Medacta GMK Sphere - Femoral Upsizing;Downsing

GMK Sphere Calipered Kinematic Alignment Surgical Technique
34
Once the position of the sizer is satisfactory, drill the built-in
pins holes through the dedicated holes of the femoral sizer
(blue circles).
CAUTION
While drilling, ensure that contact between the femoral
sizer and the distal resection is maintained.
Finally, remove the femoral sizer and position the 4in1
cutting block of the correct size on the distal resection.
77.
CAUTION
The position of the 4in1 built-in pins DOES NOT
CORRESPOND to the position of the lugs of the femoral
component. The holes for the final femoral component
lugs are created through the trial femoral component.
If one or both distal condyles were over-resected, correct
the position of the 4in1 block using the dedicated 1 and 2
mm washers.
78.
To apply the washer, slide it over the posterior peg of the
4in1 block until it contacts the flat surface of the back of
the 4in1 block. Confirm the washer lies flush.
79.
Check the anterior and posterior resection level using the
angel wing. Whether a femoral upsizing/downsizing or a
4in1 block repositioning is required, see the paragraph
below.
15.3 FEMORAL UPSIZING/DOWNSIZING
The difference between successive femoral sizes is 2 mm
in both anterior-posterior and mediolateral planes.
Posterior Referencing: upsizing/downsizing
Replace the cutting guide with the more suitable size. With
posterior referenced guides, the level of the anterior
resection will change. On the contrary, the posterior
resection will be fixed.
CAUTION
In the event of downsizing, the anterior resection level will
move 2 mm posteriorly. Make sure that there is no anterior
notching.
If it is necessary to move the guide of the chosen size in the
anterior-posterior direction, use the repositioning plate (ref.
02.07.10.3965) for a 2 mm displacement of the guide.
CAUTION
The upward/downward movement of the 4in1 cutting
block will affect the flexion gap.
Remove the 4in1 cutting guide and place the repositioning
plate on the distal resection using the same pin holes. For
the upward/downward movement of the cutting block,
place the repositioning plate as shown in the picture below: