Orthopedic Surgery Board Review: 50 High-Yield MCQs

Question 1

In the structural organization of articular cartilage, which zone is characterized by the lowest concentration of water, the highest concentration of proteoglycans, and collagen fibers oriented perpendicular to the joint surface?

Explanation

The deep zone of articular cartilage contains the highest concentration of proteoglycans and the lowest water content. Its collagen fibers (primarily Type II) are arranged perpendicular to the articular surface to provide maximum resistance to compressive forces. The superficial zone has the highest water content and collagen aligned parallel to the surface to resist shear forces.

Question 2

A 28-year-old male sustains a Hawkins Type II talar neck fracture. At 8 weeks post-operation, an anteroposterior (AP) radiograph of the ankle reveals a distinct subchondral radiolucent band in the dome of the talus. What does this radiographic finding represent?

Explanation

This finding is known as the Hawkins sign. The subchondral radiolucent band represents subchondral osteopenia secondary to hyperemia and active bone resorption. It is a highly reliable indicator that the talar dome retains an intact vascular supply, essentially ruling out complete avascular necrosis.

Question 3

A 45-year-old manual laborer presents with chronic wrist pain and a history of an untreated scaphoid fracture years ago. Radiographs reveal a scaphoid nonunion with advanced radioscaphoid and capitolunate arthritis, but the radiolunate joint is well-preserved. Based on this specific pattern of arthritis (SNAC Stage III), which of the following is the most appropriate surgical treatment?

Explanation

The patient has Scaphoid Nonunion Advanced Collapse (SNAC) Stage III, which involves arthritis of the radioscaphoid and capitolunate joints with sparing of the radiolunate joint. Proximal row carpectomy (PRC) is contraindicated because it relies on a pristine articulation between the capitate head and the lunate fossa, and the capitate is already arthritic here. Scaphoid excision and four-corner fusion (capitate, hamate, lunate, triquetrum) removes the arthritic joints while preserving the intact radiolunate joint, maintaining some wrist motion.

Question 4

In a patient presenting with Stage II acquired adult flatfoot deformity (posterior tibial tendon dysfunction), physical examination and MRI often reveal attenuation of a key static stabilizing ligament that supports the talonavicular joint. Which of the following ligaments is most commonly affected in this scenario?

Explanation

The plantar calcaneonavicular ligament, commonly known as the spring ligament, is the primary static stabilizer of the longitudinal arch and the talonavicular joint. It is frequently attenuated or torn in conjunction with posterior tibial tendon dysfunction (PTTD), contributing to the characteristic talonavicular sag and abducted midfoot.

Question 5

The biomechanical properties of articular cartilage are dependent on its extracellular matrix. Which of the following components is primarily responsible for generating the tissue's compressive stiffness through osmotic swelling pressure?

Explanation

Aggrecan is the most abundant proteoglycan in articular cartilage. Its highly negatively charged glycosaminoglycan (GAG) side chains attract water, creating a strong osmotic swelling pressure. This swelling is resisted by the tensile strength of the Type II collagen network, providing articular cartilage with its characteristic compressive stiffness.

Question 6

A 45-year-old male feels a sudden 'pop' in his anterior elbow while lifting a heavy box. Clinical examination demonstrates a positive 'hook test.' If this patient opts for non-operative management of his distal biceps tendon rupture, which functional deficit will be most pronounced?

Explanation

A complete distal biceps tendon rupture leads to significant deficits in both forearm supination and elbow flexion. However, the loss of supination strength is much more pronounced (typically 40-50% loss) compared to the loss of elbow flexion strength (typically 30% loss) because the brachialis remains an intact and powerful elbow flexor.

Question 7

When initiating early functional rehabilitation for a patient undergoing non-operative management of an acute Achilles tendon rupture, what is the optimal initial ankle position in the functional brace to maximize tendon healing and prevent gapping?

Explanation

Non-operative management of Achilles tendon ruptures relies on early functional rehabilitation to promote organized collagen deposition. The initial immobilization must place the ankle in 20-30 degrees of plantar flexion to coapt the torn tendon ends and prevent gapping. The equinus angle is gradually reduced over several weeks.

Question 8

During an open in situ decompression of the ulnar nerve at the elbow, the surgeon must release a tough fascial band that bridges the two heads of the flexor carpi ulnaris (FCU) muscle to prevent entrapment. What is the name of this anatomic structure?

Explanation

Osborne's ligament (or Osborne's fascia) forms the roof of the cubital tunnel proper, spanning between the olecranon and the medial epicondyle (connecting the humeral and ulnar heads of the FCU). The Arcade of Struthers is a fascial band located ~8 cm proximal to the medial epicondyle. The Ligament of Struthers is an anomalous band compressing the median nerve. The Arcade of Frohse compresses the posterior interosseous nerve (PIN).

Question 9

A 22-year-old male athlete has a focal, symptomatic, full-thickness osteochondral defect of the medial femoral condyle measuring 2.5 cm^2. Which of the following factors makes him a better candidate for Osteochondral Autograft Transfer System (OATS) rather than microfracture?

Explanation

OATS involves the transplantation of cylindrical osteochondral plugs from non-weight-bearing areas to the defect. It is particularly advantageous over microfracture when there is underlying subchondral bone loss or a cyst, because the graft replaces both the deficient articular cartilage and the compromised subchondral bone. Microfracture relies on an intact subchondral bone plate to contain the marrow elements.

Question 10

The Lisfranc ligament is crucial for the stability of the midfoot and is frequently involved in high-energy foot trauma. Anatomically, this ligament originates from the medial cuneiform and inserts onto which structure?

Explanation

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

Question 11

A 35-year-old female presents after a fall onto an outstretched hand. She is diagnosed with a 'terrible triad' injury of the elbow (elbow dislocation, radial head fracture, and coronoid fracture). According to standard protocols, what is the recommended surgical sequence for repairing these injuries?

Explanation

The standard protocol for treating a terrible triad injury follows an 'inside-out' approach. The deep anterior structures are addressed first (coronoid fixation), followed by the lateral column (radial head fixation or replacement), and finally the lateral capsuloligamentous structures (LCL repair). The MCL is generally only repaired if the elbow remains grossly unstable after the lateral side is fixed.

Question 12

When a full-thickness articular cartilage defect extends through the tidemark into the subchondral bone, marrow-derived mesenchymal stem cells fill the defect. The resulting repair tissue is biomechanically inferior to native hyaline cartilage. Which type of collagen predominates in this repair tissue?

Explanation

Defects that penetrate the subchondral bone heal via the formation of fibrocartilage. Unlike native articular hyaline cartilage, which is predominantly composed of Type II collagen, fibrocartilage is primarily composed of Type I collagen. Type I collagen lacks the complex structural organization needed to resist the compressive and shear forces of the joint, leading to earlier degradation.

Question 13

A 21-year-old elite basketball player is diagnosed with a Jones fracture (fracture at the metaphyseal-diaphyseal junction of the 5th metatarsal). Surgical fixation with an intramedullary screw is planned. What anatomic feature is the primary reason for the notoriously high nonunion rate in this specific location?

Explanation

The high nonunion rate of a Jones fracture (Zone 2 of the 5th metatarsal) is primarily due to its location in a vascular watershed area. The blood supply to the base of the 5th metatarsal comes from metaphyseal vessels proximally and a nutrient artery distally, leaving the metaphyseal-diaphyseal junction relatively avascular.

