Orthopaedic cutting tool having a chemically etched metal insert and method of manufacturing

Abstract

An orthopaedic surgical instrument comprising an orthopaedic cutting tool includes a metallic cutting insert configured to remove portions of a patient's bone and a body molded to the cutting insert. The cutting insert includes a plurality of chemically etched holes, and the body is molded to the cutting insert such that each of the plurality of chemically etched holes is at least partially filled by a portion of the body. The cutting insert may include a plurality of cutting teeth configured to remove portions of the patient's bone. A method of manufacturing an orthopaedic surgical instrument is also disclosed.

1 . An orthopaedic cutting tool, comprising:
 a metallic cutting insert having a plurality of chemically etched holes, the cutting insert being configured to remove portions of a patient's bone; and   a body molded to the cutting insert such that each of the plurality of chemically etched holes is at least partially filled by a portion of the body.   
     
     
         2 . The orthopaedic cutting tool of  claim 1 , wherein:
 the cutting insert has (i) an interface surface which contacts the body, and (ii) a work surface opposite the interface surface, the work surface configured to remove portions of the patient's bone; and   each of the plurality of chemically etched holes extends from the interface surface to the work surface of the cutting insert.   
     
     
         3 . The orthopaedic cutting tool of  claim 2 , wherein the portion of the body which at least partially fills each chemically etched hole fills at least half the volume of the hole. 
     
     
         4 . The orthopaedic cutting tool of  claim 1 , wherein the cutting insert has (i) a plurality of cutting teeth configured to remove portions of the patient's bone, (ii) at least one relief surface between the plurality of cutting teeth, and (iii) an interface surface opposite the plurality of cutting teeth and the at least one relief surface, the interface surface contacting the body. 
     
     
         5 . The orthopaedic cutting tool of  claim 4 , wherein each of the plurality of chemically etched holes extends from the interface surface to the at least one relief surface of the cutting insert. 
     
     
         6 . The orthopaedic cutting tool of  claim 5 , wherein the portion of the body which at least partially fills each chemically etched hole fills at least half the volume of the hole. 
     
     
         7 . The orthopaedic cutting tool of  claim 1 , wherein the body includes an integrally formed coupling feature. 
     
     
         8 . The orthopaedic cutting tool of  claim 1 , wherein in the body includes an integrally formed handle portion. 
     
     
         9 . The orthopaedic cutting tool of  claim 1 , wherein the body comprises an injection-molded polymer. 
     
     
         10 . An orthopaedic surgical instrument, comprising:
 an orthopaedic cutting tool having (i) a plurality of metallic cutting inserts, each cutting insert having a plurality of chemically etched holes and being configured to remove portions of a patient's bone, and (ii) a body molded to the plurality of cutting inserts such that each of the plurality of chemically etched holes is at least partially filled by a portion of the body.   
     
     
         11 . The orthopaedic surgical instrument of  claim 10 , wherein:
 each of the plurality of cutting inserts has (i) an interface surface which contacts the body, and (ii) a work surface opposite the interface surface, the work surface configured to remove portions of the patient's bone; and   each of the plurality of chemically etched holes extends from the interface surface to the work surface of the respective cutting insert.   
     
     
         12 . The orthopaedic surgical instrument of  claim 10 , wherein:
 the body includes a plurality of cutting flutes, the plurality of cutting flutes arranged radially outward around a longitudinal axis of the orthopaedic cutting tool; and   each of the plurality of cutting inserts is disposed on one of the plurality of cutting flutes.   
     
     
         13 . The orthopaedic surgical instrument of  claim 12 , wherein each of the plurality of cutting inserts is aligned with a leading edge of one of the plurality of cutting flutes to allow a surgeon to remove portions of the patient's bone by rotating the orthopaedic cutting tool about the longitudinal axis. 
     
     
         14 . A method for manufacturing an orthopaedic surgical instrument, the method comprising:
 chemically etching a plurality of holes into a metallic cutting insert; and   molding a body to the cutting insert to form an orthopaedic cutting tool.   
     
     
         15 . The method for manufacturing an orthopaedic surgical instrument of  claim 14 , wherein chemically etching the plurality of holes into the cutting insert comprises chemically etching each of the plurality of holes through the entire thickness of the cutting insert. 
     
     
         16 . The method for manufacturing an orthopaedic surgical instrument of  claim 14 , wherein chemically etching the plurality of holes into the cutting insert comprises:
 forming a mask on the cutting insert, the mask defining a plurality of exposed areas;   placing the cutting insert having the mask in a chemical bath whereby the plurality of exposed areas are chemically etched into the plurality of holes;   removing the cutting insert having the mask from the chemical bath; and   removing the mask from the cutting insert.   
     
     
         17 . The method for manufacturing an orthopaedic surgical instrument of  claim 16 , wherein forming the mask on the cutting insert comprises:
 applying a photoresist material to the cutting insert;   selectively exposing portions of the photoresist material to a light source using a patterned photomask; and   selectively removing portions of the photoresist material using a developer to define the plurality of exposed areas on the cutting insert.   
     
     
         18 . The method for manufacturing an orthopaedic surgical instrument of  claim 14 , wherein molding the body to the cutting insert comprises:
 loading the cutting insert into a mold, the cutting insert contacting a wall of the mold; and   injecting a polymer into the mold such that the cutting insert is pressed against the wall of the mold by the polymer and the polymer at least partially fills the plurality of holes.   
     
     
         19 . The method for manufacturing an orthopaedic surgical instrument of  claim 14 , further comprising chemically etching a plurality of cutting teeth into the cutting insert. 
     
     
         20 . The method for manufacturing an orthopaedic surgical instrument of  claim 19 , wherein the plurality of holes and the plurality of cutting teeth are chemically etched simultaneously.