Authors: Griffin R. Rechter, Adam J. Tagliero, Lindsay Barrera, Mario A. Hevesi, Kelechi R. Okoroha, Aaron J. Krych, Bruce A. Levy
Categories: Technical Note
Source: Arthroscopy Techniques
Authors: Griffin R. Rechter, Adam J. Tagliero, Lindsay Barrera, Mario A. Hevesi, Kelechi R. Okoroha, Aaron J. Krych, Bruce A. Levy
Anterior cruciate ligament reconstruction (ACLR) using bone–patellar tendon–bone autograft remains one of the most common autografts used, and there is significant evidence to support its title as the “gold standard.” There are nuances and technical challenges associated with every step of an ACLR, which always leave room for improvement. The purpose of this Technical Note is to provide reproducible, technical pearls where errors are commonly encountered during ACLR. In this article, we detail 10 technical pearls that surgeons should consider to enhance operative workflow and optimize success during ACLR with a bone–patellar tendon–bone autograft.
While anterior cruciate ligament (ACL) reconstruction is one of the most common surgeries in orthopaedic sports medicine, ACL graft choice remains a subject of debate. Among the graft options available for ACL reconstruction (ACLR), the bone–patellar tendon–bone (BPTB) autograft remains the “gold standard,” with significant evidence to support its use.1, 2, 3, 4 The BPTB autograft provides predictable bone-to-bone healing, relatively low rates of graft elongation, consistent graft size during harvesting, and low retear rates.5, 6, 7 The downside of the ACL BPTB graft is the risk of anterior knee pain, patella fractures, and patellar tendon tears.^6^^,^8, 9, 10 The purpose of this article is to provide a detailed description of 10 reproducible technical pearls for surgeons to consider to optimize their operative technique during an ACL reconstruction with a BPTB autograft.
A video presenting this technique is provided (Video 1).
The central third of the patellar tendon (PT) is considered the gold-standard location for BPTB harvesting, because it has shown an ability to reconstitute itself, and eccentric harvesting risks PT rupture.^5^^,^^11^^,^^12^ A technical pearl to identify the central third is facilitated by the use of Metzenbaum scissors to aid with PT visualization. The scissors are inserted posterior to the PT and expanded to augment the surface area, achieving a flat surface for visualization. A ruler is then used to measure the width of the PT, enabling identification of the tendinous center to separate the PT into thirds (Fig 1).Fig 1A left knee model in 90 degrees of flexion showing Metzenbaum surgical scissors inserted posterior to the PT, facilitating visualization of the entire PT width. The 2 dots divide the tendon into thirds to identify the tendinous center for harvesting the central third of the PT. (PT, patellar tendon.)
Meticulous closure of the graft harvest site is imperative to decrease kneeling pain postoperatively and prevent synovial fistula formation.^13^ A technical pearl for reliable PT closure involves placing the knee into 90° of flexion, which assists in preventing patella baja and contracture development. Next, a 0-Vicryl suture (Ethicon) is used to close the PT, with a suture pass depth of half of the total depth of the tendon (Fig 2). Subsequently, the knee is placed into 30° of flexion, and a running 3-0 Monocryl (Ethicon) suture is used to close the paratenon layer (Fig 3). The authors prefer to “lock” the running suture. The subcutaneous skin layer is closed with an interrupted 3-0 Vicryl, followed by a running 4-0 Monocryl in the subcuticular layer to obtain a watertight seal.Fig 2A left knee model, in 90 degrees of flexion, showing final closure of the PT with 3 interrupted 0-Vicryl (Ethicon) sutures in a figure-of-8 fashion. (PT, patellar tendon.)Fig 3A left knee model, in 90 degrees of flexion, showing meticulous closure of the paratenon layer with a 3-0 Monocryl (Ethicon) suture in a running fashion.
A technical pearl, in the event of a bone-block mismatch, is to place a safety stitch on the tibial end of the graft to thwart any complication during passing of the graft through the tibial tunnel. On the tibial side of the graft, at the level of the bone–patellar tendon interface, a No. 2 FiberWire suture (Arthrex) is placed slightly posterior in the graft. Using the same suture, a second pass of the suture is made ∼0.5 cm more proximal in the graft, at the same level of the first suture. The suture limbs are then pulled so that the nonlocked loop rests flush at the bone-tendon interface, and a loop of suture is then tied around the graft (Fig 4).Fig 4Image of the ACL BPTB graft with placement of the first pass of the No. 2 FiberWire safety suture (Arthrex) on the tibial side of the graft at the level of the bone–patellar tendon interface. (ACL, anterior cruciate ligament; BPTB, bone–patellar tendon–bone.)
