This practice set contains high-yield board review questions covering key concepts in Elbow & Forearm. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
Question 841
Topic: Elbow & Forearm
Which statement best describes the 'line of sight' rule in assessing radial head alignment on radiographs?
Correct Answer & Explanation
. A line drawn through the center of the radial shaft should always pass through the capitellum in all radiographic views.
Explanation
The 'line of sight' or radiocapitellar line rule is a fundamental principle in assessing elbow radiographs for radial head dislocation. A line drawn through the center of the radial shaft, regardless of the degree of elbow flexion or forearm rotation, should always pass through the center of the capitellum. If this line does not intersect the capitellum, it confirms a radial head dislocation. This rule is crucial for identifying Monteggia fractures, as subtle radial head dislocations can be easily missed.
Question 842
Topic: Elbow & Forearm
What surgical consideration is paramount when performing open reduction and internal fixation of an adult Monteggia Type II fracture?
Correct Answer & Explanation
. Avoiding injury to the ulnar nerve due to its proximity to the posterior approach
Explanation
For a Monteggia Type II fracture, a posterior approach is often utilized to access the ulnar shaft fracture and facilitate posterior radial head reduction. During a posterior approach, the ulnar nerve is at risk, particularly as it passes through the cubital tunnel. Therefore, careful identification, protection, and potentially anterior transposition of the ulnar nerve are paramount surgical considerations to prevent iatrogenic injury. While minimizing incision length is good practice, it's not paramount in preventing HO (which is multifactorial). Radial head excision is not a primary step. The ulna fixation is still primary, and spontaneous reduction of the radial head is expected after stable ulnar fixation, but persistent dislocation requires open reduction of the radial head. Focusing on the radial head first is incorrect; the ulna is key.
Question 843
Topic: Elbow & Forearm
What is the most critical element to confirm on post-reduction radiographs for a Monteggia fracture?
Correct Answer & Explanation
. Concentric reduction of the radial head relative to the capitellum
Explanation
While proper ulnar alignment and overall forearm length are important, the most critical element to confirm on post-reduction radiographs for a Monteggia fracture is the concentric reduction of the radial head relative to the capitellum. A persistent radial head dislocation, even if the ulna is well-aligned, will lead to poor outcomes, pain, stiffness, and long-term instability. The 'line of sight' rule (a line through the radial shaft passing through the capitellum) must be satisfied on all views. The absence of a fat pad sign merely indicates resolution of swelling, and associated hand fractures are a separate concern.
Question 844
Topic: Elbow & Forearm
In a skeletally immature patient with an acute Monteggia Type I injury, which treatment modality is preferred if the radial head reduces concentrically with closed reduction and the ulnar fracture is stable?
Correct Answer & Explanation
. Long-arm cast immobilization with the elbow flexed and forearm supinated
Explanation
For acute Monteggia Type I injuries in skeletally immature patients (children), if a concentric reduction of the radial head can be achieved and maintained by closed means, and the ulnar fracture is stable (e.g., greenstick or plastic deformation), then long-arm cast immobilization is the preferred treatment. The elbow is typically flexed to 90 degrees and the forearm in full supination to stabilize the anteriorly dislocated radial head. Surgical fixation (ORIF) is reserved for unstable ulnar fractures or irreducible radial head dislocations. Radial head excision is contraindicated in children. Hinge braces are not appropriate for initial stabilization.
Question 845
Topic: Elbow & Forearm
What is a potential serious consequence of a chronic, unreduced radial head dislocation in a child following a Monteggia injury?
Correct Answer & Explanation
. Significant pain, decreased forearm rotation, and early degenerative changes in the radiocapitellar joint
Explanation
A chronic, unreduced radial head dislocation in a child following a Monteggia injury is a serious issue. It will not spontaneously reduce and will lead to significant long-term morbidity, including chronic pain, severely restricted forearm rotation (pronation/supination), and ultimately early degenerative changes (arthrosis) of the radiocapitellar joint due to abnormal joint mechanics. It can also lead to secondary deformity. Premature closure of the distal radial physis is not directly related. Valgus or varus deformities are less common primary sequelae than loss of rotation and degenerative changes.
Question 846
Topic: Elbow & Forearm
When is an annular ligament reconstruction typically indicated for a Monteggia fracture?
