Summary
Elbow incongruity is the term to describe bad alignment of the joint surfaces of the
elbow. Two features illustrate incongruity of the elbow: an abnormal shape of the
ulnar trochlear notch and a step between the radius and ulna, caused by either a short
radius or a short ulna. It has been suggested that both an elliptical notch, and a
step, can cause increased local pressure within the joint, resulting in loose fragments
at different locations: ununited anconeal process (UAP), fragmented coronoid process
(FCP), osteochondritis dissecans of the humeral condyle (OCD). These lesions are grouped
under the term ‘elbow dysplasia’ and are the most frequent causes of front leg lameness
in the dog. Although several radiographic features to diagnose incongruity have been
described, the ‘scoring’ of incongruity is subjective because there is currently no
objective method to measure the degree of incongruity. Because superimposition is
avoided, CT is suggested as a standard technique to measure incongruity. Arthroscopy
on the other hand, allows the direct visualisation of the intra-articular structures
and their abnormalities. Information on both techniques are still relatively new.
Several surgical techniques have been proposed to restore joint congruity; the one
most frequently used is an ulnar osteotomy. But because of possible complications,
other techniques are being developed. Reports evaluating the results of the different
techniques are not yet available.
Keywords
Elbow incongruity - literature - scoring - diagnosis - dysplasia