I-Corps: Translation Potential of a Skin-Covered Bone-Anchored Endoprosthetic Thumb for People with Amputation

This I-Corps project focuses on the development of a skin-covered, bone-anchored, endoprosthetic thumb for people with traumatic amputation. About 6,000 people in the U.S. each year suffer a traumatic thumb amputation, resulting in the loss of about 40% of overall hand function. Existing externally worn prosthetic thumbs do not yet meet patient needs for a device that restores thumb length, form, appearance, and touch sensation. Surgical reconstruction methods such as digit transfer or bone grafting require more surgeries and sacrifices than many patients are willing to make. An endoprosthetic thumb is expected to restore more natural function, comfort, and appearance than external prostheses without the need to harvest healthy donor tissue. Consequently, patients will have better overall functional ability, employment opportunities, independence, confidence, satisfaction, and well-being. This I-Corps project utilizes experiential learning coupled with a first-hand investigation of the industry ecosystem to assess the translation potential of the technology. This solution is based on the development of new methods and technologies to interface living skin with artificial implant materials. The endoprosthesis are anchored to a residual bone in the thumb and covered in the patient’s own living skin using one or more skin flaps or grafts. Hand, plastic, and microvascular surgeons identify existing or new surgical methods to cover the endoprosthesis while restoring a natural appearance and some skin sensation. Development of device materials and geometries support the overlying skin to ensure that it is durable with typical use and resilient to trauma such as cuts, scrapes, and bruises. In addition to the patient user benefits described above, the endoprosthesis benefits surgeon users by providing an off-the-shelf solution to surgically reconstruct thumb length with less burden than digit transfer and bone grafting. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.