Lateral epicondylitis (LE) is a common musculoskeletal disorder characterized by pain and tenderness over the lateral elbow and may become chronic despite conservative treatment. Although LE is primarily associated with local tendon pathology, central sensitization, radial nerve involvement, and psychosocial factors may contribute to persistent pain and disability. This cross-sectional case-control study aims primarily to compare remote pressure pain thresholds between individuals with chronic LE and healthy controls. Secondary objectives are to compare clinical, functional, psychosocial, and ultrasonographic findings between the groups and to investigate the factors associated with functional impairment in individuals with chronic LE.
Lateral epicondylitis (LE), commonly known as tennis elbow, is a prevalent musculoskeletal disorder characterized by pain and tenderness over the lateral epicondyle. It is generally associated with repetitive mechanical loading, microtrauma, and degenerative changes affecting the common extensor tendon origin. Because LE may impair upper-extremity function, daily activities, and work productivity, it represents an important clinical and socioeconomic problem. Although conservative treatment is generally effective, symptoms may persist or become chronic in some individuals.The pathophysiology of chronic LE may extend beyond local tendon pathology. Emerging evidence suggests that altered nociceptive processing and central sensitization may contribute to persistent pain. Pressure pain threshold (PPT) assessment at both local and remote sites may help identify localized and widespread pressure pain hypersensitivity. The radial nerve may also be relevant because radial nerve entrapment and LE can produce overlapping clinical findings and may coexist. Ultrasonographic evaluation of both the common extensor tendon and radial nerve may therefore provide additional information about the peripheral components of the condition. Psychosocial factors, including pain catastrophizing, kinesiophobia, depressive symptoms, and anxiety, may also influence pain severity, functional impairment, and the development or maintenance of sensitization. Although these factors have been extensively investigated in chronic musculoskeletal pain, their combined relationships with pain sensitivity, functional status, and ultrasonographic findings in chronic LE remain insufficiently characterized. The primary objective of this cross-sectional case-control study is to compare remote PPT values between individuals with chronic LE and healthy controls. The secondary objectives are to compare local PPT, central sensitization, pain catastrophizing, kinesiophobia, depression, anxiety, functional status, radial nerve cross-sectional area, and common extensor tendon thickness between the groups. In the patient group, the study will also examine the relationships of functional status with local and remote PPT values, central sensitization, psychosocial factors, and ultrasonographic findings.
Study Type
OBSERVATIONAL
Enrollment
128
Pressure pain threshold is defined as the minimal pressure level that causes pain. The measurement will be applied twice for each region with a 1-minute interval, and the average of these applications will be recorded. A trial test will be conducted on the patient before the actual test. Pressure will be applied to selected points with a pressure algometer until pain is induced, and the test for that area will be terminated when the patient feels pain.
The cross-sectional area of the radial nerve will be measured in the antecubital fossa and the spiral groove. Three measurements will be taken for the nerve cross-sectional area, and the average will be calculated. For the measurement of common extensor tendon thickness, the probe will be placed over the lateral epicondyle, and the evaluation will be conducted with the elbow in 90 degrees of flexion and the forearm in mid-supination. The Sonosite M-Turbo device will be used for ultrasonography and will be performed by a rehabilitation specialist with 10 years of experience.
Sultan Abdülhamid Han Eğitim ve Araştırma Hastanesi
Istanbul, Turkey (Türkiye)
RECRUITINGPressure Pain Threshold (PPT)
The pressure pain threshold is defined as the lowest pressure level that causes pain. The measurement will be taken from the anterior-medial region of the tibia (a distant, painless, and irrelevant area) using a Wagner manual pressure algometer (1 cm² probe-10 kg/20 lb). The measurement will be applied twice at 1-minute intervals, and the average of these applications will be recorded. A trial test will be conducted on the patient before the actual test. Pressure will be applied to the selected points with a pressure algometer until pain is induced, and the test in that area will be terminated when the patient feels pain.
Time frame: Baseline
Central Sensitization Inventory
CSI scores range from 0-100, with higher scores indicating greater severity of central sensitization-related symptoms.
Time frame: Baseline
Tampa Scale for Kinesiophobia (TSK)
The TSK consists of a total of 17 items, and individuals evaluate each item using a 4-point Likert scale (1=strongly disagree, 4=strongly agree). The total score obtained from the scale reflects the individual's level of kinesiophobia. Increasing TSK scores indicate an increase in avoidance behaviors and fear related to pain.
