Page 152 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.4 The forelimb 127

VetBooks.ir direct palpation over the proximodorsal articulation Diagnosis
P1 and P2 fractures are usually visible on standard
of the proximal phalanx. Incomplete P1 fractures
usually present with moderate to marked lameness
the proximodorsal aspect of P1 may be visible and
with effusion/pain of the metacarpo/ tarsophalangeal radiographic projections. Periosteal new bone on
joint. Complete/comminuted P1 fractures usually subchondral sclerosis and cyst-like lesions have been
present as severe lameness referable to the proximal described associated with short, incomplete P1 frac-
phalanx with instability. tures. Sagittal and comminuted P1 and P2 fractures
P2 fractures generally occur due to an acute trau- require full radiographic assessment to describe the
matic incident. Moderate to severe lameness is com- configuration. CT may be helpful if reconstruction
monly encountered. Due to the location of most of is considered, particularly in inspecting the articular
P2 within the hoof capsule, instability and crepitus is margins for hidden fragments.
variable and in cases of uniaxial eminence fractures, MRI has been used to describe prodromal fracture-
stability of the pastern joint may not be compro- like changes in P1 and focal increased radiopharma-
mised. Osteochondral fragmentation may be found ceutical uptake in the dorsoproximal aspect of P1 has
on survey/pre-purchase radiographs and not nec- been documented using nuclear scintigraphy.
essarily associated with lameness. When lameness
is present, localising signs may be mild and anal- Management
gesia of the pastern joint is recommended to prove Short, incomplete P1 fractures can be managed con-
significance. servatively but the use of internal fixation may result
in improved bone healing in a more predictable
Differential diagnosis rehabilitation time. Incomplete sagittal P1 fractures
Distal metacarpal/metatarsal fracture; fracture of have been repaired in the standing, sedated horse,
the proximal sesamoid bones; subluxation (pastern/ reducing the risk associated with general anaes-
fetlock); synovial sepsis; severe soft-tissue injury; thesia. Complete sagittal P1 fractures are usually
subsolar abscessation. amenable to internal fixation (Figs. 1.122, 1.123).

1.222 1.223

Figs. 1.222, 1.223 A complete,
biarticular P1 fracture with mild
displacement prior to repair (1.222)
and following the placement of
three lag screws placed through
stab incisions (1.223).