This practice set contains high-yield board review questions covering key concepts in Nerve & Tendon. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
Question 921
Topic: Nerve & Tendon
The ulnar nerve is frequently entrapped at the elbow. Which of the following structures normally forms the primary roof of the cubital tunnel?
Correct Answer & Explanation
. Osborne's ligament
Explanation
The roof of the cubital tunnel is formed by the cubital tunnel retinaculum (often referred to as Osborne's ligament or fascia), which spans from the medial epicondyle to the olecranon process. The floor is composed of the medial collateral ligament (MCL) and joint capsule. The Arcade of Struthers is a distinct fascial band located ~8 cm proximal to the medial epicondyle.
Question 922
Topic: Nerve & Tendon
In the context of elbow osteoarthritis, what is the most common nerve entrapment syndrome observed?
Correct Answer & Explanation
. Ulnar nerve at the cubital tunnel
Explanation
Ulnar nerve entrapment at the cubital tunnel is the most common nerve compression syndrome associated with elbow osteoarthritis. This is often due to osteophyte formation around the medial epicondyle and cubital tunnel, valgus deformity of the elbow, or chronic friction/tension on the nerve caused by the degenerative changes and altered mechanics of the joint. The other nerve entrapments listed are less commonly associated directly with the degenerative process of elbow OA.
Question 923
Topic: Nerve & Tendon
A 65-year-old female presents with advanced elbow osteoarthritis and significant ulnar neuropathy. During surgical planning for an elbow arthroplasty, the surgeon anticipates the need for ulnar nerve management. Which statement regarding ulnar nerve management in elbow OA surgery is most accurate?
Correct Answer & Explanation
. Osteophytes around the cubital tunnel should be removed, and if the nerve is mobile, decompression may suffice.
Explanation
Osteophytes around the cubital tunnel can directly compress the ulnar nerve or alter its mechanics. If the nerve is mobile and the compressive osteophytes are removed, a simple in situ decompression may be sufficient. Prophylactic transposition is not universally recommended in all cases; decision-making depends on preoperative symptoms, nerve stability, and planned surgical approach. Anterior transposition (subcutaneous, submuscular, or intramuscular) is a common and effective technique when decompression alone is insufficient or the nerve is unstable, or when performing a major surgical procedure such as TEA, and is not avoided due to increased scarring risk, but rather used to place the nerve in a less constrained, more protected position. Ulnar nerve symptoms in elbow OA can be due to a combination of direct compression by osteophytes, traction from valgus deformity or altered joint mechanics, and friction/impingement. Postoperative immobilization protocols vary, but strict prolonged immobilization is not typically used solely to prevent re-entrapment; early motion is often encouraged.
Question 924
Topic: Nerve & Tendon
In patients undergoing elbow arthroscopy for osteoarthritis, which anatomical structure is at highest risk of iatrogenic injury during portal placement, particularly anterior portals?
Correct Answer & Explanation
. Brachial artery
Explanation
The brachial artery and median nerve lie anteriorly in close proximity to the joint capsule, making them highly susceptible to injury during the placement of anterior portals (e.g., anteromedial portal) if insufficient care is taken or if the elbow is not in an adequately flexed position. The ulnar nerve is at risk posteriorly and medially. The radial nerve and its posterior interosseous branch are at risk with lateral portals, but the brachial artery is a more critical structure immediately anteriorly. The medial and lateral antebrachial cutaneous nerves are more superficial and, while at risk, are less critical than the brachial artery or median nerve in terms of neurovascular damage.
Question 925
Topic: Nerve & Tendon
When performing open debridement for elbow osteoarthritis, what is a potential advantage of the medial approach with medial epicondylar osteotomy compared to a posterior approach with olecranon osteotomy?
Correct Answer & Explanation
. Avoidance of triceps mechanism disruption
Explanation
The medial approach with medial epicondylar osteotomy offers excellent exposure to the anterior and posterior compartments while preserving the triceps mechanism. This approach involves detaching the common flexor origin and ulnar nerve from the medial epicondyle, which is then osteotomized and reflected. While it exposes the medial side well, its primary advantage over an olecranon osteotomy (which necessarily disrupts the triceps) is the preservation of the extensor mechanism. It does not necessarily improve exposure of the radiocapitellar joint more than other approaches or reduce the risk of ulnar nerve injury (which is actually directly addressed). It provides good visualization of both fossae (similar to olecranon osteotomy) and allows access to anterior contractures, but the key differentiating factor mentioned is triceps preservation.