Question 14

A 55-year-old diabetic woman presents with triggering and locking of her middle finger. Non-operative management has failed, and surgical release of the stenosing tenosynovitis is planned. Which annular pulley must be completely incised to reliably resolve this condition?

Explanation

Trigger finger (stenosing tenosynovitis) is caused by a size mismatch between the flexor tendon (often involving a nodule) and the A1 pulley, which lies over the metacarpophalangeal (MCP) joint. Complete surgical release of the A1 pulley resolves the triggering. The A2 and A4 pulleys must be preserved to prevent bowstringing of the flexor tendon.

Question 15

In the pathogenesis of osteoarthritis, matrix degradation outpaces synthesis. Which matrix metalloproteinase (MMP) is considered the primary and most potent enzyme responsible for the cleavage of Type II collagen in articular cartilage?

Explanation

MMP-13 (collagenase-3) is the primary enzyme responsible for the degradation of Type II collagen in articular cartilage during osteoarthritis. While MMP-1 also cleaves fibrillar collagen, MMP-13 is significantly more efficient at cleaving Type II collagen and is heavily upregulated in osteoarthritic chondrocytes.

Question 16

A surgeon utilizes the classic extensile lateral approach for the open reduction and internal fixation (ORIF) of a displaced intra-articular calcaneus fracture. During the elevation of the full-thickness subperiosteal flap, which nerve is at greatest risk of iatrogenic injury if the flap is not raised correctly?

Explanation

The sural nerve courses along the lateral aspect of the hindfoot and is at significant risk during the extensile lateral approach to the calcaneus. To protect it, a 'no-touch' technique is used where the nerve is elevated entirely within the full-thickness subperiosteal fasciocutaneous flap.

Question 17

The median nerve provides motor innervation to the majority of the thenar musculature via its recurrent motor branch. Which of the following intrinsic thumb muscles is typically innervated by the deep branch of the ulnar nerve?

Explanation

The thenar eminence consists of the abductor pollicis brevis (APB), opponens pollicis, and flexor pollicis brevis (FPB). The APB, opponens pollicis, and the superficial head of the FPB are innervated by the median nerve. The deep head of the FPB (along with the adductor pollicis) is innervated by the deep branch of the ulnar nerve.

Question 18

Articular cartilage is an avascular tissue, forcing chondrocytes to survive in a deeply hypoxic environment. Which primary transcription factor is upregulated in chondrocytes to mediate their survival, regulate energy metabolism, and maintain extracellular matrix synthesis under these low-oxygen conditions?

Explanation

Hypoxia-inducible factor 1-alpha (HIF-1 alpha) is the master transcriptional regulator of the cellular response to hypoxia. In the avascular articular cartilage, HIF-1 alpha is essential for chondrocyte survival, promoting glycolysis for ATP generation and supporting the synthesis of Sox9, Type II collagen, and aggrecan.

Question 19

A 50-year-old woman presents with severe, symptomatic hallux valgus. Weight-bearing radiographs reveal a Hallux Valgus Angle (HVA) of 45 degrees, an Intermetatarsal Angle (IMA) of 20 degrees, and clinical examination demonstrates gross hypermobility of the first tarsometatarsal (TMT) joint. Which surgical procedure is most indicated to correct the deformity and minimize the risk of recurrence?

Explanation

The patient has a severe bunion deformity (IMA > 15-20 degrees, HVA > 40 degrees) coupled with first ray hypermobility. The Lapidus procedure (arthrodesis of the first tarsometatarsal joint) is the treatment of choice in this scenario, as it powerfully corrects large IMA deformities and stabilizes the hypermobile medial column, significantly reducing the recurrence rate compared to distal osteotomies.

Question 20

In the context of flexor tendon injuries of the hand, which anatomical zone is historically termed 'No Man's Land' due to the high risk of post-operative adhesions and poor clinical outcomes?

Explanation

Zone II extends from the proximal edge of the A1 pulley to the insertion of the flexor digitorum superficialis (FDS) tendon. Bunnell coined the term 'No Man's Land' for this area because the flexor digitorum profundus (FDP) and FDS tendons run closely together within a tight fibro-osseous sheath, making surgical repair notoriously difficult and highly prone to debilitating scar adhesions.

Question 21

Which zone of articular cartilage has the highest concentration of water and the lowest concentration of proteoglycans, with collagen fibrils oriented parallel to the joint surface?

Explanation

The superficial (tangential) zone of articular cartilage contains the highest water content (up to 80%) and the lowest concentration of proteoglycans. The collagen fibrils (primarily Type II) are oriented parallel to the articular surface to resist shear forces and provide tensile strength.

Question 22

A 35-year-old manual laborer presents with chronic right wrist pain. Radiographs reveal advanced arthritis of the radioscaphoid and capitolunate joints, while the radiolunate joint is completely spared. Which of the following is the most appropriate motion-preserving surgical option?

Explanation

The patient has a Stage III Scapholunate Advanced Collapse (SLAC) wrist, characterized by arthritis of the radioscaphoid and capitolunate joints with a preserved radiolunate joint. Scaphoid excision and four-corner arthrodesis is the standard motion-preserving procedure. Proximal row carpectomy (PRC) is contraindicated because it relies on a healthy articulation between the lunate fossa of the radius and the head of the capitate; in Stage III SLAC, the capitate head is arthritic.

Question 23

A 45-year-old woman with Stage IIb adult-acquired flatfoot deformity is undergoing reconstruction. During the lateral column lengthening (Evans calcaneal osteotomy), which of the following structures is at greatest risk of iatrogenic injury if the saw blade exits too plantar and distal?

Explanation

During an Evans calcaneal osteotomy (which is performed approximately 1 to 1.5 cm proximal to the calcaneocuboid joint), the peroneus longus tendon is at greatest risk of injury. It courses obliquely along the plantar aspect of the cuboid groove, placing it in jeopardy if the osteotomy penetrates too deeply in the plantar-distal direction.

Question 24

A 28-year-old male sustains a 'terrible triad' injury of the elbow. Intraoperatively, after definitive internal fixation of the coronoid fracture and replacement of a highly comminuted radial head, the elbow exhibits persistent posterolateral rotatory instability. What is the most appropriate next step in management?

Explanation

The standard algorithm for treating a terrible triad injury (elbow dislocation, radial head fracture, coronoid fracture) involves restoring the anterior buttress (coronoid), restoring the lateral buttress (radial head repair or replacement), and then repairing the lateral ligamentous complex (specifically the LUCL) to the lateral epicondyle. If instability persists after LUCL repair, the MCL may be repaired or an external fixator applied.

Question 25

In the structural composition of native adult hyaline articular cartilage, which minor collagen primarily functions to cross-link fibrillar elements and regulate the diameter of the collagen fibrils?

Explanation

While Type II collagen constitutes 90-95% of the collagen in articular cartilage and provides the primary structural framework, Type IX (along with Type XI) is a minor collagens that plays a crucial role in covalently cross-linking the Type II fibrils, thereby regulating their diameter and stabilizing the matrix. Type X collagen is exclusively found in the calcified zone.

Question 26

A 14-year-old boy with Charcot-Marie-Tooth disease presents with a symptomatic, flexible cavovarus foot deformity. To correct the primary muscle imbalance and augment ankle dorsiflexion, which tendon transfer is most commonly performed?

