The arthrotomy and creating the graft
Approach the stifle joint via a lateral parapatellar incision.
Subcutaneous connective tissue is cleared from the area and tensor fascia lata.
Use of dry swabs/gauze to grasp and tear back these tissues is a useful shortcut.
Separate the lateral third of the straight patella ligament from tibial tubercle to
Continue the incision proximally around the patella, leaving sufficient fibrous
tissue attached to the patella to allow re-suturing.
Extend the incision up into the tensor fascia lata following the direction of the
fibres. Remember the graft should be of fascia only so stay cranial to the border
of the biceps femoris. The graft will be approximately 8 to 20mm wide depending
on the size of dog.
Harvesting a long graft will allow reattachment of the free end back onto the
straight patella ligament but will add time to the closure. Taking a shorter graft
requires that the free end must be attached in the fabella region (see later).
The lateral border of the graft is created by incising along the lateral border of
the straight patella ligament. As the incision approaches the patella double the
width of the graft. The transitional area between patella ligament and tensor
fascia lata is thought to be a weak point. The incision is continued up into the
tensor fascia lata running parallel to the initial incision staying just cranial to the
biceps femoris muscle mass. As a general rule the fascia lata portion has double
the width of the patella ligament portion.
From the proximal end of the parallel incision the graft is freed along its length
down to the insertion on the tibial tubercle. Any adherent connective tissue is
The joint capsule is now incised again leaving enough tissue on the patella for re-
Examination of the medial meniscus
The patella is dislocated medially and the joint examined.
Particular attention is paid to the medial meniscus which is prone to damage
particularly in large dogs with long standing injuries.
Exposure of the medial meniscus is difficult and is achieved with the help of a
hohman retractor or better still a dedicated stifle distractor.
Damaged meniscus is grasped and excised using ligament clamps or artery
forceps and a No 11 blade or meniscus knife.
Passing the graft passer and the graft
The lateral fabella is exposed using a hohman retractor 18mm with a short tip.
The tip is forced through the joint capsule at the level of the fabella and pushed
caudal to the femoral condyle. The handle is pushed caudally forcing the muscle
and fascia away from the fabella. Failure to adequately expose the fabella is a
common cause of difficulty. The muscles caudal to the fabella tend to direct the
tip of the graft passer into the proximal tibia.
A stab incision is made into the femoro-fabellar ligament to facilitate passage of
the graft passer. In some difficult cases the graft does not have to pass through
this ligament but must a least exit close to the caudal border of the fabella.
The graft passer is directed behind the lateral condyle into the inter-condylar
space to exit lateral to the caudal cruciate ligament.
It is this part of the procedure which causes surgeons most difficulty. The
following observations may be helpful.
Usually the problem is that the tip of the graft passer is hitting the tibia
rather than passing through the joint space. Appropriate retraction of the caudal
muscle mass will help. It is important to think three dimensionally and try to
visualise where the tip of the graft passer is at any one time.
The graft passer does not need great force to get through. If the passer
bends you are getting frustrated and pushing too hard!
If repeated attempts fail try reversing the graft passer and passing it
through cranial to caudal aiming for the fabella. Where it exits close to but not
necessarily through the femoro-fabellar ligament is a good starting point for an
attempt in the normal direction.
If further efforts fail pass a piece of nylon though the eye of the passer
pass it cranial to caudal and use the nylon to pull the graft through.
Once the passer is though pass 10 to 20mm of the free end of the graft though the
slot in the passer. Passing more than half of the graft through will result in
breakage of the graft.
The graft is pulled through the joint by rotating the graft passer out of the
Attaching the graft
The free end of the graft is grasped using artery forceps and pulled across the
femoro-fabellar ligament towards the tibial tubercle and attached by one of the
Traditionally the graft was sutured onto the femoro-fabellar ligament
using stitches of nylon or long term absorbable.
As above but in addition the graft is harvested longer and the free end
sutured onto the distal straight patella ligament, thereby creating a 'sling' effect
around the lateral condyle.
A spiky ligament staple is placed over the graft into the femur cranial to
The graft may also be attached to the lateral condyle using a screw and
The parapatellar incision is closed in layers using absorbable sutures.
Post operative treatment
Ideally a Robert Jones bandage is applied for the first 5 to 7 days.
Leash exercise only for the next 10 weeks.
The graft initially loses strength for the first six weeks and then gradually gains
strength. It is important that the graft is not overstressed during this weak stage.
Some surgeons like to protect the graft using a lateral suture from fabella to
tibial tubercle. This suture is strong immediately post operatively and eventually
fails once protective fibrosis and graft come up to strength.