Cat doesn't always poop in litterbox - behavorial?

I've had my Oscar for 4 years now and off and on he will go through stages where he will poop on the floor instead of in his litter box.  He always does it in front of it.(the litterbox)  The litterbox is cleaned everyday and sometimes this happens after once it has just been cleaned.  When he was younger he had a bad declaw and had a hard time walking and using his litter, could this be a trauma that still affects him?  I'm worried about him and was wondering if there is anything I can do for him when he is going through this stage. He's naturally a big cat and is 20lbs.

Thank you,
M. and Oscar

[Dr. Carol Osborne, DVM]

Litter box issues are quite common in cats. Checking with your vet first to rule out a health issue is wise. Be sure a kidney problem and/or urinary tract infections is not present. The number of cats in your home, type of litter, depth of litter, cleanliness of the litter box and placement of the box are all issues that affect cats using the litter box.

Big cats like yours especially because of the previous toe injury may have pain and/or arthritis issues which also causes them to be reluctant to climb into their liter box. Being sure the sides of the litter box are low helps to resolve this issue.

I am glad to discuss this further please feel free to contact my office.

Best Wishes,
Dr Carol Osborne, DVM