Patella Luxation

 

Luxated patellas are a congenital condition. The actual luxation may not be present at birth, but the structural changes which lead to luxation are present. Most researchers believe luxated patellas to be heritable, though the exact mode of inheritance is not known. Researchers have suggested that due to the high risk factor in small breeds, breeding trials or retrospective pedigree analyses should be undertaken by national breed clubs to answer some of these questions .

The stifle is a complicated joint which is the anatomical equivalent of the human knee. The three major components involved in luxating patellas are the femur (thigh bone), patella (knee cap), and tibia (calf or second thigh). In a normal stifle, the femur and tibia are lined up so that the patella rests in a groove (trochlea) on the femur, and its attachment (the patellar tendon) is on the tibia directly below the trochlea.

The function of the patella is to protect the large tendon of the quadriceps (thigh) muscle as it rides over the front of the femur while the quadriceps is used to extend (straighten) the stifle joint. Placing your hand on your own patella (knee cap) while flexing and extending your stifle (knee) will allow you to feel the normal movement of the patella as it glides up and down in the trochlea.

Luxation (dislocation) of the patella occurs when these structures are not in proper alignment. Luxation in small breeds most frequently occurs medially (to the inside of the leg). The tibia is rotated inward which allows the patella to luxate (slip out of its groove) and ride on the inner surface of the femur. While the patella is luxated, the quadriceps is unable to properly extend the stifle, resulting in an abnormal gait or lameness. In addition, the smooth surface of the patella is damaged by contact with the femur, rather than the smooth articular (joint) cartilage present in the trochlea.

With time this rubbing will result in degenerative joint disease (arthritis). Furthermore, while the patella is luxated, the quadriceps puts a rotational force on the tibia, which over time will increase the rotation of the tibia, thereby increasing the severity of the problem. The additional strain caused by the malformation of the bones may also lead to later ligament ruptures. Many individuals are affected bilaterally (both legs).

Signs of luxation may appear as early as weaning or may go undetected until later in life. Signs include intermittent rear leg lameness, often shifting from one leg to the other, and an inability to fully extend the stifle. The leg may carried for variable periods of time. Early in the course of the disease, or in mildly affected animals, a hopping or skipping action occurs. This is due to the patella luxating while the dog is moving and by giving an extra hop or skip the dog extends its stifle and is often able to replace the patella until the next luxation, when the cycle repeats.

Luxating patella is a condition that has been seen in the Cesky Terrier. For this reason, the Cesky Terrier Club has introduced a testing scheme for the breed. The relevant form can be downloaded from the website or is obtainable from the Club Secretary or Breed Health Co-ordinator.

A special trip to the vet is not necessary, but when you have to go please take all the relevant paperwork and ask for the dog’s patellas to be checked at the same time. This way there should only be a nominal charge.

You can use any vet of your choice. They will check the details of the dog against its Kennel Club registration document and confirm the microchip. Following examination of the dog using the Putnam (1968) Scoring System, the vet should complete and sign the form.

A copy of the fully completed form, signed by both the owner and the examining vet should be sent to the Breed Health Co-ordinator.

There is no anaesthesia or x-ray involved – just three easy steps:

  • Have your dog microchipped, if not already done.
  • Take the form and the KC registration document with you on your next visit to the vet.
  • Return the completed form (or a copy) to the Breed Health Co-ordinator.

The Club’s aim is to have as many Cesky Terriers as possible screened using this scheme, but certainly dogs used in breeding programmes should be tested prior to mating. Dogs can be tested from 12 months of age onward with no maximum age limit, although the optimum time is between 12 months and 2 years old.

A copy of the form should be sent to the Breed Health Co-ordinator,

Wendy Tobijanski

Hillcrest, Rhyn Lane, St Martina, Oswestry SY10 7AY

or email

Download Patella Luxation Form

Tested Dogs

Name

Score

DoB Scored
Dogs:      
Ace The Knight of Lulu Island

0 – 0

12/11/10 22/2/12
Duffy du Champ d’Eole avec Polede

0 – 0

25/1/08 17/11/09
Komidion Nickelodeon avec Dajaces

0 – 0

29/06/10 6/2/12
Oneva Eduard Malsville

0 – 0

19/10/07 7/4/10
Polede Lforluka

0 – 0

20/11/05 17/11/09
Ridley Tomas

0 – 0

14/6/10 26/10/11
Vandell Taste of Honey at Lynjame

0 – 0

6/10/07 19/4/10
       
Bitches:      
Alaska Day Break

1 – 0

28/9/06 4/7/09
Cassencarrie Czechout of Veltrusy

3 – 1

26/1/96 8/6/09
E’french Connection du Champ d’Eole

0 – 0

28/7/09 23/8/11
Emily Day Break

0 – 0

11/10/10 23/12/11
Gloria Kvitko

0 – 1

14/6/01 22/7/10
Ridley Pamatka

0 – 0

9/9/07 17/6/09
 Posted by at 8:32 pm