Vet speak By Alison Laurie-Chalmers from Crown Vets in Inverness: Keeping your dog stepping on to the end of the road
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Pumpkin was a two-year-old Pomeranian dog brought in as over the past year it had been noted she was occasionally lame on one or both hind legs.
She was not particularly bothered by her lameness but her owner was noticing it more often, and she was occasionally seen hopping now on either back leg.
When she was younger it had been noted she had mild luxating patellae in both hind limbs. On this examination it was noted this was progressing and her grade of noted luxation had increased. So, it was advised she have surgery.
Patellar luxation is a displacement of the patella, the “kneecap,” to the side of the knee joint.
The patella is the kneecap, a small piece of bone that covers and protects the front of the stifle joint, the knee joint, on the back legs. In the thigh bone (the femur) there is a groove (the trochlea) in which the patella slides, and there are ligaments which hold the patella in place.
Patellar luxation often occurs if the trochlea is too shallow, and when the dog bends the knee the patella pops out of place. The patella can dislocate and this luxation therefore prevents the knee from bending and extending properly. Other conformational issues, such as a displaced patellar tendon and bowed hind limbs, can also add to the problem.
Luxating patella is most often a congenital disease due to an abnormal alignment of the bones and joints of the hind leg. It can affect any breed but more commonly toy and miniature breeds.The condition will sometimes only affect one leg but can be seen in both.
There may be a lameness and the foot may turn inward when the patella is out of place. Patellar luxation is usually characterised by an intermittent “skipping” or “hopping” where the dog will hold their affected leg up for several steps and then return to normal as the patella pops back in. When both legs are affected, you may see “bunny hopping”, as well as a stiff and awkward gait. In the early stages the condition may not cause too much discomfort but can occasionally lead to a more painful osteoarthritis.
Diagnosis is made by a physical examination. In some cases, X-rays may be required to fully assess the knee joint and surrounding conformation.
Depending on the ease of dislocating the patella and whether the patella returns to the groove spontaneously, the degree of luxation is graded from one to four.
Treatment is usually dependent on the severity of the patella’s condition. Grade one can often be left and monitored. With grade two, surgery can be considered, dependent on the frequency of the signs. Surgery is the recommended treatment for grades three and four, as this level can eventually cause the development of osteoarthritis over time.
The total recovery time after surgery is normally about eight to 10 weeks, with strict rest advised. Physiotherapy and hydrotherapy can also greatly assist recovery.
The outlook after correction is generally good to excellent, except for some very severe high-grade cases with concurrent osteoarthritic changes.
Thankfully Pumpkin recovered extremely well and was soon prancing along on her usual walks again, making friends with everybody.
• Alison Laurie-Chalmers is a senior consultant with Crown Vets in Inverness.
