Subjective and objective evaluation of pain for older adults with knee osteoarthritis in Saudi Arabia: A reliability study

Aims: This study establishes the reliability and validity of pain pressure threshold (PPT) in evaluating pain for older adults with knee arthritis, and explores the importance of using a standard tool to measure pain in older adults. Methods: The study consisted of a group of 31 older adult patients with bilateral symptomatic knee osteoarthritis, intra- and inter-rater reliability, and concurrent validity that were assessed for PPT and were compared with standard visual analogue scale (VAS). Physical therapy intervention was provided to combat the pain. Results: The PPT showed excellent intra-assessor reliability by not only meeting acceptable standards but also representing very high values. The intra-assessor reliability between test sessions was excellent. The inter-assessor agreement was also very high before treatment. The highest ICC showed very good agreement (0.860) during the initial treatment for pain pressure measurement. The study also established concurrent validity of VAS and PPT (before treatment and after treatment), where the rho correlation was high (-0.708 and -0.625) and significant, indicating that PPT is adequately sensitive for detecting changes over time. Conclusion: PPT is a reliable and valid tool for measuring pain, and it helps clinicians understand the prognostic effect of the intervention, especially in older adults. The tool is consistent at measuring pain and is a valid tool compared to subjective pain scoring.