Question 926
Topic: Nerve & Tendon
Which of the following conditions is most likely to be confused with early elbow osteoarthritis due to similar clinical presentation, particularly in athletes?
Correct Answer & Explanation
. Posterior impingement syndrome (without frank OA)
Explanation
Posterior impingement syndrome of the elbow, often seen in throwing athletes, presents with pain and mechanical block at terminal extension due to stress-induced bone formation and soft tissue hypertrophy, similar to early posterior elbow OA. While it can be a precursor to OA, in its early stages, it can be a distinct entity without significant degenerative changes. Cubital tunnel syndrome primarily presents with ulnar nerve symptoms. Lateral epicondylitis presents with pain at the common extensor origin. Olecranon bursitis involves swelling over the olecranon. Rheumatoid arthritis is an inflammatory condition with distinct systemic features, though it can mimic OA with joint pain and stiffness.
Question 927
Topic: Nerve & Tendon
Which factor is most strongly associated with a poor prognosis for open debridement and osteophyte excision in elbow osteoarthritis?
Correct Answer & Explanation
. Post-traumatic etiology with significant articular cartilage loss
Explanation
Open debridement and osteophyte excision are most effective for mechanical symptoms and bony impingement in primary OA or mild to moderate post-traumatic OA. However, if there is significant articular cartilage loss, especially post-traumatic, the underlying degenerative process is more advanced, and simply removing osteophytes and loose bodies will not adequately address the pain from bone-on-bone articulation. This makes significant articular cartilage loss, especially in post-traumatic cases, a strong predictor of poor prognosis for debridement alone, often indicating the need for more reconstructive options like arthroplasty. Younger age can sometimes be a predictor of faster recurrence or progression if the underlying cause (e.g., throwing) is not modified. Associated cubital tunnel syndrome can be addressed concurrently. A flexion contracture less than 15 degrees suggests less severe stiffness. Absence of loose bodies doesn't inherently worsen prognosis for debridement.
Question 928
Topic: Nerve & Tendon
What is the primary objective of performing ulnar nerve transposition during an elbow arthroplasty for osteoarthritis?
Correct Answer & Explanation
. To relieve compression and/or tension on the nerve from bony changes or altered joint mechanics.
Explanation
Ulnar nerve transposition, typically anteriorly, is performed during elbow arthroplasty primarily to relieve existing compression or tension on the nerve (if preoperative neuropathy is present) or to prevent postoperative compression/tension/subluxation from the altered anatomy, osteophyte removal, or implant placement. It places the nerve in a less constrained, more protected position. It does not prevent heterotopic ossification, directly improve motor function unless the nerve was severely compromised, facilitate wound closure, or enhance regeneration after injury (though it can optimize conditions for recovery). The goal is to prevent or treat cubital tunnel syndrome.
Question 929
Topic: Nerve & Tendon
A 62-year-old active male underwent open debridement and osteophyte excision for elbow osteoarthritis. Two months post-op, he continues to have a significant flexion contracture (loss of extension) and painful terminal extension. Radiographs show minimal residual osteophytes. What is the most likely cause of his persistent stiffness?
Correct Answer & Explanation
. Inadequate posterior capsular release or ongoing capsular contracture
Explanation
Given that the patient underwent osteophyte excision and radiographs show minimal residual osteophytes, persistent stiffness (especially a flexion contracture) and painful terminal extension are most likely due to inadequate posterior capsular release during the initial surgery or significant postoperative scarring leading to ongoing capsular contracture. While other issues can cause pain, the specific symptom of persistent flexion contracture and painful terminal extension points directly to the posterior compartment's soft tissue structures. Recurrent ulnar nerve compression primarily causes neurological symptoms. Radiocapitellar impingement mainly affects rotation. New loose bodies or triceps tendonitis are less likely to cause a fixed flexion contracture and painful terminal extension immediately post-op following debridement.
