Orthopaedics of the Knee – Patella Luxation

Presenter: Professor Stuart Carmichael BVMS MVM DSAO MRCVS, Professor of Veterinary Sciences, University of Surrey

As spatial awareness is not a particular strength of mine, I tend to refer all my orthopaedic surgeries to my colleagues, so it would have been very easy to avoid watching this webinar and choose something a ‘little more up my street’. However after watching last week’s webinar led by Professor Stuart Carmichael discussing patella luxation, I’m very glad I stepped out of my comfort zone to learn more about this common disease. After all, I still need to diagnose cases of patella luxation and help guide owners to make the right choices for their pet.

For those of you with more spatial awareness than myself (which would not be hard) Professor Carmichael discussed a selection of surgeries available to aid in the correction of patella luxation. These included the medial capsule release, deepening of the trochlear groove, tibial tuberosity transposition and lateral capsule overlap. The variety of techniques demonstrates the complexity of this progressive deformity, and why it is so important to treat these cases as early as possible to ensure the best outcome, especially in young growing animals.

The above mentioned surgical techniques were all discussed in depth by Professor Carmichael and are generally appropriate for the typical small breed dog or cat which suffers from the classic medial patella luxation. However there can be recurrence of patella luxation in larger breed dogs where these techniques have been used. This is due in part to a deformity of the femur which, if greater than 15 degrees, Professor Carmichael advises performing an osteotomy to correct, whether a varus or valgus. If less than five degrees, an osteotomy is not necessary and if somewhere between five and fifteen degrees a decision could be made either way.

Patella luxation in cats was also discussed within the webinar and Professor Carmichael explained that according to studies, 78% of cats will have patella instability (grade one patella luxation) which indicates this is probably normal in cats. However grade two and higher patella luxations are uncommon unless in specific breeds including Abyssinians, Devon Rexes, and British Whites.

I have only given a taster of the information delivered within this webinar and whether you are a budding orthopaedic surgeon or a bone-avoiding medic like myself, there is plenty of technical, practical and relevant advice to satisfy every type of vet.

The Stethoscope (MRCVS)



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