Evaluating the Efficacy and Safety of Pregabalin in Total Knee Arthroplasty Patients With Central Sensitization

The study purpose is to determine if giving pregabalin before and after total knee arthroplasty (TKA) can improve pain and meaningful function after surgery in patients that have central sensitization (CS). Central sensitization occurs when the brain (central nervous system) becomes hypersensitized and hypervigilant, over-reacting to any painful (and sometimes nonpainful) stimuli. Patients with greater central sensitization have been shown to have significantly more pain after surgery, including TKA. We are proposing to explore whether treatment with a nerve pain medication, pregabalin, can improve post-operative pain and function in these patients. This medication has been shown to improve central sensitization pain in the chronic pain setting but has not been studied for this purpose in the acute surgical pain setting.

Participants will be identified at the visit in which they are indicated for TKA. Patients indicated for a TKA will be approached about participating in the study. Either at that visit or later by phone or e-mail, interested patients will complete a standard Knee Injury and Osteoarthritis Outcomes Score (KOOS), which is part of the standard orthopedic evaluation. They will also be asked their pain score (on a scale of 0 to 10), and complete the Central Sensitization Inventory (CSI). If they meet study inclusion criteria, and they agree to participate, they will complete the informed consent (in person or on-line) and then be randomized 1:1 to usual care (control group) or pregabalin (study group). The study group participants will take pregabalin starting 7 days prior to surgery. The participant will receive usual medication counseling for this medication. They will also be scheduled to have a pre-operative physical therapy (PT) appointment at the time of their pre-op visit, which will include tests and measures standard to PT, but must include a Timed Up and Go Test (TUG), a Sit to Stand 5 Times Repeat Test (5TSTS) and Patient Specific Functional Scale (SFS) measures.

On the day of surgery participants will be asked about any adverse effects of study medication, and determine need to withdraw from study (for any reason). The post-operative plan will also be reviewed, including dose of study medication, for the pregabalin group. For the pregabalin group the doses will be doubled for 7 days, then reduced for 7 days, then off. All participants will be given standard peri-operative pain management for TKA (a nerve block and/or spinal unless contraindicated, anti-inflammatory drugs (NSAID) and acetaminophen (unless contraindicated) as well as oral opioid (usually oxycodone or hydromorphone) to use as needed for severe pain. All participants will complete standard of practice physical therapy on day of surgery or until discharged to home.

After surgery (usually within 7 days) a physical therapist will perform standard post-operative evaluation and treatment for all participants. This includes a re-evaluation of the same pre-operative functional tests of TUG, 5TSTS and PSFS outcome measures. At this time, the pharmacist will also call the patient to determine if there are any medication-related adverse effects and how much opioid medication the patient is taking at that time (morphine milligram equivalents- MME/day on average).

Standard follow-up after TKA is 6 weeks. At this visit all participants will again complete the KOOS survey, report a pain score, complete the CSI survey and determine, based on patient report, of quantity of opioid medication used (MME). A physical therapist will complete the functional assessment of the TUG, 5TSTS and PSFS outcome measures.