Techniques and instruments for placement of orthopedic implants relative to bone features

Abstract

Methods and instruments for placement of orthopedic implants in bones of a patient. The placement may include selective placement of the implant relative to structure of the bone using a measurement system that may detect interfaces between layers of the bone. The orthopedic implants may be engaged by various embodiments of chucks. The chucks may include structure for engaging indexing features of a corresponding orthopedic implant to restrict movement of the implant relative to the chuck along a working axis. The chucks may allow for use of an instrument having a measurement system for accurate and repeatable placement of the implants using the instrument.

1 .- 43 . (canceled) 
     
     
         44 . A method of advancing an orthopedic implant into a bone of a patient, comprising:
 engaging the orthopedic implant with a chuck of an instrument to restrict axial movement of the orthopedic implant relative to the chuck along a working axis of the chuck;   first advancing the orthopedic implant distally into the bone of the patient a first distance by imparting rotational motion to the chuck when engaged with the orthopedic implant;   first measuring the first distance using a displacement sensor of a measurement system associated with the instrument;   releasing the orthopedic implant from the chuck;   retracting the instrument relative to the orthopedic implant in a proximal direction opposite of the direction of the advancing;   reengaging the orthopedic implant with the chuck of the instrument to restrict axial movement of the orthopedic implant relative to the chuck along a working axis of the chuck; and   second advancing the orthopedic implant distally into the bone of the patient a second distance by imparting rotational motion to the chuck; and   second measuring the second distance using the displacement sensor of the measurement system associated with the instrument.   
     
     
         45 . The method of  claim 44 , further comprising:
 summing the first distance and the second distance at the measurement system.   
     
     
         46 . The method of  claim 45 , further comprising:
 determining that the orthopedic implant is released from the chuck; and   disregarding any change in displacement of the displacement sensor when the orthopedic implant is released from the chuck.   
     
     
         47 . The method of  claim 46 , wherein a sensor is provided relative to the chuck to determine the orthopedic implant is released from the chuck. 
     
     
         48 . The method of  claim 46 , wherein the determining is based on a user input provided to the measurement system. 
     
     
         49 . The method of  claim 44 , wherein the engaging comprises the chuck engaging the orthopedic implant at a first indexing feature of a plurality of indexing features and the reengaging comprises the chuck engaging the orthopedic implant at a second indexing feature of the plurality of indexing features that is proximal to the first indexing feature. 
     
     
         50 . The method of  claim 49 , wherein the engaging occurs in response to the first advancing, the reengaging occurs in response to the second advancing, and the releasing occurs in response to the retracting. 
     
     
         51 . A method of placement of an orthopedic implant relative to a bone of a patient, comprising:
 engaging the orthopedic implant with a chuck of an instrument to restrict axial movement of the orthopedic implant relative to the chuck along a working axis of the chuck;   advancing the orthopedic implant distally into the bone of the patient while the orthopedic implant is engaged with the chuck by imparting rotational motion to the chuck with a drive engaged with the chuck;   measuring at least one characteristic of the advancement of the orthopedic implant relative to the bone;   continuously monitoring the at least one characteristic during the advancing to determine a predetermined placement of a distal end of the orthopedic implant; and   deactivating the drive to cease rotation of the chuck to stop the advancement of the orthopedic implant when the distal end of the orthopedic implant reaches the predetermined placement as determined by the continually monitored at least one characteristic;   wherein the predetermined placement is selectable by a user from a bicortical mode, a subchondral mode, an endosteal mode, and a multi-cortical mode.   
     
     
         52 . The method of  claim 51 , wherein the at least one characteristic comprises a force acting axially on the orthopedic implant and a depth of penetration of the orthopedic implant. 
     
     
         53 . The method of  claim 51 , wherein the at least one characteristic comprises a depth of penetration of the orthopedic implant as determined by a displacement sensor that generates a displacement signal. 
     
     
         54 . The method of  claim 53 , wherein the displacement signal is used to generate a velocity signal and an acceleration signal, wherein the predetermined placement is determined based on the displacement signal, the velocity signal, and the acceleration signal. 
     
     
         55 . The method of  claim 54 , wherein the displacement signal is used to generate a derivative signal comprising a derivative of an acceleration signal generated using the displacement signal, wherein the derivative signal is used to determine the predetermined placement. 
     
     
         56 .- 61 . (canceled)