Total Knee Replacement (TDP) is considered the best treatment option available when conservative methods such as anti-inflammatory or physical therapy fail. However, TDP surgeries are also a serious trauma that causes severe pain in patients. Uncontrollable pain exacerbates the stress response and causes morbidity and mortality by causing negative changes in the neuroendocrine, respiratory, cardiovascular, gastrointestinal, renal and immune systems. Therefore, the relief of pain has very important effects on the patient's recovery process, functional status and quality of life. Transcutaneous Electrical Nerve Stimulation (TENS) is one of the non-pharmacological methods for pain relief in TDP surgeries. This study was planned as a randomized controlled trial to examine the effects of TENS after TDP on acute pain, functionality and quality of life.

Nowadays, it is seen that the results of an increasing number of TDP surgeries increase patient satisfaction and have satisfactory results. However, TDP surgery is a serious trauma that causes pain in patients.

TENS is an easy-to-apply, inexpensive, noninvasive, noninvasive method that uses electrical current to activate nerves with therapeutic effects in the treatment of acute and chronic pain. It is also seen as a promising practice in patients undergoing total knee replacement surgery by the American Society of Regional Anesthesia and Pain Medicine (ASRA) and the European Society of Regional Anaesthesia and Pain Therapy (ESRA).

The study was planned as a randomized controlled study to examine the effect of TENS on acute pain, functionality and quality of life after TDP. The hypotheses of the study; H1a- TENS applied after TDP positively affects the level of pain in patients. H1b- TENS applied after TDP affects the improvement in functional status in patients.

H1c- TENS applied after TDP reduces the analgesia consumption of patients. H1d- TENS applied after TDP positively affects the quality of life of patients. Type of Study: Randomized controlled trial. Method: 52 patients (26 controls, 26 interventions) who underwent total knee replacement surgery will be randomized and divided into two groups as intervention and control groups. TENS will be applied to the intervention group in addition to the routine treatment and care in the clinic, on the other hand, no intervention will be made to the control group other than routine treatment and care. Data will be collected with Patient identification form, Pain Evaluation Form, Visual Analogue Scale (VAS), Analgesic Drug Tracking Form, Joint Range of Motion (ROM) Follow-up Form, Western Ontario and McMaster Universities Arthritis Index (WOMAC), Quality of Life Scale (SF-36).

While evaluating the data, it is planned to be analyzed as randomized.It is planned to use multiple completion methods when there are missing data.Statistical analyzes are planned to be evaluated with the SPSS-24 package program. It is planned to use frequency charts and descriptive statistics in order to interpret the data, parametric techniques for normal distributions and non-parametric techniques for non-normal distributions.

Inclusion Criteria:

• Not have had knee replacement surgery before,
• Having unilateral prosthesis surgery,
• Not having a pacemaker or arrhythmia,
• Not having neurological deficit,
• Absence of sensory loss, paresthesia or hyporeflexia,
• Not having local or systemic infection,
• Not using opioids or TENS before surgery,
• Not having history of chronic pain,
• Not having history of alcohol or drug use,
• Not having a psychiatric history,
• Not having been done to apply epidural analgesia in the postoperative period,
• Not having serious complications after surgery,
• Not having a history of neurological disease (SVO, epilepsy, dementia, etc.),
• Not having active tumor or cancer,
• Not having fractures or dislocations,
• Absence of signs of venous thromboembolism,
• Having an ASA score of I and II,
• Agree to participate in the research and
• Know how to read and write

Exclusion Criteria:

• Undergoing previous knee replacement surgery,
• Having double-sided prosthesis surgery,
• Having a pacemaker and arrhythmia,
• Having a neurological deficit,
• Having loss of sensation, paresthesia or hyporeflexia,
• Having local or systemic infection,
• Having been used opioids and or TENS before surgery,
• Having a history of chronic pain,
• Having a history of alcohol or drug use,
• Having a psychiatric history,
• Administering epidural analgesia in the postoperative period,
• Developing serious complications after surgery,
• Having a history of neurological disease (SVO, epilepsy, dementia, etc.),
• Having an active tumor or cancer,
• Having fracture or dislocation,
• Having symptoms of venous thrombosis,
• Not having ASA score I or II,
• Not agreeing to participate in the study,
• Illiteracy

Due to the nature of the study, patients will not be left blind. The assignment to the groups will be carried out by an independent researcher, and the group will be notified via telephone after the practitioner researcher has approved, evaluated the criteria and performed the pre-tests. At the same time, groups will be named A and B and researchers will be blinded during statistical analysis and reporting.The questionnaires to be applied to the patients included in the study will be administered by an independent researcher.