Conditions of the Elbow

Question 1

list 4 common conditions of the elbow

Answer 1

1. elbow dysplasia (ED)
   -medial coronoid process disease (MCD)
   -osteochrondrosis dissecans (OCD)
   -ununited anconeal process
   -elbow incongruity
2. flexor enthesopahy
3. incomplete ossification of the humeral condyle
4. traumatic elbow luxation

Question 1

what are the 3 joints associated with the elbow?

Answer 1

1. humeroradial joint
2. humeroulnar joint
3. radioulnar joint

all are very tightly fit together with a complex range of motion

Question 2

describe the bones and bony prominences associated with the elbow

Answer 2

1. anconeal process
2. tuber olecrani
3. lateral coronoid process
4. medial coronoid process
5. radial head
6. humeral condyle: one condyle, has a lateral (capitulum) and medial (trochlea) aspect
7. medial epicondyle
8. lateral epicondyle

look at and be able to label both views in notes!

Question 3

describe the ligament support of the elbow

Answer 3

1. medial collateral ligaments
2. lateral collateral ligament
   medial and lateral fan out and have a borad attachment, some to the radius as well
3. anular ligament: wraps around and hugs radius to ulna
4. interosseus membrane and ligament, more distal, help keep radius and ulna together

biceps and brachialis insert below the elbow, cross very closely to the joint

Question 4

describe the neuromuscular anatomy of the elbow

Answer 4

1. all extensors (triceps brachii, tensor fascia antebrachiae, and anconeous) all innervated by radial nerve
2. all flexors (biceps brachii, brachialis- musuclocutaneous n), extensor carpi radalis (radial n)

Question 5

describe the functional anatomy of the elbow

Answer 5

1. mostly functions as a hinge joint (flexion/extension)
2. radioulnar joint allows for pronation/supination: VERY important for cats
3. campbell test: flex elbow at 90 degree angle, then pronate/supinate at the paw to increase the angle of movement at the elbow

Question 6

describe elbow dysplasia

Answer 6

1. catch-all term for developmental elbow disease
2. most common cause of forelimb lameness in dogs
3. young. large, and giant breed dogs, may present as adults (secondary OA, but disease still initiates in young animals as growing)
4. bilateral involvement common, even if only one side is clinical, eval both sides!
5. multifactorial etiology not fully understood but we do know that there is a complicated genetic component (not easy to breed out of a line, just don’t breed clinically affected dogs)

Question 7

what does elbow dysplasia usually involve?

Answer 7

one or several of the following:

1. medial coronoid process disease
2. osteochondritis disease
3. elbow incongruity
4. ununited anconeal process

but can really be any developmental disease of the elbow!

Question 8

how does elbow dysplasia usually present? (2)

Answer 8

1. young dogs (<1 year): primary disease clinical signs (from the flap, or fragmented process, etc.) +/- secondary osteoarthritis
2. older dogs: presenting mostly for signs related to secondary OA, not necessarily for signs related to the primary disease

Question 9

describe medial coronoid process disease

Answer 9

1. most common component of elbow dysplasia
2. exact pathology varies: sclerosis, microfracture, blunting, fissure, fragmentation, cartilage damage, etc.

Question 10

describe clinical signs of medial coronoid process disease

Answer 10

clinical signs
-posture: slight elbow abduction and supination of manus
-gait: variable lameness (usually weight bearing)
-with chronic OA: joint thickening (periarticular fibrosis, osteophytosis), crepitus, decreased ROM

Question 11

describe the exam for medial coronoid process disease

Answer 11

exam:
-variable joint effusion
-pain on elbow hyperextension/hyperflexion
-pain of direct palpation of MCP during elbow flexion and supination of distal limb
-direct palpation of MCP accomplished by placing thumb about a thumb width below medial epicondyle, flex the elbow and supinate the distal limb to compress the medial compartment; good for eliciting more subtle cases!

Question 12

describe diagnosis of medial coronoid process disease

Answer 12

1. radiographs: can be difficult on lateral view, hidden by radial head; high incidence of false negatives!
   -earliest sign is subtrochlear sclerosis
   -poor definition of cranial margin of MCP
2. CT +/- arthroscopy are more
   sensitive/gold standard
   -CT: not invasive, great for eval subchondral bone but not great at eval cartilage

-arthroscopy: minimally invasive, simultaneous treatment (if indicated) is possible
-great for eval cartilage; not always great for subchondral bone
-both CT and arthroscopy may be necessary for a complete eval but must consider iatrogenic risk of articular cartilage damage

Question 13

describe treatment of medial coronoid process disease

Answer 13

controversial!

