ABOS Part I Orthopedic Review: Elbow & Hand Trauma

Question 1

A 38-year-old male sustains a fall onto an outstretched hand, resulting in a radial head fracture. Initial radiographs are shown below. He is managed non-operatively with a sling for comfort and early range of motion. Six weeks later, he presents with persistent, worsening wrist pain, particularly with forearm rotation, and a feeling of instability at the distal radio-ulnar joint (DRUJ). On examination, there is tenderness over the DRUJ and a positive 'shuck test' at the wrist. A follow-up wrist radiograph reveals a positive ulnar variance (proximal migration of the radius). What is the most likely diagnosis?

Explanation

Correct Answer: C

The patient's presentation of a radial head fracture followed by persistent wrist pain, DRUJ instability (positive shuck test), and radiographic evidence of proximal radial migration (positive ulnar variance) is pathognomonic for an Essex-Lopresti lesion. This complex injury involves a radial head fracture, disruption of the interosseous membrane, and injury to the distal radio-ulnar joint. The radial head is crucial for longitudinal forearm stability, and its injury, combined with interosseous membrane disruption, allows the radius to migrate proximally, leading to DRUJ dysfunction. Radial head non-union would primarily cause elbow pain and might not explain the DRUJ instability and proximal migration. Chronic lateral epicondylitis is an overuse condition of the elbow extensors. Heterotopic ossification causes stiffness but not typically DRUJ instability. Carpal tunnel syndrome is a median nerve compression neuropathy and would present with different symptoms.

Question 2

A 58-year-old active construction worker presents with a Mason-Johnston Type III radial head fracture after a fall. Radiographs, as depicted below, show severe comminution with four distinct fragments involving approximately 60% of the articular surface. There is no associated elbow dislocation. He desires to return to full work capacity. Which of the following is the most appropriate surgical management to restore function and stability?

Explanation

Correct Answer: C

For a highly comminuted (Mason-Johnston Type III or IV) radial head fracture, especially in an active patient who desires a full return to function, radial head replacement is often the preferred surgical option. ORIF would be technically challenging or impossible with four fragments involving 60% of the articular surface, and stable fixation is unlikely. Radial head excision, while an option for low-demand patients, carries a significant risk of proximal radial migration and DRUJ instability, which would be detrimental to an active construction worker. Non-operative management is inappropriate for such a severely comminuted and displaced fracture. Primary elbow arthrodesis is a salvage procedure for end-stage arthritis or instability, not an acute fracture.

Question 3

During open reduction and internal fixation (ORIF) of a Mason-Johnston Type II radial head fracture, the surgeon plans to use headless compression screws. To minimize the risk of hardware impingement against the capitellum or ulna during forearm rotation, where is the ideal 'safe zone' for screw placement on the radial head?

Explanation

Correct Answer: C

The 'safe zone' for hardware placement in the radial head is a critical concept in ORIF to prevent impingement. This zone refers to the portion of the radial head that does not articulate with the capitellum of the humerus or the lesser sigmoid notch of the ulna through a full range of forearm pronation and supination. It is typically described as a 110-degree arc on the radial head, often corresponding to the posterolateral quadrant when the forearm is in neutral rotation. Placing hardware outside this zone can lead to pain, crepitus, and a mechanical block to motion, necessitating hardware removal. The other options describe articulating surfaces or specific quadrants that are not universally 'safe' throughout the entire range of motion.

Question 4

A 42-year-old female presents to the emergency department after a high-energy fall, sustaining a posterior elbow dislocation, a comminuted radial head fracture (Mason-Johnston Type IV), and a coronoid process fracture. After successful closed reduction of the elbow, radiographs are obtained, as shown below. What is the most critical ligamentous injury associated with this 'terrible triad' pattern that must be assessed and potentially addressed to ensure elbow stability?

Explanation

Correct Answer: C

The 'terrible triad' of the elbow consists of a posterior elbow dislocation, a radial head fracture, and a coronoid process fracture. This injury pattern is characterized by significant instability. The most consistently injured and critical ligament for posterolateral rotatory stability of the elbow in this context is the lateral ulnar collateral ligament (LUCL). Injury to the LUCL, often avulsed from its humeral origin, allows for posterolateral subluxation or dislocation of the ulna relative to the humerus. While the MCL can also be injured, and the annular ligament is disrupted with the radial head fracture, the LUCL is the key structure whose integrity dictates posterolateral rotatory stability and often requires repair or reconstruction in conjunction with radial head replacement and coronoid fixation.

Question 5

A 68-year-old female sustains a fall, resulting in a Mason-Johnston Type II radial head fracture. Radiographs, as shown below, demonstrate a single displaced fragment involving 35% of the articular surface with a 3mm step-off. Clinically, she has a palpable mechanical block to terminal forearm pronation and supination. What is the most appropriate initial management strategy?

Explanation

Correct Answer: B

A Mason-Johnston Type II radial head fracture with a mechanical block to forearm rotation, even with moderate displacement, is a strong indication for surgical intervention. The mechanical block signifies impingement of the displaced fragment, which will prevent full range of motion and lead to chronic dysfunction if not addressed. For a single, displaced fragment, open reduction and internal fixation (ORIF) is the preferred treatment to restore articular congruity and eliminate the mechanical block. Sling immobilization alone is insufficient. Radial head excision is generally reserved for severely comminuted fractures not amenable to ORIF or in low-demand patients, and carries risks of proximal radial migration. Radial head replacement is typically indicated for highly comminuted (Type III/IV) fractures or in cases of associated instability (e.g., Essex-Lopresti, terrible triad). Attempting closed reduction is unlikely to succeed with a palpable block from a displaced articular fragment.

Question 6

A 29-year-old male presents with a radial head fracture after a motorcycle accident. Initial radiographs are shown below. While the elbow appears stable, the surgeon is concerned about potential associated injuries that are frequently missed in the initial evaluation. Which of the following associated injuries is *most* commonly missed in the initial evaluation of an isolated radial head fracture?

