Ch 50 the shoulder

Question 1

anatomy

Answer 1

two-thirds of the motion the shoulder joint, and one-third the scapulothoracic synsarcosis

the tendon of origin of the biceps brachii muscle passes through the intertubercular groove, held in place by the transverse humeral retinaculum.
The joint capsule blends with tendons > “rotator cuff” muscles in human beings:
- medially: include the subscapularis and coracobrachialis
- laterlly: supraspinatus, infraspinatus, and teres minor

lateral and medial glenohumeral (collateral) ligament

Question 2

At what age do the glenoid and proximal humeral physes fuse?

Answer 2

Glenoid - by 6mo
Proximal humerus - by 12mo

Question 3

What is the ratio of glenoid to humeral head ratio?

Answer 3

1:2.5

the joint is moderately congruent

Question 4

What are the three zones of the labrum?

Answer 4

Transitional zone (collagen fibers in a fishnet-like pattern)
Circular fiber zone
Meniscal fold

The labrum is highly vascularised along the free margin and is loosely attached to the glenoid

Question 5

How thick is the hyaline cartilage of the shoulder joint?

Answer 5

approx 1mm in 20-25kg dogs

Question 6

What shape are the collateral ligaments of the shoulder?

Answer 6

Medial glenohumeral ligament is Y-shaped
Lateral glenohumeral ligament is a thick band

Question 7

What structure function to keep the tendon of the origin of the biceps brachii within the intertubercular groove?

Answer 7

Transverse humeral retinaculum

Question 8

What are the normal flexion and extension angles of the shoulder in the dog and cat?

Answer 8

Dog
- extension 165
- flexion 57

Cat
- extension 164
- flexion 32

Question 9

List the passive mechanisms of shoulder stability

Answer 9

Limited joint volume
Adhesion/cohesion mechanism
Concavity compression
Capsuloligamentous restraints (glenohumeral ligaments, joint capsule, labrum, and biceps brachii tendon origin)

Question 10

What are the main active stabilisers of the shoulder?

Answer 10

Supraspinatus
Infraspinatus
Teres minor
Subscapularis

And to a lesser extent:
- Biceps brachii
- Long head of the triceps
- Deltoideus
- Teres major

respond to stresses created by locomotion and weight bearing. Active mechanisms also improve joint stability and glenohumeral balance by enhancing glenoid concavity compression.

Question 11

What type of mechanoreceptors are within the collateral ligaments?
What is their function?

Answer 11

Type I, II and III mechanoreceptors
Type I (Ruffini) are the most common
Allow ligaments to work as sensory structures to actively contribute to shoulder stability via reflex arcs with the associated musculature

Question 12

immobilization of shoulder joint is entirely reversible, even when the period of immobilization is prolonged.

Question 13

diagnosis

Answer 13

phyiscal exam
begin with a thorough history of the lameness, including signalment
walk, palpation of the shoulder joint and associated musculature, joint range of motion and stability, and pain
neuro: CP deficits, atrophy, neck pain, reduced withdrawal
goniometry

diagnostic intra-articular anesthesia….?

arthrocentesis
valuable information for identifying immune-mediated and septic disease,

Rads
radiographic changes, even mild ones, are strong indicators of intra-articular disease. Osteoarthritis is rarely a primary disease of the shoulder joint
fractures, OCD, incomplete ossification of the caudal glenoid, chondrocalcinosis, glenoid dysplasia, and traumatic luxations
Stress (abduction) views may assist in the diagnosis of instability of the medial side of the shoulder joint, but the highly mobile nature of the normal shoulder joint warrants caution

Arthrography
outlining soft tissue structures and abnormalities of the shoulder joint, such as the tendon of origin of the biceps brachii muscle, osteochondritis dissecans flaps, medial joint stabilizers, intra-articular loose bodies, synovial neoplasms,

CT/MRI
CT and CT arthrography allow visualization of the peri- and intra-articular soft tissue structures except for the teres minor muscle tendon and coracobrachialis muscle

MRI allows identification of both intra-articular and extra-articular structures of the joint.

ultrasound
examination of the tendon also facilitates safe and efficient aspiration of surrounding synovial fluid and therapeutic injections.
The tendons of the supraspinatus, infraspinatus, and teres minor muscles and the caudal aspect of the humeral head can also be reliably imaged ultrasonographically.
limitation medial structures

Question 14

chondrocyte toxicity

documented of many commonly used local anesthetics in a wide range of species.

One publication suggested that a single intra-articular administration of bupivacaine, because of the drug’s rapid dilution and drop in intra-articular concentration, did not pose a significant risk for chondrocyte damage.

Several in vitro studies document protective effects of vitamin C, N-acetylcysteine, and hyaluronan on chondrocytes prior to exposure to local anesthetics.

Until more is definitively known about the effects of local anesthetics on canine and feline chondrocytes and the clinical utility and effectiveness of protective drugs, intra-articular instillation of local anesthetics should be used as a single administration, if at all

Question 15

What is the optimum concentration of iodine for arthrography when VT angiography is performed?

Answer 15

60mg/ml

Question 16

What percentage of shoulder pathology is extra-articular and therefore would be missed on arthroscopy?

