Abstract
Posterior cruciate ligament (PCL) reconstruction using the transtibial drilling or arthroscopic tibial-inlay technique has a risk of injury to the popliteal neurovascular bundle because a pin is drilled anterior to posterior. Intraoperative fluoroscopy is used to decrease the risk of neurovascular injury. In addition, graft passage in the transtibial technique may be problematic because of a sharp turn when placing the graft into the tibial tunnel, which may damage graft fibers. In the surgical technique described in this report, the posteromedial portal is used for visualization and the posterolateral portal is used for debridement of the PCL tibial footprint and the synovial fold closest to the PCL. A curved guide is placed from the posterolateral portal to the tibial footprint, and a flexible pin is drilled across the tibia. The tibial tunnel is then created using a flexible reamer under direct visualization up to the desired length, and a graft can be positioned in the tibial tunnel through the posterolateral portal. This technique has the potential advantages of decreasing the risk of injury to the popliteal neurovascular bundle (use of anteriorly directed, inside-out drilling), avoiding a sharp turn during graft passage, and allowing accurate and anatomic tibial tunnel placement without intraoperative fluoroscopy.
Posterior cruciate ligament (PCL) reconstruction is a challenging procedure. There are several potential complications associated with PCL reconstruction, and damage to the popliteal neurovascular bundle is especially concerning.1 Preparation of the tibial tunnel is a critical part of the reconstruction in terms of the risk of potential neurovascular injury. There are 2 main surgical techniques described to create the tibial attachment site in PCL reconstruction: the transtibial and tibial-inlay techniques (both can be performed either arthroscopically or as an open procedure). The arthroscopic or open transtibial technique uses a posteriorly directed, antegrade drilling method through any of the available PCL tibial guides and passes the graft usually through the tibial tunnel. The arthroscopic tibial-inlay technique uses anteriorly directed, inside-out retrograde drilling to create the tibial attachment site, and the graft is passed from a portal into the tibial footprint. In both cases a pin is first drilled in an outside-in manner from anterior to posterior, risking injury to the popliteal neurovascular bundle. Intraoperative fluoroscopy is frequently used to assess both adequate location of the tibial PCL guide tip and absence of pin penetration beyond the posterior cortex of the PCL tibial footprint. In addition, graft passage in the transtibial technique may be problematic because of a sharp turn when going from the tibial to the femoral tunnel. This sharp turn in the back of the tibia has been shown to damage graft fibers.2 The purpose of this technical article is to report an easily reproducible and relatively safe method to create the tibial tunnel in PCL reconstruction that decreases the risk of popliteal neurovascular bundle injury, avoids a sharp turn during graft passage, and allows accurate tibial tunnel placement without intraoperative fluoroscopy.
Surgical Technique
The patient should be positioned supine with the knee flexed and the leg and foot hanging over the end of the bed. The operative extremity is prepared and draped in the usual fashion for routine knee arthroscopy. The procedure can be performed with a standard 30° arthroscope. The anteromedial and anterolateral portals are created close to the patellar tendon to facilitate the visualization of the posteromedial and posterolateral aspects of the knee. The PCL remnant is excised using the anterior portals (Table 1). Alternatively, the knife may be only used for skin incision and then a straight or curved snap employed to get access to the joint. This may decrease the risk of damaging the saphenous nerve. The arthroscope is then used to visualize the posteromedial aspect of the knee through the anterolateral portal. Under direct visualization, a spinal needle is used to gain access to the posteromedial knee; then, a No. 11 blade knife is used to create an opening within the capsule that is large enough to place a 10-mm cannula (PassPort cannula; Arthrex, Naples, FL) (Table 1). The arthroscope is placed in the anteromedial portal and advanced into the posterolateral aspect of the knee. The same methods can be used to create the posterolateral portal and place a second cannula (Table 1). It is important to create a posterolateral portal and skin incisions that are at least 10 mm to facilitate the introduction of the flexible reamer and graft in subsequent steps.
Table 1.
