Assessment of Isokinetics and Range of Motion of the Shoulder in Patients after Reverse Shoulder Arthroplasty in the Late Follow-Up Period

(1) Background: The aim of the study was to evaluate the peak torque (PT) in isokinetic conditions and the range of motion of the shoulder joint in patients after reverse total shoulder arthroplasty in the late treatment period. (2) Methods: The study included fifteen patients aged 60-70 years (13 women and 2 men). The comparison group consisted of 15 healthy subjects (12 women and 3 men) aged 60-69 years. The study included measurement of peak torque (PT) and the range of motion of the shoulder joint, assessed using the Biodex System 4 Pro set, and an electronic goniometer. We conducted tests at two different angular velocities (60 degrees/s and 90 degrees/s), taking into account the operated and non-operated limb and comparing the results to healthy subjects. The average time from surgery to functional examination was 16 months. (3) Results: The non-operated limb generated significantly higher PT values than the operated limb (p < 0.001). The healthy limb of patients from the comparison group generated significantly higher PT values than the operated limb of patients from the study group (p < 0.001). A significant improvement (p < 0.001) in the range of motion in the operated limb was achieved after rTSA. (4) Conclusions: In patients 18 months after the rTSA, the non-operated upper limb has significantly greater muscle strength in flexion/extension and abduction/adduction movements compared to the operated limb. The non-operated limb also has a significantly greater range of motion compared to the operated limb.