The goal of this clinical trial is to learn if transcutaneous electrical nerve stimulation (TENS) can reduce perioperative pain in older adults with hip fractures. It will also evaluate its effects on physiological and psychological outcomes. The main questions it aims to answer are:

Does adding TENS to usual care during the preoperative phase reduce pain intensity and analgesic consumption? Does TENS affect pressure pain threshold and vital signs (blood pressure, heart rate, and respiratory rate)?

Researchers will compare active TENS to sham TENS (no perceptible stimulation) to see if TENS is effective in reducing pain and improving related outcomes.

Participants will:

• Undergo a standardized baseline assessment, including evaluation of pain, vital signs, anxiety, discomfort, and pressure pain threshold
• Complete questionnaires assessing quality of life, physical activity, depressive symptoms, anxiety, fear of falling, and pain catastrophizing
• Be randomly assigned to receive either active TENS or sham TENS
• Receive a single 45-minute TENS session
• Have their analgesic use recorded for the 24 hours before and after the intervention.

Hip fractures in older adults are commonly associated with significant perioperative pain, which is often managed with opioid analgesics despite their potential adverse effects. Non-pharmacological and non-invasive strategies, such as transcutaneous electrical nerve stimulation (TENS), have been proposed as adjunctive approaches for pain management. While previous studies have primarily focused on postoperative applications, the effects of TENS during the preoperative phase remain unclear.

This randomized clinical trial will include 32 older adults diagnosed with hip fracture. After providing written informed consent, participants will undergo a standardized baseline assessment. Demographic and clinical data, including age, sex, marital status, and education level, will be collected through an anamnesis form.

Physiological and clinical outcomes will be assessed before and after the intervention. These include vital signs (blood pressure, heart rate, and respiratory rate), pain intensity, discomfort level, anxiety level, and pressure pain threshold. Additionally, validated instruments will be applied once prior to the intervention to assess broader health domains, including quality of life (SF-36), physical activity level (International Physical Activity Questionnaire - IPAQ), depressive symptoms (Geriatric Depression Scale), anxiety symptoms (State-Trait Anxiety Inventory), fear of falling (Falls Efficacy Scale International), and pain catastrophizing (Pain Catastrophizing Scale).

Following baseline assessments, participants will be randomly assigned to one of two groups. The intervention group (G1) will receive active TENS, with intensity adjusted to the maximum level tolerated by the participant. The control group (G2) will receive sham TENS, with intensity set at a sub-sensory level without perceptible stimulation. The intervention will consist of a single session lasting 45 minutes.

Analgesic consumption will be evaluated based on the type and quantity of medications used by participants in the 24 hours before and 24 hours after the intervention. These data will be obtained from medical records and prescription information.

This study aims to provide evidence regarding the effectiveness of preoperative TENS as an adjunct to usual care for pain management and its potential influence on physiological and psychological outcomes in older adults with hip fractures.

Inclusion Criteria:

• Older adults (male and female) diagnosed with hip fracture
• Age ≥ 60 years
• Admitted to the hospital inpatient unit (HPS)
• Mini-Mental State Examination (MMSE) score ≥ 20

Exclusion Criteria:

• Conditions contraindicating electrical stimulation, such as presence of a pacemaker, significant sensory loss in the lower limbs, or skin lesions at the electrode placement site
• History of neurological or cognitive impairment that may interfere with understanding of the assessments
• Previous treatment with neuromuscular electrical stimulation (NMES) in the lower limb within the last 3 months

Participant randomization will be performed using a computer-generated random sequence. Allocation concealment will be ensured using opaque, sealed, and sequentially numbered envelopes, which will be opened only at the time of the intervention. The outcome assessor will remain blinded to group allocation to minimize bias during data collection.