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Quadruple Semitendinosus Graft Construct and Suspensory Button Fixation for Anterior Cruciate Ligament Reconstruction
Quadruple Semitendinosus Graft Construct and Suspensory Button Fixation for Anterior Cruciate Ligament Reconstruction Alcindo Silva, M.D., and Ricardo Sampaio, M.D.
Abstract: Surgical techniques for anterior cruciate ligament reconstruction are evolving, becoming less invasive, with fewer and smaller incisions, preservation of knee bone stock and tendons at the donor site, and better graft positioning and fixation. We describe an anterior cruciate ligament reconstruction technique that aims to preserve bone stock and spares the gracilis. The semitendinosus graft construct is prepared in a quadruple way and fixed with a cortical button in both tunnels, with increased stiffness and resistance of the graft construct. The tibial tunnel is filled at the end of the operation with a bone dowel, keeping the bone stock intact. This technique is safe, with a short learning curve; preserves the gracilis; saves bone; and increases the stiffness and resistance of the tibial fixation.
A
rthroscopic anterior cruciate ligament (ACL) reconstruction is a common procedure. Surgical techniques are evolving, becoming less invasive, with fewer and smaller incisions, preservation of knee bone stock and tendons at the donor site, and better graft positioning and fixation.1 We describe a new ACL reconstruction technique that aims to preserve bone stock and uses only the semitendinosus tendon for graft preparation. The quadruple semitendinosus graft construct is prepared in a novel way and fixed with a new cortical suspensory button in the tibial tunnel, with increased stiffness and resistance of the graft construct (Video 1, Table 1).
Surgical Technique Patient Positioning The patient is placed in the supine position, with a post to assist with achieving a valgus moment, as well as a foot and thigh holder to hold the leg at 90 of flexion. From the Orthopedics Department, Hospital Militar D. Pedro V (A.S.); and Hospital Lusiadas Porto (R.S.), Porto, Portugal. The authors report the following potential conflict of interest or source of funding: A.S. receives support from Biomet. Received May 9, 2015; accepted July 31, 2015. Address correspondence to Alcindo Silva, M.D., Orthopedics Department, Hospital Militar D. Pedro V, Avenida da Boavista, 4050-113 Porto, Portugal. E-mail: [email protected] Ó 2016 by the Arthroscopy Association of North America 2212-6287/15435/$36.00 http://dx.doi.org/10.1016/j.eats.2015.07.030
Graft Harvest The semitendinosus graft is harvested through a traditional approach with an oblique incision over the pes anserinus tendons. Graft Preparation Both free ends of the semitendinosus are stitched over a length of 20 mm, using No. 2 ExpressBraid suture (Zimmer Biomet, Warsaw, IN). Two adjustable-length loop cortical button devices are used: ToggleLoc (Zimmer Biomet), for the femur, and ToggleLoc XL Inline (Zimmer Biomet), for the tibia (Fig 1A). The tendon graft is symmetrically folded over the tibial cortical button loop (Fig 1B), and the doubled graft is passed through the femoral cortical button loop and is symmetrically folded again (Fig 1C). One free end strand of the graft passes through the tibial button loop, and both free ends of the graft are tied together (Fig 1D). Then, the same sutures are tied over the graft itself with 4 knots (Fig 1E). Finally, the graft construct is placed on the graft tensioning table (Zimmer Biomet), and the 4-stranded graft is reinforced on the tibial side with No. 2 ExpressBraid cerclage-type suture. To achieve this, a buried-knot technique is used, starting from the inside of the graft and stitching outward, through the second, third, and fourth graft limbs. The suture is then wrapped around the graft and stitched back through the first graft limb. The suture is tied with 3 manual knots (Fig 1F). Pre-tensioning of the graft construct at 300 N is applied for 2 minutes in the graft station.
Arthroscopy Techniques, Vol 4, No 6 (December), 2015: pp e801-e806
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Table 1. Key Points for ACL Reconstruction Technique Only the semitendinosus is harvested, with a length of at least 24 cm, to obtain a quadruple graft construct measuring 6 to 6.5 cm. A cerclage-type suture is added on the tibial side of the 4-stranded semitendinosus construct to increase the stiffness of the graft. At least 10 mm of the graft length inside the femoral tunnel and 15 mm inside the tibial tunnel are needed for graft healing. Flexible reamers should be used with the knee at 90 of flexion. The tibial cortex should be broken before impaction of the bone dowel harvesting tube. The bone dowel can be introduced back into the tibial tunnel either before or after tibial button fixation. Final tension should occur in full extension and after cycling the knee through its full range of motion. ACL, anterior cruciate ligament.