Explanation

Correct Answer: D

While all listed injuries can occur with radial head fractures, distal radio-ulnar joint (DRUJ) instability, often indicative of an Essex-Lopresti lesion, is frequently missed in the initial evaluation. It may not be immediately apparent on elbow radiographs and can present insidiously with wrist pain and instability days or weeks after the initial injury. A high index of suspicion and careful examination of the wrist, along with ipsilateral wrist radiographs (looking for proximal radial migration), are crucial. Coronoid and MCL injuries are typically associated with elbow dislocations (e.g., terrible triad) and are usually more obvious. Capitellum chondral injuries are less common and often require advanced imaging or arthroscopy. Olecranon fractures are usually clearly visible on initial X-rays.

Question 7

A 72-year-old sedentary patient presents with a Mason-Johnston Type III radial head fracture with severe comminution, as shown in the radiographs below. She has significant comorbidities and is not a candidate for a lengthy or complex surgical procedure. She desires pain relief and improved elbow motion for basic activities of daily living. What is a reasonable management option to consider, accepting potential trade-offs?

Explanation

Correct Answer: C

For elderly, sedentary patients with severely comminuted radial head fractures (Type III or IV) who are not candidates for ORIF (due to comminution or bone quality) or do not desire more extensive surgery like radial head replacement (due to comorbidities or complexity), radial head excision can be a reasonable option. While it carries the risk of proximal radial migration and DRUJ issues, in low-demand individuals, it can provide pain relief and improve motion with acceptable functional outcomes. ORIF is often not feasible due to comminution. Replacement is a good option but more involved surgery. Arthrodesis is a salvage procedure. Long arm casting would likely lead to severe stiffness in this age group and is generally avoided for radial head fractures.

Question 8

A 45-year-old male undergoes open reduction and internal fixation (ORIF) of a Mason-Johnston Type II radial head fracture. Two weeks post-operatively, he complains of persistent elbow pain, stiffness, and crepitus, particularly with forearm rotation, despite diligent physical therapy. Radiographs, shown below, confirm stable fixation with no obvious loosening. What is the most common cause of *early* post-operative stiffness and pain in this scenario?

Explanation

Correct Answer: C

Early post-operative stiffness, pain, and crepitus following radial head fracture fixation are very commonly caused by hardware prominence and impingement. If screws or plates are not properly countersunk or are placed outside the 'safe zone' (the non-articulating portion of the radial head), they can impinge on the capitellum or the lesser sigmoid notch of the ulna during elbow flexion-extension or forearm rotation. This mechanical impingement causes pain and restricts range of motion. While infection, nerve injury, and non-union are possible complications, hardware impingement is a leading cause of early stiffness directly related to the fixation itself. Aseptic loosening is typically a later complication.

Question 9

A 32-year-old female presents with a Mason-Johnston Type I radial head fracture after a low-energy fall. Radiographs, as shown below, reveal a non-displaced crack in the radial head with no articular step-off. On examination, she has mild pain but full, pain-free forearm pronation and supination. What is the most appropriate initial management strategy?

Explanation

Correct Answer: C

Mason-Johnston Type I radial head fractures are characterized by a non-displaced crack or minimal displacement (less than 2mm) without a mechanical block to forearm rotation. For these injuries, non-operative management is the standard of care. This typically involves a brief period of immobilization (e.g., a few days to 1 week in a sling for comfort) followed by early active range of motion exercises. Prolonged immobilization, such as a long arm cast, should be avoided as it significantly increases the risk of elbow stiffness, a common and debilitating complication. Surgical interventions like ORIF, radial head replacement, or excision are not indicated for Type I fractures.

Question 10

What is the primary role of the radial head in the biomechanics and stability of the elbow and forearm?

Explanation

Correct Answer: C

The radial head plays two crucial roles in elbow and forearm stability. Firstly, it acts as a secondary stabilizer against valgus stress at the elbow, providing a bony buttress, especially when the primary valgus stabilizer (the anterior bundle of the medial collateral ligament) is compromised. Secondly, and critically, it provides longitudinal stability to the forearm, maintaining the length relationship between the radius and ulna. This longitudinal stability is essential for proper distal radio-ulnar joint (DRUJ) mechanics and overall forearm function. While it articulates to allow pronation/supination, its primary role in *stability* is as a secondary valgus stabilizer and longitudinal load bearer. The biceps attaches to the radial tuberosity, not the head itself. The coronoid process and olecranon prevent posterior dislocation of the ulna.

Question 11

A 45-year-old male sustains a comminuted distal humerus fracture involving both columns and the articular surface (AO 13-C3) after a fall from a height. Clinically, he has significant swelling, pain, and a palpable ulnar nerve neuropraxia. Radiographs confirm the diagnosis, and a CT scan reveals severe comminution. Which of the following surgical approaches is generally considered the workhorse for achieving adequate exposure for anatomical reduction and stable fixation of such a fracture?

Explanation

Correct Answer: D

For complex, comminuted intra-articular distal humerus fractures (AO 13-C3), a posterior approach with an olecranon osteotomy (e.g., Chevron osteotomy) provides the most extensive and direct visualization of the entire distal humeral articular surface and both columns. This allows for precise anatomical reduction of articular fragments and robust plate application, which is critical for restoring elbow function and minimizing post-traumatic arthritis. While triceps-sparing approaches are gaining popularity, they often provide less complete visualization for severely comminuted intra-articular fractures, making anatomical reduction more challenging. Anterior, medial, and lateral approaches are typically reserved for specific fracture patterns (e.g., isolated capitellar or trochlear fractures) or for less complex supracondylar fractures.

Question 12

Regarding the surgical fixation of a complex intra-articular distal humerus fracture, such as the one shown in the CT reconstruction, what is the most biomechanically stable construct for dual plating?

