Dear Rabbi as we recently spoke regarding hand and arm transplants from donors that amazingly are possible albeit still rare and complicated in our days. Could such a transplanted arm be used for putting Tefilin on it? At what point of the process would that be already possible?

Indeed as you explained to me that as a physician and surgeon you are familiar with organ transplants. Yet hand and arm transplants from donors is still in our days uncommon and complicated. As also explained in a Johns Hopkins article, hand and arm transplantation is a procedure to surgically attach a donor’s hand or arm to a recipient, and can be life changing for those who have suffered an amputation or experienced extreme loss of hand function due to illness or injury. It is a complex procedure that involves a rigorous screening process, detailed surgical preparation, up to 12 hours or more of surgery, nerve regeneration, physical therapy and immunosuppressive medications taken for the rest of the patient’s life. As with organ transplants, the area of greatest concern is preventing rejection. There are two kinds of rejection: acute and chronic. Once controlled the chances of success are positive. Horav Shlomo Miller’s Shlit’a opinion is that although there is no certainty of a continuous positive result, once the chances are mostly for the best, one can don Tefilin on the arm with a brocho.