PRACTICAL ARTHROSCOPY OF THE CANINE: An Introduction
Indiana State Veterinary Medical Association
January 26, 2006
Jeff Mayo, DVM
For the general practicing veterinarian interested in orthopedic joint disease, the
addition of arthroscopy to his or her practice will present a significant boost in diagnostic
capability, financial growth, and new enthusiasm in your chosen profession. Arthroscopic
evaluation of canine joints provides significant magnification beyond that of CT, MRI, and
open arthrotomy. With the illumination from a good light source, many aspects of a joint
can be viewed significantly better than conventional surgical approaches.
Arthroscopy carries with it relatively few disadvantages. Due to the small size, space,
and confinement within the joint, as well as complexity, it may pose some technical difficulty
depending on the operator and the patient. Expense may come into play with some
practitioners, although equipment requirements are generally less when compared with
Indications: The general indications for performing arthroscopy on a canine
patient include a history of lameness, stiffness, reluctance or difficulty arising in the morning,
avoiding stairs and jumping. On physical examination, the veterinarian should localize the
pain to a particular joint with findings of swelling, thickening of the joint, decreased range of
motion, and in particular a painful response to examination of a particular joint.
Radiographically, the practitioner should rule out cancer, long bone involvement, fractures,
panosteitis, and other conditions that might exclude the usefulness of arthroscopic
evaluation of a joint. Radiographic indications to perform arthroscopy include evidence of:
osteochondrosis dessicans, fragmented coronoid processes, ununited anconeal process,
intra-articular factures, increased joint fluid and capsular thickening, and periarticular
osteophytosis. Normal radiographic findings should not preclude an arthroscopic
examination of a particular joint if the history and physical findings are suggestive of joint
Equipment required: The basic equipment the general practicing veterinarian
should consider purchasing to perform arthroscopy in canines includes: an arthroscopic
telescope & sheath, camera, light source, and hand instruments. Alternative equipment
would include: an arthroscopic shaver, arthroscopic pump, and arthroscopy table or leg
support. In lieu of the arthroscopic pump, one can use the IV-pressure bag placed around a
bag of sterile saline during intra-articular infusion.
The arthroscopic telescope and sheath should be tailored to the desires of the
veterinarian. If the scope is only intended for arthroscopy, then one should consider a
shorter telescope and sheath (90-120 mm), as it is easier to manipulate inside the joint.
Arthroscopic telescopes and sheaths come with blunt trocars for intra-articular insertion that
are less likely to cause iatrogenic trauma. Widths for arthroscopic telescopes should be in the
1.9 – 2.4 mm range. The narrow telescopes are more flexible, more likely to break, and
produce a smaller image. However, they are also easier to enter the joint with and
manipulate. Excessive manipulation will result in potential trauma to the joint and the
telescope, so practice viewing the joint with minimal scope movement.
If the veterinarian wishes to obtain a more “universal” telescope and sheath,
consider purchase of a 2.7 mm telescope, approximately 170-190 mm in length. Depending
on the manufacturer of the telescope, a blunt trocar for intra-articular insertion may or not
be available. The longer length adds more of a challenge to the learning curve, but increases
the usefulness to the telescope in that it can be used for other procedures such as
rhinoscopy, laparoscopy, cystoscopy, and thoracoscopy.
A video camera is an essential component to successful arthroscopic procedures in
small animals. The telescopic view is magnified significantly on the video screen, and
prevents the examiner from having to bend over to place the naked-eye on the ocular piece.
Video cameras come in 1-CCD (charge-coupled device) and 3-CCD. Three CCD cameras
take superior pictures, but are not practical nor required for the general practitioner, as
images from 3-CCD cameras are more appropriate for teaching purposes and book
publishing. More important features of a good camera are: control of focus, magnification,
durability, ease of cleaning and use. Ideally, one should purchase a small camera with focus
control that can withstand some potential water soaking.
