+967-774203774 [email protected]
العربية
Part of the Master Guide

Arab Board Orthopedic B Review | Dr Hutaif General Orth -...

Arab Orthopaedic Board MCQs - Part 2

27 Apr 2026 81 min read 76 Views
Arab Ortho Board MCQs - Part 1

Key Takeaway

This topic focuses on Arab Orthopaedic Board MCQs - Part 2, Practice Arab Orthopaedic Board MCQs Part 2. Review orthopedic surgery questions 51 to 100 for your board exam preparation.

Arab Orthopaedic Board MCQs - Part 2

Comprehensive 100-Question Exam


00:00

Start Quiz

Question 1

During an anterior intrapelvic (modified Stoppa) approach for an acetabular fracture, significant bleeding occurs near the posterior aspect of the superior pubic ramus. This is most likely due to injury to an anastomosis between which of the following vessel systems?





Explanation

The corona mortis is a critical vascular anastomosis between the external iliac (or inferior epigastric) and the obturator systems. It is consistently located on the posterior aspect of the superior pubic ramus and is highly vulnerable to injury during the modified Stoppa or ilioinguinal approach.

Question 2

In a 20-month-old child undergoing an anterolateral (Smith-Petersen) approach for open reduction of developmental dysplasia of the hip, what is the primary extra-articular block to concentric reduction that must be released first?





Explanation

The iliopsoas tendon is a primary extra-articular obstacle to reduction in DDH as it passes over the anterior capsule, causing an hourglass constriction of the joint. It is routinely released during the Smith-Petersen approach before addressing intra-articular obstacles like the ligamentum teres, transverse acetabular ligament, and pulvinar.

Question 3

An 82-year-old male sustains a Type II odontoid fracture with 4 mm of posterior displacement following a low-energy fall. He has no neurologic deficits but has severe neck pain. What is the most appropriate management?





Explanation

Type II odontoid fractures in the elderly (>70 years) have an unacceptably high nonunion rate with conservative management and poor tolerance/high mortality associated with halo vests. Anterior screw fixation has lower success rates due to osteopenia. Posterior C1-C2 fusion provides the highest union rates and best functional outcomes for displaced Type II fractures in this demographic.

Question 4

A 25-year-old soccer player is undergoing anterior cruciate ligament (ACL) reconstruction. The surgeon considers an anterolateral ligament (ALL) reconstruction for residual pivot shift. Which of the following accurately describes the anatomic attachment sites of the ALL?





Explanation

The anterolateral ligament (ALL) originates slightly posterior and proximal to the lateral femoral epicondyle and inserts on the proximal tibia midway between Gerdy's tubercle and the fibular head. It acts as an important secondary restraint to internal tibial rotation.

Question 5

During a posterior-stabilized total knee arthroplasty using an anterior referencing system, trial components are inserted. The knee is stable and symmetric in extension, but the flexion gap is unacceptably tight, preventing flexion beyond 90 degrees. What is the most appropriate next step to balance the knee?





Explanation

In a TKA, a tight flexion gap with a perfectly balanced extension gap can be addressed by downsizing the femoral component (which decreases the anteroposterior dimension of the femur without affecting the distal cut/extension gap) or by increasing the posterior tibial slope. Resecting more distal femur would loosen the extension gap.

Question 6

A 55-year-old female presents with a progressive painful flatfoot deformity. Examination shows she is unable to perform a single-leg heel rise. Radiographs demonstrate collapse of the medial longitudinal arch, talonavicular unroofing of 40%, and significant forefoot abduction. What is the most appropriate surgical intervention?





Explanation

The patient has Stage IIb adult-acquired flatfoot deformity (posterior tibial tendon dysfunction), characterized by flexible flatfoot with significant forefoot abduction (>30% talonavicular unroofing). Stage IIb requires addressing the medial column (FDL transfer) as well as correcting both the hindfoot valgus (medial displacement calcaneal osteotomy) and forefoot abduction (lateral column lengthening).

Question 7

A 45-year-old female presents with recurrent numbness in her thumb, index, and middle fingers 6 months after an open carpal tunnel release. EMG confirms severe median neuropathy at the wrist, worse than preoperative levels. Surgical exploration reveals the median nerve is tethered by dense scar tissue, but the flexor retinaculum is fully released. Following neurolysis, which of the following is the most appropriate vascularized flap to prevent re-scarring?





Explanation

The hypothenar fat pad flap is commonly used for recurrent carpal tunnel syndrome with severe perineural scarring. It provides a local, vascularized adipose tissue layer to wrap the median nerve, preventing re-tethering to the overlying structures and improving nerve gliding.

