j.l lerat, b. moyen, i. bénareau e. berthonnaud, j. dimnet service de chirurgie orthopédique &...
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J.L Lerat, B. Moyen, I. Bénareau
E. Berthonnaud, J. Dimnet Service de Chirurgie Orthopédique &
Laboratoire de Biomécanique du Mouvement
Centre Hospitalier Lyon-Sud
INNEX-Knee INNEX-Knee The Lyon experienceThe Lyon experience
J.L Lerat, B. Moyen, I. Bénareau
E. Berthonnaud, J. Dimnet Service de Chirurgie Orthopédique &
Laboratoire de Biomécanique du Mouvement
Centre Hospitalier Lyon-Sud
INNEX-Knee INNEX-Knee The Lyon experienceThe Lyon experience
Aim of the presentation
1 - Preliminary results (1 to 3 years)
2 - Anterior-posterior laxity 3 - Mobility of the plateau
INNEX-KneeINNEX-KneeThe Lyon experienceThe Lyon experience
1st Pilot study (April 1998 - Nov. 1998)
• Innex knee cemented femur and tibia :
30 cases (20 CR - 10 PS)
INNEX-KneeINNEX-KneeThe Lyon experienceThe Lyon experience
1st Pilot study (April 1998 - Nov. 1998)
• Innex knee cemented femur and tibia :
30 cases (20 CR - 10 PS)
2nd Pilot study (Nov. 1999 - 0ct. 2000)
• Innex knee non cemented femur :
20 cases (10 CR - 10 UCOR)
+ further experience : 23 cases
73 cases • 44 F - 29 M• Age : 69 ± 10 years (26-88)
• Etiology2 R. A, 1 SVNH
2 hemophilic arthropathies1 Paget’s disease68 gonarthrosis
- 14 previous osteotomies - 6 previous surgery (2 ACL,1 fract, 2 patella)
INNEX-Knee INNEX-Knee The LYON experienceThe LYON experience
Some cases are particularly difficult for a pilot study
INNEX-KneeINNEX-Knee
These difficulties explain :
Op. time : 90 mn ± 19 (55-145)
Tibial tuberosity ost : 10 cases
Immediate weight bearing
Discharge : 7 days
Flexion after 7 days : 80°
INNEX-KneeINNEX-Knee
PCL preservation : 42
Postero-stabilisation : 12
UCOR : 19
PCL normal : 73 (100 %)
ACL normal : 45 (61.5 %)
ACL ruptured : 28 (38.5 %)
ComplicationsComplications
• 1 Reflex Sympathic Dystrophy • 11 Deep Veinous Thombosis• 1 fracture of tibial tubercule (fall in stairs after 1 month) • 1 skin necrosis (after 8 op with 7 skin incisions : arthrodesis)• 0 infection • 4 Manipulations under Gen. anest.
Functional resultsFunctional results
Internat. Knee Society Score(200 pts)
Pre op : 116 ± 27 (50-173)
Post op : 184 ± 24 (87-200)
Bad : 1 Correct : 7 % Good : 20 % Excellent : 73 %
n = 30 cases (1 year)
Flexion = 106° ± 18
(45° - 140°)
Extension : 0° : 55 cas - 5° : 6 cas -10° : 5 cas
After 2 monthsn = 66
• 45-80° : 5 • 85°-95° : 8• 100°-105° : 12• 110°-115° : 14• 120°-125° : 16• 130°-135° : 9• 135°-140° : 2
Mobility Mobility
Follow-up : 1 yearn = 34
• 45°-80° : 2• 90°-95° : 2• 100°-105° : 4• 105°-110° : 6• 110°-120° : 4• 120°-125° : 7• 125°-130° : 3• 130°-140° : 6
Mobility Mobility
Flexion = 112°± 18°
(45° - 140°)
Extension : -1° ± 3°
0° : 29 cases
- 5° : 2 cases -10° : 3 cases
Follow-up : 1 yearn = 34
• 45°-80° : 2• 90°-95° : 2• 100°-105° : 4• 105°-110° : 6• 110°-120° : 4• 120°-125° : 7• 125°-130° : 3• 130°-140° : 6
Mobility Mobility
112°± 18°
> 120° : 47 %
Anatomical resultsAnatomical results
Varus knees (n = 60)
HKA = 172° ± 5°
(160° - 180°)
preop
Varus
HKA = 179° ± 2°
(173° - 186°)
178 to 182° : 88 %
postopH
K
A
HKA= mechanical axis
Varus knees (n = 60)
