About Rata Procedures Refer a case Resources Feature cases Contact FAQ's
Patella Luxation (Feline)
Feline Patella Lux
Turner Bone Boris 11605345 Stifle Stifle Cranio Caudal 17 07 2017 09 40 32 566

Information about the procedure for referring vets.

The Surgery
The patella (kneecap) normally sits in a groove at the end of the femur, called the trochlea. It tracks within the trochlea when the sti e (knee) is exed and extended. Patellar luxation is displacement of the patella out of
the trochlea, and can range in severity from a Grade
1, where the patella pops in and out of the trochlea
with manipulation, to a Grade 4 where the patella is permanently displaced out of the trochlea. This most commonly occurs to the inside (medial) of the sti e but can also occur to the outside (lateral) of the sti e. It is
a developmental condition which means it develops as the cat grows and is caused by poor alignment of the hip, quadriceps muscles and stife. Surgery is indicated in any cat that shows clinical signs as a result of the condition. The condition is commonly bilateral (affecting both legs) so often, the cat shows a crouched hind limb gait which can mimic hip or neurological disease. The earlier the surgery is done, the better the outcome as there will be less damage to the joint surfaces (articular cartilage).
Cats with MPL vary from dogs in a number of ways:
• Their patella is more mobile naturally, so this can often be misdiagnosed as a Grade 1 luxation.
• They don’t commonly have the same skeletal deformities of the tibia and femur found in dogs with patellar luxation, so rarely need an osteotomy (cutting of the bone).
• Their patella is wider than in dogs.
The Procedure
• Trochleoplasty: This is widening and deepening of the trochlea and involves lifting the articular (joint) cartilage surface by cutting a wedge or rectangular block, removing the required amount of underlying bone, and replacing the overlying cartilage block. This is usually carried out in every case of feline MPL
• Soft tissue stabilisation: This involves tightening (imbrication) of the lateral (outside) tissue next to the patella as well as release of any tight medial (inside) tissue. It also involves placing an absorbable suture sling around the patella which is anchored to a small bone behind the femur (fabella), which holds the patella in place whilst the soft tissue heals.
• TTT/TCT (Tibial Tuberosity/Crest Transposition): The portion of the bone that the patella tendon attaches to is cut with a bone saw, and moved laterally to align the thigh muscles with the sti e (allowing the patella to track correctly). It is then secured in its new position with bone pins, and in some cases orthopaedic wire. This is rarely required in cats.