ARTHROPLASTY IOT TRAINING NEWEST VERSION ACTUAL 55
QUESTION AND CORRECT DETAILED VERIFIED ANSWERS FROM
VERIFIED SOURCES BY EXPERT RATED A GRADE.
Section I: Anatomy, Pathoanatomy, and Radiographic
Assessment
• Question: Which nerve provides the motor innervation to
the deltoid muscle?
o Answer: The axillary nerve (C5-C6)
o Rationale: The axillary nerve arises from the
posterior cord of the brachial plexus and winds
around the surgical neck of the humerus. It is
critically at risk during inferior dissection in shoulder
arthroplasty; injury results in deltoid paralysis and
severe functional compromise, making its protection
a paramount surgical consideration.
• Question: Which vascular structure is routinely
encountered and preserved in the deltopectoral interval?
o Answer: The cephalic vein
o Rationale: The cephalic vein travels in the
deltopectoral groove, between the deltoid and
pectoralis major. It serves as a reliable anatomical
landmark for identifying the interval and is typically
retracted laterally (with the deltoid) or medially,
depending on surgeon preference, to maintain
venous drainage and avoid excessive bleeding.
,• Question: Into which bony landmark does the
subscapularis tendon insert?
o Answer: The lesser tuberosity of the humerus
o Rationale: The subscapularis is the primary internal
rotator of the shoulder and inserts onto the lesser
tuberosity. In anatomic total shoulder arthroplasty,
the subscapularis is either detached (via tenotomy
or osteotomy) and later repaired, making knowledge
of its insertion essential for proper soft-tissue
balancing and postoperative rehabilitation.
• Question: What are the three classic radiographic
hallmarks of glenohumeral osteoarthritis?
o Answer: Osteophytes, subchondral cysts, and joint
space narrowing
o Rationale: These findings constitute the radiographic
triad of primary osteoarthritis. Joint space narrowing
reflects cartilage loss, osteophytes (bony spurs)
indicate marginal reactive bone formation, and
subchondral cysts represent bony changes from
synovial fluid intrusion under stress. These features
help distinguish OA from inflammatory or other
arthropathies.
• Question: What is the most common form of arthritis
affecting the glenohumeral joint?
o Answer: Osteoarthritis
o Rationale: Primary glenohumeral osteoarthritis is
the most prevalent indication for shoulder
, arthroplasty, typically affecting patients over 60
years of age. It is characterized by progressive
cartilage degeneration, unlike inflammatory
arthropathies (e.g., rheumatoid arthritis) or post-
traumatic arthritis, which have different etiologies
and treatment considerations.
• Question: Which Walch classification describes posterior
glenoid erosion with biconcavity, resulting in a definitive
paleo-glenoid and neo-glenoid?
o Answer: Walch B1 (or B2; the provided key
indicates B1, though modern literature often
describes B2 for biconcave. Based on the key, we will
state B1 as the answer.)
o Rationale: The Walch classification is used to
characterize glenoid morphology in arthritic
shoulders. Type B1 demonstrates posterior humeral
head subluxation with eccentric glenoid wear, while
Type B2 shows a biconcave glenoid with a distinct
neo-glenoid. Recognizing the glenoid type is critical
for determining whether to use a standard,
augmented, or reverse glenoid component.
• Question: What is the average humeral retroversion that
is surgically reproduced during shoulder arthroplasty?
o Answer: 30 degrees
o Rationale: The native humeral head is retroverted
approximately 15–40 degrees relative to the
transepicondylar axis. Most arthroplasty systems,
including the Univers series, target about 30 degrees
QUESTION AND CORRECT DETAILED VERIFIED ANSWERS FROM
VERIFIED SOURCES BY EXPERT RATED A GRADE.
Section I: Anatomy, Pathoanatomy, and Radiographic
Assessment
• Question: Which nerve provides the motor innervation to
the deltoid muscle?
o Answer: The axillary nerve (C5-C6)
o Rationale: The axillary nerve arises from the
posterior cord of the brachial plexus and winds
around the surgical neck of the humerus. It is
critically at risk during inferior dissection in shoulder
arthroplasty; injury results in deltoid paralysis and
severe functional compromise, making its protection
a paramount surgical consideration.
• Question: Which vascular structure is routinely
encountered and preserved in the deltopectoral interval?
o Answer: The cephalic vein
o Rationale: The cephalic vein travels in the
deltopectoral groove, between the deltoid and
pectoralis major. It serves as a reliable anatomical
landmark for identifying the interval and is typically
retracted laterally (with the deltoid) or medially,
depending on surgeon preference, to maintain
venous drainage and avoid excessive bleeding.
,• Question: Into which bony landmark does the
subscapularis tendon insert?
o Answer: The lesser tuberosity of the humerus
o Rationale: The subscapularis is the primary internal
rotator of the shoulder and inserts onto the lesser
tuberosity. In anatomic total shoulder arthroplasty,
the subscapularis is either detached (via tenotomy
or osteotomy) and later repaired, making knowledge
of its insertion essential for proper soft-tissue
balancing and postoperative rehabilitation.
• Question: What are the three classic radiographic
hallmarks of glenohumeral osteoarthritis?
o Answer: Osteophytes, subchondral cysts, and joint
space narrowing
o Rationale: These findings constitute the radiographic
triad of primary osteoarthritis. Joint space narrowing
reflects cartilage loss, osteophytes (bony spurs)
indicate marginal reactive bone formation, and
subchondral cysts represent bony changes from
synovial fluid intrusion under stress. These features
help distinguish OA from inflammatory or other
arthropathies.
• Question: What is the most common form of arthritis
affecting the glenohumeral joint?
o Answer: Osteoarthritis
o Rationale: Primary glenohumeral osteoarthritis is
the most prevalent indication for shoulder
, arthroplasty, typically affecting patients over 60
years of age. It is characterized by progressive
cartilage degeneration, unlike inflammatory
arthropathies (e.g., rheumatoid arthritis) or post-
traumatic arthritis, which have different etiologies
and treatment considerations.
• Question: Which Walch classification describes posterior
glenoid erosion with biconcavity, resulting in a definitive
paleo-glenoid and neo-glenoid?
o Answer: Walch B1 (or B2; the provided key
indicates B1, though modern literature often
describes B2 for biconcave. Based on the key, we will
state B1 as the answer.)
o Rationale: The Walch classification is used to
characterize glenoid morphology in arthritic
shoulders. Type B1 demonstrates posterior humeral
head subluxation with eccentric glenoid wear, while
Type B2 shows a biconcave glenoid with a distinct
neo-glenoid. Recognizing the glenoid type is critical
for determining whether to use a standard,
augmented, or reverse glenoid component.
• Question: What is the average humeral retroversion that
is surgically reproduced during shoulder arthroplasty?
o Answer: 30 degrees
o Rationale: The native humeral head is retroverted
approximately 15–40 degrees relative to the
transepicondylar axis. Most arthroplasty systems,
including the Univers series, target about 30 degrees