Question 8

A 15-year-old boy presents with knee pain. Radiographs reveal an aggressive, purely lytic lesion in the distal femoral metaphysis. MRI demonstrates multiple fluid-fluid levels within the lesion. Core needle biopsy shows large, blood-filled cystic spaces with septa containing highly pleomorphic, spindle-shaped cells producing fine, lace-like osteoid. What is the most likely diagnosis?





Explanation

The presence of a purely lytic lesion with fluid-fluid levels strongly suggests a differential of Aneurysmal Bone Cyst (ABC) or Telangiectatic Osteosarcoma. The key distinguishing feature on histology is the presence of malignant, pleomorphic cells producing lace-like osteoid in the septa, which is diagnostic for Telangiectatic Osteosarcoma.

Question 9

According to Perren's strain theory, what is the required microstrain environment at the fracture site to promote primary (osteonal) bone healing?





Explanation

Perren's strain theory states that primary (osteonal) bone healing occurs under conditions of absolute stability, which corresponds to a local tissue strain of less than 2%. Secondary bone healing (callus formation) occurs in a relatively stable environment with strain between 2% and 10%.

Question 10

A 30-year-old male sustains a vertical, displaced (Pauwels Type III) femoral neck fracture. To maximize biomechanical stability and reduce the risk of shear-induced nonunion, which of the following fixation constructs is most appropriate?





Explanation

Pauwels Type III fractures (vertical shear fractures) in young adults are highly unstable. A Dynamic Hip Screw (DHS) with an anti-rotation screw provides superior biomechanical stability against vertical shear forces compared to three parallel cancellous screws, reducing the risk of varus collapse and nonunion.

Question 11

A 12-year-old boy presents with an unstable slipped capital femoral epiphysis (SCFE) and is unable to bear weight. The surgeon performs an in-situ pinning and an open capsulotomy to decompress the joint. This capsulotomy is primarily intended to protect the terminal branches of which artery to prevent avascular necrosis?





Explanation

An unstable SCFE carries a high risk of avascular necrosis (AVN) due to kinking or tamponade of the retinacular vessels. These vessels, particularly the lateral epiphyseal artery, are terminal branches of the medial circumflex femoral artery (MCFA). Capsulotomy reduces intracapsular pressure to maintain perfusion.

Question 12

A 65-year-old woman presents with neurogenic claudication. Imaging reveals a Grade I degenerative spondylolisthesis at L4-L5. Which nerve root is most commonly compressed in this specific pathology, and where does the compression typically occur?





Explanation

In degenerative spondylolisthesis (most common at L4-L5), the pathology involves central canal or lateral recess stenosis due to facet hypertrophy and ligamentum flavum buckling. This primarily compresses the traversing nerve root (L5) in the lateral recess. This contrasts with isthmic spondylolisthesis, where the exiting root (L4 in L4-5, or L5 in L5-S1) is compressed in the foramen.

Question 13

A 22-year-old collegiate baseball pitcher presents with deep shoulder pain and a 'dead arm' sensation. MR arthrogram demonstrates a Type II SLAP lesion. Following 6 months of failed physical therapy, which of the following is the most generally accepted surgical management for this patient profile?





Explanation

In young overhead throwing athletes (e.g., <25 years old), arthroscopic SLAP repair remains the preferred initial surgical treatment for a symptomatic Type II SLAP tear that fails conservative care, aiming to restore the anatomic mechanics critical for throwing. Biceps tenodesis is often preferred in older patients or non-throwers.

Question 14

A 68-year-old male with a metal-on-polyethylene total hip arthroplasty implanted 5 years ago presents with new-onset groin pain. MRI reveals a large cystic pseudotumor. Aspiration yields cloudy fluid with negative cultures but markedly elevated cobalt and chromium levels. What is the most likely source of the metal debris?





Explanation

In a metal-on-polyethylene (MoP) total hip arthroplasty presenting with elevated metal ions and adverse local tissue reaction (ALTR/pseudotumor), the primary source of metal debris is wear and corrosion at the head-neck modular junction (taper), known as trunnionosis.

Question 15

According to the Lauge-Hansen classification, what is the sequence of injury in a Supination-External Rotation (SER) ankle fracture?





Explanation

The Lauge-Hansen SER sequence is: Stage 1) Anterior inferior tibiofibular ligament (AITFL) rupture; Stage 2) Spiral/short oblique fracture of the lateral malleolus; Stage 3) Posterior inferior tibiofibular ligament (PITFL) tear or posterior malleolus fracture; Stage 4) Medial malleolus fracture or deltoid ligament tear.

Question 16

A 28-year-old male undergoes open reduction and internal fixation for a volar Barton's fracture. The surgeon must carefully stabilize the volar lunate facet fragment to prevent carpal subluxation. Which critical radiocarpal ligament originates from this specific fragment?