Light Sources: The light source is one of the more crucial pieces of equipment for
the arthroscopist. A low-powered light source will most certainly disappoint the veterinarian
once the telescope is in place and the image is poorly visualized. At the very minimum, a
150-watt halogen light source should provide enough light for most procedures. Poor
function results when one attempts to visualize an entire bladder in a large dog with a short
scope and a weak light source. The same is true for abdominal laparoscopy in large animals.
Improvement is achieved by utilizing a brighter light source such as Xenon. Most Xenon
light sources start around 175 watts. These light sources are much more expensive than
halogen, and replacement of the bulb can be expensive as well (upwards of $400-800 in
some cases). Attempts to “cut costs” by purchasing old Xenon lights or refurbished units
result in acquisition of large, heavy units that can compromise valuable space in the surgery
suit. Some older Xenon light sources can produce significant amounts of heat at the end of
the telescope, jeopardizing patient recovery. Refurbished Xenon light sources start around
$1,000, with new light sources starting around $5,000 and higher.
A metal halide light source is also available. This type of light should provide several
advantages: small power source, less expensive and longer lasting bulbs, cooler temperatures
at the end of the telescope, while maintaining a comparably brighter light in the optical area.
This particular light source also contains the camera power unit, and an insufflation unit, all
at an affordable price (MedRx™). This particular unit will contain the CPU (camera-power
unit), light source, and an insufflation pump at a competitive price to veterinarians.
Hand instruments: A limited number of hand instruments are needed to perform
adequate arthroscopy in the canine patient. At a minimum: 2.0 mm arthroscopic rongeur, 2.0
mm arthroscopic grasping forceps, a hook probe, a banana knife, 2-0 and 4-0 curettes, and
an exchange rod (switching stick). Most of what you would do as a beginning arthroscopist
could probably be performed with a 20 gauge 1-1 ½” hypodermic needle, a curved mosquito
hemostat, and a #11 scalpel blade.
It is important to locate the portals for instrument insertion in a proper and gentle
manner to avoid iatrogenic cartilage or skeletal damage to the joints. Portals can initially be
located using the 20 gauge needle and inserting into the jont, then aspirate joint fluid. When
inserting larger instruments into the joints, once the joint cavity is located with the needle, it
can be widened by inserting a #11 scalpel blade 3-4 mm maximum distance in the same
location and orientation as the needle that entered the joint. The hole can be further
expanded utilizing a mosquito forcep. Do NOT overdistend the hole else intra-articular fluid
will extravasate making arthroscopic examination very difficult even for the best
General considerations of all arthroscopic procedures include the following:
(1) Preoperative radiographs of the intended joint
(2) Consider placing towels on the floor underneath the working area to minimize
potential to slip or injure oneself on a wet floor
(3) Patient preparation & proper positioning
(4) Joint distension: can be distended with sLRS or bupivicaine @ 2 mg/kg
a. Consider submitting joint fluid for cytology
b. Why use sLRS instead of NSS?
(5) Telescopic portal: aka primary portal
(6) Egress portal: where the fluid flows out of the joint
(7) Operative portal: can use a trocar-cannula or insert instrument directly
Most joints can be adequately viewed through the arthroscope with minimal movements.
Joints should be held open using leverage from sandbags or the edge of the table. The
arthroscope and camera can be rotated intra-articularly to increase the viewing field by
simply rotating the light post and/or camera. Moving the telescope outward increases the
field of view, while moving the telescope inward will decrease the field of view.
Indications: chronic thoracic limb lameness, pain with flexion or extension of the shoulder
joint, pain on palpation of the shoulder joint, radiographic evidence such as intra-articular
swelling or an obvious OCD flap
Potential Arthroscopic Diagnoses: osteochondrosis dissecans, bicipital tenosynovitis,
shoulder instability, supraspinatus tendon damage, ligament damage, ununited caudal glenoid
tubercle, glenoid fracture, (any elbow condition), assessment of intra-articular fractures,
supraglenoid fracture, autoimmune synovitis
Potential Arthroscopic Procedures & Treatments: removal of OCD fragments, joint
mice, or fracture fragments, assisted reduction of joint fractures, RF-therapy of joint
instability, synovectomy, transaction of bicipital tendon
Patient Position & Preparation: Under general anesthesia, the patient is placed in lateral
recumbency with the affected limb up. A sandbag or other material is placed under the
elbow to act as a fulcrum during the procedure, as far proximal to the medial aspect of the
shoulder joint. The shoulder joint is clipped and prepared aseptically for the arthroscopic
procedure by wrapping the thoracic limb from the distal radius onward, the draping in the
shoulder joint area.
