standard initial treatment is immobilization in a total contact cast and strict non-weight bearing to prevent further deformity until the acute inflammatory phase resolves.

Question 63

A 6-week-old female infant born breech undergoes a screening hip ultrasound. The Graf classification reveals an alpha angle of 45 degrees and a beta angle of 80 degrees. What does this indicate, and what is the most appropriate management?

Explanation

An alpha angle less than 60 degrees indicates acetabular dysplasia. Specifically, an alpha angle < 50 degrees and beta angle > 77 degrees denotes a Graf Type III hip (subluxated). The first-line treatment for a reducible dysplastic hip at this age is a Pavlik harness.

Question 64

In total joint arthroplasty, highly cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) is subjected to irradiation to improve wear resistance. However, irradiation creates free radicals that can cause oxidative degradation. Which post-irradiation thermal treatment completely eliminates free radicals but significantly reduces the mechanical properties (e.g., yield strength) of the polyethylene?

Explanation

Remelting (heating above the melting point of ~135 degrees C) completely extinguishes residual free radicals, enhancing oxidation resistance, but it decreases crystallinity, thereby reducing yield strength and fatigue resistance. Annealing heats below the melting point, preserving mechanical properties but leaving some free radicals.

Self Assessment Examination Adult S Review | Dr Hutaif - ...

Orthopedic Board Review MCQs (2026 Edition) - Part 2

Orthopedic Board Review MCQs (2026 Edition) - Part 2

Chapter Index