Elbow dysplasia and osteochondrosis

Question 1

Osteochondrosis

Answer 1

Occurs as a result of focal failure of endochondral ossification or abnormal differentiation of cartilage into bone

The result is a thickened area of cartilage in either the epiphysis or metaphysis.

In the epiphysis this cartilage may fissure and partially detach from the underlying subchondral bone resulting in the typical ‘dissecting’ flap seen in osteochondritis dissecans.

Question 2

Aetiology of osteochondrosis

Answer 2

a hereditary factor in the development of osteochondrosis but it is likely that the condition is multifactorial.

Dietary factors clearly identified as increasing risk for juvenile bone and joint diseases are high calories, high absolute calcium and ad libitum feeding.

Owners should be advised NOT to breed from affected animals, their siblings or parents

Question 3

Signalment of osteochondrosis

Answer 3

Commonly occurs in the shoulders, elbows, stifles, and hocks of immature large-breed and giant-breed dogs.

Onset of signs is between 4 months and 10 months of age.

Usually large or giant breeds such as the Labrador retriever, Rottweiler, Bernese mountain dog, Great Dane. The Border Collie is also often affected.

Males are generally affected more commonly than females

Question 4

Clinical signs of oesteochondrosis

Answer 4

Lameness is often insidious in onset, chronic and deteriorates after rest or excessive exercise.

The condition is commonly bilateral.

Affected joints often have a reduced range of motion (ROM) and pain can be elicited by attempts to fully extend (or flex) the joint, there may be joint thickening or effusions.

In bouncy puppies physical examination findings may be subtle such as only slight withdrawal of the elbow on attempts at full flexion or extension - if in doubt proceed to radiography

Question 5

Radiorgaphy of osteochondrosis

Answer 5

Changes are fairly specific for each joint but include areas of thickened cartilage (seen as subchondral bone defects), mineralised OCD flaps or joint mice, osteocartilaginous fragments and peripheral osteophyte formation.

In the early stages of the disease signs can be subtle so if the index of suspicion is still high it can be useful to repeat radiography in 4-6 weeks.

Question 6

Therapy for osteochondrosis

Answer 6

Varies dependent on the joint involved and severity of the disease.

Generally in the larger joints such as the shoulder and stifle the thickened flap of cartilage is removed.

The subchondral bone defect may heal with fibrocartilage but this may be influenced by size of lesion, weight bearing and age.

Question 7

How can healing be improved after therapy for osteochondrosis

Answer 7

Forage - drilling small holes in the subchondral bone to allow the influx of blood vessels….healing by fibrocartilage formation

Joint resurfacing: Osteochondral autograft or allograft (complications) vs Joint resurfacing implants

Regenerative medicine

Chondrectomy - ensure all under run cartilage is removed and margins of defect are vertical

the use of polysulphated glycosaminoglycans or hyaluronic acid may be beneficial

early controlled weight bearing encourages healing – e.g. 4-6 weeks of lead only exercise

Question 8

Prognosis of osteochondrosis

Answer 8

This varies on the joint affected.

After surgery for shoulder OCD the prognosis is very good, however the prognosis for a full return to function for hock and elbow osteochondrosis is much less likely.

Question 9

Site of osteochondrosis in the shoulder

Answer 9

Caudal humeral head

Question 10

Site of osteochondrosis in the elbow

Answer 10

Medial humeral condyle

Question 11

Site of osteochondrosis in the carpus

Answer 11

Retained cartilaginous sores - distal ulna

Question 12

Site of osteochondrosis in the stifle

Answer 12

Lateral (or medial) condyle - femur

Question 13

Site of osteochondrosis in the hock

Answer 13

Medial (or lateral) talar ridge - talus

Question 14

Signalment of shoulder osteochondrosis

Answer 14

Giant breeds and Border Collie

Age at onset - 4-8months

Sex - females more commonly affected than males

Question 15

Clinical signs of shoulder osteochondrosis

Answer 15

uni or bilateral forelimb lameness,

shoulder muscle atrophy

pain on shoulder extension

Question 16

Radiography of shoulder osteochondrosis

Answer 16

mediolateral view of both shoulders (supinated or pronated views rarely indicated)

subchondral defect with flattening of caudal humeral head

mineralised cartilage flap

mineralised joint mouse

DJD - osteophyte formation on caudal glenoid and humeral head

Question 17

Treatment of shoulder osteochondrosis

Answer 17

Conservative - with small lesions and detached lesions then conservative treatment consisting of 4 weeks rest and NSAIDs as necessary may be successful.