Explanation

Correct Answer: C

Orthogonal plating, typically with a medial plate and a posterior or posterolateral plate, creates a more stable construct biomechanically than parallel plating. This configuration provides support against both valgus/varus and torsional forces, acting as a '90-90' system (relative to each other, not the bone's long axis). This multiplanar stability is crucial for complex, comminuted fractures to allow early range of motion. Parallel plating (two plates on the medial and lateral columns) is also a strong construct, particularly for stabilizing the columns, but biomechanical studies often show orthogonal plating to be superior in complex fractures due to better load distribution and resistance to displacement. Posterior plates alone or anterior plates are insufficient for complex intra-articular fractures.

Question 13

During the surgical exposure for a distal humerus fracture via a posterior approach, which anatomical structure is at highest risk of iatrogenic injury, particularly during posteromedial dissection and mobilization?

Explanation

Correct Answer: D

The ulnar nerve is the most vulnerable neurological structure during posterior approaches to the distal humerus. It courses through the cubital tunnel posterior to the medial epicondyle and is often directly exposed, mobilized, and protected (often transposed anteriorly) during complex distal humerus fracture fixation to prevent iatrogenic injury or secondary compression. The radial nerve is at risk more proximally in the humeral shaft or during lateral approaches. The median nerve and brachial artery are anterior and generally protected by muscle bellies. The musculocutaneous nerve is even further anterior and lateral, making it less susceptible during a posterior approach.

Question 14

Following open reduction and internal fixation (ORIF) of a severely comminuted intra-articular distal humerus fracture in a 68-year-old osteoporotic patient, what is the most common early complication directly related to the fixation construct in this patient population?

Explanation

Correct Answer: D

In osteoporotic patients, the primary concern for early complication after ORIF of a comminuted distal humerus fracture is hardware pull-out or failure. Poor bone quality provides inadequate purchase for screws, leading to loss of reduction and implant failure. This necessitates specific techniques like locking plates, longer screws, and sometimes bone augmentation (e.g., cement augmentation). Nonunion and heterotopic ossification are typically later complications. Infection is a risk but not specifically heightened by osteoporosis itself. Ulnar nerve palsy is a risk from the surgery but not directly related to implant mechanics in osteoporotic bone.

Question 15

A 32-year-old presents with a displaced intra-articular distal humerus fracture (AO 13-C1). Initial assessment reveals a healthy patient with no neurovascular deficits. What is the most appropriate next step in management after initial stabilization and plain radiographs?

Explanation

Correct Answer: C

While surgical fixation is likely indicated for a displaced intra-articular fracture, a CT scan with 3D reconstructions is crucial for operative planning. Plain radiographs often underestimate the degree of articular comminution and displacement, especially for complex intra-articular patterns. The CT scan provides detailed information about fragment size, location, and the extent of articular involvement, which guides the choice of surgical approach and fixation strategy. Immediate ORIF without CT is suboptimal. A cast is inappropriate for displaced intra-articular fractures in an active patient, and immediate ROM is contraindicated pre-operatively. Antibiotics are not indicated unless an open fracture is suspected.

Question 16

What is the primary role of the olecranon osteotomy in the surgical management of complex distal humerus fractures?

Explanation

Correct Answer: C

The primary advantage of an olecranon osteotomy is to provide a wide, direct, and panoramic surgical exposure of the entire distal humeral articular surface and both columns. This enables accurate anatomical reduction of often numerous small articular fragments under direct vision, which is paramount for restoring elbow function and minimizing post-traumatic arthritis. While an ulnar nerve decompression can be performed concomitantly, it's not the primary role of the osteotomy. The osteotomy itself is a separate fracture that requires fixation and has its own potential complications, and it doesn't directly prevent HO or shorten overall healing time.

Question 17

A 75-year-old female with severe osteoporosis sustains a highly comminuted distal humerus fracture (AO 13-C3) with significant bone loss. She has a low functional demand but is medically fit for surgery. What surgical option might be considered in this specific scenario, even if ORIF is technically possible but challenging to achieve stable fixation?

Explanation

Correct Answer: B

For elderly, osteoporotic patients with highly comminuted distal humerus fractures where stable ORIF is unlikely to be achieved, or if stable fixation will not allow early motion, Total Elbow Arthroplasty (TEA) is an increasingly accepted option, particularly in patients with low functional demands. It allows for immediate stability and early motion, which is critical in this population to prevent stiffness and achieve early functional recovery. Functional bracing is unlikely to yield a good result with a highly comminuted, unstable fracture. Elbow fusion would be highly disabling for a low-demand patient. Excision arthroplasty is rarely performed today due to poor outcomes. Hemiarthroplasty of the distal humerus is not a standard procedure for complex distal humerus fractures due to the articulation challenges with the native ulna and radius.

Question 18

Following ORIF of a distal humerus fracture, a patient develops severe progressive elbow stiffness despite successful fracture healing confirmed by radiographs. What is the most common cause of this complication after successful fracture healing?

Explanation

Correct Answer: B

Post-traumatic heterotopic ossification (HO) is a common cause of severe elbow stiffness after distal humerus fractures and their surgical treatment, even after successful fracture healing. It involves the formation of mature lamellar bone in soft tissues where bone does not normally exist, which can restrict motion significantly. While nonunion can cause pain and instability, it doesn't directly cause stiffness in the same way HO does. Ulnar nerve entrapment typically causes paresthesia and weakness, not direct mechanical stiffness. Chronic infection is possible but less common than HO. Radial head subluxation is not a typical complication leading to global stiffness after a distal humerus fracture.

Question 19

A 40-year-old male presents to the emergency department with a distal humerus fracture. Upon examination, there is a 3 cm laceration over the medial aspect of the elbow, communicating with the fracture site. Which of the following is an absolute indication for surgical intervention in this distal humerus fracture?

