Page 89 - Clinical Manual of Small Animal Endosurgery

Operative Arthroscopy 77

evidence of additional disease, prior to treating the humeral condylar
lesion. Typically, medial humeral osteochondral lesions are visible upon
insertion of the arthroscope. The caudoproximal extent of the lesion is
determined by craniodistal tilting of the arthroscope with craniodistal
rotation of the light post. The lesion is probed, if necessary, to identify
a free edge of cartilage that can be grasped with grasping forceps. A large
bite of cartilage is manoeuvred into the jaws of the grasping forceps and
the cartilage is gently elevated from underlying bone. The flap is removed
by gentle traction and tearing with judicious rotation of the grasping
forceps to lift the flap from its attachment. Occasionally, the flap comes
away as a single piece but more often multiple fragments are retrieved,
revealing a crater-like defect in the subchondral bone in the condyle.
Exchanging portals between the arthroscope and the instrument using a
switching stick is helpful to view the lesion in its entirety and to obtain
unimpeded access with the instruments. Remaining loose cartilage at
the edges of the lesion is removed with a small curette, creating vertical
edges. If denuded avascular bone lines the lesion without any evidence
of healing fibrocartilage, stimulation of bleeding and of healing tissue
may be indicated using the hand burr. Following debridement, the joint
is thoroughly flushed to remove osteochondral debris and closure is
routine. Prior to removal of the ingress/egress needle, intra-articular
analgesia is administered using a combination of ropivacaine and mor-
phine, as described above.

Arthroscopically assisted fixation of the ununited anconeal process
As for other manifestations of elbow dysplasia, objective outcome assess-
ment for treatment of ununited anconeal process lesions is currently
lacking. Present treatment recommendations advise re-attachment of the
ununited anconeal process in skeletally immature dogs if radiological
assessment indicates little evidence or only mild evidence of degenerative
joint disease. Re-attachment of an ununited anconeal process is thought
to provide joint stability and to decelerate progression of osteoarthritic
degeneration of the joint. Ulnar osteotomy is necessary to relieve stresses
acting on the anconeal process, facilitating fusion following fixation.
Arthroscopic assistance of fragment re-attachment enables the surgery
to be performed with less exposure to the joint compared to an open
arthrotomy technique and this may result in lowered patient morbidity.
The patient is positioned in dorsal recumbency and the affected limb
is supported in an abducted position, allowing the surgeon maximum
access to the caudomedial and caudal aspects of the elbow. Radiographs
should be studied carefully prior to and throughout the procedure to
assist accurate and correct implant placement. The anconeal fragment
is re-attached using a lagged 3.5 mm bone screw and an anti-rotation
arthrodesis wire, both of which are placed under arthroscopic guidance.
Following attachment of the anconeal process, an oblique proximal ulnar
osteotomy is performed in an open surgical manner using a caudal approach.