Surgery - surgical debridement of detached flap or joint mice in bicipital groove

Question 18

Surgical approach to shoulder osteochondrosis

Answer 18

the caudal approach gives adequate exposure with minimal trauma.

1. Incise from mid scapular spine to the proximal humerus
2. Dissect through subcutaneous fascia and fat and between the scapular part of the deltoid and the long and lateral heads of the triceps
3. Reflect the caudal circumflex humeral artery and vein and the brachial nerve with 2 pairs of blunt gelpi retractors
4. Identify the caudal glenoid and humeral head by palpation and manipulation of the shoulder and incise through the joint capsule in a DV direction
5. Use a Hohman retractor and strong internal rotation of the joint to expose the OCD lesion

Question 19

Prognosis of surgery for shoulder osteochondrosis

Answer 19

90% of dogs will respond favourably to surgical debridement with alleviation of lameness

Question 20

Post operative management for shoulder osteochondrosis

Answer 20

strict rest / short lead walks for four weeks

Question 21

Complications of surgery for shoulder osteochondrosis

Answer 21

failure to remove the whole flap especially medially,

seroma formation (10%)

Question 22

Stifle osteochondrosis

Answer 22

Of the four joints most commonly affected with osteochondrosis the stifle is the least commonly affected.

The lesion is usually seen on the lateral condyle.

Question 23

Signalment of stifle osteochondrosis

Answer 23

giant breeds most commonly affected.

Present between age 4 – 10mths.

Males and females both affected.

Question 24

Presenting sign with stifle osteochondrosis

Answer 24

hind limb lameness chronic

Question 25

Physical examination of stifle osteochondrosis

Answer 25

stifle effusion and pain on full extension and flexion.

May be concurrent problems such as cranial cruciate rupture or patella luxation

Investigations – radiography, mediolateral and craniocaudal views.

Flattening of the medial aspect of the lateral condyle with sclerosis of the underlying bone may be seen on both views but the craniocaudal view is more useful.

Question 26

Investigations of stifle osteochondrosis

Answer 26

radiography, mediolateral and craniocaudal views.

Flattening of the medial aspect of the lateral condyle with sclerosis of the underlying bone may be seen on both views but the craniocaudal view is more useful.

Question 27

Treatment options for stifle osteochondrosis

Answer 27

may be detected as an incidental finding when other stifle problems are present e.g. in an older dog with CCL disease.

In cases where there is obvious lameness, effusion and pain present then an arthrotomy and debridement of loose cartilage flaps may be beneficial.

Alternatively a techique of bone grafting can be performed (OATS) whereby a block of bone capped cartilage is taken from a non weight bearing region of the knee and placed in the area of bone affected by OCD.

Question 28

Post operative care for stifle osteochondrosis

Answer 28

restricted exercise for 4 weeks after surgery.

Breeding from affected animals is not recommended

Question 29

Hock osteochondrosis

Answer 29

The hock joint is less commonly affected by osteochondrosis than the elbow or shoulder joint.

Because of this less is known about the prognosis, and guidelines on management are less well defined.

The lesions are most commonly seen on the medial talar ridge and much less frequently on the lateral talar ridge.

Question 30

Signalment of hock osteochondrosis

Answer 30

Rottweillers, Mastiffs, Labradors and Bull Terriers

Males and females affected.
Possibly males over represented

Animals present from 5mths to a year of age

Question 31

History of hock osteochondrosis

Answer 31

Chronic lameness

Question 32

Gait evaluation of hock osteochondrosis

Answer 32

affected animals have a very upright stance to their hocks to the extent of almost being hyperextended

Question 33

Physical examination of hock osteochondrosis

Answer 33

there will be a reduction in flexion of the hock, with crepitus and pain on manipulation.

A palpable effusion or thickening is usually present

Question 34

Investigations of hock osteochondrosis

Answer 34

Radiography - mediolateral and dorsoplantar views are usually sufficient to show the lesion.

Other views that may be useful include those that skyline the talar ridges such as the flexed dorsoplantar view, or oblique views if lateral lesions are suspected.

Changes seen on radiographs include all or some of the following: flattening of the medial talar ridge, an increase in joint space, mineralised flaps, osteophytes and peri-articular swelling.

