Page 557 - Adams and Stashak's Lameness in Horses, 7th Edition

Lameness of the Distal Limb 523

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A B

C D

Figure 4.102. Lateral (A), dorsoplantar (B), and two oblique (C and D) radiographic projections of a horse with a comminuted P2 fracture.
Multiple fracture lines are commonly seen, and most comminuted fractures involve both the PIP and the DIP joint surfaces.

Comminuted fractures are the most common fracture
involving P2. They nearly always involve the PIP joint Etiology
(uniarticular) but often extend distally into the DIP joint Osteochondral fractures may occur from use, direct
(biarticular). A variety of fracture configurations are pos- trauma to the bone (e.g. a penetrating wound), or avul-
sible, but typically multiple fracture lines oriented in sev- sion of soft tissue attachments (palmar/plantar aspect),
eral directions are visible on radiographs. In addition, it or they may be developmental associated with OC.
is not uncommon for these fractures to resemble a “bag Palmar/plantar eminence fractures may occur from
of ice” due to the multiple fracture fragments. Although compression and rotation that is associated with sudden
comminuted P2 fractures result in marked instability of stops and short turns. They may also occur during PIP
the pastern region, they are rarely open. Proper immobi- joint overextension, which results in excessive tension of
lization of comminuted P2 fractures prior to transport to the SDFT and straight DSL, causing an avulsion of the
a surgical facility is highly recommended. eminence(s).