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Updated Orthopedic Review | Dr Hutaif General Orthopedi -...

Orthopedic With Answers Review | Dr Hutaif General Orth -...

23 Apr 2026 107 min read 131 Views
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Key Takeaway

In this comprehensive guide, we discuss everything you need to know about ORTHOPEDIC MCQS WITH ANSWERS ONLINE TRAUMA 06. When a 35-year-old man sustained an injury, the most appropriate indication for replantation is a complete amputation of the hand at the wrist level. Forearm amputations with a warm ischemia time under 6 hours are also suitable. Replantation is generally less indicated for single-digit amputations (excluding the thumb) or very distal finger injuries where functional benefit is minimal.

Orthopedic With Answers Review | Dr Hutaif General Orth -...

Comprehensive 100-Question Exam


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Question 1

A 32-year-old male sustains a displaced basicervical femoral neck fracture. Which of the following fixation constructs is associated with the highest biomechanical stability for this specific fracture pattern?





Explanation

Basicervical femoral neck fractures behave similarly to intertrochanteric fractures and are highly unstable. Biomechanical studies have shown that a sliding hip screw (DHS) provides superior stability compared to multiple cancellous screws for basicervical patterns. Adding a derotational screw improves rotational stability and mitigates rotation during lag screw insertion.

Question 2

An overweight 13-year-old boy presents with right thigh pain and an obligatory external rotation of the hip during active hip flexion. Radiographs confirm a mild stable slipped capital femoral epiphysis (SCFE). During in situ single-screw fixation, where should the screw ideally be placed within the epiphysis?





Explanation

The ideal starting point for in situ pinning of a SCFE is on the anterior neck, aiming for the center-center position of the epiphysis on both the anteroposterior and lateral radiographic views. This central placement minimizes the risk of joint penetration and avoids the lateral epiphyseal vessels, reducing the risk of avascular necrosis.

Question 3

Following an anterior cruciate ligament (ACL) reconstruction using a bone-patellar tendon-bone autograft, a patient develops a 'cyclops lesion'. Which of the following is the most characteristic clinical finding associated with this complication?





Explanation

A 'cyclops lesion' is a localized form of anterior arthrofibrosis (a fibrovascular nodule) that typically forms anterior to the ACL graft in the intercondylar notch. Because of its location, it mechanically blocks the tibia from achieving full extension, leading to a hallmark loss of terminal knee extension.

Question 4

Which of the following stages of fracture healing is most reliant on the presence of transforming growth factor-beta (TGF-beta) and platelet-derived growth factor (PDGF) released from degranulating platelets?





Explanation

Following a fracture, hematoma formation and the inflammatory phase occur first. Degranulating platelets within the fracture hematoma release key cytokines, including PDGF and TGF-beta, which recruit mesenchymal stem cells and initiate the early cascade of the inflammatory phase of bone healing.

Question 5

In total hip arthroplasty (THA), utilizing the posterior approach carries a higher risk of postoperative dislocation compared to the direct anterior approach. Which of the following anatomical structures is primarily repaired to mitigate this risk?





Explanation

The posterior approach to the hip involves releasing the short external rotators (piriformis, superior gemellus, obturator internus, inferior gemellus) and the posterior capsule. An enhanced posterior soft tissue repair, which involves suturing these structures back to the greater trochanter, significantly reduces the postoperative dislocation rate.

Question 6

A 45-year-old male complains of neck pain radiating down his right arm, with weakness in elbow flexion and wrist extension. His brachioradialis reflex is diminished. Which cervical nerve root is most likely compressed?





Explanation

C6 radiculopathy typically presents with weakness in wrist extension (extensor carpi radialis longus/brevis) and elbow flexion (biceps/brachioradialis), with sensory changes in the thumb and radial aspect of the forearm. The brachioradialis reflex is primarily mediated by the C6 nerve root.

Question 7

A 30-year-old manual laborer presents with progressive dorsal wrist pain. Radiographs reveal sclerosis and fragmentation of the lunate, consistent with Lichtman Stage IIIA Kienböck's disease, and ulnar negative variance. Which of the following surgical interventions is most appropriate?





Explanation

In Lichtman Stage IIIA Kienböck's disease (lunate collapse but no fixed scaphoid rotation or carpal arthritis) with ulnar negative variance, joint-leveling procedures such as a radial shortening osteotomy are indicated. This shifts mechanical load off the lunate and onto the ulnocarpal joint.

Question 8

A 55-year-old patient with long-standing, poorly controlled diabetes presents with a warm, swollen, erythematous left foot. Radiographs show fragmentation and periarticular debris at the tarsometatarsal joints. Laboratory markers (WBC, ESR, CRP) are minimally elevated. What is the most appropriate initial management?





Explanation

The clinical presentation is classic for acute Eichenholtz Stage I Charcot arthropathy (fragmentation). The initial treatment of choice is strict immobilization and offloading, most effectively achieved with total contact casting and non-weight-bearing. Surgery is contraindicated during the acute inflammatory phase unless there is severe impending ulceration or instability that cannot be braced.

Question 9

Which of the following radiographic parameters is the most critical to restore to prevent long-term radiocarpal arthrosis following surgical fixation of an intra-articular distal radius fracture?





Explanation

While restoring extra-articular alignment parameters is important for kinematics, restoring articular congruity (minimizing step-off to less than 1-2 mm) is the single most critical factor in preventing the development of post-traumatic radiocarpal arthrosis after an intra-articular fracture.

Question 10

A 6-month-old female is diagnosed with developmental dysplasia of the hip (DDH) after failing Pavlik harness treatment. A closed reduction and spica casting are planned. To minimize the risk of avascular necrosis (AVN) of the femoral head during casting, what is the safest position for the hip?





Explanation

Immobilizing the hip in extreme abduction (the classic 'frog-leg' position) dramatically increases the risk of AVN, particularly of the posterosuperior aspect of the femoral head, due to compression of the medial circumflex femoral artery branches. The 'safe zone' of Ramsey requires casting the hip in 90-100 degrees of flexion and moderate abduction (typically <60 degrees).

