The treatment of choice for a Volar Barton is surgery and fixation with plate or pins, as the fracture
is very unstable. You must have been casted perhaps because the fracture was undisplaced. However, if it has been almost 4 months post fracture, start actively mobilizing your wrist and fingers. You could use a physiotherapy
ball for the same. You need to consult a physiotherapist first and if the pain isn't relieved, go back to your Orthopaedician for Xrays and evaluation.