A dual-mode closed-loop measurement system (100) for capturing a transit time, phase, or frequency of energy waves propagating through a medium (122) is disclosed. A first module comprises an inductor drive circuit (102), an inductor (104), a transducer (106), and a filter (110). A second module housed in a screw (335) comprises an inductor (114) and a transducer (116). The screw (335) is bio-compatible and allows an accurate delivery of the circuit into the muscular-skeletal system. The inductor can be attached and interconnected on a flexible substrate (331) that fits into a cavity in the screw (335). The first and second modules are operatively coupled together. The first module provides energy to power the second module. The second module emits an energy wave into the medium that propagates to the first module. The transit time of energy waves is measured and correlated to the parameter by known relationship.
