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Tibial Inlay Technique Using Hamstring Graft for Posterior Cruciate Ligament Reconstruction and Remnant Revision
Tibial Inlay Technique Using Hamstring Graft for Posterior Cruciate Ligament Reconstruction and Remnant Revision Wiroon Laupattarakasem, M.D., Manusak Boonard, M.D., Pat Laupattarakasem, M.D., and Weerachai Kosuwon, M.D.
Abstract: The posterior tibial inlay technique is currently accepted as a standard operation for the posterior cruciate ligamentedeficient knee. The classical technique requires a graft construct consisting of a bony part to be fitted into the posterior tibial socket. When an autogenous source is chosen, morbidity at the donor site generated by obtaining the graft with a bony part (e.g., boneepatellar tendonebone or quadriceps tendonebone) can be more serious than when obtaining the soft-tissue graft (e.g., hamstring). This study describes an alternative use of soft-tissue graft anchored in a bone socket at the posterior tibial margin by a transfixing cancellous screw. The graft is secured on top by a “bone washer” harvested from this bone socket to provide biological bone-tendon-bone healing. The posterior cruciate ligament remnant with integral fibers at the femur can have its tibial part revised, tensioned, and reattached concomitantly. This additional procedure is deemed to enhance joint stability and promote graft healing.
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urgery to restore posterior stability of the posterior cruciate ligament (PCL)edeficient knee is still inconclusive regarding the most reliable and least technically challenging approach.1,2 The arthroscopically assisted transtibial technique uses either a boneesoft tissue construct or a graft of soft tissue alone, whereas the classical open tibial inlay procedure requires a composite graft containing a bony part to be fixed into the posterior tibial socket. The inherent benefits of the inlay technique are its anatomic replacement and avoidance of the acute graft bending, or “killer turn,” that can cause graft laxity, as is commonly seen after the transtibial technique.3 However, in places lacking allogeneic graft or declining its use, harvesting autogenous tissues associated with a bony part (e.g., boneepatellar tendonebone or quadriceps tendonebone) usually can produce more serious donor-site morbidity than when obtaining only
soft tissues (e.g., semitendinosus and gracilis). Alternative use of soft-tissue graft for the tibial inlay technique will therefore extend choices of graft source and increase the flexibility of this approach. We apply the technique described as an “intraosseous anchorage of the soft-tissue graft”4 to our proposition. This technique essentially creates a bone block at the graft anchor site, where the soft-tissue graft is later laid into the resultant bony defect. The bone block, which has been predrilled for a lag screw, is then inserted in situ and functions as a washer compressing over the graft. When using this technique for PCL reconstruction, we often observe essential remnants that remain attached both to the femur and to the tibia. When indicated, this remnant is concomitantly revised and anchored with tension under the same bone washer, to augment joint stability and promote graft healing.
Surgical Techniques From the Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. The authors report that they have no conflicts of interest in the authorship and publication of this article. Received August 6, 2012; accepted September 14, 2012. Address correspondence to Wiroon Laupattarakasem, M.D., Department of Orthopaedics, Srinagarind Hospital Endoscopy Center, Faculty of Medicine, Khon Kaen University, 123 Mitraparp Road, Khon Kaen 40002, Thailand. E-mail: [email protected] Ó 2013 by the Arthroscopy Association of North America 2212-6287/12511/$36.00 http://dx.doi.org/10.1016/j.eats.2012.09.001
The surgery should be performed by a team of operating room personnel who have fully rehearsed changing the patient’s position throughout the course of the operation. General Setup We prefer placing the patient supine on the operating table that is equipped with 2 adjustable leg plates (Alphamaquet; Maquet, Rastatt, Germany) for later readjustment of the position. Arthroscopic procedures of the knee are conducted with the patient in this
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supine position, and the surgeon works by the side. A side post is installed just proximal to the ipsilateral hip joint to support the patient when the table is tilted side down. During the surgical approach to the popliteal area, the supporting leg plate for the operative limb is dropped down or uncoupled while the leg is transferred onto a small rolling work table with locking casters. The ipsilateral hip is abducted and fully externally rotated; the operating table is tilted side down to help open up the posteromedial aspect of the knee. The leg plate supporting the other limb is abducted so that the surgeon can sit between the 2 lower limbs (Fig 1). With this setup, the whole operating procedure can be accomplished without the need to re-scrub and turn the patient 180 upon alternating anterior and posterior approaches. A tourniquet is usually used during the operation if not clinically contraindicated. Graft Preparation If the diagnosis of the PCL deficiency is certain and autogenous soft-tissue grafts are required, semitendinosus and gracilis tendons from the same side are retrieved routinely (Video 1) using a closed tendon stripper (Smith & Nephew, Andover, MA). Otherwise, arthroscopic examination should be performed first to determine the general intra-articular pathology and consider the appropriate surgeries. The grafts can be prepared on a side table by the assistant while the surgeon is working on the knee. The preferred length of each tendon is 18 to 20 cm. The 2 tendons are paired by sewing the proximal end of 1 strand to the distal end of the other strand to create a double-strand graft of similar caliber at both ends. Two No. 2 Vicryl sutures (Ethicon, Somerville, NJ) are affixed at each end by use of running whipstitches. The tendons are doubled into a 9- to 10-cm-long quadrupled construct. The graft construct is then pre-sized and pre-tensioned using the standard devices (Graft Sizing Tubes and GraftMaster System; Smith & Nephew). Arthroscopic Femoral Tunnel Preparation We perform diagnostic arthroscopy using the standard anterolateral and anteromedial portals. Associated intra-articular pathology such as meniscal and cartilage lesions is primarily addressed. Redundant tissues are cleaned, and the anatomic PCL footprint at the medial femoral condyle is located. However, remnant fibers of the PCL and/or meniscofemoral ligament (MFL), if remaining integral at the femoral site, can be preserved.5 These fibers usually are attenuated and attach at the tibial intercondylar area somewhat anterior to the normal position after posterior tibial translation. Single-bundle or double-bundle reconstruction can be planned, although we currently prefer the former6 and emphasize replacing the anterolateral bundle.
