Page 75 - Clinical Manual of Small Animal Endosurgery

Diagnostic Arthroscopy 63

Investigative arthroscopy of the carpus and tarsus

Arthroscopic investigation and treatment of the small joints in dogs is
less well established compared to the experience in the larger joints. In
the carpus, investigations of arthropathies, intra-articular fractures,
unexplained pain, neoplastic processes and joint instability are all current
indications for investigative arthroscopy. For investigation of the carpus,
the patient is positioned either in sternal recumbency or in dorsal recum-
bency with the limb drawn caudally, both positions giving ready access
to the dorsal aspect of the carpus. Both a dorsolateral and a dorsomedial
portal to the antebrachiocarpal joint are generally employed enabling
both sides of the joint to be viewed. The dorsolateral arthroscope portal
is located between the digital extensor tendons and the dorsomedial
portal is located medial to the axial midline of the carpus, midway
between the distal radial articular surface and the radial carpal bone.
These two portals are used interchangeably as the egress/instrument
portal and the arthroscope portal enabling examination of both the
medial and the lateral components of the antebrachiocarpal joint. Inspec-
tion of intra-articular pathologies follows the normal principles of
arthroscopic investigation, using joint-specific charting and performing
instrumented evaluation of soft tissues and of articular cartilage to fully
evaluate functional integrity of tissues.
Indications for arthroscopic investigation of the tarsus are similar to
those of the carpus, including investigations of arthropathies, intra-
articular fractures, unexplained pain, joint instability, neoplastic proc-
esses and investigation of osteochondrosis. Arthroscopic investigation of
the entire tarsus requires the use of two dorsal portals and two plantar
portals to fully evaluate the joint space but investigation for synovial
biopsy or investigation of lesions localised to one side of the joint (as
determined by diagnostic work-up) require only one or two portals.
Patient positioning is important to ensure that the hind limb can be
manipulated in all planes during the procedure because the tarsal joint
space is small and obtaining a good view of the area of interest can be
challenging. It is useful to position the patient with the distal limb
hanging from the edge of the operating table to maximise excursions
during arthroscopy. Arthroscopic inspection and evaluation are assisted
by blunt probing to evaluate soft tissues and cartilage and biopsy/
grasping forceps are invaluable for tissue sampling.

Further reading

Åkerblom, S. and Sjöström, L. (2006) Villonodular synovitis in the dog: a report
of four cases. Veterinary and Comparative Orthopaedics and Traumatology
19, 87–92.
Åkerblom, S. and Sjöström, L. (2007) Evaluation of clinical, radiographical
and cytological findings compared to arthroscopic findings in shoulder joint