Objective—To determine clinical signs, diagnostic
findings, and outcome for horses with desmitis of the
straight sesamoidean ligament (SSL) near its insertion
on the middle phalanx.
Procedure—Medical records were reviewed, and
information on signalment, history, clinical signs, diagnostic
findings, and treatment was obtained. Followup
information was obtained through telephone conversations
Results—In all horses, the diagnosis was made by
use of high-resolution ultrasonography. Seven horses
had moderate lameness on initial examination; lameness
was exacerbated in 6 horses following flexion of
the distal limb joints. The cause of lameness could
not be determined on the basis of clinical signs, and
diagnostic local anesthesia was necessary to localize
the source of lameness to the distal portion of the
limb. Five horses had forelimb involvement (1 bilateral),
and 4 had hind limb involvement (1 bilateral).
Treatment consisted primarily of a 6-month rest and
rehabilitation program. Six of the 9 horses were able
to return to their intended use.
Conclusions and Clinical Relevance—Results suggest
that injury to the SSL proximal to its insertion on
the middle phalanx should be considered as a possible
cause of lameness in horses, particularly performance
horses, with lameness localized to the distal
portion of the forelimb or hind limb that do not have
any radiographic abnormalities. High-resolution ultrasonography
was necessary to make the diagnosis.
Horses with an acute injury appeared to have a reasonable
chance of responding to treatment and
returning to their intended use. (J Am Vet Med Assoc 2003;222:973–977)