Fig 1. Bird’s-eye view showing the scenario for patient setup during the open popliteal approach for the tibial inlay technique. The patient is placed supine on an operating table equipped with 2 modular leg plates. The leg plate supporting the operative knee is dropped down, and the leg is transferred onto a work table with the hip fully externally rotated, flexed, and abducted. The other leg plate is abducted to provide more room for the surgeon to sit between the 2 lower limbs. The operating table is side tilted to further open up the popliteal area.
The surgeon locates the outside-in femoral tunnel entry site through a small incision and medial subvastus dissection at about 1 to 2 cm proximal to the articular margin on the anteromedial aspect of the distal femoral metaphysis. By use of the PCL femoral aimer (Acufex Director; Smith & Nephew), the medial femoral tunnel conforming to the graft size is reamed into the anterolateral bundle footprint (at around the 11- or 1-o’clock position as appropriate). The surgeon should guard the remnant fibers away from the exiting reamer by the hoop tip of the aimer. The direction of the tunnel should be closely aligned with the PCL axis, and the aperture rim is beveled with a bone tunnel chamfering rasp (Smith & Nephew) to reduce graft-tunnel divergence and aperture impingement to the intra-articular part of the graft.7 A 1.0-mm-diameter wire-loop suture retriever is passed through the tunnel, lying medial to the anterior cruciate ligament and toward the posterior compartment. This preparation will significantly facilitate the passage of the graft from the posterior compartment in the next step. Open Posterior Approach If a tourniquet is being used, it is intermittently released and inflated again during this step while the patient’s position is readjusted, as mentioned earlier. The posterior knee compartment is approached through a posteromedial hockey-stick incision with its straight arm placed just lateral to the medial hamstring.8 The interval between the medial head of the gastrocnemius and the semimembranosus tendon is identified and
HAMSTRING TIBIAL INLAY TECHNIQUE
bluntly dissected to expose the posterior capsule. The tibial condyle is more eminent at its posteromedial aspect, which can increase the difficulty of the approach. The posterior tibial fovea where the normal PCL attaches is palpated. The surgeon opens the posterior capsule by incising along the lateral border of the medial femoral condyle, crossing the joint line and continuing distally medial to the fovea to adequately expose the posterior compartment. The tip of a Hohmann retractor can be hammered into the lateral part of the proximal tibia to help lever away the capsular flap for better exposure. The PCL footprint and redundant tissues are identified and cleaned. If the PCL/MFL remnant at the femur remains with significant thickness and continuity at the tibia, the structure usually has laxity when the posterior tibial translation is reduced. In this case, the surgeon should identify the anterior border of the remnant attachment and, using a small osteotome, peel the structure off from the tibial intercondylar area, together with a thin layer of cortex where it attaches. The surgeon repairs and augments the stump with 2 nonabsorbable sutures (Ethibond Excel 5; Ethicon), leaving suture tails for remnant tensioning and fixation during the next step (not shown in Video 1). Bone Washer Preparation First, the surgeon drills a 3.2-mm core hole for a 6.5-mm cancellous screw (Synthes, Oberdorf, Switzerland) within the PCL footprint at about 1 cm distal to the posterior tibial margin. The drill bit should be targeted toward the anterolateral aspect of the proximal tibia to minimize possible conflict with the future transtibial drill path aimed from the anteromedial aspect. The surgeon then measures the depth and pre-taps the hole for the cancellous screw thread. Using an osteotome or reciprocating saw as appropriate, he or she removes a piece of 7mm-thick unicortical bone block, about 15 20 mm in size, with the screw hole in the middle (Fig 2). A partially threaded cancellous screw is inserted into the bone block, which will now act as a bone washer. A commercial metal or spiked washer should be added to back up this bone washer. Graft Passage Using the wire-loop suture retriever previously placed in the posterior compartment, the surgeon pulls the affixing sutures leading the free graft ends past the compartment into the femoral tunnel. A strip of the umbilical tape temporarily appended to the graft loop helps in controlling the graft passage, as shown in Video 1. The surgeon slings the looped end over the cancellous screw shaft and in front of the bone washer. The screw shaft is now acting as a transfixing post of the graft (Fig 3). If the PCL/MFL remnant has been previously prepared, the posterior tibial sagging is primarily
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Fig 2. Outline for the harvest of the unicortical bone block from the footprint area of the PCL at the tibia. This material will subsequently function as the bone washer. The black dot represents the central drill hole for the cancellous screw.
