AIM: To introduce the navigation system of software and instruments designed specifically for revision total knee arthroplasty(TKA).METHODS: We present an imageless navigation system for revision TKA,with optical poin...AIM: To introduce the navigation system of software and instruments designed specifically for revision total knee arthroplasty(TKA).METHODS: We present an imageless navigation system for revision TKA,with optical point and tracker identification to assess kinematic and anatomical landmarks.The system automatically positions the cutting guides with a motorized cutting unit.The cutting unit is placed on the distal femur with a femoral clamp and acts as a rigid body and the base for all femoral cuts.The surgical technique for using the navigation system for revision TKA is based on the technique used in primary TKA.However,there are some important differences.The most notable are:(1) differences in estimation of the position of the primary implant relative to the bone and the mechanical axes;(2) the specific possibilities the revision navigation software offers in terms of optimal joint level positioning; and(3) the suggested "best fit" position,in which the clock position,stem position and offset,femoral component size,and mediolateral position of the femoral component are taken into account to find the optimal femoral component position.We assessed the surgical technique,and accompanying software procedural steps,of the system,identifying any advantages or disadvantages that they present.RESULTS: The system aims to visualize critical steps of the procedure and is intended as a tool to support the surgeon in surgical decision-making.Combining a computer-assisted cutting device with navigation makes it possible to carry out precise cuts without pinning.Furthermore,the femoral clamp provides a stable fixation mechanism for the motorized cutting unit.A stable clamp is paramount in the presence of periarticular bony defects.The system allows the position of the primary implant relative to the bone and mechanical axes to be estimated,at which point any malalignments can be corrected.It also offers an optimal joint level position for implantation,and suggests a "best fit" position,in which the clock position,stem position and offset,femoral component size,and mediolateral position of the femoral component are considered.The surgeon can therefore make decisions intraoperatively to maximise alignment and,hence,outcomes.Based on the intraoperative findings of joint stability,the surgeon can modify the preoperative plan and switch from a constrained condylar system to a hinged version,or vice versa.CONCLUSION: The system is flexible and easy to learn and allows improvements in workflow during TKA.展开更多
Serous Purpose: There is limited information in the literature surrounding the use of patient-specific instrumentation (PSI) by a large number of surgeons. This prospective observational study was therefore designed t...Serous Purpose: There is limited information in the literature surrounding the use of patient-specific instrumentation (PSI) by a large number of surgeons. This prospective observational study was therefore designed to evaluate the logistics of using PSI for total knee arthroplasty (TKA) in a multi-surgeon environment, as well as its accuracy in positioning components. Methods: Of 73 patients enrolled in this study, 3 were excluded after the surgeon decided intraoperatively to switch to conventional instrumentation. Results: Mean operative time was 77.6 minutes. The component size had to be changed in 19 patients and bone cuts corrected in 12. In 65 of the 70 cases (92.9%), mechanical alignment was within the optimal range from 3° varus to 3° valgus, with the remaining 5 cases considered outliers (7.1%). Mean overall mechanical alignment was 0.3° varus (standard deviation, ±2°). There was a distinct variance with regard to the position of the tibial component in the sagittal plane. Conclusions: PSI can be effectively incorporated in larger, multisurgeon practices. Although high accuracy was observed for overall mechanical alignment and component positioning in the frontal and sagittal planes, further attention must be paid to the tibial slope. We highly recommend the use of the extramedullary alignment rod to the proper position of the tibial block, as well as double-checking the slope before performing bone cuts.展开更多
基金Supported by Smith and Nephew Gmb H,Marl,Germany
文摘AIM: To introduce the navigation system of software and instruments designed specifically for revision total knee arthroplasty(TKA).METHODS: We present an imageless navigation system for revision TKA,with optical point and tracker identification to assess kinematic and anatomical landmarks.The system automatically positions the cutting guides with a motorized cutting unit.The cutting unit is placed on the distal femur with a femoral clamp and acts as a rigid body and the base for all femoral cuts.The surgical technique for using the navigation system for revision TKA is based on the technique used in primary TKA.However,there are some important differences.The most notable are:(1) differences in estimation of the position of the primary implant relative to the bone and the mechanical axes;(2) the specific possibilities the revision navigation software offers in terms of optimal joint level positioning; and(3) the suggested "best fit" position,in which the clock position,stem position and offset,femoral component size,and mediolateral position of the femoral component are taken into account to find the optimal femoral component position.We assessed the surgical technique,and accompanying software procedural steps,of the system,identifying any advantages or disadvantages that they present.RESULTS: The system aims to visualize critical steps of the procedure and is intended as a tool to support the surgeon in surgical decision-making.Combining a computer-assisted cutting device with navigation makes it possible to carry out precise cuts without pinning.Furthermore,the femoral clamp provides a stable fixation mechanism for the motorized cutting unit.A stable clamp is paramount in the presence of periarticular bony defects.The system allows the position of the primary implant relative to the bone and mechanical axes to be estimated,at which point any malalignments can be corrected.It also offers an optimal joint level position for implantation,and suggests a "best fit" position,in which the clock position,stem position and offset,femoral component size,and mediolateral position of the femoral component are considered.The surgeon can therefore make decisions intraoperatively to maximise alignment and,hence,outcomes.Based on the intraoperative findings of joint stability,the surgeon can modify the preoperative plan and switch from a constrained condylar system to a hinged version,or vice versa.CONCLUSION: The system is flexible and easy to learn and allows improvements in workflow during TKA.
文摘Serous Purpose: There is limited information in the literature surrounding the use of patient-specific instrumentation (PSI) by a large number of surgeons. This prospective observational study was therefore designed to evaluate the logistics of using PSI for total knee arthroplasty (TKA) in a multi-surgeon environment, as well as its accuracy in positioning components. Methods: Of 73 patients enrolled in this study, 3 were excluded after the surgeon decided intraoperatively to switch to conventional instrumentation. Results: Mean operative time was 77.6 minutes. The component size had to be changed in 19 patients and bone cuts corrected in 12. In 65 of the 70 cases (92.9%), mechanical alignment was within the optimal range from 3° varus to 3° valgus, with the remaining 5 cases considered outliers (7.1%). Mean overall mechanical alignment was 0.3° varus (standard deviation, ±2°). There was a distinct variance with regard to the position of the tibial component in the sagittal plane. Conclusions: PSI can be effectively incorporated in larger, multisurgeon practices. Although high accuracy was observed for overall mechanical alignment and component positioning in the frontal and sagittal planes, further attention must be paid to the tibial slope. We highly recommend the use of the extramedullary alignment rod to the proper position of the tibial block, as well as double-checking the slope before performing bone cuts.