Bone tunnel–graft mismatch is a difficult intraoperative complication to resolve, even for ACLR experts.^14^ Mismatch will lead to the tibial bone plug protruding out of the tunnel, hindering bone-to-bone fixation, and can occur in up to 26% of ACLRs. While techniques are described on how to prevent mismatch, there is a paucity of techniques detailing how to navigate out of this situation.^15^^,^^16^ This technical pearl becomes relevant once the femoral bone block is advanced deep into the femoral socket and mismatch is apparent. One can remove the excess bone protruding from the tunnel with the sutures placed through the bone block, and pulling on the safety stitch, graft control is maintained. This allows interference fixation, akin to a soft tissue graft, and back-up fixation with the safety stitch sutures tied over a post. When surveyed, ACLR surgeons described over 15 different techniques for managing tunnel mismatch, indicating a poor consensus on how to manage this complication.^15^
Inadequate visualization of the tibial and femoral footprints leads to nonanatomic graft placement and risks iatrogenic injury to the anterior horn of the lateral meniscus (AHLM) and posterior horn of the lateral meniscus (PHLM).17, 18, 19 The ACL lies ∼7.5 mm medial to the AHLM, underscoring the need to understand its anatomic relationships.^19^^,^^20^ To minimize iatrogenic meniscal injury, a technical pearl is to ensure removal of the anterior fat pad to provide an unobstructed view of the AHLM and PHLM. When necessary, removal of the intermensical ligament can facilitate tibial footprint identification, and no known clinical data show adverse effects of its removal.^21^ During femoral notch preparation, keep the shaver superior to the PHLM, where it is safe to debride on bone (Fig 5). Lastly, use both the anterolateral and anteromedial (AM) portals to visualize the proximal and posterior aspects of the femoral notch for anatomic socket placement.Fig 5Arthroscopic view of a left knee from the AL portal with the shaver in the AM portal preparing the femoral notch. Importantly, the shaver is always superior to the level of the posterior horn of the lateral meniscus. (AL, anterolateral; AM, anteromedial; LFC, lateral femoral condyle.)
Two common errors during ACLR are graft impingement and nonanatomic femoral socket placement. A technical pearl to avoid graft impingement involves the use of a straight curette of similar width to one’s graft. The curette is placed into the notch, acting as a ruler, confirming sufficient area to pass the graft and prevent overstuffing (Fig 6). If the curette impinges, then a notchplasty can be performed. This is critical to avoid graft impingement, which may lead to a cyclops lesion or graft failure.^22^^,^^23^Fig 6Arthroscopic view of a left knee from the anterolateral portal showing the use of a curette, 10 mm in width, to verify sufficient room for passage of the graft into the femoral tunnel (assuming a 10-mm-wide graft).
The advantage of the low AM portal drilling is the independent creation of the femoral socket, which is shown to be superior to the transtibial technique.^24^^,^^25^ Small deviations from the anatomic footprint may result in unsatisfactory outcomes.^26^^,^^27^ The disadvantage of the low AM portal drilling technique is surgeon disorientation when the knee is placed in a hyperflexed position. To counter this, place the arthroscope into the AM portal, confirming debridement of the femoral notch and visualization up to the posterior aspect of the lateral femoral condyle (LFC) (Fig 7). A 45° microfracture awl is advanced (in the low AM portal) into the femoral notch and stopped 5 mm from the posterior border of the LFC and then inserted 2 mm into the LFC (Fig 8). The hole position is confirmed through the AM portal, and its relationship to the posterior border of the LFC is noted (Fig 9). The femoral guide and 2.4-mm guide pin are inserted, and the knee is placed into hyperflexion. This *technical pearl—*creating a small mark with the awl prior to tunnel drilling—provides a target for positioning of the guide pin. The awl should be inserted into the center of the ACL femoral footprint, approximately 50% of the proximal-to-distal distance of the lateral femoral notch.^28^^,^^29^ Drilling of the tunnel, followed by reaming, ensues.Fig 7Arthroscopic view of a left knee from the AM portal showing sufficient debridement, enabling visualization of the posterior aspect of the femoral notch. (AM, anteromedial; L, lateral; LFC, medial femoral condyle; M, medial.)Fig 8Arthroscopic view of a left knee through the anterolateral portal showing the microfracture awl in the AM portal, with the knee in 90° of flexion. The awl is used to create a pilot hole at the anatomic footprint of the anterior cruciate ligament on the lateral femoral wall. (AM, anteromedial; LFC, lateral femoral condyle.)Fig 9Arthroscopic view of a left knee from the AM portal showing the product of the microfracture awl pilot hole in the anatomic footprint of the anterior cruciate ligament on the LFC. (AM, anteromedial; LFC, lateral femoral condyle.)
