Legg-Calve-Perthes Disease: When a Puppy's Hip Bone Loses Its Blood Supply

During growth, the femoral head is fed by vessels running along the neck of the bone, and it has no meaningful alternative supply. If those vessels are interrupted, the bone tissue they serve dies. It does not hurt at first, because dead bone has no nerves. Pain begins when the weakened structure starts to collapse under the puppy's weight and the joint surface deforms.

That sequence produces three features that together are close to diagnostic in a toy breed.

The first is timing. Onset clusters roughly between five and eight months, in the middle of the growth period. A limp that begins in that window in a Papillon deserves radiographs rather than a fortnight of rest.

The second is that it is almost always one sided. Bilateral cases exist but are the minority, so a puppy favouring the same leg every day, week after week, fits.

The third is muscle wasting. A puppy that has been offloading one hind leg for a month loses bulk in that thigh, and the difference becomes striking. Because a Papillon's long silky coat conceals body contours, you find this with your hands rather than your eyes: wrap a palm around each thigh and compare.

Progression separates it from a slipping kneecap, which comes and goes. This gets worse.

This is one of the more satisfying orthopaedic conditions in small dogs, because the standard operation converts a painful joint into a working one.

If you think your Papillon has legg-calvé-perthes disease, the plan is three steps: write down what you have seen and when it started, book a veterinary appointment rather than waiting for the next flare, and take video of the behaviour or symptom before you go — the thing you are worried about rarely happens in the consulting room. Screening in the parents covers patellar luxation, progressive retinal atrophy, dental disease.

What the vet visit should produce is a diagnosis and a written plan, not just reassurance: what is being ruled out, what the monitoring interval is, and which signs mean you come back sooner. Ask what the treatment costs across a year rather than per visit, because that is the number that decides whether you are managing this condition or reacting to it.

Between appointments, keep a short log — dates, what you saw, what changed. It is the single most useful thing an owner brings to a follow-up, and for legg-calvé-perthes disease it is often what separates a clear pattern from a guess.