Dog with a persistent front leg limp the vet has had trouble diagnosing

* Species: Dog
* Age: 6

* Sex/Neuter status: Female/Spayed

* Breed: Husky/Shepherd

* Body weight: 50lbs

* History: No previous injuries or relevant issues. She's very active, we used to run or bike nearly every day but have had to slow down a lot because of this.

* Clinical signs: Limping on the front legs, mostly after having just stood up. She started to limp around late December on a front leg when standing up after having been laying down. After a minute of walking the limping usually goes away. Outside walking she shows no symptoms. When playing with other dogs I've heard her cry as if she hurt something and I suspect it is this injury but not sure.

* Duration: On and off, varying in severity for 4-5 months

* Your general location: Eastern Canada

* Links to any test results, X-rays, vet reports etc. that you have: The vet has been unable to identify the problem after two visits. She's palpated both front legs, stretch and manipulated all the joints (paws, wrist, elbow, shoulder) looking for a reaction to try to find where to X-Ray but we've been unable to find anything.

Hi, I'm mostly looking for advice on what we should do next! We've been to the vet twice and they are saying the next step would be a referral to a hospital that can do some sort of special scan.

There was a positive test for Lyme and Anaplasmosis and she has been on Doxycycline for about 2 weeks with no improvement. We're currently resting her for 2 weeks and giving an anti-inflamatory that was prescribed after our most recent vet visit. The vet also had a possible theory that her harness we use was rubbing her shoulder in a way that could cause the issue, we're not using that harness anymore, but I'm a bit sceptical that could be it.
I have a couple short video clips taken recently and a photo of her holding up her paw one day when it was particularly bad and she seemed not to want to put weight on it. The limp in the videos appears to me to be in the right leg, but she was holding up the left paw. The videos and photo were taken the same day https://imgur.com/a/TUyeWXI