Explanation

Correct Answer: A

An open fracture is an absolute indication for emergent surgical débridement and fixation due to the high risk of infection and subsequent devastating complications. Neurovascular deficits, especially an acute deficit following injury, often warrant emergent exploration but can sometimes be observed if a neuropraxia is suspected without overt vascular compromise. Intra-articular displacement > 2mm is a strong indication for ORIF but is generally considered a relative indication (compared to an open fracture). Age > 65 years is a patient factor, not a fracture characteristic dictating surgery. An associated olecranon fracture is a complex injury but not an absolute indication in itself compared to an open fracture.

Question 20

A 55-year-old male undergoes ORIF of a distal humerus fracture. Six hours post-operatively, he develops severe pain in the forearm, swelling, and bullae around the elbow. He reports pain out of proportion to the injury and analgesia. What is the most appropriate initial management step to prevent catastrophic complications?

Explanation

Correct Answer: B

Severe pain, swelling, and bullae post-operatively, especially pain out of proportion to the injury, are highly concerning for evolving compartment syndrome, particularly in the forearm. Immediate release of all constrictive dressings (splints, casts, bandages) is paramount. If suspicion remains high or objective signs (e.g., pain with passive stretch of digits, paresthesia, tense compartments) are present, emergent fasciotomy is indicated to prevent irreversible ischemic damage to muscles and nerves. While elevation is good, and antibiotics might be considered later if infection is suspected, the immediate life-altering threat is compartment syndrome. Ultrasound for DVT is not relevant to acute swelling and pain in this context, and hot packs would worsen swelling.

Question 21

A 19-year-old basketball player presents with a suspected Jersey finger of his small finger. On examination, he has full active flexion of his PIP joint but lacks active flexion of his DIP joint. A modified tabletop test reveals a normal cascade for all fingers except the small finger, which remains extended at the DIP joint. What is the most reliable maneuver to confirm an FDP rupture in this digit?

Explanation

Correct Answer: C

The most reliable maneuver to confirm an FDP rupture is to isolate the action of the FDP tendon. This is done by stabilizing the PIP joint in full extension and asking the patient to actively flex the DIP joint. If the FDP is ruptured, active DIP flexion will be absent. Assessing passive range of motion will typically be full, as the FDP rupture is an active deficit. Palpating a tender gap can be indicative but is not always reliable, especially with swelling. Grip strength is a global measure and not specific enough. Finkelstein's test is for De Quervain's tenosynovitis and is irrelevant in this context.

Question 22

A 24-year-old rugby player presents 48 hours after sustaining an injury to his left ring finger while tackling an opponent. He reports his finger was forcibly extended while he was gripping the opponent's jersey. On examination, he has swelling and tenderness over the palmar aspect of the distal phalanx. He is unable to actively flex the DIP joint of the ring finger. The remaining fingers show normal cascade. Passive DIP flexion is full. X-rays show no bony avulsion. Which of the following Leddy and Packer types is most likely, and what is the primary concern driving urgent treatment?

Explanation

Correct Answer: C

This scenario describes a classic Type I Jersey finger. A Type I injury involves rupture of the FDP tendon without a bony avulsion, and the tendon typically retracts into the palm, losing its vincula blood supply. The primary concern driving the urgency for repair (ideally within 7-10 days, but sooner if possible) is the preservation of the tendon's intrinsic vascularity to prevent necrosis and facilitate healing. Type II also lacks a bony avulsion but the tendon is retained at the A3 pulley level, often with intact vincula, making it less urgent than Type I. Type III involves a bony avulsion fragment, which prevents further retraction and maintains tendon blood supply, making it less urgent. Type IV involves an avulsed bone fragment with the tendon avulsed from the fragment, and Type V involves an intra-articular fracture with tendon avulsion; these are also distinct from the given scenario.

Question 23

Which of the following anatomical structures is MOST critical for providing blood supply to the flexor digitorum profundus (FDP) tendon in the distal finger, particularly relevant in Type I Jersey finger injuries?

Explanation

Correct Answer: C

The vincula tendinum are mesotendinous structures that connect the flexor tendons to the phalanges and provide the primary blood supply to the tendons within the flexor sheath. In a Type I Jersey finger, the FDP tendon avulses distal to the vincula longa and retracts into the palm, often stripping it of its vincula and thus its blood supply, leading to a high risk of tendon necrosis. The A2 pulley is a critical mechanical structure but not primarily a source of blood supply to the tendon itself. The flexor sheath provides an environment, not the primary blood supply. Annular ligaments are the pulleys. Lumbrical muscles have their own blood supply but do not supply the FDP tendon directly.

Question 24

When performing a primary repair of a retracted FDP tendon, which of the following is considered the gold standard suture technique for strength and preventing pull-out?

Explanation

Correct Answer: D

The gold standard for flexor tendon repair involves a strong core suture technique that provides robust mechanical strength against gapping and pull-out. The Modified Kessler (or similar variations like Lim-Tsai, Modified Becker, Pennington) is a common and effective core suture. An epitendinous suture is typically used in addition to a core suture to create a smooth gliding surface and add some strength, but it is not sufficient on its own for primary repair strength. Simple interrupted, horizontal mattress, and running locking sutures are not typically used as primary core sutures in flexor tendon repair due to lower strength and potential for gapping or strangulation.

Question 25

Which of the following statements most accurately describes the 'quadriga effect' as a potential complication following FDP repair, particularly when using advancement techniques?

Explanation

Correct Answer: A

The quadriga effect is a well-known complication of FDP repair, particularly when the tendon is shortened (e.g., through advancement or overtightening during repair). Because the FDP tendons of the medial four fingers share a common muscle belly (or are closely intertwined proximally), overtensioning of one FDP tendon will restrict full flexion of the adjacent, healthy FDP tendons. This results in the inability of the adjacent digits to fully flex. The other options describe different complications or aspects of tendon repair.

Question 26

What is the typical presentation of a 'lumbrical plus' phenomenon, which can be a complication of FDP repair or shortening?

