Initial and Continuous Effects of Essential Oil Therapy in Relieving Knee Pain Among Older Adults With Osteoarthritis.

Background: For older adults, osteoarthritis (OA) is a common chronic disease that may cause pain, stiffness, and even disability of the affected knee joints. Aromatherapy might presumed to be an alternative and supplemental therapy.

Primary Study Objective: To investigate the effects of aromatherapy on relieving knee pain and improving physical functions among older adults with OA.

Methods/design: A true experimental design with randomized assignment of both treatment (aromatherapy) and control (placebo) groups was used for this study.

Participants: Volunteers from 3 local communities aged ≥50 y with self-reported OA-related knee pain were recruited.

Interventions: A synergistic blend of essential oils diluted to a concentration of 3% was administered to participants in treatment (essential oil) group, whereas mineral oil without essential oil was applied to participants in control (placebo) group. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), including subscales of pain, stiffness, and physical function, was employed to record scores before intervention, 4 wk postintervention, and 8 wk postintervention. Pain scores were also measured and collected by using the visual analog scale at the above counterparts. The Stata v.13 software was used to perform referent statistics with a significance level (α) of 0.05 adopted.

Results: The progressive linear model showed that continuous use of essential oils for 8 wk not only relieves pain immediately, but also further reduces the pain scores of participants, thus proving the long-term effect of aromatherapy on alleviating knee arthritis. Repeated measures analysis of variance further showed that time (intervention duration) is an important factor affecting all outcome scores. Except for stiffness subscales measured by WOMAC, all interactions between groups were significant.

Conclusions: Aromatherapy is validated to be an effective alternative therapy in improving clinical outcomes for patients with OA-induced knee conditions. In addition, longer intervention duration (8 wk instead of 4 wk) yielded better treatment results for participants.