reduced. The remnant is then pulled taut against either side of the screw shaft and anterior or posterior to the graft loop, according to the anatomy of the remnant bundle (Fig 4). The screw is inserted into the predrilled hole until the bone washer is seated in situ, sandwiching the graft (and the remnant with sutures) against the bony socket. Intentionally, the screw is only moderately fastened at this step. Graft Fixation at Femur The surgeon tightly pulls the graft ends now already located in the femoral tunnel. To ensure proper graft position in the joint, this is arthroscopically checked without fluid instillation (because the posterior capsule is still open). The knee is flexed and extended several times to lessen any slackened tissue. The proximal tibia is pulled anteriorly with the knee flexed at about 80 , and a bioabsorbable interference screw is inserted in an outside-in manner to secure the graft ends. The affixing sutures should be post-tied as a backup fixation. Wrapping Up Having fixed the graft ends posteriorly at the tibia and anteromedially at the femur, the posterior-drawer sign should now be negative with normal anteromedial tibial step off and the knee can be mobilized in full range. The surgeon should return to the posterior operative field again to drive the cancellous screw snugly home. If the PCL/MFL remnant is being fixed, the screw should be slightly loosened to pull the remnant tight before
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Fig 3. The hamstring graft bundles are slung over the cancellous screw shaft for the tibial inlay technique using this graft for PCL reconstruction. The affixed sutures leading the free ends of the graft have been introduced into the medial femoral tunnel from the posterior compartment. The bone washer will then be driven together with the commercial washer to compress on the transfixed hamstring graft against the bone socket bed.
driving the screw. This step will further tension the graft (and the remnant) being sandwiched between the bone washer and the bone socket bed. If desired, the affixing sutures to the remnant can be pulled out anteriorly through separate drill tracks parallel to the screw and post-tied at the tibia. The treatment algorithm is presented in the flow diagram (Fig 5). Advantages, indications, contraindications, tips and pearls, pitfalls and risks, key points, and limitations of the procedure are further described in Table 1. We recommend immediate correction of any associated posterolateral and/or posteromedial rotatory instability to warrant combined effects on stabilization of the posterior tibial translation.9 The surgeon should retain a vacuum drainage and meticulously repair the posterior capsule before closing
Fig 4. The peeled-off remnant fibers of the PCL and/or MFL with a thin layer of the attaching bone plate at the tibia are augmented with sutures. The remnant is pulled taut against the screw shaft and behind the hamstring graft bundles and will then be compressed together with the hamstring graft loop under the bone washer. It should be noted that the PCL/ MFL remnant remains with significant integrity at the femur. The free ends of the hamstring graft have passed through the medial femoral tunnel.
all incisions. A compression dressing should be applied with a posterior plaster slab or a hinged knee brace in extension. Full cast immobilization is usually unnecessary with these procedures. Postoperative Rehabilitation The patient should be encouraged to perform active quadriceps exercises starting on the first postoperative day, and gentle, passive knee flexion to no more than 60 is allowed in the hinged knee brace. Strict noneweightbearing ambulation is emphasized. Partial weight bearing is acceptable after 2 to 3 weeks only when the knee is in extension. The patient can resume full weight bearing in the brace after 6 to 8 weeks if active knee extension is full. The brace can then be discarded when knee flexion exceeds 90 .
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Fig 5. Flow diagram showing the steps of the tibial inlay technique using semitendinosus (SMT) and gracilis (G) tendon graft for PCL reconstruction and PCL and/or MFL remnant revision to be fixed under tension at the tibia using a bone washer. Symbols with a solid arrow indicate activity performed by the surgeon; symbols with a dashed arrow indicate activity optionally performed by the assistant.