Question 11

A 15-year-old male presents with persistent knee pain. Radiographs reveal a mixed lytic and sclerotic lesion in the distal femoral metaphysis with a 'sunburst' periosteal reaction. Biopsy confirms high-grade intramedullary osteosarcoma. What is the standard treatment protocol?





Explanation

The standard of care for high-grade classic intramedullary osteosarcoma involves multi-agent neoadjuvant chemotherapy, followed by limb-salvage surgery (wide surgical resection), and then adjuvant chemotherapy. Radiation therapy is rarely used as osteosarcoma is highly radioresistant.

Question 12

A 65-year-old female presents with neurogenic claudication secondary to lumbar spinal stenosis. She states her leg pain improves when she leans forward on a shopping cart. Which of the following anatomical changes explains this phenomenon?





Explanation

Lumbar flexion increases the anterior-posterior diameter of the spinal canal and the cross-sectional area of the neural foramina. It stretches the ligamentum flavum, reducing its inward buckling into the spinal canal, thereby temporarily relieving mechanical compression on the cauda equina and nerve roots.

Question 13

Galvanic corrosion in orthopedic implants is most likely to occur when which of the following conditions is met?





Explanation

Galvanic corrosion occurs when two dissimilar metals (such as stainless steel and titanium) are in physical contact within an electrolytic solution (like bodily fluids). The difference in their electrochemical potentials drives an electron transfer, causing the more anodic metal to corrode.

Question 14

A 40-year-old patient is involved in an MVC and sustains an anteroposterior compression type III (APC-III) pelvic ring injury. In the trauma bay, the patient is hypotensive and tachycardic. A pelvic binder is applied. What is the correct anatomical landmark for the placement of the pelvic binder to effectively reduce pelvic volume?





Explanation

Pelvic binders must be centered over the greater trochanters (at the level of the symphysis pubis) to effectively compress the pelvic ring, internally rotate the hemi-pelves, and reduce the intrapelvic volume. Placement over the iliac crests is a common error and can worsen the rotational deformity.

Question 15

A 22-year-old rugby player has recurrent anterior shoulder dislocations. Preoperative imaging reveals an anterior glenoid bone loss of 25%. Which of the following surgical procedures is the most appropriate definitive management for this patient?





Explanation

In the setting of significant anterior glenoid bone loss (typically >20-25%), soft tissue stabilization alone (e.g., Bankart repair) has unacceptably high failure rates. A bone block procedure, such as the Latarjet procedure (transfer of the coracoid process with the attached conjoint tendon to the anterior glenoid), is the gold standard for restoring stability.

Question 16

During a total knee arthroplasty, after making the standard bone cuts, the surgeon notices that the knee is tight in flexion but symmetric and well-balanced in extension. Which of the following adjustments is most appropriate to balance the knee?





Explanation

A knee that is tight in flexion but balanced in extension has an isolated tight flexion gap. Interventions to increase the flexion gap without altering the extension gap include increasing the posterior slope of the tibial cut or downsizing the femoral component (which decreases the AP dimension). Option 1 directly addresses the tight flexion gap. Option 3 is incorrect because using a thicker insert would tighten the extension gap.

Question 17

Following a Zone II flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) repair, a patient undergoes early active motion rehabilitation. At 6 weeks post-op, the patient demonstrates an inability to actively flex the distal interphalangeal (DIP) joint, despite full passive range of motion. What is the most likely cause?





Explanation

The inability to actively flex the DIP joint with fully preserved passive motion indicates a mechanical failure of the FDP tendon. Given that the patient is moving the finger but specifically lacks active DIP flexion, the most likely diagnosis is an intact FDS repair with a ruptured FDP repair.

Question 18

A 28-year-old male sustains a closed tibia fracture and undergoes intramedullary nailing. Six hours postoperatively, he requires increasing doses of opioids and complains of severe leg pain exacerbated by passive stretch of his toes. Compartment pressure monitoring reveals an anterior compartment pressure of 45 mmHg and a diastolic blood pressure of 60 mmHg. What is the delta pressure, and what is the indicated management?





Explanation

Delta pressure is calculated as Diastolic Blood Pressure minus Compartment Pressure. Here, 60 - 45 = 15 mmHg. A delta pressure of < 30 mmHg represents inadequate tissue perfusion and is the clinical threshold for diagnosing acute compartment syndrome, necessitating emergent four-compartment fasciotomy.

Question 19

In the Ponseti method for the treatment of idiopathic clubfoot, the sequence of correction is paramount. Which of the following components of the deformity is corrected first?





Explanation

The Ponseti method follows a strict sequence of correction summarized by the acronym CAVE: Cavus, Adductus, Varus, Equinus. The first step is to correct the cavus deformity by supinating the forefoot to align it with the hindfoot, effectively elevating the first ray.

Question 20

A 68-year-old male presents with severe back pain and generalized fatigue. Laboratory studies reveal hypercalcemia, anemia, and an elevated total protein with a monoclonal spike on serum protein electrophoresis (SPEP). Radiographs demonstrate multiple 'punched-out' lytic lesions in the skull and vertebral bodies. Which of the following is the most definitive diagnostic test for the underlying condition?





Explanation

The patient's presentation is classic for Multiple Myeloma (CRAB criteria: hyperCalcemia, Renal involvement, Anemia, Bone lesions). While SPEP, urine immunofixation, and skeletal surveys are crucial in the workup, the definitive diagnostic test is a bone marrow aspirate and biopsy demonstrating >10% clonal plasma cells.

Question 21

An 11-year-old boy presents with a painful mass in his diaphyseal femur. Biopsy reveals small round blue cells. Cytogenetic analysis is pending. Which of the following chromosomal translocations is most characteristic of this lesion?





Explanation

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

Question 22

In total joint arthroplasty, which of the following wear mechanisms is primarily responsible for the generation of submicron polyethylene particles that lead to macrophage-mediated osteolysis?





Explanation

Adhesive wear is the primary mechanism generating submicron ultra-high-molecular-weight polyethylene (UHMWPE) wear debris in total joint arthroplasty, which initiates the macrophage-mediated osteolytic cascade.

