Abstract: A measurement system measures a parameter of a muscular-skeletal system. The measurement system is placed in proximity to the muscular-skeletal system such that the parameter to be measured is applied to a sensing assemblage (3). The measurement system further comprises a digital counter (20), a digital timer (22), a digital clock 24, and a data register (26). The digital counter (20) is preset to a predetermined number of measurement cycles. The digital timer (22) measures an elapsed time of a measurement sequence comprising the predetermined number of measurement cycles. The digital counter (20) is decremented each measurement cycle until a zero count is reached thereby stopping the measurement sequence. The digital timer (22) measures an elapsed time of the measurement sequence. The parameter value can be related to the elapsed time. The precision of a parameter measurement can be modified by changing the predetermined number of measurement cycles.

Abstract: A sensor system uses positive closed-loop feedback to provide energy waves into a medium. It comprises a transducer (604), a propagating structure (602), and a transducer (606). A parameter is applied to the propagating structure that affects the medium. A sensor is coupled to a propagation tuned oscillator (416) that forms a positive closed-loop feedback path. The propagation tuned oscillator (416) includes a zero-crossing receiver (200) that generates a pulse upon sensing a transition of an energy wave from the propagating structure (602). The zero-crossing receiver (200) is in the feedback path that maintains the emission of energy waves into the propagating structure (602). The zero-crossing receiver (200) comprises a preamplifier (206), a filter (208), an offset adjustment circuit (210), a comparator (212) and a pulse circuit (218). The transit time, phase, or frequency is measured of the propagating energy waves and correlated to the parameter being measured.

Abstract: A measurement system for capturing a transit time, phase, or frequency of energy waves propagating through a propagation medium is disclosed. The measurement system comprises two different closed-loop feedback paths. The first path includes a transducer driver (726), a transducer (704), a propagation structure (702), a transducer (706), and a zero-crossing receiver (740). The transducer driver (726) efficiently drives the transducer (704) and comprises a digital driver (106), a level shifter (112), and a matching network (114). A second path includes a transducer driver (1126), a transducer (1104), a propagation medium (1102), a reflecting surface (1106), and an edge-detect receiver (1140). Energy waves in the propagating medium (1102) are reflected at least once. The edge-detect receiver (1140) detects a wave front of an energy wave. Each positive closed-loop path maintains the emission, propagation, and detection of energy waves in the propagation medium.

Abstract: A sensing insert device (100) is disclosed for measuring a parameter of the muscular-skeletal system. The sensing insert device (100) can be temporary or permanent. Used intra-operatively, the sensing insert device (100) comprises an insert dock 202 and a sensing module 200. The sensing module (200) is a self-contained encapsulated measurement device having at least one contacting surface that couples to the muscular-skeletal system. The sensing module (200) comprises one or more sensors (303), electronic circuitry (307), a capacitor (1410), and communication circuitry (320). The electronic circuitry (307) operatively couples to the one or more sensors (303) to measure the parameter. A transmitter (309) transmits parameter measurements. The capacitor (1410) can store sufficient charge to power the sensing module (200) for a total joint reconstruction operation. Energy is wirelessly coupled to an induction coil (1404) thereby generating a power signal that provides charge to the capacitor (1410).

Abstract: 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.

Abstract: A sensor system uses positive closed-loop feedback to provide energy waves into a medium. A sensor comprises a transducer (604), a propagating structure (602), and a reflecting surface (606). A parameter is applied to the propagating structure that affects the medium. The sensor is coupled to a propagation tuned oscillator (416) that forms the positive closed-loop feedback path with the sensor. The propagation tuned oscillator (416) includes an edge-detect receiver (200) that generates a pulse upon sensing a wave front of an energy wave in propagating structure (602). The edge-detect receiver (100) is in the feedback path that continues emitting energy waves into the propagating structure (602). The edge-detect receiver (200) comprises a preamplifier (212), a differentiator (214), a digital pulse circuit (216), and a deblank circuit (218). The transit time, phase, or frequency is measured of the propagating energy waves and correlated to the parameter being measured.

Abstract: A sensing insert device (100) is disclosed for measuring a parameter of the muscular-skeletal system. The sensing insert device (100) can be temporary or permanent. The sensing module (200) is a self-contained encapsulated measurement device having at least one contacting surface that couples to the muscular-skeletal system. The sensing module (200) comprises one or more sensing assemblages (2302), electronic circuitry (307), an antenna (2302), and communication circuitry (320). The sensing assemblages (2302) are between a top plate (1502) and a bottom plate (1504) in a sensing platform (121). The bottom plate (1504) is supported by a ledge (1708) on an interior surface of a sidewall (1716) of a housing (1706). A cap (1702) couples to top plate (1502). The sensing assemblage (2302) includes one of a piezo-resistive sensor, MEMS sensor, strain gauge, or mechanical sensor when a force, pressure, or load is applied to the top plate (1502).

Abstract: A sensing insert device (100) is disclosed for measuring a parameter of the muscular-skeletal system. The sensing insert device (100) can be temporary or permanent. Used intra-operatively, the sensing insert device (100) comprises an insert dock (202) and a sensing module (200). The sensing module (200) is a self-contained encapsulated measurement device having at least one contacting surface that couples to the muscular-skeletal system. The insert dock (202) is a passive component made for different prosthetic component manufacturers as well as for different size prosthetic components. The sensing module (200) fits in an opening or cavity of the insert dock (202). The intra-operative insert device is substantially equal in dimension to an implanted final insert. The sensing insert device (100) is also a permanent prosthetic component. The sensing module (200) residing within the sensing insert device and coupling to a bearing surface of the insert.