Explanation

In Charcot-Marie-Tooth (CMT) disease, cavovarus deformity is driven by muscle imbalance: weak tibialis anterior and peroneus brevis against strong peroneus longus and tibialis posterior. Transferring the overactive tibialis posterior tendon through the interosseous membrane to the dorsum of the foot (often to the lateral cuneiform or cuboid) removes the deforming inversion force and provides active dorsiflexion, compensating for the weak anterior compartment.

Question 27

During a fasciectomy for severe Dupuytren's contracture involving the proximal interphalangeal (PIP) joint, the surgeon notes that the digital neurovascular bundle is displaced toward the midline and superficially. Which pathologic structure is primarily responsible for this displacement?

Explanation

The spiral cord in Dupuytren's disease is notorious for displacing the neurovascular bundle centrally, volarly (superficially), and proximally, placing it at high risk for transection during surgical release. The spiral cord is formed by the amalgamation of the pretendinous band, spiral band, lateral digital sheet, and Grayson's ligament.

Question 28

Six weeks after open reduction and internal fixation of a displaced talar neck fracture, an AP ankle radiograph reveals a subchondral radiolucent band in the dome of the talus (Hawkins sign). This radiographic finding indicates:

Explanation

The Hawkins sign is a subchondral radiolucent band seen in the talar dome on AP or mortise views at 6 to 8 weeks post-injury. It represents subchondral bone atrophy resulting from active hyperemia. This physiologic response requires an intact blood supply; therefore, the presence of a Hawkins sign is a highly reliable indicator that the talar body has preserved vascularity and that AVN is unlikely.

Question 29

Following a microfracture procedure for a symptomatic 1.5 cm^2 focal chondral defect on the medial femoral condyle, the resultant repair tissue is histologically evaluated. Compared to native articular cartilage, this repair tissue is predominantly characterized by an increased concentration of:

Explanation

Microfracture is a marrow-stimulating technique that allows pluripotent mesenchymal stem cells to enter the chondral defect, resulting in the formation of fibrocartilage rather than native hyaline cartilage. Fibrocartilage is primarily composed of Type I collagen, which has inferior biomechanical wear characteristics compared to the Type II collagen predominant in normal hyaline articular cartilage.

Question 30

A 24-year-old male is struck on the posterior distal humerus and presents with an inability to extend his thumb, MCP joints, or wrist. However, wrist extension is accompanied by radial deviation. There is no sensory deficit in the forearm or hand. The site of nerve entrapment or injury is most likely at the:

Explanation

The patient exhibits a posterior interosseous nerve (PIN) palsy. The preserved radial deviation during wrist extension occurs because the extensor carpi radialis longus (ECRL) and often ECRB are innervated by the radial nerve proximal to its bifurcation, while the extensor carpi ulnaris (ECU) is innervated by the PIN and is paralyzed. Lack of sensory deficit also points to PIN rather than the main radial nerve. The most common site of PIN compression/injury is the Arcade of Frohse (the proximal aponeurotic edge of the superficial head of the supinator).

Question 31

Which portion of the spring ligament complex (plantar calcaneonavicular ligament) is anatomically the strongest, attaches to the navicular tuberosity, and acts as the primary static restraint to plantar-medial subluxation of the talar head?

Explanation

The spring ligament is essential for supporting the medial longitudinal arch. The superomedial calcaneonavicular ligament is the broadest and strongest portion of this complex. It provides the primary hammock-like support beneath the talar head, preventing its plantar and medial subluxation in conditions like adult-acquired flatfoot deformity.

Question 32

Which large aggregating proteoglycan is the most abundant in articular cartilage, playing a pivotal role in retaining water within the extracellular matrix to resist compressive loads?

Explanation

Aggrecan is the predominant large proteoglycan in articular cartilage. It consists of a protein core with numerous glycosaminoglycan (GAG) side chains (chondroitin sulfate and keratan sulfate). These highly negatively charged GAGs attract sodium and water, creating the massive osmotic swelling pressure that imparts cartilage with its ability to withstand significant compressive loads.

Question 33

When performing the extended volar (Henry) approach to the distal radius and forearm, the surgeon exploits the internervous plane in the proximal forearm between the flexor carpi radialis (FCR) and the brachioradialis. This represents a safe interval between the territories of which two nerves?

Explanation

The volar Henry approach to the radius utilizes the internervous plane between the brachioradialis (innervated by the radial nerve) and the flexor carpi radialis (innervated by the median nerve). Retracting the brachioradialis laterally and the FCR medially provides access to the pronator teres and flexor pollicis longus, beneath which the radius lies.

Question 34

A 22-year-old collegiate football player suffers a high ankle sprain following an external rotation force to the dorsiflexed foot. In a purely ligamentous syndesmotic injury, biomechanical and clinical studies show which of the following ligaments is typically the first to rupture?

Explanation

In external rotation injuries of the ankle involving the syndesmosis, the sequential failure of ligaments typically begins anteriorly. The anterior inferior tibiofibular ligament (AITFL) is the first to tear, followed by the interosseous ligament, and lastly the posterior inferior tibiofibular ligament (PITFL) or a posterior malleolus avulsion.

Question 35

During open reduction and internal fixation of a highly comminuted, intra-articular distal radius fracture utilizing a volar locking plate, the surgeon identifies a 'die-punch' fragment comprising the volar margin of the lunate fossa. Failure to adequately capture and buttress this specific fragment is most likely to result in:

Explanation

The volar marginal fragment of the lunate fossa is a critical stabilizing structure of the radiocarpal joint because the short radiolunate ligament originates here. If this 'die-punch' fragment is not securely buttressed, the lunate (and subsequently the entire carpus) will follow the fragment, leading to a catastrophic volar subluxation or dislocation of the carpus.

Question 36

In the pathogenesis of osteoarthritis, which matrix metalloproteinase (MMP) is considered the most critical enzyme responsible for the direct cleavage and irreversible degradation of the Type II collagen fibrillar network?

Explanation

MMP-13 (collagenase-3) is heavily implicated in osteoarthritis. It is highly overexpressed in OA cartilage and has a strong preference for cleaving Type II collagen, leading to the irreversible breakdown of the primary structural framework of articular cartilage. MMP-3 (stromelysin-1) primarily degrades proteoglycans, while MMP-1 plays a lesser role in Type II collagen degradation.

Question 37

A 55-year-old active male undergoes surgical treatment for refractory insertional Achilles tendinopathy with a large calcaneal exostosis. During debridement, approximately 60% of the Achilles tendon insertion is detached to adequately resect the pathologic bone and degenerative tendon. What is the most appropriate intraoperative management?

Explanation

When more than 50% of the Achilles tendon insertion must be detached during debridement for insertional tendinopathy, primary repair alone is structurally insufficient and carries a high risk of rupture. The standard of care is to augment the repair with a local tendon transfer. The Flexor Hallucis Longus (FHL) is the preferred transfer due to its synergistic action (plantarflexion), strength, in-phase firing, and close anatomic proximity.

Question 38

A 60-year-old female presents with progressive dorsal foot pain and a rigid first metatarsophalangeal (MTP) joint. Radiographs show a loss of joint space, subchondral sclerosis, and a large dorsal osteophyte. The patient wishes to attempt conservative management. Which orthotic or shoe modification is most effective for managing this condition?

Explanation

The patient has advanced hallux rigidus. Pain is primarily elicited during dorsiflexion of the first MTP joint at terminal stance. A Morton's extension is a rigid material added to an orthotic under the first metatarsal and great toe to physically limit MTP joint dorsiflexion. Combined with a stiff-soled shoe or a rocker bottom, it effectively restricts painful joint excursion.