Summary of Key Points of Surgical Technique
| Step-by-Step Technique | Description |
|---|---|
| Step 1: Debridement of PCL remnants | Visualization: arthroscope in anterolateral portal |
| Instruments: arthroscopic scissors (if needed), shaver, and tissue ablation device | |
| Technical tip: Instruments are placed through the anteromedial portal for PCL debridement. The working and viewing portals can be switched as needed. | |
| Step 2: Creation of posteromedial portal | Visualization: arthroscope in anterolateral portal |
| Instruments: spinal needle, No. 11 blade knife, and cannula (threaded cannula with 7 mm diameter is recommended) | |
| Technical tip: The surgeon should not remove the spinal needle when using the knife but, instead, try to slide through the needle to help follow the same direction. This may be helpful at the beginning for surgeons with less experience using posterior portals. | |
| Step 3: Creation of posterolateral portal | Visualization: arthroscope in anteromedial portal |
| Instruments: spinal needle, No. 11 blade knife, and temporal cannula (threaded cannula with 7 mm diameter is recommended) | |
| Technical tip: Same as step 2. | |
| Step 4: Creation of trans-septal portal | Visualization: arthroscope in posteromedial portal |
| Instruments: pointed Wissinger-like rod from posterolateral portal | |
| Technical tip: The surgeons should make sure the rod is sufficiently crossed in a posterior-to-anterior direction (approximately 30° in the coronal plane) to avoid violation of the posterior aspect of the septum (causes more bleeding) or posterior capsule (places popliteal neurovascular bundle at risk of injury). | |
| Step 5: Preparation of PCL tibial footprint | Visualization: arthroscope in posteromedial portal |
| Instruments: 4.5 or 5.5 mm shaver and tissue ablation device from posterolateral portal | |
| Technical tip: The surgeon should avoid facing posterior with the shaver or tissue ablation device to prevent more bleeding or violation of the posterior capsule. | |
| Step 6: Preparation of tibial tunnel or socket | Visualization: arthroscope in posteromedial portal |
| Instruments: curved guide and flexible pin from posterolateral portal | |
| Technical tip: The curved guide has to be twisted in an external rotation and anterior fashion (Fig 3, Video 1); the knee can be flexed beyond 90° (105°-110° is recommended); then, the flexible pin is advanced. | |
| Step 7: Creation of tibial tunnel or socket | Visualization: arthroscope in posteromedial portal |
| Instruments: flexible reamer (10 mm or 11 mm depending on desired graft size) | |
| Technical tip: The reamer should enter in the joint by manual twisting to avoid injury to the septum and posterior capsule. Then, the tibial tunnel or socket is created to the desired length under direct visualization. | |
| Step 8: Placement of graft into tibial attachment site | Visualization: arthroscope in posteromedial portal |
| Instruments: flexible pin used as suture passer | |
| Technical tip: Sutures placed in the graft are passed through the hole in the flexible pin, which will be used to pass the sutures to the tibial site by pulling the pin distally from the exit point in the anteromedial aspect of the proximal tibial. Then, the sutures are pulled distally to enter the graft into the joint and place it in the tibial attachment site. | |
| Step 9: Passing of graft anteriorly for femur fixation | Visualization: arthroscope in posteromedial portal |
| Instruments: 2 arthroscopic suture retrievers | |
| Technical tip: An arthroscopic suture retriever is used to take the sutures outside of the joint in the proximal end of the graft (the sutures are exiting the posterolateral portal), and the instrument is advanced inside the joint through the posterolateral portal until it is visualized from the posteromedial portal. Another suture retriever is entered from the anteromedial portal, and the sutures are pulled outside the joint anteriorly, bringing the graft into the anterior compartment. | |
| Step 10: Fixation of tibial attachment | Visualization: arthroscope in posteromedial portal |
| Instruments: suspensory cortical fixation device (button fixation after creating tibial socket) or direct tibial fixation (screw and/or staples after creating tibial tunnel), both placed in anteromedial cortex of proximal tibia | |
| Technical tip: As performed in anterior cruciate ligament reconstruction. |
PCL, posterior cruciate ligament.
