Background and aim
Recently, it has been shown that the contraction of the dynamic stabilizers, mainly First Dorsal Interosseus muscle (FDI), reduces the subluxation of the Thumb carpometacarpal joint (CMC) and thus the load on the joint leading to Osteoarthritis. No previous studies have examined the presence of the myofascial trigger point (MTrP) of FDI in patients with rhizarthrosis.The aim of this study was to investigate the presence of FDI MTrP in patients with rhizoarthrosis.
Methods
67 patients with rhizoarthrosis of the dominant hand were consecutively recruited. Pressure pain thresholds (PPTs) were assessed bilaterally over the Thumb CMC joint, FDI muscle and over the C5-C6 zygapophyseal joint. Intensity of pain (Visual analogue scale, VAS), Quick Disability of the Arm, Shoulder and Hand (Quick-DASH scale), pinch strength test were also measured bilaterally. The muscle was examined by a blinded assessor to establish the clinical conditions of the FDI following the international consensus on diagnostic criteria of MTrP.
Results
In patients with rhizoarthtrosis, prevalence of latent MTrP of the FDI was higher when compared with non-dominant hand (76.1% vs 47.7%). No significant difference on the average level of PPT over the FDI muscle and during pinch strength test were detected between dominant and non-dominant hand (P < 0.05).
Conclusions
A higher presence of latent MTrP of the FDI in the dominant hand of patients with rhizarthtrosis was found. Further researches should be conducted in order to establish if MTrP treatments improve hypersensivity in this population.

PAIN HYPERSENSIVITY AND MYOFASCIAL TRIGGER POINT OF THE FIRST DORSAL INTEROSSEUM MUSCLE IN PATIENTS WITH RHIZARTHROSIS