Question 39

In the microscopic anatomy of mature articular cartilage, the 'tidemark' serves as the histological boundary delineating which of the following structures?

Explanation

The tidemark is a metabolically active histological boundary that separates the deep (radial), uncalcified hyaline cartilage from the calcified cartilage zone. It is recognizable on H&E staining as a distinct basophilic line. The zone below the tidemark is tethered directly to the subchondral bone via the cement line.

Question 40

A 32-year-old man falls on an outstretched hand and presents with severe wrist pain. Radiographs demonstrate a perilunate dislocation. When assessing the injury on a PA radiograph, disruption of Gilula's lines is noted. The most commonly expected direction of dislocation for the distal carpal row relative to the lunate is:

Explanation

In a perilunate dislocation, the lunate typically remains in its normal position articulating with the radius, while the distal carpal row (capitate) and the rest of the carpus dislocate dorsally. This contrasts with a lunate dislocation, where the lunate is expelled volarly 'spilled teacup' while the capitate remains collinear with the radius. Perilunate dislocations account for the vast majority of these injuries and are typically dorsal.

Question 41

A 72-year-old female undergoes a reverse total shoulder arthroplasty for cuff tear arthropathy. How does this implant design alter the biomechanics of the glenohumeral joint compared to native anatomy?

Explanation

Reverse total shoulder arthroplasty (based on the Grammont design principles) medializes and inferiorly translates the center of rotation of the glenohumeral joint. This alteration significantly increases the lever arm of the deltoid muscle, allowing it to recruit more fibers for arm elevation in the absence of a functioning rotator cuff. It also decreases torque on the glenoid component.

Question 42

In normal articular cartilage, which zone is characterized by the highest concentration of proteoglycans, the lowest concentration of water, and collagen fibrils aligned perpendicular to the articular surface?

Explanation

The deep (radial) zone of articular cartilage contains the highest concentration of proteoglycans, the lowest water content, and the largest diameter collagen fibrils. These fibrils are oriented perpendicular to the joint surface to effectively resist and distribute compressive loads. In contrast, the superficial zone has the highest water content and lowest proteoglycan concentration.

Question 43

A 45-year-old runner presents with chronic posterior heel pain exacerbated by running uphill. MRI reveals insertional Achilles tendinopathy with calcification and greater than 50% tendon degeneration, alongside a prominent Haglund deformity. Nonoperative management has failed. Which surgical intervention is most appropriate?

Explanation

In patients with severe insertional Achilles tendinopathy where greater than 50% of the tendon is diseased and requires detachment/debridement, the repair should be augmented to prevent rupture and restore strength. An FHL transfer is the gold standard augmentation in this scenario, performed alongside calcaneal exostectomy (removal of the Haglund deformity) and diseased tendon debridement.

Question 44

A 40-year-old manual laborer presents with progressive wrist pain. Radiographs demonstrate a scaphoid nonunion with radioscaphoid arthritis and capitolunate arthritis, but the radiolunate joint is preserved. This corresponds to Scaphoid Nonunion Advanced Collapse (SNAC) Stage III. What is the most appropriate surgical treatment?

Explanation

SNAC Stage III involves arthritis of the radioscaphoid and capitolunate joints, while typically sparing the radiolunate joint. A four-corner arthrodesis (capitate, lunate, triquetrum, hamate) with scaphoid excision is the most appropriate treatment. Proximal row carpectomy (PRC) is contraindicated in the presence of capitolunate arthritis because the capitate will articulate directly with the lunate fossa, leading to rapid wear.

Question 45

A 28-year-old male sustains a Hawkins Type III talar neck fracture. Which of the following best describes the disruption of blood supply leading to the high risk of avascular necrosis (AVN) in this injury?

Explanation

A Hawkins Type III fracture is a talar neck fracture with dislocation of both the subtalar and tibiotalar joints. This displacement systematically disrupts all three major sources of blood supply to the talar body: the artery of the tarsal canal (from the posterior tibial artery), the artery of the sinus tarsi (from anterior tibial/peroneal branches), and the deltoid branches (from the posterior tibial artery), resulting in a very high risk of AVN.

Question 46

In the pathogenesis of osteoarthritis, which matrix metalloproteinase (MMP) is recognized as the primary enzyme responsible for the cleavage and degradation of Type II collagen in articular cartilage?

Explanation

MMP-13 (collagenase-3) is heavily upregulated in osteoarthritic cartilage and is the principal enzyme responsible for the irreversible degradation of Type II collagen. MMP-3 (stromelysin) primarily degrades proteoglycans (aggrecan), while MMP-1 is more active against Type I and III collagens.

Question 47

A 50-year-old male undergoes in situ ulnar nerve decompression for cubital tunnel syndrome. To ensure complete decompression, the surgeon must check for several potential sites of entrapment. Which of the following is the most distal structure that commonly compresses the ulnar nerve in this region?

Explanation

The potential sites of ulnar nerve compression around the elbow, from proximal to distal, are: the Arcade of Struthers, the medial intermuscular septum, the medial epicondyle, Osborne's ligament (cubital tunnel retinaculum), and the aponeurosis of the two heads of the flexor carpi ulnaris (FCU). The ligament of Struthers is associated with median nerve compression in the distal humerus.

Question 48

Based on recent randomized controlled trials, primary arthrodesis is most strongly recommended over open reduction internal fixation (ORIF) for which type of acute Lisfranc injury?

Explanation

Multiple studies, including landmark papers by Coetzee and Lykomitros, have demonstrated that purely ligamentous Lisfranc injuries treated with primary arthrodesis (of the 1st, 2nd, and 3rd TMT joints) yield superior functional outcomes and lower reoperation rates compared to ORIF. ORIF of ligamentous injuries has a high rate of hardware failure and late post-traumatic arthritis.

Question 49

Lubricin (PRG4) is a critical glycoprotein for boundary lubrication in synovial joints. Which cells are primarily responsible for synthesizing and secreting lubricin in healthy articular cartilage?

Explanation

Lubricin (proteoglycan 4 or PRG4) is synthesized primarily by superficial zone chondrocytes and synoviocytes. It localizes to the articular surface where it provides crucial boundary lubrication, significantly reducing friction and wear during joint movement.

Question 50

A 60-year-old male presents with pseudoparalysis and intractable shoulder pain. MRI shows a massive, retracted, and irreparable tear of the supraspinatus and infraspinatus tendons. The subscapularis, teres minor, and articular cartilage are intact. Which procedure is most appropriate?

Explanation

Superior Capsular Reconstruction (SCR) is indicated for massive, irreparable posterosuperior rotator cuff tears in active patients with intact articular cartilage (no glenohumeral arthritis), a functioning deltoid, and an intact or repairable subscapularis. It helps restore the superior restraint to humeral head translation. Latissimus dorsi transfer requires an intact subscapularis but SCR more effectively prevents superior escape when the superior capsule is deficient.

Question 51

A 55-year-old female presents with stage IIb posterior tibial tendon dysfunction. She has a flexible flatfoot deformity but experiences significant lateral foot pain during stance phase due to subfibular impingement. There is more than 40% uncoverage of the talar head. Which of the following surgical strategies is most appropriate?

Explanation

Stage IIb adult acquired flatfoot deformity is characterized by a flexible deformity with significant forefoot abduction (typically >40% talonavicular uncoverage). This degree of abduction requires a lateral column lengthening (e.g., Evans osteotomy) to correct, in addition to an FDL transfer and often a medial displacement calcaneal osteotomy (MDCO) for valgus correction. Triple arthrodesis is reserved for rigid deformities (Stage III).

