Study to Evaluate a Preop Dose of Brivoligide Injection for Pain After Knee Replacement in Patients With High PCS Scores

Inclusion Criteria: * Score of 16 or greater on the PCS scale * Scheduled for primary unilateral TKA with spinal anesthesia as the primary anesthetic for painful osteoarthritis without congenital knee pathology * American Society of Anesthesiologists Physical Status Classification System ≤ 3 * Medically stable for elective surgery with spinal anesthetic as determined by the Investigator * Body mass index of 18-45 kg/m2 * Stable medical regimen at least 1 week before randomization * Able to read and understand study instructions in English or Spanish, and willing to comply with all study procedures Exclusion Criteria: * Target knee \> 20 degrees valgus or varus deformity, evidence of significant bone loss or ligamentous laxity, or existing major hardware that requires removal during TKA * Inflammatory arthridities (e.g., rheumatoid arthritis, lupus, ankylosing spondylitis, psoriatic arthritis), with the exception of clinically stable/non-active gout * Undergoing concomitant surgical procedures or non-elective TKA, or contralateral knee is likely to require TKA within 6 weeks (or would interfere with study assessments) * Use of cryoneurolysis (including Iovera) on the current operative knee region within 6 months prior to randomization and/or at any time through the duration of the study * Planned use of general anesthesia as the primary anesthetic; planned use of neuroaxial (intrathecal or epidural) opioids, or any use of extended release/long acting opioids or ketamine preoperatively and/or at any time through the duration of the study * Use of more than 40 mg per day (on average) of oral morphine or its equivalent within 1 month prior to randomization * Current neurologic disorder, which could confound the assessment of pain (e.g., Parkinson's, Multiple Sclerosis) * Unstable mental condition and/or evidence of an uncooperative attitude in the opinion of the Investigator; subjects diagnosed with schizophrenia, prescribed antipsychotic medications or MAOIs * Women who are pregnant or nursing * Subjects engaged in pending or active litigation, or seeking disability compensation; subjects whose cases have been settled or finally decided are not excluded * Participation in a clinical trial with the last dose or intervention within 1 month of randomization, or planned participation in a clinical trial during this study * Previous participation in any study involving brivoligide injection