Answer 16

15%

Question 17

mineralization within the tendon

Answer 17

mineralization within the tendon of origin of the biceps brachii muscle and tendon of the supraspinatus muscle

study
unilateral or bilateral thoracic limb lameness revealed that almost 40% of dogs identified by CT scan as having mineralization of periarticular soft tissue structures of the shoulder were not lame on the limb with periarticular mineralization.

Almost 90% of dogs with thoracic limb lameness and concurrent mineralization of periarticular soft tissue structures of the shoulder either had other documented shoulder pathology or had elbow disease.

Question 18

What is the recommended angle for excision arthroplasty of the glenoid?

Answer 18

excision arthroplasty is to form a “false” or fibrous joint between the humeral head and the scapular neck

• Distolateral to proximomedial osteotomy of the scapular neck
• Being careful to protect the suprascapular nerve

excision of humerus head not necessary

Question 19

What is the outcome of excisional arthroplasty?

Answer 19

Good-to-excellent in small dogs
Unknown in large breeds

Question 20

What angle of shoulder is aimed for in arthrodesis?
What landmark should be used for the rotation alignment?

Answer 20

105-110 degrees

The greater tubercle should be positioned craniodistal to the acromion and slightly medial in the sagittal plane

plate should extend from the distal half of the scapula to the proximal half of the humerus (typically at least four or five screws in each bone). The plate is contoured

In small dogs > large transarticular screw or diverging Kirschner wires
clinical outcomes are generally better when plates and screws are used for all sizes of dogs and cats.

Principles of arthrodesis (removal of articular cartilage and rigid fixation of the joint at a functional angle) are followed.

cancellous graft augmentation may not be as critical in the shoulder joint as in other joints because of the normally high cancellous bone content in the humeral head

Question 21

craniolateral approach.
The insertion of the trapezius muscle and the origin of the omotransversarius muscle are elevated from the cranial edge of the scapular spine as needed.

The incision is continued distally along the cranial border of the acromial head of the deltoideus muscle. The omobrachial vein (and cephalic vein, if necessary) is divided, and the incision follows the lateral aspect of the brachiocephalicus muscle to its insertion. The insertion of the superficial pectoral muscle is incised and the muscle elevated and retracted cranially.

Although osteotomies can be performed, tenotomy of deltoideus and supraspinatus tendons may result in fewer complications due to osteotomy nonunion

Answer 21

Elevation of the supraspinatus muscle, uprascapular nerve is identified, The lateral collateral ligament is transected and the joint capsule incised to allow luxation of the humeral head from the glenoid fossa.

A motorized burr is used to remove the articular cartilage from the surfaces of the humeral head and the glenoid fossa. stectomy of the distal tip of the glenoid and corresponding humeral head may be required to create an acceptable degree of contact between

thin bone of the scapula makes screw pull-out and construct failure more likely. Locking plate technology may therefore be preferred, however consider compression

Question 22

What is the reported outcome after shoulder arthrodesis?

Answer 22

Good-to-excellent
Normal or near-normal gait in 12 weeks

Question 23

What is the most common location of shoulder OCD?
How often is this disease bilateral?

Answer 23

caudocentral or caudomedial aspect of the humeral head, usually opposite the caudoventral rim of the glenoid
27-68% bilateral

Question 24

What percentage of OCD cases will have a nonmineralised cartilage flap trapped within the tendon sheath of the biceps?

Answer 24

Approx 10%

Question 25

What are the approach options of debridement of a shoulder OCD flap?

Answer 25

Caudal
- requires assistant for retraction
- results in less loss of RoM and improve weight bearing in first month

Caudolateral interdeltoideus approach
- Craniodorsal retraction of infraspinatus and teres minor
- Better protection og caudal circumflex humeral artery and axillary nerve

Craniolateral
- Included tenotomy of infraspinatus tendon
- Greater exposure of caudal aspect of humeral head but limits access to caudal joint pouch

modified cheli
articular access between the supraspinatus muscle and the infraspinatus tendon. Cheli modification > forced hyperflexion.
caudal displacement of the acromial deltoid and infraspinatus muscles, further modified by Vezzoni to limited open approach without humeral head luxation

Question 26

a caudolateral approach
with craniodorsal retraction of the teres minor muscle (no tenotomy) has been shown to result in increased joint extension and range-of-motion compared with a craniolateral approach with tenotomy of the infraspinatus muscle, but there was less exposure to the articular surface compared with a craniolateral approach

Question 27

What is glenoid dysplasia?
What breeds are predisposed?
What does it cause?
What is the treatment?

Answer 27

Glenoid dysplasia is hypoplasia or aplasia of the glenoid resulting in grossly abnormal articulation
Toy breeds (Toy and Min poodle, Chihuahua, Pom, Sheltieetc)
Results in medial luxation of the shoulder
Tx: Arthrodesis or excision arthroplasty with an acceptable return to function

generally diagnosed in dogs between 3 and 10 months

Question 28

What is multiple epiphyseal dysplasia?
What is the treatment?

