GMK Sphere Calipered Kinematic Alignment Surgical Technique
16
5.8 TIBIAL RESECTION
Bring the tibial cutting guide into contact with the tibia by
sliding it along the pins. If an increase in stability is required,
a third oblique pin can be introduced through the oblique
hole of the tibial slotted cutting block.
31.
CAUTION
Check that the rotation and varus/valgus of the tibial
cutting guide has not changed during disassembly of the
guides before performing the resection.
Finally, perform the tibial proximal resection by cutting with
a 1.27 mm thickness saw blade through the slot built into
the guide. Slide the tibial cutting block over its two parallel
pins and remove it.
VERIFICATION CHECK
Measure the thickness of the resected medial and lateral
tibial condyles at the base of the tibial spines. This two
measurements should be equal ± 0.5 mm. When one tibial
condyle is thinner than the other by 1 mm or more, expect
tightness in that compartment and/or slackness in the
other when assessing varus-valgus laxity with the knee in
full extension. Confirm the slope of the medial tibial
resection is parallel to the native slope after compensating
for wear. Any adjustment is performed only after checking
the flexion/extension gap, as described in the following
sections.
32.
6. FLEXION GAP CHECK
Test the flexion gap using the flexion-extension spacers
(available thicknesses: 10, 11, 12, 13, 14 mm). Use the side
marked as “FLEX”.
At 90° of flexion lateral laxity should be higher than medial
laxity, which matches the native laxities of the knee.
33.
VERIFICATION CHECK
Assess the relative tightness between the medial and
lateral compartments by internally and externally rotating
the spacer. The spacer should fit tight and pivot about the
medial compartment and fit loose in the lateral
compartment. This tighter medial/looser lateral fit indicates
a trapezoid shaped flexion space like the native knee.
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