HKA = 172° ± 5°
(160° - 180°)
Valgus knees (n = 13)
HKA = 184° ± 3°
(181° - 189°)
preop
varus
HKA = 179° ± 2°
(173° - 186°)
Valgus
HKA = 180° ± 3°
(178° - 184°)
postopH
K
A
Anatomical resultsAnatomical results
Precision of the cuts
F (femur A-P) : 90° ± 1
T (tibia A-P) : 89° ± 2
Femur lateral : 88° ± 2
Tibia lateral : 87° ± 2
n=71
F angle : 90° ± 1°
Distal fémoral cutDistal fémoral cut
• 87° : 1• 88° : 8• 89° : 10• 90° : 27• 91° : 10• 92° : 11• 93° : 4
n = 71
F
F angle : 90° ± 1°
Distal femoral cutDistal femoral cut
• 87° : 1• 88° : 8• 89° : 10• 90° : 27• 91° : 10• 92° : 11• 93° : 4
n = 71
F
93%
HKS angle : 6° ± 2
• 2° : 1 case
• 3° : 2
• 4° : 6
• 5° : 29
• 6° : 14
• 7° : 9
• 8° : 6
• 9° : 2
• 10° : 2
• 11° : 2
n = 73
H
K
S
Important pre operative measurement to do a
precise distal cut
Tibial cutTibial cut
• 85° : 1• 86° : 1• 87° : 9• 88° : 14• 89° : 8• 90° : 25• 91° : 7• 92° : 3• 93° : 3 n = 71
T angle : 89° ± 2°
Tibial cutTibial cut
• 85° : 1• 86° : 1• 87° : 9• 88° : 14• 89° : 8• 90° : 25• 91° : 7• 92° : 3• 93° : 3 n = 71
T angle : 89° ± 2°
81%
Position of the componentsPosition of the components
Inclination of femoral component : F lateral
88° ± 2°• 85° : 11
• 86° : 7
• 87° : 13
• 88° : 8
• 89° : 5
• 90° : 24
• 92° : 1
n = 71
The intramedullary axis is not always the recommended guide for anterior and posterior cuts
Sometimes, metaphyseal axis should be better
Position of the componentsPosition of the components
82° : 2
83° : 3
84° : 9
85° : 5
86° : 9
87° : 18
88° : 9
89° : 1
90° : 11
91° : 3
Inclination of tibial component : T lateral
87° ± 2
Instrumentation takes into account the mean anatomical slope : 6° (or 84°)
Position of the componentsPosition of the components
82° : 2
83° : 3
84° : 9
85° : 5
86° : 9
87° : 18
88° : 9
89° : 1
90° : 11
91° : 3
Inclination of tibial component : T lateral
87° ± 2
The difference comes probably from the fact that the measurements are done on short X-ray films and not on
the complete tibia
N = 73
90°±1 88°±2
89°±2 87°±2
Other TKAs INNEX-knee
In conclusion, the precision of the cut is satisfactory
All the cases are included (learning curve)
no difference between Innex and other types of TKR in our experience
PatellaPatella
• 64/73 without resurfacing
• Thickness of bone = 22 ± 2 mm
• 9 patella resurfaced
• Blackburn index p. op = 0.76 ± 0.16
• Patella centered : 68 cases
• Subluxation (1 to 3 mm) : 5 cases
Only 1 case of secondary patellar resurfacing
• 9 patellar resurfacing (12 %)
• Thickness of bone = 22 ± 2 mm
• Post-op thickness of bone = 14 ± 1 mm
PatellaPatella
Interest of the CSTI used successfully with the « Natural knee »
CSTI
530 knees
follow-up max. : 4.5 Y
The short stem of Innex is an advantage in TKA after osteotomy
UCOR
In case of severe valgus after HTO the short stem of Innex permits to associate TKR and a new osteotomy in the same time
Innex CR + osteotomy
Extension Post drawer Ant drawer
• Study of anterior and posterior drawer
• Study of the mobility of MB
– Anterior-posterior translation during flexion
– Anterior-posterior translation during radiological drawer-test
– Rotation
Second part
« Knee instability after injury to the anterior cruciate ligament
Quantification of the Lachman test »