Explanation

Correct Answer: B

The 'lumbrical plus' phenomenon occurs when the FDP tendon is advanced and overtensioned, or the repair site is too stiff, causing the lumbrical muscle to be pulled proximally. When the patient attempts to flex the finger (activating the FDP), the lumbrical is put under tension before the FDP can flex the DIP joint. Since the lumbrical inserts into the extensor mechanism, its contraction paradoxically extends the DIP joint instead of allowing FDP flexion. This results in the DIP joint extending or remaining extended when the patient attempts to make a full fist. Option E describes the quadriga effect.

Question 27

Regarding the surgical repair of a chronic FDP rupture (presenting 6 months post-injury) in a 35-year-old manual laborer, which of the following is the most appropriate initial management strategy if direct primary repair is not feasible?

Explanation

Correct Answer: C

For chronic FDP ruptures where direct primary repair is not feasible due to significant tendon retraction and shortening, staged tendon reconstruction using a silicone rod (Hunter rod) is often the preferred strategy. The silicone rod creates a pseudosheath, which then facilitates the passage of an autogenous tendon graft (commonly palmaris longus or plantaris) in a second stage. FDP advancement is only feasible for gaps typically less than 1 cm. Delayed primary repair with an interpositional graft is a possibility, but less predictable than staged reconstruction for significant gaps. Amputation is overly aggressive, and observation alone will not restore function in a chronic rupture.

Question 28

A patient undergoes FDP repair for a Jersey finger. The post-operative protocol involves early active motion. What is the primary rationale behind initiating early active motion protocols for flexor tendon repairs?

Explanation

Correct Answer: D

The primary rationale for early active motion protocols after flexor tendon repair is to promote tendon gliding and prevent the formation of restrictive adhesions within the flexor sheath. Controlled motion helps to maintain the gliding surface between the tendon and the surrounding tissues, which is crucial for achieving a good functional outcome and full range of motion. While it may indirectly help with swelling and muscle atrophy, its main goal is to optimize tendon healing and prevent adhesions, which is a major cause of post-operative stiffness.

Question 29

During surgical repair of a Jersey finger, care must be taken to preserve the flexor pulley system. Which two pulleys are considered the most critical to maintain for optimal flexor tendon function and to prevent bowstringing?

Explanation

Correct Answer: B

The A2 and A4 pulleys are considered the most critical annular pulleys for maintaining the mechanical efficiency of the flexor tendons and preventing bowstringing. The A2 pulley is located over the proximal phalanx, and the A4 pulley is over the middle of the distal phalanx. Their integrity is paramount for normal finger flexion biomechanics. Damage to these pulleys significantly compromises the tendon's leverage and function.

Question 30

A 45-year-old professional pianist sustains a Jersey finger (Type I) of his long finger. He presents 6 weeks post-injury. What is the most appropriate treatment option at this delayed presentation?

Explanation

Correct Answer: D

At 6 weeks, a Type I Jersey finger is considered a chronic injury. Significant tendon retraction and shortening would have occurred, making direct primary repair or FDP advancement (which is typically for gaps <1cm) impossible without excessive tension leading to quadriga or re-rupture. Therefore, staged tendon reconstruction using a silicone rod followed by a tendon graft is the most appropriate option to reconstruct the flexor mechanism and restore function. Non-operative management will not restore active DIP flexion. Amputation is a last resort.

Question 31

A 45-year-old male sustains a 'terrible triad' injury of the elbow following a fall. According to standard surgical protocols, what is the most appropriate sequence of repair after exposing the joint?

Explanation

The standard surgical sequence for a terrible triad injury involves addressing the structures from deep to superficial: fixing the coronoid, fixing or replacing the radial head, and finally repairing the lateral collateral ligament (LCL). If instability persists after these steps, the MCL or a hinged external fixator may be considered.

Question 32

During the primary repair of a Zone II flexor tendon laceration, a surgeon elects to use a multi-strand core suture technique. Which of the following factors is most critical in minimizing gap formation at the repair site during early active rehabilitation?

Explanation

The biomechanical strength and resistance to gap formation in a flexor tendon repair are most directly correlated with the number of core suture strands crossing the repair site and adequate core purchase length. Epitendinous sutures further increase repair strength and smooth the gliding surface.

Question 33

A 24-year-old male presents with a scaphoid proximal pole fracture nonunion. The proximal pole is at high risk for avascular necrosis due to its retrograde blood supply. Which of the following vessels is the primary source of this retrograde perfusion?

Explanation

The scaphoid receives its primary blood supply from the dorsal carpal branch of the radial artery, which enters the dorsal ridge distally and supplies the proximal pole in a retrograde fashion. This vulnerable vascular anatomy highly predisposes proximal pole fractures to nonunion and avascular necrosis.

Question 34

A 28-year-old boxer sustains a Bennett fracture. Radiographs demonstrate that the main metacarpal shaft is displaced proximally, dorsally, and radially. Which muscle is primarily responsible for this specific deforming force on the metacarpal shaft?

Explanation

In a Bennett fracture, the abductor pollicis longus (APL) pulls the metacarpal shaft proximally, dorsally, and radially. The adductor pollicis exerts a supinating and ulnar-directed force on the distal metacarpal, while the volar ulnar beak fragment remains tethered by the anterior oblique ligament.

Question 35

A 30-year-old rugby player presents with an inability to actively flex the distal interphalangeal (DIP) joint of his ring finger. MRI demonstrates a flexor digitorum profundus (FDP) avulsion retracted completely into the palm. Within what maximum timeframe should this specific injury ideally be surgically repaired to prevent permanent tendon retraction and necrosis?

Explanation

This describes a Leddy and Packer Type I FDP avulsion (Jersey finger), where the tendon retracts into the palm, disrupting both the long and short vincula. It requires surgical repair within 7-10 days before the tendon undergoes contracture and ischemic necrosis.

Question 36

A 45-year-old male sustains a 'terrible triad' injury of the elbow (dislocation, coronoid fracture, and radial head fracture). During operative management, what is the most widely accepted standard surgical sequence for reconstruction?

