SYSTEM AND METHOD FOR ORTHOPEDIC LOAD SENSING INSERT DEVICE
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 ) is included in a final insert for taking parameter measurements post-operatively. The sensing module ( 200 ) comprises one or more sensing assemblages ( 1802 ), electronic circuitry ( 307 ), an antenna ( 2302 ), and communication circuitry ( 320 ). The sensing insert device ( 100 ) is placed between a final femoral prosthetic component and a final tibial prosthetic component. Measurements are taken at more than one position of the range of motion. The load, balance, and applied location of the parameter can be determined by measurements from sensing module ( 200 ).
1 . A measurement system for measuring a parameter of the muscular-skeletal system comprising:
a sensing platform comprising:
a contacting surface; and
at least three sensing assemblages coupled to the contacting surface at predetermined locations and where a location where the parameter is applied to the contacting surface is determined from the parameter measurements of the at least three sensing assemblages.
2 . The measurement system of claim 1 where the sensing platform is in a sensing module and where the sensing module comprises:
at least one printed circuit board with electronic circuitry mounted thereto;
a flexible interconnect coupling the electronic circuitry and the at least three sensing assemblages; and
an encapsulating enclosure enclosing the sensing platform, printed circuit board, and flexible interconnect.
3 . The measurement system of claim 2 where the printed circuit board underlies the sensing platform in the encapsulating enclosure.
4 . The measurement system of claim 2 where the encapsulating enclosure comprises:
a housing; and
a cap overlying an opening of the housing where the cap is sealed to the housing, where the cap couples to the contacting surface of the sensing platform, and where the cap moves when a force, pressure, or load is applied thereto.
5 . The measurement system of claim 4 where the sensing platform is supported by at least one support structure of the housing.
6 . The measurement system of claim 1 further including:
electronic circuitry comprising:
operational circuitry operatively coupled to the at least three sensing assemblages;
power management circuitry operatively coupled to the operational circuitry;
communication circuitry coupled to the operational circuitry to wirelessly transmit measured parameter data; and
a power source operatively coupled to the electronic circuitry.
7 . The measurement system of claim 6 where the electronic circuitry is an application specific integrated circuit.
8 . The measurement system of claim 1 where a sensing assemblage comprises:
a waveguide; and
at least one transducer to emit energy waves in the wave guide and to detect propagated energy waves where the measurement system measures a frequency, transit time, or phase of the propagated energy waves.
9 . The measurement system of claim 1 further including an insert that includes the sensing platform where the insert is used intra-operatively and where the insert is substantially equal in dimensions to a final insert.
10 . The measurement system of claim 9 where the insert comprises a dock and the sensing platform.
11 . The measurement system of claim 1 further including a final insert that includes the sensing platform.
12 . A measurement system for measuring a force, pressure, or load applied by the muscular-skeletal system where a prosthetic component includes a sensing module and where the sensing module includes an elastic member to return a sensing platform to a predetermined position under quiescent conditions.
13 . The measurement system of claim 12 where the sensing module includes:
a contacting surface;
a support structure;
a sensing assemblage coupled between the contacting surface and the support structure;
electronic circuitry operatively coupled to the sensing assemblage; and
at least one spring as the elastic member coupled between the contacting surface and the support structure.
14 . A method of measuring a parameter of a knee joint comprising the steps:
installing a final tibial prosthetic component;
installing a final femoral prosthetic component; and
inserting a trial insert between the final tibial and femoral prosthetic component where the insert includes a sensing module for measuring the parameter and where the trial insert is substantially equal in dimensions to a final insert.
15 . The method of claim 14 further comprising the steps of:
selecting a dock having a major surface that fits the final tibial prosthetic component a the dock height corresponds to bone cuts made to install the final tibial and femoral prosthetic components;
inserting a sensing module in the dock where the trial insert comprises the dock and the sensing module;
measuring a force, pressure, or load of the knee joint; and
removing the trial insert from the knee joint if a load measurement is greater than a predetermined value or less than a predetermined value.
16 . The method of claim 15 further including the steps of:
removing the sensing module from the dock;
selecting a dock having a new height;
inserting the sensing module in the dock having the new height; and
inserting the trial insert in the knee joint.
17 . The method of claim 14 further including the steps of:
measuring a force, pressure, or load of the knee joint in one or more positions of a leg range of motion;
transmitting measurement data; and
adjusting the force, pressure, or load.
18 . The method of claim 17 further including the steps of:
measuring a force, pressure, or load in both knee compartments;
comparing the force, pressure, or load between the knee compartments; and
balancing the knee compartments.
19 . The method of claim 14 further including the steps of:
removing the trial insert from the knee joint; and
inserting the final insert in the knee joint.
20 . The method of claim 19 further including a step of measuring a parameter of the muscular-skeletal system with the final insert.