Page 667 - Adams and Stashak's Lameness in Horses, 7th Edition

Lameness of the Proximal Limb 633

encapsulated by fibrous tissue. Ultimately a synovial like Diagnosis
membrane develops, producing fluid that is similar to The diagnosis can usually be made on physical find-
VetBooks.ir the accumulation of bursal fluid and thickening of the ings alone. However, if the bursa appears infected, radio-
joint fluid although it differs in viscosity and mucin clot.
Subsequently the chronic bursitis is characterized by
graphs should be taken to rule out trauma or infection
bursal wall by fibrous tissue; fibrous bands and septa may involving the olecranon process. If a draining tract is pre-
sent, contrast material may be injected into the tract to
develop in the bursal cavity, and the subcutaneous tissues identify its depth and course. Ultrasound can also be
around the bursa continue to thicken. Bursal enlarge- used to determine whether deeper structures are involved.
35
ment usually develops as a painless swelling that does not
typically interfere with function unless it becomes greatly
enlarged. In most cases, the acquired bursa is only a cos- Treatment
metic blemish unless it becomes infected. An infected In the acute stage, the condition may resolve by pre-
bursa is painful, causes lameness, and may break open to venting further trauma to the region with a shoe boil
drain. The small true bursa that underlies the insertion of roll or boot. The fluid can adjunctively be removed asep-
the triceps brachii muscle is rarely involved.
tically and corticosteroids injected after removal. 34,35
The lesion can be injected more than once. If the initiat-
Etiology ing cause is removed and the lesion is treated before
Acquired bursitis is commonly caused by trauma from extensive fibrosis occurs, it may resolve. However, in
one report, 7 out of 10 horses were treated with intrabur-
the shoe of the affected limb hitting the point of the sal steroids, and none resolved. Surgical intervention
35
elbow during motion or more commonly when the horse after lesion draining and injection is possible. 43
is lying down. American Saddlebreds and Standardbreds There are reports of other substances such as strong
may hit their elbows during exercise. The bursae may 7% iodine being injected into affected bursae with vary-
become infected by a puncture or iatrogenically. 35 ing success. Orgotein has been used, resulting in reduc-
tion but not resolution, as have short‐lived radionuclides
Clinical Signs such as dysprosium‐165. 35
Surgical intervention either by placing drains or en
The condition is characterized by a prominent, often 34,35
freely movable swelling over the point of the elbow, bloc resection appears to have the greatest success.
Open drainage and application of Penrose drains and
which may contain fluid or may be composed primarily pressure bandages over periods of up to 8 weeks was
of fibrous tissue in the chronic stages. Lameness is usu- successful in three horses. En bloc resection is the
87
ally not present unless the bursa is greatly enlarged or treatment of choice for large and mature acquired olec-
infected. Infected bursae feel warm, and firm pressure ranon bursae. Preferentially, the procedure is performed
causes pain (Figure 5.40). standing. Local anesthesia is administered and a curved
skin incision is made over the lateral aspect. A plane of
dissection is made to remove the mass in its entirety.
Excess skin is removed as needed, and the skin is then
closed in a tension‐reducing manner such as widely
placed vertical mattress sutures. A stent bandage is
placed to protect the suture line and provide some com-
pression. The horse can be maintained in cross‐ties or an
overhead wire until satisfactory healing is attained, usu-
ally 2–3 weeks. 35

Prognosis
Conservative treatment of an acquired bursa to
achieve acceptable cosmetic outcome is guarded. En
bloc resection is regarded as a superior way to manage
the lesion with good cosmesis. 34,35 In one report 5 out 6
horses resolved with primary healing after surgery. 75

FRACTURES OF THE HUMERUS
Fractures of the humerus are relatively uncommon in
horses, possibly because of the short, thick configura-
tion of this bone and the prominent surrounding heavy
musculature. The fracture can occur in horses of any
age, breed, or sex, but most often affects foals less than
1 year of age, racing or race training Thoroughbreds,
and horses that are used for jumping or steeplechase
Figure 5.40. A chronic, infected, acquired capped elbow of the events. 14,55,60,96 In a study evaluating 54 horses with
left forelimb. Source: Courtesy of Dr. Gary Baxter. humeral fractures, the mean age for fracture occurrence