Adjustable femoral resection guide
View Patent ↗A chamfer resection guide assembly for effecting chamfer cuts into a resected distal surface of a femur in connection with a distal total knee implant has an anchor member configured for anterior referencing of the chamfer cuts, a block member including one or more cutting guide slots for guiding a cutting tool for making chamfer resections and a camming member. The camming member operably connects the block member and the anchor member and the position of the block member with respect to the anchor member is adjusted by operation of the camming member thus allowing adjustment of the position of the cutting guide slots with respect to the anchoring member.
1. A chamfer resection guide assembly for effecting chamfer cuts into a resected distal surface of a femur in connection with a distal total knee implant, the chamfer resection guide assembly having an anterior end and comprising:
an anchor member configured for anterior referencing of the chamfer cuts;
a block member including one or more cutting guide slots and a femoral contacting surface for placement against the resected distal surface of the femur, wherein the femoral contacting surface is provided with a recessed region in which the anchor member is slidably engaged therein,
wherein the anchor member comprises a second femoral contacting surface and a footplate extension that extends from the second femoral contacting surface near the anterior end of the chamfer resection guide assembly; and
a camming member operably connecting the block member and the anchor member and configured for linearly displacing the anchor member and the block member with respect to each other by a camming action;
wherein the block member is provided with a blind hole provided in the recessed region and the anchor member is provided with a blind slot, wherein the camming member is captured between the block member and the anchor member by engaging the blind hole and the blind slot, whereby turning the camming member about its longitudinal axis produces the camming action;
wherein the camming member comprises:
a first end engaging the blind hole of the block member;
a second end engaging the blind slot of the anchor member; and
an elastically compressible member contained between the first end and the second end and urging the first end against the block member and the second end against the anchor member.
2. The chamfer resection guide assembly of claim 1 , wherein the first end is configured to engage the blind hole in a locking manner preventing the camming member from being rotated about its longitudinal axis when the first end is urged against the block member.
3. The chamfer resection guide assembly of claim 2 , wherein the first end and the second end are coupled together by a mortise and tenon joint.
4. The chamfer resection guide assembly of claim 2 , wherein the second end comprises:
a cam body having a center aligned with the camming member's longitudinal axis; and
an offset cylinder boss whose center is offset from the center of the cam body, wherein the offset cylinder boss engages the blind slot, wherein when the camming member rotates about its longitudinal axis, the offset cylinder boss produces the camming action.
5. The chamfer resection guide assembly of claim 1 , wherein the first end is configured to disengage the blind hole and be rotatable about its longitudinal axis when the first end is pushed inward, compressing the elastically compressible member.
6. The chamfer resection guide assembly of claim 5 , wherein the block member has a top side and a second femoral contacting side, the blind hole being provided with a retaining lip at the top side of the block member wherein the retaining lip forms a non-circular terminal opening for the blind hole at the top side for engaging the first end of the camming member in a locking manner.
7. The chamfer resection guide assembly of claim 6 , wherein the first end and the second end are coupled together by a mortise and tenon joint.
8. The chamfer resection guide assembly of claim 6 , wherein the second end comprises:
a cam body having a center aligned with the camming member's longitudinal axis; and
an offset cylinder boss whose center is offset from the center of the cam body, wherein the offset cylinder boss engages the blind slot, wherein when the camming member rotates about its longitudinal axis, the offset cylinder boss produces the camming action.
9. The chamfer resection guide assembly of claim 1 , wherein the first end and the second end are configured to translate axially with respect to each other while rotating about the camming member's longitudinal axis in unison.
10. The chamfer resection guide assembly of claim 9 , wherein the first end and the second end are coupled together by a mortise and tenon joint.
11. The chamfer resection guide assembly of claim 9 , wherein the second end comprises:
a cam body having a center aligned with the camming member's longitudinal axis; and
an offset cylinder boss whose center is offset from the center of the cam body, wherein the offset cylinder boss engages the blind slot, wherein when the camming member rotates about its longitudinal axis, the offset cylinder boss produces the camming action.
12. The chamfer resection guide assembly of claim 1 , wherein the first end of the camming member is configured to receive a tool for turning the camming member.