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 381
Topic: Elbow & Forearm
A 15-year-old female gymnast is diagnosed with a capitellar osteochondritis dissecans (OCD) lesion. MRI shows the articular cartilage is intact. Which radiographic view best profiles the capitellum to monitor lesion size and healing during non-operative management?
Correct Answer & Explanation
. Standard AP view
Explanation
The capitellum is situated anteriorly on the distal humerus. The AP axial view (taken with the elbow flexed 45 degrees) best profiles the articular surface of the capitellum, clearly demonstrating OCD lesions.
Question 382
Topic: Elbow & Forearm
A 10-year-old girl has a right elbow deformity that is the result of trauma 5 years ago. She has no pain despite the arm deformity. The radiographs in Figures 42a and 42b show complete healing. This radiographic appearance demonstrates what complication?
Correct Answer & Explanation
. Varus malunion of a supracondylar humeral fracture
Explanation
Cubitus varus is a common complication of displaced supracondylar humeral fractures that are treated with closed reduction and cast immobilization. Treatment with closed reduction and percutaneous pinning decreases the incidence of this complication. Cubitus varus also can occur in minimally displaced fractures when unrecognized collapse of the medial column of the distal humerus is not corrected with manipulation. This can be detected on physical examination of the carrying angle or on radiographs measuring Baumann’s angle, both in comparison to the opposite side. Cubitus varus may result in unacceptable cosmesis and may predispose the patient to fractures of the lateral condyle. The lateral radiograph demonstrates the crescent sign from overlap of the distal humerus with the olecranon seen in patients with cubitus varus.
Question 383
Topic: Elbow & Forearm
A 51-year-old female sustained a comminuted radial head fracture with 4 fragments and an associated elbow dislocation. She was initially closed reduced and splinted with the elbow joint in a reduced position and presents to the orthopedist's office 10 days later. In response to the patient's question of what treatment offers the best chance for a good outcome, the surgeon should recommend?
Correct Answer & Explanation
. Radial head arthroplasty
Explanation
In a classic article, Ring et al reported that ORIF of radial head fractures with more than 3 fragments has poor results and recommend radial head replacement for these fractures. Metallic implants are the material of choice for radial head replacement. Silicone implants were often used in the past and have many well-documented complications including prosthesis failure, adverse tissue reaction, and poor load transfer. Excision is not appropriate in the setting of a radial head fracture associated with elbow instability.
Question 384
Topic: Elbow & Forearm
A 22-year-old elite basketball player undergoes open surgical debridement of the inferior pole of the patella for chronic, refractory 'jumper’s knee' (patellar tendinopathy). Which of the following describes the most likely classic histologic findings in the excised pathologic tendon tissue?
Correct Answer & Explanation
. Disorganized collagen, mucoid ground substance, and angiofibroblastic hyperplasia without acute inflammatory cells
Explanation
Chronic patellar tendinopathy (jumper's knee), like lateral epicondylitis and Achilles tendinopathy, is histologically a 'tendinosis' rather than a true 'tendinitis'. Pathologic evaluation of the diseased tendon demonstrates a lack of active acute inflammatory cells. Instead, the tissue exhibits angiofibroblastic hyperplasia, mucoid (myxoid) degeneration, disorganized collagen architecture (increased Type III collagen relative to Type I), and increased cellularity of poorly differentiated fibroblasts. This process represents a failed healing response rather than an active inflammatory cascade.
Question 385
Topic: Elbow & Forearm
A 62-year-old man slips on ice and sustains an elbow dislocation. Post-reduction imaging reveals a highly comminuted radial head fracture and coronoid fracture through its base. What is the most appropriate treatment?
Correct Answer & Explanation
. Radial head replacement, open reduction internal fixation of the coronoid, and repair of the lateral ulnar collateral ligament and medial collateral as needed
Explanation
DISCUSSION: The results of elbow dislocations with associated radial head and coronoid fractures are often poor because of recurrent instability and/or stiffness from prolonged immobilization. Therefore, radial head replacement and open reduction internal fixation of the coronoid is the most appropriate treatment. Pugh et al reported their experiences with this difficult population. Their protocol consisted of ORIF or replacement of the radial head, ORIF of the coronoid fracture, repair of the LCL and capsule, and repair of the MCL and/or hinged external fixation. Of the 36 cases, the outcome was graded as 28 excellent to good, 7 fair, and 1 poor. 8 cases required re-operation. The authors concluded that their surgical protocol restored sufficient elbow stability to allow early motion post-op, thereby enhancing the functional outcome. In fracture dislocation of the elbow with radial head and coronoid fracture, the radial head must be fixed or replaced to restore stability. The ORIF of coronoid fracture and radial head restores some valgus stability, therefore MCL repair may not be needed. However, the varus stability must be restored by LCL repair.
Question 386
Topic: Elbow & Forearm
A 35-year-old male suffers a distal biceps tendon rupture and undergoes surgical repair via a two-incision technique. Compared to the single anterior incision technique, the two-incision approach is associated with a higher risk of which of the following complications?