Explanation

The standard surgical algorithm for a terrible triad injury works from deep to superficial and medial to lateral: fix the coronoid first, address the radial head (fixation or arthroplasty), and finally repair the LCL complex to restore posterolateral stability. The MCL is rarely repaired unless instability persists after addressing the other three components.

Question 37

A 25-year-old chef sustains a knife laceration to the volar aspect of the proximal phalanx, transecting both the FDS and FDP tendons. To safely allow an early active motion protocol following Zone II flexor tendon repair, what is the minimum recommended number of core suture strands crossing the repair site?

Explanation

Biomechanical studies have consistently demonstrated that a 4-strand core suture technique provides the minimum tensile strength required to safely withstand the forces of early active motion protocols. A 2-strand repair is generally considered too weak and carries a higher risk of rupture with active flexion.

Question 38

A 32-year-old female sustains a coronal shear fracture of the distal humerus that involves the capitellum and the majority of the trochlea. According to the Bryan and Morrey classification with McKee modification, what type is this fracture, and what is the optimal surgical approach?

Explanation

The McKee modification (Type IV) describes a coronal shear fracture extending medially to involve the capitellum and most of the trochlea. To adequately visualize and fix both the capitellum and trochlear fragments, an extensile lateral approach or a posterior approach with an olecranon osteotomy is required.

Question 39

A 28-year-old male presents with advanced SNAC (Scaphoid Nonunion Advanced Collapse) wrist, classified as Stage III (involving radioscaphoid and capitolunate arthritis, but sparing the radiolunate joint). Which of the following is the most appropriate surgical intervention?

Explanation

Stage III SNAC wrists involve arthritis at both the radioscaphoid and capitolunate joints, while the radiolunate joint remains preserved. Four-corner fusion with scaphoid excision relies on the preserved radiolunate joint, whereas PRC is contraindicated because the capitate head (which would articulate with the lunate fossa) is already arthritic.

Question 40

An untreated closed disruption of the extensor tendon central slip at the proximal interphalangeal (PIP) joint will most likely progress to a Boutonniere deformity. Which biomechanical sequence accurately describes the pathogenesis of this deformity?

Explanation

A central slip rupture allows the lateral bands to subluxate volarly to the axis of rotation of the PIP joint, converting them into PIP flexors. Their continued pull on the distal phalanx simultaneously causes hyperextension of the DIP joint, creating the classic Boutonniere deformity.

Question 41

A 21-year-old rugby player sustains a 'Jersey finger' injury, avulsing the flexor digitorum profundus (FDP) tendon of the ring finger. Imaging reveals no fracture, but ultrasound shows the tendon retracted completely into the palm. According to the Leddy and Packer classification, what type is this injury, and what is the status of the vincular blood supply?

Explanation

Leddy and Packer Type I injuries involve an FDP tendon that retracts into the palm, rupturing both the vincula brevis and longus, severely compromising its blood supply. These injuries require urgent repair (typically within 7-10 days) before the tendon undergoes permanent ischemic contracture.

Question 42

A 65-year-old male presents with a highly comminuted, displaced olecranon fracture that extends distally toward the coronoid process. Which of the following fixation constructs is most biomechanically appropriate and carries the lowest rate of hardware failure for this specific fracture pattern?

Explanation

Bridge plating with a pre-contoured locking plate provides superior stability for comminuted olecranon fractures, preventing the shortening and collapse that often occur with compression techniques. Tension band wiring is contraindicated in comminuted fractures because it relies on anterior cortical contact to convert tensile forces into compressive forces.

Question 43

During open reduction and internal fixation of a Galeazzi fracture-dislocation, after anatomic rigid plating of the radius, the distal radioulnar joint (DRUJ) remains irreducible. Which of the following anatomic structures is most commonly blocking reduction?

Explanation

An irreducible DRUJ following anatomic fixation of the radius in a Galeazzi fracture is most often caused by soft tissue interposition. The extensor carpi ulnaris (ECU) tendon is the most common offending structure, frequently becoming entrapped in the ulnar notch.

Question 44

A 35-year-old male sustains a proximal ulna shaft fracture with an associated anterior dislocation of the radial head. According to the Bado classification, what type of Monteggia fracture is this, and what is the standard operative management?

Explanation

Bado Type I describes a proximal ulna fracture with anterior dislocation of the radial head, the most common type. In adults, the standard of care is anatomic ORIF of the ulna, which typically results in spontaneous, stable closed reduction of the radial head.

Question 45

A 42-year-old diabetic patient presents with a swollen, acutely painful index finger. Which of the following is considered the most reliable, earliest, and most sensitive Kanavel sign for diagnosing purulent flexor tenosynovitis?

Explanation

While all four Kanavel signs indicate purulent flexor tenosynovitis, pain with passive extension is recognized as the earliest and most sensitive sign. The inflammation of the sheath causes exquisite pain when the tendon is stretched by passive finger extension.

Question 46

A 40-year-old mechanic complains of chronic dorsal wrist pain. Radiographs demonstrate a scapholunate gap of 4 mm, a 'cortical ring sign', and narrowing of the radioscaphoid articulation, while the midcarpal joint is preserved. This radiographic pattern is most consistent with which stage of Scapholunate Advanced Collapse (SLAC)?

Explanation

SLAC staging follows a predictable pattern of arthritic progression. Stage I involves the radial styloid; Stage II involves the entire radioscaphoid fossa; and Stage III progresses to involve the capitolunate joint. The midcarpal joint is preserved here, placing it in Stage II.

Question 47

When utilizing the standard volar approach (modified Henry) for open reduction and internal fixation of a distal radius fracture, the surgeon initially develops an interval between which two structures to safely access the deeper pronator quadratus?

Explanation

The modified Henry approach utilizes the internervous plane between the median nerve (supplying FCR) and the radial nerve (supplying brachioradialis). Superficially, the surgeon develops the interval between the FCR tendon and the radial artery to safely retract the neurovascular structures.

