So sorry to hear poor Thomas has a poor leg, paw. Have you tried RICE - Rest, Ice, Compression and Elevation. I expect the last one will be hard, but 3 out of 4 ain't bad.
Also if he is slightly overweight, perhaps put him on a little diet to get him back to the comfort range of weight.
Wishing you luck with everything - poor ol' Thomas. Get better soon. Sending love and hugs

Lizzie xxx