A prosthetic device having a socket with an insert having a bladder system for monitoring and compensating for volume fluctuations in a residual limb is provided. A plurality of bladders are preferably provided, in one embodiment, substantially only on a posterior portion of the socket. The bladders may be organized into zones, with the zones being inflatable to differing pressures depending on volume fluctuations in a residual limb. Pressure sensors may be provided for each bladder or for each zone, and flow regulators may be provided to control fluid flow into or out of the bladders or zones of bladders based on readings from the pressure sensors to control volume within the insert. Alternatively, bladders can be manually inflated depending on an amputee's needs.