Explanation

The short radiolunate (SRL) ligament originates from the volar margin of the lunate facet of the distal radius and inserts onto the volar lunate. It is the primary stabilizer preventing volar subluxation of the lunate. Failure to fix this fragment allows the lunate to subluxate volarly with the fragment.

Question 17

A 45-year-old female undergoes a wide resection of a proximal tibial tumor. Histologic examination reveals a cartilaginous matrix with plump nuclei, binucleate cells, and myxoid changes permeating through trabecular bone. What is the most appropriate adjuvant therapy following negative wide surgical margins?





Explanation

The histologic description is classic for a conventional chondrosarcoma. Conventional chondrosarcomas are notably resistant to both chemotherapy and radiation therapy. The mainstay and only definitive treatment is wide surgical excision. Adjuvant therapy is typically not indicated.

Question 18

When evaluating the biomechanical properties of a tendon under tensile testing, the total area under the stress-strain curve represents which of the following material properties?





Explanation

The area under the stress-strain curve represents the toughness of a material, which is the total amount of strain energy absorbed by the material prior to failure. The elastic modulus is the slope of the linear elastic region, and the ultimate tensile strength is the peak stress achieved.

Question 19

A 26-year-old male polytrauma patient sustains an open book pelvic fracture and bilateral closed femoral shaft fractures. His blood pressure is 80/40 mmHg, HR 130 bpm, base deficit -10, and lactate 5 mmol/L. Following initial pelvic binding and resuscitation, his physiologic parameters remain unchanged. What is the most appropriate next step in the orthopedic management of his femoral fractures?





Explanation

This patient is in extremis based on damage control orthopedics (DCO) criteria (persistent shock, severe base deficit, elevated lactate). Early total care (immediate IM nailing) poses a severe 'second hit' risk. The standard DCO approach for major long bone fractures in an unstable polytrauma patient is rapid temporary stabilization with external fixation.

Question 20

Which of the following is NOT considered one of Catterall's classic 'head-at-risk' radiographic signs in Legg-Calvé-Perthes disease?





Explanation

Catterall's 'head-at-risk' signs predict a poor outcome and hinge abduction in Perthes disease. They include Gage's sign (V-shaped defect in the lateral epiphysis), lateral calcification, lateral subluxation of the head, horizontal growth plate, and diffuse metaphyseal reaction (cysts). Coxa magna (enlarged head) is a later sequela, not a predictive 'head-at-risk' sign.

Question 21

A 12-year-old boy presents with a painful diaphyseal femur lesion with an 'onion skin' periosteal reaction on radiographs. Core needle biopsy demonstrates small round blue cells that are strongly CD99 positive. Which of the following cytogenetic abnormalities is most characteristic of this tumor?





Explanation

Ewing sarcoma is characterized by the t(11;22)(q24;q12) translocation, creating the EWS-FLI1 fusion protein. t(X;18) is associated with synovial sarcoma. t(2;13) is seen in alveolar rhabdomyosarcoma. t(12;16) is associated with myxoid liposarcoma. t(9;22) is found in extraskeletal myxoid chondrosarcoma.

Question 22

A 14-year-old obese boy presents with an acute-on-chronic slipped capital femoral epiphysis (SCFE) of the right hip. He is unable to bear weight even with the use of crutches. He is treated with single in-situ screw fixation. Which of the following clinical factors places him at the highest risk for developing avascular necrosis (AVN) of the femoral head?





Explanation

The inability to bear weight defines an 'unstable' SCFE according to the Loder classification. Unstable SCFE is the single greatest predictor for the development of AVN, with rates up to nearly 50%, due to the increased risk of disruption to the retinacular blood supply.

Question 23

In a posteromedial shear fracture of the tibial plateau (Schatzker IV), which surgical approach and fixation strategy provides the most biomechanically stable construct to resist the primary deforming forces?





Explanation

Posteromedial shear fragments in tibial plateau fractures are subjected to vertical shear forces, especially during knee flexion. They are best stabilized through a posteromedial approach using a posterior anti-glide plate placed at the apex of the fracture, which biomechanically neutralizes these shear forces.

Question 24

A 45-year-old man falls from a height and sustains a Type II odontoid fracture. Displacement is 6 mm posteriorly. Which of the following conditions is an absolute contraindication to anterior odontoid screw fixation?





Explanation

Anterior odontoid screw fixation relies entirely on an intact transverse atlantal ligament (TAL) to maintain C1-C2 stability postoperatively. If the TAL is ruptured (evidenced by MRI or C1 lateral mass displacement >6.9 mm), anterior screw fixation is contraindicated, and posterior C1-C2 fusion is required.