The arthroscope is placed in the posteromedial portal, and a pointed Wissinger-like rod is advanced from the posterolateral compartment (Fig 1A, Video 1) to create the trans-septal portal (Table 1, Fig 1B, Video 1). Once posterior triangulation is achieved, a shaver is used from the posterolateral portal to complete the excision of the PCL tibial remnant. Care must be taken to not violate the posterior aspect of the septum and capsule to prevent bleeding and avoid damage to the popliteal neurovascular bundle. An electrical tissue ablation device (Quantum 2 System; ArthroCare Sports Medicine, Sunnyvale, CA) can also be used to excise the PCL remnants and the synovial fold closest to the PCL, to mark the anatomic tibial footprint where the tunnel will be created, and to clean the tibial footprint from soft tissue that would interfere with the insertion of the graft into the tibial tunnel (Table 1). A flexible reaming system (VersiTomic Flexible Reaming System; Stryker, Greenwood Village, CO) is used to create the tibial attachment site. The curved guide is inserted through the posterolateral portal and placed at the tibial PCL footprint under direct visualization from the posteromedial portal (Table 1, Fig 2, Video 1). A flexible pin is then advanced through the curved guide until the tibial footprint is reached. Then, the curved guide is twisted in an anterior and externally rotated fashion to facilitate the appropriate track of the flexible pin so that it will exit in the proximal-anteromedial aspect of the tibia (Table 1, Fig 3, Video 1). A slight increase in knee flexion beyond 90° is helpful to have the tibial footprint facing more perpendicular to the curved guide, improving the direction of the tunnel and avoiding slippage of the guide in the tibial footprint. The flexible pin is then advanced (Fig 4A, Video 1) to exit between the anterior tibial tubercle and the distal attachment of the medial collateral ligament. We recommend removing the 10-mm-diameter cannula placed in the posterolateral portal even if the reamer and the graft bone block are not greater than 10 mm. This will facilitate the entrance of the reamer into the knee and graft passage in subsequent steps. A flexible reamer of appropriate size is placed over the flexible guide pin (Fig 4B, Video 1) and advanced to its starting position by hand to avoid catching soft tissue posteriorly (Table 1). The flexible reamer is used to create a tibial tunnel that either exits in the anteromedial cortex of the tibia or creates a socket for the bone plug with planned fixation in the anteromedial cortex using a button system.
Fig 1.
Arthroscopic view of the posterior cruciate ligament (PCL) remnant from the posteromedial portal and creation of the trans-septal portal. (A) A sharp-pointed Wissinger-like rod is introduced through the posterolateral portal and advanced into the PCL remnant by penetrating the septum (trans-septal portal). This step is performed under direct visualization from the posteromedial portal. (B) Arthroscopic view from the posteromedial portal showing the trans-septal portal. (ACL, anterior cruciate ligament; LFC, lateral femoral condyle; MFC, medial femoral condyle; MTP, medial tibial plateau.)
Fig 2.
Arthroscopic view from the posteromedial portal showing the curved guide advancing through the posterolateral portal down to the posterior cruciate ligament (PCL) footprint. The knee can be flexed beyond 90° (approximately at 110°) to facilitate guide placement and avoid slippage of the tip from the PCL footprint. (LFC, lateral femoral condyle; LTP, lateral tibial plateau.)
Fig 3.
External view of the knee showing placement of the curved guide in the posterolateral portal and the rotational movement needed to obtain the appropriate location and direction of the posterior cruciate ligament tibial tunnel. The hand has to be externally rotated and anteriorly directed in combination with a slight increase in knee flexion (approximately 110° of knee flexion) to facilitate the adequate location and direction of the tibial tunnel or socket.
Fig 4.
Arthroscopic view through the posteromedial portal showing the position of the flexible pin and reamer. (A) Flexible pin entering the joint from the posterolateral portal down to the posterior cruciate ligament (PCL) tibial footprint. (B) Use of the flexible reamer to create the PCL tibial tunnel. To avoid damage to the posterior septum (prevent bleeding) and joint capsule, it is important to advance the reamer by hand to obtain entrance into the joint and to not ream until the tip of the reamer reaches the bone. (LFC, lateral femoral condyle; LTP, lateral tibial plateau.)
