Tibial insert with resistance-actuated post

Abstract

Trial joint inserts may have posts that slide along a base, compressing or extending a resistance member, such as a spring, as the post slides. During joint replacement surgery, a surgeon can test resistance members with different amounts of resistance using a trial insert, identify a suitable resistance for the resistance member, and then select a permanent insert with a resistance member having the desired resistance. The systems, devices, and methods of this application allow a surgeon to provide an individualized joint replacement for a patient.

1 - 43 . (canceled) 
     
     
         44 . A tibial insert comprising:
 a base;   a resistance-actuated posterior stabilizing post coupled to the base and configured to move relative to the base;   a resistance member that interfaces with the post thereby modulating the movement of the post relative to the base; and   an adjustment member that adjusts the resistance of the resistance member.   
     
     
         45 . The insert of  claim 44 , wherein the base comprises a trough and the resistance member is disposed within the trough. 
     
     
         46 . The insert of  claim 44 , wherein the resistance member compresses or extends when the stabilizing post moves relative to the base. 
     
     
         47 . The insert of  claim 45 , wherein the trough has an anterior end and a posterior end, and a first end of the resistance member contacts the anterior end and a second end of the resistance member contacts the post. 
     
     
         48 . An insert for use in an orthopedic implant, the insert comprising:
 a base;   a resistance-actuated stabilizing post coupled to the base and configured to move relative to the base, wherein the stabilizing post minimizes subluxation of the implant; and   a resistance member that interfaces with the post, thereby modulating the movement of the post relative to the base.   
     
     
         49 . The insert of  claim 48 , wherein the orthopedic implant is a hinge (ginglymus) joint. 
     
     
         50 . The insert of  claim 49 , wherein the hinge joint is selected from the group consisting of a knee joint, an elbow joint, an ankle joint, an interphalangeal articulation of the hand, and an interphalangeal articulation of the foot. 
     
     
         51 . The insert of  claim 48 , wherein the insert further comprises an anchoring member that anchors the resistance member to the base. 
     
     
         52 . The insert of  claim 51 , wherein the anchoring member releasably anchors the resistance member to the base. 
     
     
         53 . The insert of  claim 48 , wherein the insert further comprises an adjustment member that adjusts the resistance of the resistance member. 
     
     
         54 . A kit for fitting a tibial insert, the kit comprising:
 a plurality of tibial inserts, each comprising:
 a base; 
 a resistance-actuated posterior stabilizing post coupled to the base and configured to move relative to the base; and 
 a resistance member that interfaces with the post and the base; 
   wherein each respective resistance member in the plurality of inserts has a different amount of resistance.   
     
     
         55 . A kit for fitting a tibial insert, the kit comprising:
 a tibial insert, comprising:
 a base; 
 a resistance-actuated posterior stabilizing post coupled to the base and configured to move relative to the base; and 
 an anchoring member; and 
   a plurality of a resistance members having different amounts of resistance, each resistance member sized to couple to the base and to compress or extend when the posterior stabilizing post slides relative to the base.   
     
     
         56 . The kit of  claim 55 , wherein the anchoring member releasably anchors each resistance member to the base. 
     
     
         57 . The kit of  claim 55 , wherein the resistance member is a spring and the amount of resistance corresponds to the spring constant. 
     
     
         58 . The kit of  claim 55 , wherein the posterior stabilizing post and the resistance member are disposed in a trough within the base. 
     
     
         59 . A method of determining a desired resistance for a resistance member in a tibial insert, comprising:
 (a) placing, in a patient's joint, at least one trial tibial insert comprising a resistance-actuated posterior stabilizing post and a resistance member configured to interface with the post;   (b) flexing the patient's joint at least twice, wherein at each flex a resistance member having a different resistance is caused to interface with the post, so causing the resistance member to compress or extend;   (c) evaluating at least two fits of the trial insert relative to fitting criteria based on the flexing of step (b); and   (d) determining a desired resistance for the resistance member based on the evaluation of the fits.   
     
     
         60 . The method of  claim 59 , wherein step (b) includes sequentially testing at least two resistance members having different amounts of resistance. 
     
     
         61 . The method of  claim 60 , further comprising evaluating a fit of each of the two resistance members. 
     
     
         62 . The method of  claim 59 , wherein step (b) includes sequentially placing in the patient's joint first and second trial tibial inserts, the first trial tibial insert having a first resistance member having a first resistance, and the second trial tibial insert having a second resistance member having a second resistance. 
     
     
         63 . The method of  claim 62 , further comprising evaluating a fit of the first insert having the first resistance member and evaluating a fit of the second insert having the second resistance member. 
     
     
         64 . The method of  claim 59 , wherein step (b) includes altering the resistance of the resistance member by moving an adjustment member. 
     
     
         65 . The method of  claim 64 , wherein moving the adjustment member comprises turning a screw. 
     
     
         66 . The method of  claim 64 , wherein moving the adjustment member comprises altering the position of a plate disposed within a trough disposed within the base of the insert and coupled to the resistance member. Preliminary Amendment