1. Lee Beom Koo Gachon university Gil Hospital
Technique UKA
Lee Beom Koo
Gachon university Gil Hospital

2. tibia resection line & slope
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 plateau와의 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

3. horizontal Tibial resection;depth
the depth of the tibial cut as conservative as possible to take advantage of the strength of the tibial cortex and the increased area of contact proximally
2 to 4 mm off the deepest portion of the medial tibial plateau.
, mm; oxford .
Scott
Insall 4th edit
Argenson, Jean-Noel A MD; Parratte,
corr 464 Nov 2007 P32

4. Important techn in UKA
Our results seem to reflect those seen in registries confirming an earlier higher revision rate and highlight the technical issues of overstuffing the compartment,
The main issues in technique were overstuffing the medial compartment usually as a result of under resection of tibial bone and/or MCL attenuation
The desire for maximal bone preservation cannot supercede the need for adequte bone resection and varus resection on the tibial side aggravated this situation and must be avoided
Initial Experience With the Oxford Unicompartmental Knee Arthroplasty
Geoffrey F. Dervin MD, FRCSC, a, Chris Carruthers MD, FRCSCa, Robert J. Feibel MD, FRCSCa, Alan A. Giachino MD, FRCSCa, Paul R. Kim MD, FRCSCa and Peter R. Thurston MD, FR JA February 2011, Pages

5. 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
MCL retractor 가 쉽게 들어갈 정도
Medial release+meniscus resection

6. Evaluation of joint
While the patella is retracted. Resistance of ACL and state of cartilage of lateral & patellofemoral joint is inspected .

7. Exposure of medial compartment
patella를 retraction후
MCL 을 MCL retractor로 retract하고 다리를 slight external rotation of leg 하면 전체적으로 좋은 시야가 나온 다

8. Adjustment and fixation of tibia guide
Guide의 shaft를 tibia crest에 맞추어coronal alignment결정후 하나의 screw를 박아서 coronal alignment를 정한다
Guide의 center를 술전 tibia axis 만나는 곳에 둔다 .

9. balancing
After removal of the osteophytes, the varus deformity can be corrected.
Scott
Insall 4th edit

10. 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
수술 전 계획 대로

11. Slope of tibia usually between 5° and 7° of posterior slope
The natural slope is restored, but a posterior slope greater than 7 degrees is not recommended
Argenson, Jean-Noel A MD; Parratte,
corr 464 Nov 2007 P32
Scott
Insall 4th edit

12. Posterior Slope of the Tibial Implant and the Outcome of Unicompartmental Knee Arthroplasty
Philippe Hernigou and Gerard Deschamps
J Bone Joint Surg Am. 2004;86:

13. Horizontal cut MCL retractor 로 MCL protection요하며.
역시 너무 깊이 들어가 N_V 손상주지 않도록 조심 해야한다

14. 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

15. the direction of the sagittal cut
determined by the condyle itself
parallel to the wear pattern of the tibia
toward Femoral head in flexion (임홍철)
Having the patella not dislocated from the patellar groove is necessary for an appropriate tracking of component congruity.
Richard D. Scott
Bobby로marking하면 좋다
이범구
Scott
Insall 4th edit

16. It is very important to avoid overstuff & overcorrection
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

17. 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

18. Ideal balance med lat extension 2mm flexion 3mm 4mm
ICL AAOS Richard A Berger P47

19. flexion gap balancing
performed by sliding a spacer block representing the thickness of the tibial component
To balance the flexion gap, the thigh should be lifted with one arm.
The block should slide backward with mild resistance.
1 to 2 mm laxity is suggested.in medial UKA
Scott
Insall 4th edit

20. the proper thickness of the tibial component
. After medial compartment replacement, the medial joint space should open up 1 or 2 mm when valgus stress is applied with the knee in full extension.
. The deformity should not be overcorrected
insall 4th edit Wolfgang FitzRichard D. Scott

21. Important techn in UKA
Our results seem to reflect those seen in registries confirming an earlier higher revision rate and highlight the technical issues of overstuffing the compartment,
The main issues in technique were overstuffing the medial compartment usually as a result of under resection of tibial bone and/or MCL attenuation
The desire for maximal bone preservation cannot supercede the need for adequte bone resection and varus resection on the tibial side aggravated this situation and must be avoided
Initial Experience With the Oxford Unicompartmental Knee Arthroplasty
Geoffrey F. Dervin MD, FRCSC, a, Chris Carruthers MD, FRCSCa, Robert J. Feibel MD, FRCSCa, Alan A. Giachino MD, FRCSCa, Paul R. Kim MD, FRCSCa and Peter R. Thurston MD, FR JA February 2011, Pages

