Page 784 - Adams and Stashak's Lameness in Horses, 7th Edition

750 Chapter 5

Prognosis The foregoing symptoms should be used in diagnosis.
The condition is difficult to differentiate from inflamma-
The prognosis is good for soundness and future use.
VetBooks.ir Clinical problems or lameness is uncommon. The prog- common, may be confused with spavin lameness. A
tion of the coxofemoral joint. The lameness, which is not
nosis after surgery is guarded, depending upon the size
lameness of unknown cause is sometimes ascribed to tro-
of the lesion due to potential for incisional
complications. 5,22,43 chanteric bursitis. Injection of a local anesthetic into the
bursa is helpful in differentiating the condition from cox-
ofemoral joint osteoarthritis (OA). Nuclear scintigraphy
TROCHANTERIC BURSITIS (TROCHANTERIC should identify the area as inflamed. Toth et al. compared
LAMENESS, WHIRLBONE LAMENESS) 81 four different techniques for trochanteric bursa centesis
and concluded that centesis performed using a spinal nee-
Trochanteric bursitis is inflammation of the bursa dle with the ipsilateral foot non‐weight‐bearing and
beneath the tendon of the accessory gluteal muscle (deep placed in a Hickman block positioned caudal to the
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portion of the gluteus medius muscle) as it passes over contralateral foot. Using the ultrasound can further
the greater trochanter of the femur. The tendon of the increase the likelihood of successful centesis. 93
gluteus medius muscle also may be involved, as well as
the cartilage over the trochanter. The deep portion of the Treatment
gluteus medius muscle has a strong flat tendon that
passes over the convexity of the trochanter before it It is important to address any associated source of
inserts into the crest, and it functions to extend the cox- lameness. Rest and anti‐inflammatory treatment may be
ofemoral joint and to abduct the limb. The trochanter is helpful in some cases. Injection of the bursa with corti-
covered with cartilage and the trochanteric bursa is coids appears to be the most effective method of treat-
interposed between it and the tendon. 30 ment. The authors have had success in treating the bursa
with shockwave (1–3 treatments). Other reported treat-
ments consist of injections of Lugol’s solution of iodine
Etiology
into or around the bursa as a counterirritant. Hot packs
In many cases, there is a concurrent source of applied to the affected area in the acute stages relieve
chronic lameness in the same limb, particularly distal some pain. Phenylbutazone therapy for 3–4 weeks may
tarsitis. Chronic forelimb lameness may also contrib- be useful. Treatment is difficult when the cartilage or
ute to trochanteric bursitis by causing the horse to bone has been damaged with fracture or periostitis.
place more strain on the hindlimbs. 12,37 Lameness may Although surgery may be indicated in these cases, no
also be caused by bruising as a result of the horse fall- reports could be found regarding the use of surgery.
ing on the affected side or by strain during racing or
training. Prognosis
Trochanteric bursitis occurs in horses racing on small
tracks, where the turns are close together, and in horses The prognosis is usually associated with the progno-
working on their hindlimbs that are frequently exercised sis of a second source of lameness. If the other source is
in soft, deep arenas. Short heels and long toes in the treated, as well as the bursa, the horse will usually return
hindfeet seem to predispose to this lameness. When the to soundness within 4–6 weeks. However, if there is no
etiology is severe trauma, such as a direct kick, the car- other source of lameness, or the injury is more severe,
tilage or the bone of the trochanter may be fractured, the prognosis is guarded to unfavorable, and the lame-
causing persistent lameness. It also has been found fol- ness may remain indefinitely or may recur when the
lowing an attack of strangles. horse is put back into training.

Clinical Signs and Diagnosis RUPTURED QUADRICEPS MUSCLE
Pain may be evident when pressure is applied over the
Ruptured quadriceps muscle is a rare condition that
greater trochanter. Careful interpretation is required, causes the horse to present with a dropped stifle.
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because some horses naturally tend to shy away when
pressure is applied over the hip joint. When pushing on A single case of unknown etiology was observed in a
nursing foal. The patella was prominent due to the cra-
the greater trochanter, a normal horse should lean back 82
into the clinician, but in cases of trochanteric bursitis, nial position of the stifle without the quadriceps attachment.
Anecdotally, quadriceps rupture has been observed fol-
horses will move away from the examiner. At rest, the
limb may remain flexed; as the horse moves, weight may lowing extensive resection of a calcified and fibrotic
mass causing a fibrotic myopathy.
be placed on the inside of the foot so that the inside wall
of the foot wears more than the outside wall. This can be
best seen when observing the horse from behind—the THE COXOFEMORAL JOINT
foot is carried inward and the horse sets the foot down
on a line between the forelimbs. The horse tends to The femoral head and the acetabulum form a ball‐
travel “dog fashion” since the hindquarters move toward and‐socket articulation that makes up the coxofemoral
the sound side because the stride of the affected limb is joint. The heavy musculature and extensive ligament
shorter than that of the sound side. After the condition network surrounding and within the joint make the hip
has been present for some time, atrophy of the gluteal joint inherently stable. The transverse acetabular liga-
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muscles occurs. ment, ligament of the head of the femur (round), and