Correct Answer & Explanation
. When there is a chronic radial head dislocation with an attenuated or absent annular ligament after corrective ulnar osteotomy and radial head open reduction.
Explanation
Annular ligament reconstruction is generally indicated in cases of chronic, neglected Monteggia fractures, particularly in adults or older children, where the annular ligament is severely attenuated, scarred, or completely absent. After a corrective ulnar osteotomy and open reduction of the radial head, if the radial head remains unstable, reconstruction of the annular ligament (e.g., using a fascial graft) is often necessary to provide long-term stability. In acute settings, if the radial head reduces concentrically and is stable after ulnar fixation, reconstruction is typically not needed, as the native ligament (even if stretched) usually has healing potential.
Question 847
Topic: Elbow & Forearm
What anatomical feature of the radial head and capitellum joint makes its concentric reduction critical for long-term function?
Correct Answer & Explanation
. The congruency of the spherical capitellum articulating with the concave radial head, allowing for smooth rotation.
Explanation
The radiocapitellar joint is a critical articulation for forearm rotation. The spherical capitellum articulates with the concave radial head, forming a highly congruent joint that facilitates smooth pronation and supination. Any persistent incongruity or dislocation (as in an unreduced Monteggia fracture) disrupts this precise articulation, leading to abnormal loading, restricted rotation, pain, and accelerated degenerative changes. Concentric reduction is therefore paramount to restore normal biomechanics and preserve long-term function. Laxity and medial collateral ligaments are important but don't directly describe the primary articular function for rotation.
Question 848
Topic: Elbow & Forearm
What is the primary goal of surgical management for a chronic Monteggia fracture in a child with a persistently dislocated radial head?
Correct Answer & Explanation
. Corrective ulnar osteotomy with open reduction of the radial head and annular ligament reconstruction.
Explanation
For a chronic Monteggia fracture in a child with a persistently dislocated radial head, the primary goal of surgical management is to restore the normal anatomical relationship of the radiocapitellar joint. This typically involves a corrective ulnar osteotomy to restore forearm length and alignment, followed by open reduction of the radial head. Because the annular ligament is likely attenuated or absent in chronic cases, reconstruction of the annular ligament (e.g., with a fascial graft) is often necessary to stabilize the radial head. Radial head excision is generally avoided in children due to potential long-term issues like proximal radial migration and wrist pain. Arthrodesis or DRUJ fusion are salvage procedures and not primary treatment for chronic Monteggia. Dynamic splinting is adjunctive post-op, not primary treatment.
Question 849
Topic: Elbow & Forearm
Which of the following anatomical structures stabilizes the olecranon against varus stress?
Correct Answer & Explanation
. Lateral ulnar collateral ligament (LUCL)
Explanation
The Medial Collateral Ligament (MCL) (A), specifically its anterior bundle, is the primary static stabilizer of the elbow against valgus stress. While the question asks aboutvarusstress and the olecranon, the olecranon itself doesn't directly stabilize against varus stress in the same way the MCL resists valgus. However, the integrity of the ulnohumeral joint (where the olecranon articulates) is indirectly influenced by all ligamentous structures. The lateral ulnar collateral ligament (LUCL) (B) stabilizes against varus and posterolateral rotatory instability. Given the options and the 'stabilizes the olecranon' context, it's slightly ambiguous. Re-reading, it is asking what stabilizes 'the olecranon', which is part of the ulna, against varus stress. The LUCL stabilizes the ulnar side of the joint, preventing it from varus opening. Therefore, LUCL is the correct answer for varus stability related to the ulna/olecranon. My initial thought process was incorrect. The question isn't about the olecranon resisting varus stress, but what ligament prevents the ulna (and thus olecranon) from gapping open on the lateral side under varus stress. This would be the LUCL. Let me correct the answer and explanation.
Question 850
Topic: Elbow & Forearm
Which of the following anatomical structures primarily stabilizes the ulnohumeral joint against varus stress?
Correct Answer & Explanation
. Lateral ulnar collateral ligament (LUCL)
Explanation
The Lateral Ulnar Collateral Ligament (LUCL) (B) is the primary static stabilizer of the ulnohumeral joint (and thus the olecranon-bearing ulna) against varus stress and posterolateral rotatory instability. The Medial Collateral Ligament (MCL) (A) stabilizes against valgus stress. The annular ligament (C) stabilizes the radial head. The triceps tendon (D) extends the elbow. The interosseous membrane (E) connects the radius and ulna along the forearm.