Question 48

In a Bennett fracture of the thumb metacarpal base, what muscle is primarily responsible for the proximal and dorsal displacement of the main metacarpal shaft fragment?

Explanation

In a Bennett fracture, the volar-ulnar beak fragment remains attached to the anterior oblique ligament. The main metacarpal shaft fragment is displaced proximally, dorsally, and radially by the strong pull of the abductor pollicis longus (APL) tendon.

Question 49

A 45-year-old female presents with an elbow injury after a fall. Radiographs and CT show a coronal shear fracture of the capitellum extending into the lateral ridge of the trochlea, with posterior comminution. According to the Dubberley classification, what is the best surgical approach and fixation strategy?

Explanation

This is a Dubberley Type 3B fracture (involving capitellum and trochlea with posterior comminution). Posterior comminution dictates the need for posterior buttress plating to prevent displacement, typically requiring an extensile lateral or posterior approach.

Question 50

During the repair of a Zone II flexor tendon injury, the surgeon considers the number of core suture strands. Which of the following best describes the biomechanical relationship between the number of core strands and the repair characteristics?

Explanation

Increasing the number of core suture strands increases the ultimate tensile strength of the repair, which is beneficial for early active motion. However, it also increases the bulk of the repair, significantly increasing gliding resistance and the work of flexion.

Question 51

A 30-year-old male sustains a dorsal fracture-dislocation of the PIP joint. Radiographs show a volar lip fracture involving 45% of the articular surface of the middle phalanx. The joint is unstable on extension block splinting at 30 degrees. What is the most appropriate definitive management?

Explanation

For unstable dorsal PIP fracture-dislocations involving greater than 40% of the volar articular surface, joint reconstruction via volar plate arthroplasty, hemihamate autograft, or dynamic external fixation is indicated to restore stability and congruity.

Question 52

In the surgical management of a 'terrible triad' injury of the elbow (elbow dislocation, radial head fracture, coronoid fracture), what is the generally accepted and most biomechanically sound sequence of reconstruction?

Explanation

The standard deep-to-superficial approach to the terrible triad involves fixing structures from inside out: first the coronoid, then the radial head (fixation or arthroplasty), and finally repairing the lateral collateral ligament (LCL) complex.

Question 53

A 22-year-old rugby player grabs an opponent's jersey and feels a pop in his ring finger. He cannot actively flex the distal interphalangeal (DIP) joint. Imaging shows no fracture, and the flexor digitorum profundus (FDP) tendon is palpable in the palm. What is the optimal timing and treatment?

Explanation

This is a Type 1 Jersey finger (FDP retracted into the palm), compromising its vascular supply from the vincula. It requires early surgical repair within 7-10 days to prevent permanent myostatic contracture and tendon necrosis.

Question 54

During open reduction and internal fixation of a distal third radial shaft fracture (Galeazzi fracture), the surgeon assesses the distal radioulnar joint (DRUJ) for instability. Which of the following intraoperative findings most strongly indicates the need for DRUJ stabilization?

Explanation

Following rigid fixation of the radius in a Galeazzi fracture, the DRUJ must be assessed. Gross instability in neutral or all forearm positions dictates the need for DRUJ stabilization, typically via radioulnar pinning in supination or open TFCC repair.

Question 55

A 25-year-old male punches a wall and sustains a closed fracture of the fifth metacarpal neck. Which of the following represents the maximum acceptable volar angulation for this fracture to be treated non-operatively with expected good functional outcome?

Explanation

The fifth metacarpal neck (Boxer's fracture) can tolerate up to 70 degrees of volar angulation due to the compensatory mobility of the 5th carpometacarpal (CMC) joint. Greater angulation, or any significant malrotation, requires reduction.

Question 56

A 30-year-old male sustains a Bennett fracture of the thumb base. The main fracture fragment is small and remains attached to the anterior oblique ligament. Which muscle is primarily responsible for the proximal, dorsal, and radial displacement of the first metacarpal shaft?

Explanation

In a Bennett fracture, the abductor pollicis longus (APL) pulls the metacarpal shaft proximally, dorsally, and radially. The small volar ulnar fragment remains held in its anatomic position by the anterior oblique ligament.

Question 57

Which of the following is an absolute indication for operative intervention in an acute scaphoid waist fracture?

Explanation

Displacement of greater than 1 mm in an acute scaphoid fracture is an absolute indication for surgical fixation due to the high risk of nonunion and subsequent Scaphoid Nonunion Advanced Collapse (SNAC). Proximal pole fractures are a strong relative indication.

Question 58

A patient develops a Boutonniere deformity 4 weeks after suffering a volar PIP joint dislocation. Which of the following best describes the underlying pathomechanics of this deformity?

Explanation

A Boutonniere deformity is characterized by PIP flexion and DIP extension. It is caused by rupture or attenuation of the central slip, allowing the lateral bands to subluxate volarly to the PIP joint axis of rotation, acting as PIP flexors and DIP extensors.

Question 59

A 35-year-old avid golfer presents with chronic ulnar-sided wrist pain and weakness in grip strength. Examination reveals localized tenderness over the hypothenar eminence. If left untreated, a nonunion of the suspected fracture most commonly puts which of the following tendons at risk of spontaneous rupture?

Explanation

A nonunion of a hook of the hamate fracture can lead to chronic friction and subsequent spontaneous rupture of the adjacent flexor tendons, most commonly the flexor digitorum profundus (FDP) to the small finger.

Question 60

A 60-year-old male undergoes tension band wiring for a displaced transverse olecranon fracture. Six months postoperatively, the fracture has healed, but he complains of pain at the posterior elbow. What is the most common complication associated with this specific surgical technique?

Explanation

The most common complication of tension band wiring for olecranon fractures is symptomatic prominent hardware, reported in up to 40-80% of patients. This frequently necessitates a secondary procedure for hardware removal.