Question 25

During a primary total knee arthroplasty, the surgeon assesses the gaps and notes the knee is tight in flexion but well-balanced and stable in extension. Which of the following intraoperative maneuvers is most appropriate to balance the knee?





Explanation

A tight flexion gap with a balanced extension gap requires a reduction in the posterior femoral offset. Downsizing the femoral component (utilizing anterior referencing) removes more posterior femoral condylar bone, thereby increasing the flexion gap without affecting the extension gap.

Question 26

A 35-year-old man presents with inability to cross his fingers and a clawing deformity of the ring and little fingers following a deep glass laceration to the mid-forearm. In a normal hand, which of the following intrinsic muscles is primarily responsible for preventing this clawing posture?





Explanation

Clawing (hyperextension of MCP and flexion of IP joints) in an ulnar neuropathy occurs because the lumbricals to the ring and small fingers are denervated. The lumbricals normally flex the MCP and extend the IP joints. Loss of this function leaves the extensor digitorum communis unopposed at the MCP, and FDP/FDS unopposed at the IPs.

Question 27

A 60-year-old man has a massive, irreparable posterosuperior rotator cuff tear. He has intact subscapularis and teres minor function. He complains primarily of an inability to actively elevate his arm above 40 degrees but has minimal pain (pseudoparalysis). Which of the following is the most appropriate surgical treatment?





Explanation

In older patients with a massive, irreparable posterosuperior rotator cuff tear and pseudoparalysis (inability to actively elevate >90 degrees), a reverse total shoulder arthroplasty (RTSA) provides a stable, fixed fulcrum and restores active elevation by maximizing the mechanical advantage of the deltoid muscle.

Question 28

In the anatomic stabilization of the tarsometatarsal articulation, which of the following ligaments provides the primary stabilization to the Lisfranc joint complex?





Explanation

The Lisfranc ligament is an interosseous ligament that runs from the lateral aspect of the medial cuneiform to the medial base of the second metatarsal. It is the thickest, strongest, and primary stabilizer of the tarsometatarsal articulation. There is no transverse intermetatarsal ligament between the 1st and 2nd metatarsals.

Question 29

When selecting a bone graft or substitute for an osseous defect, which of the following materials possesses osteoinductive, osteoconductive, and osteogenic properties?





Explanation

Autograft is the only bone graft material that possesses all three essential properties for bone healing: osteoconduction (provides a physical scaffold), osteoinduction (provides growth factors like BMPs to stimulate differentiation), and osteogenesis (supplies live osteoblasts and mesenchymal stem cells).

Question 30

A 65-year-old woman undergoes primary total hip arthroplasty via a posterior approach. Postoperatively, she experiences recurrent posterior dislocations. Radiographic evaluation shows the acetabular component in 45 degrees of abduction and 0 degrees of anteversion. Which of the following revision strategies is most appropriate?





Explanation

The acetabular component is relatively retroverted (0 degrees of anteversion instead of the normal 15-20 degrees), strongly predisposing the patient to posterior dislocation. The primary architectural cause of instability must be corrected; thus, revising the acetabular component to increase anteversion is required.

Question 31

In a 13-year-old female with adolescent idiopathic scoliosis, which of the following radiographic parameters best defines a 'structural' minor curve that must be included in the fusion construct according to the Lenke classification system?





Explanation

The Lenke classification defines a minor curve as structural if it lacks sufficient flexibility. Specifically, if the coronal Cobb angle remains > 25 degrees on lateral side-bending radiographs, it is considered structural and should be included in the fusion construct.

Question 32

A 30-year-old man sustains a closed spiral fracture of the distal third of the humeral shaft (Holstein-Lewis fracture). On examination, he is unable to actively extend his wrist or fingers. He is scheduled for open reduction and internal fixation. During surgical exploration, where is the radial nerve most likely to be found in relation to the lateral intermuscular septum?





Explanation

In a Holstein-Lewis fracture, the distal fragment typically migrates proximally. The radial nerve is at high risk of entrapment or injury as it passes from the posterior compartment to the anterior compartment, piercing the lateral intermuscular septum approximately 10 cm proximal to the radiocapitellar joint, which is often at the level of this specific fracture.

Question 33

A 42-year-old man presents with a painful, swollen right index finger 3 days after a puncture wound. Which of the following is NOT one of Kanavel's cardinal signs of purulent flexor tenosynovitis?





Explanation

Kanavel's four cardinal signs of purulent flexor tenosynovitis are: 1) fusiform (sausage) swelling of the digit, 2) flexed resting posture, 3) exquisite tenderness along the course of the flexor tendon sheath, and 4) pain with PASSIVE extension. Pain on active extension is not a classical sign.