Question 851
Topic: Elbow & Forearm
Which of the following is NOT an acceptable criterion for non-operative management of a diaphyseal forearm fracture in an adult?
Correct Answer & Explanation
. Radial head subluxation.
Explanation
Radial head subluxation (Option D) indicates a Monteggia equivalent injury, which is inherently unstable and typically requires operative management for both the ulna fracture and the radial head dislocation. The other options (A, B, C) represent commonly accepted parameters forsuccessfulnon-operative management of isolated diaphyseal forearm fractures in adults. An intact interosseous membrane (Option E) is not an 'acceptable criterion' per se, but rather a structural factor important for stability; a disrupted IM often indicates greater instability.
Question 852
Topic: Elbow & Forearm
A 6-year-old boy falls on an outstretched hand and presents with severe forearm pain. Radiographs demonstrate an isolated transverse fracture of the proximal ulnar diaphysis with apex-anterior angulation. The radiocapitellar line does not bisect the capitellum on any view. According to the Bado classification, what is the specific associated injury in this type of Monteggia fracture?
Correct Answer & Explanation
. Anterior dislocation of the radial head
Explanation
A Monteggia fracture-dislocation consists of a proximal third ulnar fracture with a radial head dislocation. The Bado classification describes the direction of the radial head dislocation, which generally follows the apex of the ulnar fracture angulation. Apex-anterior ulnar angulation is associated with an anterior dislocation of the radial head (Bado Type I), which is the most common type in children.
Question 853
Topic: Elbow & Forearm
A 45-year-old male sustains a fall onto an outstretched hand, resulting in severe elbow pain and deformity. Radiographs reveal a posterior elbow dislocation, a comminuted fracture of the coronoid process (O'Driscoll Type III), and a radial head fracture (Mason Type III). The elbow is grossly unstable after closed reduction. Which of the following is the most appropriate definitive surgical management strategy?
Correct Answer & Explanation
. Radial head arthroplasty, coronoid repair/reconstruction, and lateral collateral ligament repair.
Explanation
This patient presents with a 'terrible triad' injury of the elbow: posterior dislocation, radial head fracture, and coronoid fracture. This injury pattern is inherently unstable. The management principles involve addressing all components to restore stability and allow early motion. Mason Type III radial head fractures are comminuted and typically require radial head excision or arthroplasty. Coronoid fractures (especially O'Driscoll Type III, which involves the sublime tubercle or >50% of the coronoid) significantly destabilize the elbow and require fixation or reconstruction. Lateral collateral ligament (LCL) repair is crucial to restore posterolateral stability. Therefore, radial head arthroplasty (to replace the comminuted radial head), coronoid repair/reconstruction (to restore anterior stability), and LCL repair (to restore lateral stability) (Option C) represent the most appropriate and comprehensive surgical strategy. Simply excising the radial head and coronoid without reconstruction (Option B) would lead to persistent instability. ORIF of all fragments (Option A) is only feasible if fragments are large enough for fixation. A posterior olecranon osteotomy (Option D) is rarely needed for terrible triad injuries. Medial collateral ligament (MCL) repair (Option E) might be necessary if grossly unstable on valgus stress, but the LCL is the primary stabilizer injured in this pattern.
Question 854
Topic: Elbow & Forearm
A 45-year-old male bodybuilder sustains an acute distal biceps tendon rupture and opts for surgical repair via a single-incision anterior approach. Postoperatively, he complains of sensory loss along the lateral aspect of his forearm. Which nerve is most commonly injured during this specific surgical approach?
Correct Answer & Explanation
. Lateral antebrachial cutaneous nerve
Explanation
The lateral antebrachial cutaneous nerve (LABCN) is the most frequently injured nerve during a single-incision anterior approach to the distal biceps. It courses between the biceps and brachialis and exits laterally in the subcutaneous tissue, making it vulnerable during superficial dissection and retraction.
Question 855
Topic: Elbow & Forearm
A 35-year-old male falls on an outstretched hand and sustains a 'terrible triad' injury of the elbow. What is the standard algorithmic sequence for surgical fixation of this injury pattern?