The graft length is measured both before and after tensioning. Femoral Tunnel Creation A standard lateral portal for arthroscopic visualization is created. The medial portal should be made at the medial edge of the patellar tendon at the joint line (Fig 2A). With the knee flexed at 90 and by use of a ruler through the anterolateral portal, the center of the ACL footprint (Fig 2B) is determined. An appropriate Precision Curved Offset Femoral Guide (Zimmer Biomet) is selected, according to the desired margin of corticocancellous bone at the posterior femur. This guide is introduced at the native ACL footprint through the medial portal (Fig 2C). To ensure optimal guide placement, an alignment rod may be inserted either
through the coronal hole or the trajectory hole in the collar of the guide. The alignment rod placed in the coronal hole should be parallel to the joint line. Alternatively, in the trajectory hole, the alignment rod indicates the exit of the flexible guidewire on the lateral femoral cortex (Fig 2D). Once the Precision Femoral Guide is in position, a flexible guidewire is drilled and advanced through the lateral femoral cortex, to exit the skin on the lateral thigh, until the black laser line on the flexible guidewire meets the femoral bone in the notch (Fig 2E). The length of the femoral tunnel is measured by sliding the Precision Depth Gauge (Zimmer Biomet) down the flexible guidewire, through the skin and subcutaneous tissue at the lateral thigh, until contacting the femoral cortical bone (Fig 2F). The Precision Curved Femoral Guide is removed, and a Precision Flexible
Fig 1. Graft preparation. (A) Both free ends of the semitendinosus are stitched. Two adjustable-length loop cortical button devices are used: ToggleLoc, for the femur, and ToggleLoc XL Inline, for the tibia. (B) The tendon graft is symmetrically folded over the tibial cortical button loop. (C) The doubled graft is passed through the femoral cortical button loop and is symmetrically folded again. (D) One free end strand of the graft passes through the tibial button loop; both free ends of the graft are tied together with 2 knots. (E) The same sutures are tied over the graft itself with 4 knots. (F) The 4-stranded graft is reinforced on the tibial side with cerclage-type suture and a buried-knot technique.
QUADRUPLE SEMITENDINOSUS GRAFT CONSTRUCT
Fig 2. Creation of femoral tunnel. (A) Standard medial and lateral portals for arthroscopic visualization are created. (B) By use of a ruler through the anterolateral portal, the length of the anterior cruciate ligament footprint is measured. (C) An appropriate Precision Curved Offset Femoral Guide is selected to reach the center of the femoral anterior cruciate ligament footprint. (D) The guide is introduced through the medial portal. Two alignment rods are inserted in the collar of the guide, one through the coronal hole parallel to the joint line and the other through the trajectory hole to indicate the exit of the flexible guidewire on the lateral femoral cortex. (E) A flexible guidewire is drilled and advanced through the lateral femoral cortex, to exit the skin on the lateral thigh, until the black laser line (arrow) on the flexible guidewire meets the femoral bone in the notch. (F) The length of the femoral tunnel is measured, with the Precision Depth Gauge through the skin until contacting the femoral cortical bone. (G) A Precision Flexible Reamer with the same diameter as the graft is drilled over the guidewire until the desired tunnel depth is reached. (H) A suture is pulled proximally on the flexible guidewire to place the relay suture into the joint space and through the femoral tunnel.
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Fig 3. Bone dowel harvesting and tibial tunnel creation. (A) A guidewire is drilled through the center of the native anterior cruciate ligament footprint. (B) The cortex at the distal end of the tibial tunnel is removed with a reamer. (C) A cannulated plunger is inserted over the K-wire (arrow). (D) The harvesting tube is impacted over the cannulated plunger and the K-wire to the subchondral bone. The harvesting tube is rotated to break the tip of the bone dowel from the subchondral bone, and the harvesting tube is removed from the tunnel.
