Chapter 98 - Shoulder Flashcards
Why can treatment of shoulder pathologies be delayed?
Shoulder pathologies are difficult to diagnose.
what is a common consequence of delayed treatment of shoulder injuries?
Secondary osteoarthritis.
What advancements can help with earlier diagnoses of shoulder lameness?
Improved radiographic equipment.
What can help improve outcomes for shoulder lameness in horses?
New plating methods for supraglenoid tubercle fractures.
How can shoulder lameness be localized in some cases?
Through swelling or pain on palpation.
What diagnostic method is used when clinical examination is inconclusive?
Intraarticular or bursal anesthesia.
What are the signs of acute shoulder injury in horses?
Severe lameness and localized swelling.
Why is joint effusion difficult to palpate in shoulder injuries?
Due to the overlying musculature.
What are less specific signs of shoulder lameness?
Shoulder muscle atrophy, pain on extension or flexion, and a shortened anterior phase of stride.
Which imaging technique can help localize shoulder lameness?
Nuclear scintigraphy.
What imaging technique should be used if bicipital bursitis is suspected?
Ultrasonography.
Why is MRI not commonly used for diagnosing shoulder injuries in horses?
It is not currently available for imaging equine shoulders.
How should radiographs of the shoulder joint be taken?
The horse’s leg is extended forward for a mediolateral projection.
What should be done if radiographs do not reveal shoulder pathology but osteochondrosis (OC) is suspected?
Perform positive-contrast radiography using iodine-based contrast medium. 7 to 10 mL of 350 mg iodine/
mL iohexol or a similar sterile water-soluble iodinated contrast
medium should be performed
What is injected to obtain a double-contrast radiograph?
30 mL of air following positive-contrast radiography.
How reliable is ultrasonographic guidance for intrasynovial anesthesia?
It is 100% reliable.
What can happen if the suprascapular nerve is inadvertently blocked during shoulder joint anesthesia?
It can cause lateral subluxation, leading to a condition known as sweeney.
Where is the bicipital bursa located for injection?
20 G Approximately 4 cm proximal to the distal aspect of the deltoid tuberosity. Btw the biceps brachii muscle and the humerus directed proximomedial to approximately 4 cm in depth where 5 to 10 mL of LA are injected
How is the infraspinatus bursa injected?
A 20-gauge needle is inserted through the infraspinatus tendon, distal to the caudal border of the greater humeral tubercle. 5 mL of LA is injected
painful response can often
be elicited following deep palpation of the
notch between the
cranial and caudal parts of the greater tubercle of the humerus.
What are radiographs performed for diagnosis of shoulder disease?
cranioproximal–craniodistal oblique view of the proximal portion of the humerus to diagnose long oblique fractures of the greater tubercle (Figure 98-1)
Figure 98-1. The position for obtaining a cranioproximal–craniodistal oblique view of the proximal portion of the humerus, which is best for imaging fractures of the greater tubercle.
Describe the local intra-articular injection of the shoulder - be specific
Local anesthetic (20 mL) is injected into the shoulder joint using an 18-gauge, 8.9-cm (3.5-in) spinal needle inserted in the notch between the cranial and caudal parts of the greater tubercle of the humerus. The needle is directed toward the elbow of the opposite limb, parallel to the ground, and is advanced until bone or cartilage is contacted
Why you should be careful with anesthesia of the scapulo humeral joint?
Extrasynovial deposition or leakage of local anesthetic solution out of the shoulder joint can block the suprascapular nerve, resulting in lateral subluxation of the scapulohumeral joint, thereby producing the clinical appearance of sweeney.
Is osteochondrosis (OC) common in the shoulder joint?
No, it is less common compared to other joints.
At what age do clinical signs of shoulder OC usually appear in horses?
Between 4 to 12 months old.
What are typical radiographic signs of OC in the shoulder joint?
Irregular subchondral bone with radiolucent areas surrounded by sclerosis.
How can the extent of cartilage flaps be more clearly delineated?
Through contrast radiography.
What diagnostic tool should be used if subtle cartilage lesions are not detected with radiography?
Diagnostic arthroscopy.
What develops rapidly in cases of shoulder osteochondritis dissecans (OCD)?
