Upload
hope-chapman
View
221
Download
1
Embed Size (px)
Citation preview
duringduringLCA LCA reconreconsstructiontruction
RResorbable transcondylesorbable transcondylararsystemsystem
for femoral fixationfor femoral fixation
The productThe product
STST: Dr. Daniel J. McKernan, : Dr. Daniel J. McKernan, Toledo, Ohio, USAToledo, Ohio, USA
BTBBTB: Dr. Paul H. Marks, : Dr. Paul H. Marks, Toronto, Ontario, CANToronto, Ontario, CAN
Created by:Created by:
42 mm42 mm
42 mm42 mm
3.3
mm
3.3
mm
2.7
mm
2.7
mm
The “Cross Pin”The “Cross Pin”
Bone-Bone-Tendon-BoneTendon-Bone
Soft-TissueSoft-Tissue
Material: PLA, Polilactic AcidMaterial: PLA, Polilactic AcidReabsorption: 2-4 yearsReabsorption: 2-4 yearsIdrolysis (COIdrolysis (CO22 + H + H22O)O)
The instrumentsThe instrumentsSoft Soft TissueTissue
Femoral rod:7, 8, 9, 10 mm
The instrumentsThe instrumentsBone-Tendon-BoneBone-Tendon-Bone
Femoral rod:9, 10, 11, 12 mm
Stepped trocar: to drill the bone plug
The sterile kitThe sterile kitTwo pinsTwo pins
One interlocking trocarOne interlocking trocar
Two sleevesTwo sleeves
The sterile kitThe sterile kit
Surgical techniqueSurgical techniqueSoft Tissue and Bone Tendon Soft Tissue and Bone Tendon BoneBone
Tibial Tibial tunnel tunnel
Femoral half Femoral half tunnel: 25-30 mm tunnel: 25-30 mm depth depth
Surgical techniqueSurgical technique
Harvest the Semitendinosus and Gracilis Harvest the Semitendinosus and Gracilis tendonstendons
Surgical techniqueSurgical technique
Fold the two grafts over a strong Fold the two grafts over a strong suturesuture(Ethibond #4 or 5)(Ethibond #4 or 5)
Whip stitch (Ethibond #2) the Whip stitch (Ethibond #2) the looped-over part of the graft as looped-over part of the graft as shown: it is important to create a shown: it is important to create a secure and compact bundlesecure and compact bundle
Surgical techniqueSurgical technique
Mark the graft at 30 mm for later Mark the graft at 30 mm for later reference when placing it into the reference when placing it into the femoral half-tunnelfemoral half-tunnel
Surgical techniqueSurgical technique
Choose the Choose the femoral rod of femoral rod of the same the same diameter of the diameter of the tunneltunnel
Attach it to the Attach it to the guide frameguide frame
Surgical techniqueSurgical technique
Insert the guide Insert the guide (attached to the (attached to the appropriate size appropriate size femoral rod) into femoral rod) into the femoral tunnel the femoral tunnel until it touches until it touches the endthe end
Surgical techniqueSurgical technique
Assemble the sleeve over an Assemble the sleeve over an interlocking trocar: note that the interlocking trocar: note that the trocar is much longer then the sleevetrocar is much longer then the sleeve
interlocking trocar sleeve
Surgical techniqueSurgical technique
Note how the trocar blocks itself: the Note how the trocar blocks itself: the sleeve-trocar assembly can rotate sleeve-trocar assembly can rotate togethertogether
Surgical techniqueSurgical technique
Surgical techniqueSurgical technique
Drill the Drill the sleeve-sleeve-trocar trocar assembly assembly through the through the two holes of two holes of the guide the guide into the into the lateral side lateral side of the femurof the femur
Surgical techniqueSurgical technique
Remove the Remove the guide frame guide frame from the from the knee, leaving knee, leaving only the two only the two sleeves sleeves in the in the lateral aspect lateral aspect of the femur.of the femur.
Surgical techniqueSurgical technique
Note that a lot of saline solution Note that a lot of saline solution comes out: this shows the right comes out: this shows the right placement of the sleeves.placement of the sleeves.
Surgical techniqueSurgical technique
To verify furthermore the right placement To verify furthermore the right placement of the two sleeves, use the scope and a of the two sleeves, use the scope and a trocar.trocar.
Surgical techniqueSurgical technique
Pull the graft Pull the graft into the into the tunnel using tunnel using a guide wirea guide wire
Surgical techniqueSurgical technique
During the graft placement, the saline During the graft placement, the saline outflow stops: this shows that the graft outflow stops: this shows that the graft has filled the tunnelhas filled the tunnel
Surgical techniqueSurgical technique
Insert the RIGIDfix Insert the RIGIDfix cross pins into the cross pins into the sleeves using the sleeves using the stepped pin insertion stepped pin insertion rod and mallet.rod and mallet.
