Arab Orthopaedic Board MCQs - Part 3

A 45-year-old male is brought to the trauma bay after an MVA. He is hypotensive (BP 70/40 mmHg) and tachycardic (HR 130 bpm). Primary survey reveals an unstable pelvis (APC III pattern). A pelvic binder is applied, and he receives 2 units of packed RBCs. His BP improves transiently but drops again to 75/45 mmHg. A FAST scan is negative. What is the most appropriate next step in management?

A 55-year-old female presents with progressive groin pain 4 years after undergoing a metal-on-metal total hip arthroplasty. Inflammatory markers are normal, and radiographs show no loosening. A MARS MRI reveals a solid-cystic pseudotumor in the periprosthetic soft tissues. Serum cobalt and chromium levels are elevated. What histological finding is most characteristic of this condition?

A 72-year-old male with a history of cervical spondylosis presents after a hyperextension injury to his neck from a low-level fall. He exhibits pronounced weakness in his upper extremities (deltoid and biceps 3/5, hand intrinsic 2/5) but retains 4/5 strength in his lower extremities. He has patchy sensory loss in his arms and hyperreflexia in his legs. MRI confirms spinal cord signal change at C4-C5 with severe preexisting stenosis. What is the most accurate statement regarding his condition?

A 5-week-old female infant is treated with a Pavlik harness for developmental dysplasia of the hip (DDH) of the left side (Graf Type IV). After 4 weeks of compliant harness wear, an ultrasound demonstrates that the left hip remains completely dislocated. What is the most appropriate next step in management?

A 24-year-old male presents with persistent wrist pain 8 months after a fall. Imaging reveals a proximal pole scaphoid nonunion. MRI demonstrates avascular necrosis (AVN) of the proximal pole, with the absence of punctate bleeding confirmed intraoperatively. Which of the following is the most appropriate surgical treatment?

A 9-year-old Tanner stage I boy sustains a midsubstance anterior cruciate ligament (ACL) tear. He complains of recurrent instability despite 3 months of aggressive physical therapy. You recommend surgical reconstruction. Which of the following techniques minimizes the risk of physeal growth arrest in this patient?

A 15-year-old boy presents with knee pain. Radiographs show a mixed lytic and sclerotic lesion in the distal femur with a 'sunburst' periosteal reaction. A core needle biopsy confirms conventional high-grade osteosarcoma. Which MRI sequence is most accurate for determining the precise longitudinal intramedullary extent (skip lesions) of the tumor for surgical planning?

A 55-year-old poorly controlled diabetic male presents with a red, hot, swollen right foot. He denies any penetrating trauma or fever. Radiographs reveal periarticular fragmentation, subluxation at the tarsometatarsal joints, and debris, but no osteomyelitis. Laboratory markers (WBC, CRP) are normal to minimally elevated. According to the Eichenholtz classification, what is his current stage and the most appropriate initial treatment?

You are treating a 30-year-old male with a lateral Hoffa fracture (coronal shear fracture of the lateral femoral condyle). You plan for open reduction and internal fixation. To achieve the most biomechanically stable construct for interfragmentary compression, what is the optimal trajectory for the screws?

Bone morphogenetic proteins (BMPs) play a crucial role in osteoblast differentiation and bone formation. Which of the following best describes the intracellular signaling pathway activated immediately upon BMP-2 binding to its serine/threonine kinase cell surface receptor?

A 12-year-old obese boy is diagnosed with a stable slipped capital femoral epiphysis (SCFE) of the left hip. During surgical counseling, the parents ask about the risk to the contralateral (right) hip. Prophylactic pinning of the contralateral hip is most strongly indicated if the patient has which of the following underlying conditions?

Following a zone II flexor tendon repair, an early active mobilization protocol is planned to prevent adhesions. To safely withstand the forces of early active motion without gap formation or rupture, what is the minimum number of core suture strands crossing the repair site recommended?

During a total knee arthroplasty for a valgus knee, trial implants are placed. The knee is balanced in flexion but remains significantly tight on the lateral side in full extension. Which of the following structures is the primary tether and should be released to address this specific asymmetry?

