Your dog might have hip dysplasia or a spinal subluxation. To help with the limping and stiffness I would give PROMAXOL. It helps to decrease pain, inflammation, and stiffness and stimulate healing. Initially I would give a half dose with breakfast and again at supper. After improvement is seen you can decrease to a whole dose once daily. For longer term management you can switch to ARTHRO-IONX. In addition I find it helpful to follow a holistic approach by giving nutritional supplements to accompany the homeopathic. I would also use PROBIOTICS and OMEGA 3,6,9 to reduce inflammation and strengthen the body. What type of food and water are you giving?
I would also suggest an evaluation by a veterinary chiropractor. If a correction is needed, that can help with better movement and more strength in the rear end. Acupuncture is also helpful. Looking forward to your reply.