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Scientific Proceedings Equine Programme
Proximal Limb Lameness in the Horse
Thomas K. Hughes, MA VetMB CertES(Orth) MRCVS, The Liphook Equine Hospital, Forest Mere, Liphook
Hampshire. GU30 7JG, UK, [email protected]
Principles
Lameness associated with structures proximal to the elbow and
stifle is uncommon but poses a
particular challenge in terms of
diagnosis. The accurate placement
of local anesthetic solution within
or around proximal limb structures
can be difficult owing to a lack of
practice and their deep location. The structures of the
proximal limb are covered by muscle and closely
associated with the thorax and pelvis limiting the number of radiographic views that it is possible to obtain. As
a result, scintigraphic and, increasingly, ultrasonographic
308 | Abstracts European Veterinary Conference Voorjaarsdagen 2008
examination of affected structures is important in
establishing a diagnosis. Treatment of many of the
diseases in this region is symptomatic and revolves
around corticosteroid injection or infiltration combined
with a rest and rehabilitation program. The outcome in
such cases varies with the disease identified.
Intertubercular Bursa
As it passes over the point of the shoulder, the biceps
tendon divides into medial and lateral lobes that lie
within the two grooves formed by the cranial parts of the
greater and lesser tubercles and the intermediate tubercle of the humerus (1). The synovial intertubercular bursa
(bicipital bursa) lying between the bilobate tendon and
Scientific Proceedings Equine Programme
Conditions affecting the proximal humerus that may
improve to analgesia of the intertubercular bursa include
both septic and non-septic bursitis, tendonitis of biceps
brachii, osteitis of the humeral tubercles, osseus cyst-like
lesions of the proximal humerus in communication with
the bursa and fragmentation of the supraglenoid
tubercle(2,5,6). Treatment of non-septic conditions revolves
around intrathecal medication with corticosteroids and
sodium hyaluronate combined with rest and in some
cases bursoscopy. Septic bursitis requires directed lavage
via bursoscopy. As a general rule, conditions that resolve
without enlargement of the tendon, roughening of the
surface of the humerus, or adhesion formation within
the bursa have a fair prognosis for return to athletic
function. Any condition that affects the smooth
movement of the tendon through the grooves of the
humerus will lead to chronic lameness(2).
Figure 1. A - Lateral scintigraphic image of the right shoulder
of a 25 year old Arab gelding showing marked increased
radiopharmaceutical uptake over the scapulohumeral
joint. B - Mediolateral radiograph of the right shoulder of
the same horse as in A showing marked degeneration of
the scapulohumeral joint.
the humerus, facilitates movement of the tendon within
the intertubercular groove. The biceps muscle flexes the
elbow joint, tenses the fascia of the forearm and fixes
the shoulder and elbow during weight bearing (1), therefore, abnormalities of the proximal tendon tend to lead
to abnormalities of limb protraction during the swing
phase of the stride as well as during weight bearing(2).
Lameness may be sudden and severe, or mild and
insidious in onset; lameness may only be observed when
the horse is ridden in an outline or lunged with side reins.
Abnormalities of the intertubercular bursa are rarely
painful on palpation (2).
An intrathecal injection of local anesthetic solution
should improve lameness associated with the
intertubercular bursa. Several techniques are described
and the accuracy of the injection is improved by
ultrasound guidance(3). Abnormalities of the proximal
humerus may be apparent on scintigraphy and radiography but lesions affecting the biceps tendon or bursa
are most apparent on ultrasonographic examination and
the ultrasonographic anatomy of the bursa has been
well described(4). Endoscopic evaluation of the bursa has
been well described and allows inspection of the fibrocartilage covered surface of the intertubercular grooves
of the humerus as well as the biceps tendon itself (5).
Sacroiliac disease
The sacroiliac joint lies between the wing of the ilium
and the wing of the sacrum supported by extensive
sacroiliac ligaments, the anatomy of which has been well
described(7). The joint is flat, L-shaped and orientated at
approximately 30 degrees to the horizontal plane. The
sacral surface of the joint is covered by hyaline cartilage
and the iliac surface is covered by fibrocartilage and,
though the joint surface area is large, it contains only
approximately 1ml of synovial fluid(8). Though there is
evidence that inflammatory and degenerative disease
can affect the joint and the supporting sacroiliac
ligaments, the site from which pain originates in most
horses (and humans) affected by lameness associated
with the sacroiliac region is unknown(8,9,10).
Lameness originating from the sacroiliac region may be
acute and marked, mild and insidious in onset, or present
as poor performance rather than overt lameness(10,11). If
disease is acute then resentment may be seen to digital
pressure over the lumbosacral region, the tuber sacrale
or tuber coxae and any lameness present may be
exacerbated by flexion or abduction tests(10,11). In more
Figure 2. A transverse
ultrasonographic
image of the lateral
lobe of the biceps
brachii tendon of the
right forelimb of a 13
year old TB gelding
showing enlargement
and heterogeneity of
the tendon indicative
of tendonitis.
Abstracts European Veterinary Conference Voorjaarsdagen 2008 | 309
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Scientific Proceedings Equine Programme
chronic cases, overt lameness is frequently absent as are
any localizing signs(9).
number of cases of sacroiliac disease, has not, to the
author’s knowledge, been published.