A 65-year-old female presents with neurogenic claudication and lower back pain. Imaging shows an L4-L5 grade I degenerative spondylolisthesis. Flexion-extension radiographs reveal 4 mm of dynamic translation. She fails 6 months of conservative management. According to the SPORT trial and current guidelines, what is the recommended surgical management?

A 48-year-old manual laborer presents with anterior shoulder pain and popping. MRI arthrogram demonstrates an isolated Type II SLAP lesion. He has no other rotator cuff pathology. After 4 months of failed physical therapy, surgical intervention is planned. What is the most appropriate surgical procedure for this patient?

A 35-year-old female presents with a large, destructive lytic lesion in her distal radius with cortical breakthrough. Biopsy confirms a Giant Cell Tumor (GCT) of bone. Neoadjuvant therapy with denosumab is considered to downstage the tumor prior to curettage. What is the specific mechanism of action of denosumab in treating this lesion?

A 28-year-old female sustains a twisting injury to her midfoot. Weight-bearing radiographs reveal a 3 mm diastasis between the base of the first and second metatarsals, with no obvious fractures (purely ligamentous Lisfranc injury). Which of the following treatments provides the best long-term functional outcome and lowest reoperation rate for this specific injury pattern?

Highly cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) was developed to improve the longevity of total hip arthroplasty implants. While increasing the radiation dose during manufacturing increases cross-linking and dramatically reduces volumetric wear, it also has a detrimental effect on which of the following material properties?

A 25-year-old male is admitted with a comminuted midshaft tibia fracture. Overnight, he requires escalating doses of IV opioids. On examination, his leg is tense, and he has severe pain with passive stretch of the extensor hallucis longus. His blood pressure is 110/70 mmHg. Intracompartmental pressure monitoring of the anterior compartment yields a reading of 45 mmHg. What is his Delta P, and what is the appropriate management?

A 7-year-old boy is diagnosed with Legg-Calve-Perthes disease. According to the Herring Lateral Pillar Classification, which of the following radiographic findings represents a Type C pillar, and what does it signify?

A 5-year-old girl with developmental dysplasia of the hip (DDH) presents with an acetabular index of 40 degrees and primarily anterolateral deficiency. The surgeon plans an incomplete pericapsular osteotomy that relies on the flexibility of the triradiate cartilage to hinge the acetabular roof downward. Which of the following osteotomies is being described?

A 55-year-old man of Asian descent presents with progressive clumsiness in his hands and a positive Hoffman's sign. A CT scan of the cervical spine confirms ossification of the posterior longitudinal ligament (OPLL). Which of the following conditions is most strongly associated with this pathology?

A 48-year-old manual laborer presents with chronic wrist pain years after an untreated scapholunate ligament tear. Radiographs show joint space narrowing extending across the entire radioscaphoid articulation. The capitolunate and radiolunate joints appear completely preserved. What is the correct staging for this condition?

A 52-year-old diabetic patient presents with a swollen, erythematous, and warm foot. Radiographs demonstrate fragmentation of the tarsometatarsal joints, periarticular debris, and joint subluxation. There are no skin ulcerations. What is the most appropriate initial management?

A 25-year-old woman is diagnosed with a giant cell tumor (GCT) of the distal femur. Her surgeon considers neoadjuvant treatment with Denosumab prior to curettage to facilitate intralesional resection. What is the exact mechanism of action of Denosumab?

During the physical examination of a patient with a knee injury, the dial test reveals a 15-degree increase in external rotation of the tibia at 30 degrees of knee flexion compared to the uninjured side. However, at 90 degrees of knee flexion, the external rotation is symmetric bilaterally. What injury pattern does this indicate?

A 30-year-old male is brought to the trauma bay following a high-speed motor vehicle collision. He has an anteroposterior compression (APC III) pelvic ring injury and is hemodynamically unstable. A pelvic binder is applied, but he remains hypotensive. FAST exam is negative. What is the most common anatomical source of massive hemorrhage in this clinical scenario?

Demineralized bone matrix (DBM) is commonly used in orthopedic procedures as a bone graft extender. Processing allograft bone into DBM preserves which primary biologic property for bone healing?

A 12-year-old boy undergoes in-situ pinning for a stable Slipped Capital Femoral Epiphysis (SCFE) using a single cannulated screw. If the screw inadvertently penetrates the anterosuperior quadrant of the femoral head during the procedure, the patient is at highest risk for developing which of the following complications?