Reamer (Zimmer Biomet) with the same diameter as the graft is drilled over the guidewire until the desired tunnel depth is reached (Fig 2G). Then, a 4.5-mm Precision Flexible Reamer is used to ream over the flexible guidewire, perforating the lateral cortex of the femur. The free ends of a No. 2 MaxBraid suture are threaded through the eyelet of the flexible guidewire
and pulled proximally on the flexible guidewire to place the relay suture into the joint space and through the femoral tunnel (Fig 2H). Bone Dowel Harvest and Tibial Tunnel Creation To create the tibial tunnel, a Director Tibial Guide (Zimmer Biomet) is set at 55 , and the guidewire is
Fig 4. Graft passage. (A) The distances on the graft construct are marked, including the length of the total femoral tunnel in the adjustable graft loop and the length of the graft inside the femoral tunnel, measuring from the femoral graft end. (B) The femoral adjustable graft loop is pulled into the femoral tunnel, through the tibial tunnel, until the mark on the graft loop reaches the tunnel aperture. Once the button flips, the femoral pull suture is tensioned to pull the graft up into the femoral tunnel.
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Fig 5. Bone dowel introduction. (A) The bone plug is compacted into the tibial tunnel. (B) Coronal oblique computed tomography scan of bone dowel inside tibial tunnel.
drilled through the center of the native ACL footprint (Fig 3A). Subsequently, the cortex at the distal end of the tibial tunnel is removed with a reamer (Fig 3B). Then, a cannulated plunger (Zimmer Biomet) is inserted over the K-wire (Fig 3C), and the harvesting tube (Zimmer Biomet) is impacted over the cannulated plunger and the K-wire to the subchondral bone (Fig 3D). The harvesting tube is rotated clockwise and counterclockwise to break the tip of the bone dowel from the subchondral bone, and the harvesting tube is removed from the tunnel. In the end, the tibial tunnel is reamed through the subchondral bone. Graft Passage The first distance that should be measured and marked on the graft construct is the length of the total femoral tunnel. This distance should be marked on the adjustable graft loop, measuring from the proximal tip of the cortical suspensory button, while the surgeon holds the button in a pre-flipped position (Fig 4A). The second distance that should be considered is the length of the graft inside the femoral tunnel, and it depends on the total length of the graft. A typical amount is between 15 and 20 mm. This distance is marked on the graft itself, measuring from the femoral graft end. Finally, the length of the graft inside the joint is marked, usually 25 to 30 mm. The femoral adjustable graft loop is pulled into the femoral tunnel, through the
tibial tunnel, until the mark on the graft loop reaches the tunnel aperture, under direct arthroscopic visualization, indicating that the button has exited the femoral cortex proximally and is ready to flip. Once the button flips, the graft is pulled back to ensure solid femoral fixation. Next, the femoral pull suture is tensioned to pull the graft up into the femoral tunnel (Fig 4B). Then, the bone dowel is compacted into the tibial tunnel (Fig 5). With the knee in full extension, the tibial tensioning sutures are pulled until the graft and the button are seated in the tibial tunnel and cortical tibial bone, respectively (Fig 6). The knee is cycled through its range of motion 30 times, followed by re-tensioning by pulling the tibial sutures by hand in full extension.
Discussion The semitendinosus and gracilis (hamstring) tendons have been gaining popularity for use as ACL grafts because they have less morbidity and fewer complications than those seen with harvesting of patellar tendon graft. However, using hamstring tendons can decrease the strength of the internal tibial rotation of the operated limb when compared with the contralateral limb, and this weakness in internal rotation may contribute to deficits in athletic performance.2 With our technique, the gracilis is spared, thereby potentially reducing the internal rotation weakness. In addition, in the presented technique, even though only the semitendinosus
Fig 6. Tibial fixation. (A) The tibial tensioning sutures are pulled until the button is seated outside the tibial tunnel. (B) Three-dimensional computed tomography scan of ToggleLoc XL Inline in tibia after fixation.