Question 23

A 28-year-old carpenter sustains a laceration over the palmar aspect of his proximal phalanx. Examination reveals an inability to flex the PIP and DIP joints of the index finger. In which flexor tendon zone did this injury occur?





Explanation

The laceration is over the proximal phalanx, which corresponds to Zone II (historically termed 'No Man's Land'). This zone contains both the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) tendons within the tight fibro-osseous sheath.

Question 24

During the physical examination of a 65-year-old man with neck pain and gait clumsiness, the examiner flicks the distal phalanx of the middle finger, resulting in reflex flexion of the thumb and index finger. This clinical sign is mediated by which of the following nerve roots?





Explanation

The Hoffmann sign indicates an upper motor neuron lesion in the cervical spine (cervical myelopathy). The reflex arc itself is mediated via the C8 nerve root, which innervates the long finger flexors.

Question 25

A 4-year-old girl is evaluated for short stature, frontal bossing, and rhizomelic shortening of the limbs. Radiographs show narrowing of the interpedicular distances in the lumbar spine. A mutation in which of the following genes is the definitive cause?





Explanation

The clinical and radiographic presentation is classic for achondroplasia. It is caused by an activating mutation in the Fibroblast Growth Factor Receptor 3 (FGFR3) gene, leading to inhibition of chondrocyte proliferation in the proliferative zone of the physis.

Question 26

In a cruciate-retaining (CR) total knee arthroplasty, the posterior cruciate ligament (PCL) is preserved. During normal knee flexion, what is the primary biomechanical function of an intact PCL?





Explanation

The PCL functions to facilitate posterior femoral rollback during knee flexion. This rollback increases maximal flexion by preventing early posterior impingement and improves the mechanical advantage of the extensor mechanism.

Question 27

A 45-year-old motorcyclist sustains a closed pelvic ring injury. Clinically, there is a large, fluctuant swelling over the greater trochanter with ecchymosis. Aspiration yields serosanguinous fluid. What is the most appropriate initial management of this specific soft tissue lesion?





Explanation

The patient has a Morel-Lavallee lesion, a closed degloving injury where skin and subcutaneous fat are separated from the underlying fascia. Initial management of acute lesions often involves percutaneous drainage and firm compression to obliterate the dead space and prevent pseudocyst formation.

Question 28

A 22-year-old elite baseball pitcher complains of posterior shoulder pain during the late cocking phase of throwing. MRI shows partial-thickness articular-sided tearing of the posterior supraspinatus and anterior infraspinatus, along with posterosuperior labral fraying. What is the primary pathomechanism?





Explanation

Internal impingement occurs in overhead athletes during maximal abduction and external rotation (late cocking phase). The greater tuberosity abuts the posterosuperior glenoid, pinching the articular side of the rotator cuff and the posterosuperior labrum.

Question 29

Which Bone Morphogenetic Protein (BMP) is FDA approved as an alternative to autograft for anterior lumbar interbody fusion (ALIF)?





Explanation

Recombinant human BMP-2 (rhBMP-2) is FDA approved for single-level anterior lumbar interbody fusion (ALIF) within a specific carrier. BMP-7 (also known as OP-1) was previously approved under a humanitarian device exemption for recalcitrant long bone nonunions.

Question 30

A 35-year-old male undergoes surgical repair of an acute midsubstance Achilles tendon rupture using a percutaneous or limited open technique. To avoid capturing the sural nerve during the proximal aspect of the repair, the surgeon must be particularly cautious on which aspect of the tendon?





Explanation

The sural nerve crosses from medial to lateral and runs in close proximity to the anterolateral border of the Achilles tendon in its middle and proximal third. Suture passes in this region carry the highest risk of iatrogenic nerve entrapment.

Question 31

A 28-year-old man sustains an anterior shoulder dislocation. Post-reduction, he has weakness in shoulder abduction and decreased sensation over the lateral deltoid. EMG confirms an isolated axillary nerve injury. Through which anatomical space does this nerve normally exit the axilla?





Explanation

The axillary nerve and posterior circumflex humeral artery exit the axilla posteriorly through the quadrangular space. The boundaries are the teres minor (superior), teres major (inferior), long head of the triceps (medial), and the surgical neck of the humerus (lateral).

Question 32

A 6-year-old boy presents with a painless limp. Radiographs reveal sclerosis and fragmentation of the proximal femoral epiphysis. According to the Herring lateral pillar classification, which of the following describes a Group B hip?





Explanation

The Herring lateral pillar classification for Legg-Calve-Perthes disease evaluates the height of the lateral portion of the capital femoral epiphysis on an AP radiograph. Group A has 100% height maintained, Group B maintains >50% height, and Group C has <50% height maintained.

Question 33

During total hip arthroplasty, increasing the femoral offset without changing the leg length will have which of the following biomechanical effects?





Explanation

Increasing femoral offset moves the femur further from the center of rotation, increasing the moment arm (mechanical advantage) of the abductor muscles. This decreases the force required by the abductors to maintain a level pelvis, thus decreasing the joint reactive force.

Question 34

A 24-year-old male complains of severe dull pain in his thoracic spine that is not reliably relieved by NSAIDs. CT scan shows a 2.5 cm radiolucent nidus with posterior element expansion. Histology shows interlacing trabeculae of woven bone lined by prominent osteoblasts. What is the most likely diagnosis?





Explanation

Osteoblastoma is histologically identical to osteoid osteoma but is clinically differentiated by a nidus size >2 cm, less reliable response to NSAIDs, and progressive growth. It frequently involves the posterior elements of the spine.

Question 35

A patient with severe carpal tunnel syndrome exhibits profound thenar atrophy. Which of the following muscles is primarily innervated by the recurrent motor branch of the median nerve and is expected to be most atrophied?





Explanation

The recurrent motor branch of the median nerve innervates the Opponens pollicis, Abductor pollicis brevis, and the superficial head of the Flexor pollicis brevis. The adductor pollicis and the deep head of the flexor pollicis brevis are typically innervated by the ulnar nerve.

Question 36

A 21-year-old football player sustains a valgus blow to the knee. Exam reveals medial joint line tenderness and 5 mm of opening to valgus stress at 30 degrees of flexion with a firm endpoint. Valgus stress at 0 degrees is stable. What is the severity of the injury?