Answer 28

A rare defect in the ossification of the epiphyses of long bones, vertebrae, cuboidal bones and apophyses
Severe lameness, resembles bony changes seen with congenital hypothyroidism
Tx: euthanasia

Question 29

In what breed has focal humeral head dysplasia been reported?

Answer 29

Boerboel (Arthrodesis)

Question 30

What is the radiographic hallmark of HOD?

Answer 30

“Double physis” - irregular radiolucent line in the metaphysis, parallel to and seperate from the physis

Question 31

What is chondrocalcinosis?
What breeds are overrepresented?
What gross lesions are seen?
Is it clinically significant?

Answer 31

• Chondrocalcinosis is deposition of hydroxyapatite in the articular cratilage, “pseudogout”
• Overrepresented in the Greyhound and GSD
• Gross lesions: small pits in cartilage surface, scarring, scoring and cracking, often unilateral
• Often found incidentally at necropsy, clinical significance unknown

Question 32

What is this disease?
Is it clinically significant?

Answer 32

Incomplete ossification of the caudal glenoid
- Often asymptomatic but can be a cause of lameness if mobile
- Arthroscopy to comfirm if mobile and can remove the fragment

Question 33

Biceps Brachii Tendinopathy

exact pathophysiologic mechanisms responsible remain unknown.

Answer 33

primary or secondary

Primary
inflammation of the tendon of origin dt overuse or chronic repetitive injury.
area of relative hypovascularity may predispose to mechanical failure (fraying or rupture)

Secondary
in response to other intra-articular disease or trauma to other tendons of shoulder

Question 34

biceps tendinopathy
CS

Answer 34

middle-aged to older, medium- to large-breed dogs.

chronic intermittent or progressive weight-bearing thoracic limb lameness, which becomes worse with exercise

Question 35

Lists tests which can be done to test for biceps tendinopathy

true prevalence is unknown

Answer 35

• Biceps tendon test
  direct digital pressure against the tendon of origin while the shoulder joint is flexed and the elbow extended
• Drawer test
  Places direct pressure against the tendon and associated sheath (doe not test for tearing/rupture)
  humerus is translated cranially
• Biceps retraction test
  Grasping the tendon of insertion at cranial elbow and pulling caudally whilst weight-bearing

All tests are assessing for a pain response

Question 36

biceps tendinopathy
DX

pro’s of u/s?

Answer 36

Rads
standard orthogonal
flexed craniodistal-cranioproximal (skyline) (view intertubercular groove, mineralization of the tendon + distinguishing mineralization in the tendon of the supraspinatus muscle

Contrast arthrography

ultrasonographic
more sensitive, earlier diagnostic tool, however diseased BT can look normal
ID changes within tendon
sonolucent line around the tendon; hypoechoic tendon with fiber disruption; proliferative synovium; irregularities of bicipital groove

MRI
evaluation of all other soft tissue structures of the shoulder joint
i.e. Concurrent displacement of the tendon
arthrography > tendon avulsions and tears, impingement of the suprapinatus tendon on biceps

Question 37

biceps tendinopathy
medical Tx

Answer 37

1. long-acting CCS
   - methylprednisolone acetate (10 to 40 mg), strict cage rest and a gradual return to activity
   - intratendon injection vs intraarticular: question the need, anecdotally intra-articular
   associated with tendon weakening and rupture in human and rabbit
   - systemic effects of long-acting steroids?
   - potenital effects on articular tissues to use triamcinolone (5 mg per joint) > no published reports
   - need for prolonged (4 to 6 weeks) strict confinement
   - Concurrent physical rehabilitation therapy
2. nonsteroidal antiinflammatory drugs,rest, physio
3. prp, stem cells, no objective studies have been published

corticosteroids reduce the inflammation

Question 38

What are the surgical options for biceps tendinopathy?

Answer 38

1. Tenodesis
   to the proximal portion of the humerus through a cranial arthrotomy
   extrapolated from the human medical literature.
   Good long-term outcomes generally reported in dogs
   Arthroscopically assisted tenodesis decreases the incidence and severity of complications
   return 12 to 18 weeks after surgery
2. Tenotomy
   open or arthroscopically
   using hooded arthroscope knife or bipolar
   tendon provide passive restraint to the shoulder joint > Further studies needed to asses if joint stability is effected

arthroscopy
lateral shoulder joint portal
a craniolateral instrument portal
tendon is released from its origin on the supraglenoid tubercle
joint can be slowly flexed, resulting in tension on the tendon

rehabilitation will maximize the speed and extent of recovery

Question 39

What breeds are predisposed to medial displacement of the biceps tendon of origin?
What are the surgial options?

Rupture of transverse humeral retinaculum - cause unknown.

Answer 39

Greyhounds, Afghan hounds, GSD, Border Collies

Primary reconstruction of the transverse humeral retinaculum and/or augmentation with screws and PDS or staples and polydiaxonone mesh

Prognosis excellent

displace medially from groove when joint extended and supinated or flexd

Question 40

supination (palm facing upwards), and pronation (palm facing downwards).

