Page 599 - ONLINE PROCEEDING BOOK WSAVA 2017
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owner and clinician can under or overestimate lameness. This is a particular challenge when lameness is bilateral. With every stride each individual limb goes through a step cycle that comprises a stance (weight bearing) phase and a swing (non-weight bearing) phase. In
the average dog, each thoracic limb is responsible for approximately 30% of weight bearing when standing and each pelvic limb approximately 20%.
It is important to observe over a distance in excess of approximately  fteen metres away from and toward the observer and also from both sides. Video allows one to build up a data-bank of typical gait patterns and also allows playback in slow motion which can be very helpful to examine for subtle lameness. We have demonstrated in a recent study that dogs affected by DED generally stand with front feet externally rotated and with a more upright elbow stance than normal.
With regard to clinical examination, in dogs affected by MCD and MCompD,  exion and supination generally produces pain. In dogs with humeral intercondylar  ssure (HIF) pain can be evident on  exion and pronation or supination but is generally more evident on full extension of the elbow; the same is true of elbows affected by ununited anconeal process (UAP). Elbows affected by MCD and MCompD also generally manifest pain on deep pressure application to the medial aspect of the elbow over the insertion of the biceps brachialis complex on
the medial aspect of the ulna. Pain may in fact radiate proximally to the shoulder along the biceps brachii and can be mistaken for shoulder pain.
Radiography remains the mainstay of diagnostic interrogation. Radiography of the elbow joint should involve pulling the elbow away from the thorax so there are no superimposed soft tissues and attainment of a fully  exed and fully extended medio-lateral projection
is important. Cranio-caudal projections should be standardised such that the olecranon is always centralised relative to the humeral condyles. Oblique projections can occasionally be useful to skyline speci c features such as the epicondyles of the edge margin
of the medial coronoid process (MCP), but in reality, because most  ssure-fragmentation of the MCP occurs in the region of the radial incisure, which is axial and next to the radial head, the standard or cranio-caudal oblique projections rarely demonstrate fragmentation and CT scan is required.
Exposure factors are important and radiographic contrast in some cases makes the difference between success and failure regarding accurate diagnosis. Subtrochlear sclerosis (STS), which is an increased opaci cation of
the region of the ulna subjacent to the ulnar trochlear notch, is a really important early sentinel of DED and can sometimes be very dif cult to detect in early MCD. STS is likely in major part attributed to stress remodelling of the subchondral bone and is frequently present before
An Urban Experience
periarticular osteophytosis occurs. A properly positioned  exed or an extended medio-lateral radiographic projection of the elbow can make the difference between visibility or non-visibility of STS and of periarticular osteophytosis.
Elbow congruity is dif cult to appreciate radiographically unless it is of signi cant magnitude, there can be subtle incongruity that may be dynamic and present only in different positions of  exion and extension, or there can be appreciable incongruity that may only be evident on CT scan or on arthroscopic interrogation. The anconeal process is best appreciated on full  exion of the elbow in medio-lateral projection and this is particularly pertinent for interrogation of new bone formation (periarticular osteophytosis) which is an early sentinel of degenerative joint disease sequel to DED and also for appreciation of UAP.
OCD is often evident radiographically on cranio-caudal projections as subchondral “scalloping” remodelling
of the medial aspect of the humeral condyle. This can be confused with subchondral outline irregularity as a result of HUC that can be the consequence of the same supraphysiological overload precipitating MCD. This is generally termed MCompD. CT scan and arthroscopy are de nitive for elucidation of a primary humeral defect secondary to OCD by comparison with a secondary humeral defect subsequent to HUC.
Humeral intercondylar  ssure (HIF), which is the more correct terminology for what has hitherto been called incomplete ossi cation of the humeral condyle (IOHC), can involve a  ssure line between the medial and lateral aspect of the humeral condyle that may be oblique
and may not be apparent on direct cranio-caudal radiographic projections. In fact, the diagnosis may be missed when the HIF is subtle and early in the disease process. Later in the disease process, sclerosis of the margins of the  ssure plane creates greater visibility
of the lesion. Care must be taken to avoid over- interpretation of overlapping shadows of the cortical margins of the proximal olecranon (Mach Effect). CT interrogation is de nitive.
I personally no longer operate on any elbow disease without CT scan because our experience is such
that radiography regardless of positioning is not adequately speci c for interrogation of MCD, MCompD, determination of the extent of OCD or detecting ancillary pathologies.
Decision Making:
The odds are very low of being able to  nd exactly comparable patterns of elbow disease using our scoring scheme to facilitate exact comparison of treatment options. The most logical route for comparison of techniques in different dogs therefore is to group diseased elbows. For example, those with coronoid
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