I have osteoarthritis through my left hip, which has eroded the joint to the extent that my only real option is to have a hip replacement (September, YES!)
While I used to run endurance-style (racking up 16 - 20km daily) as a teenager, thankfully I stopped that and turned to weight-training in my early 20s. Consistently training with challenging weights, ensuring proper technique and balancing front/back, pushing and pulling, upper and lower body has resulted in NO muscle wastage. According to my surgeon, this is extremely rare in cases of osteoarthritis and he has recommended I stick with my weight-training and low-impact cardio training. My left leg and hip are particularly vulnerable to post-training tightness and soreness that can keep me up in the middle of the night sometimes, but I have an arsenal of tools for when this happens. They are also great for back and neck tension/soreness, calf and plantar fascitis pain.