Osteopathy therapy for pelvic stiffness. Therapist using osteopathy techniques on a 12-year-old boy's pelvis and lower back. Osteopathy uses massage and manipulation to treat a range of disorders, based on knowledge of the musculoskeletal system. Here, manipulation is being used to unlock the pelvis and the vertebrae of the lower back. This increases the mobility of stiff joints, such as the hips and the lower part of the backbone.