Clinical Research Directory

Inclusion Criteria: * Age 18 years or older. * Native Turkish speaker or able to read and understand Turkish fluently. * Diagnosed with primary hip osteoarthritis based on clinical and radiographic evaluation. * Scheduled to undergo primary total hip arthroplasty. * Able to complete the study questionnaires independently or with standardized assistance. * Clinically stable during the test-retest period. * Willing to participate in the study and provide written informed consent. Exclusion Criteria: * Previous total hip arthroplasty on the affected side. * Scheduled for revision hip arthroplasty. * Hip arthroplasty indicated for conditions other than primary hip osteoarthritis, including hip fracture, inflammatory arthritis, avascular necrosis, congenital hip disorders, or malignancy. * History of major lower-extremity surgery within the previous six months. * Neurological or neuromuscular disorders that may substantially affect mobility or lower-extremity function. * Severe cognitive impairment, psychiatric disorder, or communication difficulty that prevents reliable questionnaire completion. * Severe visual or hearing impairment that prevents completion of the assessment procedures. * Presence of another acute musculoskeletal condition that substantially affects pain or physical function. * Any therapeutic intervention, significant change in medication, acute clinical deterioration, or surgery occurring between the baseline and test-retest assessments. * Incomplete questionnaire data or inability to complete the planned follow-up assessments.