9 month Old lab with swollen hind leg for 4 months
 

My name is Alicia and i am currently residing in Pakistan... I have a 9 month old chocolate labrador (Brutus Maximus) who i love very dearly....However due to overexertion his right hind leg has been swollen for the last four months he has had every test done under the sun.. his blood test and xray came out perfectly normal no broken bones and no raised lymph count. His leg has been swollen for the past 4 months though and i am at a loss as to how to help him...he has been through a 2 courses of antibiotics.. diuretics..and antiinflammatories..what is left!!?? a cast? i just dont know what to do! Sometimes he is runnning and jumping like normal as if nothing was ever wrong and then every few days he stops walking on his leg all together!!! He eats and passes stool perfectly fine and normaly and he is always very happy
someone plz help me!!!!!!!!

Is the leg swollen at a joint or along a bone somewhere? And have you tried resting the leg (curtailing his exercise...yeah, I know... 9-month-old choco-lab: irrepressible. :o) What kind of antibiotics was he on?