Question 35

Treatment options for hock osteochondrosis

Answer 35

similar to elbow OC decisions as to whether to treat the condition surgically or conservatively should be made after consideration of a variety of factors.

If the animal is obviously lame, painful, with minimal arthritis or if there is an obvious flap then surgery may be indicated.

If the lesion is small, lameness is minimal or absent or there is well established osteoarthritis then conservative treatment may be more suitable.

Question 36

Conservative mangement of hock osteochondrosis

Answer 36

minimal lead only exercise for 4 weeks.

NSAIDs for the first two weeks.

Then make a gradual return to normal exercise.

Question 37

Surgical management of hock osteochondrosis

Answer 37

An approach to the tibiotarsal joint is made by an incision through the joint capsule caudal to the medial collateral ligament.

By flexing and extending the joint intra operatively most of the caudal 50% of the medial talar ridge can be accessed.

Loose flaps of cartilage are debrided and the joint flushed.

Question 38

Post operative management for hock osteochondrosis

Answer 38

Post operatively animals should be managed with rest similar to the conservative management described above.

Bandaging for ten days post op may also be beneficial – reducing pain and swelling.

Question 39

Prognosis of hock osteochondrosis

Answer 39

guarded.

Arthritis will develop and in very severe cases arthrodesis may be indicated.

Question 40

Elbow dysplasia

Answer 40

An abnormal development of the elbow joint that occurs in dogs during the growth phase.

Question 41

Consequence of elbow dysplasia

Answer 41

joint incongruity causing a variety of different problems (more than one of these problems may occur in the same elbow joint at the same time):

• Fragmented medial coronoid process ( FMCP)
• Osteochondritis dissecans (OCD) of humeral condyle
• Un-united anconeal process (UAP)
• Joint (radio-ulnar) incongruity

Question 42

Signalment of elbow dysplasia

Answer 42

Large and giant breeds

Smaller chondrodystrophic breeds

Bilateral disease 25-80%

Males 2x more common

6-12 months of age (older dogs also diagnosed with ED)

Question 43

Aetiology of elbow dysplasia

Answer 43

Multifactorial

Clear genetic association

As with hip dysplasia, elbow dysplasia is a polygenetic trait with both hereditary and environmental components

Elbow screening represents an attempt to limit ED through selective breeding

Question 44

Clinical signs of elbow dysplasia

Answer 44

Lameness

Often shortened (‘choppy’) FL gait

Commonly bilateral, often asymmetric

Effusion (best detected on the lateral aspect of the joint between the lateral epicondyle and olecranon)

Pain +/- crepitus, reduced ROM

Question 45

Coronoid Disease/Medial fragmented coronoid process (mFCPD)

Answer 45

most common problem associated with elbow dysplasia

Labradors, GSDs, BMDs
6-14 months

Medial coronoid fragments due to sub-surface fissuring

Hard to see on X-ray - CT preferred

Arthroscopy is definitive

Untreated, will lead to DJD…but benefits of surgery not clear

Question 46

Osteochondrosis and Osteochondritis dissecans (OCD) of the medial humeral condyle

Answer 46

Usually the subchondral bone located immediately underneath the damaged area of cartilage is also affected.

Medial humeral condyle

Failure of endochondral ossification

Subsurface failure and cartilage lifts

Inflammation, pain, DJD

Surgical management - arthroscopic debridement +/- osteoarticular graft

Question 47

Ununited anconeal process (UAP)

Answer 47

anconeal process fails to fuse with the main ulna bone during the growth phase - normally would fuse by 5 months

Breeds commonly affected are German Shepard dogs, Great Danes, Basset Hound

Usually diagnosed based on radiographs, but the other conditions (FCP, OCD, and MCD) often cannot be distinguished

Surgery offers best prognosis
○ Reattachment if possible
○ Fragment removal if not

Question 48

Diagnosis of elbow dysplasia

Answer 48

Case history

Forelimb lameness that worsens after exercise

Acute or chronic.

Owners frequently complain that the dog is stiff in the morning or after rest.

There may be a coincidental history of trauma

Question 49

Clinical presentation/signs of elbow dysplasia

Answer 49

may show lameness of one or both front legs that worsens after exercise, stiffness and reluctance to exercise.

Often they stand with the front feet turned away from the body and the elbows tucked in.

