Ch 52 - Surgical Diseases of the Elbow Flashcards

1
Q

List the extensor muscles of the elbow joint
What innervated these muscles?

A

Extensors are innervated by the radial nerve and include:
- Triceps brachii
- Tensor fascia antibrachii
- anconeus muscle

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2
Q

List the main flexors of the elbow joint and the associated nerve

A
  • Biceps brachii - musculocutaneous n
  • brachialis m - musculocutaneous n
  • Extensor carpi radialis - radial n
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3
Q

What is the normal range of motion of the elbow?
At what point of extension does the anconeal process articulate with the olecranon fossa?

A

Normal range of motion 130 deg
- 36 flexion
- 165 extension
- At 135deg, anconeal process articulates with olecranon fossa

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4
Q

What is the Campbells test?

A

Testing rotation stability via the collateral ligaments with the elbow and carpus held at 90deg

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5
Q

What are the three regions of conctact in the elbow?

A
  • Craniolateral aspect of anconeal process
  • Radius
  • Medial coronoid process
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6
Q

How much of the weight through the elbow goes through the radial head?

A

51%

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7
Q

Which direction is most common for traumatic elbow luxation? Why?
What position does the elbow need to be in to allow for luxation?

A

Lateral (92 - 100%)
- Relatively large humeral trochlea
- MCL is inherently weaker

Elbow must be flexed beyond 45 degrees to unlock the anconeal process from the olecranon fossa

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8
Q

What percentage of dogs with traumatic elbow luxation will have concurrent collateral ligament damage?

A

18 - 50%

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9
Q

What approach is recommended for open reduction of elbow luxation?

A

Caudolateral

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10
Q

What are the options for post-op immobilisations after elbow reduction?

A
  • Spica splint
  • ESF (connecting bars can be replaced by tight elastic bands to allow some early motion)
  • Potentially also the transarticular fixation (screw or pin)
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11
Q

What are the three types of congenital elbow luxation?

A
  • Type I: Humeroradial
  • Type II: Humeroulnar
  • Type III: Combined
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12
Q

How do you treat Type I humeroradial luxation?

A
  • Oblique osteotomy or wedge ostectomy of radius with bone plate or ESF
  • Reduction maintained with temporary transarticular pin or intraosseous screws between radius and ulna
  • Spica spint or carpal flexion bandage
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13
Q

What breed of dogs have the highest odds ration of UAP?
What percentage of dogs with UAP will also have FMCP?
How often is UAP bilateral?

A
  • Bernese Mt Dogs and Mastiffs
  • 13 - 30% have concurrenct FMCP
  • Bilateral in 20 - 35%
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14
Q

Define positive and negative radioulnar incongruence

A
  • Positive: Ulna longer than the radius
  • Negeative: Radius longer than ulna
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15
Q

At what age does the anconeal process growth plate fuse?

A
  • 14-15wk in Greyhounds
  • 16-20wk GSD
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16
Q

What are the Tx options for UAP?

A
  • Anconeal process removal (owners satisfied but only 50% free of lameness)
  • Reattachment (dogs under 24 weeks with normal trochlear notch, 60% fusion 2-6m)
  • Ulnar osteotomy/ostectomy
  • Reattachment and ulnar osteotomy/ostectomy (best outcome: fusion 93%)
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17
Q

What are some guidelines for an ulnar osteotomy for the Tx of UAP?

A
  • Most successful in dogs under 7m with firmly attached, non-displaced anconeal process
  • Osteotomy located 30-60mm distal to articular surface
  • Bi-oblique: proximocaudolateral to distocraniomedial at 40-50 degrees to long axis
  • +/- IM pin
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18
Q

What breeds are predisposed to flexor entheseopathy?

A

Labradors, GSD, English Setter

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19
Q

What percentage of flexor entheseopathy is primary?

A

15 - 35%

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20
Q

What test can be performed to test for pain associated with flexor entheseopathy?

A

Extending the carpus while holding the elbow at 90 degrees

21
Q

What are the treatment options for primary flexor entheseopathy?

A
  • Conservative
  • Intra-articular methylpred
  • Tenotomy
  • Partial excision
  • Resection of osseous bodies
22
Q

What breeds are predisposed to FMCP?
What % also have elbow incongruity?
What % is bilateral?

A
  • Labs, GSD, Rottweilers
  • 60% concurrent incongruity
  • Bilateral 25 - 80%
23
Q

Regarding FMCP, at what age can subchondral defects been seen?
At what age are articular cartilgate lesion reported to become visible?

A
  • Subchondral defects 15 weeks
  • Articular cartilage defects 18 weeks

Glycosaminoglycan content depletion of the articular cartilage parallels the subchondrl bone defects.

24
Q

What is thought be the cause of FMCP?

A

Delay of endochondral ossification and biomechanical forces acting on the coronoid
- Overloading may occur due to inconguence, humeroulnar conflict, or joint instability

25
Q

How can negative radioulnar incongruence (short ulna) increase pressure within the medial joint compartment?