Question 34

A 28-year-old woman presents with a pathologic fracture of the proximal phalanx of her ring finger after minor trauma. Radiographs show a well-circumscribed, centrally located radiolucent lesion with stippled calcifications. Which of the following is the most appropriate definitive management for the underlying lesion?





Explanation

The clinical and radiographic presentation is classic for an enchondroma, the most common primary bone tumor of the hand. Standard definitive treatment involves allowing the fracture to heal (or treating concurrently depending on stability), followed by intralesional curettage and filling the defect with bone graft or a bone substitute.

Question 35

A 22-year-old soccer player undergoes anterior cruciate ligament (ACL) reconstruction using a bone-patellar tendon-bone autograft. To avoid a postoperative 'cyclops lesion' and loss of terminal knee extension, which technical step is most critical during tunnel preparation?





Explanation

A cyclops lesion (localized anterior arthrofibrosis) and graft impingement in extension occur when the tibial tunnel is placed too far anteriorly. The anterior margin of the tibial tunnel must be placed posterior to the intercondylar roof (Blumensaat's line) with the knee in full extension.

Question 36

A 40-year-old hemodynamically unstable male presents after a motorcycle accident. Pelvic radiographs show a symphysis pubis diastasis of 4 cm and widening of the anterior sacroiliac joints bilaterally, with intact posterior SI ligaments (APC Type II). What is the primary source of life-threatening hemorrhage in this specific injury pattern?





Explanation

In anteroposterior compression (APC) pelvic ring injuries (open book), the most common source of massive hemorrhage is the presacral venous plexus and bleeding from raw cancellous bone. Venous bleeding accounts for up to 80-90% of pelvic hemorrhage. Arterial bleeding (e.g., superior gluteal) is more common in posterior ring injuries (e.g., vertical shear).

Question 37

Titanium alloy (Ti-6Al-4V) is frequently used in orthopedic implants. Compared to cobalt-chromium (CoCr) alloys, titanium alloy exhibits which of the following biomechanical characteristics?





Explanation

Titanium alloys have a lower modulus of elasticity compared to Cobalt-Chromium or Stainless Steel, making them closer to the stiffness of cortical bone. This helps decrease stress shielding around the implant. Ti also has excellent biocompatibility but poor wear resistance.

Question 38

A 68-year-old man presents with progressive clumsiness in his hands, difficulty buttoning his shirt, and a broad-based shuffling gait. Physical examination reveals a positive Hoffmann's sign. Which of the following physical examination findings is highly specific for cervical spondylotic myelopathy localized to the C5-C6 level?





Explanation

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

Question 39

A 55-year-old woman presents with progressive, painful flatfoot deformity. She has inability to perform a single-limb heel rise, and the deformity is passively correctable. MRI shows a complete rupture of the posterior tibial tendon. Which of the following surgical interventions is most appropriate?





Explanation

This patient has a Stage II adult acquired flatfoot deformity (passively correctable, unable to perform single heel rise). Standard treatment involves reconstruction, typically with an FDL tendon transfer to substitute for the PTT, combined with a medializing calcaneal osteotomy to correct the valgus hindfoot and protect the transfer.

Question 40

A 6-year-old boy sustains a Gartland type III supracondylar humerus fracture. Upon presentation, his hand is pale and pulseless. After urgent closed reduction and percutaneous pinning, the hand becomes pink and warm with brisk capillary refill, but the radial pulse remains impalpable. What is the most appropriate next step in management?





Explanation

In a 'pink, pulseless' hand after reduction of a pediatric supracondylar humerus fracture, as long as peripheral perfusion (warmth, color, capillary refill) is adequate, the current standard of care is careful clinical observation. The lack of a palpable pulse is often due to vasospasm or non-flow-limiting intimal injury.

Question 41

A 35-year-old heavy manual laborer presents with chronic wrist pain. Radiographs demonstrate radioscaphoid arthritis with preservation of the capitolunate and radiolunate joints. A diagnosis of Scapholunate Advanced Collapse (SLAC) Stage II is made. Which of the following surgical options is most appropriate to maximize postoperative grip strength for his occupation?





Explanation

For SLAC Stage II (arthritis between the scaphoid and radial styloid/scaphoid fossa), both proximal row carpectomy (PRC) and scaphoid excision with four-corner fusion (4CF) are surgical options. However, in a young, heavy manual laborer, 4CF is classically preferred over PRC because it generally preserves greater grip strength, whereas PRC carries a risk of progressive radiocapitate arthritis under heavy loading conditions.

