51. Shoulder Flashcards
glenoid physis and proximal humeral physis fusion times
glenoid–6 monthsproximal humeral physis–1 yr
collateral ligaments of the shoulder
medial collateral or glenohumeral ligament (Y)lateral collateral or glenohumeral ligament (single)
passive stabilizers of the shoulder joint
passive (static) stabilizers–allow wide ROM–increases laxity while flexed–joint volume, adhesion/cohesion mx, concavity compression, capsuloligamentous restraints
active stabilizers of the shoulder joint
active (dynamic) stabilizers–infra/supraspinatus-subscapularis–teres major
sensory receptors in shoulder collateral ligaments for passive stability and joint stability
type I (Ruffini) receptorsmost common and densely packed on cranial aspect of the scapular side of the ligament
normal dog and cat ROM (goniometry)
flexion dog 57 cat 32extension dog 165 cat 164
describe arthrocentesis of the shoulder
sedate, aseptic technique22 gauge needledirect craniolateral to caudomedial btwn greater tubercle and acromion
ddx for shoulder OA
usually a secondary condition to….1. fractures2. OC/OCD3. incomplete ossification of caudal glenoid4. chondocalcinosis5. glenoid dysplasia6. traumatic luxation
diagnostics for shoulder pathology
- PE, ORTHO, NEURO2. Arthrocentesis3. radiographs (include stressed abduction views, +/- arthrography)4. CT bone5. US tendons6. MRI soft tissues7. arthroscopy
one current limitation for US of soft tissues surrounding the shoulder
inability to properly visualize the medial joint structures
what percent of extraarticular structure pathology would have been missed on arthroscopy alone vs MRI
15% of shoulder pathology would have been missed on arthroscopic exam bc of its extraarticular location
T/FOsteochondrosis dissecans is a disease of intramembranous ossification
FALSEendochondral ossificationmost commonly caudocentral or caudomedial humeral head
signalment of OC/OCD of shoulder
large-giant breed dogs27-68% bilateralpain on shoulder EXTENSION
radiographic changes for shoulder OC/OCD
–loss of trabecular structure–subchondral bone lysis–subchondral bone defect–gas accumulation in joint space (cavitation, vacuum phenomenon)–flattening or irregularity of humeral head–mineralized loose bodies in caudal joint pouch or in tendon sheath of biceps brachii
what percentage of NONmineralized cartilage flaps within biceps brachia tendon sheath occur in OC/OCD lesions
10% miss by conventional radiographs
T/Fbevel the cartilage edges during debridement of OC/OCD lesions
FALSE avoid beveling the edges of the defect to decrease the risk of fibrillation and erosion of the cartilage of the corresponding surface of the glenoid cavity
approaches to the shoulder/humeral head for OC/OCD removal
- craniolateral approach–+/-tenotomy of infraspinatus/teres minor, +/- osteotomy of acromion, increased exposure, but decrease ROM2. caudal approach–less loss of shoulder ROM and increased weight bearing 1 month post op; caudal to scapular part of deltoid muscle; axillary nerve3. caudolateral approach–btwn two muscle bellies of deltoid +/- teres minor tenotomy
glenoid dysplasia leads to what shoulder instability
medial luxation
how do animals with medial shoulder luxation hold their limb
elbow flexedadductiondistal extremity abducted
treatment options for glenoid dysplasia
–excision arthroplasty +/- excision of the humeral head (“false joint”)–arthrodesis implant failure, delayed union–not shown to be better than excision arthroplasty (lg transarticular lag screw, diverging kwire, plates 105-110 degrees)–amputation
proper osteotomy angle to perform glenoid excision
approach to shoulder = lateraldistolateral to proximomedial osteotomyavoid SUPRASCAPULAR nerve
what is multiple epiphyseal dysplasia
rare autosomal recessive genetic disorder defect in ossification of epiphysis (multiple bones)seen at 8 weeks of ageseverely lameeuthanized
what is pseudogout
chondrocalcinosisdeposition of hydroxyapatite in the articular cartilagefound in plateau region of the humeral head of Greyhoundsunknown clinical relevance
most common should lameness in dogs
biceps brachii tendinopathyorigin supraglenoid tubercle(hypovascular area)primary dz due to inflammation from overuse or chronic repetitive injury secondary dz due to intraarticular disease or cartilaginous loose body entrapments or trauma related
diagnosis of biceps tendon pain
- drawer test (does not test instability)2. biceps tendon test (elbow extension, shoulder flexion)3. biceps retraction test
imaging for biceps tendinopathy
–survey films–arthrography–flexed craniodistal cranioproximal SKYLINE to ID irregularities/mineralization in intertubercular groove–US–MRI
treatment options for biceps tendinopathy
- 1-2 injections long acting GCC, cage restsurgical options1. open tendonesis–tendon or origin to proximal humerus2. arthroscopic tendonesis3. percutaneous +/- US guided tenotomy4. open or arthroscopic tenotomy5. blind tenotomy
differentials for biceps brachii disease
- biceps tendinopathy (most common)2. medial displacement biceps brachii (rupture transverse ligament)3. tendon rupture of biceps brachii (avulsion, midsubstance, direct laceration)4. dystrophic mineralization of biceps brachii
supraspinatus injury in dogs
attaches to greater tubercleRotts and Labs+/- incidentalmay represent avascular region of tendonpain on palpation+/- concurrent biceps brachiitreat: rest, NSAIDS, debride, tenotomy
most common direction of shoulder luxation from shoulder instability
MEDIAL (80%)
treatment options for shoulder luxation
- transposition of biceps tendon or supraspinatus tendon (success 85%)2. augment collateral ligament with prosthetic suture reconstruction (screws/bone anchors and suture)3. imbrication of the tendon of the subscapularis muscle4. radio frequency induced thermal capsulorrhaphy via arthroscopy (tightens for stability)-caution axillary neuropathy5. arthrodesis6. excison arthroplasty
T/Ftraumatic shoulder luxations in large to giant breed dogs are generally laterally
TRUEAVOID VELPEAU with lateral laxations to avoid ADDUCTION; USE SPICA
disruption of muscle fibers most commonly occurs near____________
the musculotendinous junction
infraspinatus muscle contracture characteristic gait
fibrous connective tissue replacing muscle secondary to degenerative changes as a result from traumabiphasic history (acute pain that improves then chronic lameness ensues)Muscle atrophy over spineelbow adducted shoulder abducted and ante brachium externally rotatedCIRCUMDUCTION of limb