Explanation

Opening to valgus at 30 degrees with a firm endpoint indicates a Grade II sprain (partial tear) of the superficial medial collateral ligament (sMCL), which is the primary restraint to valgus stress at 30 degrees of flexion. Complete tears (Grade III) lack a firm endpoint.

Question 37

A total hip arthroplasty with a cobalt-chromium (CoCr) femoral head and a titanium alloy stem is revised for aseptic loosening. Black debris is noted at the modular head-neck junction. Which type of corrosion initiates the mechanically assisted crevice corrosion (MACC) at this modular interface?





Explanation

Fretting corrosion initiates mechanically assisted crevice corrosion (MACC) at the modular head-neck junction (trunnionosis) of a THA. Fretting (micromotion) continuously breaks the protective oxide passivation layer, allowing subsequent crevice and galvanic corrosion to proceed.

Question 38

In a patient with a tibia fracture and suspected compartment syndrome, which of the following clinical findings is classically considered the earliest and most sensitive indicator of increased intracompartmental pressure?





Explanation

Pain out of proportion to the apparent injury, specifically exacerbated by passive stretch of the muscles in the involved compartment, is the earliest and most sensitive clinical sign of acute compartment syndrome. Pulselessness, pallor, and paralysis are late, often irreversible signs.

Question 39

According to the Denis three-column theory of the spine, the middle column comprises which of the following structures?





Explanation

In the Denis three-column concept, the middle column consists of the posterior half of the vertebral body, posterior half of the annulus fibrosus, and the posterior longitudinal ligament (PLL). A burst fracture involves failure of both the anterior and middle columns.

Question 40

A 26-year-old athlete sustains a midfoot sprain. Weight-bearing radiographs show a 3 mm widening between the base of the 1st and 2nd metatarsals. The primary structural ligament that has been compromised connects which two bones?





Explanation

The Lisfranc ligament is an intra-articular interosseous ligament that connects the lateral aspect of the medial cuneiform to the medial base of the second metatarsal. There is notably no direct ligamentous connection between the bases of the 1st and 2nd metatarsals.

Question 41

A 65-year-old man undergoes revision total hip arthroplasty where a cobalt-chromium femoral head is placed onto a titanium alloy femoral stem. Which of the following types of corrosion is most likely to occur at the head-neck junction?





Explanation

Galvanic corrosion occurs when two dissimilar metals (such as cobalt-chromium and titanium alloy) are placed in physical contact within an electrolytic solution like body fluid. The less noble metal undergoes accelerated corrosion. Fretting corrosion can also occur at modular junctions due to micromotion, but the presence of dissimilar metals specifically defines galvanic corrosion.

Question 42

During an anterior cruciate ligament (ACL) reconstruction, the surgeon identifies the two bundles of the native ACL. When does the posterolateral (PL) bundle experience its maximum tension?





Explanation

The ACL consists of the anteromedial (AM) and posterolateral (PL) bundles. The AM bundle tightens in flexion and is primarily responsible for anterior-posterior stability. The PL bundle is tightest in extension and provides critical rotational stability to the knee.

Question 43

In a patient with a high radial nerve palsy, which of the following is the most standard tendon transfer utilized to restore wrist extension?





Explanation

The classic and most reliable tendon transfer to restore wrist extension in a radial nerve palsy is transferring the Pronator Teres (PT) to the Extensor Carpi Radialis Brevis (ECRB). The ECRB is chosen over the ECRL because of its more central insertion, which limits radial deviation during wrist extension.

Question 44

A 68-year-old man presents with progressive clumsiness in his hands and difficulty with fine motor tasks. Physical examination reveals a positive Hoffmann sign bilaterally. This reflex is elicited by:





Explanation

A positive Hoffmann sign indicates an upper motor neuron lesion (such as cervical spondylotic myelopathy) and is elicited by flicking the volar surface of the distal phalanx of the middle finger. A positive response is a reflex flexion of the thumb and/or index finger.

Question 45

A 72-year-old woman presents with severe back pain. Laboratory testing shows anemia, hypercalcemia, and renal insufficiency. Radiographs reveal multiple punched-out lytic lesions in her skull and pelvis. Which of the following laboratory findings is most specific for confirming her likely diagnosis?





Explanation

The patient's presentation of back pain, anemia, hypercalcemia, renal issues, and lytic bone lesions is highly characteristic of multiple myeloma (CRAB criteria). A monoclonal spike (M-protein) on Serum Protein Electrophoresis (SPEP) or Urine Protein Electrophoresis (UPEP) is a specific diagnostic hallmark.

Question 46

Which of the following bearing surface combinations in total hip arthroplasty demonstrates the lowest linear and volumetric wear rates in laboratory simulator studies?





Explanation

Ceramic-on-ceramic bearing surfaces have the lowest linear and volumetric wear rates of all combinations due to high hardness, scratch resistance, and excellent wettability. However, they carry specific risks, such as squeaking and catastrophic brittle fracture.

Question 47

A 55-year-old woman presents with medial ankle pain and a progressive flatfoot deformity. She is unable to perform a single-leg heel raise on the affected side. Radiographs show uncovering of the talonavicular joint. This condition is primarily due to dysfunction of which tendon?





Explanation

Adult acquired flatfoot deformity is most commonly caused by posterior tibial tendon dysfunction (PTTD). The posterior tibial tendon acts as the primary dynamic stabilizer of the medial longitudinal arch, and its failure results in the inability to perform a single-leg heel raise, leading to hindfoot valgus and forefoot abduction.

Question 48

Bone morphogenetic proteins (BMPs) induce bone formation primarily through which of the following mechanisms?





Explanation

BMPs act via osteoinduction, which is the process of stimulating undifferentiated mesenchymal stem cells to differentiate into osteoprogenitor cells and eventually osteoblasts. Osteoconduction provides a scaffold, while osteogenesis requires the transfer of live cells.

Question 49

Which zone of the meniscus has the best potential for healing following surgical repair?





Explanation

The red-red zone is the peripheral outer third of the meniscus, which receives abundant vascularity from the perimeniscal capillary plexus. This robust blood supply provides the highest healing potential for meniscal repairs.

