Evaluation of the Phantom X Implantable EMG Sensor System for Myoelectric Prosthesis Control

Inclusion Criteria: 1. Patient has a unilateral upper-limb difference (congenital or acquired) at the transradial or wrist level. 2. The patient currently uses a myoelectric prosthesis or is deemed a suitable candidate for fitting with a myoelectric prosthesis. 3. Patient is a suitable candidate for the implantation of the Phantom X sensor array as assessed by the implanting physician. 4. Patient is at least 18 years old and can provide written informed consent. 5. Patient is willing to comply with study protocol and make required study visits. 6. Patient received amputation ≥ 12 months prior to consent. Exclusion Criteria: 1. Patient has a significant cognitive deficit resulting in inability to follow study directions. 2. Patient has a neuro-muscular deficit and is unable to initiate substantial muscle contraction in the residual limb as determined by the implanting physician or investigator. 3. Patient has another medical condition, which, in the opinion of the Investigator, may cause him/her to be non-compliant with the protocol, confound the data interpretation, or is associated with a life expectancy insufficient to allow for the completion of study procedures and follow-up. 4. The patient has a planned medical procedure (e.g., surgery) during the study period that could interfere with compliance with study visits or assessments. 5. Patient has an allergy to anesthesia or other medication used for sedation in the study. 6. Patient has an active implantable device (e.g. cardiac pacemaker, neuromodulation device) that can potentially interfere with the performance of Phantom X system. 7. Patient may require an MRI during the study duration. 8. Implantation of the device poses a health risk to the patient as determined by the implanting physician. 9. Women who are breastfeeding, currently pregnant or planning to become pregnant during the duration of the study or have a positive urine pregnancy test at screening.