Page 750 - Adams and Stashak's Lameness in Horses, 7th Edition

716 Chapter 5

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A B
Figure 5.120. Cranioproximal to craniodistal (skyline) Arthroscopic removal is indicated in (A). Arthroscopy was attempted
projections showing a typical medial patellar fracture fragment in B, but an arthrotomy was necessary for removal.
(A; arrow) and a large displaced sagittal fracture (B; arrow).

can be successfully removed, and arthroscopy is
recommended. 18,30,59
Arthroscopy provides the best visualization of the
fractures, facilitating complete removal of fracture frag-
ments and exploration of the remainder of the joint
without the risk of incisional complications of an open
approach (Figure 5.121). The fragment can be dis-
59
sected from the patellar tendon with a large elevator or
a motorized soft tissue resector. If the fragment is large,
it can be divided with an osteotome or reduced with
motorized equipment. 59
Internal fixation should be considered for distracted
or displaced fractures with sizable fragments. The patel-
lar ligaments are the insertions of the quadriceps femo-
ris and biceps femoris muscles. The goals of repair of
larger articular fractures are integrity of the quadriceps
mechanism and prevention of OA. Successful internal
fixation of transverse distracted and longitudinally dis-
placed fractures of the patella has been reported. 2,21,41,47,77 Figure 5.121. Arthroscopic view of a medial patellar fragment.
Transverse fractures require firm fixation because of the The elevator is separating the patellar fragment from the soft tissue
tendency of the proximal segment to become distracted attachments.
by the pull of the quadriceps muscles, 21,47,77 although
perfect anatomic reduction may not be required in every ultrasonographic evaluation or more prolonged postop-
case. Tension band support is a good option for erative stall rest.
transverse patellar fractures. Large extra‐articular Internal fixation provides the most ideal set of cir-
47
fractures can be removed, but it may not be necessary in cumstances for a favorable outcome for displaced and
all cases. 106 distracted fractures. Recovery from anesthesia may be
the most critical point in the postoperative period.
Prognosis Horses with severely comminuted fractures are likely to
remain lame. Some of these may attain breeding sound-
The ultimate outcome depends upon retaining
quadriceps function and adequate congruent articular ness with prolonged stall rest. However, if the quadri-
ceps function is compromised or if severe OA develops,
surface; instability or persistent synovitis will result in euthanasia should be considered.
OA. Following conservative or surgical therapy, lame-
ness may persist for an undetermined period, while the
synovitis resolves and any patellar ligament desmitis or Fragmentation of the Distal Patella
enthesopathy heals. 23,59,79,80 Etiology
In a combined series of 19 horses from which articu-
lar medial fragments were removed, 16 returned to full FDP is an uncommon condition associated with pre-
work. 30,59 Failures occurred primarily because of preex- vious medial patellar desmotomy (MPD), 40,62,84,91,102,108
isting OA, luxated patella during recovery from anesthe- and not all horses with this condition have undergone
sia, and one unexplained ensuing OA. These failures surgery. Malalignment of the patella has been reported
62
may point to the value of thorough preoperative shortly after MPD, 8,90 and radiographically evident