Hello, As what I understand by history is that, the cramps are the dude to lack of sodium in the muscles of the flexor group. Also, this can occur due to lack of usage of the hand to its efficiency. You mentioned about the plate in the wrist, that means you had a displaced fracture which may have disturbed the normal muscle tissue which has now been giving a lot of cramps. Thumb movement is restricted, means it s a radial bone fracture to be assumed. And the plate is restricting the thumb joint to be flexible. Of course, physiotherapy will be advised to achieve the maximum outcome of the thumb joint, because of mobility to its close to normal physiological movements can lead to muscle cramps. Undergo physiotherapy for regaining the maximum possible thumb mobility so the muscle can achieve the normal physiological functions which can help the sodium channels to work better and avoid cramps. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Jay Indravadan Patel, Physical Therapist or Physiotherapist