In complex total hip arthroplasty, a dual mobility articulation may be utilized to decrease the risk of dislocation. The primary biomechanical mechanism by which a dual mobility construct prevents instability is:

A hand surgeon is repairing a complete laceration of the flexor digitorum profundus (FDP) tendon in Zone II. According to biomechanical studies, the tensile strength of the repair before clinical failure is most directly proportional to which of the following factors?

A 68-year-old male presents with bilateral lower extremity pain with walking. You are attempting to distinguish between neurogenic claudication (due to lumbar spinal stenosis) and vascular claudication. Which of the following clinical findings strongly favors neurogenic claudication?

A 28-year-old man sustains a talar neck fracture following a fall from a height. Radiographs reveal a displaced fracture of the talar neck with subluxation of the subtalar joint, but the tibiotalar and talonavicular joints remain perfectly congruent. According to the Hawkins classification, what is the approximate historical risk of developing avascular necrosis (AVN) of the talar body?

During the correction of idiopathic congenital talipes equinovarus (clubfoot) using the Ponseti method, the deformities must be corrected in a specific anatomical sequence. Which of the following components is addressed LAST in the treatment algorithm?

A 45-year-old female presents with symptomatic hallux valgus that has failed non-operative management. Weight-bearing radiographs reveal a Hallux Valgus Angle (HVA) of 42 degrees and an Intermetatarsal Angle (IMA) of 18 degrees. Based on these parameters, which of the following is the most appropriate surgical intervention?

A 15-year-old boy presents with progressive thigh pain. Radiographs demonstrate a permeative diaphyseal lesion of the femur with an 'onion skin' periosteal reaction. A biopsy shows sheets of small round blue cells. Which chromosomal translocation is most characteristically associated with this tumor?

Three months after open reduction and internal fixation of a distal radius fracture with a volar locking plate, a patient develops a sudden inability to extend the interphalangeal joint of the thumb. What is the most common iatrogenic cause of this specific complication in the setting of volar plating?

According to the 2018 International Consensus Meeting (ICM) criteria for Periprosthetic Joint Infection (PJI), which of the following findings is considered a MAJOR criterion that independently confirms the diagnosis of PJI?

Biomechanical studies have demonstrated that an un-repaired complete radial tear of the medial meniscus posterior root alters the contact mechanics and joint kinematics of the knee most similarly to which of the following conditions?

Bone Morphogenetic Proteins (BMPs) play a crucial role in osteoinduction and fracture healing. Biologically, BMPs are members of which of the following larger signaling superfamilies?

A 12-year-old female presents with back pain and a slip angle of 55 degrees on standing lateral radiographs, consistent with high-grade dysplastic spondylolisthesis. Which of the following is the most characteristic physical exam finding associated with this condition?

In a Young-Burgess Anterior Posterior Compression Type III (APC III) pelvic ring injury, which of the following ligamentous complexes is definitively disrupted compared to an APC II injury?

A 65-year-old man undergoes primary THA with a ceramic-on-ceramic bearing. At 2-year follow-up, he complains of a reproducible squeaking noise when walking. Which of the following factors is most strongly associated with squeaking in ceramic-on-ceramic total hip arthroplasty?

A 32-year-old manual laborer presents with dorsal wrist pain. Radiographs reveal sclerosis and fragmentation of the lunate without carpal collapse. Ulnar variance is determined to be minus 3 mm. Which of the following surgical interventions is most appropriate for this Lichtman Stage II Kienböck's disease?

A 14-year-old boy presents with a painful, swollen thigh. Radiographs show a permeative diaphyseal lesion with a periosteal 'onion-skin' reaction in the femur. Biopsy confirms Ewing sarcoma. Which of the following chromosomal translocations is most characteristic of this diagnosis?

A 6-week-old female is treated with a Pavlik harness for developmental dysplasia of the hip. At the 1-week follow-up, the mother notes the infant has stopped kicking her left leg, and the knee remains extended. Which of the following is the most likely cause?

During the incorporation of a cortical bone allograft, what is the term used to describe the process where osteoclasts resorb the dead bone and osteoblasts simultaneously lay down new bone in the cutting cone?

