Page 231 - Canine Lameness

14.5 Elbow DysplasiaaIncongruity 203

(A) (C) (F)

(D) ELBOW REGION

(B) (E) (G)

Figure 14.4 IOHC examples: Patient I (A, B) was diagnosed on radiographs with IOHC based on observation of
a radiolucent line across the condylar area (black arrow); Patient II (C–E) was definitively diagnosed via CT as
illustrated in (D) (black arrow) which was recommended after noting (C) smooth periosteal proliferation of the
lateral supracondylar crest that is indicative of IOHC (white arrow); patients I and II underwent prophylactic
transcondylar lag screw fixation without complications; Patient III (F, G): upon initial presentation, (F) the
diagnosis of IOHC/HIF (black arrow) was missed and the condition progressed (G) to a Y-T fracture, illustrating
the importance of careful evaluation of radiographs/the importance of pursuing advanced imaging.

14.5 Elbow Dysplasia/Incongruity

Elbow dysplasia (ED), also termed “developmental elbow disease,” was defined as UAP, frag-
mented coronoid process (FCP), osteochondrosis dissecans (OCD), and incongruity by the
International Elbow Working Group over 25 years ago (Michelsen 2013). However, the terminol-
ogy has since changed particularly for FCP, and incongruity is now considered a contributing fea-
ture to the other three components of ED rather than an independent disease (Michelsen 2013).
The following two types of incongruities (Figure 14.5) have been most commonly proposed to play
a role in the pathophysiology of ED:
Radioulnar incongruity – this incongruity describes a mismatch between the radius and ulna
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resulting in a step at the radioulnar joint. If the radius is shorter than the ulna, excessive pressure
is placed on the coronoid process resulting in excessive loading and subsequent pathologic