My hands have been sore after dozens of punches with MMA-style light gloves on a heavy-bag.
I'm wondering if many strikes to a heavy-bag (many of which likely land on the proximal (third from end of fingers) phalange bones rather than being "good" 2-knuckle-punches) over a long period of time could lead to arthritis.
I don't think that there are enough studies on this idea, but I'd use common sense to say, 'yes, it definitely can.' But the better you wrap your hands and wrist with proper hand wraps and gloves, you can make your joints last much longer. It's a risk that you have to take if you want to become tougher through training, but proper handwraps and gloves will definitely help your hands last much longer. You should have never used only mma gloves or just boxing gloves alone. Always use hand wraps underneath.
The general scientific status of arthritis, its causes and why it is causing pain is still "we do not know for sure".
In general, the current overall understanding about arthritis that is causing problems is that it not caused by loading the tissue (impact, traction, torsion) as such.
The main risk factors are loading it too much too soon, ie. peak stress without your body being used to these stress levels at all (not giving it time to adapt to forces, which takes weeks to months with connective tissue, bones, and joints even for little steps), connective tissue disorders, and bad nutrition/systemic disorders.
Thus, as long as you do not have a systemic problem like diabetes or hypermobility, good nutrition, and start slow, building up the impact and generally the amount of stress over years, you are fine.
If your idea is to start punching a bag 3-5 days a week at full force without ever having done it, you are bound to have problems regardless of your overall health status.
Sources: Being in training as a physiotherapist and having listened to countless podcasts with world-leading scientists and specialists in the treatment of arthritis.
MMA style gloves (and boxing gloves) do not provide adequate protection for your hands. You need hand wraps under the gloves. You are damaging your hands - specifically the connective tissue and it will get worse as you continue.