Discussion The conventional requisite of using a bone block to be “inlayed” into the posterior tibial socket causes limitation to graft options. Our technique not only broadens utilization of the tibial inlay concept but also reduces donorsite morbidity, which is usually more severe after the composite graft harvest including bone tissue. In addition, the style of the patient setup that allows easy conversion between anterior and posterior approaches facilitates the entire operative procedure and can reduce anesthetic time. Secure “intraosseous” fixation of soft tissues using a bone washer will not produce graft abrasion at the killer turn as is proposed in the transtibial technique. We have not encountered clinical graft failure related to
this intraosseous anchorage of the soft tissue for various purposes, although we have never obtained the healed tissues from the boneesoft tissueebone interface for histologic study. Concomitant fixation of the PCL/MFL remnant (if appropriate) under tension and driving the cancellous screw home in the final step help increase immediate posterior joint stability. Preservation of the remnant tissues might enhance graft healing,5 and the procedure has been incorporated in the transtibial technique in many studies.10,11 Moreover, tensioning of the remnant has been shown to also improve posterior stability when combined with PCL reconstruction in a modified inlay technique.12 However, remnant preservation without tensioning might not increase posterior stability or
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Table 1. Advantages, Indications, Contraindications, Tips and Pearls, Pitfalls and Risks, Key Points, and Limitations of Tibial Inlay Technique Using Hamstring Graft for PCL Reconstruction and Remnant Revision Advantages The choices of graft source are extended compared with the conventional tibial inlay technique. No killer-turn effect occurs while using soft-tissue graft compared with the transtibial technique. Morbidity of the autograft donor site is diminished compared with the conventional tibial inlay technique. Concomitant revision is permitted with tensioning of the PCL remnant at the tibia as an augmentation of reconstruction. Indications For reconstruction: PCL deficiency requiring reconstruction using the tibial inlay technique, especially when only soft-tissue graft is available. For remnant revision: The femoral part of the anterolateral or posteromedial bundle of the PCL and/or MFL remains integral with good continuity to the tibia. Contraindications PCL-deficient knee complicated by inflammatory arthritis or joint stiffness. Acute injury where popliteal neurovascular complications are yet to be ruled out. Tips and pearls First applying a wire-loop suture retriever through the femoral tunnel toward the posterior compartment facilitates passing of the graft from that compartment. Applying a commercial washer on top of the bone washer ensures secure compression in the socket despite accidental breakage of the bone washer. Driving the cancellous screw home at the final stage with readjustment of the remnant tension further improves posterior knee stability. Pitfalls and risks Protruded cancellous screw tip or inserting the screw too medially can irritate anterior soft tissues at the proximal tibia. Prolonged immobilization in extension, though believed to prevent graft laxity, usually results in loss of full knee flexion. Premature weight bearing with the knee in flexion is detrimental to the overall results. Key points Adequate exposure of the posterior compartment with meticulous repair of the opened posterior capsule is essential, especially to revise the remnant. Parallel correction of accompanying posterolateral and/or posteromedial rotatory instability is a crucial factor creating combined effects on posterior knee stability. Limitations Significant scar tissue in the popliteal fossa, obesity, and short stature can cause difficulty in the posterior approach. Conditions that limit ipsilateral hip flexion, abduction, and/or external rotation can produce problems in setup positioning of the patient.
provide clinically superior outcomes compared with the PCL reconstruction without remnant preservation.13 During harvesting of the bone washer, an accidental split of the bone block might occur. This does not compromise the procedure because the fragments can be recomposed, contained, and compressed in situ under the commercial washer. In the sagittal plane, the center of the working fibers of the PCL lies 7 mm anterior to the posterior cortex of the tibia.14 This finding supports our placement of the graft in the tibial socket, where the bone block is approximately 7 mm thick.
References 1. May JH, Gillette BP, Morgan JA, Krych AJ, Stuart MJ, Levy BA. Transtibial versus inlay posterior cruciate ligament reconstruction: An evidence-based systematic review. J Knee Surg 2010;23:73-79. 2. Oakes DA, Markolf KL, McWilliams J, Young CR, McAllister DR. Biomechanical comparison of tibial inlay and tibial tunnel techniques for reconstruction of the posterior cruciate ligament: Analysis of graft forces. J Bone Joint Surg Am 2002;84:938-944. 3. Berg EE. Posterior cruciate ligament tibial inlay reconstruction. Arthroscopy 1995;11:69-76. 4. Laupattarakasem W, Wipulakorn K, Saengnipanthkul S, Kowsuwon W. Intraosseous anchorage of the iliotibial band graft. J Bone Joint Surg Br 1990;72:725.
5. Ahn JH, Yang HS, Jeong WK, Koh KH. Arthroscopic transtibial posterior cruciate ligament reconstruction with preservation of posterior cruciate ligament fibers: Clinical results of minimum 2-year follow-up. Am J Sports Med 2006;34:194-204. 6. Shon OJ, Lee DC, Park CH, Kim WH, Jung KA. A comparison of arthroscopically assisted single and double bundle tibial inlay reconstruction for isolated posterior cruciate ligament injury. Clin Orthop Surg 2010;2: 76-84. 7. Handy MH, Blessey PB, Kline AJ, Miller MD. The graft/ tunnel angles in posterior cruciate ligament reconstruction: A cadaveric comparison of two techniques for femoral tunnel placement. Arthroscopy 2005;21:711-714. 8. Burks RT, Schaffer JJ. A simplified approach to the tibial attachment of the posterior cruciate ligament. Clin Orthop Relat Res 1990:216-219. 9. Markolf KL, Graves BR, Sigward SM, Jackson SR, McAllister DR. Popliteus bypass and popliteofibular ligament reconstructions reduce posterior tibial translations and forces in a posterior cruciate ligament graft. Arthroscopy 2007;23:482-487. 10. Zhao J, Xiaoqiao H, He Y, Yang X, Liu C, Lu Z. Sandwichstyle posterior cruciate ligament reconstruction. Arthroscopy 2008;24:650-659. 11. Yoon KH, Bae DK, Song SJ, Cho HJ, Lee JH. A prospective randomized study comparing arthroscopic single-bundle and double-bundle posterior cruciate ligament reconstructions preserving remnant fibers. Am J Sports Med 2011;39:474-480.
