The lateral parapatellar approach is most commonly used.
This approach provides adequate visualization of the articular surface of the patella and the patellar ligament. The implants are introduced from the cranial aspect of the patella, outside the stifle joint.
Key anatomic landmarks to be identified prior to the surgical approach include:
Lateral aspect of the femoral trochlea
Long digital extensor tendon
Depending on the fracture type, these landmarks may be displaced, particularly patellar fragments. Care should be taken to identify them not to damage them during the approach.
3. Skin incision
An incision is made from the distal third of the femur to the proximal tibia, parallel and just lateral to the patellar tendon distally.
The subcutaneous tissues are incised along the same line and retracted. The lateral fascia is incised cranial to the biceps muscle. The biceps fascia is retracted caudally. Separation between the biceps fascia and the vastus lateralis muscle is necessary proximally. Blood vessels in this region may need to be cauterized or ligated.
A stab incision is made into the joint capsule 2-3 mm lateral to the patella. The incision is extended proximally to the vastus lateralis and distally to the tibial tubercle using scissors, making sure that sufficient tissues are left adjacent to the patella and patellar tendon for closure of the joint capsule. Great care must be taken to protect the long digital extensor tendon lying inside the joint, just lateral to the incision site.
Pearl: Grasp and tension the joint capsule with forceps prior to the stab incision to avoid damaging the long digital extensor tendon and the femoral trochlea.
With the stifle in extension the articular surface of the patella is exposed and inspected.
The joint capsule is closed using absorbable sutures. The biceps fascia is closed in an appositional pattern. Subcutis and skin are routinely closed.