Question 50

A 45-year-old cyclist complains of numbness in his ring and small fingers after long rides. Examination reveals weakness in finger abduction and adduction but normal wrist flexion. Tinel's sign is positive at the wrist but negative at the elbow. Where is the most likely site of compression?





Explanation

Cyclist's palsy often involves compression of the ulnar nerve at Guyon's canal (ulnar tunnel) in the wrist. Symptoms include intrinsic muscle weakness and sensory deficits in the ulnar digits. Flexor carpi ulnaris (FCU) function is spared because its innervation branches off proximal to the wrist.

Question 51

A 42-year-old man presents to the emergency department with severe lower back pain, bilateral sciatica, and saddle anesthesia. He reports difficulty initiating urination. Which of the following is the most appropriate next step in management?





Explanation

The patient exhibits classic symptoms of Cauda Equina Syndrome (CES). A post-void residual (PVR) ultrasound is a rapid test to assess for urinary retention, and an emergent MRI is strictly required to confirm the diagnosis prior to urgent surgical decompression.

Question 52

A 13-year-old obese boy presents with left knee pain and a limp for 3 weeks. Examination reveals limited internal rotation of the left hip. When the hip is flexed, it obligatorily externally rotates. Radiographs show a widening of the left proximal femoral physis. What is the most appropriate definitive treatment?





Explanation

Slipped Capital Femoral Epiphysis (SCFE) frequently presents with thigh or knee pain and obligate external rotation upon hip flexion. The gold standard treatment is in situ stabilization with a single cannulated screw to prevent further slip without increasing the risk of avascular necrosis via reduction maneuvers.

Question 53

A 30-year-old man sustains a closed tibia fracture and develops severe pain out of proportion to the injury. Which of the following physical examination findings is considered the earliest and most sensitive clinical sign of acute compartment syndrome?





Explanation

Pain with passive stretch of the muscles in the affected compartment is typically the earliest clinical sign of acute compartment syndrome. Pulselessness, pallor, and paralysis are very late and ominous signs indicating irreversible ischemic damage.

Question 54

A 35-year-old woman presents with knee pain. Radiographs reveal an eccentric, lytic, epiphyseal lesion in the proximal tibia that extends to the subchondral bone without a sclerotic margin. What is the most likely diagnosis?





Explanation

Giant cell tumors (GCT) of bone classically occur in skeletally mature patients (usually 20-40 years old) and present as eccentric, lytic, epiphyseal/metaphyseal lesions that uniquely extend right up to the subchondral bone plate without a sclerotic rim.

Question 55

Secondary fracture healing with callus formation is typically seen with which of the following fixation methods?





Explanation

Intramedullary nailing provides 'relative' stability rather than absolute rigid stability. This allows for micromotion at the fracture site, which promotes secondary (endochondral) bone healing characterized by callus formation. Compression plating and lag screws achieve absolute stability, resulting in primary (intramembranous) bone healing.

Question 56

Which muscle of the rotator cuff is primarily responsible for internal rotation of the humerus?





Explanation

The subscapularis inserts onto the lesser tuberosity of the humerus and is the primary internal rotator of the shoulder among the rotator cuff muscles. The infraspinatus and teres minor are external rotators, and the supraspinatus initiates abduction.

Question 57

A 22-year-old man falls onto an outstretched hand and has pain in the anatomic snuffbox. Initial radiographs are negative for a fracture. What is the most appropriate initial management?





Explanation

A patient with anatomic snuffbox tenderness but negative initial radiographs should be clinically presumed to have an occult scaphoid fracture. The standard of care is immobilization in a thumb spica splint or cast and re-evaluation with repeat radiographs in 10-14 days, or alternatively obtaining an acute MRI.

Question 58

According to the Musculoskeletal Infection Society (MSIS) criteria, which of the following is considered a major criterion for the definitive diagnosis of a periprosthetic joint infection (PJI)?





Explanation

The major criteria for definitive periprosthetic joint infection (PJI) are: 1) Two positive periprosthetic cultures with phenotypically identical organisms, or 2) A sinus tract communicating with the joint. The other options are considered minor criteria.

Question 59

What is the predominant type of collagen found in healthy adult articular cartilage?





Explanation

Type II collagen makes up 90-95% of the collagen found in normal, healthy articular (hyaline) cartilage. Type I collagen is predominant in bone, tendon, meniscus, and fibrocartilage (which forms after cartilage injury).

Question 60

A 25-year-old football player sustains a hyperplantarflexion injury to his foot. Radiographs show widening of the space between the 1st and 2nd metatarsal bases. The Lisfranc ligament connects which two structures?





Explanation

The Lisfranc ligament is an interosseous ligament that spans from the lateral aspect of the medial cuneiform to the medial aspect of the base of the second metatarsal. It is critical for the stability of the midfoot arch, and its rupture leads to a classic Lisfranc fracture-dislocation.

Question 61

A 40-year-old male presents with severe neck pain and bilateral upper extremity weakness after a diving accident. Lateral radiographs show an anterior translation of C5 on C6 by 60%. Which of the following is the most appropriate next step in management for this awake, alert, and cooperative patient?





Explanation

In an awake, alert, and cooperative patient with a cervical facet dislocation and neurologic deficit, urgent closed reduction using cranial tongs is indicated. MRI is not required prior to closed reduction in a cooperative patient who can participate in serial neurologic exams. MRI is required if the patient is unexaminable (e.g., comatose) or fails closed reduction attempts, to evaluate for an extruded disc.

Question 62

A 35-year-old male laborer presents with chronic, progressive wrist pain and stiffness. Radiographs reveal a scaphoid nonunion with radioscaphoid arthritis and capitolunate arthritis, but the radiolunate joint is spared. What is the most appropriate surgical treatment?





Explanation

The patient has Scaphoid Nonunion Advanced Collapse (SNAC) stage III (involvement of the capitolunate joint). Proximal row carpectomy (PRC) is contraindicated in the presence of capitate arthritis, because the capitate acts as the new articular surface in the lunate fossa. Scaphoid excision and four-corner fusion is the treatment of choice when the radiolunate joint is preserved but the capitolunate joint is arthritic.

