In this study, patients scheduled to undergo total knee arthroplasty (TKA) will be screened through a survey for patients with central sensitivity and patients with neuropathic pain as preoperative evaluation.

It is designed to evaluate the effectiveness of pregabalin with the decision to prescribe duloxetine by dividing patient groups according to central sensitization and neuropathic pain.

Screening for central sensitization and neuropathic pain will be performed two weeks in advance of surgery for patients scheduled to undergo total knee arthroplasty, and is performed through a central sensitization questionnaire and neuropathic pain survey. Through the Central Sensitization Inventory, if the score is 40 or higher out of 100 points, it is considered as the subject of central sensitization. And 13 or higher based on 38 points are considered as the subject of neuropathic pain.

Among the patients who meet these two criteria, only those who agree to the study are targeted. The same probability is assigned by a randomized table two weeks before surgery to a group taking duloxetine and pregabalin and a group taking only duloxetine.

In the case of patients with central sensitization and neuropathic pain, both the experimental group and the control group will take medicine for 10 weeks from 2 weeks before surgery to 8 weeks after surgery. The experimental group takes one pill of duloxetine 30 mg, one pill of pregabalin 150mg after breakfast and one pill of pregabalin 150 mg after dinner. The control group takes only one pill of duloxetine 30 mg after breakfast.

A total of 10 weeks' worth of drugs will be provided two weeks before surgery, and medication compliance will be evaluated based on the number of unused drugs returned by the test subject when the drug is returned. In order to evaluate medication compliance, clinical trials should record the number of drugs provided and returned at each visit and the discontinuation date. Subjects must receive medication guidance on the drug-taking schedule. When the clinical trial is completed or terminated in the middle, the unused or partially used drugs must be returned to the clinical examiner and discarded after confirmation.

Relief drugs can also be taken up to six tablets a day, up to two tablets of 650 mg of Tylenol ER Tablets(acetaminophen) once in both groups.

Anthropological information (gender, age, weight, height, body mass index) and outcome variables (VAS scale for checking the degree of pain) are analyzed for the subjects of the study among patients with central sensitization and neuropathic pain.

The subjects will be collected for three months after surgery in both the experimental group and the control group, and the data will be organized and the results will be derived after the last subject's three-month collection.

From immediately after surgery to three months after surgery, we will evaluate the side effects complaining in the subject group. Side effects will be evaluated through interviews with patients during outpatient visits. The above clinical evaluation is observed during the daily treatment process, and the method performed in this clinical trial is judged to have no unpredictable side effects during the current clinical process.

Inclusion Criteria:

• Patients for total knee arthroplasty over the age of 19
• Patients who have the will or ability to follow the doctor's instructions, including rehabilitation treatment such as joint exercise.
• Patients understand this study and agree in writing by the patient's own or by the patient's representative to participate in the study.
• Patients with central sensitization and neuropathic pain.

Exclusion Criteria:

• Rheumatoid arthritis
• Other inflammatory arthritis
• Neuropsychiatric patients
• Hepatic insufficiency
• Renal insufficiency
• Allergy or intolerance to study medications
• Patients with an acetylsalicylic acid of IV (angina, congestive heart failure, dementia, cerebrovascular accident)
• Chronic gabapentin or pregabalin use (regular use for longer than 3 months)
• Chronic opioid use (taking opioids for longer than 3 months)
• Alcohol, drug abuser
• Narcotics addiction