Question 41

Rupture of the Tendon of Origin of the Biceps Brachii Muscle

Answer 41

direct laceration, avulsion or midsubstance tear
+/- traumatic shoulder joint luxation.

pain, swelling, joint instability, and lameness > acute vs chronic

Ultrasonographic: inhomogeneous hyperechoic area in tendon’s origin on the supraglenoid tubercle
Arthroscopic examination

Tx: Tenodesis

Question 42

What breeds are predisponsed to calcification of the biceps tendon of origin?

pathogenesis

Answer 42

Labs and Rottweilers

pathogenesis of dystrophic calcification unknown.
tendon trauma results in a disturbance of blood supply, leading to hypoxia.
Hypoxia may trigger remodeling into fibrocartilage

radiographic abnormality: mineral opacity in the cranial aspect of the shoulder ddx supraspinatus

Tx: rest and administration of nonsteroidal antiinflammatory
Tenodesis

Question 43

supraspinatus tendinopathy

Rottweilers and Labrador Retrievers predisposed

Answer 43

dystrophic calcification vs incidental finding
pathogenesis is unknown - area of hypovascularity in the tendon of the supraspinatus muscle

Dx: Signalment, history, and exam similar to biceps brachii
- presence of mineralization bilaterally, clinical signs may be unilateral
- skyline view, ultrasonography, CT, or MRI may be necessary to confirm the diagnosis and differentiate calcification
- Mineralization in the medial aspect adjacent to biceps tendon may be clinically significant > impingement or displacement of the tendon (accurately identified by MRI)

Question 44

What is the surgical treatment of supraspinatus tendinopathy?

Answer 44

Excision of calcified tissue (controversial if medical vs surgical treatment is best)

rest and administration of nsaid

Sx: variable success rates have been reported, Hypodermic needles and C-arm fluoroscopy can be used intraoperatively

Rehabilitation exercises should be performed following surgery

Question 45

What is the most common direction of shoulder subluxation?

Answer 45

Medial instability (approx 80%)

Question 46

Instability or subluxation of the shoulder joint

both large- and small-breed dogs

Answer 46

small dogs
the condition may occur as a congenital
3 and 10 months of age
usually unilateral.
Breed predispositions include Toy and Miniature Poodle, Chihuahua, Pomeranian, Pekingese, Miniature Pinscher, Lhasa Apso, and CKCS
may hold the affected limb with the elbow joint flexed and adducted and with the distal part of the limb abducted.
Abnormal spatial differences between the acromion and the greater tubercle are appreciated with palpation

large dogs
the condition is usually considered a sign of repetitive microtrauma
secondary osteoarthritis are common

Question 47

pathophysiology of shoulder joint instability

Answer 47

not been fully determined > extrapolation from the human literature

1. loss of concavity compression,
   > ball in the concavity have greater resistance to translational forces
   > depth of the concavity through glenoid labrum or ligaments
   > magnitude of the compressive force provided by periarticular muscles.
2. disruption of glenohumeral balance
   > net joint reaction force passes through the center of the joint, provided by mucles and capsuloligamentous restraints

Question 48

What is the normal shoulder abduction angle

Answer 48

Approx 30 degrees (vs 50 with instability)

Question 49

how dx instability?

Answer 49

hx: chronic lameness, which is often subtle and intermittent
nonresponsive to nonsteroidal
atrophy of the shoulder muscles

ex: during sedated examination because pain and apprehension
abduction angle of the shoulder > standing angle. The scapula is stabilized, the humerus is abducted, and the angle formed by the shaft of the humerus and the spine of the scapula
Gray et al: variability between individual shoulders, weak to identify subtle changes
one study used goniometry: 50 degrees in clinically affected dogs

RADS: Subtle degenerative changes, varus and valgus stressed views may identify excessive joint capsule and collateral ligament laxity (caution advised)
Arthroscopic: valuable for identifying medial instability, extent and type of degenerative changes (erosion of cartilage of caudal humeral head or medial ridge of glenoid; tearing of the medial glenohumeral ligament; and synovitis)
evaluation is very subjective and not reliable

Question 50

What treatment options are available for stabilisation of the shoulder joint? (6)

poorly responsive to conservative therapy

Answer 50

1. Transposition of the tendon of origin of the biceps or supraspinatus (84.5% good to excellent outcome)
2. Augmentation of medial collateral with suture (medial aspect of the scapular neck and humeral head > not alter joint anatomy, and more biomechanical)
3. Imbrication of tendon of subscapularis muscle via craniomedial approach for mild degrees of instability
4. Radiofrequency induced thermal modification (RITM) > Thermal energy is applied to capsule, shrinking the collagen bundles, only if if the tendon of origin of the biceps brachii muscle, articular cartilage, and lateral compartment were normal, NOT effective in mod-severe instability/tear
5. Excision arthroplasty
6. Arthrodesis (85.7% good to excellent) if OA or prior Sx fail

Transposition techniques result in altered biomechanics, incongruency and OA.
Placement of heavy synthetic suture preferred method in a V-shaped (at attachments of the cr.and ca. medial glenohumeral lig.) with screw and washer bone tunnels or anchours
> motion with good congruency, mobility, and less alteration of normal anatomy in 9 of 10 dog