Question 63

Which of the following best describes the biological process of 'intrinsic' healing in a primarily repaired Zone II flexor tendon?





Explanation

Flexor tendon healing occurs via both intrinsic and extrinsic mechanisms. Intrinsic healing relies on the proliferation and migration of tenocytes from the epitenon and endotenon within the tendon itself, nourished heavily by synovial fluid diffusion. Extrinsic healing relies on cells and vascular ingrowth from the surrounding sheath, which forms adhesions. Modern early active motion protocols favor intrinsic healing to minimize adhesions.

Question 64

A 24-year-old football player undergoes forceful plantarflexion of the foot while another player falls on his heel. He presents with midfoot pain and swelling. Weight-bearing radiographs show a 2 mm widening between the base of the first and second metatarsals. What is the anatomic origin and insertion of the principal ligament most likely injured?





Explanation

The Lisfranc ligament is an interosseous ligament that connects the lateral aspect of the medial cuneiform to the medial aspect of the base of the second metatarsal. It is critical for midfoot stability. Injury often occurs via axial loading on a plantarflexed foot.

Question 65

A 55-year-old poorly controlled diabetic male presents with a red, hot, swollen, and painless left foot. Radiographs show joint fragmentation, periarticular debris, and subluxation of the tarsometatarsal joints. Which stage of the Eichenholtz classification does this represent, and what is the primary pathophysiological driver?





Explanation

The patient is in Eichenholtz Stage 1 (Development/Fragmentation), characterized by acute inflammation, joint laxity, subluxation, and bony fragmentation. The pathogenesis involves autonomic neuropathy leading to loss of sympathetic tone, resulting in bounding pulses, hyperemia, and active bone resorption (neurovascular theory), combined with repetitive microtrauma due to loss of protective sensation (neurotraumatic theory).

Question 66

In total hip arthroplasty, which bearing surface combination is uniquely associated with the phenomenon of 'stripe wear' and potential squeaking?





Explanation

Ceramic-on-ceramic (CoC) bearings have excellent overall wear properties but are associated with specific complications, including squeaking and 'stripe wear'. Stripe wear occurs due to edge loading or microseparation during the swing phase, where the femoral head contacts the edge of the ceramic liner, leaving a narrow track of wear.

Question 67

During normal native knee flexion, the femoral condyles exhibit posterior rollback. In a posterior-stabilized (PS) total knee arthroplasty, which of the following mechanical features substitutes for the posterior cruciate ligament (PCL) to induce this posterior rollback?





Explanation

In a posterior-stabilized (PS) total knee arthroplasty, the PCL is excised. Posterior femoral rollback during flexion is achieved mechanically by the engagement of the femoral cam against the tibial polyethylene post. This prevents anterior translation of the femur on the tibia during deep flexion, mimicking the function of the native PCL.

Question 68

A 65-year-old man presents with dull aching pain in his right thigh and an increasing hat size. Radiographs of his femur demonstrate cortical thickening, increased trabecular markings, and a 'blade of grass' lucency. A bone biopsy would most likely reveal which of the following cellular abnormalities?





Explanation

The clinical picture is classic for Paget's disease of bone (osteitis deformans). The primary cellular defect is hyperactive, enlarged, multinucleated osteoclasts (sometimes with up to 100 nuclei per cell). Ultrastructural studies often show paramyxovirus-like (e.g., measles, RSV) inclusion bodies within both the cytoplasm and nuclei of these osteoclasts, pointing to a possible viral etiology.

Question 69

Articular cartilage exhibits highly predictable viscoelastic properties. When a constant compressive load is applied to cartilage, it deforms rapidly at first, followed by a slow, progressive increase in deformation until an equilibrium is reached. This time-dependent biomechanical phenomenon is known as:





Explanation

'Creep' is defined as the progressive deformation of a viscoelastic material under a constant load over time. In articular cartilage, this is primarily due to the exudation of interstitial fluid from the extracellular matrix. 'Stress relaxation', by contrast, is the decrease in stress over time when a material is held at a constant strain (constant deformation).

Question 70

Which type of corrosion occurs in modular junctions of orthopedic implants, such as the head-neck taper of a total hip arthroplasty, primarily due to micromotion that mechanically disrupts the protective passive oxide layer?





Explanation

Fretting corrosion occurs at contact sites between materials under load subject to minute relative motion (micromotion). This micromotion constantly disrupts the protective passive oxide film on the metal surface, exposing the underlying metal and leading to accelerated localized corrosion. This is the primary mechanism of trunnionosis in the modular head-neck taper of a THA.

Question 71

A 30-year-old female is diagnosed with a giant cell tumor (GCT) of the distal femur. Because the tumor is marginally resectable, she is treated with denosumab to downstage the lesion. Denosumab exerts its therapeutic effect by binding directly to which of the following targets?





Explanation

Denosumab is a fully human monoclonal antibody that binds directly to RANKL (Receptor Activator of Nuclear factor Kappa-B Ligand), thereby preventing it from interacting with the RANK receptor on the surface of osteoclasts and their precursors. In GCT, neoplastic stromal cells overexpress RANKL, recruiting destructive osteoclast-like giant cells. Denosumab halts this osteolysis.

Question 72

A 13-year-old obese boy presents with right groin pain and an antalgic gait. Radiographs reveal a slipped capital femoral epiphysis (SCFE) of the right hip. The left hip is radiographically normal. Which of the following is the most widely accepted absolute indication for prophylactic in situ pinning of the contralateral, asymptomatic hip?





Explanation

Prophylactic pinning of the contralateral hip in SCFE is debated for idiopathic cases but is highly recommended (considered an absolute indication by most authorities) in patients with endocrine disorders (e.g., hypothyroidism, renal osteodystrophy, panhypopituitarism), previous radiation therapy, or very young age at presentation (<10 years), as these patients have an exceptionally high risk of a contralateral slip.

Question 73

A 6-week-old infant with developmental dysplasia of the hip (DDH) is being treated with a Pavlik harness. During a follow-up visit, the parents report that the infant is no longer kicking the treated leg. Examination reveals an inability to actively extend the knee, while foot and ankle movements are intact. Which nerve is most likely compressed, and what aspect of the harness positioning is responsible?





Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment, typically caused by hyperflexion of the hip (anterior straps pulled too tightly). It presents as an inability to actively extend the knee due to transient loss of quadriceps function. The appropriate management is to loosen the anterior straps or temporarily discontinue the harness to allow nerve recovery.

Question 74

According to the Young-Burgess classification, an Anteroposterior Compression Type II (APC-II) pelvic ring injury is characterized by rupture of the anterior sacroiliac ligaments while maintaining the integrity of which specific posterior structures?





Explanation

An APC-II injury involves pubic symphyseal diastasis and rupture of the anterior sacroiliac ligaments, sacrotuberous, and sacrospinous ligaments. The strong posterior sacroiliac ligaments remain intact, providing vertical stability but resulting in rotational instability ('open book' pelvis). An APC-III injury involves disruption of BOTH anterior and posterior SI ligaments, resulting in both rotational and vertical instability.

Question 75

A 45-year-old male sustains a posteromedial shear fracture of the tibial plateau (Schatzker IV). To appropriately buttress this fracture fragment, a posteromedial surgical approach is planned. Between which two anatomical structures is the primary internervous/intermuscular interval for this approach?





Explanation

The posteromedial approach to the tibial plateau utilizes the interval between the pes anserinus and semimembranosus (anteriorly) and the medial head of the gastrocnemius (posteriorly). This retracts the neurovascular bundle posteriorly with the gastrocnemius, allowing safe access to the posteromedial cortex for the placement of an anti-glide or buttress plate.

Question 76

Following an autograft anterior cruciate ligament (ACL) reconstruction, the graft undergoes a biological process of 'ligamentization'. During which chronological phase is the graft biomechanically at its weakest and most vulnerable to elongation or rupture?





Explanation

The graft undergoes four phases: initial necrosis, revascularization, cellular proliferation, and remodeling (ligamentization). The graft is biomechanically weakest during the early remodeling/revascularization phase (typically 4 to 12 weeks post-op). During this window, native cells undergo necrosis and the collagen matrix is reorganized, making the graft susceptible to stretch or failure before new collagen is adequately deposited and aligned.

Question 77

A 50-year-old female presents with acute medial knee pain after a deep squat. MRI reveals a complete radial tear of the posterior root of the medial meniscus. Biomechanically, this specific injury alters joint contact pressures in a manner equivalent to which of the following?





Explanation

A posterior root tear of the meniscus completely disrupts the circumferential hoop fibers of the meniscus. Biomechanical studies demonstrate that a complete root tear abolishes the meniscus's ability to resist hoop stresses and extrudes the meniscus, resulting in contact pressures and joint kinematics that are virtually equivalent to a total meniscectomy. Surgical repair is critical to restore hoop tension and prevent rapid osteoarthritis.

Question 78

According to the Musculoskeletal Infection Society (MSIS) / International Consensus Meeting (ICM) criteria, which of the following constitutes an absolute major criterion for the definitive diagnosis of a periprosthetic joint infection (PJI)?





Explanation

According to the MSIS/ICM criteria, the two major criteria (either of which definitively diagnoses a PJI on its own) are: 1) A sinus tract communicating directly with the prosthesis, and 2) Two positive periprosthetic cultures with phenotypically identical organisms. The other options are considered minor criteria, a combination of which is required to meet the definition of PJI if a major criterion is absent.

Question 79

A 38-year-old male presents with sudden onset, excruciating right shoulder pain that awakened him from sleep, lasting for 5 days before slowly resolving. Following pain resolution, he notices profound weakness in elevating and externally rotating his arm. MRI of the cervical spine and shoulder are normal. EMG demonstrates denervation isolated to the supraspinatus and infraspinatus. What is the most likely diagnosis?





Explanation

Parsonage-Turner syndrome (idiopathic brachial neuritis) classically presents with a viral prodrome followed by severe, acute shoulder/girdle pain lasting days to weeks. As the pain subsides, profound weakness and atrophy of the affected muscles (often innervated by the suprascapular, axillary, or long thoracic nerves) become apparent. The normal MRIs and classical biphasic clinical course distinguish it from structural tears or isolated compressive neuropathies.

Question 80

A 16-year-old boy presents with severe right shin pain that is significantly worse at night and dramatically improves with oral ibuprofen. Radiographs show a thickened cortical area in the tibial diaphysis surrounding a central 5mm radiolucent nidus. Which of the following best describes the expected histological appearance of the central nidus?





Explanation

The clinical and radiographic presentation is classic for an osteoid osteoma. Histologically, the central nidus of an osteoid osteoma is characterized by a sharply demarcated, highly vascularized area of interlacing networks of immature woven bone trabeculae rimmed by prominent, plump, but benign-appearing osteoblasts. Option 0 describes an osteochondroma; Option 1 describes a non-ossifying fibroma or GCT; Option 3 describes Ewing sarcoma.

Question 81

A 28-year-old male sustains a closed, comminuted midshaft femur fracture. He is hemodynamically stable. The surgeon considers using an unreamed intramedullary nail instead of a reamed intramedullary nail. Which of the following is the most significant clinical disadvantage of unreamed nailing compared to reamed nailing in this specific setting?





Explanation

Multiple randomized controlled trials and meta-analyses, including data from the SPRINT trial, have demonstrated that reamed intramedullary nailing of closed femoral shaft fractures yields significantly higher union rates and lowers the need for secondary bone grafting or dynamization compared to unreamed nailing. There is no significant difference in the incidence of pulmonary embolism, ARDS, or mortality between the two techniques, even in multiple trauma patients, provided they are adequately resuscitated.

Question 82

In the primary repair of a Zone II flexor digitorum profundus (FDP) tendon laceration, which of the following biomechanical variables contributes most significantly to the ultimate tensile strength of the repair?





Explanation

According to Strickland's principles of flexor tendon repair, the ultimate tensile strength of the repair is directly proportional to the number of core suture strands crossing the repair site. For example, a 4-strand repair is significantly stronger than a 2-strand repair. While locking knots, heavier suture caliber, and epitenon sutures (which add about 20% to the strength and smooth the repair) all contribute, the number of core strands is the single most critical factor for early active motion protocols.

