Try not to worry to hard. LP and LS are not a death sentence.
Get some Cosiquin and start to give this daily (as per in the instructions). This is good for now and the long run. IMO - Grade 3 and 4 should have surgery to stop the luxation. If he isn't using his legs or limping or carrying them, this is pain and discomfort, so I wouldn't let it go for too long. At 4 lbs, he will be ok. My Roxy was 4 lbs 9 oz. and had both rear legs done at the same time. My advice is to go to a Board Cert. Ortho Specialist.
Let us know what the BAT results are
and we can help guide you from there
