Individualised 3D printed mechanical partial hand prosthesis and Masquelet technique following bilateral partial hand amputation: A case report

Abstract

Introduction Bilateral partial hand amputations severely reduce function. Losing multiple fingers, especially thumbs, which provide about 40 % of hand function [1] limits grasp and independence. Crush injuries often cannot be fully reconstructed [2]. Partial hand prostheses fill a gap when reconstructive surgery is not possible [3]. Modern 3D scanning and printing allow rapid individualised prostheses. Case Presentation A 62 y music performer’s hands were crushed by a press, causing traumatic amputations of all fingers except the right thumb and index, part of the left thumb. Emergency surgery involved debridement, osteosynthesis of the remaining digits, attempted replantation. Nonviable fingers were amputated. Over the next year the right index developed chronic osteomyelitis with a comminuted fracture. After failed conservative care, sequestrectomy and Masquelet technique with a polymethylmethacrylate (PMMA) spacer reinforced the bone. Prostheses were considered only when no other treatments remained. Once the wounds healed, palms were laser scanned with a HandySCAN 700 to capture residual anatomy. Anonymised 3D scans were transferred into Fuse CAD to create digital models of a mechanical left hand prosthesis with custom sockets, finger segments. Discussion Digital fabrication provided precise, patient specific prosthesis. Reports show that custom 3D printed devices improve grasp and fit [4]. A mechanical design was chosen because body powered prostheses are lighter and more durable than myoelectric prostheses [5]. The HandySCAN 700 captures up to 480000 measurements s⁻¹ using laser triangulation enabling accurate custom prosthetic design [6]. Although many body powered partial hand devices can be coupled to preserved joints, digits this case used a self contained mechanical prosthesis without residual finger actuation. Masquelet technique reinforced the index finger. Its PMMA spacer fills bone cavities and provides structural support [7]. Conclusions Digital 3D scanning and CAD based fabrication produced a custom mechanical partial hand prosthesis that should restore functional grasp and improve the patient’s independence. Precisely matched to the residual palm this printed lightweight body powered device provided a stable, comfortable interface and may offer a feasible option when multiple digits are amputated and not reconstructable.