Another cause of graft-tunnel mismatch is failure to achieve adequate tibial tunnel length.^30^ A thorough debridement of the fat pad enables visualization of the tibial surface. The AHLM is identified along with the anterior aspect of the ACL. A radiofrequency ablation device is inserted, and a mark in between these two landmarks is created for the future site of the tibial tunnel (Fig 10).Fig 10Arthroscopic view of a left knee from the AL portal identifying the AHLM and the anterior aspect of the anterior cruciate ligament. The RFA device is placed between the 2 landmarks, in the anatomic tibial anterior cruciate ligament footprint, as the future site of the tibial tunnel guide. (AHLM, anterior horn of lateral meniscus; AL, anterolateral; RFA, radiofrequency ablation.)
A technical pearl, to avoid insufficient tibial tunnel length, is to set the tibial guide to 40 mm. The tibial drill guide (Arthrex) is inserted, and the tip of the guide is placed in the center of the ACL tibial footprint and slightly posterior to the AHLM. At least 40 mm must be present on the tibial drill sleeve (Arthrex) for adequate tibial tunnel length (Fig 11). Oftentimes, slight extension of the knee is necessary to obtain the desired 40-mm length.Fig 11Image of the tibial drill guide (Arthrex) and showing that at least 40 mm of length on the ratched drill sleeve is needed.
After the guide pin is inserted, we recommend using a barrel reamer approximately 2 mm smaller than the graft size for a 2-staged reaming process (i.e., for a 9-mm graft, use a 7-mm reamer). It is not uncommon for the pin to slightly deviate from the optimal tibial tunnel position during insertion. If the pin misses the desired center of the ACL footprint after reaming, a technical pearl is to eccentrically ream to achieve an anatomic position. This is accomplished by using a hemostat to grasp the pin, and then the reamer is placed over the guide pin. The hemostat can “joystick” the pin into the anatomic footprint center (Fig 12). Subsequently, reaming with a barrel reamer equivalent to the diameter of the graft follows (i.e., for a 9-mm graft, use a 9-mm reamer). Too anterior of a tibial tunnel results in graft impingement on the intercondylar roof, whereas too posterior results in excessive verticality of the graft and decreased anterior translation resistance.31, 32, 33Fig 12(Left) Arthroscopic view of a left knee through the AL portal with the pin secured with a hemostat to allow for “joysticking” after the initial 7-mm barrel reamer is used. (Right) If there is deviation of the pin from the planned tunnel, eccentric reaming using this technique can easily correct any malpositioning. A second barrel reamer, matching the graft diameter, is used to ream eccentrically. (AL, anterolateral.)
Prior to passage of the graft, unobstructed access to the tibial tunnel is needed. At the proximal anteromedial tibial incision, a bovie or scalpel is used to ensure that the incision is carried down to bone with no soft tissue entrapment into the tunnel (Fig 13).Fig 13Image of a left knee in 90 degrees of flexion with a drilled tibial tunnel that has been completely freed of any soft tissue obstructing visualization and access into the tibial tunnel.
This technical pearl ensures that the graft should then glide smoothly through the tibial tunnel. Failure to adequately expose the tibial tunnel before graft passage can result in difficulty passing the graft, resulting in damage to the graft integrity and unnecessary additional operative time.
Once the graft is inside the joint, a technical pearl is to guide the graft’s femoral bone block into the tunnel, using a probe, for proper rotation. While advancing, placement of the probe into the bone block hole can rotate the graft, as it enters the tunnel, facilitating a seamless passage and correct orientation (Fig 14).^34^ To ensure the femoral side of the graft is secured, the cancellous bone is rotated and positioned anterolateral. Optimal osseous healing is achieved with press-fit fixation of the plug in the tunnel, which is achieved when the bone block is aligned with the femoral tunnel, and will be augmented with an interference screw.^35^Fig 14Arthroscopic view of a left knee from the AL portal of the graft being guided into the femoral tunnel. The probe, in the AM portal, can be used to rotate the graft into the appropriate position. (AL, anterolateral; AM, anteromedial.)
