I hurt the base of my right thumb about a year ago. The immediate area swelled up, so I saw a doctor soon after who diagnosed it as gamekeeper's thumb. I wore a splint for a two weeks and everything was great after taking it off.
However, I recently aggravated it again. It isn't painful most of the time, but sometimes clicks when flexing the entire range of motion (the same way as it did originally after the injury).
What's the best thing I can do now to re-heal (hopefully better) the injury?
"Gamekeeper's thumb" - named because of the chronic injury incurred when rabbit keepers broke rabbits' necks between the base of the thumb and index finger - has more recently been referred to as "skier's thumb", now the most common acute mechanism of the injury. If you fell on an outstretched hand hyperextending your thumb (did it feel as if the thumb was stressed beyond its normal range of motion?) and your doctor was correct, you injured the ulnar collateral ligament (UCL) of the metacarpophalangeal joint (MCPJ) of the thumb. This would cause significant pain and swelling at the base of the thumb in the "web space" between thumb and index finger.
As you can see in the picture on the right, the UCL appears partially torn. If it does not heal completely, it can result in an insufficiency of that ligament. In this case, the condition not uncommonly becomes chronic because of repeated injury to the already weakened UCL. It causes varying degrees of instability of that joint with pain and weakness of the pincer grasp (imagine squeezing an m&m between your thumb and your index finger.)
Initial treatment to optimize ligament healing is immobilization.
What can you do now? If you think you re-injured it, you can apply a cold pack (e.g. a bag of frozen peas wrapped in a dry washcloth) to the thumb as tolerated for ~20 minutes, up to four times per day.
Immobilizing the thumb with a bulky, loose ACE wrap or a commercially available thumb brace in the neutral position will help lessen the pain. You can take acetaminophen or ibuprofen for pain relief if you have no contraindications*.
The best thing you can do is see a doctor (perhaps an orthopedist or a hand specialist would be wise), since chronic pain and instability of the thumb is not insignificant. They can do a thorough evaluation of your thumb and either splint/cast your thumb, give you rehabilitative exercises to help you strengthen your thumb, or recommend surgery if necessary.
*Contraindication = any reason you shouldn't take it.
Always keep a cloth between your skin and the ice pack, and press firmly against all the curves of the affected area. Remove the ice pack if it causes pain, and don't fall asleep with the pack in place.
Gamekeeper's Thumb
Gamekeeper's Thumb: Wheeless' Textbook of Orthopaedics
There is some discrepancies in your question. "I hurt the base..." and then you talk about tendonitis. For me as a medical professional hurting means something like you tripped and your thumb overextended agains ground or you got your thumb crushed in someting. Acute or chronic tendinitis or tendinopathy is usullay assocciated to something repetitive and long lasting movements.
Therefore if you really hurted your thenar area I would make sure there is not any ligament tears present in your thumb. For example a rupture of ulnar collateral ligamenti of thumb, ie. gamekeeper's thumb or skiier's thumb is quite common injury which, if unsuccesfully treated initially, requires surgical repair later to "re-heal". Base of thumb is quite vague term, if your pain and clicking is near first metacarpophalangeal joint, I would be conserned about this injury. If your symptoms are present more proximally injury of carpar ligaments may be present still and those should be ruled out. Clicking is a symptom which usually originates from anatomical reasons, for example a torn supportive ligaments which predisposes to tendon subluxations.
However if you meant that hurting is something repetitive and long standing you may indeed have chronic tenditis in some tendon responsible for thumb extension or adduction. Chronic tenditinis can be really disturbing condition. Curative treatment is hard to obtain and really the only help is immobilisation, avoidance of aggrevating movements and repeated courses of NSAIDs. Bascially I would recommend ANYTHING which even one person have found helpful for chronic wrist or thumb tendinitis.
Chronic tendinitis is also really unsatisfactory for medical professionals since there is so little one can do for the patient, especially if he/she can´t change the working enviroment. In some cases if the condition really persists for a long some kind of tendon surgery may be helpful but results are very controversial.