Question 52

A 14-year-old male baseball pitcher complains of lateral elbow pain and catching. Radiographs show a radiolucent lesion of the capitellum. MRI demonstrates an osteochondral lesion with fluid tracking behind the fragment. What is the most appropriate management?

Explanation

Fluid tracking behind an osteochondral fragment on MRI signifies an unstable osteochondritis dissecans (OCD) lesion. In an adolescent with an unstable lesion, operative management is indicated. Depending on fragment viability, fixation of the fragment or an osteochondral autograft transfer (OATS) provides the best chance to restore the articular surface. Microfracture alone for a large capitellar lesion in a high-demand thrower is often structurally insufficient.

Question 53

A 32-year-old carpenter presents with dorsal wrist pain. X-rays show sclerosis of the lunate with mild collapse, but the carpal height is maintained, and there is no fixed scaphoid rotation or osteoarthritis. He has ulnar minus variance. Which surgical option is most appropriate?

Explanation

The patient has Lichtman Stage II or early Stage IIIA Kienböck's disease (lunate sclerosis and mild collapse without carpal collapse or fixed scaphoid rotation) associated with ulnar minus variance. A joint-leveling procedure, such as a radial shortening osteotomy, unloads the lunate, limits further collapse, and can promote revascularization. Salvage procedures like PRC are reserved for advanced stages (IIIB or IV).

Question 54

A 21-year-old collegiate basketball player sustains a zone 2 fracture (Jones fracture) of the proximal fifth metatarsal. Intramedullary screw fixation is planned. To optimize biomechanical stability and reduce the risk of nonunion or refracture, what are the ideal characteristics of the implant?

Explanation

In elite athletes, intramedullary screw fixation for Jones fractures is preferred to optimize early return to play. The biomechanically superior construct uses the largest diameter screw that comfortably fits the canal (usually 4.5 mm to 5.5 mm) to maximize bending stiffness. Solid screws are stronger than cannulated screws. The screw should ideally be long enough that all threads bypass the fracture site, gaining purchase in the diaphyseal isthmus.

Question 55

Following arthroscopic microfracture for a 1.5 cm^2 symptomatic focal chondral defect on the medial femoral condyle, what is the predominant collagen type found in the reparative tissue at 1 year postoperatively?

Explanation

Microfracture is a marrow-stimulating technique that leads to the formation of fibrocartilage rather than normal hyaline cartilage. Fibrocartilage is predominantly composed of Type I collagen, whereas normal hyaline articular cartilage is predominantly composed of Type II collagen. This histologic difference accounts for the poorer long-term biomechanical durability of microfracture repairs.

Question 56

During the volar approach (modified Henry) for plating a distal radius fracture, the surgeon must avoid placing the plate distal to the 'watershed line' to prevent which of the following complications?

Explanation

The 'watershed line' is a bony ridge on the volar margin of the distal radius. If a volar plate is placed distal to this line, it acts as a prominent friction point against the overlying flexor tendons. The Flexor Pollicis Longus (FPL) is most intimately related to this area and is at the highest risk for attritional rupture due to hardware impingement.

Question 57

A 62-year-old male presents with big toe pain. Examination reveals less than 10 degrees of dorsiflexion at the first MTP joint with pain at the mid-range of motion. Radiographs show significant joint space narrowing, dorsal osteophytes, and a flattened metatarsal head. Which treatment is considered the gold standard for this advanced (Grade 3/4) hallux rigidus?

Explanation

Advanced hallux rigidus (Coughlin and Shurnas Grade 3 or 4) presents with severe motion restriction, significant joint space loss, and pain even in the mid-range of motion. The gold standard surgical treatment is a first MTP joint arthrodesis, which provides predictable and long-lasting pain relief. Cheilectomy is indicated for Grade 1 and 2 where mid-arc motion is painless.

Question 58

Matrix-induced Autologous Chondrocyte Implantation (MACI) was developed to overcome some limitations of first-generation ACI. Which of the following best describes the primary modification introduced in MACI?

Explanation

First-generation ACI utilized cultured chondrocytes injected under a periosteal patch, which was associated with high rates of patch hypertrophy. MACI (Matrix-induced ACI) involves culturing the autologous chondrocytes and seeding them onto a bioabsorbable porcine-derived Type I/III collagen membrane. This membrane is then cut to size and glued or sutured into the defect, bypassing the need for a periosteal harvest.

Question 59

In zone II flexor tendon injuries, preserving or reconstructing the annular pulley system is crucial to prevent bowstringing and maintain digital flexion efficiency. Biomechanically, which two pulleys are the most critical to preserve?

Explanation

The A2 pulley (located over the proximal aspect of the proximal phalanx) and the A4 pulley (located over the middle of the middle phalanx) are the most biomechanically critical components of the flexor tendon sheath. Loss of these specific pulleys leads to profound bowstringing, diminished active range of motion, and loss of mechanical advantage during finger flexion.

Question 60

A 55-year-old diabetic patient presents with an acute, warm, swollen, and erythematous midfoot. Radiographs show fragmentation and early collapse of the midfoot with no open ulcers. Infection is ruled out. According to the Eichenholtz classification, what is the most appropriate initial management for this Stage I Charcot arthropathy?

Explanation

Acute (Eichenholtz Stage I - developmental/fragmentation) Charcot neuroarthropathy is characterized by profound active inflammation, bone fragmentation, and joint subluxation. The gold standard initial management is strict immobilization using a total contact cast and non-weight bearing to arrest the inflammatory process and prevent further collapse. Surgical reconstruction during this acute phase has an unacceptably high rate of failure and hardware pullout.

Question 61

Which of the following zones of normal articular cartilage contains the lowest concentration of water, the highest concentration of proteoglycans, and collagen fibers oriented strictly perpendicular to the articular surface?

Explanation

The deep (basal) zone of articular cartilage is characterized by the lowest water content, the highest proteoglycan content, and large-diameter Type II collagen fibers oriented perpendicular to the articular surface. This architecture provides maximum resistance to compressive forces. The superficial zone has the highest water content and collagen fibers parallel to the joint surface to resist shear forces.

Question 62

A 58-year-old male presents with severe, end-stage post-traumatic ankle osteoarthritis and is being evaluated for a Total Ankle Arthroplasty (TAA). Which of the following represents an absolute contraindication to proceeding with TAA?

Explanation

Avascular necrosis (AVN) of greater than 50% of the talar body is an absolute contraindication to Total Ankle Arthroplasty (TAA) due to inadequate viable bone stock for implant fixation and a high risk of subsequent component subsidence and failure. Concomitant subtalar arthritis is actually a relative indication for TAA over arthrodesis to preserve remaining hindfoot motion, or it can be addressed simultaneously.

Question 63

During surgical approach and debridement for refractory lateral epicondylitis, care must be taken to avoid iatrogenic injury to the lateral ulnar collateral ligament (LUCL). What is the anatomic location of the LUCL origin relative to the extensor carpi radialis brevis (ECRB) origin?

Explanation

The lateral ulnar collateral ligament (LUCL) originates on the lateral epicondyle posterior and deep to the origin of the extensor carpi radialis brevis (ECRB) and the common extensor tendon. It then traverses distally to insert on the supinator crest of the ulna. Overzealous deep and posterior surgical release of the ECRB can result in iatrogenic posterolateral rotatory instability (PLRI) of the elbow.