Question 83

A 15-year-old boy presents with severe thigh pain. Radiographs reveal a destructive, permeative diaphyseal lesion of the femur with a prominent 'onion-skin' periosteal reaction. Histological evaluation confirms a small round blue cell tumor. Which of the following chromosomal translocations is most strongly associated with this patient's diagnosis?





Explanation

The clinical and radiographic presentation is classic for Ewing Sarcoma, a small round blue cell tumor. Ewing sarcoma is characterized by the t(11;22)(q24;q12) translocation in about 85-90% of cases, resulting in the EWS-FLI1 fusion protein. Synovial sarcoma is associated with t(X;18), myxoid liposarcoma with t(12;16), and alveolar rhabdomyosarcoma with t(2;13).

Question 84

A 6-year-old child sustains a completely displaced, extension-type supracondylar humerus fracture. Upon initial presentation in the emergency department, the child's hand is pink and warm, but the radial pulse is absent. The patient is taken to the operating room, where a successful closed reduction and percutaneous pinning are performed. Post-reduction, the hand remains pink with brisk capillary refill, but the radial pulse remains non-palpable. What is the most appropriate next step in management?





Explanation

The management of a 'pulseless, pink' hand following reduction of a supracondylar humerus fracture is observation. Because the hand is well-perfused via collateral circulation, immediate vascular exploration is not indicated. These patients should be admitted and undergo close serial neurovascular monitoring. Vascular exploration is indicated for a 'pulseless, pale' (ischemic) hand that does not improve after reduction.

Question 85

When evaluating a patient with recurrent anterior shoulder instability, the concept of the 'glenoid track' is utilized to determine the risk of a Hill-Sachs lesion engaging the anterior glenoid rim. Which of the following best describes an 'off-track' Hill-Sachs lesion?





Explanation

The glenoid track concept evaluates the interaction between bipolar bone loss (glenoid bone loss and Hill-Sachs lesion). The glenoid track represents the contact zone of the glenoid on the humeral head during abduction and external rotation. A Hill-Sachs lesion is 'off-track' (and thus will engage the anterior glenoid rim) if its medial margin extends further medial than the medial margin of the glenoid track.

Question 86

A 65-year-old woman presents with worsening right groin pain 4 years after a primary total hip arthroplasty. Her implant is a conventional metal-on-polyethylene bearing. Radiographs demonstrate a well-fixed stem and cup with no evidence of osteolysis. Serum inflammatory markers (ESR, CRP) are normal. Aspiration of the hip yields clear fluid with a low cell count. MRI with Metal Artifact Reduction Sequence (MARS) reveals a large, complex cystic pseudotumor adjacent to the femoral neck. Which of the following is the most likely etiology of her symptoms?





Explanation

The presence of an Adverse Local Tissue Reaction (ALTR) or pseudotumor in a metal-on-polyethylene total hip arthroplasty, combined with a normal infection workup and well-fixed components without massive osteolysis, points toward mechanically assisted crevice corrosion (MACC) at the modular head-neck junction (also known as trunnionosis). This corrosion releases metal ions that incite a lymphocytic inflammatory response.

Question 87

During the ilioinguinal approach for open reduction and internal fixation of an anterior column acetabular fracture, life-threatening hemorrhage occurs while dissecting along the posterior aspect of the superior pubic ramus. Which of the following vascular structures, which represents an anastomosis between the external iliac and obturator systems, is most likely injured?





Explanation

The 'corona mortis' (crown of death) is a highly variable vascular anastomosis between the external iliac (or inferior epigastric) vessels and the obturator vessels. It is classically located retropubically, approximately 5-7 cm from the pubic symphysis, crossing the superior pubic ramus. Injury to this structure during the ilioinguinal or Stoppa approach can lead to massive, difficult-to-control hemorrhage.

Question 88

A 24-year-old male sustains a purely ligamentous Lisfranc injury with lateral displacement of the second through fifth metatarsals. He undergoes operative management. Based on current orthopedic literature, what is the primary advantage of primary arthrodesis over open reduction and internal fixation (ORIF) for this specific injury pattern?





Explanation

Purely ligamentous Lisfranc injuries have poor healing potential compared to bony avulsion variants. Studies (such as those by Ly and Coetzee) have demonstrated that for purely ligamentous injuries, primary arthrodesis of the medial column (1st, 2nd, and 3rd TMT joints) provides superior or equivalent functional outcomes and significantly lower rates of reoperation (hardware removal and salvage fusion) compared to ORIF.

Question 89

According to Perren’s strain theory of bone healing, the type of tissue that forms in a fracture gap is determined by the local mechanical strain environment. Which of the following biological tissues can tolerate the highest degree of strain before mechanical failure?





Explanation

Perren's strain theory dictates that a tissue can only be formed in a fracture gap if the strain in that gap does not exceed the strain tolerance of the tissue. Granulation tissue can tolerate up to 100% strain without rupturing. As the fracture stabilizes and strain decreases, tissues with lower strain tolerance form: fibrocartilage tolerates 10-15% strain, woven bone tolerates about 5-10% strain, and lamellar bone tolerates only about 2% strain.

Question 90

A 30-year-old male undergoes a multi-ligament knee reconstruction following a traumatic knee dislocation. Six weeks postoperatively, he presents with a persistent, profound foot drop. Electromyography (EMG) reveals a severe, complete common peroneal nerve injury with no motor unit potentials and no signs of early reinnervation. The patient has zero active ankle dorsiflexion. If there is absolutely no clinical or electrodiagnostic recovery by 1 year post-injury, what is the most appropriate definitive surgical management to restore active ambulation without an orthosis?





Explanation

At 1 year post-injury with no clinical or EMG signs of recovery, a peroneal nerve injury is generally considered irreversible. Nerve repairs or grafts performed this late have dismal outcomes due to motor endplate atrophy. The gold standard definitive management for permanent common peroneal nerve palsy (foot drop) to restore active dorsiflexion is a tendon transfer, specifically the transfer of the functional tibialis posterior tendon to the dorsal midfoot (often through the interosseous membrane).

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