Device for assisting with the placement of an orthopedic instrument

Patent metadata

Field	Value
Publication number	US-10426541-B2
Application number	US-201514677050-A
Country	US
Kind code	B2
Filing date	Apr 2, 2015
Priority date	Apr 2, 2014
Publication date	Oct 1, 2019
Grant date	Oct 1, 2019

Abstract

A device (1) assisting with the placement of an orthopedic instrument (2) intended to be inserted in a receiving bone (3) by impaction, by means of an impacter (10) comprising at least one striking surface (11) designed to come into contact with an impact surface coupled to said orthopedic instrument in order to apply an impaction force to said orthopedic instrument (2), said device being characterized in that it comprises a force sensor (12) able to measure, upon each impact, said impaction force applied by the impacter (10) to said impact surface and to supply a measurement signal indicative of the temporal variation of said applied impaction force, said force sensor (12) being connected to processing means (30) designed to determine, on the basis of the temporal variation of said impaction force supplied for each impact in succession, an indicator representative of the degree of insertion of said orthopedic instrument (2) in the receiving bone (3).

First claim

The invention claimed is:

1. A device assisting with placement of an orthopedic instrument intended to be inserted in a receiving bone by impaction, said device comprising:
an impactor comprising at least one striking surface designed to impact an impact surface, coupled to an orthopedic instrument, to apply a first impaction force to said orthopedic instrument;
a force sensor that:
measures, upon a first impact, said first impaction force applied by the impactor to said impact surface,
supplies a first measurement signal, the first measurement signal comprising a first temporal variation of said first impaction force, the first temporal variation of the first impaction force being a first signal representative of the first impaction force over a first time duration, the first signal comprising a first plurality of points, wherein each point out of the first plurality of points along the first signal comprises a first amplitude value representative of the first impaction force and a first time value representative of an instant in the first time duration of the first measurement signal; and

a processor coupled to a memory, wherein the processor:
is connected to said force sensor,
receives the first measurement signal including the first temporal variation of the first impaction force,
calculates a first indicator representative of a degree of insertion of said orthopedic instrument in the receiving bone based on evaluation of the plurality of points in the first temporal variation after the first measurement signal is received, and
determines an accuracy of a level of insertion of the orthopedic instrument in the receiving bone based on the first indicator.

2. The device according to claim 1 , wherein:
the first indicator, calculated by the processor, comprises an arithmetic mean of the first amplitude values of the first plurality of points over a first time interval of programmable duration on said first measurement signal, and
a start of the first time interval is defined with respect to an instant corresponding to a maximum amplitude of the first measurement signal.

3. The device according to claim 2 , wherein the start of said first time interval coincides with the maximum amplitude of said first measurement signal.

4. The device according to claim 2 , wherein said first time interval has a duration of between 1.2 ms and 2 ms, inclusive.

5. The device according to claim 2 , wherein the start of said first time interval is defined with a first predetermined delay with respect to the instant corresponding to the maximum amplitude of said first measurement signal.

6. The device according to claim 5 , wherein said first time interval has a first predefined duration of less than or equal to 10 ms.

7. The device according to claim 2 , wherein said first indicator is calculated using the following equation:

I
1

=

1

A
1

·

(

t
2

-

t
1

)

⁢

∫

t
1

t
2

⁢

A
⁡

(
t
)

·

⁢
dt

where: A(t) corresponds to an amplitude of said first measurement signal at a first time instant t;
A1 corresponds to the maximum amplitude of said first measurement signal over the first time interval; and
T1 and t2 correspond respectively to the instant marking the start and an instant marking an end of said first time interval.

8. The device according to claim 1 , wherein the processor further:
tests a convergence of said first indicator toward a steady value as a function of a number of the first impact, and
determines said degree of insertion of said orthopedic instrument into the receiving bone based on the tested convergence of said first indicator.

9. The device according to claim 1 , further comprising a placement ancillary, wherein:
said orthopedic instrument consists of an orthopedic implant, and
said impactor impacts said orthopedic implant in collaboration with the placement ancillary consisting of a rigid manipulation handle including a distal part defining a head for holding said implant and with a proximal part defining said impact surface.

10. The device according to claim 1 , wherein said orthopedic instrument comprises an orthopedic implant surgical rasp comprising:
a part for holding, and
an upper end of said part for holding comprising said impact surface.

11. The device according to claim 1 , wherein said force sensor comprises an accelerometer.

12. The device according to claim 1 , wherein said force sensor is mounted on said at least one striking surface of said impactor.

13. The device according to claim 1 , wherein said force sensor is mounted on said impact surface.

14. The device according to claim 1 , wherein said force sensor comprises strain gauges.

15. The device according to claim 11 , wherein the surgical rasp comprises a femoral rasp for a hip prosthesis.

16. The device according to claim 1 ,
wherein the force sensor further:
measures, after supplying the first measurement signal and upon a second impact, a second impaction force applied by the impactor to the impact surface, and
supplies a second measurement signal, the second measurement signal comprising a second temporal variation of the second impaction force, the second temporal variation of the second impaction force being a signal representative of the second impaction force over a second time duration, the second signal comprising a second plurality of points,
wherein each point out of the second plurality of points along the second signal comprises a second amplitude value representative of the second impaction force and a second time value representative of an instant in the second time duration of the measurement signal; and

wherein the processor further:
stores the first indicator into the memory,
receives the second measurement signal,
calculates a second indicator based on the second plurality of points after the second measurement signal is received,
stores the second indicator into the memory,
performs a comparison between the second indicator and the first indicator, and
determines an accuracy of a level of insertion of the orthopedic instrument in the receiving bone based on the comparison.

Assignees

• Centre Nat Rech Scient

Inventors

• Haiat Guillaume
• Mathieu Vincent
• Michel Adrien

Classifications

• A61B90/06

  Measuring instruments not otherwise provided for · CPC title

• A61F2/4609

  of acetabular cups · CPC title

• A61F2002/4681

  by applying mechanical shocks, e.g. by hammering · CPC title

• A61F2/4657

  Measuring instruments used for implanting artificial joints (for surgical instruments A61B90/06) · CPC title

• A61F2002/4666

  for measuring force, pressure or mechanical tension · CPC title