The standard inside-out surgical algorithm for a terrible triad injury (coronoid fracture, radial head fracture, elbow dislocation) is: 1) Coronoid fixation or repair of the anterior capsule, 2) Radial head fixation or arthroplasty, 3) Lateral ulnar collateral ligament (LUCL) repair. Medial collateral ligament repair is only added if the elbow remains highly unstable after the first three steps.
Question 856
Topic: Elbow & Forearm
A 45-year-old man requires operative repair of a complete acute distal biceps tendon rupture. The surgeon must choose between a single-incision anterior approach and a two-incision approach. Compared to the single-incision technique, the two-incision approach has a historically higher risk of which of the following complications?
Correct Answer & Explanation
. Radioulnar synostosis
Explanation
The two-incision approach (modified Boyd-Anderson) was developed to limit radial nerve injury, but dissection between the radius and ulna significantly increases the risk of heterotopic ossification and radioulnar synostosis compared to a single anterior incision. The single-incision approach has a higher rate of lateral antebrachial cutaneous nerve (LABCN) neuropraxia due to anterior retraction.
Question 857
Topic: Elbow & Forearm
A 30-year-old patient presents with a 'terrible triad' injury of the elbow following a fall onto an outstretched hand. The injury involves an elbow dislocation, a radial head fracture, and a coronoid process fracture. According to standard surgical protocols, what is the most widely accepted sequence of structural repair to restore elbow stability?
The standard inside-out surgical sequence for a terrible triad injury of the elbow is: 1. Fixation of the coronoid fracture (or reattachment of the anterior capsule), 2. Fixation or replacement of the radial head, 3. Repair of the lateral collateral ligament (LUCL) to the lateral epicondyle. The medial collateral ligament (MCL) is only repaired or a hinged external fixator applied if the elbow remains unstable in extension after the lateral side is secured.
Question 858
Topic: Elbow & Forearm
A 34-year-old female sustains a coronal shear fracture of the distal humerus. Imaging demonstrates that the fracture involves both the capitellum and the lateral half of the trochlea in a single contiguous articular fragment. According to the Dubberley classification, this represents a Type 3 injury. What specific radiographic feature differentiates a Dubberley Type 3B from a Type 3A injury?
Correct Answer & Explanation
. Presence of posterior condylar comminution
Explanation
The Dubberley classification of coronal shear fractures divides them by extent: Type 1 involves the capitellum only, Type 2 includes the capitellum and the lateral trochlear ridge, and Type 3 involves the capitellum and trochlea as a single piece. The modifier A or B is added based on the absence (A) or presence (B) of posterior condylar comminution, which is critical because Type B injuries lack posterior cortical buttressing and often require specialized plating.
Question 859
Topic: Elbow & Forearm
A 28-year-old male describes a sensation of his elbow 'clicking and giving way' when he tries to push himself up from an armchair. Physical exam reveals apprehension and a clunk with a supination, valgus, and axial compression load applied to the elbow as it is moved from extension to flexion. What is the primary ligamentous restraint that is deficient, and what is its anatomic insertion on the ulna?
Correct Answer & Explanation
. Lateral ulnar collateral ligament; supinator crest of the ulna
Explanation
The patient is presenting with Posterolateral Rotatory Instability (PLRI) of the elbow. The primary deficient structure is the Lateral Ulnar Collateral Ligament (LUCL). The LUCL originates from the lateral epicondyle, blends with the annular ligament, and inserts on the supinator crest of the proximal ulna. Its incompetence allows the radial head and proximal ulna to subluxate posterolaterally away from the humerus.
Question 860
Topic: Elbow & Forearm
A 45-year-old female falls on her outstretched hand. Radiographs confirm an elbow dislocation, a comminuted radial head fracture, and a Type II coronoid fracture.
According to standard surgical protocols for this 'terrible triad' injury, what is the most appropriate sequence of repair to restore elbow stability?
Correct Answer & Explanation
. Coronoid fixation/capsular repair, radial head fixation/replacement, LUCL repair
Explanation
The classic 'terrible triad' of the elbow includes an elbow dislocation, radial head fracture, and coronoid fracture. The widely accepted surgical protocol described by Pugh and McKee recommends repairing structures from deep to superficial, typically starting anteriorly: 1) Coronoid fixation or anterior capsule repair to restore the anterior buttress, 2) Radial head ORIF or arthroplasty, 3) LUCL repair to the lateral epicondyle, and 4) MCL repair or application of a hinged external fixator if the elbow remains unstable after the first three steps.
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