TL;DR: A swollen, warm knee joint in dogs indicates localized inflammation from injuries like a CCL tear or infection and requires a veterinary examination within 24 to 48 hours.
What does a swollen, warm knee joint mean for my dog?
- Localized inflammation responding to an internal injury or an immune response.
- Cranial Cruciate Ligament (CCL) tear, which is similar to an ACL injury in humans.
- Flare-up of osteoarthritis.
- Septic arthritis (infection within the joint) or a systemic inflammatory condition.
How quickly should I take my dog to the vet for a swollen knee?
- Schedule a veterinary exam within 24 to 48 hours for most cases.
- Seek immediate emergency care if the swelling is accompanied by a complete inability to bear weight, high fever, or profound lethargy.
- Prompt attention helps prevent secondary damage to the joint and provides necessary pain relief.
How can a photo or video help the vet triage my dog's knee injury?
- Allows the triage nurse to see the scale of the swelling and the specific location of the inflammation.
- Comparing the affected leg to the healthy leg in one frame helps the vet assess severity.
- A video of your dog walking helps the vet analyze their gait to identify joint instability.
Clinical Context (Merck Veterinary Manual)
In dogs, a swollen knee joint that is warm to the touch may indicate several potential causes requiring veterinary triage. Septic arthritis, often caused by bacterial agents like staphylococci or streptococci, can result from hematogenous spread of infection. Polyarthritis, involving inflammation of multiple joints, can be infectious or noninfectious (immune-mediated), presenting with fever, lameness, swollen joints, and lethargy. Joint trauma, such as cranial cruciate ligament rupture, is another common cause, potentially linked to degeneration or immune-mediated diseases. Radiography is essential to assess joint effusion, soft tissue swelling, and periosteal reaction to aid in diagnosis.
Chapter: Orthopedics, Immunology
Source: The Merck Veterinary Manual, 11th Edition (Page 1198)