Question 930
Topic: Nerve & Tendon
In patients presenting with symptoms of both elbow osteoarthritis and cubital tunnel syndrome, what is the preferred management strategy for the ulnar nerve during an open debridement for OA?
Correct Answer & Explanation
. Address any direct compression (osteophytes) and consider anterior transposition if symptoms are significant or the nerve is unstable.
Explanation
When a patient presents with both elbow OA and cubital tunnel syndrome, the ulnar nerve must be addressed during open debridement. The preferred strategy is to first remove any direct compressive osteophytes around the cubital tunnel. If the nerve is still symptomatic, unstable, or appears to be under significant tension after debridement, then an anterior transposition (subcutaneous or submuscular) should be considered. Ulnar nerve symptoms do not typically resolve spontaneously and often worsen with OA progression or surgical manipulation. Prophylactic neurolysis alone may be insufficient. Medial epicondylectomy is one form of decompression but is not always preferred over transposition. Waiting until severe subluxation is a reactive, rather than proactive, approach for significant symptoms.
Question 931
Topic: Nerve & Tendon
Following an acute elbow dislocation, what is the most common associated neurovascular complication that must be carefully assessed?
Correct Answer & Explanation
. Ulnar nerve palsy
Explanation
While all listed neurovascular structures can be injured during an elbow dislocation, the ulnar nerve is the most commonly affected, particularly with posterior dislocations. Its superficial location posterior to the medial epicondyle makes it vulnerable to stretch or contusion. Radial nerve injury is less common, and median nerve and brachial artery injuries, while serious, are less frequent than ulnar nerve involvement. Anterior interosseous nerve palsy is a specific motor branch of the median nerve and less frequently involved as a standalone primary complication of dislocation.
Question 932
Topic: Nerve & Tendon
A 10-year-old boy falls directly onto his elbow and presents with pain, swelling, and limited motion. Radiographs reveal a displaced supracondylar humerus fracture (Gartland Type III). Neurological examination shows weakness in wrist flexion and thumb/index finger flexion, with sensory loss over the palmar aspect of the index and middle fingers. Which nerve is most likely injured?
Correct Answer & Explanation
. Median nerve
Explanation
The median nerve is the most commonly injured nerve in supracondylar humerus fractures, especially with posteromedial displacement. Weakness in wrist flexion (flexor carpi radialis), thumb flexion (flexor pollicis longus), and index finger flexion (flexor digitorum profundus to index/middle) along with sensory loss in the palmar aspect of the index and middle fingers and thumb indicates median nerve involvement. The anterior interosseous nerve is a motor branch of the median nerve, but the described sensory loss points to a more proximal median nerve injury. Radial nerve injury typically affects wrist and finger extension, while ulnar nerve injury affects intrinsics and sensation to the little finger and ulnar half of the ring finger.
Question 933
Topic: Nerve & Tendon
What is the most common cause of cubital tunnel syndrome?
Correct Answer & Explanation
. Repetitive elbow flexion and extension
Explanation
The most common cause of cubital tunnel syndrome is often considered idiopathic, but repetitive elbow flexion and extension (which increases pressure within the cubital tunnel and stretches the ulnar nerve) is a significant contributing factor and mechanical cause. Other causes include direct trauma, degenerative changes, anconeus epitrochlearis muscle, and a persistent arcade of Struthers, but repetitive motion is a very common mechanism leading to chronic compression or traction neuropathy.
Question 934
Topic: Nerve & Tendon
A patient undergoing an ulnar nerve transposition procedure should be counseled about potential for injury to which nearby structure if dissection is not meticulous?
Correct Answer & Explanation
. Medial antebrachial cutaneous nerve
Explanation
During ulnar nerve transposition (subcutaneous, intramuscular, or submuscular), the medial antebrachial cutaneous nerve (MABCN) is consistently in the surgical field and is at high risk of injury. It provides sensation to the medial forearm. Injury can lead to a painful neuroma or numbness in its distribution. The other listed nerves and artery are generally not in the immediate vicinity of the ulnar nerve transposition, assuming proper surgical technique.
