Knee osteoarthritis is one of the most common degenerative joint diseases and is associated with chronic pain, functional impairment, and reduced quality of life. Psychological factors may influence both symptom severity and response to treatment. Alexithymia, characterized by difficulty in identifying and expressing emotions, has been associated with poorer outcomes in chronic pain conditions.

The aim of this prospective observational study is to investigate whether the presence of alexithymia affects the clinical response to a standardized physical therapy program in patients with knee osteoarthritis. Participants will undergo a standard physical therapy regimen and will be evaluated before treatment, immediately after treatment, and 6 weeks after treatment completion. Pain, functional status, alexithymia, anxiety, and depression will be assessed using validated clinical scales. The study seeks to determine whether alexithymia is an independent predictor of treatment response in patients with knee osteoarthritis.

Detailed Description

Knee osteoarthritis (KOA) is one of the most prevalent degenerative musculoskeletal disorders and represents a major cause of chronic pain, disability, and reduced quality of life worldwide. Although structural joint degeneration is a hallmark of the disease, increasing evidence suggests that psychological factors also contribute to pain perception, functional impairment, and variability in treatment outcomes.

Alexithymia is a personality construct characterized by difficulty in identifying, describing, and expressing emotions. Previous studies have demonstrated that alexithymia is associated with greater pain severity, poorer functional status, and unfavorable clinical outcomes in various chronic pain conditions. However, its influence on the response to conservative treatment in patients with knee osteoarthritis has not been adequately investigated.

The primary objective of this prospective observational cohort study is to evaluate whether alexithymia influences the clinical response to a standardized physical therapy program in patients with knee osteoarthritis. The secondary objective is to determine whether alexithymia independently predicts treatment outcomes after adjustment for potential confounding factors.

Patients aged 40 to 75 years with clinically and radiographically diagnosed knee osteoarthritis will be enrolled. All participants will receive a standardized physical therapy program consisting of Transcutaneous Electrical Nerve Stimulation (TENS), superficial heat therapy (hot pack), therapeutic ultrasound, and a home exercise program over a three-week treatment period.

Clinical evaluations will be performed at baseline, immediately after completion of treatment, and six weeks after treatment completion. Pain severity will be assessed using the Visual Analog Scale (VAS), functional status using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), alexithymia using the Toronto Alexithymia Scale-20 (TAS-20), and anxiety and depression using the Hospital Anxiety and Depression Scale (HADS). Participants will be classified as alexithymia-positive or alexithymia-negative according to their baseline TAS-20 scores.

The primary outcome measure will be the change in WOMAC total score. Secondary outcome measures will include changes in VAS and HADS scores. Multivariable regression analyses will be performed to determine whether alexithymia is an independent predictor of response to physical therapy after adjustment for demographic and clinical variables.

Inclusion Criteria:

Age between 40 and 75 years. Diagnosis of knee osteoarthritis according to the American College of Rheumatology (ACR) criteria.

Kellgren-Lawrence grade II or III on radiographic evaluation. Presence of symptomatic knee pain requiring physical therapy. Willingness and ability to participate in the standardized physical therapy program.

Ability to complete study questionnaires and clinical assessments. Provision of written informed consent prior to participation.

Exclusion Criteria:

Age younger than 40 years or older than 75 years. Kellgren-Lawrence grade I or grade IV knee osteoarthritis. Previous knee arthroplasty or major knee surgery on the affected side. Lower extremity surgery within the previous 6 months. Intra-articular corticosteroid, hyaluronic acid, platelet-rich plasma, prolotherapy, or stem cell injection into the knee within the previous 3 months.

Physical therapy for knee osteoarthritis within the previous 3 months. Acute knee trauma or fracture. Inflammatory rheumatic diseases (e.g., rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis).

Fibromyalgia or chronic widespread pain syndrome. Active infection or malignancy. Neurological disorders significantly affecting lower extremity function or balance (e.g., stroke, Parkinson's disease, multiple sclerosis).

Severe cognitive impairment or major psychiatric illness that may interfere with study participation or questionnaire completion.

Contraindications to physical therapy modalities (TENS, therapeutic ultrasound, or superficial heat therapy).

Regular opioid analgesic use or other medications that may substantially influence pain perception.

Pregnancy or breastfeeding. Inability to comply with the treatment protocol or follow-up assessments. Participation in another interventional clinical study during the study period. Refusal or inability to provide written informed consent.

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The study population will consist of adult patients aged 40 to 75 years with clinically and radiographically confirmed knee osteoarthritis according to the American College of Rheumatology (ACR) criteria and Kellgren-Lawrence grade II or III disease. Participants will be recruited consecutively from the outpatient Physical Medicine and Rehabilitation Clinic of Kanuni Sultan Süleyman Training and Research Hospital. All eligible patients who meet the inclusion criteria and provide written informed consent will receive a standardized physical therapy program and will be prospectively followed to evaluate the effect of alexithymia on treatment response.

Not applicable, as Individual Participant Data (IPD) will not be shared.