This practice set contains high-yield board review questions covering key concepts in 2. Trauma. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
Question 1281
Topic: 2. Trauma
A surgeon uses a submuscular bridge plating technique with a locking plate for a highly comminuted tibial shaft fracture. What is the recommended screw density (ratio of occupied holes to total plate holes) to balance fixation stability while preventing excessive construct stiffness?
Correct Answer & Explanation
. 0.4 to 0.5
Explanation
In bridge plating techniques, a screw density of 0.4 to 0.5 is recommended. This avoids creating an overly stiff construct, ensuring there is enough strain at the fracture gap to stimulate callus formation while maintaining adequate mechanical stability.
Question 1282
Topic: 2. Trauma
Following initial reduction of the elbow dislocation in a terrible triad injury, a surgeon notes persistent instability, particularly with varus stress and supination. A preoperative CT scan was obtained, revealing a comminuted radial head fracture and a Type II coronoid fracture (Regan-Morrey classification). Based on the case description and standard management principles, what is the most appropriate next step in surgical management to address the persistent instability?
Correct Answer & Explanation
. C. Excision of the radial head fragments, followed by coronoid fixation and radial head replacement.
Explanation
Correct Answer: CThe case describes a terrible triad with persistent instability after reduction. The operative sequence outlined in the teaching case emphasizes restoring ulnohumeral joint stability. The first step after addressing the lateral structures (which are often torn) and gaining access is to excise the radial head fragments. This provides access to the coronoid and anterior capsule. Subsequently, the coronoid fracture is addressed (fixation or capsule repair), followed by radial head replacement. This sequence systematically rebuilds the elbow's stability. A Type II coronoid fracture (involving 50% or less of the coronoid height) is typically amenable to direct fixation.Option A (Immediate application of a hinged external fixator without further internal fixation)is incorrect. While an external fixator may be used as an augmentation if instability persists after internal fixation, it is not the primary treatment for the bony and ligamentous injuries in a terrible triad. Internal fixation of the coronoid and radial head replacement are crucial for restoring stability.Option B (Repair of the medial collateral ligament (MCL) as the primary stabilizer)is incorrect. While the MCL may be injured, the primary instability in a terrible triad is often posterolateral rotatory instability due to LCL disruption. The teaching case states that MCL repair is considered if residual instability persistsfollowing fixationof the other structures, not as the initial primary stabilizer repair.Option D (Primary repair of the anterior capsule to the coronoid footprint)is incorrect as the primary next step. While this is an option for coronoid management, it is typically performed if the coronoid fragment is too small to fix directly. For a Type II coronoid fracture, direct fixation is generally preferred if feasible, as described in the teaching case (fix with a single screw or suture the anterior capsule down to the coronoid footprint using suture anchors, depending on fragment size).Option E (Debridement of the olecranon fossa to prevent impingement)is incorrect. This is not a standard or primary step in the management of acute terrible triad injuries and does not address the fundamental instability.
Question 1283
Topic: 2. Trauma
A 55-year-old female presents with a terrible triad injury. During the preoperative planning phase, the surgeon emphasizes the importance of a CT scan. What specific information, beyond what plain radiographs provide, is most crucial for guiding the operative approach and fixation strategy in this case?
Correct Answer & Explanation
. B. Detailed evaluation of the degree of comminution and displacement of the coronoid and radial head fractures.
Explanation
Correct Answer: BThe teaching case states: 'A preoperative CT scan would provide useful information regarding the degree of comminution, fracture fragment origin, degree of displacement, and other factors to be considered during the operation.' While plain radiographs confirm the dislocation and presence of fractures, a CT scan offers detailed 3D information about the fracture patterns, fragment size, and displacement of both the radial head and coronoid. This detail is critical for deciding between radial head fixation vs. replacement, and coronoid fixation vs. anterior capsule repair, as well as planning the specific approach and hardware.Option A (Assessment of the integrity of the distal radioulnar joint (DRUJ))is incorrect. While DRUJ integrity is important in forearm trauma, it is not the primary focus for a terrible triad of the elbow. A terrible triad involves the proximal forearm and elbow joint, not typically the wrist.Option C (Confirmation of the presence of an elbow dislocation)is incorrect. Plain radiographs are usually sufficient to confirm an elbow dislocation. A CT scan provides more detail on the bony injuries, not just the presence of dislocation.Option D (Identification of potential neurovascular compromise)is incorrect. Neurovascular compromise is primarily assessed clinically (pulses, sensation, motor function) and can be further evaluated with angiography or nerve conduction studies if indicated, but not typically the primary role of a routine preoperative CT for fracture detail.Option E (Measurement of the carrying angle of the elbow)is incorrect. The carrying angle is a static anatomical measurement and is not a primary concern for acute fracture management or operative planning in a terrible triad.
