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Persona The Personalized Knee
Surgical Technique
Persona Anterior Referencing Sizer
42-5099-088-10
2.5 mm Male Hex Driver
42-5099-025-00
25 mm x 2.5 mm Female Hex Screw
42-5099-025-25
Size Femur and
Establish External Rotation
Rotate the feet of the anterior referencing femoral
sizing guide so the appropriate “Left” or “Right”
markings are visible as the femoral sizing guide is
placed on the bone (Figure 36). External rotation can
be set at 3 degrees or 5 degrees from the posterior
condylar axis.
Technique Tip:
Remove any osteophytes that
interfere with instrument positioning.
Apply the sizer so that the flat surface of the sizer is
flush against the resected surface of the distal femur
and the feet of the sizer are flush against the posterior
condyles. Center the sizer mediolaterally. Both the
vertical and horizontal portions of the sizer provide
visual cues relative to the A/P and epicondylar axes of
the femur to help ensure that desired external rotation
is attained.
Note:
Sizer geometry is rotated 3 degrees to align
to the A/P and epicondylar axes of the femur. The
3 degrees drill holes are rotated 3 degrees from
the posterior feet and are neutral to the central
sizer geometry. This enables use of the A/P and
epicondylar axis to set rotation.
Side
Designation
Figure 36
Figure 37
Figure 38
If the 3 degrees external rotation holes are to be used
to set external rotation, the etched line on the sizer
should be positioned so it is in line with Whiteside’s line
(Figure 37) to optimize the M/L position of the drill
holes for subsequent 4-in-1 cut guide placement. If
the 5 degrees external rotation holes are to be used,
the sizer can be positioned with the etched line on
the sizer 4 mm laterally from Whiteside’s line to better
center the drill holes for subsequent 4-in-1 cut guide
placement, due to the M/L offset of the holes. Hold
the guide in place and if necessary, secure the sizer
to the femur using 25 mm x 3.2 mm (2.5 mm female
hex) screws (Figure 38) in one or both of the holes
on the lower portion of the guide to help draw the
sizer adjacent to the distal femur, particularly in MIS
situations.
Note:
Do NOT use 48 mm screws for fixation of
the anterior reference sizer. 48 mm screws are not
recommended due to potential bone perforation.
Technique Tip:
Do not impact the sizer onto the
femur.