The Effectiveness of High-intensity Laser Therapy on Post-surgical Rehabilitation After Total Knee Arthroplasty

Visual Analogue Scale

The VAS consists of a 100-mm horizontal line anchored by two descriptors: "no pain" (0 mm) and "worst imaginable pain" (100 mm). Participants will be asked to mark a point on the line corresponding to their perceived level of pain. The score will be determined by measuring the distance in millimeters from the left end of the line to the patient's mark, with higher scores indicating greater pain intensity.

Time frame: Baseline, after 1 week, after 2 weeks, after 4 months follow-up

Range of Motion

Knee range of motion (ROM) will be assessed bilaterally, both actively and passively, including maximum flexion and full extension. Measurements will be obtained using a digital goniometer. The axis of rotation will be aligned with the lateral femoral condyle. The stationary arm will be aligned with the longitudinal axis of the femur, using the greater trochanter as a proximal reference point, while the movable arm will be aligned with the longitudinal axis of the fibula, using the fibular head and lateral malleolus as reference points. ROM values will be recorded in degrees, with higher flexion values and lower extension deficits indicating better joint mobility.

Time frame: Baseline, after 1 week, after 2 weeks, after 3 weeks, after 4 months follow-up

Swelling

Knee swelling will be assessed using circumferential measurements (cm) obtained with a flexible measuring tape. Measurements will be performed with the participant in the supine position and the lower limbs in full extension. Circumference will be recorded at standardized anatomical landmarks: 1 cm below the inferior pole of the patella (knee joint line), 10 cm and 20 cm above the patellar base, and 5 cm below the patellar apex. Two measurements will be taken at each site, and the mean value will be used for analysis. Higher circumference values will indicate greater swelling.

Time frame: Baseline, after 1 week, after 2 weeks, after 3 weeks, after 4 months follow-up

Lower limb muscle strength

Lower limb muscle strength will be assessed using a handheld dynamometer during isometric knee extension and flexion of the operated limb. Participants will perform three maximal voluntary isometric contractions for each movement, each lasting 5 seconds, with a 30-second rest interval between repetitions. The mean value of the three trials will be used for analysis. For knee extension assessment, participants will be seated with the hip and knee flexed at 90°. For knee flexion assessment, participants will be positioned prone with the knee flexed at 90°. In both conditions, limb positioning will be standardized using a digital goniometer and stabilized with a fixation strap. The dynamometer will be placed at the distal third of the leg, approximately 10 cm proximal to the ankle joint. The device will be manually stabilized by the assessor to ensure consistent positioning and minimize compensatory movements. Higher values will indicate greater muscle strength.

Time frame: Baseline, after 1 week, after 2 weeks, after 3 weeks, after 4 months follow-up

Western Ontario and McMaster Universities Osteoarthritis Index

The WOMAC is a patient-reported outcome measure specifically designed for individuals with knee osteoarthritis. It consists of three subscales assessing pain, stiffness, and physical function. The physical function subscale includes items related to activities of daily living such as walking, stair use, sitting, and standing. Each item is scored on a Likert scale, and total scores are calculated by summing item responses. Higher scores indicate worse pain, stiffness, and functional limitation.

Time frame: Baseline, after 1 week, after 2 weeks, after 3 weeks, after 4 months follow-up