1. medical management:
   -always recommended bc OA is inevitable
   -same guidelines as OA management +/- joint injections (WEDDS)
2. surgical intervention: case and surgeon dependent
   -arthroscopy is most common: fragment removal or abrasion arthroplasty
   -osteotomy procedures are less common; several kinds but all aim to relieve pressure on medial compartment
   -controversial because unsure about benefit and duration of benefits

Dr. Verpaalen’s takes:
1. subclinical MCP: incidental finding, no pain or lameness, medical management
2. clinical MCP disease with mild/mod OA: more likely to benefit from surgical intervention, rec surgery but be transparent about risks
3. clinical MCP disease with severe OA:
-OA is likely playing a significant role and are less likely to benefit from sx intervention, recommend medical management

Question 14

describe prognosis for MCP disease

Answer 14

1. difficult to define, may improve with medical and/or surgical treatment
2. ALL will develop OA
3. often some residual or recurrent lameness
4. outcome seems to be related to severity of OA

Question 15

describe elbow OCD

Answer 15

1. occurs on the medial aspect of the humeral condyle (trochlea)
2. clinical presentation and diagnosis similar to MCP disease
3. treatment options:
   -medical: always
   -surgical:
   -arthroscopy: flap removal and abrasion arthroplasty +/- cartilage resurfacing techniques
4. prognosis:
   -guarded (worse than with mCP disease alone)
   -dogs may improve with surgery
   -many have residual/progressive lameness

Question 16

describe ununited anconeal process

Answer 16

1. the anconeal process develops from a separate ossification center in large breed dogs
2. normal fusion is at 20-22 weeks of age (5-6 months), but if fusion fails to occur = UAP
3. contributing factors:
   -genetics: large breed dogs, but also reported in small breeds
   -radioulnar incongruity: short ulna
4. clinical consequences:
   -typically present 5-12 mos
   -lameness, EFFUSION (often pronounced), pain on hyperextension, decreased extension
   -osteoarthritis
   -bilateral disease in 20-35% of cases!
5. diagnosis: flexed lateral radiograph
6. treatment options: early intervention recommended to optimize functional outcome and minimize OA progression
   -surgical:
7. reattachment and ulnar osteotomy to relive pressure (preferred if possible, highest success rate if both are combined, minimal AP remodeling once old so prefer to perform in young dogs)
8. excision: consider if AP is malformed or substantial OA (older dogs), can often relieve discomfort, more likely to have residual lameness and more progressive OA than reattachment and ulnar osteotomy
   -medical: should always be instituted, if sole therapy expect more progressive OA due to persistent joint instability

Question 17

describe elbow incongruity

Answer 17

1. often seen in conjunction with other components of ED (MCPD, UAD); contributes to severity of disease and OA progression
2. humeroulnar conflict can lead to kissing lesions of the medial humeral condyle cartilage
3. diagnosis: radiographs, CT and arthroscopy (more sensitive)
4. treatment for radioulnar incongruity: earry intervention recoemmended if possible, ulnar osteotomy (short ulna) or ostectomy (short radius)

Question 18

describe medial compartment disease

Answer 18

inconsistently defined; can either describe any pathology of medial elbow or advanced stages of disease (severe cartilage wear and OA); specify advanced/end-stage MCD

Question 19

describe end-stage elbow osteoarthritis

Answer 19

can be a real challenge, if non-surgical options are exhausted, salvage options include:

-arthrodesis: to eliminate pain and provide reasonable function, patients can do well with some function limitations and marked gait abnormality

-total elbow replacement: complicated and not widely available, not everyone is a good candidate, but good patients can do very well

Question 20

describe flexor enthesopathy

Answer 20

1. several terms describe this condition: ununited medial epicondyle, epicondylitis
2. encompasses pathology of the flexor tendons and their attachments to the medial epicondyle (partial avulsion, enthesophytes, ossified bodies)
3. primary form: occurs in isolation
4. concomitant form: occurs with other elbow pathology
5. clinical signs: similar to medial compartment disease, may or may not be systematic, +/- pain on direct palpation of flexor tendon attachments
6. diagnosis: radiographs/CT
7. treatment: medical management, intra-articular steroid injection, surgical excision
8. prognosis: good for primary form

Question 21

describe IOHC

Answer 21

1. medial and lateral humeral condyle form from separate ossification centers (normally fuse at 2-3 months); failure to fuse = permanent fissure line
2. IOHC = incomplete ossification of humeral condyle
3. breed dispositions: SPANIELS, frenchies, labs

Question 22

describe IOHC presentation, diagnosis, and treatment

Answer 22

presentation:
1. chronic lameness
2. acute condylar fratures: always suspet in adult dogs with NO history of major trauma

2. diagnosis: compare to contalateral elbow!
   radiographs and CT (more sensitive); looking for fissure line
3. treatment:
   -can place a prophylactic screw, but is controversial due to potential complications (implant infection, implant migration)
   -prevent patient jumping on and off things

Question 23

describe traumatic luxation

Answer 23

see other lecture

Question 24

describe congenital elbow luxation

Answer 24

1. usually present with mild clinical signs at 2-5 months
2. type I: radial head luxated (small/large breed)
   type II: ulna luxated (small breeds)
   type III: both radius and ulna luxated (often other ortho abnormalities, worse prognosis)
3. treatment options:
   -conservative management: reasonable if mild clinical signs
   -reduction and surgical stabilization: best if performed early (<5months old, still have more of normal anatomy to work with)
   -arthrodesis- salvage
4. prognosis: variable
   -type I and II fair/good, type III poor