Technique
UKA
Lee Beom Koo
Gachon university Gil Hospital
Pre-op measurement of
tibia resection line & slope
Lateral joint line을 기준으로 joint에 parallel 하게 선을 긋고
그선에서 7mm하방으로 선을 그은 후 그선 과tibia medial plateau
와의 거리를 측정한 다 ( 대개 2-4 mm이다)
Lateral 사진을 보고sagittal slope측정하여 7 도 이하이면 natural
slope로 ,cutting line을 정하고
7도이상이면 slope를 7도 정도에 맞추어 자른 다
Approach
AM arthrotomy후 proximal tibia의medial
soft tissue 를 elevation하는 데 deep
MCL과 MCL tibia insertion중 proximal
insertion은 elevate 한다
그후 The anterior part of medial
meniscus 을 자르고 The medial spur도
rongeur and osteotome 으로 자른 다
Evaluation of joint
While the patella is retracted.
Resistance of ACL and state
of cartilage of lateral &
patellofemoral joint is
inspected
Exposure of medial compartment
patella를 retraction후
MCL 을 MCL retractor로 retract하고 다
리를 slight external rotation of leg 하면
전체적으로 좋은 시야가 나온 다
Adjustment and fixation of tibia guide
Guide의 shaft를 tibia crest에 맞추어coronal alignment결정후 하나의
screw를 박아서 coronal alignment를 정한다
Guide의 center를 술전 tibia axis맞나는 곳에 둔다
Adjustment and fixation of tibia guide
Sagittal slope 를 재고 distal 에서 guide를 올려서slope 를
정한다
. The natural slope is preferred But slope greater than
7 is not recommended
Horizontal cut
MCL retractor 로 MCL protection요하며.
•
역시 너무 깊이 들어가 N_V 손상주지 않도록 조심 해야한다
The sagittal tibial cut
위치 ;
The sagittal cutting line is marked at the medial edge
of ACL
Rotation;
Sagittal cut line point toward the Femoral head in
flexion
,akaki line
medial femoral condyle wall방향
깊이;
너무 깊지 않게 , 깊으면 후에 tibia fx올수
있다
Balance in extension
After placement of sliding
spacer block, the medial
joint space should open
up 1 or 2 mm when
valgus stress is applied
with the knee in full
extension.
It is very important to
avoid overstuff &
overcorrection
Balance in flexion
,
2 to 3 mm laxity is suggested.in medial
UKA after placing block
For the balance in flexion,
the thigh should be lifted
with one arm to balance
the flexion gap
If the flexion gap is too tight;
first step
종종 pre-op tibia slope가 7도 이상이나
tibia 를 slope를 7도로 주고 하면 flexion
gap이 tight해진 다
If the flexion gap is too tight , cartilage
or bone should be removed from the
posterior condyle of femur with rasp or
saw
or The slope should be slightly
increased
Marking of femoral rotation line
Next step for the Marking of
femoral rotation line
the center of the tibial spacer
block is marked with a Bovie on
the femoral condyle in different
positions
It should not be judged while the
patella is everted
or perpendicular line to the cut tibia bone
can be chosen
Distal femoral cut
the distal femoral
cutting guide is
slided in extension
and fixed with two
pin and resected .
The knee should
be flexed 5 if the
resected posterior
slope of tibia is 5
to avoid
hyperextension.
shim can be used
to manage the
bone defect.
Distal cut가 flex해지면 flex gap이 tight해진다
Distal cut가 flex해지면 flex gap이 tight해진다
Distal femoral cut
Finishing cutting guide placement
.
Femur finishing guide is
inserted in 90 degree
flexion
Finishing cut ;Size
If the size is proper,
1 to 2 mm of exposed bone . At the anterior edge
Mediolateral dimension
For the correct mediolateral position, The guide
should be placed in the center of the femoral
condyle,mediolaterally
Rotation
femoral rotation may follow
the previously Marked
rotation line or
This guide should also be
rotationally set so that the
posterior cutting surface of
femoral condyle is parallel to
the resected tibia
Fixation of finishing guide
Posterior & Champer cut
Finishing guide is fixed with two screw.
at the Anterior margin of guide, bone is gouged slightly to accept the
curved prosthesis
While the MCL is protected with MCL retractor placed at femoral side, the
posterior femur is resected and after anterior and posterior chamfer cut ,
two femoral peg hole is drilled
1st alignment check
Post. Condyle trimming to
avoid impingement posteriorly
Post. Condyle trimming to avoid
impingement posteriorly
The final preparation of the tibia;
exposure
The leg is externally exposed, while the
MCL is retracted to expose the whole
medial compartment
The size of the tibial tray
Size는 AP 길이를 보고 결정해야한다
종종 ACL 보다 떨어져서 sagittal cut하는데 medial크기가 작아진 다
그후 coronal plane으로 크기 정하면 AP상 적은 크기가 들어가고
cortical support가 안 된다; tibia plate가 cancelleous bone에만 걸
치므로 조기collapse가 온 다
Tibia preparation;
tibia guide 넣고 일시적으로 tensor로 눌러서 고정후 the keel 을
특수한 osteotome을 써서 하며 peg hole
을 drilled
tibia의 posterior margin을 정확히 파악 후 하여야 하며
종종 tibia guide가 뒤로 가는 경우가 많으니 anterior cortical
shell에 guide의 margin을 맞 추는 것 이 좋다
Alignment check
Tibia cement
• Staged cementing
• Avoid tilt of tibia
plate especially
posterior ( which
result in tightness in
flexion.
• adequate exposure
of posteromedial
tibia
• adequate sizing
tilt of tibia plate especially posterior
• Easily happen when simultaneous
cementing because knee extension
cause pressure anteriorly
• which result in tightness in flexion
• Cement defect posteriorly.
Femoral cement
• Cement is applied
wholly to prosthesis
and femoral cut
surface except
posterior condyle &
prosthesis is
inserted & impacted
Argenson, Jean-Noel A MD; Parratte,
corr 464 Nov 2007 P32
Liner insertion
• In flexion ,
the liner is
inserted with
hand
alignment
• The ideal correction as
measured on the
postoperative full
weightbearing view will
probably consist of a
tibiofemoral axis crossing the
knee between the tibial
spines and the medial third of
the tibial plateau for a medial
UKA
Argenson, Jean-Noel A MD;
Parratte,
corr 464 Nov 2007 P32
Kennedy WR, White RP. Unicompartmental
arthroplasty of the knee; post-operative alignment
and its influence on overall results. Clin Orthop Relat
Res. 1987;221:278-285
Lateral Unicompartmental
Replacement
Lateral Unicompartmental Knee Arthroplasty: Survivorship and
Technical Considerations at an Average Follow-Up of 12.4 Years
• unique tibial
component positioning
in 10° to 15° of internal
rotation to compensate
for the “screw-home”
mechanism
• Transpatella tendon
sagittal sawing or
medial approach is
helpful( AAOS 2012)
Pages 13-17 Jan'06 J arthroplasty
Donald W. Pennington, John J.
Swienckowski, William B. Lutes and
Gregory N. Drake
Trans patella
tendon sag
saw in lat
UKA to
achive IR in
tibia resection ,
trans tibial
axis rotation
Femur ; trans
tibia rotation
Keith R. Berend
Clin Orthop Relat Res (2012) 470:77–83
Flexion gap balancing
• Balancing is
similar to that
for a medial
UKA, but
looser; play of
2 to 3 mm
instead of 1 to
2 mm (medial
UKA) is
suggested.
Scott
Insall 4th edit P 1413
Thank you for
your attention