Question 1284
Topic: Upper Extremity Trauma
A 40-year-old patient undergoes surgical repair of a terrible triad injury. Postoperatively, the patient develops significant elbow stiffness, limiting both flexion/extension and pronation/supination. Which of the following factors is most commonly associated with the development of postoperative elbow stiffness after a terrible triad injury repair?
Correct Answer & Explanation
. B. Prolonged immobilization of the elbow joint.
Explanation
Correct Answer: BProlonged immobilization of the elbow joint is a well-known risk factor for postoperative stiffness after any elbow trauma or surgery, including terrible triads. While some period of immobilization is necessary for soft tissue and bone healing, excessive or prolonged immobilization can lead to capsular contracture, adhesions, and heterotopic ossification, all contributing to stiffness. The goal of terrible triad repair is to achieve stability sufficient for early, controlled range of motion.Option A (Early, aggressive passive range of motion exercises)is incorrect. While overly aggressive or uncontrolled motion can sometimes lead to complications, early, controlled range of motion is generally encouraged to prevent stiffness, not cause it, once stability is achieved.Option C (Inadequate repair of the medial collateral ligament)is incorrect. Inadequate MCL repair would primarily lead to valgus instability, not necessarily stiffness. While instability can indirectly lead to guarding and stiffness, it's not the most direct cause of stiffness compared to immobilization.Option D (Overstuffing of the radial head prosthesis)is correct in that it can cause stiffness and pain, but the question asks for the 'most commonly associated' factor. While overstuffing is a significant cause of stiffness and pain, prolonged immobilization is a more pervasive and common cause of stiffness across various elbow injuries and surgeries.Option E (Failure to decompress the ulnar nerve during surgery)is incorrect. Failure to decompress the ulnar nerve would primarily lead to ulnar neuropathy symptoms (pain, numbness, weakness), not directly to global elbow stiffness.
Question 1285
Topic: Upper Extremity Trauma
A 60-year-old patient with a terrible triad injury undergoes successful surgical repair. During the immediate postoperative period, the patient is placed in a hinged elbow brace. What is the primary biomechanical rationale for using a hinged elbow brace in the early rehabilitation phase following a terrible triad repair?
Correct Answer & Explanation
. C. To allow controlled range of motion while protecting the repaired ligaments from excessive stress.
Explanation
Correct Answer: CThe primary rationale for a hinged elbow brace is to allow controlled range of motion (flexion and extension) within a safe arc, while simultaneously protecting the repaired ligaments (especially the LCL and potentially MCL) from excessive varus, valgus, or rotatory stresses. This balance promotes healing, prevents stiffness, and maintains joint congruity.Option A (To completely immobilize the elbow joint to allow for maximal soft tissue healing)is incorrect. A hinged brace allows motion, it does not completely immobilize. Complete immobilization is generally avoided in terrible triads due to the high risk of stiffness.Option B (To prevent heterotopic ossification by limiting joint motion)is incorrect. While limiting motion can sometimes be part of a strategy to prevent HO, the primary mechanism for a hinged brace is controlled motion, not strict limitation for HO prevention. Early motion is often thought to help prevent HO.Option D (To provide continuous passive motion (CPM) without patient effort)is incorrect. A hinged brace allows active or passive motion within its set limits, but it does not provide CPM automatically. CPM machines are separate devices.Option E (To reduce swelling and inflammation around the elbow joint)is incorrect. While a brace might offer some compression, its primary role is mechanical protection and controlled motion, not direct management of swelling or inflammation.
