SOUNDER FOR SIZING BONE IMPLANT

• US 20160345983A1
• Filed: 04/20/2016
• Published: 12/01/2016
• Est. Priority Date: 05/29/2015
• Status: Active Grant

• Current Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Wagner, Terry W.
• Granted Patent: US 10,441,297 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 17/164 intramedullary
• CPC Class Codes: A61B 17/1668 for the upper femur A61B17/164 takes precedence
• CPC Class Codes: A61B 17/1675 for the knee
• CPC Class Codes: A61B 17/1684 for the shoulder
• CPC Class Codes: A61B 2090/061 for measuring dimensions, e.g. length
• CPC Class Codes: A61B 90/06 Measuring instruments not otherwise provided for

Abstract

Methods and systems for installing an implant in an intramedullary canal are discussed. In an example, an intramedullary sounder tool has a sounder head including a plurality of teeth extending proximally from a distal tip towards a shank extending from the sounder head, each tooth comprising a distal cutting edge, a middle scraping edge, and a proximal cutting edge. The sounder head can be advanced into the intramedullary canal until the scraping edge engages cortical bone. If the scraping edge does not engage cortical bone, sounder tools having successively larger diameters can be advanced into the intramedullary canal until a scraping edge does engage the cortical wall, thereby avoiding cutting and damaging of the cortical bone. At such point, the width of the intramedullary canal and the implant used therein can be determined using markings on the shank that indicate the diameter of the sounder head.

Claims

1. A tool for performing an arthroplasty, the tool comprising:

a shank extending along a central axis of the tool; and

a sounder head comprising;

a distal tip;

a plurality of teeth extending proximally from the distal tip towards the shank, each tooth comprising;

a distal cutting edge;

a middle scraping edge; and

a proximal cutting edge; and

a proximal portion connected to the shank.

2. The tool of claim 1, wherein the shank includes graduation marks indicating sizes of the middle scraping edge.

3. The tool of claim 1, wherein each of the distal cutting edges has a first positive rake angle, each of the middle scraping edges has a negative rake angle, and each of the proximal cutting edges has a second positive rake angle.

4. The tool of claim 3, wherein the second positive rake angle is greater than the first positive rake angle.

5. The tool of claim 3, wherein each of the plurality of teeth includes:

a radial tooth surface having;

a distal panel disposed at the first positive rake angle;

an intermediate panel disposed at the negative rake angle; and

a proximal panel disposed at the second positive rake angle.

6. The tool of claim 5 wherein each of the plurality of teeth includes:

an outer tooth surface having;

an arcuate distal segment;

a tapered flat segment extending proximally from the arcuate distal segment; and

a cylindrical flat segment extending proximally from the tapered flat segment.

7. The tool of claim 6 wherein:

the distal panel meets the arcuate distal segment to form the distal cutting edge;

the intermediate panel meets the tapered flat segment to form the scraping edge; and

the proximal panel meets the tapered flat segment to form the proximal cutting edge.

8. The tool of claim 1, wherein the sounder head includes a taper from the proximal cutting edge to the distal cutting edge.

9. The tool of claim 8, wherein the scraping edge includes the taper.

10. The tool of claim 8, wherein the taper is approximately 1.25 degrees relative to the central axis.

11. The tool of claim 1, wherein the proximal cutting edge has a larger diameter than the scraping edge and the distal cutting edge.

12. The tool of claim 1, wherein the sounder head further comprises a cylindrical section extending between the proximal portion and the proximal cutting edges.

13. A method for sizing an intramedullary canal of a bone, the method comprising:

advancing a first sounder tool having a first tapered diameter into a medullary cavity in the bone using a first distal cutting edge of a sounder head; and

stopping advancement of the sounder tool if a first scraping edge of the sounder head engages cortical bone of the bone.

14. The method of claim 13, further comprising:

advancing successive sounder tools having successively larger tapered diameters into the medullary cavity using successively larger distal cutting edges until a successive scraping edge engages cortical bone of the bone.

15. The method of claim 14, further comprising:

taking a diameter measurement of the intramedullary canal using a marking on a shank extending from the sounder head.

16. The method of claim 14, further comprising:

selecting a prosthetic implant having a size based on a diameter of the sounder head that scrapes cortical bone.

17. The method of claim 14, wherein each of the sounder tools has a taper angle that is the same.

18. A tool set for performing an arthroplasty, the tool set comprising:

a first tool comprising;

a first shank; and

a first cutting head, the first cutting head comprising;

a first distal tip;

a plurality of edges extending proximally from the first distal tip towards the first shank, each edge comprising;

a first distal cutting edge;

a first middle scraping edge; and

a first proximal cutting edge; and

a second tool comprising;

a second shank; and

a second cutting head, the second cutting head comprising;

a second distal tip;

a plurality of edges extending proximally from the second distal tip towards the second shank, each cutting edge comprising;

a second distal cutting edge;

a second middle scraping edge; and

a second proximal cutting edge;

wherein a first diameter of the first cutting head is greater than a second diameter of the second cutting head.

19. The tool set of claim 18, wherein the first shank includes a graduation mark indicating the first diameter at a location on the first shank, and the second shank includes a graduation mark indication the second diameter at a location on the second shank.

20. The tool set of claim 18, further comprising:

a first implant having a diameter of the first cutting head; and

a second implant having a diameter of the second cutting head.