Question 64

Based on the Grammont principles of Reverse Total Shoulder Arthroplasty (rTSA), how does the implant biomechanically alter the glenohumeral joint's center of rotation compared to the native anatomy?

Explanation

The classical Grammont design for Reverse Total Shoulder Arthroplasty (rTSA) medializes and inferiorizes the center of rotation. Medialization increases the deltoid moment arm and recruits more anterior and posterior deltoid fibers for elevation. Inferiorization tensions the deltoid, compensating for an absent or non-functional rotator cuff.

Question 65

A 22-year-old male with Charcot-Marie-Tooth disease presents with a symptomatic cavovarus foot. On examination, a Coleman block test is performed by placing a 1-inch block under the lateral border of the foot, allowing the first ray to drop off. This maneuver results in complete correction of the hindfoot varus to neutral. Based on this finding, which of the following is the most appropriate foundational surgical step?

Explanation

The Coleman block test evaluates hindfoot flexibility in a cavovarus foot. If dropping the first ray off the block corrects the hindfoot varus to neutral, it indicates that the hindfoot varus is a flexible, compensatory deformity driven by a rigid, plantarflexed first ray. The primary bony procedure required in this flexible hindfoot scenario is a dorsiflexion osteotomy of the 1st metatarsal, usually accompanied by soft tissue releases (e.g., plantar fascia release).

Question 66

Boundary lubrication of normal articular cartilage is essential for minimizing friction during low-speed, high-load conditions. Which specific molecule is primarily responsible for boundary lubrication at the cartilage surface?

Explanation

Lubricin, also known as proteoglycan 4 (PRG4), is a glycoprotein secreted by superficial zone chondrocytes and synovial fibroblasts. It is the primary molecule responsible for boundary lubrication of articular cartilage, physically binding to the articular surface to reduce friction and prevent wear during low-speed, high-load interactions. Hyaluronic acid contributes to fluid-film lubrication but is not the primary boundary lubricant.

Question 67

A purely ligamentous Lisfranc injury is highly unstable due to the inherent bony anatomy of the midfoot. The absence of which of the following normal anatomic structures primarily predisposes the foot to this specific diastasis?

Explanation

The Lisfranc joint's stability is compromised by the natural absence of a transverse intermetatarsal ligament between the 1st and 2nd metatarsal bases. The 2nd through 5th metatarsals are connected by intermetatarsal ligaments, but the 1st and 2nd rely entirely on the Lisfranc ligament (which connects the medial cuneiform to the base of the 2nd metatarsal) for stability, making it a critical structure and a point of vulnerability.

Question 68

A 45-year-old male presents with isolated weakness when attempting to pinch his thumb and index finger together, specifically unable to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger (positive "OK" sign). He has normal sensation. Compression of the involved nerve is most likely caused by which anomalous structure?

Explanation

The patient has Anterior Interosseous Nerve (AIN) syndrome, indicated by weakness of the flexor pollicis longus (FPL), flexor digitorum profundus (FDP) to the index/middle fingers, and pronator quadratus, without sensory deficits. Gantzer's muscle, which is an accessory head of the FPL, is a well-known anatomical anomaly that can compress the AIN. The Arcade of Frohse compresses the PIN.

Question 69

Autologous Chondrocyte Implantation (ACI / MACI) is an established cell-based treatment for full-thickness articular cartilage defects. Which of the following scenarios represents the most ideal indication for this procedure?

Explanation

Autologous Chondrocyte Implantation (ACI/MACI) is indicated for symptomatic, large (>2.0 to 3.0 cm^2), full-thickness, unipolar articular cartilage defects in young, active patients (typically < 50 years old) without advanced osteoarthritis. Defects smaller than 2.0 cm^2 are better treated with microfracture or OATS. Bipolar kissing lesions and moderate-to-severe OA are contraindications.

Question 70

In Scapholunate Advanced Collapse (SLAC) of the wrist, progressive osteoarthritis occurs in a predictable pattern, typically advancing from the radioscaphoid joint to the capitolunate joint. Which biomechanical factor best explains why the radiolunate joint is consistently spared?

Explanation

In the SLAC wrist, the radioscaphoid joint degenerates first because the distal pole of the scaphoid rotates into flexion, creating incongruence and pathological shear stresses against the elliptical scaphoid fossa. In contrast, the lunate fossa of the distal radius and the proximal lunate are spherically congruent. Even when the lunate rotates into extension (DISI deformity), it remains concentrically loaded without abnormal shear forces, thereby preserving the radiolunate articular cartilage.

Question 71

A 55-year-old patient undergoes surgical debridement for chronic insertional Achilles tendinopathy. During the procedure, the surgeon excises the retrocalcaneal exostosis (Haglund's deformity) and debrides severely degenerated tendon tissue. At the conclusion of the debridement, it is noted that 65% of the Achilles tendon insertion has been removed. What is the most appropriate next step in management?

Explanation

In the surgical treatment of insertional Achilles tendinopathy, if more than 50% of the tendon insertion is debrided due to extensive tendinosis, standard primary repair with suture anchors is insufficient. Augmentation with a Flexor Hallucis Longus (FHL) tendon transfer is the gold standard step to restore strength, provide robust vascularized tissue, and bridge the defect.

Question 72

Which of the following best describes the predominant collagen type found in normal articular cartilage and its primary biomechanical function?

Explanation

Type II collagen comprises 90-95% of the collagen in normal articular cartilage. The highly cross-linked Type II collagen fibril network functions primarily to resist tensile forces and constrain the swelling pressure generated by proteoglycans (aggrecan). Proteoglycans and water are responsible for providing compressive stiffness, not the collagen itself.

Question 73

A 24-year-old athlete undergoes an MRI of the ankle for chronic pain, revealing a deep, cup-shaped osteochondral lesion of the talus. Based on the standard mnemonic "DIAL a PIMP", what is the most likely location and corresponding mechanism of injury for this specific morphology of lesion?

Explanation

The mnemonic "DIAL a PIMP" helps recall the location and mechanism of talar osteochondral lesions: DIAL (Dorsiflexion-Inversion -> AnteroLateral) and PIMP (Plantarflexion-Inversion -> PosteroMedial). Anterolateral lesions are typically shallow, wafer-shaped, and usually traumatic. Posteromedial lesions are typically deep, cup-shaped, and more often insidious or less directly tied to a single acute trauma, though they are biomechanically related to plantarflexion-inversion.

Question 74

Proximal pole fractures of the scaphoid are notorious for a high rate of avascular necrosis and nonunion. This complication is driven by the retrograde blood supply of the scaphoid. The primary intraosseous vascular supply enters the scaphoid at which of the following anatomic locations?

Explanation

The primary blood supply to the scaphoid is derived from the dorsal carpal branch of the radial artery, which enters the bone via the dorsal ridge located on the distal half (roughly 70-80% of the blood supply). Because blood flows retrograde from distal to proximal, fractures at the waist or proximal pole disrupt perfusion to the proximal segment, making it highly susceptible to avascular necrosis (AVN).

Question 75

During an Osteochondral Autograft Transfer System (OATS) procedure for a focal medial femoral condyle defect, cartilage plugs are harvested from a non-weight-bearing area, such as the peripheral trochlea. What is a recognized biomechanical disadvantage of these harvested donor osteochondral plugs compared to the native weight-bearing cartilage they are replacing?