As few localizing signs may be apparent on clinical
examination, diagnostic analgesia is of great importance
in diagnosing sacroiliac disease. The sacroiliac joint is
inaccessible to standard injection techniques but in the
majority of affected horses, local anesthetic infiltration
of the sacroiliac region immediately adjacent to the joint
will lead to an improvement in lameness(9). Several
injection techniques have been reported(12). Care must be
taken to avoid anesthesia of the sciatic nerve particularly
if bilateral blocks are performed. A volume of local
anesthetic greater than 10ml is likely to diffuse over a
large area, confounding diagnosis and making unwanted
neurological signs more likely(12).
References
1. Sisson S. Equine mycology. In:Getty R. Eds. Sisson and Grossman’s The
Anatomy of the Domestic Animals. Philadelphia: WB Saunders,
1975;376-453
2. Dyson SJ. The elbow, brachium and shoulder. In: Ross MW, Dyson SJ.
Eds. Diagnosis and Management of Lameness in the Horse.
Philadelphia: Saunders, 2003;399-416
3. Schumacher J, Livesey L, Brawner W, Taintor J, Pinto N. Comparison of
2 methods of centesis of the bursa of the biceps brachii tendon of
horses. Equine vet J 2007;39:356-9
4. Crabill MR, Chaffin MK, Schmitz DG. Ultrasonographic morphology
of the bicipital tendon and bursa in clinically normal quarter horses.
Am J Vet Res 1995;56:5-10
5. McIlwraith CW, Nixon AJ, Wright IM, Boeing KJ. In: McIlwraith CW,
Nixon AJ, Wright IM, Boeing KJ. Eds. Bursoscopy. Edinburgh: Elvsevier,
2005; 409-426
6. Coudry V, Allen AK, Denoix JM. Congenital abnormalities of the
bicipital apparatus in four mature horses. Equine vet J 2005;37:272275
7. Sisson S. Equine syndesmology. In:Getty R. Eds. Sisson and
Grossman’s The Anatomy of the Domestic Animals. Philadelphia:
WB Saunders, 1975;349-375
8. Goff LM, Jeffcott LB, Jasiewicz J, McGowan CM. Structural and
biomechanical aspects of equine sacroiliac joint function and their
relationship to clinical disease. The Veterinary Journal
2007;doi:10.1016/j.tvjl.2007.03.005
9. Dyson S, Murray R. Pain associated with the sacroiliac joint region: a
clinical study of 74 horses. Equine vet J 2003;35:240-245
10. Jeffcott LB. Disorders of the thoracolumbar spine of the horse - a
survey of 443 cases. Equine vet J 1980;12:197-210
11. Haussler KK. Diagnosis and management of sacroiliac joint injuries.
In: Ross MW, Dyson SJ. Eds. Diagnosis and Management of Lameness
in the Horse. Philadelphia: Saunders, 2003;501-508
12. Engeli E, Haussler KK. Review of sacroiliac injection techniques. In:
50th Annual Convention of the American Association of Equine
Practitioners, 2004, Denver, Colorado. Ithaca: International
Veterinary Services (www.ivis.org) P1466.1204
13. Gorgas D, Kircher P, Doherr MG, Ueltschi G, Lang J. Radiographic
technique and anatomy of the equine sacroiliac region. Vet radiol &
ultrasound 2007;48:501-506
14. Erichsen C, Berger M, Eksell P. The scintigraphic anatomy of the
equine sacroiliac joint. Vet radiol & ultrasound 2002;43:287-292
15. Tomlinson JE, Sage AM, Turner TA. Ultrasonographic abnormalities
detected in the sacroiliac area in twenty cases of upper hindlimb
lameness. Equine vet J 2003;35:48-54
16. Engeli E, Yeager A, Haussler KK. Use and limitations of
ultrasonography in sacroiliac disease. In: 50th Annual Convention of
the American Association of Equine Practitioners, 2004, Denver,
Colorado. Ithaca: International Veterinary Services (www.ivis.org)
P1468.1204
Diagnostic imaging of the sacroiliac region is a challenge.
Radiography is only possible in small anesthetized
horses(13). Scintigraphy is useful in identifying inflammation of the sacroiliac joints however, diagnosis should
not be based on scintigraphic findings alone as there is
significant overlap in the appearance of this region
between normal horses, horses affected by sacroiliac
disease and horses affected by other causes of hindlimb
lameness(9,14). Ultrasonographic examination of the dorsal
sacroliliac ligaments, tuber sacrale, iliac wings, and
lumbosacral junction is possible but subtle lesions are
difficult to identify and the clinical significance of any
abnormal findings is presently unknown. Transrectal
ultrasonography may be used to image the ventral
aspect of the sacroiliac joints but the same limitations
apply(15,16).
Treatment of sacroiliac disease includes the local
infiltration of corticosteroids combined with a rest and
rehabilitation program(11). In human patients a specific
physiotherapy program based on biomechanical findings
is employed but as yet our lack of understanding of
sacroiliac disease in horses means that such therapy is
not available(8). Long-term follow-up on a meaningful
310 | Abstracts European Veterinary Conference Voorjaarsdagen 2008