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8

Diagnostic Joint Anesthesia

1
Bryan T. Torres and Felix Michael Duerr 2
1 Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
2 Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA

8.1 Introduction

The use of intra‐articular anesthetic agents to aid in the diagnosis of lameness has been long estab-
lished in equine veterinary medicine (Dyson 1986). However, within the past few years, there has
been an increased interest in employing diagnostic joint anesthesia (DJA) or “joint blocks” as a
diagnostic tool in small animals to aid clinicians in pinpointing the source of lameness (Van Vynckt
et al. 2012a). Principles of DJA are outlined in Box 8.1.

8.2 Patient Selection

In general, any dog with an unidentifiable source of lameness may benefit from DJA. Particularly
if advanced diagnostics (such as CT/MRI) are not readily available, DJA may be helpful to justify
that such diagnostics are indicated. If DJA results in a positive response, it allows the clinician to
determine the injected joint as the most likely source of lameness. If DJA results in a negative
response, it places other differential diagnoses higher on the list. As is true in horses, DJA aims to
identify the joint responsible for a lameness rather than provide a specific diagnosis. This approach
can be clinically useful in the following scenarios:
Patients presenting with a lameness that is thought to be joint related, but the physical exam and
●
available diagnostics are not definitive (e.g. a dog with suspected elbow dysplasia that shows no
pain on examination and radiographs only show minor/no abnormalities). In this scenario, a
positive DJA result (of the elbow joint) may aid to confirm the elbow as the source of lameness.
Patients presenting with a lameness and multiple joints show abnormalities (e.g. a dog with
●
shoulder and elbow osteoarthritis). In this scenario, a positive DJA result (of the elbow or shoul-
der joint) may aid to confirm the elbow or shoulder as the source of lameness.
Patients presenting with a lameness and multiple detected abnormalities (e.g. a dog with shoul-
●
der osteoarthritis and possible axillary pain). In this scenario, a negative DJA result (of the
shoulder joint) may aid to confirm that further diagnostics (such as MRI) investigating a possible
neurologic reason (such as brachial plexus tumor) for the lameness is indicated. On the other
hand, a positive result would confirm the shoulder as the source of lameness.

Canine Lameness, First Edition. Edited by Felix Michael Duerr.
© 2020 John Wiley & Sons, Inc. Published 2020 by John Wiley & Sons, Inc.
Companion website: www.wiley.com/go/duerr/lameness