The Problem
Since the American Civil War, amputation techniques have stayed relatively unchanged, often leading to muscle loss, chronic pain, blistering, infections, and arthritis in patients. In more evolved surgical procedures, it has been discovered that residual bodily material can be repurposed for reconstruction. Despite this advancement, this process had not been applied in amputation medicine.
Throughout the body, agonist and antagonist muscles work in pairs, playing opposite roles to facilitate movement. As agonist muscles contract to produce motion, antagonist muscles relax and stretch to allow the movement to happen smoothly. In traditional amputation, these muscles are disconnected from one another and the remaining bone, reducing neural signaling to only about three percent of its original efficiency. This significant decline in neural communication affects the residual limb, leading to limited control and mobility of the patient’s prosthetic device.
The Approach
Matthew Carty, MD, a plastic surgeon at Brigham and Women’s Hospital (BWH), received the inaugural Stepping Strong Innovator Award in 2014 for developing a groundbreaking procedure that allows patients to control a prosthetic device with the same fluidity as a natural limb. Named the Ewing Amputation after its first recipient, Dr. Carty’s technique connects the lower limb’s agonist and antagonist muscles in a continuous loop, preserving neural signaling and maintaining communication with the brain. This method, known as the agonist-antagonist myoneural interface (AMI) procedure, allows recipients to control their artificial limb with their brain, just as they would a natural limb. When combined with next-generation prosthetics, this procedure offers unprecedented functionality for amputation patients.
What’s Next?
Following the success of the Ewing/AMI procedure on the lower extremities, Dr. Carty adapted the technique for the upper extremities, transforming care for patients worldwide. As of January 2026, the procedure has been performed on 148 limbs across multiple institutions globally.
This innovative approach extends beyond treating traumatic injuries, offering a life-changing solution for anyone at risk of limb loss. One such patient is Morgan Stickney, who had both of her lower legs amputated after battling life-threatening infections and a severe lack of blood flow to her bones. An accomplished swimmer, Morgan has since competed for Team USA in the Paralympic Games, winning four gold medals throughout her career.
The Ewing Amputation has become the standard of care at BWH, of which all lower extremity amputations now utilize this technique that was made possible by The Gillian Reny Stepping Strong Center for Trauma Innovation.