Correct Answer & Explanation
. Radioulnar synostosis
Explanation
The two-incision technique for distal biceps repair was developed to avoid the radial nerve (PIN) injuries sometimes seen with the single-incision approach. However, the two-incision technique carries a significantly higher risk of heterotopic ossification and radioulnar synostosis due to muscle splitting and subperiosteal dissection near the ulna. Conversely, the single anterior incision approach has a higher risk of lateral antebrachial cutaneous nerve (LABCN) neurapraxia.
Question 387
Topic: Elbow & Forearm
A 6-year-old boy presents to the emergency department after falling from monkey bars. Radiographs reveal a plastic deformation of the ulnar shaft and an anterior dislocation of the radial head. This corresponds to a Bado Type I Monteggia equivalent lesion.
What is the most appropriate initial management for this injury?
Correct Answer & Explanation
. Closed reduction of the ulnar deformity, which typically reduces the radial head, followed by casting
Explanation
A Monteggia fracture-dislocation in a pediatric patient (including equivalent lesions with ulnar plastic deformation) is fundamentally an injury driven by the ulnar deformity. The appropriate initial management is closed reduction to correct the ulnar bowing/angulation. Once the anatomic length and alignment of the ulna are restored, the radial head almost always reduces spontaneously into its anatomic position. Immobilization in a long arm cast (usually in supination for anterior/Type I lesions) is then performed. Open reduction or ulnar osteotomy is reserved for cases where closed reduction fails to restore ulnar alignment or reduce the radial head.
Question 388
Topic: Elbow & Forearm
A 35-year-old male complains of a painful "clunk" and giving way of his right elbow when he pushes himself out of a chair with his arms. A lateral pivot-shift test of the elbow reproduces his symptoms. This condition is primarily caused by insufficiency of a specific ligamentous structure. What is the normal anatomic origin and insertion of the deficient ligament?
Correct Answer & Explanation
. Originates on the lateral epicondyle; inserts onto the supinator crest of the ulna
Explanation
The patient is presenting with posterolateral rotatory instability (PLRI) of the elbow. PLRI is caused by insufficiency of the Lateral Ulnar Collateral Ligament (LUCL). The LUCL originates on the lateral epicondyle of the humerus, blends with the fibers of the annular ligament, and inserts onto the supinator crest of the proximal ulna. It acts as the primary restraint to posterolateral rotatory subluxation of the radial head relative to the capitellum.
Question 389
Topic: Elbow & Forearm
A 40-year-old woman falls on an outstretched hand and sustains a 'terrible triad' injury of the elbow.
Which of the following describes the most universally accepted sequence of intraoperative repair for this injury?
Correct Answer & Explanation
. Coronoid fixation, radial head fixation/replacement, LCL repair
Explanation
The standard surgical algorithm for a terrible triad injury (elbow dislocation, radial head fracture, coronoid fracture) typically proceeds from deep to superficial: 1. Fixation of the coronoid fracture (or anterior capsule repair). 2. Fixation or replacement of the radial head. 3. Repair of the lateral collateral ligament (LCL) complex to the lateral epicondyle. If the elbow remains unstable after these steps, the medial collateral ligament (MCL) may be repaired or an external fixator applied.
Question 390
Topic: Elbow & Forearm
A 42-year-old woman falls on her outstretched hand and sustains a shear fracture of the distal humerus articular surface. Radiographs reveal a fracture involving the capitellum and the lateral half of the trochlea, with a large piece of subchondral bone attached. According to the Bryan and Morrey classification, what type of fracture is this?
Correct Answer & Explanation
. Type IV (McKee)
Explanation
The Bryan and Morrey classification describes capitellum fractures. Type I (Hahn-Steinthal): involves a large fragment of osseous capitellum. Type II (Kocher-Lorenz): an articular cartilage fracture with very little subchondral bone attached. Type III (Broberg-Morrey): severely comminuted capitellum fracture. Type IV (added by McKee): involves the capitellum and the lateral half of the trochlea. The presence of the trochlear extension is critical to recognize as it requires more extensive fixation.
Question 391
Topic: Elbow & Forearm
A 38-year-old male undergoes surgical repair of a complete distal biceps tendon rupture using a single-incision anterior approach. Postoperatively, he complains of numbness over the radial aspect of his volar forearm. Which structure was most likely injured during the procedure?
Correct Answer & Explanation
. Lateral antebrachial cutaneous nerve
Explanation
The lateral antebrachial cutaneous nerve (LABCN) runs closely alongside the cephalic vein and biceps tendon distally. It is the most commonly injured neurologic structure during a single-incision anterior approach for distal biceps repair.
Question 392
Topic: Elbow & Forearm
A 28-year-old female complains of recurrent clicking and a sense of instability in her elbow when pushing up from a chair. Physical examination reveals apprehension during a pivot-shift test. This condition is primarily due to insufficiency of which of the following structures?
Correct Answer & Explanation
. Lateral ulnar collateral ligament (LUCL)
Explanation
Posterolateral rotatory instability (PLRI) of the elbow presents with a positive lateral pivot-shift test and apprehension when extending the elbow with supination and an axial load. It is primarily caused by an incompetent lateral ulnar collateral ligament (LUCL).
