Using Peripheral Nerve Stimulation (PNS) to Treat Chronic Post-surgical Pain (CPSP) After Knee Surgery

Inclusion Criteria:

   - At least 21 years old

   - Underwent a primary or revision unilateral TKA

   - Completed all CHOIR questionnaires before and after TKA surgery

   - Persistent postsurgical knee pain ≥ 5 of 10 during ambulation as demonstrated on the
   CHOIR assessment.

   - Must meet the definition of chronic pain.

      1. Pain that continues or is expected to continue for longer than 3 months from its
      initial onset or

      2. Persistent pain that at the discretion of the physician has not resolved within
      the normal time course of healing or

      3. Pain requiring opioid use beyond 30 days.

Exclusion Criteria:

   - Patients with a pre-operative history of moderate to high dose use of opioids (≥ 50
   morphine milligram equivalents (MME) average per day)

   - Patients taking opioids for reasons other than pain in knee that underwent TKA

   - Patients with arthrofibrosis or indicated for manipulation under anesthesia

   - BMI >35

   - Uncontrolled Diabetes Mellitus Types I or II, indicated by an HbA1c >7.0% within the
   last 3 months

   - Vulnerable population (e.g. pregnant women, prisoners, minors, or employees)

   - Deep brain stimulation (DBS) system, an implanted active cardiac implant, or any other
   implantable neurostimulator whose stimulus current pathway may overlap the SPRINT
   stimulator's current pathway.

   - Any other condition that may interfere with the ability to participate in a clinical
   trial (e.g., anatomy that may interfere with lead placement, nerve damage in affected
   leg, pain caused by knee implant requiring revision, compromised immune system) as
   determined by the Investigator

   - Workers Compensation