The short answer to your question is yes, spinning is good (when cleared by the physical therapist) and miles on the bike in spring will be good.

The longer answer is follow instructions from your physical therapists, be patient, and quit running, spin - don't mash on the bike and in spin class. Weight loss comes with miles on the bike.

I'm 50 years old. In April of '08 I had ACL replacement, repair of some MCL damage, removal of a large portion if meniscus, and bone resurfacing on both patella and femur of my left knee - the full meal deal. During recovery, spin classes became my main strength building exercise, which lead this summer to my return to more serious cycling after a 25 year break.

I don't know how old you are, but at my age, recovery took a while. I only just now feel as though my surgical knee is nearing 100% of what it was before the injury. By the end of this summer though, thanks to cycling, I'm in better shape than I've been in probably 25 years. I'm 5'10 and my weight went from 215 prior to surgery to 190 now.

The best news is that the arthritis in both knees seems to be reduced by cycling. When I travel for work and am off the bike for a week or more, I notice my knees bothering me. Within a few days of being back on the bike regularly, the pain is reduced significantly.