Ultrasonographic evaluation of muscle thickness in female patients with fibromyalgia and its relationship with clinical parameters.

Objective: The aim of this study was to compare the ultrasonographic thickness of selected major muscles of patients with fibromyalgia syndrome (FMS) and asymptomatic control subjects and to evaluate the relationship between muscle thickness and muscle strength, physical performance, kinesiophobia, and clinical variables.

Methods: Twenty-two FMS patients and 18 asymptomatic control cases who applied to the physical medicine and rehabilitation outpatient clinic were included. The thickness of the gastrocnemius medialis/lateralis, trapezius, and upper arm muscle was evaluated with ultrasonography. Muscle strength was evaluated with hand grip strength, muscle performance with chair stand test (CST), walking performance with 10 m walking test, disease severity with Fibromyalgia Impact Questionnaire-Revised, pain severity with VAS, and kinesiophobia with TAMPA kinesiophobia scale.

Results: The mean thickness values of all the muscles measured were significantly decreased in the FMS group compared with the control (p<0.05). There were positive correlations between gastrocnemius medialis/lateralis and upper arm muscle thickness with hand grip strength (p<0.01, r=0.602, r=0.663, r=0.567, respectively) and positive correlations between gastrocnemius medialis/lateralis muscle thickness with CST (p<0.05, r=0.507, r=0.512, respectively). TAMPA was significantly negatively correlated with gastrocnemius medialis/lateralis and upper arm muscle thickness.

Conclusion: Muscle thickness, strength, and performance decrease in FMS patients. This reduction in muscle strength, performance, and size is associated with kinesiophobia. Strengthening exercises should be included in the management of FMS patients. However, caution should be exercised when prescribing exercises that require extreme muscle performance, considering that it may cause kinesiophobia.