Question 51

Postoperative Management and Outcomes shoulder instability

Answer 51

post-op
- allow adequate time for scar tissue to functionally stabilize the joint. Maintenance of the limb in a Velpeau sling for 6 weeks (bandage complications and joint stiffness)
- gradual return to function and rehabilitation exercises are recommended for 4 to 6 weeks (to allow properly remodel the collagen scar tissue over time)

outcome
- Thermal damage to glenohumeral ligament during RITM may temporarily injure the proprioceptive function of the ligament
- Tendon transposition: 84.5% good to excellent outcome, no long-term studies
- augmentation: Clinically, functional outcomes are better
- Arthrodesis reportedly yielded good to excellent results in 85.7% of 14 dogs
- veterinary literature, limited information is available: Functional outcomes RITM in dogs are somewhat difficult to truly know. numerous potential pitfalls have been acknowledged in the human and veterinary literature. consistently, uniformly, and without deep tissue damage or excessive heating of the collagen, urthermore, the collagen tends to stretch back to its original length with time and use.

Question 52

laterial instablity

Answer 52

Complete tears of the lateral, All dogs had incomplete tears of the medial glenohumeral ligament.

Tx: intra-articular 40 mg of methylprednisolone + rested for 4 to 6 weeks.

Two of three dogs returned to normal function as reported by the owner; the third dog underwent surgery to reconstruct/augment the lateral glenohumeral ligamen

Question 53

Traumatic Luxation
most common direction? in large breed?

Answer 53

most frequently in a medial direction
large-breed dogs often results in lateral luxation

Question 54

shoulder luxation - dx

Answer 54

dx
identical to the presentation of congenital medial luxations
Mediolateral and craniocaudal survey radiographic views are usually sufficient to document the luxation

Question 55

shoulder luxarion conservative options?

Answer 55

tx
Conservative treatment of traumatic medial luxation of the shoulder joint is usually successful if the luxation is reduced and stabilized with a Velpeau sling soon after injury
Lateral luxation, if the injury is recent and the joint is stable following reduction, can also be treated by closed reduction, but the thoracic limb should be placed in a neutral sling or spica splint, avoiding adduction of the shoulder
limited information is available regarding the management of cranial and caudal luxations
ehabilitation exercises are recommended for 2 to 6 wks

Question 56

shoulder luxation Sx options?

Answer 56

Sx
If closed reduction cannot be accomplished, or if the joint is grossly unstable following closed reduction of luxation, surgical reconstruction or augmentation of the glenohumeral ligament(s) and joint capsule is recommended.
transposition of the tendon > joint incongruency and degenerative joint disease
modified Campbell prosthetic suture (heavy suture passed through transverse holes in the humeral head and scapular neck to create or augment glenohumeral ligaments
Treatment of severe shoulder joint derangement by temporary transarticular bridging with a locking bone plate and screw
Salvage procedures such as arthrodesis and excision arthroplasty
prognosis: generally good.
glenoid excision or arthrodesis should be expected to have some minor degree of gait alteration and limited range

Question 57

What is the range of grades of muscle strain injury?
what animals?
Tx?
which muscles? (7)

difficult to dx, Ultrasonography or MRI to localize

Answer 57

Grade 1 = minimal tearing of individual muscle fibres

up to Grade 4 = Complete muscle rupture requiring debridement and repair

Tx:
grade 1 - 3: ice pack, followed by warm compresses, compressive wraps, nsaid + analgesics, relaxants, rest, and physical rehabilitation

grade 4 > surgical debridement and repair of the muscle may be appropriate

usually occur in mature athletic dogs and result from overstretching or overuse

near the musculotendinous junction

muscle is strained to 80% of failure, the strength of muscle contraction is decreased by 30% immediately after injury, by 50% after 24 hours, and by 25% after 48 hours, and recovering to 90% of original function after 1 week

susceptible mm: biceps, triceps, pectoral, serratus ventralis, rhomboideus, extensor carpi radialis, flexor carpi ulnaris

Question 58

What are some clinical features of teres minor myopathy?
Treatment of choice?

Answer 58

Prominent pain with reduced shoulder flexion
Tx: excision of enture muscle, excellent prognosis

Ultrasonography or MRI can be used to localize the lesion

Question 59

What breeds are predisposed to infraspinatus contracture?
What is meant by a biphasic history?
What are some characteristic gait features?
Tx?

everely damaged muscle has little regenerative ability,

Answer 59

Brittany spaniel, Pointers, Labs
Biphasic
- Acute painful pain, swelling and lameness
- Chronic, static, nonpainful gait abnormality with mm atropht/prominent scapular spine

Gait
- elbow adduction, shoulder abduction
- external rotation of antebrachium
- circumdution of limb with carpal flip

ultrasonographic examination reveals hyperechoic changes in the muscle +/- MRI

Tx: Tenotomy of the tendon through a lateral approach, with release of adjacent capsular adhesions

Contracture > fibrous connective tissue replacement of muscle secondary to degenerative changes, dt low-grade repetitive trauma from vigorous activity
+/- compartment syndrome

Question 60

List the treatment option of villonodular synovitis

Answer 60

Synovectomy
Radiation therapy
anti-TNF-a administration
excision arthroplasty or arthrodesis

Question 61

What is the disease seen in the radiograph?
What are the treatment options?

