Abstract: A prosthetic device (10) suitable for use in the treatment of stress incontinence in women by location as a cuff around the urethra, to elevate the bladder following prolapse, comprises a body (11) composed predominantly of a cross-linked synthetic polymer hydrogel having a water content of the order of 90%, and preferably about 95%, by weight. The hydrogel can be homogeneous through the body but in this event the body suitably has a local reinforcement (12), such as by embedded plastics material mesh, in at least one relatively small edge portion to enhance its tear resistance in relation to sutures (13) passed therethrough. The body is suitably of kidney shape having dimensional proportions of approximately 5.times.3.times.1. cms.