There is provided an implantable pressure monitor having a fluid sack in contact with a body part of a patient where the fluid sack is retained to the body part by a pressure monitor housing that may have various attachment means. The fluid sack is filled with a liquid such as silicone oil. The pressure monitor housing has an opening that provides access to a fistula with a fluid valve that terminates through the fluid sack. A fiber optic pressure sensor is in contact with the liquid in the fluid sack by way of the fistula and fluid valve. In some embodiments of the present invention, an electronics module is incorporated with the implantable pressure monitor to provide telemetry, power, and the like.