stiff joints?

You didn't mention which tendon she tore. Did the vet take x-rays to confirm the diagnosis? A lot of times vets diagnose knee issues in small dogs when there's an underlying problem dysplasia or arthritis. Even the best vets can do this - Tully's ortho vet missed her extremely arthritic hip when she diagnosed the shoulder injury. She only xrayed the shoulders because laxity in ligaments shows up readily on manipulation, whereas dysplasia and arthritis doesn't. Yes she had a shoulder injury, but it was the result of a bad hip. Was another 6mths of worsening limping before we did an xray of the hips, and a little later we checked the knees just in case.

I would definitely have it checked by a vet, an orthopaedic vet if you can afford it. It does sounds very much like arthritis secondary to dysplasia. Deska was diagnosed with arthritis (degenerative joint disease) in his elbows at 3yrs old and had been showing signs for around 6 mths (took a while for the diagnosis). It's really important to get an early diagnosis so you can start a regime to reduce the degeneration - injections, exercise and dietary.

And yes they can still run like the wind when they are sore, adrenalin is good at masking pain and often the pain only kicks in at night when the muscles relax. Deska continued doing flyball for several years and will still chase bicycles, heck Tully chased some kangaroos yesterday and she's getting a new hip.

 

I just want to chime in to second Caro's info. The best thing I did for my dog when she was limping was take her to (several) recommended ortho vets. It's a bit pricier, but well worth it.

 

The shifting feeling does usually mean knee (cruciate). Arthritis can result from a cruciate tear, and cruciate problems can occur due to dysplasia, worth checking if you can.