Background and objective: Frozen shoulder syndrome (FSS) causes pain and restriction of movement in the shoulder. The aim was to assess changes in shoulder muscle isometric maximal voluntary contraction (MVC) force and active range of motion (AROM) in patients with frozen shoulder syndrome (FSS) after manipulation under general anesthesia (MUA).
Material and methods: In total, 18 patients with FSS (9 women and 9 men) with a mean age of 53.6 years (SD, 9.7) participated in this study. MVC force of shoulder flexors, adductors, and internal and external rotators was measured by a handheld dynamometer. AROM in the same directions was measured goniometrically. The patients were screened according to the intensity of pain by day and at night. The data were collected before MUA and 1 and 6 months after MUA. A significant reduction in MVC force and AROM was noted before MUA in the involved extremity as compared with the uninvolved extremity (P<0.05). These parameters for the involved extremity were significantly increased 1 month after MUA (P<0.05). However, 6 months after MUA, MVC force and AROM did not differ significantly compared with the uninvolved extremity (P>0.05), whereas AROM of flexion and external rotation remained significantly reduced (P<0.05). A significant reduction in shoulder pain by day and at night was recorded 1 and 6 months after MUA (P<0.05).
Conclusions: In the patients with FSS, the fastest improvement of MVC force and AROM occurred following the first month after MUA. However, 6 months after MUA, shoulder muscle MVC force for the involved extremity did not differ significantly as compared with the uninvolved extremity, whereas the shoulder AROM in flexion and external rotation remained lower.