4 weeks old is rather old to catch a swimmer - you'll have a harder time rehabbing this guy, but you have to start NOW. What are you using on the floor? You need something with a lot of grip so the puppy doesn't slip. How bad is it? Can he get up at all? You might need to hobble him for a bit each day and you'll definitely need to work with him - don't let him sleep on his stomach. Some people have talked about setting up a slot that he can walk through so he doesn't fall down, and working him through that.
I have a 'farm house' sink in my kitchen .. filled it 3/4 full of luke warm water and swam my guy 3 X a day for 4 days .. he was right as rain after that. Supported his body with one hand and 'dog paddled' all 4 legs for a few minutes with the other .. Worked very well for me .. Full recovery and you would never know ..
Just sent home a former swimmer 2 weeks ago. I hobbled with masking tape. I put tape right over the hocks: separate tape on each hock, then held pup in desired position and put a connector tape in the middle to keep legs at desired width. I redid middle tape daily if messy. He was right up and running immediately.
During nap times, and at night I turned him on his side once he was asleep as his chest was slightly flat. He soon chose to sleep on his side.
I kept hobbled for 4 days and he was perfect after that as long as he was on a skid resistant flooring. By 6 weeks, he could even run on my slippery linoleum and not have an issue. I also caught mine late, but when I sent him home, his new family (instructor for medical students) couldn't believe he had been a swimmer pup, he was/is perfect.
I would use a sling for a broken arm. stick the puppy in the sling on his back. It will push his legs upwards. Carry him in the sling every chance you get. When you do dishes, watch tv, every chance you get. If you put him in the sling over your shoulder/chest like you would a broken arm, it allows you to do all your necessary chores as well as help rehab him.
Good Luck!
Maybe I jumped the gun by calling my pup a swimmer. She's fine on her front legs, its her back legs. She dosen't have the mobility like her litter mates. She is lagging. On slick surface she slides, on carpet she is better. I'm hoping its just a developmental thing. She is slower then her litter mates. I've never had a pup dragging around her hind legs on a slick surface.
I had a swimmer 2 years ago, and hobbled her at 4 weeks. Within 3 days she was up on her feet and the hobbles were removed. Of course I did change the hobbles daily for the time she was wearing them.
At four weeks a lot can be accomplished by providing a rubber surface to aid in the pup getting up. It will help to roll him in the palms of your hands for about three minutes, several times a day. You'll notice as you do this that there will be a great deal of weight as you turn him to each side. That in itself will help to curve his ribs into their normal position. Hobbling helps a great deal if you're late in noticing the problem. I also put lots of bumps under the top mat and when he falls asleep, rest his side against one of the "hills".
