8 Surgical technique Soft Tissue and Bone Tendon Bone Femoral half tunnel: mm depthTibial tunnel
9 Surgical techniqueHarvest the Semitendinosus and Gracilis tendons
10 Surgical technique Fold the two grafts over a strong suture (Ethibond #4 or 5)
11 Surgical techniqueWhip stitch (Ethibond #2) the looped-over part of the graft as shown: it is important to create a secure and compact bundle
12 Surgical techniqueMark the graft at 30 mm for later reference when placing it into the femoral half-tunnel
13 Surgical techniqueChoose the femoral rod of the same diameter of the tunnelAttach it to the guide frame
14 Surgical techniqueInsert the guide (attached to the appropriate size femoral rod) into the femoral tunnel until it touches the end
15 Surgical techniqueAssemble the sleeve over an interlocking trocar: note that the trocar is much longer then the sleeveinterlocking trocarsleeve
16 Surgical techniqueNote how the trocar blocks itself: the sleeve-trocar assembly can rotate together
17 Surgical techniqueDrill the sleeve-trocar assembly through the two holes of the guide into the lateral side of the femur
18 Surgical techniqueRemove the guide frame from the knee, leaving only the two sleeves in the lateral aspect of the femur.
19 Surgical techniqueNote that a lot of saline solution comes out: this shows the right placement of the sleeves.
20 Surgical techniqueTo verify furthermore the right placement of the two sleeves, use the scope and a trocar.
21 Surgical techniquePull the graft into the tunnel using a guide wire
22 Surgical techniqueDuring the graft placement, the saline outflow stops: this shows that the graft has filled the tunnel
23 Surgical techniqueInsert the RIGIDfix cross pins into the sleeves using the stepped pin insertion rod and mallet.
24 Surgical techniqueDuring the pin insertion the surgeon feels the press-fit sensation: the pin crosses through the soft tissue fibers and presses them towards the tunnel surface.
25 Surgical technique Remove the sleeves. The graft is now fixed in the femoral tunnel by two parallel absorbable pins.
26 Surgical techniquePay attention to remove the sleeves: pull it with the removal-tool in the straight direction, without twisting or bending.
27 Surgical technique Bone Tendon Bone Graft the central third from the patellar tendonPlace one drill hole in the femoral plug for application of a stay suture
28 Surgical technique Bone Tendon Bone Assemble the sleeve over an interlocking trocar: note that the trocar is about so long as the sleeveinterlocking trocarsleeve
29 Surgical technique Bone Tendon Bone Pull the graft is inside the half tunnelDrill the longer trocar through the femoral sleeves in order to create the holes on the bone plug
30 SUMMARIZING Femoral half tunnel: 25-30 mm lenght Place the guide/femoral rod into the femoral half tunnelSoft TissueBone Tendon BoneDrill the two sleeves into the lateral side of the femurDrill the two sleeves into the lateral side of the femurPull the graft in placePull the graft in placeInsert the cross pinsDrill the bone plugInsert the cross pins
32 In the ST technique:there is “press-fit” not “hanging on”!
33 there is “press-fit” not “hanging on”! In the ST technique:there is “press-fit” not “hanging on”!7 mm7 mm3.3 mm10.3 mm3.3 mm10.3 mm7 mm
34 The dimensions of femoral rod and B-T-B pins5.8 mm9 mm10.3 mm16.5 mm17.8 mm19.8 mm30 mm30 mm25 mmN.B.: 2.7 mm is the diameter of Bone Tendon Bone pins
35 Technical data for STUltimate loadR = 623 NStiffnessK = 60 N/mm
36 Technical data for BTBUltimate loadR = 424 NStiffnessK = 74 N/mm
37 Cyclic loading tests Cyclic loading Average migration 1,4 mm Load n = 1000 cicles150 N10 NTimeAverage migration1,4 mm
38 Orientation testsThe ST tendons are whipstitched at the looped end, forming a tight bundle that is “press-fit” placed into the femoral tunnel. This allows RIGIDfix absorbable pins to cross the graft in any plane and provide rigid fixation.