Moderate severity

Luxating Patella (Slipping Kneecap)

A kneecap that slips out of its normal groove, causing an intermittent skip or hop in a back leg; often mild in cats but sometimes needing surgery.

⚠️ Common symptoms

An occasional "skip" or hop in a hind leg during walking or runningBriefly holding a back leg up, then returning to normalA leg that seems to lock or stick momentarily before freeingReluctance to jump as high as before, or landing awkwardlyStiffness or reduced activity in more advanced or arthritic casesIn many cats, few obvious signs at all until it is found on examination

A luxating patella means a "slipping kneecap": the small bone at the front of the knee pops out of the shallow groove it should sit in, then usually slides back. In cats it is often a milder, more incidental problem than in dogs, and many affected cats live comfortably with it, but it is worth understanding because the tell-tale skipping gait can otherwise be baffling to owners.

The classic sign is an intermittent hop or skip in a back leg: the cat is walking or running normally, the kneecap briefly slips, the leg locks or is carried for a stride or two, and then everything returns to normal as it slots back into place. Because it comes and goes, and because cats are so good at compensating, it is frequently picked up by a vet feeling the knee during a routine examination rather than reported as obvious lameness. Vets grade the condition from mild, where the kneecap only luxates when pressed, through to severe, where it sits permanently out of place.

Most feline cases are developmental, related to the shape of the groove and the alignment of the leg, with certain breeds somewhat predisposed, though injury can also be responsible. Treatment is matched to how much trouble it causes. Mild cases are typically managed conservatively — weight control, sensible exercise, monitoring and pain relief if needed — while cases causing ongoing lameness, discomfort or early arthritis may be improved with surgery to deepen the groove and stabilise the kneecap. Keeping a cat slim and active is the single most useful thing an owner can do, and any persistent skip or held-up hind leg is worth having a vet assess so the joint can be protected over the long term.

🔍 Causes

The patella (kneecap) normally glides in a groove at the end of the thigh bone. A luxating patella occurs when it slips out of this groove, usually to the inside of the leg. Most cases are developmental, linked to a groove that is too shallow or to slight misalignment of the limb, and some breeds such as the Abyssinian and Devon Rex appear more prone to it. It can also follow an injury to the knee. Being overweight adds strain to the joint and can make signs worse.

🛡 Prevention

The tendency is largely built-in and cannot always be prevented, but its impact can be reduced. Keeping a cat at a healthy weight takes load off the knees, and safe, regular activity helps maintain the muscle that stabilises the joint. Responsible breeding away from affected lines lowers the inherited risk. Early veterinary assessment of any skipping gait allows the problem to be graded and managed before arthritis sets in.

💊 Treatment

Management depends on severity. Many mild cases in cats need no more than keeping the cat lean, maintaining gentle activity and monitoring, sometimes with joint supplements or anti-inflammatory pain relief during flare-ups. More severe or painful cases, or those causing persistent lameness and arthritis, may be corrected surgically to deepen the groove and realign the kneecap. A vet grades the looseness to decide whether surgery is warranted.

When to see a vet: Book a non-urgent veterinary check if you notice your cat intermittently skipping, hopping or holding up a hind leg, even briefly. Seek advice sooner if a leg is held up persistently, the cat seems in pain, or lameness is worsening, as more severe luxation may benefit from surgery before secondary arthritis develops.

⚕️ Medical disclaimer

  • This information is educational only and is not a substitute for veterinary advice.
  • Symptoms overlap between conditions — only a vet can diagnose accurately.
  • Never withhold treatment or self-medicate based on information found online.
  • When in doubt, call your vet. Early intervention almost always leads to better outcomes.

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