Question 1286
Topic: 2. Trauma
A 45-year-old male presents to the emergency department after a fall onto an outstretched hand. Radiographs of his elbow are shown below. He has sustained a fracture of the proximal ulna with anterior angulation and an anterior dislocation of the radial head. Based on these findings, which Bado classification type does this injury most accurately describe?
Correct Answer & Explanation
. Type I
Explanation
The Bado classification defines Monteggia fractures based on the direction of radial head dislocation and the location/angulation of the ulnar fracture. Type I involves an anterior dislocation of the radial head with an associated anteriorly angulated ulnar shaft fracture. This is the most common variant, accounting for approximately 60% of all Monteggia injuries. The image clearly depicts these features. Type II involves posterior dislocation of the radial head. Type III involves lateral/anterolateral dislocation with a metaphyseal ulnar fracture. Type IV involves both radial and ulnar shaft fractures with anterior radial head dislocation. Galeazzi fractures involve a distal radial shaft fracture with associated distal radioulnar joint disruption, which is a different injury pattern.
Question 1287
Topic: 2. Trauma
A 7-year-old child presents with elbow pain and swelling after falling from a tree. Radiographs, as shown below, reveal a subtle greenstick fracture of the ulnar metaphysis and a lateral dislocation of the radial head. Which Bado classification type is this injury?
Correct Answer & Explanation
. Type III
Explanation
This presentation describes a Bado Type III Monteggia fracture. Type III is characterized by a fracture of the ulnar metaphysis (often proximally, near the olecranon or coronoid, and frequently a greenstick or plastic deformation in children) with an associated lateral or anterolateral dislocation of the radial head. This type is more common in children due to the inherent elasticity of pediatric bones and ligaments, and it is often subtle, making it prone to being missed. Type I is anterior radial head dislocation with an anteriorly angulated ulnar shaft fracture; Type II is posterior radial head dislocation with a posteriorly angulated ulnar shaft fracture; Type IV is anterior radial head dislocation with fractures of both the ulna and radius shafts. Essex-Lopresti is a radial head fracture with interosseous membrane disruption and DRUJ dissociation, which is a different injury.
Question 1288
Topic: 2. Trauma
A 30-year-old male sustains a Monteggia Type I fracture, as depicted in the pre-operative image. What is the generally accepted definitive treatment for an adult with this injury?
Correct Answer & Explanation
. Open reduction and internal fixation (ORIF) of the ulnar fracture, which often reduces the radial head spontaneously
Explanation
Correct Answer: BFor adult Monteggia fractures (of all types, but particularly Type I), the definitive treatment is almost universally open reduction and internal fixation (ORIF) of the ulnar fracture. Achieving stable anatomical reduction and fixation of the ulna is critical. In the vast majority of cases, once the ulna is anatomically reduced and stably fixed, the radial head will spontaneously reduce due to the intact interosseous membrane and annular ligament. Closed reduction is rarely successful or stable in adults due to higher forces and less robust periosteum. Excision of the radial head is not indicated for acute Monteggia fractures. External fixation might be considered in highly contaminated open fractures, but ORIF remains the standard. Radial head arthroplasty is indicated for severe comminuted radial head fractures, not primary Monteggia treatment where the radial head is typically intact.
Question 1289
Topic: 2. Trauma
Following successful ORIF of a Monteggia Type I fracture in an adult, as shown in the post-operative image, the patient develops a posterior interosseous nerve (PIN) palsy. Which of the following is the most appropriate initial management step?
Correct Answer & Explanation
. Observation and physiotherapy, as PIN palsies are often neurapraxic and resolve spontaneously
Explanation
Correct Answer: BPosterior interosseous nerve (PIN) palsy is a known, albeit uncommon, complication of Monteggia fractures or their treatment. The PIN is vulnerable as it courses through the supinator muscle. Most PIN palsies associated with Monteggia injuries are neurapraxias or axonotmesis due to traction or compression, and a significant proportion resolve spontaneously over several weeks to months. Therefore, the initial management is typically observation, protection, and physiotherapy to prevent contractures, monitoring for recovery. Surgical exploration is generally reserved for cases that show no signs of recovery after 3-6 months. High-dose corticosteroids are not proven effective. EMG/NCS studies are usually performed after 3-4 weeks to establish a baseline or later if recovery is not observed. Immobilization in extension is not indicated and could cause stiffness.