22. 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

23. If the flexion gap is too tight; 2nd step
or The slope should be slightly
increased

24. 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

25. 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
Tilt안 되게 자른 다
자른 골의 두께 를 측 정, shim이 위로 안 가게 check

26. Slope of distal femur cutting
For example, for a 5-degree tibia slope
the knee should be held in 5 degrees of flexion to fix the distal femoral cutting block.
Because If the distal femoral cutting block is pinned in full extension, the knee will hyperextend 5 degrees, as determined by the tibial slope
Scott
Insall 4th edit

27. Distal cut가 flex해지면 flex gap이 tight해진다

28. The entrance hole of the distal femur
centered above the roof of the intercondylar notch.
often requires bringing the knee to lower degrees of flexion; otherwise, in flexion, the unyielding patella might induce incorrect alignment of the intramedullary guide
Argenson, Jean-Noel A MD; Parratte,
corr 464 Nov 2007 P32

29. Distal femoral cut
video

30. Scuderi Insall 4th edit The drilling of the femoral medullary canal
through a short incision often requires bringing the
knee to lower degrees of flexion; otherwise, in flexion, the
patella might induce incorrect alignment of the intramedullary
guide.

31. the distal femoral cut ;Angle
calculated on the full weightbearing view
the angle between the anatomic and mechanical axis is chosen
This angle is usually 4° to 6°

32. The amount of bone resected
corresponds to the femoral prosthesis thickness
Scuderi Insall 4th edit
the deeper resection (line A)
results in less valgus than line B (3 degrees versus 5 degrees).
This also allows for more space in full extension
For valgus knees, it is often necessary to use a more proximal
distal femoral cut

33. The Extramedullary Spacer Block Technique
Figure A, After tibial resection the gap is checked with a spacer block. B, The appropriate spacer block is inserted into the joint space. C, The spacer block and distal cutting guide assembly are shown. D, The distal cutting guide is secured to the distal femur. E, Alignment is confirmed with the appropriate block and rod.
Scuderi Insall 4th edit

34. Finishing cutting guide placement
Femur finishing guide is inserted in 90 degree flexion .

35. Finishing cut ;Size If the size is proper,
1 to 2 mm of exposed bone . At the anterior edge

36. The anterior extent of the weightbearing surface
defined by the junction between the eburnated bone of the femoral condyle and the intact cartilage remaining in the trochlear groove.

37. Finishing cut ;Size
There should be 1 to 2 mm of exposed bone along the anterior edge of the guide.
The leading edge of the femoral component must be countersunk into this junction to prevent patellar impingement during flexion of the knee
If the finishing guide appears to be between sizes, it is preferable to pick the smaller size.
Scuderi Insall 4th edit

39. Mediolateral dimension.
For the correct mediolateral position, The guide should be placed in the center of the femoral condyle,mediolaterally

40. 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

41. Finishing cut ; To assess the amount of external rotation, .
the center of the tibial trial is marked with a Bovie on the femoral condyle in different positions (90, 60, 30, 0 degrees)..
The femoral prosthesis should be only slightly externally rotated
External rotation of more than 5 degrees is not recommended so that the possibility of edge loading is minimized.
Scott
Insall 4th edit

42. Finishing cut; rotation
.This guide should also be rotationally set so that the posterior surface is parallel to the resected tibia
Guide를 tibia spacer넣고 그위에 finishing guide넣으면 편할 듯
이범구
Scuderi Insall 4th edit

43. 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

44. Posterior condyle resection
. The posterior condylar bone should be resected to at least the thickness of the metallic implant.
It is better to resect slightly too much of the posterior condyle than too little to avoid making the components too tight in flexion
Scott
Insall 4th edit

45. removal of any posterior osteophytes
Once the posterior cut has been made and the cutting guide removed, removal of any posterior osteophytes is necessary using a curved osteotome to increase the range of flexion and avoid any posterior impingement with the polyethylene in high flexion
Scott
Insall 4th edit

