Canine patellar luxation

Symptoms an owner can spot at home

• Intermittent skipping or 'hopping' on a hind leg for a few strides, then normal
• Occasional stretching of the leg backwards to 'reset' the knee
• Lameness that comes and goes without obvious cause
• Bow-legged or knock-kneed stance in severe grades
• Reluctance to jump or climb stairs

When to see a vet

• Any intermittent skipping gait, even if the dog seems fine most of the time
• Progressive worsening of lameness or new bilateral involvement
• Sudden non-weight-bearing lameness (may indicate concurrent CCL rupture, which is common in dogs with untreated grade III-IV luxation)

What it is

The patella normally rides in the trochlear groove at the end of the femur. Congenital conformational abnormalities, a shallow groove, a mis-aligned tibial tuberosity, or a rotational deformity of the femur or tibia, let the patella slip medially (most common in small breeds) or laterally (more common in large breeds). Trauma can also cause acute luxation but is far less common than the developmental form.

OFA and the Putnam grading system classify luxation from I (occasional luxation, spontaneous replacement) through IV (permanently luxated, cannot be reduced). Long-standing luxation deforms the growing skeleton and accelerates osteoarthritis. Roughly 15-20% of dogs with medial patellar luxation also rupture the CCL over time.

Treatment overview

This is editorial overview, not a treatment plan. Grade I and mild grade II cases are often managed conservatively with lean body condition, physical therapy, controlled exercise, and NSAID class analgesia for flares. Grade III and IV, and any grade with progressive lameness, are surgical, options include trochleoplasty (deepen the groove), tibial tuberosity transposition, and soft tissue reconstruction, often combined. Bilateral cases are typically staged surgically.

What owners can do

• Buy from breeders who OFA-grade patellas on both parents.
• Maintain lean body condition (BCS 4-5/9); every extra pound adds torque on a shallow groove.
• Provide traction on slippery floors (runners, non-slip mats) for small breeds.
• Structured muscle-building exercise (leash walks, swimming) protects the joint better than intermittent high-torque bursts.