Answer 61

Synovial chondrometaplasia
- a proliferative disorder of undiffernetiated stem cells. Fibroblast-like cells are transformed into chondroblastic cells under the influence of the extracellular chondroid matrix material

Treatment
- Good outcome with debridement of nodules, loos body removal and synovial stripping
- Excision arthroplasty or arthrodesis

Question 62

Infraspinatus Bursal Ossification

Answer 62

Infraspinatus bursal ossification has been reported in Labrador Retrievers

Radiographic changes include single or multiple mineralizations (osteochondromatosis) within the infraspinatus bursa that are best observed in the craniocaudal view. These mineralizations may not be clinically significant if pain cannot be elicited when pressure is applied directly over the tendon.

Treatment with rest and nonsteroidal antiinflammatory drugs or intra-articular long-acting corticosteroids

Surgical excision of loose bodies, the infraspinatus bursa, and a portion of the tendon of the infraspinatus muscle

Question 63

Ectopic or heterotopic ossification of soft tissues (other than synovium, supraspinatus muscle, tendon of origin of the biceps brachii muscle, and infraspinatus bursa) can occur in the canine shoulder.

Question 64

Management of medial luxation of the shoulder joint in toy-breed dogs using an antiluxation pin placed lateral to the supraspinatus muscle tendon: 20 limbs (2017–2022)
Takeshi Aikawa 2024

Answer 64

retrospective study
18 client-owned toy-breed dogs (20 treated limbs).
CLINICAL PRESENTATION
Toy-breed dogs treated with the antiluxation pin lateral to the supraspinatus muscle tendon
Reluxation occurred in 3 limbs
final follow-up (median, 18.5 months
gait assesment only, use of force plates and kinematic studies are desirable

prevented the recurrence of and maintained a good long-term function

Question 65

Synthesis of surgeon and rehabilitation therapist treatment methods of bicipital tenosynovitis in dogs allows
development of an initial consensus therapeutic protocol
Lane 2024

Answer 65

limited canine research available, relevant human research, and what is known about tissue repair,formulate the following recommendations:
* No surgery if BT is healthy or if the amount of fiber tearing is ≤ 20%.
* BT is 75% torn, surgery approach. Conservative guarded prognosis.
* tears between 20% and 75%, a case-by-case decision, ensuring best communication about advantages and disadvantages with the owners is likely the best approach.
* NSAIDs only short-term pain control, protracted use may delay healing. NSAIDs are not indicated in chronic cases.
* Intra-articular corticosteroids are not an appropriate long-term conservative treatment and are contraindicated
* Intratendinous corticosteroid injections must not be performed. If the end goal is tendon necrosis, a biceps tenotomy should be considered instead, using the least invasive approach available.
* PRP might be useful > currently a lack of evidence in the published literature
* Cage rest is discouraged
* Consider multimodal Tx: physio with activity restriction that returns to normal in a staged manner over several months.
* Modalities such as ESWT, regenerative medicine, and photobiomodulation should be considered.
* At this time, there is insufficient evidence to recommend therapeutic ultrasound, PEMF, or acupuncture.

Question 66

Pilot study of the ultrasonographic examination of the intact
and transectedmedial glenohumeral ligament in dogs
Gemignani 2023

Answer 66

the medial glenohumeral ligament could be identified with a medial ultrasonographic approach of the shoulder and a wider articular space can be a sign of a medial shoulder joint instability.

Further studies are needed to confirm these preliminary findings in living dogs,
with and without shoulder instability.

Question 67

Functional outcomes of dogs undergoing shoulder arthrodesis with 2 locking compression plates
Phipps 2023

satisfactory standing angle (110 to 120 degrees)

Answer 67

Retrospective case series.
Animals: Twelve client owned dogs undergoing shoulder arthrodesis using
2 LCPs as the principal method of fixation.
clinical assessment, (LOAD) scoring, force plate analysis, at least 6 months follow up.

ALL cases > satisfactory progression of arthrodesis at 6 weeks postoperatively, defined by loss of the
radiolucent line previously present

Minor complications > 2/12 dogs, neither requiring surgical revision
11/12 > full functional recovery
complication rate favorable compared to previously published
> 64.3% (9/14) occurring in 50% of
dogs (7/14) and a 14.3% (2/14) catastrophic complication rate resulting in amputation or euthanasia
5/12 dogs, mean of 31.9% of their bodyweight on the operated limb

good outcomes in our clinical setting

shoulder joint exposed through transection of the insertion of the acromial head of the deltoideus, allowing identification of the tendon of insertion of the infraspinatus and teres minor on the proximolateral humerus. Both tendons were transected
sterile goniometer was used to evaluate and adjust the angle of arthrodesis

As with our study, a variety of other implants
including screws and variable numbered K wires suggesting that double locking plates do carry a biomechanical advantage, but futher studies required

Question 68

As suggested in previous studies, use of bone graft was deemed elective and clinician dependent in our study and was therefore used in only 50% of cases > no difference in healing outcome

Fixed angle constructs created with locking plates and locking screws shown to produce stronger methods of fixation compared to conventional, where prolonged construct stability is required or contouring is not possible
Locked implants provide both angular and
axial construct stability

Answer 68

A recent case report
custom manufactured 3-d cutting and reduction guides for shoulder arthrodesis allowed accurate precontouring
of locking plates onto the planned glenohumeral arthrodesis

resulted in an excellent outcome and
reduced intraoperative time.