HAMSTRING TIBIAL INLAY TECHNIQUE 12. Lee KH, Jung YB, Jung HJ, et al. Combined posterolateral corner reconstruction with remnant tensioning and augmentation in chronic posterior cruciate ligament injuries: Minimum 2-year follow-up. Arthroscopy 2011;27:507-515. 13. Kim SJ, Kim SH, Chun YM, Hwang BY, Choi DH, Yoon JY. Clinical comparison of conventional and remnant-preserving transtibial single-bundle posterior
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cruciate ligament reconstruction combined with posterolateral corner reconstruction. Am J Sports Med 2012;40: 640-649. 14. Moorman CT III, Murphy Zane MS, Bansai S, et al. Tibial insertion of the posterior cruciate ligament: A sagittal plane analysis using gross, histologic, and radiographic methods. Arthroscopy 2008;24:269-275.
Abstract: The posterior tibial inlay technique is currently accepted as a standard operation for the posterior cruciate ligamentedeficient knee. The classical technique requires a graft construct consisting of a bony part to be fitted into the posterior tibial socket. When an autogenous source is chosen, morbidity at the donor site generated by obtaining the graft with a bony part (e.g., boneepatellar tendonebone or quadriceps tendonebone) can be more serious than when obtaining the soft-tissue graft (e.g., hamstring). This study describes an alternative use of soft-tissue graft anchored in a bone socket at the posterior tibial margin by a transfixing cancellous screw. The graft is secured on top by a “bone washer” harvested from this bone socket to provide biological bone-tendon-bone healing. The posterior cruciate ligament remnant with integral fibers at the femur can have its tibial part revised, tensioned, and reattached concomitantly. This additional procedure is deemed to enhance joint stability and promote graft healing.
S
urgery to restore posterior stability of the posterior cruciate ligament (PCL)edeficient knee is still inconclusive regarding the most reliable and least technically challenging approach.1,2 The arthroscopically assisted transtibial technique uses either a boneesoft tissue construct or a graft of soft tissue alone, whereas the classical open tibial inlay procedure requires a composite graft containing a bony part to be fixed into the posterior tibial socket. The inherent benefits of the inlay technique are its anatomic replacement and avoidance of the acute graft bending, or “killer turn,” that can cause graft laxity, as is commonly seen after the transtibial technique.3 However, in places lacking allogeneic graft or declining its use, harvesting autogenous tissues associated with a bony part (e.g., boneepatellar tendonebone or quadriceps tendonebone) usually can produce more serious donor-site morbidity than when obtaining only
soft tissues (e.g., semitendinosus and gracilis). Alternative use of soft-tissue graft for the tibial inlay technique will therefore extend choices of graft source and increase the flexibility of this approach. We apply the technique described as an “intraosseous anchorage of the soft-tissue graft”4 to our proposition. This technique essentially creates a bone block at the graft anchor site, where the soft-tissue graft is later laid into the resultant bony defect. The bone block, which has been predrilled for a lag screw, is then inserted in situ and functions as a washer compressing over the graft. When using this technique for PCL reconstruction, we often observe essential remnants that remain attached both to the femur and to the tibia. When indicated, this remnant is concomitantly revised and anchored with tension under the same bone washer, to augment joint stability and promote graft healing.
Surgical Techniques From the Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. The authors report that they have no conflicts of interest in the authorship and publication of this article. Received August 6, 2012; accepted September 14, 2012. Address correspondence to Wiroon Laupattarakasem, M.D., Department of Orthopaedics, Srinagarind Hospital Endoscopy Center, Faculty of Medicine, Khon Kaen University, 123 Mitraparp Road, Khon Kaen 40002, Thailand. E-mail: [email protected] Ó 2013 by the Arthroscopy Association of North America 2212-6287/12511/$36.00 http://dx.doi.org/10.1016/j.eats.2012.09.001
The surgery should be performed by a team of operating room personnel who have fully rehearsed changing the patient’s position throughout the course of the operation. General Setup We prefer placing the patient supine on the operating table that is equipped with 2 adjustable leg plates (Alphamaquet; Maquet, Rastatt, Germany) for later readjustment of the position. Arthroscopic procedures of the knee are conducted with the patient in this
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supine position, and the surgeon works by the side. A side post is installed just proximal to the ipsilateral hip joint to support the patient when the table is tilted side down. During the surgical approach to the popliteal area, the supporting leg plate for the operative limb is dropped down or uncoupled while the leg is transferred onto a small rolling work table with locking casters. The ipsilateral hip is abducted and fully externally rotated; the operating table is tilted side down to help open up the posteromedial aspect of the knee. The leg plate supporting the other limb is abducted so that the surgeon can sit between the 2 lower limbs (Fig 1). With this setup, the whole operating procedure can be accomplished without the need to re-scrub and turn the patient 180 upon alternating anterior and posterior approaches. A tourniquet is usually used during the operation if not clinically contraindicated. Graft Preparation If the diagnosis of the PCL deficiency is certain and autogenous soft-tissue grafts are required, semitendinosus and gracilis tendons from the same side are retrieved routinely (Video 1) using a closed tendon stripper (Smith & Nephew, Andover, MA). Otherwise, arthroscopic examination should be performed first to determine the general intra-articular pathology and consider the appropriate surgeries. The grafts can be prepared on a side table by the assistant while the surgeon is working on the knee. The preferred length of each tendon is 18 to 20 cm. The 2 tendons are paired by sewing the proximal end of 1 strand to the distal end of the other strand to create a double-strand graft of similar caliber at both ends. Two No. 2 Vicryl sutures (Ethicon, Somerville, NJ) are affixed at each end by use of running whipstitches. The tendons are doubled into a 9- to 10-cm-long quadrupled construct. The graft construct is then pre-sized and pre-tensioned using the standard devices (Graft Sizing Tubes and GraftMaster System; Smith & Nephew). Arthroscopic Femoral Tunnel Preparation We perform diagnostic arthroscopy using the standard anterolateral and anteromedial portals. Associated intra-articular pathology such as meniscal and cartilage lesions is primarily addressed. Redundant tissues are cleaned, and the anatomic PCL footprint at the medial femoral condyle is located. However, remnant fibers of the PCL and/or meniscofemoral ligament (MFL), if remaining integral at the femoral site, can be preserved.5 These fibers usually are attenuated and attach at the tibial intercondylar area somewhat anterior to the normal position after posterior tibial translation. Single-bundle or double-bundle reconstruction can be planned, although we currently prefer the former6 and emphasize replacing the anterolateral bundle.