A

(Angular-vector-model)
Force from relatively long radius applied to the lateral aspect of humeral condyle resulting in rotatory moment (anconeal process is pivot point), rotating medial aspect of humeral condyle distally , thereby increasing pressure at the medial coronoid process

26
Q

What is the percentage of positive and negative incongruence in elbows with FMCP?

A
  • Positive (short radius) - 45%
  • Negative (short ulna) - 14%
27
Q

Describe the Modified Outerbridge Scoring System

A
  • MOS 1: Cartilage softening anf swelling
  • MOS 2: Partial thickness surface defects, fibrillation
  • MOS 3: Deep fibrillation to subchondral bone
  • MOS 4: Full thickeness cartilage erosion
  • MOS 5: Subchondral bone eburnation
28
Q

What is the synovial fossa?

A

A normal cartilage-free area of the lateral aspect of the trochlear notch, approx half way between tip and radial incisure

29
Q

What is the synovial fossa?

A

A normal cartilage-free area of the lateral aspect of the trochlear notch, approx half way between tip and radial incisure

30
Q

What is the internation elbow working group (IEWG) grading system for developmental elbow disease base on radiographs?

A
  • 0 = Normal elbows
  • 1 = Mild: osteophytes less than 2mm high, subtrochlear sclerosis but trabecular pattern still visible
  • 2 = Moderate: Osteophytes 2-5mm high, obvious subtrochlear sclerosis (no trabecular pattern). RU step 3-5mm, indirect signs of primary lesion
  • 3 =Severe: Osteophytes over 5mm high, RU step over 5mm, obvious primary lesion
31
Q

What radiographic view may increased the sensitivity of FMCP?

A

DMPLO-35 degrees

32
Q

What radiographic view if best used to assess for elbow incongruity?

A

90 degree flexed lateral
- Sensitivity 100% and specificity 70-90% for incongruity over 2mm

33
Q

What is the incidence of false negatives on CT scan for assessment of Elbow Dysplasia?

A

29% - Cannot assess the articular cartilage (MRI can)

34
Q

What is the most common technique for assessing incongruence?

A

The duplicated circle technique

35
Q

What are the 4 types of medial coronoid process shape?
Which is most common in normal elbows?

A
  • Type 1: Round
  • Type 2: Pointed
  • Type 3: Flattened
  • Type 4: Irregular

Type 1 most common in normal elbows
Type 4 indicative of FMCP

36
Q

What limb positioning is more helpful for viewing the medial coronoid process during elbow arthroscopy?
What fluid pump setting are typically used for elbow arthroscopy?

A
  • Abduction and pronation
  • Fluid pump set to 70mmHg (50-100) with rate of 1-1.4L/min
37
Q

During arthroscopy, what positioning is used to assess congruity?

A

Elbow joint in a neutral position at a standing angle of approx 135 degrees

38
Q

During elbow arthrotomy, what procedures can be performed if exposure is suboptimal?

A
  • Osteotomy of medial epicondyle
  • tenotomy of pronator teres
39
Q

What are the reported complication rates of elbow arthroscopy?

A
  • Infection 0.2%
  • Major complication needing additional surgery 4.8%
  • Conversion to open arthrotomy 5%
  • Iatrogenic superficial cartilage injury 15%
40
Q

What materials are used for the SynACart synthetic osteochondral transplant?

A
  • Titanium mesh base
  • Thermoplastic polycarbonate urethane surface
41
Q

What are some recommendations/guidelines for a dynamic distal ulnar ostectomy? (DDUO)

A
  • Only effective in young puppies (4-6m)
  • Performed subperiosteally, removing 4-5mm, approx 2-3cm proximal to distal physis
  • Preserve periosteal envelope to prevent synostosis
42
Q

What are the recommendations for performing a bi-oblique proximal ulnar osteotomy?

A
  • Mean angle of 45° caudal to cranial
  • Mean angle of 48° lateral to medial
  • Interosseous membrane and most proximal portion of interosseous ligament should be elevated to allow translation
43
Q

What movement does a PAUL produce?

A

Mild abduction, mild caudal tipping and mild axial rotation of the proximal segment

44
Q

What is a PURO?

A

Proximal Ulnar Rotating Osteotomy
- 30 deg external rotation of proximal segment
- Decreased mean and peak contact pressure by 10% in medial compartment
- Increased by 25% in lateral compartment

45
Q

What procedure is depicted in this radiograph?

A

Sliding Humeral Osteotomy (SHO)

46
Q

What are the three approach options for a Canine Unicompartmental Elbow (CUE) Arthroplasty?

A
  • Medial arthrotomy with tenotomy of flexor tendons and desmotomy of MCL
  • Osteotomy of medial epicondyle
  • Caudomedial approach with osteotomy of olecranon ridge
47
Q

What are the Canine Unicompartmental Elbow (CUE) implants made of?

A
  • 4-6mm diameter polyethylene plug into denuded medial coronoid process
  • “figure 8” shaped cobalt chromium prosthesis into apposing humeral trochlea

Humeral element is implanted slightly proud

48
Q

What is the incidence of false negatives on CT scan for assessment of Elbow Dysplasia?

A

29% - Cannot assess the articular cartilage (MRI can)