Page 517 - Adams and Stashak's Lameness in Horses, 7th Edition

Lameness of the Distal Limb 483

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Figure 4.55. Dorsopalmar radiograph of the distal phalanx of a lame horse revealed a focal radiodense area in the center of the distal
phalanx (left; arrow) that was confirmed with MRI (right; arrow). The lesion was later identified as a well‐circumscribed P3 sequestrum.

Penetrating injuries that involve bone, tendon, or syn-
ovial cavities require more aggressive treatment depend-
ing on the deeper structure that is involved. Typical
treatments include both systemic (IV) and local (IV
regional perfusion and intrasynovial) antimicrobials,
NSAIDs, local debridement of the wound, and lavage,
endoscopy, or arthroscopy if a synovial cavity is
involved. Wound debridement may be performed in the
standing patient, but it usually best performed with the
horse under general anesthesia. Lavage, endoscopy, or
arthroscopy of a synovial cavity usually requires general
anesthesia. Wounds that penetrate the distal phalanx
should be enlarged and the distal phalanx curetted if
possible as further progression of the infection into the
bone is not uncommon (Figure 4.56). Soaking the foot
to lavage deep wounds of the foot is generally not
recommended. Involvement of the navicular bursa is Figure 4.56. Sagittal section of P3 in a horse that sustained a
best treated with endoscopy or lavage and local debride- puncture wound to the solar surface of P3. Subsequent infection of
ment of the defect in the frog. 1,2,33 See the section on P3 contributed to a pathologic fracture of the bone and involvement
musculoskeletal emergencies in Chapter 12 for further of the DIP joint.
information.
following solar foot penetration have a poor prognosis
Prognosis (36% and 29% in two recent studies) for return to pre-
10,18
Horses with penetrating injuries that do not involve injury athletic function. In general, prompt treat-
ment of any penetrating injury to the foot regardless of
bone, tendon, or a synovial cavity typically do very the structure(s) involved improves the chance of a suc-
well. Horses with penetrating injuries outside the frog cessful outcome. 2,18
18
or frog sulci and centrally located in the foot also do
well. A recent study reported that 91% of horses with
penetrating injuries of the foot without synovial involve- KERATOMA
ment and treated conservatively returned to their previ-
ous level of soundness. In another study of 50 horses Keratoma is an uncommon condition of the hoof
18
with deep puncture wounds of the foot, 95% of horses that is characterized by keratin‐containing tissue
with injuries outside the frog or frog sulci regained full growing between the hoof wall and the distal phalanx.
athletic soundness. Horses with synovial involvement Although the term implies a neoplastic process, histologic
32