Fig 1. Bird’s-eye view showing the scenario for patient setup during the open popliteal approach for the tibial inlay technique. The patient is placed supine on an operating table equipped with 2 modular leg plates. The leg plate supporting the operative knee is dropped down, and the leg is transferred onto a work table with the hip fully externally rotated, flexed, and abducted. The other leg plate is abducted to provide more room for the surgeon to sit between the 2 lower limbs. The operating table is side tilted to further open up the popliteal area.
The surgeon locates the outside-in femoral tunnel entry site through a small incision and medial subvastus dissection at about 1 to 2 cm proximal to the articular margin on the anteromedial aspect of the distal femoral metaphysis. By use of the PCL femoral aimer (Acufex Director; Smith & Nephew), the medial femoral tunnel conforming to the graft size is reamed into the anterolateral bundle footprint (at around the 11- or 1-o’clock position as appropriate). The surgeon should guard the remnant fibers away from the exiting reamer by the hoop tip of the aimer. The direction of the tunnel should be closely aligned with the PCL axis, and the aperture rim is beveled with a bone tunnel chamfering rasp (Smith & Nephew) to reduce graft-tunnel divergence and aperture impingement to the intra-articular part of the graft.7 A 1.0-mm-diameter wire-loop suture retriever is passed through the tunnel, lying medial to the anterior cruciate ligament and toward the posterior compartment. This preparation will significantly facilitate the passage of the graft from the posterior compartment in the next step. Open Posterior Approach If a tourniquet is being used, it is intermittently released and inflated again during this step while the patient’s position is readjusted, as mentioned earlier. The posterior knee compartment is approached through a posteromedial hockey-stick incision with its straight arm placed just lateral to the medial hamstring.8 The interval between the medial head of the gastrocnemius and the semimembranosus tendon is identified and
HAMSTRING TIBIAL INLAY TECHNIQUE
bluntly dissected to expose the posterior capsule. The tibial condyle is more eminent at its posteromedial aspect, which can increase the difficulty of the approach. The posterior tibial fovea where the normal PCL attaches is palpated. The surgeon opens the posterior capsule by incising along the lateral border of the medial femoral condyle, crossing the joint line and continuing distally medial to the fovea to adequately expose the posterior compartment. The tip of a Hohmann retractor can be hammered into the lateral part of the proximal tibia to help lever away the capsular flap for better exposure. The PCL footprint and redundant tissues are identified and cleaned. If the PCL/MFL remnant at the femur remains with significant thickness and continuity at the tibia, the structure usually has laxity when the posterior tibial translation is reduced. In this case, the surgeon should identify the anterior border of the remnant attachment and, using a small osteotome, peel the structure off from the tibial intercondylar area, together with a thin layer of cortex where it attaches. The surgeon repairs and augments the stump with 2 nonabsorbable sutures (Ethibond Excel 5; Ethicon), leaving suture tails for remnant tensioning and fixation during the next step (not shown in Video 1). Bone Washer Preparation First, the surgeon drills a 3.2-mm core hole for a 6.5-mm cancellous screw (Synthes, Oberdorf, Switzerland) within the PCL footprint at about 1 cm distal to the posterior tibial margin. The drill bit should be targeted toward the anterolateral aspect of the proximal tibia to minimize possible conflict with the future transtibial drill path aimed from the anteromedial aspect. The surgeon then measures the depth and pre-taps the hole for the cancellous screw thread. Using an osteotome or reciprocating saw as appropriate, he or she removes a piece of 7mm-thick unicortical bone block, about 15 20 mm in size, with the screw hole in the middle (Fig 2). A partially threaded cancellous screw is inserted into the bone block, which will now act as a bone washer. A commercial metal or spiked washer should be added to back up this bone washer. Graft Passage Using the wire-loop suture retriever previously placed in the posterior compartment, the surgeon pulls the affixing sutures leading the free graft ends past the compartment into the femoral tunnel. A strip of the umbilical tape temporarily appended to the graft loop helps in controlling the graft passage, as shown in Video 1. The surgeon slings the looped end over the cancellous screw shaft and in front of the bone washer. The screw shaft is now acting as a transfixing post of the graft (Fig 3). If the PCL/MFL remnant has been previously prepared, the posterior tibial sagging is primarily
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Fig 2. Outline for the harvest of the unicortical bone block from the footprint area of the PCL at the tibia. This material will subsequently function as the bone washer. The black dot represents the central drill hole for the cancellous screw.