Question 935
Topic: Nerve & Tendon
Which nerve is at greatest risk during an anterior capsular release for elbow flexion contracture?
Correct Answer & Explanation
. Median nerve
Explanation
During an anterior capsular release, particularly if performed from a medial approach, the median nerve is at greatest risk. It lies anterior to the elbow joint and crosses the anterior capsule. The brachial artery is also in close proximity. The ulnar nerve is typically protected posteriorly. The radial nerve is lateral. PIN and AIN are distal branches.
Question 936
Topic: Nerve & Tendon
When performing an ulnar nerve anterior transposition, what is a common complication specific to placing the nerve subcutaneously?
Correct Answer & Explanation
. Persistent pain from superficial positioning
Explanation
When the ulnar nerve is transposed subcutaneously, a common specific complication is persistent pain from its superficial positioning, making it susceptible to direct trauma or pressure. The nerve can also sometimes subluxate back over the epicondyle, although this is less common with proper soft tissue release and fixation. Compression by the arcade of Struthers (proximal to the cubital tunnel) is a cause of compression that needs to be released, not a specific complication of subcutaneous transposition. PIN injury is not related. Brachial artery injury is also not a specific complication of subcutaneous transposition, although always a general risk.
Question 937
Topic: Nerve & Tendon
Which of the following describes the anatomical structure known as the 'arcade of Struthers'?
Correct Answer & Explanation
. A fibrous band extending from the medial head of the triceps to the medial intermuscular septum, potentially compressing the ulnar nerve
Explanation
The arcade of Struthers is a fibrous band or ligamentous structure that extends from the medial head of the triceps to the medial intermuscular septum. It is a potential site of ulnar nerve compression, located approximately 8 cm proximal to the medial epicondyle. It is distinct from the pronator teres arch (median nerve), the arcade of Frohse (PIN), or the annular ligament.
Question 938
Topic: Nerve & Tendon
A 28-year-old construction worker presents with insidious onset of pain and paresthesias in his little finger and ulnar half of the ring finger, particularly at night and with elbow flexion. Tinel's sign is positive at the cubital tunnel. What is the most common cause of cubital tunnel syndrome?
Correct Answer & Explanation
. Compression beneath the aponeurosis of the flexor carpi ulnaris (FCU)
Explanation
The most common site of compression for the ulnar nerve in cubital tunnel syndrome is beneath the aponeurosis of the flexor carpi ulnaris (also known as the cubital tunnel retinaculum or Osborne's ligament). Other potential sites of compression include the arcade of Struthers (proximal to the elbow), subluxation of the nerve, anconeus epitrochlearis, and fibrous bands. Guyon's canal is at the wrist. While direct trauma can cause it, compression by the FCU aponeurosis is the most prevalent anatomical cause of entrapment. Subluxation can contribute but is often a consequence or a coexisting factor with compression.
Question 939
Topic: Nerve & Tendon
Which of the following describes the anatomical landmark for identifying the ulnar nerve during an elbow surgical approach?
Correct Answer & Explanation
. It courses posterior to the medial epicondyle, within the cubital tunnel.
Explanation
The ulnar nerve is consistently located posterior to the medial epicondyle as it passes through the cubital tunnel. This is a critical anatomical landmark for both identification and protection during surgical approaches to the medial elbow. Its position makes it vulnerable to compression and injury. The radial nerve passes through the supinator (arcade of Frohse), and the median nerve is anterior in the cubital fossa.
Question 940
Topic: Nerve & Tendon
Which of the following describes the 'arcade of Frohse' and its clinical significance?
Correct Answer & Explanation
. A fibrous arch formed by the superficial head of the supinator muscle, compressing the posterior interosseous nerve (PIN).
Explanation
The arcade of Frohse is a fibrous arch formed by the superficial head of the supinator muscle. It is a common site of compression for the posterior interosseous nerve (PIN), leading to PIN syndrome, characterized by motor weakness in the finger and thumb extensors without sensory deficits. The cubital tunnel retinaculum (Osborne's ligament) compresses the ulnar nerve. Pronator syndrome involves the median nerve, and the common flexor tendon is involved in medial epicondylitis.
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