Front Matter

Chapter 12 Disorders of the Canine Thoracic Limb: Diagnosis and Treatment 309

dogs present for progressive and intermittent
thoracic limb lameness at 5‐12 months of age
(Wind and Packard, 1986; Trostel et al., 2003b).
Physical exam findings include moderate to
severe weight‐bearing lameness (typically uni­
lateral), pain and crepitus on palpation and
PROM assessment of the elbow, and palpable
effusion, sometimes marked, of the lateral
aspect of the humeroulnar joint (Wind and
Packard, 1986; Trostel et al., 2003b).
Flexed lateral radiographs reveal the UAP
(Cook & Cook, 2009a) (Figure 12.19). A full
series of elbow radiographs of both limbs
should be obtained. Advanced imaging is not
necessary to diagnose UAP; however, CT and
arthroscopy may be performed to evaluate for
concurrent conditions as radiographs have
been shown to miss the concurrent diagnosis of
FCP in 50% of dogs with UAP (Meyer‐
Lindenberg et al., 2006).

Treatment

Several surgical treatment options have been
recommended for UAP (Krotscheck et al., 2000;
Pettitt et al., 2009). Osteotomy of the proximal
ulna is intended to relieve the excessive pres­
sure of the humeral condyle on the anconeus.
Performed alone, it has been shown to result in
radiographic union of the anconeal process in
12‐100% of dogs (Pettitt et al., 2009). Lag screw
fixation of the anconeal process has also been
recommended, alone and in combination with
proximal ulnar osteotomy (Krotscheck et al.,
2000; Pettitt et al., 2009). Recent studies suggest

that the best outcome is achieved with com­

bined lag screw fixation and proximal ulnar

osteotomy (Pettitt et al., 2009). If the diagnosis

of UAP is made after maturity and adequate

compression of the processes cannot be

achieved, excision of the anconeal process is

advised, if clinically warranted, and can result

in excellent long‐term function (Roy et al., 1994).

Postoperative care and rehabilitation is simi­

lar to that in the treatment of all elbow condi­

tions and is discussed elsewhere in this book.

Fragmented coronoid process

Pathophysiology

Fragmentation of the medial coronoid process

of the ulna is the most commonly diagnosed

developmental disorder of the elbow (Trostel

et  al., 2003a; Temwichitr et al., 2010). There is

substantial evidence to show a genetic com­

ponent to the disorder, with particular over­

representation in Labrador Retrievers, Bernese

Mountain Dogs, and Rottweilers (Trostel et al.,

2003a, 2003b; Temwichitr et al., 2010). The inci­

dence of FCP in Labradors is 18–50%

(Temwichitr et al., 2010). The exact mode of

inheritance has not been determined but there

is a strong familial association. A sex predilec­

tion has been reported with a male to female

ratio of between 2:1 and 3:1 (Trostel et al., 2003a).

FCP occurs bilaterally in 50–90% of dogs and

concurrent osteochondrosis has been reported

in up to 60% of cases (Trostel et al., 2003a).

The pathogenesis of FCP is not completely

understood (Danielson et al., 2006). Several

Figure 12.19 Radiographic image of an ununited anconeal process (arrow).