Preoperative femoral implant sizing

A computing system for femoral implant sizing in advance of a surgical procedure on a patient's knee, the computing system comprising:

• at least one processor;
• and
• at least one memory comprising a plurality of instructions stored thereon that, in response to execution by the at least one processor, causes the computing system to:
• preoperatively acquire at least one image of a distal femur of the patient;
• generate a femoral bone model from the at least one image;
• locate a distal medial condyle, a distal lateral condyle, a posterior medial condyle, and a posterior lateral condyle of the femoral bone model;
• determine a posterior resection plane based on a location of the distal medial condyle, a location of the distal lateral condyle, one or more dimensions of a prospective femoral implant of a selected size, and one or more surgical preferences;
• determine a first distance between the posterior medial condyle and the posterior resection plane and a second distance between the posterior lateral condyle and the posterior resection plane;
• determine a difference between a target value and an average of the first distance and the second distance, wherein the target value is associated with a thickness of the prospective femoral implant;
• and
• select a desired femoral implant size of a plurality of possible femoral implant sizes, in advance of the surgical procedure on the patient's knee, based on the determined difference between the target value and the average of the first distance and the second distance determined for each of the plurality of possible femoral implant sizes.

One or more non-transitory machine-readable storage media for femoral implant sizing in advance of a surgical procedure on a patient's knee comprising a plurality of instructions stored thereon that, in response to execution by a computing device, causes the computing device to:

• preoperatively acquire at least one image of a distal femur of the patient;
• generate a femoral bone model from the at least one image;
• locate a distal medial condyle, a distal lateral condyle, a posterior medial condyle, and a posterior lateral condyle of the femoral bone model;
• determine a primary plane that includes the distal medial condyle and the distal lateral condyle;
• determine an offset of a cortex plane relative to the primary plane based on the selected size and one or more surgical preferences;
• identify a boundary curve indicative of an intersection of the cortex plane and the femoral bone model;
• locate an apex point of the boundary curve, wherein the apex point is an anterior point of the boundary curve;
• determine an apex plane that includes the apex point and is perpendicular to an anterior-posterior direction;
• determine a posterior resection plane based on the apex plane and one or more dimensions of the prospective femoral implant of the selected size;
• determine a first distance between the posterior medial condyle and the posterior resection plane and a second distance between the posterior lateral condyle and the posterior resection plane;
• determine a difference between a target value and an average of the first distance and the second distance, wherein the target value is associated with a thickness of the prospective femoral implant;
• and
• select a desired femoral implant size of the plurality of possible femoral implant sizes in advance of the surgical procedure on the patient's knee, based on the determined difference between the target value and the average of the first distance and the second distance determined for each of the plurality of possible femoral implant sizes and each of the plurality of permitted flexion angles.