reduced. The remnant is then pulled taut against either side of the screw shaft and anterior or posterior to the graft loop, according to the anatomy of the remnant bundle (Fig 4). The screw is inserted into the predrilled hole until the bone washer is seated in situ, sandwiching the graft (and the remnant with sutures) against the bony socket. Intentionally, the screw is only moderately fastened at this step. Graft Fixation at Femur The surgeon tightly pulls the graft ends now already located in the femoral tunnel. To ensure proper graft position in the joint, this is arthroscopically checked without fluid instillation (because the posterior capsule is still open). The knee is flexed and extended several times to lessen any slackened tissue. The proximal tibia is pulled anteriorly with the knee flexed at about 80 , and a bioabsorbable interference screw is inserted in an outside-in manner to secure the graft ends. The affixing sutures should be post-tied as a backup fixation. Wrapping Up Having fixed the graft ends posteriorly at the tibia and anteromedially at the femur, the posterior-drawer sign should now be negative with normal anteromedial tibial step off and the knee can be mobilized in full range. The surgeon should return to the posterior operative field again to drive the cancellous screw snugly home. If the PCL/MFL remnant is being fixed, the screw should be slightly loosened to pull the remnant tight before
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Fig 3. The hamstring graft bundles are slung over the cancellous screw shaft for the tibial inlay technique using this graft for PCL reconstruction. The affixed sutures leading the free ends of the graft have been introduced into the medial femoral tunnel from the posterior compartment. The bone washer will then be driven together with the commercial washer to compress on the transfixed hamstring graft against the bone socket bed.
driving the screw. This step will further tension the graft (and the remnant) being sandwiched between the bone washer and the bone socket bed. If desired, the affixing sutures to the remnant can be pulled out anteriorly through separate drill tracks parallel to the screw and post-tied at the tibia. The treatment algorithm is presented in the flow diagram (Fig 5). Advantages, indications, contraindications, tips and pearls, pitfalls and risks, key points, and limitations of the procedure are further described in Table 1. We recommend immediate correction of any associated posterolateral and/or posteromedial rotatory instability to warrant combined effects on stabilization of the posterior tibial translation.9 The surgeon should retain a vacuum drainage and meticulously repair the posterior capsule before closing
Fig 4. The peeled-off remnant fibers of the PCL and/or MFL with a thin layer of the attaching bone plate at the tibia are augmented with sutures. The remnant is pulled taut against the screw shaft and behind the hamstring graft bundles and will then be compressed together with the hamstring graft loop under the bone washer. It should be noted that the PCL/ MFL remnant remains with significant integrity at the femur. The free ends of the hamstring graft have passed through the medial femoral tunnel.
all incisions. A compression dressing should be applied with a posterior plaster slab or a hinged knee brace in extension. Full cast immobilization is usually unnecessary with these procedures. Postoperative Rehabilitation The patient should be encouraged to perform active quadriceps exercises starting on the first postoperative day, and gentle, passive knee flexion to no more than 60 is allowed in the hinged knee brace. Strict noneweightbearing ambulation is emphasized. Partial weight bearing is acceptable after 2 to 3 weeks only when the knee is in extension. The patient can resume full weight bearing in the brace after 6 to 8 weeks if active knee extension is full. The brace can then be discarded when knee flexion exceeds 90 .
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Fig 5. Flow diagram showing the steps of the tibial inlay technique using semitendinosus (SMT) and gracilis (G) tendon graft for PCL reconstruction and PCL and/or MFL remnant revision to be fixed under tension at the tibia using a bone washer. Symbols with a solid arrow indicate activity performed by the surgeon; symbols with a dashed arrow indicate activity optionally performed by the assistant.