Surgical techniqueSurgical technique
During the pin insertion the surgeon During the pin insertion the surgeon feels the press-fit sensation: the pin feels the press-fit sensation: the pin crosses through the soft tissue fibers crosses through the soft tissue fibers and presses them towards the tunnel and presses them towards the tunnel surface.surface.
Surgical techniqueSurgical technique
Remove the Remove the sleeves.sleeves.The graft is now The graft is now fixed in the fixed in the femoral tunnel femoral tunnel by two parallel by two parallel absorbable pins.absorbable pins.
Surgical techniqueSurgical technique
Pay attention to remove the sleeves: Pay attention to remove the sleeves: pull it with the removal-tool in the pull it with the removal-tool in the straight direction, without twisting or straight direction, without twisting or bending.bending.
Surgical technique
Bone Tendon Bone
Graft the central Graft the central third from the third from the patellar tendonpatellar tendon
Place one drill Place one drill hole in the hole in the femoral plug for femoral plug for application of a application of a stay suturestay suture
Surgical techniqueBone Tendon Bone
interlocking trocar sleeve
Assemble the sleeve over an Assemble the sleeve over an interlocking trocar: note that the interlocking trocar: note that the trocar is about so long as the sleevetrocar is about so long as the sleeve
Surgical techniqueSurgical technique
Bone Tendon Bone Tendon BoneBone
Drill the longer trocar through Drill the longer trocar through the femoral sleeves in order to the femoral sleeves in order to create the holes on the bone create the holes on the bone plugplug
Pull the graft is inside the half Pull the graft is inside the half tunnel tunnel
SUMMARIZINGSUMMARIZINGFemoral half tunnel: 25-30 mm Femoral half tunnel: 25-30 mm lenghtlenght
Place the guide/femoral rod into the femoral half Place the guide/femoral rod into the femoral half tunneltunnel
Drill the two sleeves Drill the two sleeves into the lateral side of into the lateral side of the femurthe femur
Drill the two sleeves Drill the two sleeves into the lateral side of into the lateral side of the femurthe femur
Soft TissueSoft Tissue Bone Tendon Bone Tendon BoneBone
Pull the graft in placePull the graft in place Pull the graft in placePull the graft in place
Insert the cross pinsInsert the cross pins
Insert the cross pinsInsert the cross pins
Drill the bone plugDrill the bone plug
The The PRESSPRESS--FITFIT
In the ST technique:In the ST technique:there is “press-fit” not “hanging on”!there is “press-fit” not “hanging on”!
7 m
m3
.3 m
m
10
.3 m
m
7 mm 7 mm
10
.3 m
m
3.3
mm
In the ST technique:In the ST technique:there is “press-fit” not “hanging on”!there is “press-fit” not “hanging on”!
30
mm
9 m
m
16
.5 m
m
30
mm
5.8
mm
19
.8 m
m
10
.3 m
m
17
.8 m
m
25 mm
The dimensions of femoral rodThe dimensions of femoral rodand B-T-B pinsand B-T-B pins
N.B.: 2.7 mm is the diameter of Bone Tendon Bone pins
Ultimate loadUltimate load
0
100
200
300
400
500
600
700
Ultimate load for ST (Newton)
RIGIDfixEndoButtonTransFix
0
20
40
60
80
100
120
Stiffness for ST (N/mm)
RIGIDfixEndoButtonTransFix
StiffnessStiffness
R = 623 NR = 623 N
K = 60 N/mmK = 60 N/mm
Technical data for STTechnical data for ST
Technical data for BTBTechnical data for BTB
Ultimate loadUltimate load
0
10
20
30
40
50
60
70
80
90
Stiffness for BTB (N/mm)
RIGIDfixBioScrew
StiffnessStiffness
0
100
200
300
400
500
600
Ultimate load for BTB (Newton)
RIGIDfixBioScrew
R = 424 NR = 424 N
K = 74 K = 74 N/mmN/mm
Cyclic loading testsCyclic loading tests
Average migrationAverage migration
0.14
0.43
1.12
1.40
2.09
2.38
3.07
3.36
Migration for ST (mm)
RIGIDfixEndoButtonTransFix
1,4 mm1,4 mm
Cyclic Cyclic loadingloading
LoadLoad
TimeTime
150 N150 N
10 N10 N
n = 1000 ciclesn = 1000 cicles
Orientation Orientation teststests
The ST tendons are whipstitched at the looped The ST tendons are whipstitched at the looped end, forming a tight bundle that is “press-fit” end, forming a tight bundle that is “press-fit” placed into the femoral tunnel. This allows placed into the femoral tunnel. This allows RIGIDfix absorbable pins to cross the graft in RIGIDfix absorbable pins to cross the graft in any plane and provide rigid fixation.any plane and provide rigid fixation.