The goal of this clinical trial is to analzye return to pre-injury activity level on study participants with lateral ankle instability undergoing a modified Bröstrom reconstruction procedure for repair of the ATFL. Study participants undergoing ATFL reconstructive procedure using the ARTELON FLEXBAND System as an augmentation device will be compared to study participants undergoing a standard modified Bröstrom procedure alone. Clinician reported safety and functional outcomes measures will be collected at baseline; and at 2-, 6-, 12-, 18 and 26-weeks and 1- and 2-years post-surgery.

Inclusion Criteria:

1. Subjects between and including the age of 18-75 at the time of surgery.
2. Subjects who were diagnosed with lateral ankle instability by physician clinical assessment.
3. Subjects who will undergo a modified Bröstrom procedure for an ATFL repair with or without FLEXBAND augmentation device (does not require an isolated repair).
4. Subjects that are able to understand, complete and sign the Consent Form.

Exclusion Criteria:

1. Significant secondary procedures done at the time of repair, including significant osteochondral lesions and/or significant microfracture of the talus or tibia that warrant modifying the typical lateral ligament repair post-op rehab protocol (minor microfractures and OCD lesions that do not warrant major bone debridement, synovectomies, and bone spur/osteophyte removals are allowed).
2. Any concomitant orthopedic procedure that will extend the post-op rehabilitation (e.g., casting/immobilization) beyond the routinely prescribed rehab protocol following an ATFL reconstructive procedure.
3. Subjects undergoing a Calcaneal osteotomy.
4. Subjects requiring major additional tendon surgery (i.e., peroneal tendon repair or tenodesis).
5. Neuropathy.
6. Subjects with diabetes, who, in the opinion of the investigator, are not sufficiently controlled.
7. BMI greater than 40 kg/m2.
8. Subjects with active Worker's Compensation Cases
9. Any subject with a history of infection of the ankle predating the ankle repair.
10. Subjects with a systemic ligament laxity disorder (i.e., Ehlers-Danlos Syndrome).
11. Any orthopedic issue outside of the ankle that the Investigator feels may impede functional endpoint outcome measures.
12. Subjects who have a medical history that would likely make the subject an unreliable research participant.
13. Subjects that are nursing or pregnant at the time of surgery.
14. Subjects with physician assessed untreated alcohol or substance abuse at the time of screening.
15. Subjects who are currently enrolled or participated in another investigational device, drug, or biological trial within 60 days of screening.

Unknown at this time.