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tendon is used, the quadruple construct is almost always larger in size than the standard quadruple semitendinosus and gracilis graft. A drawback with the quadruple semitendinosus is that, because the total length of the graft construct is shorter than the standard quadruple semitendinosus and gracilis graft, less graft is available to put inside the tunnels. Nonetheless, studies have shown that 10 to 15 mm and 15 to 20 mm of the graft length inside the femoral and tibial tunnels, respectively, are sufficient for healing of the graft.3,4 Classically, an interference biodegradable screw is used for tibial fixation. Certain problems, such as screw breakage, tunnel enlargement, allergic or foreign-body reactions, cyst or abscess formation, and delayed migration, have been reported with this type of fixation.5-8 Another issue with the interference screw is lower stiffness, with a risk of graft slippage.9 In our technique, fixation with a cortical button is used instead, which is a highly stiff and resistant fixation device,10 avoiding many of the problems ascribed to the interference biodegradable screw. Recently, Lubowitz et al.11,12 developed a new minimally invasive procedure for arthroscopic ACL reconstruction called the “all-inside technique.” The goal of the all-inside method is to minimize surgical trauma by drilling incomplete tibial and femoral tunnels and preserving the external cortex for fixation. Our technique requires a full tibial tunnel, but the tunnel is filled at the end of the operation with a bone dowel, keeping the bone stock intact.13 Our technique is simpler and easier than the all-inside technique butdin our opiniondwith the same benefits.14 The main limitation of this technique is that it is still unknown whether the tibial bone plug is fully integrated or becomes partially or even completely resorbed, thereby impairing its ability to restore the bone stock. However, it is known that a bone plug can prevent the enlargement of the tibial tunnel.13 In summary, this technique is safe, with a short learning curve; preserves the gracilis; saves bone; and increases the stiffness and resistance of the tibial fixation.
References 1. Brandsson S, Faxén E, Eriksson BI, Swärd L, Lundin O, Karlsson J. Reconstruction of the anterior cruciate ligament: Comparison of outside-in and all-inside techniques. Br J Sports Med 1999;33:42-45.
2. Viola RW, Sterett WI, Newfield D, Steadman JR, Torry MR. Internal and external tibial rotation strength after anterior cruciate ligament reconstruction using ipsilateral semitendinosus and gracilis tendon autografts. Am J Sports Med 2000;28:552-555. 3. Yamazaki S, Yasuda K, Tomita F, Minami A, Tohyama H. The effect of intraosseous graft length on tendon-bone healing in anterior cruciate ligament reconstruction using flexor tendon. Knee Surg Sports Traumatol Arthrosc 2006;14:1086-1093. 4. Zantop T, Ferretti M, Bell KM, Brucker PU, Gilbertson L, Fu FH. Effect of tunnel-graft length on the biomechanics of anterior cruciate ligament-reconstructed knees: Intraarticular study in a goat model. Am J Sports Med 2008;36:2158-2166. 5. Bostman O, Hirvensalo E, Makinen J, Rokkanen P. Foreign-body reactions to fracture fixation implants of biodegradable synthetic polymers. J Bone Joint Surg Br 1990;72:592-596. 6. Friden T, Rydholm U. Severe aseptic synovitis of the knee after biodegradable internal fixation. A case report. Acta Orthop Scand 1992;63:94-97. 7. Konan S, Haddad FS. A clinical review of bioabsorbable interference screws and their adverse effects in anterior cruciate ligament reconstruction surgery. Knee 1996;16: 6-13. 8. Weiler A, Helling HJ, Kirch U, Zirbes TK, Rehm KE. Foreign-body reaction and the course of osteolysis after polyglycolide implants for fracture fixation: Experimental study in sheep. J Bone Joint Surg Br 1996;78:369-376. 9. Magen HE, Howell SM, Hull ML. Structural properties of six tibial fixation methods for anterior cruciate ligament soft tissue grafts. Am J Sports Med 1999;27:35-43. 10. Petre BM, Smith SD, Jansson KS, et al. Femoral cortical suspension devices for soft tissue anterior cruciate ligament reconstruction: A comparative biomechanical study. Am J Sports Med 2013;41:416-422. 11. Lubowitz JH. No-tunnel anterior cruciate ligament reconstruction: The transtibial all-inside technique. Arthroscopy 2006;22:900.e1-900.e11. 12. Lubowitz J, Amhad CA, Anderson K. All-inside anterior cruciate ligament graft-link technique: Secondgeneration, no-incision anterior cruciate ligament reconstruction. Arthroscopy 2011;27:717-727. 13. Silva A, Sampaio R, Pinto E. ACL reconstruction: Effect of bone dowel on tibial tunnel enlargement. Knee 2013;20: 203-207. 14. Lubowitz JH, Schwartzberg R, Smith P. Randomized controlled trial comparing all-inside anterior cruciate ligament reconstruction technique with anterior cruciate ligament reconstruction with a full tibial tunnel. Arthroscopy 2013;29:1195-1200.
