Zimmer MIS Multi-Reference, Хирургическая техника, Страница: 15 / 48

Zimmer MIS Multi-Reference 4-in-1 Femoral Instrumentation Surgical Technique
13
Step Three
Size Femur and Establish
External Rotation
Flex the knee to 90°. Attach the MIS
Threaded Handle to the Mini A/P Sizing
Guide, and place the guide flat onto
the smoothly cut distal femur (Fig. 3a).
Apply the guide so that the flat surface
of the Mini A/P Sizing Guide is flush
against the resected surface of the
distal femur and the feet of the Mini
A/P Sizing Guide are flush against the
posterior condyles.
Slide the body of the Mini A/P Sizing
Guide along the shaft to the level of
the medullary canal. Position the guide
mediolaterally, and check the position
by looking through both windows of
the guide to ensure that the medullary
canal is not visible through either.
NOTE: Remove any osteophytes that
interfere with instrument positioning.
While holding the Mini A/P Sizing
Guide in place, secure the guide to
the resected distal femur using short
3.2mm (1/8 inch) Headed Screws or
predrill and insert short head Holding
Pins into one or both of the holes in
the lower portion of the guide. Do not
overtighten or the anterior portion will
not slide on the distal femur.
MIS Screws are available in 3 lengths
(27mm, 33mm, 48mm). The length
needed will vary depending on the
patient’s bone dimensions.
NOTE: Remove the Threaded
Handle before using the Screw
Inserter/Extractor.
Slightly extend the knee and retract
soft tissues to expose the anterior
femoral cortex. Clear any soft tissue
from the anterior cortex. Ensure that
the leg is in less than 90° of flexion
(70°-80°). This will decrease the
tension of the patellar tendon to
facilitate placement of the guide.
Attach the MIS Locking Boom to the
Mini A/P Sizing Guide. Ensure that the
skin does not put pressure on the top
of the boom and potentially change
its position. The position of the boom
dictates the exit point of the anterior
bone cut and the ultimate position
of the femoral component. When the
boom is appropriately positioned, lock
it by turning the knurled knob (Fig. 3b).
See Appendix 1 for alternative MIS
Telescoping Locking Boom technique.
Fig. 3a
Fig. 3b
Fig. 3c
Read the femoral size directly from
the guide between the engraved lines
on the sizing tower (Fig. 3c). There are
eight sizes labeled “A” through “H”. If
the indicator is between two sizes, the
closest size is typically chosen. If using
a posterior referencing technique, and
the indicator is between two sizes,
the larger size is typically chosen to
help prevent notching of the anterior
femoral cortex.