Design

Design Considerations

Process Flow

Method for Data Collection

Step 1: STL Import

  • CT data imported into Pro-E as an STL File
  • Units set (mm), Views oriented (ML,AP)






    • Step 2: Resection/Stem Axis

  • Resection plane created
  • Maximum head diameter determined
  • Stem axis planes created based on head diameter






    • Step 3: Canal Center Location

  • Cross sections of bone taken at each plane defined in step II
  • Center of cross section found using triangulation






    • Step 4: Stem Axis Definition

  • Stem axis fit to centers at each cross section
  • Placement optimized using Pro-Engineer behavioral modeling capabilities





    • Step 5: Data Acquisition

  • Starting plane offset from resection center based on head diameter
  • Data points collected at 10 degree intervals as acquisition plane moves down the humerus in 5mm increments




    • Step 6: Data Export

  • Data points collected using Pro-Engineer family table application
  • Data exported to Microsoft Excel for analysis






    • Findings

    Data is ordered by increasing size of the longest diameter at 1.25 x the head height distally from the resection center. Conditional formatting in Excel helps verify that the head height parameter is valid for ordering the sizes- note the small numbers in green and larger in red.

    Patterns noted in geometry along length of canal.

    The shape of the canal contours was used as the basis for stem design. The stem lengths are based on the end of the curvature and beginning of the straight taper shape.