Abstract: Surgical techniques for anterior cruciate ligament reconstruction are evolving, becoming less invasive, with fewer and smaller incisions, preservation of knee bone stock and tendons at the donor site, and better graft positioning and fixation. We describe an anterior cruciate ligament reconstruction technique that aims to preserve bone stock and spares the gracilis. The semitendinosus graft construct is prepared in a quadruple way and fixed with a cortical button in both tunnels, with increased stiffness and resistance of the graft construct. The tibial tunnel is filled at the end of the operation with a bone dowel, keeping the bone stock intact. This technique is safe, with a short learning curve; preserves the gracilis; saves bone; and increases the stiffness and resistance of the tibial fixation.
A
rthroscopic anterior cruciate ligament (ACL) reconstruction is a common procedure. Surgical techniques are evolving, becoming less invasive, with fewer and smaller incisions, preservation of knee bone stock and tendons at the donor site, and better graft positioning and fixation.1 We describe a new ACL reconstruction technique that aims to preserve bone stock and uses only the semitendinosus tendon for graft preparation. The quadruple semitendinosus graft construct is prepared in a novel way and fixed with a new cortical suspensory button in the tibial tunnel, with increased stiffness and resistance of the graft construct (Video 1, Table 1).
Surgical Technique Patient Positioning The patient is placed in the supine position, with a post to assist with achieving a valgus moment, as well as a foot and thigh holder to hold the leg at 90 of flexion. From the Orthopedics Department, Hospital Militar D. Pedro V (A.S.); and Hospital Lusiadas Porto (R.S.), Porto, Portugal. The authors report the following potential conflict of interest or source of funding: A.S. receives support from Biomet. Received May 9, 2015; accepted July 31, 2015. Address correspondence to Alcindo Silva, M.D., Orthopedics Department, Hospital Militar D. Pedro V, Avenida da Boavista, 4050-113 Porto, Portugal. E-mail: [email protected] Ó 2016 by the Arthroscopy Association of North America 2212-6287/15435/$36.00 http://dx.doi.org/10.1016/j.eats.2015.07.030
Graft Harvest The semitendinosus graft is harvested through a traditional approach with an oblique incision over the pes anserinus tendons. Graft Preparation Both free ends of the semitendinosus are stitched over a length of 20 mm, using No. 2 ExpressBraid suture (Zimmer Biomet, Warsaw, IN). Two adjustable-length loop cortical button devices are used: ToggleLoc (Zimmer Biomet), for the femur, and ToggleLoc XL Inline (Zimmer Biomet), for the tibia (Fig 1A). The tendon graft is symmetrically folded over the tibial cortical button loop (Fig 1B), and the doubled graft is passed through the femoral cortical button loop and is symmetrically folded again (Fig 1C). One free end strand of the graft passes through the tibial button loop, and both free ends of the graft are tied together (Fig 1D). Then, the same sutures are tied over the graft itself with 4 knots (Fig 1E). Finally, the graft construct is placed on the graft tensioning table (Zimmer Biomet), and the 4-stranded graft is reinforced on the tibial side with No. 2 ExpressBraid cerclage-type suture. To achieve this, a buried-knot technique is used, starting from the inside of the graft and stitching outward, through the second, third, and fourth graft limbs. The suture is then wrapped around the graft and stitched back through the first graft limb. The suture is tied with 3 manual knots (Fig 1F). Pre-tensioning of the graft construct at 300 N is applied for 2 minutes in the graft station.
Arthroscopy Techniques, Vol 4, No 6 (December), 2015: pp e801-e806
e801
e802
A. SILVA AND R. SAMPAIO
Table 1. Key Points for ACL Reconstruction Technique Only the semitendinosus is harvested, with a length of at least 24 cm, to obtain a quadruple graft construct measuring 6 to 6.5 cm. A cerclage-type suture is added on the tibial side of the 4-stranded semitendinosus construct to increase the stiffness of the graft. At least 10 mm of the graft length inside the femoral tunnel and 15 mm inside the tibial tunnel are needed for graft healing. Flexible reamers should be used with the knee at 90 of flexion. The tibial cortex should be broken before impaction of the bone dowel harvesting tube. The bone dowel can be introduced back into the tibial tunnel either before or after tibial button fixation. Final tension should occur in full extension and after cycling the knee through its full range of motion. ACL, anterior cruciate ligament.
