Hi, thanks for writing to HCM. As your xray could not show up an bony lesion, the swelling could be due to soft tissue
pathology and most probably, it could be "dequervains disease". This problem presents as small, tense swelling which produces severe pain
with the movements of the thumb and wrist.
Initially, the condition can be managed conservatively with antiinflammatory medications and ice compressions. If there is no response to this, then a local steroid
injection at the site of maximum tenderness will resolve the problem.
If everything else fails, then a surgical release is needed. Hope this helps