Question 61

A 45-year-old female presents after falling on an outstretched hand. She is diagnosed with a 'terrible triad' injury of the elbow. Operative intervention is planned. According to standard treatment protocols (e.g., Pugh and Ring), what is the most widely recommended sequence of surgical reconstruction to restore elbow stability?

Explanation

The standard surgical algorithm for a terrible triad injury progresses from deep to superficial and typically from lateral to medial. The sequence is coronoid fixation, radial head repair or replacement, LCL complex repair, and finally MCL repair or hinged external fixation if the elbow remains unstable.

Question 62

A 35-year-old male undergoes a two-incision repair of a complete distal biceps tendon rupture. Six months postoperatively, he complains of a severe limitation in forearm rotation. Radiographs demonstrate a radioulnar synostosis. Which specific intraoperative maneuver during the surgical approach is most strongly associated with this complication?

Explanation

Radioulnar synostosis is a known complication of the two-incision (Boyd) approach for distal biceps repair. It is most commonly caused by subperiosteal elevation of the supinator and stripping of the proximal ulna, which triggers heterotopic ossification bridging the radius and ulna.

Question 63

A 32-year-old male presents with progressive wrist pain 5 years after an untreated scaphoid fracture. Radiographs reveal radioscaphoid arthritis and capitolunate arthritis, but the radiolunate joint is preserved. Based on the Scaphoid Nonunion Advanced Collapse (SNAC) staging, what is the most appropriate surgical treatment?

Explanation

This patient has Stage III SNAC wrist, characterized by arthritis extending to the capitolunate joint while sparing the radiolunate joint. Scaphoid excision and four-corner fusion is the treatment of choice, whereas proximal row carpectomy is contraindicated due to capitate articular wear.

Question 64

A 25-year-old mechanic sustains a volar laceration to his index finger at the level of the proximal phalanx, resulting in complete transection of the FDP and FDS tendons (Zone II). During surgical repair, what biomechanical factor is most directly responsible for increasing the tensile strength of the repair to safely allow early active motion?

Explanation

The tensile strength of a flexor tendon repair is directly proportional to the number of core suture strands crossing the repair site. A 4-strand or 6-strand repair provides significantly more strength than a 2-strand repair, making it robust enough to withstand the forces of early active motion protocols.

Question 65

A 30-year-old skier presents with acute ulnar-sided pain at the thumb metacarpophalangeal (MCP) joint after falling with a ski pole. Ultrasound confirms a completely displaced rupture of the ulnar collateral ligament (UCL), diagnosing a Stener lesion. What specific anatomical structure interposes between the torn UCL and its insertion site, preventing spontaneous healing?

Explanation

A Stener lesion occurs when the distal end of the completely torn UCL flips superficial to the adductor pollicis aponeurosis. This interposition prevents the ligament from healing to its anatomic footprint on the proximal phalanx, necessitating surgical repair.

Question 66

A 6-year-old boy presents with a Bado Type I Monteggia fracture-dislocation. Closed reduction of the apex-anterior ulnar diaphyseal fracture is achieved and pinned, but the radial head remains persistently dislocated anteriorly. What is the most common anatomical block to closed reduction of the radial head in this scenario?

Explanation

In Monteggia fracture-dislocations, if the radial head remains irreducible after restoring ulnar length and alignment, the most common block to reduction is soft tissue interposition, specifically the annular ligament or joint capsule.

Question 67

A 60-year-old female sustained a non-displaced distal radius fracture treated conservatively in a short arm cast. Six weeks later, she reports a sudden inability to actively extend the interphalangeal joint of her thumb. What is the primary pathophysiology behind this specific complication?

Explanation

Extensor pollicis longus (EPL) ruptures following non-displaced distal radius fractures are primarily ischemic in nature. The intact extensor retinaculum of the third dorsal compartment restricts swelling, leading to increased pressure, decreased synovial perfusion, and subsequent tendon necrosis and rupture.

Question 68

A 28-year-old male undergoes open reduction and internal fixation for a Galeazzi fracture (middle/distal third radial shaft fracture). Intraoperatively, after rigid plating of the radius, the distal radioulnar joint (DRUJ) is noted to be highly unstable in pronation and neutral, but reduces in supination. What is the most appropriate next step in management?

Explanation

In a Galeazzi fracture with persistent DRUJ instability after anatomic radius fixation, the joint should be reduced in its most stable position (usually supination) and secured with transverse radioulnar K-wires for 4-6 weeks to allow the TFCC to heal.

Question 69

A 45-year-old male presents with a mallet finger injury after a basketball struck his extended middle finger. Radiographs show a dorsal avulsion fracture of the distal phalanx involving 45% of the articular surface, accompanied by volar subluxation of the remaining distal phalanx. What is the recommended management?

Explanation

While most mallet fractures are treated non-operatively, surgical fixation (such as extension block pinning) is indicated for 'bony mallet' injuries involving greater than 30-40% of the articular surface or when there is volar subluxation of the distal phalanx.

Question 70

A 30-year-old male presents with severe forearm pain and pain with passive finger extension following a crush injury. Compartment pressures measure 45 mmHg, and an emergent volar fasciotomy is planned. Which muscle bellies in the forearm are most susceptible to ischemic necrosis and must be carefully decompressed due to their location in the deep volar compartment?

Explanation

The deep volar compartment contains the flexor digitorum profundus (FDP) and flexor pollicis longus (FPL). Because they rest directly against the interosseous membrane and bone, they are subjected to the highest pressures during compartment syndrome, making them the most susceptible to profound ischemia and subsequent Volkmann's ischemic contracture.

Radial Head Fractures: Symptoms, Diagnosis & Recovery

Comprehensive Orthopedic Review: Elbow & Hand Trauma, Fractures, Tendon Injuries | Part 22138

Key Takeaway

Comprehensive Orthopedic Review: Elbow & Hand Trauma, Fractures, Tendon Injuries | Part 22138

Chapter Index