Question 69

Ex vivo evaluation of arthroscopically assisted shoulder
stabilization in dogs using an intra-articular aiming device
Rocheleau 2023

Answer 69

Ex-vivo Study
Methods: Specimens were randomly divided into 2 groups with 10 shoulders each.
arthroscopically assisted stabilization with either bone anchors or suture-toggle constructs.
Abduction angles restored to normal in the anchor group, but 2 smaller than normal in the suture-toggle group
Placement of anchors were not feasible in 3 and mild violations of the articular surfaces were detected in 3 specimens overall > suture-toggle technique may be superior

An IAD may facilitate arthroscopic shoulder stabilization in dogs. Further studies are warranted to evaluate safety and efficacy in a
clinical setting

a higher insertion angle may result in a lower
probability of a violation of the articular surface
demonstrated by multiple mechanical
studies that the insertion angle is important
with respect to pull out

neurovascular structures in the region > not be entrapped by the suture tape as it courses over medial side

raise the question of tensioning the repair - surgeon subjective

Further study is indicated to evaluate the mechanical properties of these repairs as well as in vivo performance > but a true direct comparison is not possible

Question 70

Preoperative and postoperative abduction angles were reported as outcome measures by O’Donell et al.

arthroscopic pre- and post-transection abduction anglesmore recently reported by Jones et al and Livet et al

These more recent studies have called into question the clinical validity of shoulder abduction angles.

Answer 70

Penelas et al reported an operative
time of 48 ± 12 min, compared with 30-45 min in our anchor group; however they also incorporated an imbrication of the subscapularis tendon into their repair, and the entire repair was carried out arthroscopically.

Question 71

A Modification of the Cheli Craniolateral Approach for Minimally Invasive Treatment of Osteochondritis Dissecans of the Shoulder in Dogs: Description of the Technique and Outcome in 164 Cases
Vezzoni 2021

Answer 71

164 shoulders in 141 dogs treated with modified craniolateral approach
In all cases, approach allowed visibility and adequate exposure of the caudal humeral head surface. Radiographic and clinical follow-up evaluations were available in (75%)

follow-up examination 2 to 3 months> 8 dogs (6.5%) had persistent mild lameness. In five, clinical signs disappeared

> 1 year after surgery, in 16 cases (9.7%) and none were lame on gait evaluation

When free flaps are seen on rads > an arthroscopic approach should be considered.
2 dogs with intraoperative bleeding, the surgical approach was more proximal than desired > omobrachial vein injury.

moderately challenging, minimally invasive, efficient and inexpensive alternative

joint cannot be completely evaluated for
other diseases. The majority of dogs with OCD could be successfully treated.

very large or deep lesions, Cheli approach can be used to allow OATS/synthetic resurfacing implant.

Question 72

Long-term outcome of dogs treated by surgical debridement of proximal humeral osteochondrosis
Zann 2022

a cross-sectional study is a type of observational study that analyzes data from a population, or a representative subset, at a specific point in time—that is, cross-sectional data

Answer 72

Cross-sectional study.
20 dogs (n = 26 shoulders).
surgical debridement of proximal humeral OC lesions >12 months prior
Orthopedic examination, kinetic gait analysis,
radiographs, (CT), and arthroscopy performed.
needle arthroscopy may be equivalent to conventional arthroscopy for the diagnosis of some shoulder pathology

no differences in peak vertical force and vertical impulse between affected and unaffected limbs. 4.4% decrease in load distributed to the operated limb

OA + muscle atrophy > all shoulders treated for OC lesions.
Arthroscopically > all lesions patchy, incomplete cartilaginous infilling.
No more than 60% infilling
mechanisms that may explain this finding.
1. Studies in horses> fibrocartilage
formed after subchondral curettage is mechanically inferior
2. Studies experimentally created cartilage defects in dog demonstrated decreased bonding of natural reparative fibrocartilage to the subchondral bed

most dogs exhibiting subtle lameness on the subjective gait examination. Despite this, owner-perceived mobility was satisfactory

The findings underscore the need for further scientific investigation into the most effective management of proximal humeral OC.
Surgical debridement > not restore
the articular surface or prevent OA but appears clinically beneficial in the majority of dogs.