Question 42

A 62-year-old female with a metal-on-metal total hip arthroplasty presents with groin pain and swelling. Laboratory tests show elevated serum cobalt and chromium levels. MRI reveals a large cystic mass communicating with the joint space. A revision surgery is performed. What is the classic histologic hallmark found in the periprosthetic tissue of this condition?





Explanation

The patient has Aseptic Lymphocyte-Dominated Vasculitis-Associated Lesion (ALVAL), representing a Type IV delayed hypersensitivity reaction to metal ions (cobalt and chromium). The classic histologic hallmark is a diffuse or perivascular infiltrate of T-lymphocytes, plasma cells, and macrophages containing metal debris.

Question 43

A 55-year-old male of East Asian descent presents with progressive clumsiness in his hands and broad-based gait. Lateral cervical spine radiographs show Ossification of the Posterior Longitudinal Ligament (OPLL). Which of the following defines a 'K-line negative' cervical spine, and what is its surgical implication?





Explanation

The K-line is defined as a straight line connecting the midpoints of the spinal canal at C2 and C7 on a lateral radiograph. If the OPLL mass crosses this line anteriorly to posteriorly (K-line negative), the spine is typically kyphotic or has a massive OPLL, meaning a posterior decompression (laminoplasty) will not allow the cord to drift back sufficiently. Thus, an anterior decompression or a combined anterior-posterior approach is indicated.

Question 44

A 9-year-old boy presents with a left-sided Slipped Capital Femoral Epiphysis (SCFE) and undergoes in situ single-screw fixation. Under which of the following conditions is prophylactic pinning of the contralateral, asymptomatic right hip most strongly indicated?





Explanation

Prophylactic pinning of the contralateral hip in SCFE is controversial but is universally recommended in patients with endocrine or metabolic disorders (e.g., hypothyroidism, renal osteodystrophy, growth hormone supplementation) due to the exceedingly high risk of bilateral involvement. Age at presentation (boys <10, girls <8) is also a strong indication.

Question 45

A 28-year-old male sustains a severe closed pelvic ring injury in a motorcycle collision. Radiographs demonstrate a Lateral Compression (LC) Type III fracture pattern. He is hemodynamically unstable despite a pelvic binder and massive transfusion protocol. Angiography is performed. Which vessel is statistically most likely to be the source of major arterial hemorrhage in this specific fracture pattern?





Explanation

In Lateral Compression (LC) pelvic ring injuries, the posterior pelvic ring is disrupted (e.g., sacral fracture or SI joint disruption), placing the posterior branches of the internal iliac artery at high risk. The superior gluteal artery is the most commonly injured artery in LC patterns. In contrast, Anterior Posterior Compression (APC) injuries typically injure the anterior branches (obturator and internal pudendal arteries).

Question 46

A 54-year-old poorly controlled diabetic male presents with a swollen, erythematous, and warm right foot without open ulcers. Pulses are bounding. Radiographs demonstrate periarticular fragmentation, debris, and subluxation at the tarsometatarsal joints. According to the Eichenholtz classification, what is the most appropriate initial management?





Explanation

This patient presents with Stage 1 (Developmental/Fragmentation) Charcot neuroarthropathy, characterized by warmth, erythema, bounding pulses, and radiographic fragmentation/debris. The standard of care for acute, active (Stage 1) Charcot is immobilization and offloading, typically utilizing a total contact cast (TCC). Surgery in Stage 1 carries a very high failure rate and is generally avoided unless there is severe, unstable deformity threatening the soft tissue envelope.

Question 47

A 22-year-old soccer player undergoes anterior cruciate ligament (ACL) reconstruction using a bone-patellar tendon-bone autograft. During rehabilitation, the knee lacks full extension but has normal flexion. The surgeon suspects femoral tunnel malposition. Which of the following femoral tunnel placement errors is most likely responsible for this specific clinical finding?





Explanation

If the femoral tunnel is placed too anterior (shallow) in the intercondylar notch, the distance between the femoral and tibial tunnels increases as the knee extends, causing the graft to become excessively tight in extension (resulting in an extension block) and loose in flexion. A graft placed too vertical (12 o'clock) controls anterior translation but fails to control rotational stability (positive pivot shift).

Question 48

A 16-year-old male is diagnosed with high-grade intramedullary osteosarcoma of the distal femur. Following 10 weeks of neoadjuvant multi-agent chemotherapy, he undergoes wide surgical resection. Pathological examination of the resected specimen is performed. Which of the following findings is the most significant prognostic indicator for long-term overall survival in this patient?





Explanation

In the management of osteosarcoma, the degree of tumor necrosis following neoadjuvant chemotherapy is the single most important prognostic factor for long-term survival. According to the Huvos grading system, a 'good response' is defined as >90% tumor necrosis, which correlates with significantly improved disease-free and overall survival.

