Avie has LP.. (she is grade 2.. one leg is a little worse and is borderline 3) she does NOT show ANY signs of PAIN, AT ALL thougH! you can feel it pop in and out sometimes though.. 
 
we give her a glucosomine supplement! (we have tried a couple..) and COSEQUIN is what we have been using for a while now.. it is BY FAR the BEST one we have found!! (of course, you can not reverse this.. but you definitely can MAINTAIN it and help stop it from getting worse!) i would NOT recommend surgery, until your baby is ACTUALLY SHOWING signs of PAIN!! 
(ALSO.. we DO have stairs for the couch and the bed! 

)  
here is a link to the supplement we use: (COSEQUIN)  
Cosequin Reqular Strength 
(they also have a 'bonelet', also made by cosequin: 
COSEQUIN Bonelets Hip and Joint Supplement for Dogs - 75 Chewable Tablets)  
AND here are a couple links about LP:  
Medial Luxating Patella - VeterinaryPartner.com - a VIN company!  Medial Patella Luxation in Dogs#  
Peninsula Animal Hospital - Veterinarian In Newport Beach; CA; USA :: Luxating Patella   