| Requirement | Constraint | Verification | Validation |
| 1. The device must allow adjustment of plantarflexion and dorsiflexion to match the patient’s current phase of rehabilitation. | – The device must be easy/intuitive to adjust ROM settings. – The device must minimize the risk of tissue damage, falls, or excessive fatigue. – The device must minimize the risk of reinjury. | TBD | TBD |
| 2. The device must allow adjustment of abduction and adduction to match the patient’s current phase of rehabilitation. | – The device must be easy/intuitive to adjust ROM settings. – The device must minimize the risk of tissue damage, falls, or excessive fatigue. – The device must minimize the risk of reinjury. | TBD | TBD |
| 3. The device must allow adjustment of inversion and eversion to match the patient’s current phase of rehabilitation. | – The device must be easy/intuitive to adjust ROM settings. – The device must minimize the risk of tissue damage, falls, or excessive fatigue. – The device must minimize the risk of reinjury. | TBD | TBD |
| 4. The device must actively assist the ankle range of motion during the active recovery phase. | N/A | TBD | TBD |
| 5. The device must tolerate loads without loss of structural integrity. | – The brace must be durable enough to withstand daily long-term use. | TBD | TBD |
| 6. The device must be lightweight. | – The brace must be designed with inclusivity of a wide range of age groups and mobility levels. – The device must minimize the risk of tissue damage, falls, or excessive fatigue. – The device must minimize the risk of reinjury. | TBD | TBD |
| 7. The device must be comfortable. | – The brace must be designed with inclusivity of a wide range of age groups and mobility levels. | TBD | TBD |
| 8. The device must allow fast switching between the three rehabilitation phase modes. | N/A | – The device’s mode control will be confirmed by testing the success rate and duration of the mode switching. | TBD |
| 9. The device must constrain the range of motion of the ankle to match the patient’s current phase of rehabilitation. | N/A | – The device’s accuracy will be confirmed by comparing range of motion readings to a fixture with set angles. | TBD |
| 10. The device must provide a controllable active element capable of assisting the patient through a prescribed range of motion during the sub-acute phase. | N/A | – The device’s active component control will be confirmed by comparing range of motion readings to a fixture with set angles. | TBD |
| 11. The device must allow clinicians to set a custom range of motion boundary for each plane of motion within the sub-acute phase. | N/A | – The device’s active component control will be confirmed by comparing range of motion readings to a fixture with set angles. | TBD |
| 12. The device must include a fail-safe that prevents motion beyond clinician-set limits. | N/A | – The device’s fail-safe mechanism will be confirmed by attempting to rotate the device beyond the constrained range of motion and measuring further motion beyond that range. | TBD |
| 13. The device must include an emergency shut-off mechanism that rapidly stops all powered motion. | N/A | – The function of the shutoff control will be confirmed by the the measurement of time that it takes for the device to return to a neutral position from the time that the shut off was activated. | TBD |