Many of you on here gave me positive stories of good outcomes for cruciate surgery,so thankyou again.
While I was still deliberating ddog had good and bad days, but did in fact then rupture a cruciate so we couldn't wait any longer.
He had a TTA and was weightbearing by the next day! He has been really good for a week, staying in his playpen with just quick trips to the garden. Now he obviously feels great and thinks it would be good to go for a run 
It's going to be a long five weeks!