Arthrodesis of the interphalangeal (IP) joint of the thumb is widely acknowledged as the indicated treatment for trauma and osteoarthritis of this joint. Joint replacement was offered to a young patient as an alternative treatment after traumatic joint loss of the IP joint in her thumb. This allowed her to maintain motion of the joint as she did not wish to move forward with fusion. In the present case, a Humanitarian Use Device (HUD) was utilized in an off-label manner and placed into the interphalangeal joint of the patient's thumb. The patient did well postoperatively with reasonable pain-free range of motion of the interphalangeal joint with an arc of 40 degrees. We propose that joint replacement is a viable alternative to arthrodesis in select patients who do not wish to be fused. We believe this represents the first thumb IP joint replacement using a semiconstrained joint presented in the medical literature.