A small notch in the aperture of the anterolateral aspect of the femoral bone socket is created using a notching device. A nitinol wire is placed through the low AM portal and advanced into the notched area of the socket. A technical pearl is to pull the ACL graft into the femoral socket, but importantly, it should not be completely docked (Fig 15). Leaving the bone plug proud allows passage of the nitinol wire, so it is placed into the bone with a minimum of 20 mm. The wire must be affixed in the bone to prevent femoral screw rotation around the bone plug and displacing the bone plug and graft anteriorly (Fig 16). Once the wire is firmly in the bone, the graft is fully seated in the femoral socket, and the interference screw is advanced over the nitinol wire (Fig 17).Fig 15Arthroscopic view of a left knee from the AL portal showing incomplete seating of the femoral bone block in the femoral tunnel, which will facilitate easy placement of the nitinol wire. (AL, anterolateral.)Fig 16Intracapsular arthroscopic view of a left knee from the anterolateral portal showing the nitinol wire inserted in the notch superior to the femoral bone block to control rotation.Fig 17Arthroscopic view of a left knee from the AL portal while the interference screw is inserted anterior to the bone plug through the AM portal. (AL, anterolateral; AM, anteromedial.)
While ACLR with a BPTB autograft has well-documented outcomes, the procedure remains technically demanding, with several intraoperative pitfalls that can compromise graft function and fixation. This Technical Note highlights critical steps that can meaningfully impact outcomes and improve the execution of this operation. Graft-tunnel mismatch and ACL graft malpositioning remain 2 common causes of technical failure in ACLR. The described “pearls”—such as the safety stitch to address bone-tunnel graft mismatch and the use of an awl for precise femoral socket targeting—highlight the importance of anticipating surgical challenges before they arise and show reproducible solutions to address difficult intraoperative challenges (Table 1). Collectively, the described “pearls” provide a reproducible framework and workflow that minimize complications in ALCR with a BPTB autograft.Table 1Pearls & PtifallsPearlsPitfallsGraft visualizationUse Metzenbaum scissors to augment the patellar tendon surface area to properly identify the central third of the tendon.Avoid eccentric harvesting, which carries the risk of patellar tendon rupture.Harvest site closureClose the PT in 90° of flexion and obtain a watertight seal of the subcutaneous layer.Failing to close in 90° of flexion may cause patella baja and anterior kneeling pain. Poor closure risks synovial fistula formation.Bone plug securityUse of a safety suture maintains graft control and allows easy correction in the case of mismatch.Bone plug mismatch hinders bony healing and is difficult to correct in the absence of a safety suture.Tibial and femoral footprint visualizationExcellent exposure of the anatomic footprints is paramount; removal of the intermensical ligament is sometimes necessary for visualization.Poor visualization risks nonanatomic graft placement and iatrogenic meniscal injury.Precise femoral tunnel drillingMark the center of the anatomic footprint with a 45° awl before placing the guide pin.Nonanatomic femoral socket placement risks graft failure and cyclops lesion formation.Tibial tunnel positioningEnsure minimum of 40 mm available on the tibial drill guide; sometimes slight extension of knee is needed to obtain minimum length.Too short of a tibial tunnel leads to mismatch and poor graft fixation.Two-staged tibial tunnel reamingStart with a barrel reamer 2 mm smaller than one’s graft size to allow for “joysticking” of the pin to the anatomic tibial footprint before passing a barrel reamer equivalent to the final graft size.Too anterior of a tunnel will result in impingement, whereas too posterior of a tunnel leads to a vertical graft and reduced resistance to anterior translation.Unobstructed access to the tibial tunnelEnsure circumferential exposure and thorough debridement of the tibial tunnel before passing graft.Soft tissue entrapment within the tibial tunnel may damage the graft and hinders passage.Ensuring graft position during femoral tunnel passageUse of a probe allows the surgeon to guide the bone block into the femoral socket and ensure proper graft rotation into the tunnel.Poor orientation compromises tunnel fit and press-fit bone healing.Preventing screw-graft rotationPlacement of a nitinol wire in the femoral bone socket before passage of the graft prevents screw-graft rotation during graft passage.Failure to maintain rotational control of the graft while securing it with the interference screw risks graft rotation and displacement.PT, patellar tendon.
The authors declare the following financial interests/personal relationships which may be considered as potential competing A.J.T. is a consultant or advisor for Smith & Nephew and Endo Pharmaceuticals; has received travel reimbursement from Stryker Orthopaedics, Zimmer Biomet Holdings, Arthrex, and DePuy Synthes; and has received funding grants from Arthrex. M.A.H. is a consultant or advisor for DJO Surgical, Moximed, and Vericel; has received funding grants from Elsevier; and is a board member of the Journal of Cartilage and Joint Preservation. K.R.O. is a consultant or advisor for Smith & Nephew and Arthrex and is a board member of VJSM. A.J.K. is a consultant or advisor for Arthrex. B.A.L. is a consultant or advisor for Arthrex and Smith & Nephew, has equity or stocks with COVR, and is a board member of the Journal of Knee Surgery, Knee Surgery, Sports Traumatology, International Society for Knowledge for Surgeons on Arthroscopy and Arthroplasty, and Orthopedics Today. All other authors (G.R.R., L.B.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.