Yes, tendonitus! Looong answer for context I developed tendonitus commonly known as 'trigger finger' very shortly after starting Ofatumumab (brand name Kesimpta), and have seen others on U.S. forums saying the same. Obvs some of them have guns so the 'trigger finger' makes sense, like Repetitve Strain Injury for compulsive shooters, lols. I asked Neurologist about it, of course they said it could not be realted to Ofatumumab. My trigger finger Tendonitus comes and goes, one hand only, and has mostly been absent. However it then showed up in the other hand as swollen fingers with tendonitus the same year. Then it appeared in my elbow about a year later, which has been persistent and gradually accelerating in severity. So after a long wait I recently had detailed scans which show inflammation in both hands and one elbow. For context I have been taking Ofatumumab for 2.5 years - one of the first to choose it. Rheumatologist advises that it is not a known side effect of Ofatumumab based on papers from the Ofatumumab trials. Note that Ofatumumab is a newish treatment so when used at scale there may be emerging insights on effects that quantities and duration of trial participants did not show at that time. If you really want to know, get checked out for Rheumatoid disorders, on NHS prepare for a long wait and being psuhed away due negative results in blood tests, be warned although we feel it and can see swelling sometimes, only detailed imaging scans will show it, not XRays or ultrasound. I tested negative for all Rheumatoid indicators twice, a year apart with all the above. Maybe don't go there, because it's another rabbit hole like MS, meaning 'immune' diseases like MS that science has yet to err, fully understand. Note Rheumatoid Disease Modifying Drugs do lessen symptoms for many, and are most effective early in disease course, but don't work at all for some, they all come a price of a compromised immune system and err other 'etc' unknowns. Note MS B cell depleter Rituximab is prescribed for arthritis and many arthritis drugs are low dose Chemo like Ofatumumab and Ocrelizumab.. with medicines like Ofatumumab, which from the little research I have seem to be repurposed continual low doses of decade(s) old cancer therapies. When does it happen most - same as you.. after inactivity of the limb and fingers, sleeping being right up there.. especially sleeping on the limb or compressing fingers for a while. I also notice cold exacerbates it, a little frustrating that no one has a clue Thank you for asking, it's made me feel slightly less batty, as I though it was just me and some U.S gun lovers :)

Hi @Kiko41 , this is something not new but has become more regular in the last month or so. The Index Finger on my left hand locks for a few seconds before giving an uncomfortable feeling, then reverting back to normal.I remember it was my whole left hand that used to lock and seize up befoe Diagnosis or Meds.