The phrase "arthritis problems" refers to difficulties or issues related to arthritis, which is a condition that causes inflammation, pain, and stiffness in the joints. Full definition
Older cats with arthritis problems may find it difficult to step into the litter box. (vetmed.tufts.edu)
You can read about arthritis problems in dogs and what can be done for them here. (2ndchance.info)
And if you've been hiking with your dog for years, but it is developing mild arthritis problems, there's no reason to quit hiking — just check with your veterinarian to see if a prescription for anti-inflammatory pain medication will help prevent your pooch from being sore afterwards. (ahna.net)