Does anyone any information on bilateral premature closure of the distal ulnar?

My 9 wk Great Dane is starting to walk on the insides of her front paws. The vet said it could simply be that her ulna is slow growing, or it could be premature closure of the distal ulnar. We're going back in 2 weeks - if it's not improved he'll x-ray to see if the growth plate has closed. Can't find much info on the internet as far as stats - how common is this? What percentage of dogs that present with those symptoms simply have a slow-growing ulna? Kind of freaked out - 9 days prior he gave us a free new-pup visit, but yesterday there was no charge to look at her paws either - makes me think something is really wrong and he knows it! Any thoughts? Any chance that I'm worried for nothing? Thanks!