I have tendonitis in my middle knuckle/MCP from a previous injury that seems to have healed but is being very slow to reduce in tenderness/inflammation. My PCP currently has me on a short (1 week) oral steroid cycle (methylprednisolone 4mg) alongside topical anti-inflammatory gel (diclofenac) to reduce the swelling and reevaluate later but, if inflammation returns post-cycle, a cortisone injection into that tendon is apparently the next option. I've heard of the somewhat significant fluid retention/bloating/water weight gain that people go through as a side effect during oral corticosteroid cycles but I've heard no consensus on whether the same side effect is present for localized injections and, if so, for how long (seeing as this injection is supposed to last several weeks/months).
If I end up needing to go with a cortisone injection into my knuckle in order to reap longer term relief of the chronic inflammation, am I signing up for significantly increased fluid retention (and subsequently water weight) for the next few months/duration of relief? I'd like to know as I monitor my weight for any unusual changes for other reasons. Thank you!