Sixty patients with unilateral frozen shoulder were randomized to receive ultrasound-guided intra-articular steroid injection (UG-IASI) (n = 30) or electrotherapy (ET) consisting of interferential therapy, short-wave diathermy, and therapeutic ultrasound (n = 30). The primary outcome of interest was SPADI (Shoulder Pain and Disability Index). Secondary outcomes included range of motion (ROM) across flexion, abduction, rotation, extension, and adduction. Outcomes were assessed at baseline, 1 month, 3 months, 6 months, and 1 year. Overall, the results revealed that UG-IASI produced significantly greater improvements in SPADI and ROM at 1, 3, and 6 months (all P < 0.05), with differences narrowing by 1 year. Diabetic patients in both groups showed attenuated recovery. These findings suggest that UG-IASI provides superior early and mid-term functional recovery, supporting its use as an early targeted intervention in frozen shoulder.