Question 393
Topic: Elbow & Forearm
A 45-year-old male falls from a height and sustains a comminuted radial head fracture, along with significant wrist pain. Radiographs show proximal migration of the radius. If the radial head is resected without replacement in this setting, what is the most likely biomechanical consequence?
Correct Answer & Explanation
. Distal radioulnar joint (DRUJ) instability and ulnocarpal impaction
Explanation
This presentation describes an Essex-Lopresti injury (radial head fracture, interosseous membrane tear, DRUJ disruption). Resecting the radial head without replacement eliminates the proximal block to migration, resulting in severe proximal radial migration and secondary ulnocarpal impaction.
Question 394
Topic: Elbow & Forearm
Following an unsalvageable radial head fracture, a metallic radial head arthroplasty is planned. To prevent overstuffing the radiocapitellar joint, the proximal articular surface of the radial head implant should ideally be placed at which anatomic landmark relative to the proximal radioulnar joint (PRUJ)?
Correct Answer & Explanation
. Flush with or slightly proximal (within 1-2 mm) to the lateral edge of the lesser sigmoid notch
Explanation
To restore proper elbow kinematics and avoid overstuffing, the proximal rim of the radial head implant should be placed flush with, or no more than 1-2 mm proximal to, the lateral edge of the lesser sigmoid notch of the ulna.
Question 395
Topic: Elbow & Forearm
A 32-year-old female sustains a coronal shear fracture of the distal humerus that involves the capitellum and the lateral half of the trochlea. Which classification accurately describes this fracture pattern?
Correct Answer & Explanation
. McKee modification of Bryan-Morrey Type IV
Explanation
The McKee modification of the Bryan-Morrey classification describes a Type IV fracture as a coronal shear fracture that involves the capitellum and extends medially to include the lateral portion of the trochlea. This creates a pathognomonic 'double-arc' sign on a lateral radiograph.
Question 396
Topic: Elbow & Forearm
Which tendon is most commonly and primarily involved in the underlying pathoanatomy of lateral epicondylitis (tennis elbow)?
Correct Answer & Explanation
. Extensor carpi radialis brevis
Explanation
Lateral epicondylitis is characterized by angiofibroblastic hyperplasia primarily occurring at the origin of the extensor carpi radialis brevis (ECRB) tendon.
Question 397
Topic: Elbow & Forearm
A 42-year-old male sustains an Essex-Lopresti injury characterized by a comminuted radial head fracture, rupture of the interosseous membrane, and disruption of the distal radioulnar joint (DRUJ). In the acute setting, what is the most appropriate management of the radial head?
Correct Answer & Explanation
. Radial head arthroplasty
Explanation
In an Essex-Lopresti injury, longitudinal forearm stability is lost due to interosseous membrane rupture. The radial head must be preserved or replaced (radial head arthroplasty) to prevent proximal migration of the radius and chronic wrist pain. Radial head excision is absolutely contraindicated.
Question 398
Topic: Elbow & Forearm
A 45-year-old male sustains a terrible triad injury to the elbow. During surgical management, which of the following sequences of repair provides the most biomechanically sound restoration of stability?
Correct Answer & Explanation
. Coronoid fixation, radial head fixation/replacement, LCL repair
Explanation
The standard surgical algorithm for a terrible triad injury involves repairing structures from deep to superficial, or "inside-out". The sequence is typically: 1) Coronoid fixation, 2) Radial head fixation or arthroplasty, 3) LCL complex repair to the lateral epicondyle. If the elbow remains unstable after these steps, the MCL can be repaired or an external fixator applied.
Question 399
Topic: Elbow & Forearm
A patient presents with a history of recurrent elbow clicking and a sense of instability when pushing up from a chair. A lateral pivot-shift test of the elbow is positive. This condition is primarily caused by insufficiency of which of the following structures?
Correct Answer & Explanation
. Lateral ulnar collateral ligament (LUCL)
Explanation
Posterolateral rotatory instability (PLRI) of the elbow is typically caused by injury or insufficiency of the lateral ulnar collateral ligament (LUCL). The LUCL is the primary restraint to posterolateral rotatory subluxation of the radiocapitellar joint. Patients often describe symptoms when applying axial load, valgus stress, and supination (e.g., pushing off a chair).
Question 400
Topic: Elbow & Forearm
When performing a two-incision repair for a distal biceps tendon rupture (modified Morrey approach), which of the following nerves is at the greatest risk of injury during the creation of the posterior bone tunnel in the radial tuberosity?
Correct Answer & Explanation
. Posterior interosseous nerve (PIN)
Explanation
The two-incision approach for distal biceps repair was developed to decrease the risk of injury to the radial nerve/PIN seen in a single-incision anterior approach. However, if the forearm is not kept in maximal pronation during the creation of the posterior bone tunnel (when exiting the ulna/radius posterolaterally), the PIN can wrap around the radial neck and be injured. Maximal pronation moves the PIN away from the surgical field.
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