The graft length is measured both before and after tensioning. Femoral Tunnel Creation A standard lateral portal for arthroscopic visualization is created. The medial portal should be made at the medial edge of the patellar tendon at the joint line (Fig 2A). With the knee flexed at 90 and by use of a ruler through the anterolateral portal, the center of the ACL footprint (Fig 2B) is determined. An appropriate Precision Curved Offset Femoral Guide (Zimmer Biomet) is selected, according to the desired margin of corticocancellous bone at the posterior femur. This guide is introduced at the native ACL footprint through the medial portal (Fig 2C). To ensure optimal guide placement, an alignment rod may be inserted either
through the coronal hole or the trajectory hole in the collar of the guide. The alignment rod placed in the coronal hole should be parallel to the joint line. Alternatively, in the trajectory hole, the alignment rod indicates the exit of the flexible guidewire on the lateral femoral cortex (Fig 2D). Once the Precision Femoral Guide is in position, a flexible guidewire is drilled and advanced through the lateral femoral cortex, to exit the skin on the lateral thigh, until the black laser line on the flexible guidewire meets the femoral bone in the notch (Fig 2E). The length of the femoral tunnel is measured by sliding the Precision Depth Gauge (Zimmer Biomet) down the flexible guidewire, through the skin and subcutaneous tissue at the lateral thigh, until contacting the femoral cortical bone (Fig 2F). The Precision Curved Femoral Guide is removed, and a Precision Flexible
Fig 1. Graft preparation. (A) Both free ends of the semitendinosus are stitched. Two adjustable-length loop cortical button devices are used: ToggleLoc, for the femur, and ToggleLoc XL Inline, for the tibia. (B) The tendon graft is symmetrically folded over the tibial cortical button loop. (C) The doubled graft is passed through the femoral cortical button loop and is symmetrically folded again. (D) One free end strand of the graft passes through the tibial button loop; both free ends of the graft are tied together with 2 knots. (E) The same sutures are tied over the graft itself with 4 knots. (F) The 4-stranded graft is reinforced on the tibial side with cerclage-type suture and a buried-knot technique.
QUADRUPLE SEMITENDINOSUS GRAFT CONSTRUCT
Fig 2. Creation of femoral tunnel. (A) Standard medial and lateral portals for arthroscopic visualization are created. (B) By use of a ruler through the anterolateral portal, the length of the anterior cruciate ligament footprint is measured. (C) An appropriate Precision Curved Offset Femoral Guide is selected to reach the center of the femoral anterior cruciate ligament footprint. (D) The guide is introduced through the medial portal. Two alignment rods are inserted in the collar of the guide, one through the coronal hole parallel to the joint line and the other through the trajectory hole to indicate the exit of the flexible guidewire on the lateral femoral cortex. (E) A flexible guidewire is drilled and advanced through the lateral femoral cortex, to exit the skin on the lateral thigh, until the black laser line (arrow) on the flexible guidewire meets the femoral bone in the notch. (F) The length of the femoral tunnel is measured, with the Precision Depth Gauge through the skin until contacting the femoral cortical bone. (G) A Precision Flexible Reamer with the same diameter as the graft is drilled over the guidewire until the desired tunnel depth is reached. (H) A suture is pulled proximally on the flexible guidewire to place the relay suture into the joint space and through the femoral tunnel.
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Fig 3. Bone dowel harvesting and tibial tunnel creation. (A) A guidewire is drilled through the center of the native anterior cruciate ligament footprint. (B) The cortex at the distal end of the tibial tunnel is removed with a reamer. (C) A cannulated plunger is inserted over the K-wire (arrow). (D) The harvesting tube is impacted over the cannulated plunger and the K-wire to the subchondral bone. The harvesting tube is rotated to break the tip of the bone dowel from the subchondral bone, and the harvesting tube is removed from the tunnel.