Explanation

Cartilage thickness and biomechanical properties vary topographically within the knee based on loading. Cartilage harvested from non-weight-bearing regions (like the superolateral trochlea or intercondylar notch) is biomechanically inferior to weight-bearing cartilage. Specifically, it has lower compressive stiffness, a lower proteoglycan content, and may be of a mismatched thickness, which can affect long-term durability when transferred to a high-load zone.

Question 76

A 40-year-old female is evaluated for surgical management of a moderate hallux valgus deformity. Preoperative weight-bearing radiographs demonstrate a congruous first metatarsophalangeal (MTP) joint, but the Distal Metatarsal Articular Angle (DMAA) is abnormally elevated at 25 degrees. If the surgeon performs a simple medial eminence excision and a standard proximal chevron osteotomy without modifying the DMAA, what is the most likely complication?

Explanation

The Distal Metatarsal Articular Angle (DMAA) describes the orientation of the metatarsal head articular surface relative to its shaft. If the joint is congruous but the DMAA is elevated, the articular surface is naturally deviated laterally. If a standard translating osteotomy (like a standard chevron) is used to straighten the toe without correcting the articular orientation (e.g., via a biplanar chevron or Reverdin osteotomy), the surgeon will create an iatrogenic incongruous joint, leading to subluxation, stiffness, and early degenerative changes.

Question 77

In a volar Barton's fracture, the carpus typically subluxates volarly in conjunction with the volar marginal fracture fragment of the distal radius. Which of the following ligaments remains firmly attached to the lunate facet fragment, pulling the carpus volarly?

Explanation

A volar Barton's fracture involves the volar lip of the distal radius lunate fossa. The short radiolunate ligament attaches firmly to this specific volar marginal fragment. When the fragment fractures and displaces volarly, the short radiolunate ligament pulls the lunate (and thus the rest of the carpus) along with it, causing the characteristic volar radiocarpal subluxation.

Question 78

The distal tibiofibular syndesmosis is stabilized by several key ligamentous structures. During biomechanical testing, which specific ligament provides the greatest proportion of resistance (approximately 42%) against lateral displacement of the fibula (diastasis)?

Explanation

While the Anterior Inferior Tibiofibular Ligament (AITFL) is the most commonly injured ligament in syndesmotic sprains, biomechanical studies demonstrate that the Posterior Inferior Tibiofibular Ligament (PITFL) provides the greatest structural resistance to diastasis (lateral displacement), contributing approximately 42% of the overall syndesmotic strength. The AITFL contributes roughly 35%, and the interosseous ligament contributes about 22%.

Question 79

Biochemical changes in articular cartilage differ significantly between normal physiologic aging and the onset of early osteoarthritis (OA). Which of the following biochemical alterations is characteristic of EARLY osteoarthritis, distinguishing it from normal aging cartilage?

Explanation

In early osteoarthritis, there is a disruption of the Type II collagen fibril network. This breakdown reduces the constraint on the hydrophilic proteoglycan aggregates, allowing them to swell, resulting in an INCREASED total water content. In contrast, normal aging cartilage is characterized by a DECREASED total water content, smaller proteoglycan size, and an increased ratio of keratin sulfate to chondroitin sulfate.

Question 80

To prevent significant biomechanical bowstringing of the flexor pollicis longus (FPL) tendon and loss of thumb interphalangeal flexion strength, which pulley within the thumb flexor pulley system is considered the most critical to preserve during surgery?

Explanation

The thumb flexor pulley system consists of the A1, oblique, and A2 pulleys. The oblique pulley is classically considered the most biomechanically critical pulley in the thumb to prevent bowstringing of the FPL tendon and maintain effective excursion and flexion of the IP joint. Loss of the oblique pulley, especially in combination with the A1 pulley, leads to significant bowstringing.

Question 81

During the surgical repair of a Zone II flexor tendon laceration, the surgeon must carefully preserve the intrinsic vascular supply to the tendon. Which of the following structures provides the primary intrinsic blood supply to the flexor tendons within the digital fibro-osseous sheath?

Explanation

Within the digital sheath, flexor tendons receive their intrinsic blood supply through the vincula (brevia and longa), which carry vessels from the digital arteries to the dorsal aspect of the tendons. Synovial diffusion provides nutrition but is not the structural vascular supply.

Question 82

A 35-year-old athlete undergoes an arthroscopic evaluation of the knee. The health of the articular cartilage surface relies heavily on boundary lubrication to minimize friction. Which of the following glycoproteins is primarily responsible for boundary lubrication of articular cartilage?

Explanation

Lubricin (Proteoglycan 4 or PRG4) is synthesized by superficial zone chondrocytes and synoviocytes, playing the critical role in boundary lubrication of the articular surface. Hyaluronic acid primarily contributes to fluid-film lubrication.

Question 83

A 22-year-old football player presents with severe midfoot pain after his foot was axially loaded in plantarflexion. A weight-bearing AP radiograph reveals widening between the first and second metatarsal bases with a distinct "fleck sign". This pathognomonic radiographic sign represents an avulsion fracture at which of the following anatomical attachments?

Explanation

The "fleck sign" in a Lisfranc injury represents a bony avulsion of the Lisfranc ligament from the base of the second metatarsal. The ligament travels from the medial cuneiform to the base of the second metatarsal and typically avulses from the metatarsal side.

Question 84

A 40-year-old mechanic sustains a fall onto an outstretched hand, resulting in a complex carpal injury. Subsequent radiographs demonstrate a volar intercalated segment instability (VISI) deformity. This specific carpal alignment pattern is most strongly associated with a complete tear of which of the following ligaments?

Explanation

A VISI deformity occurs when the lunate flexes volarly, typically due to the loss of the extending force from the triquetrum following a lunotriquetral interosseous ligament tear. In contrast, scapholunate tears lead to a dorsal intercalated segment instability (DISI) pattern.

Question 85

A 30-year-old male sustains a severely comminuted, displaced intra-articular calcaneus fracture. The surgeon elects to proceed with open reduction and internal fixation via an extensile lateral approach. Which nerve is at greatest risk of iatrogenic injury during the dissection of the inferior horizontal limb of this surgical approach?

Explanation

The sural nerve crosses the lateral border of the foot and is at significant risk during the inferior incision of the extensile lateral approach to the calcaneus. Meticulous creation of a full-thickness subperiosteal flap is critical to protect it.

Question 86

In the pathogenesis of osteoarthritis, the articular cartilage undergoes progressive biochemical and structural degradation. Which of the following represents the earliest detectable biochemical alteration in osteoarthritic articular cartilage?

Explanation

The earliest biochemical change in osteoarthritis is an increase in water content due to the disruption of the collagen network. This leads to swelling of the cartilage matrix and a subsequent decrease in proteoglycan concentration.

Question 87

A 28-year-old gymnast falls onto her outstretched arm and presents with severe elbow instability. She is diagnosed with a "terrible triad" injury of the elbow. Which of the following accurately describes the three distinct components of this injury pattern?

Explanation

The terrible triad of the elbow classically consists of a posterior elbow dislocation, a radial head fracture, and a coronoid fracture. It is notorious for severe instability and often requires surgical fixation of the coronoid and radial head, along with LCL repair.

Question 88

A 55-year-old poorly controlled diabetic patient presents with a painless, swollen, erythematous right foot. Radiographs reveal extensive subchondral fragmentation, subluxation of the midfoot joints, and intra-articular debris without evidence of bony consolidation. According to the Eichenholtz classification, what stage of Charcot arthropathy does this represent?