Time frame: Baseline
Pain Catastrophizing Scale (PCS)
The PCS consists of a total of 13 items, and each item is evaluated on a 5-point Likert scale (0=never, 4=always). The total and subscale scores obtained from the scale reflect the individual's level of catastrophic thinking toward pain. High PCS scores indicate an increase in negative cognitive and emotional responses to pain.
Time frame: Baseline
Patient-Rated Tennis Elbow Evaluation
To evaluate upper extremity functionality, it is a questionnaire specifically designed for patients with lateral epicondylitis, providing patient follow-up and being condition-specific, with scoring ranging from 0 (no pain/disability) to 100 (possible worst pain and disability), and containing pain and function sub-scales. The total score is calculated out of 100 by summing the pain and function subscales. Low scores indicate better function.
Time frame: Baseline
Hospital Anxiety and Depression Scale
It is a 14-item self-report scale that quickly, reliably, and independently of medical conditions assesses patients' anxiety and depression symptoms over the past week.
Time frame: Baseline
short form-12
The health-related quality of life of the participants will be evaluated using the Short Form-12 (SF-12) Quality of Life Scale. SF-12 is a 12-item self-report scale that assesses individuals' physical function, physical role limitations, pain, general health perception, vitality, social function, emotional role limitations, and mental health status over the past four weeks. From the scale, the physical component score (Physical Component Summary, PCS) and the mental component score (Mental Component Summary, MCS) are obtained.
Time frame: Baseline
Pressure Pain Threshold - Local
Pressure pain threshold is defined as the minimal pressure level that causes pain. The measurement will be applied twice for each region with a 1-minute interval, and the average of these applications will be recorded. A trial test will be conducted on the patient before the actual test. Pressure will be applied to the selected point with a pressure algometer until pain is induced, and the test for that area will be terminated when the patient feels pain. The measurement will be taken from the symptomatic common extensor tendon area, and a Wagner manual pressure algometer (1 cm² probe-10 kg/20 lb) will be used.
Time frame: Baseline
Radial Nerve CSA (in spiral groove and antecubital fossa)
The cross-sectional area of the radial nerve will be measured in the antecubital fossa and spiral groove. In the spiral groove, the measurement will be taken with the patient's arm resting on the table, the elbow bent at 90°, the forearm in a pronation position, and the hand loosely resting on the table, with the probe perpendicular to the arm axis and placed on the lateral side of the distal third of the humerus. If measuring from the antecubital fossa, the patient will have their arm resting on the table, elbow extended, and forearm in a supine position; the probe will be placed transversely to the arm axis at the front of the elbow flexion, observing the elbow joint space. The radial nerve, located between the brachioradialis muscle and the anterior brachialis muscle, will be visualized before it divides into two branches. Two measurements will be taken for the nerve cross-sectional area, and the average will be calculated.
Time frame: Baseline
Common extansor tendon thickness
For the measurement of common extensor tendon thickness, the probe will be placed on the lateral epicondyle, and the evaluation will be conducted with the elbow in 90 degrees of flexion and the forearm in mid-supination. To determine the evaluation point, a horizontal line of 1 cm will be placed from the upper edge of the lateral epicondyle. At this point, a vertical line will be drawn from the upper edge of the tendon tissue to the hyperechoic line of the humerus for measurement. The Sonosite M-Turbo device will be used for ultrasonography and it will be performed by a physical therapy and rehabilitation specialist with 10 years of experience.
Time frame: Baseline
Grip Strength Measurement
It will be measured using a modified sphygmomanometer test (MST). a manual aneroid sphygmomanometer (gauge manometer + inflation bulb + cuff) will be used. First, the blood pressure measurement device will be transformed into a cylinder that the patient can comfortably grasp while resting. then the cuff will be inflated to 20 mmHg and the patient will apply maximum grip strength to the cuff. Grip measurements will be taken while the participant sits in a chair without armrests, with their feet supported, shoulders internally rotated, forearms in a neutral position, and elbows flexed at 90°. Before the assessment, information about the procedures and a trial will be conducted. They will be instructed to perform maximum isometric contraction for 5 seconds, and the highest force value (mmHg) will be recorded. The measurement will be taken 3 times with a 15-second rest interval, and the average will be calculated.
Time frame: Baseline
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