46. The femoral component should be placed
in the center of the mediolateral dimension of the femoral condyle,. when the knee is extended
. The femoral component should extend far enough anteriorly to cover the weightbearing surface that comes in contact with the tibia in full extension.
the articulating surfaces of the two components are rotationally congruent during weightbearing . in full extension.
It should not be judged while the knee is flexed and the patella is everted.
Scott
Insall 4th edit

47. 1st alignment check

48. Post. Condyle trimming to avoid impingement posteriorly

49. The final preparation of the tibia; exposure
The leg is externally exposed, while the MCL is retracted to expose the whole medial compartment
The leg is externally exposed, while the MCL is retracted to expose the whole medial compartment

50. 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 걸치므로 조기collapse가 온 다 .

52. *Templating in estimating size of unicondylar KA
intra and inter observer reliability가  poor
accuracy of templating in TKA ;
    50-57%
Heal and Blewitt JA 17;90,2002
(Bothra JOAr Sept'03P 780)

53. The size of the tibial tray
best compromise between maximal tibial coverage and overhang, which might induce pain in the soft tissues.
overhang, which might induce pain
in the soft tissues
Argenson, Jean-Noel A MD; Parratte,
corr 464 Nov 2007 P32

54. Tibia preparation; tibia의 posterior margin을 정확히 파악 후 하여야 하며
tibia guide 넣고 일시적으로 tensor로 눌러서 고정후 the keel 을특수한 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

55. Alignment check

56. Tibia cement Staged cementing
Avoid tilt of tibia plate especially posterior ( which result in tightness in flexion.
adequate exposure of posteromedial tibia
adequate sizing

57. 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.

58. 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

59. cement Sequence;The tibial component
-will be cemented first with the knee
Tibia cementing
-position; in full flexion and externally rotated for a medial UKA.
-Cement should be removed posterioly
Femoral cementing ;and posterior cement removal
cement is done in flexion but
Once the femoral implant has been cemented, bringing the knee close to extension with the polyethylene inserted last helps remove any posterior cement.
Argenson, Jean-Noel A MD; Parratte,
corr 464 Nov 2007 P32

60. Important techn in UKA
inadequate cementation technique, and strict adherence to patient selection.
issues of inappropriate patient selection and technique did account for some early failures
The other technical issue related to debonding of the femoral component and care must be taken to ensure the cement mantle is evenly pressurized at 45° flexion to avoid tilting in flexion or extension while also ensuring adequate cement mantle on the posterior undersurface and in the femoral hole for the peg
Initial Experience With the Oxford Unicompartmental Knee Arthroplasty
Geoffrey F. Dervin MD, FRCSC, a, Chris Carruthers MD, FRCSCa, Robert J. Feibel MD, FRCSCa, Alan A. Giachino MD, FRCSCa, Paul R. Kim MD, FRCSCa and Peter R. Thurston MD, FR JA February 2011, Pages

61. Liner insertion
In flexion , the liner is inserted with hand

63. 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:

64. Lateral Unicompartmental Replacement

65. 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 Jan'06 J arthroplasty
Donald W. Pennington, John J. Swienckowski, William B. Lutes and Gregory N. Drake

66. 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

67. 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

68. The polyethylene insert is often thicker than for the medial side,
When the lateral arthrotomy is performed, visualization of the joint is often easier than on the medial side because of the natural mobility of the lateral tibiofemoral joint.
The tibial resection should stay minimal, because the disease is more often on the femoral side..
It is often necessary to mark the correct alignment in extension rather than in flexion to avoid medial edge loading and impingement between the femoral implant and the tibial spines.
The polyethylene insert is often thicker than for the medial side,
but the principle of undercorrecting the deformity for all cases of lateral UKA remains the basis for successful long-term results
Jean-Noel A
Insall 4th edit

69. On the lateral condyle the patella is more vulnerable to impingement on the leading edge of the femoral component. This problem can be avoided by undersizing the femoral component
Insall P 1416

70. lateral UKA
ESSKA 2008
The in vivo kinematic evaluation of patients with lateral UKA found a greater posterior displacement of the femor during flexion-> dome shaped implant is advantageous
Argenson JN, Komistek RD, Aubaniac JM, et al: In vivo determination of knee kinematics for subjects implanted with a unicompartmental arthroplasty. J Arthroplasty 17:1049, 2002

71. Thank you for your attention