Arthroscopic Procedure: Shoulder
1. Joint Insufflation: In a sterile fashion, draw up 10-15 cc sLRS & attach a 1.5” needle;
attach the needle to a 3 cc syringe and insert just distal to tip of acromion process &
cranial (or caudal) to the acromion portion of the deltoideus muscle, obtain joint
fluid sample in lavender-top tube for cytology. Attach the syringe with sLRS and
distend the joint capsule. Can verify position of the needle in two ways:
o aspirate joint fluid prior to injection of sLRS (see above)
o release the tension on plunger once in joint; the syringe should refill with
sLRS easily indicating placement of the needle in the joint capsule
2. Using a #11 blade, make a SMALL stab incision in the same location and orientation
as the injection needle, approximately 3-4 mm proximodistal.
3. Place a blunt trocar into the arthroscopic sheath, close the portal(s) to flow. Hold the
proximal sheath in the palm of the hand, with the index finger along the distal shaft
of the telescope-sheath. Insert into the same location where the needle was placed.
4. Assuming the trocar/sheath is in the joint (how would you know?)
o ..withdraw the trocar, while maintaining the sheath in the joint
o ..insert the telescope (light post down) & twist the locking collar
o ..notch on telescope viewing screen → up
o ..attach the camera oriented upwards & lightly lock in place
o ..re-insufflate the joint (attach fluid line)
o ..begin arthroscopic viewing by moving telescope inward, outward, anterior
and posterior, while also moving the shoulder joint to help increase viewing
without placing too much torque on the telescope
5. Placement of the egress portal
o ..view craniolateral joint through the telescope in the area of biceps tendon
o ..using 20 g 1.5” needle, insert the needle medial or lateral to the biceps
tendon under direct vision so as to net lacerate the biceps tendon
o ..remove the needle and make a small stab incision with a #11 blade
o ..insert trocar into egress cannula, then pass cannula into joint
o ..remove trocar and attach IV line for drainage
6. Placement of the operative portal
o may consist of an operative cannula for insertion of instruments, or
instrument may be inserted directly into the joint
o difficult to place due to lack of bony landmarks
o located 1.5-2 cm caudal to the operative portal
o best visualized by first placing a 1 ½” needle under direct visualization into
o insert the trocar/cannula of the operative cannula into the joint under direct
visualization, remove the trocar, then insert the instrument
7. Recommended arthroscopic assessment of the shoulder
o With the light post pointing caudally, start cranially and assess the biceps
tendon and groove, and craniomedial joint compartment. By simply rotating
the light post dorsally, the viewing field will be down the bicipital groove.
Directly aiming the telescope at the medial joint capsule with the light post
up or down will give the practitioner a good view of the medial aspect of the
joint. Aiming the telescope caudally with the light post up will demonstrate
the caudal humeral head and joint capsule.
Indications: Chronic hindlimb lameness, joint compartment swelling, painful to palpation,
range of motion, positive sits test, decreased weight bearing, radiographic evidence, positive
drawer sign, tibial sag sign, meniscal click
Potential Arthroscopic Diagnoses: cranial cruciate tear, caudal cruciate tear, long digital
extensor tendon rupture, OCD, menisci tears, osteoarthritis, chondromalacia, autoimmune
synovitis, assessment of articular fractures
Potential Arthroscopic Procedures & Treatment: debridement of cruciate ligaments,
debridement/removal of torn menisci, medial meniscal release, removal of OCD fragments,
synovectomy, assisted reduction of intra-articular fractures
Patient Position and Preparation: Place patient in dorsal recumbency with the affected leg
hung for sterile draping; can either hang leg off table and manipulate with two people, or
place large sandbag under stifle to act as fulcrum.