Question 49

Bone morphogenetic proteins (BMPs) play a critical role in osteoinduction and fracture healing. Following the binding of BMP-2 to its transmembrane serine/threonine kinase receptor, which of the following intracellular signaling molecules is phosphorylated to translocate to the nucleus and initiate transcription of osteogenic genes?





Explanation

BMP signaling operates primarily through the SMAD pathway. When BMP binds to its serine/threonine kinase receptor, it phosphorylates receptor-regulated SMADs (specifically SMAD 1, 5, and 8). These then form a complex with the co-SMAD (SMAD 4), which translocates to the nucleus to regulate the transcription of target genes necessary for osteoblast differentiation.

Question 50

A 4-week-old female infant is diagnosed with developmental dysplasia of the hip (DDH) and placed in a Pavlik harness. Ultrasound confirms the hip is completely dislocated. After 3 weeks of strict, full-time wear, repeat ultrasound demonstrates that the hip remains persistently dislocated. What is the next best step in management?





Explanation

If a hip remains completely dislocated after 3 to 4 weeks of proper Pavlik harness treatment, the harness should be discontinued. Prolonged use of a harness on an irreducible hip leads to 'Pavlik harness disease' (excoriation/flattening of the posterior acetabulum) and increases the risk of avascular necrosis. The next step is a rigid abduction orthosis (e.g., Ilfeld or von Rosen) or proceeding directly to closed reduction and spica casting.

Question 51

A 25-year-old rugby player injures his right ring finger while grabbing an opponent's jersey. He is unable to actively flex the distal interphalangeal (DIP) joint. Radiographs show a small bony avulsion fragment volar to the proximal interphalangeal (PIP) joint. According to the Leddy-Packer classification, what type of injury is this, and what is its blood supply status?





Explanation

This is a Leddy-Packer Type II flexor digitorum profundus (FDP) avulsion. The tendon retracts to the level of the PIP joint, held there by the intact vincula longus, which preserves some blood supply to the tendon. This allows for slightly delayed repair compared to a Type I injury (tendon retracted into the palm, vincula ruptured, severely compromised blood supply requiring repair within 7-10 days). Type III involves a large bony fragment caught at the A4 pulley (DIP joint).

Question 52

During a primary total knee arthroplasty in a patient with a severe fixed varus deformity, the surgeon must perform sequential medial releases to balance the knee in extension. After releasing the deep medial collateral ligament (MCL) and removing medial tibial osteophytes, the medial compartment remains tight in extension. What is the next most appropriate anatomic structure to release?





Explanation

The classic sequence for correcting a fixed varus deformity in TKA involves releasing structures from anterior to posterior and proximal to distal. The sequence generally is: 1) Deep MCL and removal of osteophytes. 2) Posteromedial capsule and semimembranosus insertions (to release tightness in extension). 3) Superficial MCL (subperiosteal peeling off the tibia). 4) Pes anserinus (if still tight, though rarely needed). Releasing the posteromedial corner specifically helps balance the knee in extension.

Question 53

A 40-year-old male sustains a high-energy complex tibial plateau fracture involving a large, displaced posteromedial fragment (Schatzker IV). The surgeon plans a direct posteromedial approach for buttress plating. Which of the following describes the correct inter-nervous or muscular interval for this specific approach?





Explanation

The posteromedial approach to the tibial plateau utilizes the interval between the medial head of the gastrocnemius (which is retracted laterally/posteriorly along with the neurovascular bundle) and the pes anserinus / semimembranosus (which are retracted medially/anteriorly). This provides excellent direct access to the posteromedial corner of the tibia for buttress plate application.

Question 54

A 14-year-old gymnast presents with chronic low back pain that worsens with extension. Lateral lumbar radiographs reveal a Grade I spondylolisthesis at L5-S1 with a visible pars interarticularis defect. According to the Wiltse classification, which type of spondylolisthesis does this patient have?





Explanation

The Wiltse classification of spondylolisthesis is: Type I: Dysplastic (congenital abnormalities of the upper sacrum or L5 arch). Type II: Isthmic (lesion in the pars interarticularis, typical in young athletes like gymnasts). Type III: Degenerative (secondary to long-standing segmental instability). Type IV: Traumatic (fractures in areas other than the pars). Type V: Pathologic (generalized or localized bone disease). Type VI: Iatrogenic.

Question 55

A 24-year-old professional baseball pitcher presents with posterior shoulder pain during the late cocking phase of throwing. He exhibits Glenohumeral Internal Rotation Deficit (GIRD). MRI arthrogram reveals a partial articular-sided supraspinatus tendon avulsion (PASTA) and superior labral fraying. The primary pathophysiology of his 'internal impingement' involves the abnormal contact between the articular side of the rotator cuff and which of the following structures?





