Effectiveness of warm water immersion therapy for reducing morning stiffness in mild osteoarthritis patients

Abstract

Osteoarthritis (OA) is a prevalent degenerative joint disorder characterized by articular cartilage breakdown, subchondral bone changes, and synovial inflammation, frequently resulting in joint pain, stiffness particularly in the morning and functional disability in older adults. Non pharmacologic interventions have increasingly focussed on water based therapies, where warm water immersion (WWI) may confer improved joint mobility and reduced stiffness through mechanisms such as thermal vasodilation, increased perfusion, and muscle relaxation. Despite evidence for aquatic exercise and hydrotherapy in OA management, data targeting morning stiffness in mild OA and isolating the effect of passive warm water immersion are limited. The present article addresses this gap by investigating the effectiveness of WWI in reducing early morning joint stiffness among patients with mild OA. Specifically, the research aims to evaluate whether daily immersion in warm water over a four week period significantly reduces self reported morning stiffness duration and improves joint mobility compared to standard care. The primary objective is to quantify the reduction in morning stiffness duration; secondary objectives include assessing changes in pain levels, joint range of motion, and patient reported functional capacity. The working hypothesis is that patients receiving daily warm water immersion will exhibit a statistically significant reduction in morning stiffness duration (≥20 %) and improvements in secondary outcomes, relative to controls receiving standard advice only. The findings may support WWI as a simple, low cost adjunctive therapy to alleviate morning stiffness in mild OA.