A 24-year-old football player sustains a valgus blow to the knee. MRI shows a complete tear of the medial collateral ligament (MCL) and a tear of the posterior oblique ligament (POL). What is the primary biomechanical function of the POL?

A 55-year-old diabetic patient presents with a warm, swollen, erythematous foot. Radiographs reveal fragmentation of the midfoot, periarticular debris, and subluxation of the tarsometatarsal joints. According to the Eichenholtz classification, what stage is this patient in?

You are treating a 45-year-old male with a posteromedial shear fracture of the tibial plateau (Schatzker IV variant). Which surgical approach is most appropriate for direct visualization and buttress plating of this specific fragment?

A 50-year-old man presents with neck pain radiating down his right arm. Examination reveals weakness in wrist flexion and finger extension, with diminished triceps reflex and numbness in the middle finger. Which cervical nerve root is most likely compressed?

A 68-year-old woman presents 1 year after a posterior-stabilized total knee arthroplasty with a painful catching sensation when extending her knee from a flexed position. What is the most likely diagnosis?

Prophylactic pinning of the contralateral hip in a patient with a unilateral Slipped Capital Femoral Epiphysis (SCFE) is most strongly indicated in a patient with which of the following underlying conditions?

Following a Zone II flexor tendon repair, which rehabilitation protocol initially uses dynamic flexion traction via rubber bands and active extension within the limits of a dorsal blocking splint?

Galvanic corrosion in orthopedic implants is most likely to occur when which of the following combinations of metals are placed in direct physical contact within the body?

A 22-year-old collegiate baseball pitcher presents with posterior shoulder pain during the late cocking phase of throwing. Examination reveals a significant loss of internal rotation (GIRD) and a positive relocation test. MRI shows undersurface fraying of the posterior supraspinatus and anterior superior labrum. What is the most likely diagnosis?

A 65-year-old female sustains a distal radius fracture. Radiographs show a volar marginal articular fracture fragment with volar subluxation of the carpus. Which of the following eponymous terms correctly describes this fracture pattern?

A 60-year-old male is diagnosed with a Grade II conventional chondrosarcoma of the proximal femur. Which of the following is the standard of care for surgical treatment of this lesion?

In a 2-year-old child, why does acute hematogenous osteomyelitis of the proximal femur carry a high risk of rapidly developing into septic arthritis of the hip?

According to Lewinnek, what is the historically described 'safe zone' for acetabular component positioning in total hip arthroplasty to minimize the risk of dislocation?

A 15-year-old male presents with increasing middle back pain and a visible rounding of his spine. Standing lateral radiographs reveal thoracic kyphosis of 60 degrees. According to the Sorensen criteria, which of the following radiographic findings must be present to establish a definitive diagnosis of Scheuermann's kyphosis?

During a posterior-stabilized total knee arthroplasty, the surgeon uses spacer blocks to assess gap kinematics. With the trial components in place, the extension gap is perfectly symmetric and stable. However, when the knee is flexed to 90 degrees, the joint is grossly unstable both medially and laterally. Which of the following technical errors is the most likely cause of this isolated flexion gap looseness?

A 35-year-old male sustains a vertically unstable (Tile C) pelvic ring disruption in a motor vehicle collision. He arrives at the trauma bay hypotensive and tachycardic. To control severe venous bleeding, emergent preperitoneal pelvic packing is performed. Into which specific anatomic space are the laparotomy sponges packed?

An electromyographic (EMG) study reveals a Martin-Gruber anastomosis. Which of the following accurately describes the anatomic pathway of this common neural communication?

A 14-year-old boy presents with a painful, swollen left mid-thigh. Radiographs reveal a permeative, destructive diaphyseal lesion of the femur with a laminated 'onion-skin' periosteal reaction. Biopsy demonstrates a proliferation of small round blue cells. Which of the following chromosomal translocations is the most common genetic hallmark of this tumor?

When evaluating the viscoelastic properties of tendons and ligaments, which of the following statements best defines the biomechanical phenomenon of 'stress relaxation'?

During a medial patellofemoral ligament (MPFL) reconstruction for recurrent patellar instability, the surgeon seeks the anatomic femoral attachment site (Schöttle's point) using fluoroscopy. Anatomically, where does the MPFL originate on the medial femur?

