Pressure Pain Threshold in Musculoskeletal Disorders

Abstract

Objective: Pain is the most significant symptom in musculoskeletal disorders. In this study we compared pressure pain threshold (PPT) values in patients with different musculoskeletal disorders in order to assess the pain response to mechanical stimulus. Materials-Methods: Patients diagnosed with ankylosing spondylitis (n=34), fibromyalgia (n=30), myofascial pain syndrome (n=33), osteoporosis (n=34), generalized osteoarthritis (n=34) and rheumatoid arthritis (n=34) and healthy subjects (n=30) were included in the study. The Beck depression inventory was used for psychological evaluation. Visual analog scale (VAS) was used to quantify pain. PPT was measured in the pain free areas of the body; at middle deltoid, middle ulna, hypothenar eminence, thumb, mid-tibia, and quadriceps femoris muscle. Results: VAS score for pain ranged from 4.76±3.15 in ankylosing spondylitis to 7.44±2.42 in fibromyalgia. Fibromyalgia consistently had the lowest PPT across all sites of measurements indicating increased pain sensitivity, while patients with myofascial pain syndrome had a high PPT. Myofascial pain syndrome and ankylosing spondylitis were the only diseases that did not show greater sensitivity to pain compared to healthy controls. Osteoporosis patients also reported an average clinical pain of 6.09±3.23 on VAS, and showed general tenderness regardless of presence of fractures. Overall, female gender, advanced age, depression and NSAID use correlated with lower PPT. A weak negative correlation was detected between VAS and PPT. Conclusion: In conclusion, the level of pain sensitivity may provide novel clues regarding the mechanism and treatment options of musculoskeletal disorders.