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.