There are approximately 2.1 million amputees in the United States, and another 200,000 or so people lose a limb every year. Given those numbers, you’d think it would be relatively easy to populate clinical trials for prosthetic devices, socket designs, surgical techniques, and other technologies related to limb loss. But in truth, it can take many months to round up test subjects who meet the needs of a given project. Many investigations focus on one or more specific subsets of the limb-loss population; others require a representative sample. Moreover, time and travel considerations often exclude potential participants. Even a study that requires as few as a dozen subjects can be a bear to fill out.

Those who do volunteer provide a tremendous gift to the amputee community. And the perks can be pretty good, too. You get to meet incredibly smart, interesting people; you have a voice in shaping the technologies of the future; you might get free medical treatment in some cases; and, if you get lucky enough to participate in an impactful study, you can earn some cache for being present at the creation of the latest, greatest thing.

The WCG Centerwatch database lists dozens of clinical trials that are actively recruiting amputee test subjects. To see the whole list, visit and search on “amputation,” “amputee,” or a related term. We culled a handful of studies that are particularly exciting to us. To get more information about each project (including contact information), click on the title.

Study title: AMI Construction in Lower-Extremity Residual Limbs
Sponsoring institutions: MIT / Brigham and Women’s Hospital
Location: Boston
Purpose: A followup to Hugh Herr’s groundbreaking agonist-antagonist myoneural interface procedure, this trial will focus on modification of prior amputations that were done via conventional surgery. Goals include the adoption of next-gen bionic legs, reduction of phantom limb pain, and restored proprioception and muscle mass.
End date: September 30, 2022
Participants needed: 16

Study title: Personalized Mobility Interventions Using Smart Sensor Resources
Sponsoring institutions: Shirley Ryan Ability Lab
Locations: Chicago, Minneapolis, and Bethesda MD
Purpose: The overall goal of this research is to create a clinical toolkit to predict prosthesis use and function in the community. Combining data from wearable sensors with patient-reported information, the study aims to give clinicians a more responsive set of standards for prescribing prosthesis use, optimizing fit, and improving clients’ quality of life.
End date: September 30, 2023
Participants needed: 125

Study title: Sciatic Nerve Block for Phantom Limb Pain
Sponsoring institution: Northwestern University
Location: Chicago
Purpose: The study will test whether a sciatic nerve block with 2 percent lidocaine can provide immediate, clinically meaningful relief in amputees with chronic phantom limb pain.
End date: March 11, 2024
Participants needed: 20

Study title: Sensory Feedback for Leg Amputees
Sponsoring institution: Louis Stokes VA Medical Center
Location: Cleveland
Purpose: This study will evaluate the effectiveness of simulating sensation in the missing limb by applying small electrical current directly to the remaining sensory nerves via implanted electrodes. These small electrical currents are meant to generate neurological signals that mirror sensory communication that existed prior to amputation.
End date: September 1, 2024
Participants needed: 10

Study title: Patient Reported Outcomes Following Targeted Muscle Reinnervation
Sponsoring institution: University of Wisconsin
Location: Madison WI
Purpose: There is increasing evidence that TMR can promote early use of prosthetics and reduce pain from neuroma and phantom limb syndrome. This study will characterize the functional ability and quality of life of patients after undergoing TMR either at the time of amputation (primary) or subsequent to amputation (secondary).
End date: January 14, 2023
Participants needed: 60