Question 73

Voss et al. has demonstrated that compared with a walking gait, trotting increased the sensitivity accuracy of low-grade lameness detection in dogs

Answer 73

The most effective means of subchondral bone stimulation remains unexplored in the veterinary literature.
Curettage:
leads to local destruction of chondrocytes and inadvertent removal of healthy tissue
This can lead to delayed healing
and a poorer quality of fibrocartilage infilling

Microfracture:
result in increased fibrocartilage
infilling volume with a greater percentage of type II collagen content

histologic studies:
demonstrated that secondary fibrocartilage stimulated by surgical debridement or forage does not have the same mechanical or structural properties of healthy hyaline
cartilage

Question 74

Inverted V-shaped extracapsular stabilisation technique and arthroscopic findings in six dogs with medial shoulder instability
Hammer and Grand 2021

Answer 74

retrospective case series
report arthroscopic findings and clinical outcomes of dogs treated with an inverted V- stabilisation technique without additional external coaptation

screws and spiked washers as anchor points for the coated polyester prosthetic ligament

Implant loosening > 2/6 dogs
no revision surgery was performed.
Function at the time of last clinical follow-up (median, 28 months, range 18 to 33 months) was full in 4/6 and acceptable in 2/6 dogs

Despite the limited number of cases, the present study suggests that additional postoperative external coaptation may not be necessary
Major limitations of this study included the small number of cases, its retrospective design, the lack of a control group

The suture material must maintain joint stability until the soft tissues have healed with maturation of scar tissues.

Question 75

Fitch et al. 2001, O’Donnell et al. 2017 > documented clinical outcomes of prosthetic reconstruction used for the treatment of MSI with successful outcomes in 90 to 100% of cases
Fitch et al. (2001) > V-shaped prosthetic repair
O’Donnell et al. (2017) described a single
humeral tunnel method using bone tunnels for suture anchorage

Question 76

Effects of shoulder distraction on canine shoulder arthroscopy
Aoki 2021

Answer 76

To evaluate the use of the Leipzig distractor during canine shoulder arthroscopy.
Study design: Experimental, ex vivo.
Sample population: Paired shoulder joints from 15 large cadavers.

Clinical significance: clinical studies are required to evaluate the effect of the distraction device on pathologic articular conditionsand intraoperative manipulation, the use of a shoulder distraction device
might improve the outcomes of shoulder arthroscopy by decreasing IACI and
arthroscopy time.

Question 77

Measurement of Shoulder Abduction Angles in Dogs: An Ex Vivo Study of Accuracy and
Repeatability
Jones (pozzi) 2019

Answer 77

accuracy and repeatability of shoulder abduction test and to assess the effect of transection of the medial shoulder support structures in cadavers.
abduction angle was measured by three separate observers (extended and at a neutral angle) + fluoroscopic images

All three observers had differentmeasured abduction angles when compared
with fluoroscopy (p < 0.01); however, the experienced surgeon had an error of only
2.9°.
Inter-observer repeatability was poor
Intra-observer repeatability excellent.
neutral standing angle, and transection of support structures caused an average increase in abduction by 8.2° and 4.4° respectively.
Shoulder flexion angle can significantly affect measured abduction angles.

shoulder abduction test is not as accurate as the fluoroscopic measurement >end-point may be challenging to discern clinically
BUT > may be accurate enough for detecting
clinically relevant hyperabduction angles.

Transection of the medial supporting structures of the shoulder joint resulted in only a limited increase in the abduction angle > inconsistent to reported increase in lit.

Question 78

Stress Radiography for the Diagnosis of Medial Glenohumeral Ligament Rupture in Canine Shoulders
Livet 2019

Answer 78

Six adult Beagle cadavers, randomly assigned

Abduction angles were significantly larger in the AS group as measured by goniometer, image analysis and radiographic stress view
than in the NS group.

Shoulder abduction angles measured with a stress radiographspecific view provide objective data that may contribute to diagnosis of medial shoulder instability in dogs.

Question 79

the abduction angle test had good sensitivity but low specificity

while an abduction angle > 50° may be consistent with shoulder instability, itmay also any disorder of the thoracic limb that results in significant loss in muscle strength or muscle mass.

Question 80

Synthetic osteochondral resurfacing for treatment of large caudocentral osteochondritis dissecans lesions of the humeral head in 24 dogs
Murphy 2018

Answer 80

medium-to-large defects located
in the caudocentral aspect

limitations:retrospective nature, Incomplete follow-up was obtained at 12 weeks postsurgery in 8/24 dogs

Although results are encouraging, widespread implementation would be premature without a prospective clinical trial comparing synthetic resurfacing with debridement alone.

complications infection + losening

Question 81

Feline shoulder luxation: a cadaveric study of injury and repair using ligament prostheses
Carwardine 2019

Answer 81

18 cadaveric limbs were randomly allocated into three groups: medial injury, lateral injury or bilateral injury + bone tunnel repair

4/6 medially injured joints > clinically stable
5/6 laterally injured joints > clinically stable. All bilaterally > deemed unstable.

Medial
injury leads to increased valgus and external rotation of the shoulder.
Lateral
injury leads to increased internal rotation but
no significant change in varus movement. Bilateral
injury leads to significant changes in abduction and external rotation beyond
90° of movement.

demonstrates that marked changes in
joint ROM are required before clinical instability is detected

demonstrated that the feline shoulder joint can be repaired using a bone tunnel and prosthetic suture technique, regardless of whether a medial, lateral or bilateral
injury has occurred. This returns the joint to normal….