14 |
NexGen MIS LPS-Flex Mobile Implant System
Surgical Technique
Valgus Release
When correcting a fixed valgus deformity, the lateral
release will include the arcuate complex, iliotibial
band and lateral collateral ligament. When possible
the popliteus tendon is preserved to maintain flexion
stability.
In contrast to that of a varus release, the principle of
a valgus release is to elongate the contracted lateral
structures to the length of the medial structures.
Though lateral osteophytes may be present and
should be removed, they do not bowstring the lateral
collateral ligament in the same way as osteophytes on
the medial side.
This is because the distal insertion of the lateral
collateral ligament into the fibular head brings the
ligament away from the tibial rim.
For a valgus release, a “piecrust” technique may be
preferable. This technique allows lengthening of the
lateral side while preserving a continuous soft tissue
sleeve, as well as preserving the popliteus tendon,
which ensures stability in flexion.
With the knee in extension and distracted with a
laminar spreader, use a 15 blade to transversely cut
the arcuate ligament at the joint line.
Be careful not
to cut or detach the popliteus tendon.
Then use the
15 blade to pierce the iliotibial band and the lateral
retinaculum in a “piecrust” fashion, both proximally
above the joint and distally within the joint. Following
the multiple punctures, use a laminar spreader to
stretch the lateral side. This should elongate the lateral
side and create a rectangular extension space. Use
spacer blocks to confirm ligament balance in flexion
and extension
For a severe fixed valgus deformity it may be necessary
to perform a complete release of the lateral supporting
structures including the lateral collateral ligament,
lateral capsule, arcuate complex, and popliteus
tendon. This can be performed by sharply detaching
the popliteus tendon, lateral collateral ligament
and posterolateral capsule from the lateral femoral
epicondyle. This release can then be extended around
the posterolateral corner of the femur, detaching
the capsular attachments. The release is extended
proximally and will detach the lateral supporting
structures, including the intermuscular septum to a
point 7-8 cm from the joint line so that the whole
lateral flap is free to slide and is effectively lengthened.
Another method is to osteotomize the lateral femoral
epicondyle. The bone shingle created has the
aforementioned soft tissue structures attached and
affords the appropriate release. Occasionally, the
lateral head of the gastrocnemius requires division.
Rarely is division of the biceps femoris required.
Following bone resection and soft tissue release, the
flexion and extension gaps are measured and should
be equal and symmetrical.
Any differences must be addressed.
Contracture
Tensed
Lax
M
L
L
M
Figure 11
Содержание NexGen MIS LPS-Flex
Страница 1: ...NexGen MIS LPS Flex Mobile Implant System Surgical Technique ...
Страница 69: ......
Страница 70: ...68 NexGen MIS LPS Flex Mobile Implant System Surgical Technique Notes ...
Страница 71: ......