Question 1290
Topic: 2. Trauma
A 55-year-old patient presents with chronic elbow pain, limited pronation/supination, and a palpable radial head dislocation that was missed 6 months ago following a fall. Radiographs, as shown, confirm a Monteggia Type I malunion with chronic anterior radial head dislocation. Which of the following is the most appropriate management option?
Correct Answer & Explanation
. Corrective osteotomy of the ulna with open reduction of the radial head and annular ligament reconstruction
Explanation
Correct Answer: BA missed or chronic Monteggia fracture in an adult typically requires surgical intervention. For a chronic Monteggia Type I malunion, a staged approach often involves a corrective osteotomy of the malunited ulna to restore forearm length and rotation, followed by open reduction of the radial head. If the annular ligament is significantly disrupted or non-functional, reconstruction (e.g., using a strip of triceps fascia, forearm fascia, or allograft) is often necessary to stabilize the reduced radial head. Closed reduction is ineffective for chronic dislocations. Radial head excision alone in the presence of an intact ulna can lead to superior migration of the radius (Essex-Lopresti type sequela) and wrist pain due to disruption of forearm stability. Dynamic splinting may be used post-operatively but is not the primary treatment. Elbow arthrodesis is a salvage procedure for severe pain and instability, not initial management for a chronic Monteggia.
Question 1291
Topic: 2. Trauma
A patient presents with a Monteggia fracture. During clinical assessment, the ability to extend the fingers at the MCP joints and the thumb is tested. Which nerve is most commonly injured in Monteggia fractures, particularly Type I, leading to deficits in these movements?
Correct Answer & Explanation
. Posterior interosseous nerve (PIN)
Explanation
Correct Answer: DThe posterior interosseous nerve (PIN), a deep motor branch of the radial nerve, is the most commonly injured nerve in Monteggia fractures. It is particularly vulnerable in Type I fractures due to the anterior displacement of the radial head and the hyperpronation mechanism, causing significant stretching as the nerve passes through the supinator muscle (arcade of Frohse). PIN palsy manifests as weakness or inability to extend the fingers at the MCP joints and weakness of thumb extension (extensor pollicis longus and brevis). Most PIN palsies associated with Monteggia injuries are neurapraxic and recover spontaneously, but careful monitoring is essential. While the radial nerve proper, median, and ulnar nerves can be injured in elbow trauma, the PIN has a specific vulnerability in Monteggia injuries.
Question 1292
Topic: 2. Trauma
A 12-year-old patient presents with an ulnar shaft fracture and an associated radial head fracture, along with radial head dislocation, as shown in the image. This injury pattern is considered a Monteggia equivalent lesion. What is a characteristic feature differentiating a Monteggia equivalent lesion from a classic Monteggia fracture?
Correct Answer & Explanation
. Presence of a radial head fracture in addition to the ulnar fracture and radial head dislocation
Explanation
Correct Answer: BMonteggia equivalent lesions are a group of injuries that are biomechanically similar to Monteggia fractures (ulnar injury + radial head dislocation) but include additional or slightly different injury patterns. A common Monteggia equivalent, as described in the vignette and depicted in the image, is a Monteggia fracture with an associated fracture of the radial head (or neck) in addition to the ulnar fracture and radial head dislocation. Other equivalents include ulnar diaphyseal fracture with concomitant ipsilateral distal radial fracture, or proximal ulna physeal fracture with radial head dislocation. They are not limited to pediatric patients, and the annular ligament is almost always involved (torn or stretched). They do involve an ulnar injury, even if not always a diaphyseal fracture (e.g., physeal). Wrist joint involvement is typical for Essex-Lopresti, not standard Monteggia equivalents.
Question 1293
Topic: 2. Trauma
A 30-year-old male sustains a proximal third ulnar shaft fracture with an associated anterior dislocation of the radial head. According to the Bado classification, what type of Monteggia lesion is this?
Correct Answer & Explanation
. Type I
Explanation
Bado Type I is characterized by an anterior dislocation of the radial head with a fracture of the ulnar diaphysis at any level, typically anteriorly angulated. It is the most common type in pediatric patients but can also occur in adults.
Question 1294
Topic: 2. Trauma
A 25-year-old male presents with a Bado Type II Monteggia fracture-dislocation. Which of the following injury patterns is most frequently associated with this specific Bado classification in adults?
Correct Answer & Explanation
. Radial head fracture
Explanation
Bado Type II Monteggia injuries involve a posterior or posterolateral radial head dislocation with a posteriorly angulated ulnar fracture. They are most common in adults and have a high association with ipsilateral radial head fractures.
Question 1295
Topic: Upper Extremity Trauma
A 42-year-old male underwent ORIF of a terrible triad injury 6 months ago. He now lacks 45 degrees of extension and is limited to 100 degrees of flexion. Radiographs show mature heterotopic ossification (HO) bridging the lateral collateral ligament complex. What is the best management strategy?
Correct Answer & Explanation
. Perform surgical excision of the mature HO and consider prophylaxis
Explanation
Heterotopic ossification is a recognized complication after terrible triad injuries. Surgical excision is indicated to restore motion once the HO is fully mature (indicated by sharp radiographic borders and normal inflammatory markers, typically 6-12 months post-injury), usually combined with radiation or indomethacin prophylaxis.
Question 1296
Topic: 2. Trauma
A patient with a missed Bado Type I Monteggia fracture presents 6 months post-injury. The ulna has healed with significant apex-anterior angulation, and the radial head remains anteriorly dislocated. What is the most critical step in the surgical reconstruction of this chronic injury?
Correct Answer & Explanation
. Ulnar osteotomy to restore length and correct angulation
Explanation
The fundamental principle in treating chronic Monteggia fractures is restoring the anatomical length and alignment of the ulna via a corrective osteotomy. Without correcting the ulnar deformity, the radial head cannot be successfully reduced or maintained in position.
Question 1297
Topic: Upper Extremity Trauma
In a patient presenting with a terrible triad of the elbow, which of the following physical exam findings is most indicative of an associated Essex-Lopresti injury?
Correct Answer & Explanation
. Distal radioulnar joint (DRUJ) instability and wrist pain
Explanation
An Essex-Lopresti lesion involves a radial head fracture, rupture of the interosseous membrane, and DRUJ disruption. Concomitant wrist pain and DRUJ instability in the setting of a terrible triad strongly suggest this injury, strictly contraindicating radial head excision.
Question 1298
Topic: 2. Trauma
Which of the following neurologic deficits is most classically associated with a Bado type II Monteggia fracture-dislocation in an adult patient?
Correct Answer & Explanation
. Inability to actively extend the thumb interphalangeal joint
Explanation
Posterior interosseous nerve (PIN) palsy is the most common neurologic injury in Monteggia fractures, particularly Bado type II and III. It presents with an inability to extend the fingers at the MCP joints and the thumb at the IP joint, without sensory loss.
Question 1299
Topic: 2. Trauma
In the context of a terrible triad elbow injury, what fracture pattern of the coronoid process is most frequently encountered and targeted for repair to restore the anterior soft-tissue buttress?
Correct Answer & Explanation
. A transverse fracture of the coronoid tip
Explanation
Terrible triad injuries typically involve a transverse fracture of the coronoid tip (Regan-Morrey Type I or II). Repairing this fragment or using a suture lasso technique effectively reattaches the anterior capsule, restoring the critical anterior buttress to prevent posterior subluxation.
Question 1300
Topic: 2. Trauma
Following appropriate surgical reconstruction of a terrible triad injury, the patient returns for routine follow-up at 6 months postoperatively. Despite compliance with therapy, what is the most common complication this patient is likely to experience?
Correct Answer & Explanation
. Elbow stiffness
Explanation
Elbow stiffness (loss of terminal extension and/or flexion) is the most common complication following the surgical treatment of a terrible triad injury. Early, supervised active range of motion is critical to minimize this complication.
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