Reamer (Zimmer Biomet) with the same diameter as the graft is drilled over the guidewire until the desired tunnel depth is reached (Fig 2G). Then, a 4.5-mm Precision Flexible Reamer is used to ream over the flexible guidewire, perforating the lateral cortex of the femur. The free ends of a No. 2 MaxBraid suture are threaded through the eyelet of the flexible guidewire
and pulled proximally on the flexible guidewire to place the relay suture into the joint space and through the femoral tunnel (Fig 2H). Bone Dowel Harvest and Tibial Tunnel Creation To create the tibial tunnel, a Director Tibial Guide (Zimmer Biomet) is set at 55 , and the guidewire is
Fig 4. Graft passage. (A) The distances on the graft construct are marked, including the length of the total femoral tunnel in the adjustable graft loop and the length of the graft inside the femoral tunnel, measuring from the femoral graft end. (B) The femoral adjustable graft loop is pulled into the femoral tunnel, through the tibial tunnel, until the mark on the graft loop reaches the tunnel aperture. Once the button flips, the femoral pull suture is tensioned to pull the graft up into the femoral tunnel.
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Fig 5. Bone dowel introduction. (A) The bone plug is compacted into the tibial tunnel. (B) Coronal oblique computed tomography scan of bone dowel inside tibial tunnel.
drilled through the center of the native ACL footprint (Fig 3A). Subsequently, the cortex at the distal end of the tibial tunnel is removed with a reamer (Fig 3B). Then, a cannulated plunger (Zimmer Biomet) is inserted over the K-wire (Fig 3C), and the harvesting tube (Zimmer Biomet) is impacted over the cannulated plunger and the K-wire to the subchondral bone (Fig 3D). The harvesting tube is rotated clockwise and counterclockwise to break the tip of the bone dowel from the subchondral bone, and the harvesting tube is removed from the tunnel. In the end, the tibial tunnel is reamed through the subchondral bone. Graft Passage The first distance that should be measured and marked on the graft construct is the length of the total femoral tunnel. This distance should be marked on the adjustable graft loop, measuring from the proximal tip of the cortical suspensory button, while the surgeon holds the button in a pre-flipped position (Fig 4A). The second distance that should be considered is the length of the graft inside the femoral tunnel, and it depends on the total length of the graft. A typical amount is between 15 and 20 mm. This distance is marked on the graft itself, measuring from the femoral graft end. Finally, the length of the graft inside the joint is marked, usually 25 to 30 mm. The femoral adjustable graft loop is pulled into the femoral tunnel, through the
tibial tunnel, until the mark on the graft loop reaches the tunnel aperture, under direct arthroscopic visualization, indicating that the button has exited the femoral cortex proximally and is ready to flip. Once the button flips, the graft is pulled back to ensure solid femoral fixation. Next, the femoral pull suture is tensioned to pull the graft up into the femoral tunnel (Fig 4B). Then, the bone dowel is compacted into the tibial tunnel (Fig 5). With the knee in full extension, the tibial tensioning sutures are pulled until the graft and the button are seated in the tibial tunnel and cortical tibial bone, respectively (Fig 6). The knee is cycled through its range of motion 30 times, followed by re-tensioning by pulling the tibial sutures by hand in full extension.
Discussion The semitendinosus and gracilis (hamstring) tendons have been gaining popularity for use as ACL grafts because they have less morbidity and fewer complications than those seen with harvesting of patellar tendon graft. However, using hamstring tendons can decrease the strength of the internal tibial rotation of the operated limb when compared with the contralateral limb, and this weakness in internal rotation may contribute to deficits in athletic performance.2 With our technique, the gracilis is spared, thereby potentially reducing the internal rotation weakness. In addition, in the presented technique, even though only the semitendinosus
Fig 6. Tibial fixation. (A) The tibial tensioning sutures are pulled until the button is seated outside the tibial tunnel. (B) Three-dimensional computed tomography scan of ToggleLoc XL Inline in tibia after fixation.
