Systems and methods for joint balancing
Disclosed herein is a balancer algorithm to perform joint balancing calculations to identify target solutions based on surgeon preference. The balancer algorithm can generate a suggested final implant plan from a predetermined range. The balancer algorithm can be used in a knee arthroplasty procedure to generate bone resection depths, bone gaps, implant angulations, required soft tissue release, etc. Input to the balancer algorithm can include preoperative data, intraoperative data, and surgeon preference data.
1 . A method of determining femoral and tibial implant angulations for a knee arthroplasty procedure, the method comprising the steps of:
inputting preoperative knee data to an input screen of a computing device, the preoperative knee data including initial femoral and tibial resection depths;
selecting targeted postoperative knee data using the input screen, the targeted postoperative knee data including targeted implant angulations and implant angulation ranges, the targeted implant angulations including the femoral implant angulation with reference to a femur, and the tibial implant angulation with reference to a tibia;
determining a plurality of planned implant angulations using a balancer algorithm of the computing device based on preoperative knee data and intraoperative knee data, the plurality of planned implant angulations being within the implant angulation ranges,
scoring the plurality of planned implant angulations using the balancer algorithm based on a weighted combination of medial epicondylar drift, lateral column length, proximity to target angulations and gap deviations from ideal gaps;
ranking the plurality of planned implant angulations based on the scoring to select final implant angulations; and
displaying final implant angulations from the plurality of planned implant angulations on an output screen of the computing device, wherein the final implant angulations are within the targeted postoperative implant angulation ranges.
2 . The method of claim 1 , wherein the step of selecting the final implant angulations is performed in real time in response to any change of the targeted postoperative knee data.
3 . The method of claim 2 , wherein the final implant angulations include a final femoral implant angulation, a final femoral implant rotation, and a final tibial implant angulation.
4 . The method of claim 2 , wherein the preoperative knee data includes initial femoral and tibial resection depths.
5 . The method of claim 4 , wherein the initial femoral and tibial resection depths include an initial distal medial femoral resection depth, an initial distal lateral femoral resection depth, an initial posterior medial femoral resection depth, and an initial posterior lateral femoral resection depth.
6 . The method of claim 5 , wherein the initial femoral tibial resection depths include an initial medial tibial resection depth and an initial proximal lateral tibial resection depth.
7 . The method of claim 5 , wherein the preoperative knee data includes initial femoral implant angulation and rotation.
8 . The method of claim 7 , wherein the preoperative knee data includes an initial tibial implant angulation.
9 . The method of claim 8 , wherein the preoperative knee data includes initial medial and lateral extension and flexion gaps.
10 . The method of claim 9 , wherein the preoperative knee data includes initial limb extension and flexion angles.
11 . The method of claim 5 , wherein the targeted postoperative knee data includes a targeted postoperative femoral implant angulation range and a targeted postoperative femoral implant rotation range.
12 . The method of claim 11 , wherein the targeted postoperative knee data includes a targeted postoperative tibial implant angulation range.
13 . The method of claim 12 , wherein the targeted postoperative knee data includes targeted postoperative medial and lateral extension gap ranges.
14 . The method of claim 13 , wherein the targeted postoperative knee data includes targeted postoperative limb extension and flexion angle ranges.
15 . The method of claim 12 , wherein the step of determining the plurality of planned implant angulations includes the steps of:
iteratively calculating gaps falling between targeted postoperative gap ranges;
iteratively calculating tibial implant angulations falling between the targeted postoperative tibial angulation range;
iteratively calculating femoral resections depths falling between the initial femoral resection depths, and
iteratively calculating a required soft tissue release and a required quadrant for the release.
16 . The method of claim 15 , wherein the medial epicondylar drift is calculated from a femoral component shift.
17 . The method of claim 16 , wherein the targeted postoperative knee data includes the required soft tissue release in a medial extension quadrant, a lateral extension quadrant, a medial flexion quadrant or a lateral flexion quadrant.
18 . The method of claim 1 , wherein the balancer algorithm generates the plurality of planned implant angulations for a single patient intra-operatively during the knee arthroplasty procedure.
19 . The method of claim 1 , wherein the plurality of planned implant angulations comprises a list of solutions, wherein the balancer algorithm displays the plurality of planned implant angulations on the output screen in order of their respective scores from lowest to highest.