Secondary osteoarthritis (OA).
What is a radiographic sign of shoulder OA?
Flattening of the humeral head and glenoid cavity.
What is the treatment of choice for shoulder OCD lesions?
Arthroscopic surgery with débridement.
What material has been used to repair cartilage flaps in select OCD cases?
Polydioxanone pins.
Why is shoulder arthroscopy more technically challenging than other joints?
Due to the complex anatomy and limited accessibility.
What approach is most commonly used for shoulder arthroscopy?
The craniolateral approach.
Where is the cranial portal site located for shoulder arthroscopy?
Between the cranial and caudal parts of the greater tubercle of the humerus.
Which approach is preferred for lesions on the caudal or medial aspect of the humeral head?
The lateral approach.
What is used to distend the joint during shoulder arthroscopy?
60 mL of lactated Ringer’s solution.
What instruments are used for subchondral bone débridement?
Ferris-Smith rongeurs, motorized resectors, periosteal elevators, and curettes.
What is done after cartilage and bone débridement is complete?
The joint is lavaged to remove debris.
What medications are administered perioperatively?
Antimicrobials and phenylbutazone.
How long should stall rest be maintained postoperatively?
30 days.
When does hand walking begin after shoulder arthroscopy?
After 14 days of stall rest.
How long should horses be turned out before resuming exercise?
For 4 to 6 months.
What are the 2 arthroscopic approach described for the shoulder?
Lateral and craniolateral approach
The lateral approach provides maximal visualization of the medial aspect of the humeral head and leaves the cranial portal where do you place the second portal for insertion of an egress cannula?
cranial to the infraspinatus tendon and proximal tothe notch between teh cranial and caudal parts of the greater tubercle of the humerus
describe the position of the horse for arthroscopy of the shoulder
lateral recumbency with the affected limb uppermost
Joint is distended previous to surgery with how much fluid?
60 mL of lactate Ringer’s solution using 18G needle
where do you insert the needle to distend the shoulder joint previous to the surgery?
inserted in the notch between the cranial and caudal parts of the greater tubercle of the humerus (this site becomes the cranial portal)
Figure 98-2. (A) Mediolateral radiograph of the shoulder joint. A subchondral lucent region is present in the caudal humeral head (arrows). The humeral head in this region also appears mildly flattened. (B) A positive contrast arthrogram of the same shoulder joint depicted in (A) Contrast material outlines the shoulder joint and further delineates the extent of subchondral bone lysis (arrows).
Figure 98-3. (A) Mediolateral radiograph of the shoulder joint. A subchondral bone lucency is present in the glenoid cavity. (B) A positive contrast arthrogram of the same shoulder joint as depicted in (A) shows that the subchondral bone lucency most likely does not communicate with the articular environment.
Figure 98-4. Mediolateral radiograph of the shoulder joint. Severe OCD of the humeral head and opposing glenoid cavity resulting in the development of osteoarthritis with sclerosis of the humeral head and glenoid cavity, remodeling of the caudal glenoid, and severe flattening of the caudal humeral head.
describe the insertion of the athroscope in the craniolateral approach
the arthroscope is inserted immediately cranial to the infraspinatus tendon and proximal to the notch between the cranial and caudal parts of the greater tubercle
The arthroscope is angled 25 degrees distal and caudal to enter the shoulder joint
describe the lateral approach for athroscopy of shoulder?
the arthroscope is inserted 1 to 2 cm caudal to the caudal border of the infraspinatus tendon and inserted in the same direction as for the craniolateral approach. The optimal site for instrument portal entry is determined using an 18-gauge spinal needle.
what is the posoperative care of shoulder arthroscopy for OCD?
AB + PBZ
PBZ is continued for the next 5 to 10 days.
Horses are restricted to stall rest for 14 days, at which time hand walking begins for 5 minutes per day.
After 30 days of stall rest with hand walking, horses are turned out for 4 to 6 months before exercise is resumed.
The most recent reports indicates a prognosis for soundness of how much?
25% = poor
Figure 98-6. Mediolateral radiograph of the shoulder joint. A displaced fracture of the supraglenoid tubercle is seen. The fracture fragment is displaced craniad and dorsad.