Explanation

Eichenholtz Stage 1 (Development/Fragmentation) is characterized by joint edema, erythema, bony fragmentation, subluxation, and intra-articular debris. Stage 2 is coalescence (absorption of debris), and Stage 3 is reconstruction (remodeling and consolidation).

Question 89

A 68-year-old male presents with chronic shoulder pain and inability to actively elevate his arm above 40 degrees (pseudoparalysis). MRI shows a massive, retracted, fatty-infiltrated rotator cuff tear involving the supraspinatus and infraspinatus. Radiographs display severe superior migration of the humeral head with acetabularization of the acromion (Hamada Stage 4). What is the most appropriate surgical intervention?

Explanation

Reverse total shoulder arthroplasty is the treatment of choice for an elderly patient with rotator cuff tear arthropathy (Hamada Stage 4) and pseudoparalysis. It relies on the deltoid to restore elevation while addressing glenohumeral arthritis.

Question 90

A 24-year-old soccer player undergoes a knee arthroscopy for a 1.5 cm symptomatic focal chondral defect on the medial femoral condyle. The surgeon performs a marrow stimulation technique (microfracture). The primary reparative tissue that will fill this defect is predominantly composed of which of the following?

Explanation

Microfracture stimulates bleeding from the subchondral bone, leading to the formation of a fibrocartilage clot. Fibrocartilage is primarily composed of Type I collagen, which is biomechanically inferior to native hyaline cartilage (Type II collagen).

Question 91

According to the Lauge-Hansen classification for ankle fractures, a Supination-External Rotation (SER) injury follows a predictable sequence of structural failure. What is the first structure to fail in this specific mechanism?

Explanation

In the Lauge-Hansen SER mechanism, the sequence of injury is: 1) AITFL tear, 2) short oblique fibular fracture (typically posteroinferior to anterosuperior), 3) PITFL tear or posterior malleolus fracture, and 4) medial malleolus fracture or deltoid ligament tear.

Question 92

A 21-year-old rugby player presents with an inability to actively flex the distal interphalangeal (DIP) joint of his ring finger after grabbing an opponent's jersey. Examination shows tenderness in the palm. Imaging confirms a Type 1 flexor digitorum profundus (FDP) avulsion (Jersey finger) retracted into the palm. What is the most critical timing consideration for surgical repair of this specific injury type?

Explanation

A Type 1 Jersey finger involves retraction of the FDP tendon into the palm, disrupting both vincula and depriving the tendon of its blood supply. Surgical repair must be performed within 7 to 10 days to prevent permanent tendon necrosis and contracture.

Question 93

A partial-thickness articular cartilage laceration that does not penetrate the tidemark into the subchondral bone is observed incidentally during arthroscopy. Which of the following best describes the expected physiological healing response of this specific lesion?

Explanation

Partial-thickness cartilage injuries do not violate the subchondral bone and therefore do not access the marrow elements necessary for a hematoma or stem cell response. Consequently, they elicit little to no healing response due to the avascular nature of articular cartilage.

Question 94

A 45-year-old recreational basketball player feels a "pop" in his posterior ankle followed by weakness in plantarflexion. He is diagnosed with an acute Achilles tendon rupture. The tear occurs in the "watershed" zone, an area of relative hypovascularity. Where is this zone anatomically located relative to the calcaneal insertion?

Explanation

The "watershed" zone of the Achilles tendon is an area of diminished blood supply located approximately 2 to 6 cm proximal to its insertion on the calcaneus. This hypovascularity predisposes this specific region to degenerative changes and subsequent acute rupture.

Question 95

A patient with severe chronic cubital tunnel syndrome is asked to pinch a piece of paper between their thumb and index finger. The examiner notes compensatory hyperflexion of the thumb interphalangeal (IP) joint (a positive Froment's sign). This clinical finding is driven by the weakness of which of the following specific muscles?

Explanation

Froment's sign occurs due to weakness of the ulnar-innervated adductor pollicis muscle. To compensate for the inability to strongly adduct the thumb during pinch, the patient recruits the median-innervated flexor pollicis longus, leading to thumb IP hyperflexion.

Question 96

A 52-year-old obese female presents with a progressive, painful flatfoot deformity. Examination reveals she is unable to perform a single-leg heel rise. Weight-bearing radiographs show a flexible deformity with greater than 40% talonavicular uncoverage but no significant degenerative joint changes. This is consistent with Stage IIb adult acquired flatfoot deformity. Which of the following is the most appropriate reconstructive surgical plan?

Explanation

Stage IIb posterior tibial tendon dysfunction indicates a flexible flatfoot with significant forefoot abduction (>40% TN uncoverage). Appropriate treatment includes FDL transfer to the navicular, a medializing calcaneal osteotomy, and a lateral column lengthening (e.g., Evans osteotomy) to correct the severe abduction.

Question 97

A 32-year-old male sustains a distal radius fracture combined with a distal radioulnar joint (DRUJ) dislocation. Following anatomic reduction and fixation of the radius, the DRUJ remains grossly unstable in supination. The primary anatomical stabilizer of the DRUJ that is likely disrupted in this injury is the:

Explanation

The Triangular Fibrocartilage Complex (TFCC), specifically its deep dorsal and volar radioulnar ligaments (ligamentum subcruentum), is the primary stabilizer of the distal radioulnar joint (DRUJ). Disruption leads to gross DRUJ instability despite anatomic radius fixation.

Question 98

In the ultrastructural organization of articular hyaline cartilage, specific zones exhibit distinct cellular and matrix architectures. Which zone is characterized by the largest diameter collagen fibers oriented perpendicular to the joint surface and chondrocytes arranged in vertical columns?

Explanation

The deep (radial) zone of articular cartilage contains chondrocytes arranged in vertical columns parallel to the collagen fibers, which are oriented perpendicularly to the subchondral bone. This zone possesses the largest diameter collagen fibers and the highest concentration of proteoglycans.

Question 99

A 45-year-old female presents with severe pain over the medial eminence of her great toe. Radiographs demonstrate a Hallux Valgus Angle (HVA) of 45 degrees, an Intermetatarsal Angle (IMA) of 18 degrees, and clinical examination reveals marked hypermobility of the first tarsometatarsal (TMT) joint. Which of the following surgical procedures is most appropriate to provide durable correction?

Explanation

A severely elevated IMA (>15 degrees) combined with clinical hypermobility of the first tarsometatarsal joint is the classic indication for a Lapidus procedure (arthrodesis of the 1st TMT joint). Distal osteotomies are insufficient for high IMA angles and do not address the hypermobility.

Question 100

A 23-year-old male presents to the clinic with persistent "snuffbox" tenderness three months after a fall onto his extended wrist. Imaging confirms a non-union of the proximal pole of the scaphoid with early avascular necrosis. The vulnerability of the proximal pole to avascular necrosis is primarily due to the dominant arterial blood supply entering the scaphoid at which of the following locations?

Explanation

The scaphoid relies on retrograde blood flow for its proximal pole. The dominant vascular supply (accounting for 70-80% of the blood supply) enters via branches of the radial artery at the dorsal ridge, leaving proximal pole fractures highly susceptible to avascular necrosis and non-union.

Orthopedic Surgery Board Review MCQs: Arthroplasty, Trauma & Spine Part 255

Orthopedic Surgery Board Review MCQs: Foot & Ankle, Upper Extremity & Cartilage | Part 11

Key Takeaway

Orthopedic Surgery Board Review MCQs: Foot & Ankle, Upper Extremity & Cartilage | Part 11

Chapter Index