Arthroscopic Procedure: Stifle
1. Draw up 15 cc sLRS into sterile syringe with 20 g 1” needle attached. With the stifle
in a flexed position, attach the needle to a 3 cc syringe and insert needle lateral to
patellar tendon ½ way between cranial pole of patella and tibial tuberosity, obtain a
joint fluid sample and place in a lavender-top tube. Attach the syringe with sLRS and
distend the joint. Releasing pressure on the plunger will confirm intra-articular
injection and not soft tissue or fat pad. Remove the needle.
2. Placement of the trocar/sheath into the joint: again at the same point, ½ between
the cranial pole of the patella and the tibial tuberosity, lateral to the patellar tendon,
insert the sheath with the stifle flexed. Place a blunt trocar into the arthroscopic
sheath; close the portal(s) to flow. Hold the proximal sheath in the palm of the hand,
with the index finger along the distal shaft of the telescope-sheath. Insert into the
same location where the needle was placed.
3. Once in the joint, extend the stifle and direct the sheath medially under the patella.
This position facilitates joint examination without the need for a shaver.
o penetrate medial to the quadriceps tendon and place the egress cannula; or
o place the telescope, camera, and re-insufflate the joint by attaching the fluid
line, proceed to next step
o alternative arthroscopic portal – can insert the trocar/sheath lateral to the
insertion of the patellar tendon, above the tibial plateau between the patellar
tendon and Gerdy’s tubercle. This position provides superior visualization of
the menisci, but requires arthroscopic shaving and removal of the fat pad.
4. Egress Portal Placement – the egress cannula can be placed utilizing the
trocar/cannula method (above), or can be placed separately. To insert the egress
cannula as a separate procedure, with the telescope attached, fluid insufflating the
o Insert a 20 g 1” needle along the distomedial aspect of the femur proximal to
the patella. You know you are in the joint when you get fluid back in the
o Insert a #11 blade slightly approximately 3-4 mm proximodistal into the
same point and at the same orientation to open the skin for insertion of the
o Insert the trocar into the egress cannula, and then insert the egress cannula
into the medial gutter of the stifle joint capsule. Remove the trocar.
o Attach a fluid line to the egress cannula and attach the other end of the line
to the end of an empty IV bag.
4. Operative portal placement – easiest of the joints discussed
o make small stab incision directly opposite of the primary portal
o Insert instrument directly, or…
o Insert trocar into instrument cannula, then insert cannula medial
parapatellar location directly opposite of primary portal
5. Recommended method for arthroscopic assessment of the stifle
o Starting with the telescope in the suprapatellar pouch and the stifle in
extension, withdraw telescope slowly to assess infrapatellar pouch;
with the light post aiming up, you will see the trochlear groove,
aiming the light post downward will demonstrate the patellar surface
o move the telescope medially to assess medial gutter; the laterally to
assess the lateral gutter; point the light source upward
o return the telescope back to the trochlear groove ventral to the
patella, then slowly withdraw the telescope while flexing the stifle to
allow the telescope to “drop” into the intercondylar notch. With the
light post downward, you are looking at the intercondylar notch and
cranial cruciate ligament; pointing the light post laterally increases
your view of the medial meniscus.