Once the tunnel is created, the flexible reamer is removed and the flexible pin is used to pass the sutures placed in one end of the graft from the posterolateral portal through the tibial tunnel, exiting in the anteromedial aspect of the proximal tibia (Table 1). The graft is then passed into the tibial tunnel through the posterolateral portal by pulling the sutures exiting the anteromedial aspect of the tibia (Table 1, Fig 5, Video 1). A grasper is used to bring the sutures placed in the other end of the graft inside the joint from the posterolateral portal, and a ring grasper is used from the anteromedial portal to retrieve the sutures to the anterior aspect of the knee for the fixation of the femoral site (Table 1, Fig 6, Video 1). The graft is then pulled from the anteromedial portal and advanced to the anterior compartment (Fig 7, Video 1). At this stage, femoral tunnel drilling and fixation can be performed through any of the available surgical techniques (Table 1). Table 2 summarizes the pitfalls/risks and potential solutions for this surgical technique.
Fig 5.
Arthroscopic view from the posteromedial portal showing how the graft is placed into the tibial attachment site. The posterior cruciate ligament (PCL) graft has been introduced through the posterolateral portal. The sutures in the tibial end of the graft are introduced into the hole of the flexible pin. The pin is then pulled distally to bring the sutures into the tibial tunnel. (LFC, lateral femoral condyle; LTP, lateral tibial plateau.)
Fig 6.
Arthroscopic view from the posteromedial portal showing transfer of the posterior cruciate ligament (PCL) graft from the posterolateral to anterior aspect of knee. (A) A grasper is used to bring the sutures of the proximal end of the PCL graft into the joint through the posterolateral portal. A ring grasper can be used to avoid a soft-tissue bridge by sliding the grasper over the sutures so that it follows the same direction of the sutures. (B) A ring grasper is used to retrieve the sutures from the proximal end of the PCL graft to the anterior aspect of the knee from the anteromedial portal. (ACL, anterior cruciate ligament; MFC, medial femoral condyle; MTP, medial tibial plateau.)
Fig 7.
Arthroscopic view from the posteromedial portal showing the correct positioning of the posterior cruciate ligament (PCL) in the tibial attachment site and its anterior direction toward the femoral attachment site. (LFC, lateral femoral condyle; LTP, lateral tibial plateau; MFC, medial femoral condyle; MM, medial meniscus.)
Table 2.
Potential Pitfalls/Risks and Recommended Solutions for Surgical Technique
| Pitfalls/Risks | Solutions |
|---|---|
| Damage to popliteal neurovascular bundle |
|
| Damage to the saphenous nerve when creating the posteromedial portal |
|
| Damage to posterior aspect of synovial recess and posterior capsule when performing tibial footprint debridement |
|
| Difficulty reaching anatomic tibial footprint with adequate angle using curved guide | • Use a high posterolateral portal. |
| Slippage of curved guide in tibial footprint | • Place the knee in flexion slightly beyond 90° (approximately 110°) |
| Damage to synovial recess and posterior capsule when creating tibial tunnel or socket | • Enter the flexible reamer into the knee by hand, twisting instead of power. |
| Difficult graft passage into joint from posterolateral portal | • Create a large posterolateral portal (10 mm). |
| Soft-tissue bridge when bringing proximal sutures placed into graft to anterior aspect of knee | • Use a ring grasper to slide over the sutures of the proximal end of the graft so that the grasper follows the same direction of the sutures through the posterolateral portal. |
| Tibial tunnel too close to joint line or too medial in proximal tibia |
|
Discussion
This technical article describes an easily reproducible and relatively safe method to create the tibial tunnel in PCL reconstruction. This method uses an anteriorly directed, inside-out drilling technique by using a flexible pin and reamer through the posterolateral portal under direct visualization from the posteromedial portal.