A 25-year-old male is involved in a high-speed motor vehicle collision. CT of the cervical spine shows a traumatic spondylolisthesis of the axis (Hangman's fracture) with severe angulation but minimal translation of C2 on C3. MRI reveals a disrupted C2-3 disc space and an intact anterior longitudinal ligament. This is classified as a Levine-Edwards Type IIA fracture. What is the most appropriate initial management?

A 60-year-old man presents with a painful, severe, and rigid flatfoot deformity. Examination reveals an inability to perform a single-leg heel raise, and the heel remains in fixed valgus on double-leg heel raise. Weight-bearing radiographs demonstrate profound osteoarthritis of the subtalar, talonavicular, and calcaneocuboid joints. What is the most appropriate definitive surgical intervention?

In the management of Slipped Capital Femoral Epiphysis (SCFE), prophylactic in situ pinning of the asymptomatic contralateral hip is widely debated. However, there is strong consensus to perform prophylactic pinning in which of the following patient presentations?

In total hip arthroplasty, the use of highly cross-linked polyethylene (HXLPE) has significantly reduced volumetric wear rates compared to conventional ultra-high molecular weight polyethylene (UHMWPE). However, the cross-linking and subsequent thermal processing alter the mechanical properties of the material. What is the primary mechanical disadvantage of highly cross-linked polyethylene?

A 'terrible triad' injury of the elbow involves a posterior elbow dislocation, radial head fracture, and coronoid fracture. During the standard surgical reconstruction via a single lateral approach, what is the generally recommended sequence of fixation to restore elbow stability?

Vitamin D plays a critical role in bone metabolism. Following synthesis in the skin or absorption from the gut, it undergoes two sequential hydroxylations to become biologically active. Which specific enzyme is responsible for the final conversion to 1,25-dihydroxyvitamin D (calcitriol)?

Flexor tendon lacerations of the hand are categorized into anatomic zones to guide prognosis and treatment. Which zone, containing both the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) tendons within a tight fibro-osseous sheath, is historically referred to as 'no man's land'?

A 65-year-old male presents with deteriorating handwriting, dropping objects, and a subjective feeling of lower extremity stiffness. Physical examination demonstrates hyperreflexia in the patellar and Achilles tendons. Striking the distal brachioradialis tendon elicits no reflex in the brachioradialis itself, but produces a brisk spontaneous flexion of the fingers. This specific finding (the inverted brachioradialis reflex) indicates spinal cord compression at which specific level?

A 24-year-old elite overhead throwing athlete presents with deep shoulder pain and mechanical catching sensations. MR arthrography suggests a SLAP (Superior Labrum Anterior Posterior) tear. Diagnostic arthroscopy reveals a Type II SLAP lesion. Which of the following accurately describes a Type II SLAP tear according to the Snyder classification?

A 32-year-old male sustains a high-energy vertical shear injury to his foot and ankle. Radiographs reveal a displaced talar neck fracture with subluxation of the subtalar joint and complete dislocation of the tibiotalar joint. According to the Hawkins classification, this is a Type III fracture. What is the approximate reported incidence of avascular necrosis (AVN) of the talar body associated with this specific injury pattern?

A 4-week-old female infant is diagnosed with developmental dysplasia of the hip (DDH) after a positive Ortolani maneuver. A Pavlik harness is applied. At the one-week follow-up, it is noted that the anterior straps are excessively tight, holding the hips in over 120 degrees of flexion. Which peripheral nerve is most at risk for palsy due to this specific positioning error?

Periprosthetic joint infections are notoriously difficult to eradicate due to the formation of bacterial biofilms on the implant surface. While the exopolysaccharide matrix provides a physical barrier, what is considered the primary biological mechanism by which biofilms convey profound resistance to systemic bactericidal antibiotics?

A 68-year-old male presents with a pathologic fracture of the proximal humerus. Radiographs reveal a large 'punched-out' lytic lesion. Laboratory workup shows hypercalcemia, an elevated serum creatinine, and a monoclonal spike on serum protein electrophoresis (SPEP). In the pathophysiology of this disease, what is the primary mechanism driving the extensive osteolysis?