My Husband Just Had Knee Replacement Surgery. Since The Anesthesia

My husband just had knee replacement surgery. Since the anesthesia wore off, he has had headaches (for 43 days that wake him up out of his sleep), arm and wrist pain and numbness in left arm only that gets worse when he sleeps (it wakes him up out of his sleep). What could be wrong? He has seen at least 3 doctors and nothing has helped.