Explanation

Internal impingement in overhead throwing athletes occurs during the late cocking phase (maximum abduction and external rotation). In this position, the articular surface of the posterior rotator cuff (supraspinatus/infraspinatus junction) becomes pinched or rubs directly against the posterosuperior glenoid rim and labrum. This is completely distinct from classic subacromial (external) impingement, which involves the bursal surface of the cuff and the undersurface of the acromion or coracoacromial ligament.

Question 56

A 60-year-old obese female presents with a painful, progressive flatfoot deformity. Examination reveals she is unable to perform a single-leg heel rise on the affected side. The deformity is flexible and passively correctable to neutral. What is the most appropriate surgical intervention for this stage of Posterior Tibial Tendon Dysfunction (PTTD)?





Explanation

This patient has Stage II PTTD (flexible flatfoot, inability to perform a single-leg heel rise). Stage I is tenosynovitis without deformity; Stage III is a rigid/fixed deformity; Stage IV involves ankle joint arthritis/tilt. The gold standard surgical treatment for Stage II PTTD is an extra-articular bony correction (Medial Displacement Calcaneal Osteotomy) combined with a soft tissue reconstruction (FDL tendon transfer to substitute for the incompetent PTT). Triple arthrodesis is reserved for Stage III (rigid) deformity.

Question 57

In total joint arthroplasty, the use of highly cross-linked ultra-high-molecular-weight polyethylene (HXLPE) has significantly reduced volumetric wear rates. However, the radiation used to create cross-links also generates free radicals that can cause oxidative degradation. To eliminate these free radicals without compromising the fatigue strength of the polyethylene, manufacturers currently utilize which of the following techniques?





Explanation

Irradiation creates cross-links (reducing wear) but leaves free radicals (causing oxidation). Remelting eliminates free radicals but decreases the mechanical fatigue strength and fracture toughness of the polyethylene. Annealing preserves strength but leaves some free radicals. Doping the HXLPE with Vitamin E (a potent antioxidant) neutralizes the free radicals without the need for post-irradiation thermal treatment (remelting), thereby preserving the mechanical strength and fatigue resistance of the material while maintaining excellent wear properties.

Question 58

A 28-year-old male presents with a slowly enlarging, painless mass deep in the soft tissues of his right thigh. Imaging reveals a juxta-articular soft tissue mass with punctate calcifications. Core needle biopsy demonstrates a biphasic pattern of spindle cells and epithelial cells. Molecular testing reveals a t(X;18)(p11;q11) chromosomal translocation. What is the diagnosis?





Explanation

Synovial sarcoma is characterized by the t(X;18)(p11;q11) translocation, which creates the SYT-SSX fusion gene. Clinically, it often presents in young adults as a slow-growing, deep mass near a joint (though rarely intra-articular) and is one of the few soft tissue sarcomas that frequently exhibits calcifications on plain radiographs (in up to 30% of cases). It can be monophasic (spindle cells only) or biphasic (spindle and epithelial cells).

Question 59

When treating a newborn with idiopathic congenital talipes equinovarus (clubfoot) using the Ponseti method, serial manipulations and casting are performed. What is the correct anatomical sequence of deformity correction in this technique?





Explanation

The Ponseti method follows the CAVE sequence of correction: 1) Cavus (corrected first by elevating the first ray to supinate the forefoot and align it with the hindfoot), 2) Adductus, 3) Varus (adductus and varus correct simultaneously as the foot is abducted around the fixed head of the talus), 4) Equinus (corrected last, usually requiring a percutaneous Achilles tenotomy once the foot is fully abducted).

Question 60

A 65-year-old female sustains a comminuted intra-articular distal radius fracture. CT scan reveals a separate, small, displaced volar-ulnar corner fragment (volar lunate facet). If this specific fragment is not captured securely during internal fixation, the patient is at highest risk for which of the following complications?





Explanation

The volar ulnar corner of the distal radius (volar lunate facet) is a critical keystone for carpal stability because the short radiolunate ligament attaches here. Standard volar locking plates often fail to capture this small, distal fragment. If it is missed or inadequately stabilized (often requiring fragment-specific fixation like a hook plate or wire), the lunate—and consequently the entire carpus—will subluxate or dislocate volarly.

Previous ChapterArab Board Orthopedic Exam: Skeletal Dysplasias MCQs Next Chapter Arab Orthopaedic Board MCQs - Part 3
Clinic OS
Medically Verified Content by
Prof. Clinic OS
Consultant Orthopedic & Spine Surgeon
Chapter Index
    Back to Master Guide