Elbow

Question 1

What ligament is responsible for posterolateral rotatory instability and a positive pivot shift test in the elbow?

Answer 1

Lateral Ulnar Collateral Ligament

Question 2

What does the microhistopathology of lateral epicondylitis reveal?

Answer 2

angiofibroblastic hyperplasia, disorganized collagen, and lacks inflammatory cells

Question 3

During what phase of throwing is valgus load on the elbow the highest?

Answer 3

Late cocking, early acceleration

Question 4

What are the two bands of the anterior oblique ligament of the MUCL? And what are their function?

Answer 4

anterior band - primary restraint to valgus stress; isometric strain throughout elbow ROM
posterior band - increasing strain during elbow flexion

Question 5

What are the three components of the MUCL? And which is the primary restraint to valgus stress?

Answer 5

Anterior oblique ligament; posterior ligament, transverse ligament; the anterior oblique band (specifically the anterior band) is the primary restraint to valgus stress

Question 6

What is the origin and the insertion of the anterior oblique ligament of the MUCL?

Answer 6

anteroinferior ridge on medial epicondyle to 2.8 mm distal to the ulna articular margin on the sublime tubercle

Question 7

During what degrees of elbow ROM is the UCL the primary restraint to valgus stress?

Answer 7

30 to 120 degrees

Question 8

What are the risk factors for little league elbow?

Answer 8

> 85 mph pitching speed, more than 8 months of pitching per year, >80 pitches per game, continued pitching despite arm fatigue and pain, participating in showcases

Question 9

What is the orientation of the distal insertion of the long head and short head of the biceps tendon?

Answer 9

The long head of the biceps inserts more proximally while the short head inserts distally at the tuberosity.

Question 10

Where does the anterior oblique bundle of the ulnar collateral ligament insert?

Answer 10

sublime tubercle

Question 11

Which muscle is thought to be the instigator of lateral epicondylitis?

Answer 11

ECRB

Question 12

Where does ECRL originate?

Answer 12

lateral supracondylar ridge

Question 13

What muscles originate on the lateral epicondyle?

Answer 13

extensor carpi radialis brevis, extensor carpi ulnaris, extensor digitorum, extensor digiti minimi, anconeus (shares same attachment site as ECRB)

Question 14

What is the origin and the insertion of ECRB?

Answer 14

anterior aspect of the lateral epicondyle and inserts on the third metacarpal

Question 15

A patient develops posterolateral rotatory instability after arthroscopic debridement for lateral epicondylitis, which structure was injured?

Answer 15

lateral ulnar collateral ligament

Question 16

What is the origin and the insertion of the lateral ulnar collateral ligament?

Answer 16

originates on the lateral epicondyle of the humerus and inserts upon the supinator crest of the ulna.

Question 17

What is the survival rate of total elbow arthroplasty in patients with rheumatoid arthritis at 15 years?

Answer 17

upwards of 90% survival rate at 15 years

Question 18

What is the most common mode of failure of the lateral ulnar collateral ligament associated with an elbow dislocation?

Answer 18

Avulsion off the humeral origin

Question 19

What is the origin of the LUCL?

Answer 19

lateral epicondyle

Question 20

What are the primary static stabilizers of the elbow joint?

Answer 20

ulnohumeral joint, anterior bundle of the MCL, LCL complex (including the LUCL)

Question 21

What are the secondary static stabilizers of the elbow joint?

Answer 21

radiocapitellar joint, the capsule, origins of the common flexor and extensor tendons

Question 22

What are the dynamic stabilizers of the elbow?

Answer 22

muscles that cross the joint - brachialis, anconeus, triceps

Question 23

In extension and axial loading, how much weight is carried through the ulnohumeral joint? and the radiocapitellar joint, respectively?

Answer 23

40% through ulnohumeral joint; 60% through radiohumeral joint

Question 24

Where does the anterior bundle of the medial ulnar collateral ligament attach distally?

Answer 24

Sublime tubercle on the ulna