Discussion The conventional requisite of using a bone block to be “inlayed” into the posterior tibial socket causes limitation to graft options. Our technique not only broadens utilization of the tibial inlay concept but also reduces donorsite morbidity, which is usually more severe after the composite graft harvest including bone tissue. In addition, the style of the patient setup that allows easy conversion between anterior and posterior approaches facilitates the entire operative procedure and can reduce anesthetic time. Secure “intraosseous” fixation of soft tissues using a bone washer will not produce graft abrasion at the killer turn as is proposed in the transtibial technique. We have not encountered clinical graft failure related to
this intraosseous anchorage of the soft tissue for various purposes, although we have never obtained the healed tissues from the boneesoft tissueebone interface for histologic study. Concomitant fixation of the PCL/MFL remnant (if appropriate) under tension and driving the cancellous screw home in the final step help increase immediate posterior joint stability. Preservation of the remnant tissues might enhance graft healing,5 and the procedure has been incorporated in the transtibial technique in many studies.10,11 Moreover, tensioning of the remnant has been shown to also improve posterior stability when combined with PCL reconstruction in a modified inlay technique.12 However, remnant preservation without tensioning might not increase posterior stability or
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Table 1. Advantages, Indications, Contraindications, Tips and Pearls, Pitfalls and Risks, Key Points, and Limitations of Tibial Inlay Technique Using Hamstring Graft for PCL Reconstruction and Remnant Revision Advantages The choices of graft source are extended compared with the conventional tibial inlay technique. No killer-turn effect occurs while using soft-tissue graft compared with the transtibial technique. Morbidity of the autograft donor site is diminished compared with the conventional tibial inlay technique. Concomitant revision is permitted with tensioning of the PCL remnant at the tibia as an augmentation of reconstruction. Indications For reconstruction: PCL deficiency requiring reconstruction using the tibial inlay technique, especially when only soft-tissue graft is available. For remnant revision: The femoral part of the anterolateral or posteromedial bundle of the PCL and/or MFL remains integral with good continuity to the tibia. Contraindications PCL-deficient knee complicated by inflammatory arthritis or joint stiffness. Acute injury where popliteal neurovascular complications are yet to be ruled out. Tips and pearls First applying a wire-loop suture retriever through the femoral tunnel toward the posterior compartment facilitates passing of the graft from that compartment. Applying a commercial washer on top of the bone washer ensures secure compression in the socket despite accidental breakage of the bone washer. Driving the cancellous screw home at the final stage with readjustment of the remnant tension further improves posterior knee stability. Pitfalls and risks Protruded cancellous screw tip or inserting the screw too medially can irritate anterior soft tissues at the proximal tibia. Prolonged immobilization in extension, though believed to prevent graft laxity, usually results in loss of full knee flexion. Premature weight bearing with the knee in flexion is detrimental to the overall results. Key points Adequate exposure of the posterior compartment with meticulous repair of the opened posterior capsule is essential, especially to revise the remnant. Parallel correction of accompanying posterolateral and/or posteromedial rotatory instability is a crucial factor creating combined effects on posterior knee stability. Limitations Significant scar tissue in the popliteal fossa, obesity, and short stature can cause difficulty in the posterior approach. Conditions that limit ipsilateral hip flexion, abduction, and/or external rotation can produce problems in setup positioning of the patient.
provide clinically superior outcomes compared with the PCL reconstruction without remnant preservation.13 During harvesting of the bone washer, an accidental split of the bone block might occur. This does not compromise the procedure because the fragments can be recomposed, contained, and compressed in situ under the commercial washer. In the sagittal plane, the center of the working fibers of the PCL lies 7 mm anterior to the posterior cortex of the tibia.14 This finding supports our placement of the graft in the tibial socket, where the bone block is approximately 7 mm thick.
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5. Ahn JH, Yang HS, Jeong WK, Koh KH. Arthroscopic transtibial posterior cruciate ligament reconstruction with preservation of posterior cruciate ligament fibers: Clinical results of minimum 2-year follow-up. Am J Sports Med 2006;34:194-204. 6. Shon OJ, Lee DC, Park CH, Kim WH, Jung KA. A comparison of arthroscopically assisted single and double bundle tibial inlay reconstruction for isolated posterior cruciate ligament injury. Clin Orthop Surg 2010;2: 76-84. 7. Handy MH, Blessey PB, Kline AJ, Miller MD. The graft/ tunnel angles in posterior cruciate ligament reconstruction: A cadaveric comparison of two techniques for femoral tunnel placement. Arthroscopy 2005;21:711-714. 8. Burks RT, Schaffer JJ. A simplified approach to the tibial attachment of the posterior cruciate ligament. Clin Orthop Relat Res 1990:216-219. 9. Markolf KL, Graves BR, Sigward SM, Jackson SR, McAllister DR. Popliteus bypass and popliteofibular ligament reconstructions reduce posterior tibial translations and forces in a posterior cruciate ligament graft. Arthroscopy 2007;23:482-487. 10. Zhao J, Xiaoqiao H, He Y, Yang X, Liu C, Lu Z. Sandwichstyle posterior cruciate ligament reconstruction. Arthroscopy 2008;24:650-659. 11. Yoon KH, Bae DK, Song SJ, Cho HJ, Lee JH. A prospective randomized study comparing arthroscopic single-bundle and double-bundle posterior cruciate ligament reconstructions preserving remnant fibers. Am J Sports Med 2011;39:474-480.
HAMSTRING TIBIAL INLAY TECHNIQUE 12. Lee KH, Jung YB, Jung HJ, et al. Combined posterolateral corner reconstruction with remnant tensioning and augmentation in chronic posterior cruciate ligament injuries: Minimum 2-year follow-up. Arthroscopy 2011;27:507-515. 13. Kim SJ, Kim SH, Chun YM, Hwang BY, Choi DH, Yoon JY. Clinical comparison of conventional and remnant-preserving transtibial single-bundle posterior
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cruciate ligament reconstruction combined with posterolateral corner reconstruction. Am J Sports Med 2012;40: 640-649. 14. Moorman CT III, Murphy Zane MS, Bansai S, et al. Tibial insertion of the posterior cruciate ligament: A sagittal plane analysis using gross, histologic, and radiographic methods. Arthroscopy 2008;24:269-275.