Clinical signs generally start showing between 5 and 7 months

Question 50

Clinical examination of elbow dysplasia

Answer 50

Orthopaedic examination reveals pain at manipulation of the elbow and swelling of the joint is usually palpable.

Palpation is generally non-painful but manipulation through a full ROM shows reduced flexion and often pain on full extension or flexion of the joint.

In cases affected by severe osteoarthritis, a restricted range of movement of the joint is also generally noted.

Question 51

Radiography of elbow dysplasia

Answer 51

in very early cases no changes will be identified - repeat in 4-6 weeks if still showing signs

earliest sign - new bone on dorsal anconeal process (see on FLEXED mediolateral radiograph)

later arthritic changes seen on radial head, medial ulna and medial epicondyle of humerus

in some cases may see the lesion rather than just arthritic change e.g.:-
* flattening of medial humeral condyle on craniocaudal view if OC
* fragmentation/poor distinction of medial coronoid process of ulna in FCP
* Also subtrochlear sclerosis
ununited anconeal process usually obvious in dogs > 5mths

Question 52

CT of elbow dysplasia

Answer 52

Most reliable non surgical test

Can diagnose incomplete fragmentatio of the medial coronoid process

Question 53

Arthroscopy of elbow dysplasia

Answer 53

enables treatment via minimally invasive surgery to be performed at the same time if indicated

advantage of enabling direct visualisation of the cartilage surface

Usually used with CT

Question 54

Treatment of elbow dysplasia

Answer 54

Conservative - weight loss and exercise restriction

Rehabilitation - shockwave, laser, PRP

Nutraceuticals and chondroprotectants

NSAIDs

Surgery - quite controversial

Question 55

Coronoid disease

Answer 55

Medial fragmented coronoid process (mFCP)

Treatment can be conservative or surgical.

Coronoid disease will lead to osteoarthritis in all cases.

Question 56

Conservative treatment of coronoid disease (CD)

Answer 56

weight control,

exercise management,

hydrotherapy and physiotherapy,

nutraceuticals (joint supplements)

painkillers.

Question 57

Surgery for coronoid disease

Answer 57

arthroscopic removal of the fragments is generally performed and this leads to an improvement of the clinical signs in about 2 dogs out of 3.

Subtotal coronoidectomy.

Surgery not clearly better than conservative care.

Question 58

Treatment of osteochondrosis and osteochondritis dissecans

Answer 58

arthroscopic removal of the cartilage flap and possibly placement of a osteochondral graft.

This doesn’t improve clinical signs in a few cases.

Question 59

Osteostyxis for osteochondrosis

Answer 59

Hammer it

Bleeds and forms a clot

Clot turns into fibrocartilage

Works for small lesions but not large lesions

Question 60

Osteochondral transplant for elbow dysplasia

Answer 60

Osteochondral plug

Hit into subchondral bone

Fractures the base of that to create free piece of bone

Core out lesion

Put new cartilage back into hole

Natural auto-transplant

Question 61

Elbow joint replacement for elbow dysplasia

Answer 61

Replace whole articulation

Over time they start to loosen

Question 62

Elbow arthrodesis for elbow dysplasia

Answer 62

Plate holds the elbow stationary

End stage elbow disease

Primary goal is pain relief

Function can be quite variable

Alternative to amputation

Question 63

Elbow incongruity

Answer 63

Step between the radius and ulna

Short radius > short ulna

Hard to diagnose on x-ray, CT better

Surgical management usually involves ulnar osteotomy to allow the ulna to ‘find a new position’

Question 64

Treatment of ununited anconeal process (UAP)

Answer 64

In young dogs (under 8 months of age) can be reattached to the ulna with a screw

To stimulate fusion and counteract the abnormal forces acting on this bony process, an ulna osteotomy or ostectomy is generally also mae

Older dogs can be treated with conservative management or removal of the anconeal process

Question 65

Osteoarthritis in elbow dysplasia

Answer 65

A consequence of all cases of elbow dysplasia

weight management and exercise modification are the best ways to influence outcome

Question 66

Prognosis of elbow dysplasia

Answer 66

no curative treatment

prognosis is guarded for dogs in regards to the development of osteoarthritis.

However, clinical improvement is seen in many cases after the various treatment options, and many dogs with elbow dysplasia can still have an excellent or good quality of life.

A small group of patients, however, may not respond to any treatment and for those salvage procedures, like a total elbow replacement, may be considered.