OCD means osteo - chondritis - dissecans. Simply put this means the cartiledge in your dogs joints is decaying. It can be caused by trauma or even genetics. Chiropractic can help the joints that are compensating for this disease and prevent their wear and tear. Your Vet will usually prescribe meds for pain and inflam. It is also helpful to get your dog on a joint supplement. Liguid Joint Supplement found in Human Health Food stores works great and is cheaper. Just figure out your dogs weight and dose accordingly, since the supplement in the human store is for a 150lb person.
Ask your vet about Adequan injections into the muscle. There has been many cases where this has eliminated the limping and along with Chiropractic and Acupuncture many dogs have lived healthy long lives.