Indications: Chronic thoracic limb lameness, decreased range of motion, minimal weight
bearing, radiographic evidence, breed-susceptibility, normal shoulder arthroscopy
Potential Arthroscopic Diagnoses: fragmented medial coronoid process, OCD, ununited
anconeal process, osteoarthritis (collectively referred to as “elbow dysplasia”), assessment of
Potential Arthroscopic Procedures & Treatments: osseous fragment removal (OCD,
ununited anconeal process, fragmented medial coronoid process), synovectomy, assist in
intra-articular fracture repair
Patient Position & Preparation: The patient can be placed in lateral recumbency with the
affected limb down to use the edge of the table as a fulcrum. The limb must first be
prepped, by clipping as for an open arthrotomy, hanging the leg and draping it in a sterile
fashion. An alternative position is to place the patient in dorsal recumbency, hanging the
limb(s), prep as described above, then place a sandbag underneath the elbow to act as a
Arthroscopic Procedure: Elbow
1. Draw up 10-15 cc sLRS into sterile syringe with 20 g 1” needle attached. The needle
is placed adjacent or just proximal to the anconeal process and inserted distally and
axially into the joint. The sLRS is injected to distend the joint capsule visually and
palpably. Releasing pressure on the plunger will confirm intra-articular injection and
not soft tissue or fat pad. This needle can be left in the joint and establishes the
egress portal for the elbow and attached to an IV line, with the other end draining
into an empty IV bag on the floor.
2. Telescope portals for the elbow include: medial, craniolateral, and caudal. The most
common telescope portal is the medial portal. The medial portal is located 1-1.5 cm
directly distal to the tip of the medial epicondyle of the humerus. Some
arthroscopists also suggest moving 1 cm caudal from this location. The joint space
can be located by palpating the aforementioned landmarks while inserting a 20 gauge
needle and maintaining a downward force on the foot (valgus) to open the medial
joint capsule of the elbow. With the joint adequately distended, you will know you
have entered it when fluid escapes through the needle. Withdraw the needle and
make a small stab incision of 3-4 mm with a #11 blade proximodistally in the same
orientation as the needle was placed.
3. Place a blunt trocar into the arthroscopic sheath; close the portal(s) to flow. Hold the
proximal sheath in the palm of the hand, with the index finger along the distal shaft
of the telescope-sheath. Insert into the same location where the needle was placed.
The trocar-sheath can be inserted into the joint in the same location as the needle. Be
sure and apply adequate valgus force to the foot to open up the joint space. With the
joint adequately distended, you know you have the arthroscopic sheath intra-articular
when you remove the trocar and the sheath returns sLRS from the joint. If you are in
o …insert the telescope and lock the collar
o …attach the camera
o …attach the insufflation fluid line and open the portal
o …begin arthroscopic viewing
4. If an operative portal is required for the procedure;
o …insert a 20 g 1” needle into joint 1 cm cranial to telescope portal
o …remove needle, make stab incision using #11 blade
o …insert operative portal or instrument to be used
5. Recommended method for arthroscopic assessment of the elbow.
o The elbow joint is very narrow, and therefore movement
arthroscopically is limited. With proper technique, one should be able
to view the radial head, medial and lateral coronoids, anconeus,
medial humeral condyle, and trochlear notch. Viewing is greatly
facilitated by applying valgus pressure on the foot, and by pronating
and supinating the antebrachium.
Completion: Once any arthroscopic procedure is complete, every reasonable effort
should be made to evacuate fluid from the joint by opening portals, turning off fluid influx,
and moving the joint through its range of motion. All incisions should be closed in a routine
fashion. Postoperative bandaging of the joint is usually not necessary nor recommended.
Most patients should be walking as they were preoperatively within 1 week assuming
minimal-to-no surgical intervention accompanied the arthroscopic procedure.
Cleaning: Scopes used in arthroscopic procedures by the author are gas-sterilized,
along with the camera and cable attachments. Most of your rigid endoscopy equipment can
be adequately cleaned using commercially available enzymatic cleaners. All equipment should
be taken apart, the large debris hand scrubbed off with a soft cloth, and then soaked for 30
minutes in a commercially available enzymatic cleaner. Once clean, they should be
thoroughly dried prior to putting them back into storage to prevent corrosion.
Carts and Storage: You are going to spend a fair amount of money to get started in
rigid endoscopy. I highly recommend getting an adequately-sized endoscopy cart to hold
your equipment power units, electrical cords, and a CO2 tank. All hand instruments should
be stored in (1) original containers, (2) sterilization baskets, or (3) laid out flat in a rolling
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