JL Lerat, B Moyen, F Cladière, JL Besse, H Abidi
J. Bone Joint Surgery VOL. 82-B, N°1, January 2000, 42-47.
Radiological anterior drawerRadiological anterior drawer
• Flexion : 20°Flexion : 20°• 9 kg load9 kg load• Free translation Free translation • Free rotation Free rotation
Radiological anterior drawerRadiological anterior drawer
• Flexion : 20°Flexion : 20°• 9 kg load9 kg load• Free translation Free translation • Free rotation Free rotation
Anterior drawer6.5 ± 5.4 mm (6-16)
n = 34
Posterior drawer Posterior drawer
Test used for PCL rupture :Test used for PCL rupture :
Lateral view with harmstrings Lateral view with harmstrings contractedcontracted
Flexion : 70°Flexion : 70°
Posterior drawer7.3 ± 4.7 mm (1-15)
n = 65
UCOR
Post drawer Ant drawer
Post drawer : 10 mm ± 4 Ant drawer : 4.3 mm ± 5
n = 14 n = 10
Study of the mobility of mobile bearing
Anterior-posterior translation
Combination of translation and rotation
Study of the position of the Mobile plateau
– In full extension in one leg standing position
– At 30° of flexion in one leg standing position
– AT 50-60° of flexion in one leg standing position
Extension in standing position
The MB is situated post. to metal : 2.2 ± 2.4 mm
33 cases : posteriorly (3.4 mm)
7 cases : anteriorly (3.7 mm)
n = 40
Mobility of mobile bearing
Flexion 30° in standing position
The MB is situated post to metal : 2.7 ± 2.4 mm
17 cases : behind (4 mm)
4 cases : before (3 mm)
n = 21
Flexion 50° in standing position
The plateau is always situated post to metal : 4.3 ± 2.7 mm
n = 9
Post drawer : 7.3 ± 4.7 mm
• M B situated 1.7 mm post to metal
35 cases post : 4.5 mm18 cases ant : 2.8 mm
n = 53 cases
Ant drawer : 6.5 ± 5.4 mm
• M B situated 4 mm post. to metal
3 cases ant : 2.5 mm24 cases post : 4.4 mm
n = 24 cases
Position of the mobile bearing in ant. and post. drawer
Posterior drawer + Anterior drawer
Total A-P translation of Mobile Bearing : 5.7 ± 3.9 mm (0.5 - 14.2) range : 13.7 mm
X-ray Mobility StudyINNEX CR & INNEX UCOR
E. Berthonnaud, J. Dimnet
Laboratoire de Biomécanique du mouvementCentre Hospitalier Lyon-Sud
3 balls in the polyethylene
Study of the rotation - Preliminary results
Calculation of the PE mobility with one X-ray
X-ray plate
X-ray source
INNEX with 3 steel balls embedded in the PE
.
Known :- Distance between X-ray source and X-ray plate.- Position of the X-ray source on the X-ray.
Known :- The size of the INNEX (tibial base plate)- The interdistances between balls in PE.
Calculated:- The rotation between the PE and the tibial base plate.- The translation t between the PE and the tibial base plate.
Measured :
The position of rotation axis
The position of the balls
The position of the tibial plots
Mobility of the PE plateau vs tibial component(first results)
10.5°
8°
4.5°
3.5°
1°
2°
3,5°
Total amount of rotation from full extension to 50° of flexion in standing position
The study is just starting and should be multicentric
Tiroir antérieur et pente tibiale favorisant la bascule
1 an