Arthritis is a group of diseases which causes painful inflammation & stiffness of the joints. It means joint inflammation; the term is used to many types of joint diseases & conditions that affect joints, the tissues that surround the joint & other connective tissue.
1. Hazrat Abu Darda رضي الله عنه says that a dish full of Fig (التين) (Anjeer) was presented to Nabi ﷺ once & Nabi ﷺ said us, to eat it & further said, if anyone asks me, that any fruit has been sent from Paradise (الجنة), so I will say, this is the fruit, (teen & yes it is from Paradise (الجنة) & is amongst the dry fruit of Jannah & also said, eat it, & it is a cure for piles (البواسير) & arthritis (النقرس).
[Ibn Abu Bakr Al Jauzi / At-Tibb-e-Nabawi Harfutaa]
2. Hazrat Abu Zar رضي الله عنه also narrates the same above, with difference in some words.
[Kanz al-Ummal: 28280]
3. Ibn Abbas رضي الله عنهما said: "There are 360 joints & each of them owes sadaqa (charity) every single day. Every good word is sadaqa (charity). A man's helping his brother is sadaqa (charity). A drink of water, which he gives, is sadaqa (charity). Removing something harmful (thing) from the road is sadaqa (charity)".
[Al-Adab Al-Mufrad: 422; Book. 24, English Book. 24, Hadees. 422]
4. Narrated by Abu Hurairah رضي الله عنه Nabi ﷺ said: "There is a (compulsory) Sadaqa (charity) to be given for every joint of the human body (as a sign of gratitude to Allah) every day the sun raises. To judge justly between two persons is regarded as Sadaqa & to help a man concerning his riding animal by helping him to ride it or by lifting his luggage on to it, is also regarded as Sadaqa & (saying) a good word is also Sadaqa & every step taken on one's way to offer the compulsory prayer (in the mosque) is also Sadaqa & to remove a harmful thing from the way is also Sadaqa".
[Bukhari: 2989; Book. 56; English vol. 4; Book. 52; Hadees. 232]
Please read lesson no. 5 Anjeer (fig) to learn more about it.