Why is my dog's back leg stiff, swollen, and held up after resting?

What you're describing sounds like a condition called a luxating patella. This is when the knee cap slides in and out of its groove. This condition overtime can lead to arthritis and potential he predispose a dog to tearing a ligament in the knee. Your veterinarian maybe to do an orthopedic exam and tell you if this is the case.

If one leg is harder to extend it could indicate early arthritis or it may simply be that she is holding it back tighter. I wouldn't worry if she is moving about fine, but you could always have the vet check it out. It might be worth starting her on a joint supplement with glucosamine and chondroitin.

She could have some arthritis in her hips, a loose knee cap, or a strain/sprain. You could have your vet examine her to determine the cause. Your vet can take an X-ray, if needed, to help diagnose and the determine the best way to treat. She may need an anti-inflammatory to treat.

It may be. She may have a soft tissue injury or some slight swelling at the knee which is causing the patella to luxate even though it has not been a problem in the past. Your veterinarian can most likely determine if that is the case by a physical exam. If her patella is loose and moving around, it is usually pretty easy to detect.

Hello and thank you for contacting Petco Pet Education Center, formerly Petcoach. Intermittent, painful lameness in dogs of her breed is often related to slipping patella, hip problems (for the hind leg) and sometimes elbow dysplasia (for the front leg lameness). A visit at your local vets is recommended. Full clinical examination should allow making the diagnosis and starting treatment, if required.

This symptom usually happens with a condition called patelar luxation (knee cap injury), this is a condition that requires treatment only if your dog is in pain otherwise it is advised to leave it. the treatment is surgical.

With Axel I would be worried about swelling due to an abscess, fracture, or tumor if the muscle or bone. Hip dislocation can also cause a bump appearance but usually the bump is actually up above there the hip is located as it dislocates cranially most often. If he is not bearing weight then he is in significant pain and in my book this warrants a vet visit ASAP, including an emergency vet if he seems painful/unable to rest or relax at home. An X-ray of the leg will be needed to further evaluate what is going on.