Ch 51 - Fractures of the Humerus Flashcards

1
Q

What is anatomically unique about the feline humerus in comparison to the canine?

A
  • Supracondylar foramen, through whicha branch of the brachial artery and median nerve run
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2
Q

How can you best assess nerve function in a humeral fracture?

A
  • toe pinch and skin prick
  • If cutaneous sensation is present, will usually regain motor function in 1-6wk
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3
Q

What is the tricipital line?
What is the deltoid tuberosity?

A
  • Tricipital line: A bony ridge extending from the humeral head cranially and distally toward the deltoid tuberosity. Origin of the lateral head of the triceps. Bone cranial and proximal is generally cancellous
  • Deltoid tuberosity: The insertion point for the deltoideus muscle
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4
Q

What are the two sides of the humeral condyle called?

A
  • Medial: the trochlea - articulates with the trochlear notch of the ulna
  • Lateral: The capitulum - smaller, articulates with the radial head
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5
Q

What percentage of fractures of the humerus are proximal, diaphyseal, supracondylar and condylar in cats and dogs?

A
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6
Q

When does the proximal humeral physis fuse with the metaphysis?

A
  • Dog: 7.5 - 12m
  • Cat: 19 - 26m
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7
Q

At what angle do the humeral head and the greater tubercle fuse?

A

102 degrees

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8
Q

What are the fixation options of a proximal physeal fracture if the physis is complete?

A
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9
Q

What are the fixation options of a proximal physeal fracture if the physis has split between the humeral head and the greater tubercle??

A
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10
Q

What are some potential underlying disease processes of a proximal metaphyseal fracture?

A
  • Nutritional secondary hyperparathyroidism
  • Neoplasia
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11
Q

Where should an IM pin be aimed towards in a dog?
What is the recommended size?

A
  • Aimed towards or inserted into the medial aspect of the humeral condyle to increase bone purchase and length
  • Optimal pin diameter 36 - 45% of the medullary canal diameter observed from a lateral radiograph, measured at the 80th percentile of humeral length
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12
Q

What percentage of nondirected retrograde IM pins penetrate the shoulder?

A

20%

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13
Q

What are the most common ESF configurations for the humerus?

A
  • Type I
  • Modified type I/II
  • ESF tied into IM pin

Usually placed on craniolateral surface

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14
Q

What is the tension surface of the humerus?

A
  • Craniolateral surface proximally
  • Caudomedial surface distally
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15
Q

On which side of the humeral condyle is plate application easier?

A

Medial - straighter epicondylar crest

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16
Q

What is a supracondylar fracture?
What are the repair options?

A

A fracture which communicates with the supracondylar foramen but not with the articular surface
Repair options:
- Cross pins or Rush pinning
- Unilateral or bilateral plate
- ESF - modified type I/II

17
Q

When do the medial and lateral aspect of the condyle fuse together?
When does the condyle fuse with the metaphysis?

A
  • Fuse together: 85d (3m)
  • Fuse to metaphysis: 5.5 - 6m
18
Q

Which aspect of the condyle is fractures more frequently?

A
  • Lateral (34 - 67%) (SHIV)
  • Followed by T/Y (25.9 - 35%)
  • Medial (6.9 - 11%)
19
Q

How much of the growth of the humerus is the distal growth plate responsible for?

A

20%

20
Q

What are the recommended landmarks for transcondylar screw placement?

A
  • Enter craniodistal to lateral epicondyle and exit at similar location on medial side
  • Parallel to articular surface
  • Perpendicular to fracture line
21
Q

What adjunctive fixation options are there after transcondylar screw placement for a lateral condylar fracture?

A
  • Antirotation pin
  • Supracondylar screw
  • Lateral epicondylar plate
22
Q

What is the complication rate of repair of an olecranon osteotomy?

A

up to 37%

23
Q

How ofter are other elbow diseases (eg FMCP) present in dogs with IOHC

A

23.5 - 25%

24
Q

What radiograph projection can aid in diagnosis of IOHC

A

15 degree craniomedial caudolateral oblique

25
Q

What techniques can be implemented to improve healing in IOHC

A
  • Screw combined with transcondylar bone tunnels to allow vascular ingrowth
  • Autogenous cancellous bone graft
  • Fenestrated tubular screw

23% have implant fialure and loss of reduction

26
Q

At what angle do the humeral head and the greater tubercle fuse?

A

102 degrees