Illness Perception and Treatment Expectations in Lateral Elbow Pain

Primary outcomes

• Illness perception (Brief Illness Perception Questionnaire, B-IPQ) [Single assessment at enrollment (Day 1)]: The B-IPQ is a 9-item self-report instrument assessing cognitive and emotional representations of illness. Eight items are rated on a 0 to 10 numeric scale covering consequences, timeline, personal control, treatment control, identity, concern, coherence and emotional representation; the ninth item is open-ended and asks about perceived causes. The total score ranges from 0 to 80, with higher scores indicating a more threatening perception of the illness.
• Treatment expectation (Treatment Expectation Questionnaire, TEX-Q) [Single assessment at enrollment (Day 1)]: The TEX-Q assesses expectations of an upcoming treatment. Fifteen scored items are rated on an 11-point scale from 0 (no expectation at all) to 10 (expecting complete recovery from treatment); six additional items are not included in scoring. Higher scores indicate higher treatment expectation.

Secondary outcomes

• Pain intensity (Numeric Rating Scale, NRS) [Single assessment at enrollment (Day 1)]: Self-reported lateral elbow pain intensity rated from 0 (no pain) to 10 (worst imaginable pain). Higher scores indicate greater pain intensity.
• Pain self-efficacy (Pain Self-Efficacy Questionnaire, PSEQ) [Single assessment at enrollment (Day 1)]: Ten items rated on a 7-point Likert scale (0 = not at all confident, 6 = completely confident), giving a total score of 0 to 60. Higher scores indicate greater confidence in performing activities despite pain.
• Fear-avoidance beliefs (Fear-Avoidance Beliefs Questionnaire, FABQ) [Single assessment at enrollment (Day 1)]: Sixteen items rated on a 7-point Likert scale from 0 (completely disagree) to 6 (completely agree), assessing beliefs about the effect of physical activity and work on pain. Higher scores indicate stronger fear-avoidance beliefs.
• Pain catastrophizing (Pain Catastrophizing Scale, PCS) [Single assessment at enrollment (Day 1)]: Thirteen items with helplessness, magnification and rumination subscales, each rated from 0 (never) to 4 (all the time), giving a total score of 0 to 52. Higher scores indicate greater pain catastrophizing.
• Elbow pain and function (Patient-Rated Tennis Elbow Evaluation, PRTEE) [Single assessment at enrollment (Day 1)]: Fifteen items covering pain (5 items) and function (6 specific activity items and 4 usual activity items) over the past week. The total score ranges from 0 to 100, with higher scores indicating greater pain and loss of function.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Aged 18 years or older
* Diagnosis of lateral epicondylalgia or lateral elbow pain made by an orthopaedic surgeon or physiatrist
* Pain intensity of at least 4 on the Numeric Rating Scale
* Pain duration of at least 12 weeks (chronic)
* Willing to provide written informed consent

Exclusion Criteria:

* History of any surgical procedure of the upper extremity
* Cervical spine pathology
* Inflammatory arthritis affecting the wrist or finger joints (e.g. rheumatoid arthritis)
* Active neurological disease or radiculopathy radiating to the upper extremity
* Diagnosis of fibromyalgia or another widespread pain syndrome
* Currently receiving active psychiatric treatment (e.g. psychosis, severe depression)
* Pregnancy
* Visual or cognitive impairment of a degree that would prevent completion of the questionnaires

• Hasan Gercek, PhD, Principal investigator, Acibadem University