System and method for image segmentation in generating computer models of a joint to undergo arthroplasty

A method of manufacturing a custom arthroplasty guide, the guide including a mating region configured to matingly receive a portion of a patient bone associated with an arthroplasty procedure for which the custom arthroplasty guide is to be employed, the mating region including a surface contour that is generally a negative of a surface contour of the portion of the patient bone, the surface contour of the mating region being configured to mate with the surface contour of the portion of the patient bone in a generally matching or interdigitating manner when the portion of the patient bone is matingly received by the mating region, the method of manufacture comprising:

• a) generating medical imaging data of the portion of the patient bone;
• b) identifying landmarks associated with bone boundaries in the medical imaging data;
• c) providing a geometrical representation of an exemplary bone that is not the patient bone but is the same bone type as the patient bone and is representative of what is considered to be generally normal with respect to the bone type for at least one of size, condition, shape, weight, age, height, race, gender or diagnosed disease condition;
• d) adjusting the geometrical representation of the exemplary bone to match the landmarks;
• e) using the adjusted geometrical representation of the exemplary bone to generate a three dimensional computer model of the portion of the patient bone;
• f) using the three dimensional computer model to generate design data associated with the custom arthroplasty guide;
• and
• g) using the design data in manufacturing the custom arthroplasty guide.

A method of manufacturing a custom arthroplasty guide, the guide including a mating region configured to matingly receive a portion of a patient bone associated with an arthroplasty procedure for which the custom arthroplasty guide is to be employed, the mating region including a surface contour that is generally a negative of a surface contour of the portion of the patient bone, the surface contour of the mating region being configured to mate with the surface contour of the portion of the patient bone in a generally matching or interdigitating manner when the portion of the patient bone is matingly received by the mating region, the method of manufacture comprising:

• a) generating medical imaging slices of the portion of the patient bone;
• b) identifying landmarks on cortical bone boundaries in the medical imaging data;
• c) providing golden bone image data that is not of the patient bone but is of the same bone type as the patient bone and is representative of what is considered to be generally typical with respect to a characteristic of bones such as the patient bone;
• d) segmenting the golden bone image data and generating a golden bone mesh from the segmented golden bone image data;
• e) deforming the golden bone mesh to match the landmarks;
• f) generating at least one of segmentation curves or spline curves from the deformed golden bone mesh;
• g) modify the at least one of segmentation curves or spline curves to match the landmarks;
• h) using the modified at least one of segmentation curves or spline curves to generate a three dimensional computer model generally representative of the portion of the patient bone;
• i) using the three dimensional computer model to generate design data associated with the custom arthroplasty guide;
• and
• j) using the design data in manufacturing the custom arthroplasty guide.