The Effect of Proprioceptive Neuromuscular Facilitation and Tendon Vibration After Total Knee Arthroplasty

Primary outcomes

1. Changes in neck pain intensity with Numeric Pain Rating Scale (NPRS)

   Time frame: pre-treatment, week 6, 6-month follow-up

   This tool is an eleven-point pain scale numbered from zero to 10. The left end of the scale corresponds to zero and is marked as "No pain", whereas the right end corresponds to 10 and is marked as "Maximum pain". Consequently, a higher value indicates more intense pain (Childs et al, 2005). The examinee is asked to choose an integer that best reflects the intensity of their pain. The NPRS is widely used to measure pain in both clinical practice and research, showing high test-retest reliability and high conceptual construct validity.

2. Changes in active Range of Motion (active ROM) of the knee joint flexion

   Time frame: pre-treatment, week 6, 6-month follow-up

   Active range of knee flexion will be assessed with a long arm goniometer. The measurement will be performed with the subject supine on the examination bed based on the instructions by Hancock et al. (2018), according to whom, measurement with a long arm goniometer shows very high reliability. Three consecutive bends will be requested from the examinee and the highest measured value will be recorded.

3. 3. Changes in functional capacity with the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire

   Time frame: pre-treatment, week 6, 6-month follow-up

   The KOOS questionnaire is a self-report tool for assessing functional limitations related to knee injuries or osteoarthritis (Roos et al., 1998). It is used in both research to assess functional ability and in clinical practice. The questionnaire includes 42 questions divided into five subscales: knee pain (KOOS pain), other knee symptoms (KOOS symptoms), functional limitations (KOOS ADL), ability to participate in sports or leisure activities (KOOS Sport/Rec), and quality of life (KOOS QOL). A five-point Likert scale from 0 (No problems) to 4 (Extreme problems) is used to score the questionnaire. Each of the KOOS subscales is scored separately, representing different aspects of the functional limitations experienced by the patient. The score for each subscale is converted to a 100-point scale, where a higher score indicates fewer functional limitations.

4. Changes in quality of life with Western Ontario and McMaster Universities Arthritis (WOMAC) index

   Time frame: pre-treatment, week 6, 6-month follow-up

   The WOMAC index is widely used in the assessment of the quality of life of people with osteoarthritis of the hip and knee (Salafi et al. 2005). It is a self-report questionnaire consisting of 24 questions classified into three subscales: Pain, knee joint stiffness and functional ability in everyday skills.Test questions are scored on a scale of 0 to 4. Scores for each subscale are summed, with a possible score range of 0-20 for pain, 0-8 for stiffness, and 0-68 for functional ability. A sum of the scores for all three subscales gives a total WOMAC score. The higher the score, the less functional the joint.The internal consistency of the subcategories of the Greek WOMAC version ranges from high (0.804) to excellent (0.956), while the intra-class correlation coefficients for test-retest reliability have been characterized as excellent (ranging between 0.91 - 0.95) (Papathanasiou et al. 2015).

5. Changes in Timed Up and Go test

   Time frame: pre-treatment, week 6, 6-month follow-up

   It is a simple test used to assess a person's mobility. It requires both static and dynamic balance and is a valid and reliable indicator of the functional ability of an individual (Podsiadlo & Richardson, 1991). The participant starts in a seated position. They then stand up following the instructions of the therapist, walk three meters, turn around, walk back to the chair and sit down. The examiner tracks time using a stopwatch. Time is calculated in seconds. A higher score indicates lower functional ability of the participant. The TUG shows high reliability indices in older adults both in measurements by different examiners and in measurements by the same examiner at different times (Cameron and Monroe, 2007).

6. Changes in Berg Balance scale Test

   Time frame: pre-treatment, week: 3, 6, 6-month follow-up

   The Berg Balance Scale is a tool proposed by Berg (Berg et al., 1989; Berg et al., 1992) for assessing balance in the elderly. The test involves the execution of 14 tests of gradual increasing difficulty where in each one, the subject is asked to maintain a given position for a specific time or conduct specific tasks. Each of the 14 tests on the list is graded according to the balancing ability of the examinee from 0 to 4 points (with 0 indicating low balance ability, while 4 indicates high balance ability). According to Berg et al. (1992), a score of 56 indicates functional balance, whereas a score lower than 45 indicates notable balance deficits that have been related to increased fall risk. Studies have shown high intra-rater and inter-rater reliability in the elderly populations with intraclass correlation (ICC) ranging from .98 to .88 (Berg et al. 1992) and high content validity (Telenius et al., 2015).

7. Changes of center of mass (COM) displacement

   Time frame: pre-treatment, week 6, 6-month follow-up

   Changes in COM displacement will be recorded using static posturography based on the protocol of Brech et al. (2022). Participants will remain barefoot and static for one minute while standing at ease on the force platform with feet shoulder-width apart, gazing at a target placed 2 meters away. Three attempts will be performed with one-minute intervals in between. The same procedure will be repeated with eyes closed. Parameters for measuring static balance under both conditions (eyes open and eyes closed) will include the root mean square of the displacement from the center of pressure (COP) in the mediolateral and anteroposterior directions. Additionally, the maximum range of COP displacement (sum of maximum and minimum displacement/amplitude) in these directions, and the mean velocity from the total COP displacement in all directions will be considered. For calculating the COP displacement area, values representing 95% of the total displacement ellipse will be used.

8. Chances in knee joint position sense

   Time frame: pre-treatment, week 6, 6-month follow-up

   Joint position sense will be calculated using the repositioning knee joint test according to the protocol of Relph and Herrington (2015). The joint position sense will be evaluated at two angles: 30° and 60°, with the knee moving from full extension (180°) to 90° flexion and vice versa. For the target angles, the participant will be required to replicate the specified angles.