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tendon is used, the quadruple construct is almost always larger in size than the standard quadruple semitendinosus and gracilis graft. A drawback with the quadruple semitendinosus is that, because the total length of the graft construct is shorter than the standard quadruple semitendinosus and gracilis graft, less graft is available to put inside the tunnels. Nonetheless, studies have shown that 10 to 15 mm and 15 to 20 mm of the graft length inside the femoral and tibial tunnels, respectively, are sufficient for healing of the graft.3,4 Classically, an interference biodegradable screw is used for tibial fixation. Certain problems, such as screw breakage, tunnel enlargement, allergic or foreign-body reactions, cyst or abscess formation, and delayed migration, have been reported with this type of fixation.5-8 Another issue with the interference screw is lower stiffness, with a risk of graft slippage.9 In our technique, fixation with a cortical button is used instead, which is a highly stiff and resistant fixation device,10 avoiding many of the problems ascribed to the interference biodegradable screw. Recently, Lubowitz et al.11,12 developed a new minimally invasive procedure for arthroscopic ACL reconstruction called the “all-inside technique.” The goal of the all-inside method is to minimize surgical trauma by drilling incomplete tibial and femoral tunnels and preserving the external cortex for fixation. Our technique requires a full tibial tunnel, but the tunnel is filled at the end of the operation with a bone dowel, keeping the bone stock intact.13 Our technique is simpler and easier than the all-inside technique butdin our opiniondwith the same benefits.14 The main limitation of this technique is that it is still unknown whether the tibial bone plug is fully integrated or becomes partially or even completely resorbed, thereby impairing its ability to restore the bone stock. However, it is known that a bone plug can prevent the enlargement of the tibial tunnel.13 In summary, this technique is safe, with a short learning curve; preserves the gracilis; saves bone; and increases the stiffness and resistance of the tibial fixation.
References 1. Brandsson S, Faxén E, Eriksson BI, Swärd L, Lundin O, Karlsson J. Reconstruction of the anterior cruciate ligament: Comparison of outside-in and all-inside techniques. Br J Sports Med 1999;33:42-45.
2. Viola RW, Sterett WI, Newfield D, Steadman JR, Torry MR. Internal and external tibial rotation strength after anterior cruciate ligament reconstruction using ipsilateral semitendinosus and gracilis tendon autografts. Am J Sports Med 2000;28:552-555. 3. Yamazaki S, Yasuda K, Tomita F, Minami A, Tohyama H. The effect of intraosseous graft length on tendon-bone healing in anterior cruciate ligament reconstruction using flexor tendon. Knee Surg Sports Traumatol Arthrosc 2006;14:1086-1093. 4. Zantop T, Ferretti M, Bell KM, Brucker PU, Gilbertson L, Fu FH. Effect of tunnel-graft length on the biomechanics of anterior cruciate ligament-reconstructed knees: Intraarticular study in a goat model. Am J Sports Med 2008;36:2158-2166. 5. Bostman O, Hirvensalo E, Makinen J, Rokkanen P. Foreign-body reactions to fracture fixation implants of biodegradable synthetic polymers. J Bone Joint Surg Br 1990;72:592-596. 6. Friden T, Rydholm U. Severe aseptic synovitis of the knee after biodegradable internal fixation. A case report. Acta Orthop Scand 1992;63:94-97. 7. Konan S, Haddad FS. A clinical review of bioabsorbable interference screws and their adverse effects in anterior cruciate ligament reconstruction surgery. Knee 1996;16: 6-13. 8. Weiler A, Helling HJ, Kirch U, Zirbes TK, Rehm KE. Foreign-body reaction and the course of osteolysis after polyglycolide implants for fracture fixation: Experimental study in sheep. J Bone Joint Surg Br 1996;78:369-376. 9. Magen HE, Howell SM, Hull ML. Structural properties of six tibial fixation methods for anterior cruciate ligament soft tissue grafts. Am J Sports Med 1999;27:35-43. 10. Petre BM, Smith SD, Jansson KS, et al. Femoral cortical suspension devices for soft tissue anterior cruciate ligament reconstruction: A comparative biomechanical study. Am J Sports Med 2013;41:416-422. 11. Lubowitz JH. No-tunnel anterior cruciate ligament reconstruction: The transtibial all-inside technique. Arthroscopy 2006;22:900.e1-900.e11. 12. Lubowitz J, Amhad CA, Anderson K. All-inside anterior cruciate ligament graft-link technique: Secondgeneration, no-incision anterior cruciate ligament reconstruction. Arthroscopy 2011;27:717-727. 13. Silva A, Sampaio R, Pinto E. ACL reconstruction: Effect of bone dowel on tibial tunnel enlargement. Knee 2013;20: 203-207. 14. Lubowitz JH, Schwartzberg R, Smith P. Randomized controlled trial comparing all-inside anterior cruciate ligament reconstruction technique with anterior cruciate ligament reconstruction with a full tibial tunnel. Arthroscopy 2013;29:1195-1200.