Figure 98-5. (A) An arthroscopic image demonstrating elevation of an OCD lesion of the humeral head (H). (B) A probe is inserted into a cystic defect in the glenoid cavity (G). (C) Use of a motorized burr to débride a lesion in the glenoid cavity.
C) Use of a motorized burr to débride a lesion in the glenoid cavity.Figure 98-5. (A) An arthroscopic image demonstrating elevation of an OCD lesion of the humeral head (H). (B) A probe is inserted into a cystic defect in the glenoid cavity (G). (C) Use of a motorized burr to débride a lesion in the glenoid cavity.
Lesions in arthroscopy are more extensive or less extensive than suggested by radio?
more
Pouyet et al 2021 VSWhat was the primary objective of the study described in the abstract?
A) To develop a new surgical technique for horses B) To compare different types of arthroscopes C) To describe the technique for performing diagnostic standing scapulohumeral joint needle arthroscopy in horses D) To study postoperative complications in horses
C) To describe the technique for performing diagnostic standing
In phase 1, what was the focus of the evaluation in the study?
A) Comparing the recovery time of horses B) Evaluating the visible structures of the scapulohumeral joint using two types of arthroscopes C) Testing a new type of sedation for horses D) Measuring postoperative pain levels in horses
B) Evaluating the visible structures of the scapulohumeral joint using two types of arthroscopes
What was one limitation of the standing needle arthroscopy technique mentioned in the conclusion?
A) The procedure caused significant postoperative complications B) The technique was too complex for routine use C) It prevented evaluation of the medial aspect of the humeral head and most of the glenoid cavity D) Horses required general anesthesia for the procedure
C) It prevented evaluation of the medial aspect of the humeral head and most of the glenoid cavity
Pouyet concluded that the centrolateral aspect of the joint was visible in all joints byt the other craniolateral and caudolateral were what?
were complete in half of the cases and partial in other half
medial side is NOT visible standing approach
Pouyet et al 2021 VS describes the surgical approach of craniolateral how?
3-mm skin incision was made with a No. 11 scalpel blade proximal to
the greater tubercle of the humerus but slightly toward the
cranial part of the tubercle to facilitate exploration of the
cranial aspect of the joint.
Then, an instrument
portal was created approximately 6 cm caudal to the infraspinatus tendon and 4 cm distal to the arthroscopic
portal to assess the lateral to medial visibility of the
humeral head during arthroscopy
Fractures in the supraglenoid tubercle are usually what type?
are usually simple, intraarticular epiphyseal fractures.
At what age are horses most commonly affected by supraglenoid tubercle fractures?
younger than 2 years old
What are two potential causes of supraglenoid tubercle fractures?
Direct trauma or avulsion fractures caused by tension from the biceps tendon.
Can horses with supraglenoid tubercle fractures bear weight?
Yes, but they are variably lame and reluctant to fully extend the affected limb.
Figure 98-7. (A) Mediolateral radiographic projection of a supraglenoid tubercle fracture. The fracture involved minimal articular surface of the glenoid cavity making surgical removal of the fragment an option. (B) Six years after removal of the fracture fragment, the horse remained sound with no signs of shoulder osteoarthritis.
Figure 98-8. Mediolateral radiograph of the same shoulder joint depicted in Figure 98-6 after internal fixation of the fracture using two 4-hole, 4.5-mm narrow locking compression plates with 5.0-mm locking head screws.
Figure 98-9. Mediolateral (left) and craniocaudal radiographic views of supraglenoid tubercle fracture repaired with the help of a human distal femoral LCP.
Figure 98-10. Illustration of a repair of a neck fracture of the scapula with the help of two 6-hole LCPs (A) and a 5-hole human distal femur LCP (B).
Figure 98-11. Cross-sectional view across the body of the scapula distant to the fracture of the scapular body or neck. One LCP is applied cranial and another one caudal to the scapular spine. A, Cranial edge; B, spine; C, caudal edge.
Figure 98-12. (A) Lateral view of marked atrophy of the infraspinatus and supraspinatus muscles. Note the well-defined spina scapulae. (B) Frontal (left) and side view (right) of a horse, A showing the marked atrophy of shoulder muscles. The dots on the left picture at the respective points of the shoulder on the left and right side of the horse show difference in posture.