The transtibial (either arthroscopic or open) drilling technique has been extensively used with good clinical and functional results.3, 4 With transtibial drilling, a posteriorly directed pin is drilled from the anteromedial cortex of the proximal tibia using a PCL guide. This places the popliteal neurovascular bundle at risk in cases where the pin misses the tip of the guide. This has led many surgeons to use intraoperative fluoroscopy for verification of adequate pin placement in the footprint and to prevent over-penetration of the pin into the popliteal space. Intraoperative fluoroscopy, however, exposes the patient, the surgeon, and the rest of the operating room team to radiation and may increase operative time. For the purpose of tibial tunnel placement, fluoroscopy can be avoided if an arthroscope is used to place the tip of the PCL guide into the tibial footprint (this may require the use of a 70° arthroscope). However, fluoroscopy will still be needed to ensure that over-penetration of the posteriorly directed pin does not occur. Direct visualization of the tibial footprint is not always easy in cases with a narrow intercondylar notch and an intact anterior cruciate ligament. An incomplete view may require the use of the posteromedial portal for adequate visualization.5 Although an anatomic position of the tibial footprint is possible using transtibial drilling, graft passage with this technique is difficult because of a sharp turn when placing the graft into the tibial tunnel. It has been shown that the sharp turn during the transtibial technique may damage graft fibers.2 The present surgical technique offers an easy method to place the graft into the tibial tunnel without risk of damaging the graft fibers (Video 1). A tibial-inlay technique has been used by several surgeons to avoid this problem. Although good clinical and functional results have also been shown with the tibial-inlay technique,3, 4 it requires a posterior approach to the knee and often requires changing the patient's position during the surgical procedure. These disadvantages were solved with the development of an arthroscopic tibial-inlay technique.6 With the latter, the graft is introduced into the joint through an anteromedial portal, avoiding the sharp turn in the back of the tibia. This technique still requires the use of a posteriorly directed pin drilled from the anteromedial cortex of the proximal tibia under intraoperative fluoroscopy. Although fluoroscopy is not needed in our surgical technique because the pin is drilled anteriorly and the footprint can be clearly seen through the posteromedial portal, a surgeon performing this technique for the first time may use fluoroscopy to ensure adequate positioning of the tibial tunnel or socket. This may help the surgeon create a match between the location of the tip of the curved guide that he or she sees from the posteromedial portal and the fluoroscopic view. Potential advantages and disadvantages of this surgical technique are summarized in Table 3.
Table 3.
Advantages and Disadvantages of Surgical Technique
| Advantages |
| Safe for popliteal neurovascular bundle (anteriorly directed pin and reamer) |
| Avoidance of sharp turn during graft passage—easy graft passage from posterolateral portal |
| Adequate direct visualization of anatomic PCL tibial insertion site |
| No need for intraoperative fluoroscopy |
| Disadvantages |
| Learning curve from working through posterior portals |
| Variability in exit site of pin at anteromedial-proximal tibia |
PCL, posterior cruciate ligament.
The presented technique may have 2 limitations. First, it may be considered that inside-out, antegrade drilling from the tibial footprint increases the risk of causing entrapment of the septum and popliteal neurovascular bundle with the reamer. However, this is unlikely if the reamer is entered by hand under direct visualization and reaming is not started until the tip of the flexible reamer is positioned directly over the footprint. Injury to the popliteal neurovascular bundle is not likely with this technique as compared with a retrograde drilling system.6 Second, there could be a potential risk of neurovascular damage with creating and working through the posterior portals. However, the posterior-posterior triangulation technique has been successfully used in patients.7 The safety of using both the posterior portals for neurovascular structures has been well demonstrated,8, 9 especially with the knee at 90° of flexion.10 Prior studies have shown that the mean distance between the PCL tibial footprint and the popliteal artery is 2 cm (minimum, 1.5 cm) and the mean distance between the posterolateral portal and the common peroneal nerve is 4 cm (minimum, 3 cm).9 The mean distances between the posteromedial portal and the infrapatellar and sartorial branches of the saphenous nerve are 1.5 cm and 2.3 cm, respectively.8
This technical article describes a method to create the tibial tunnel in PCL reconstruction. It has the potential advantages of decreasing the risk of popliteal neurovascular bundle injury (inside-out, anteriorly directed drilling under direct visualization), avoiding a sharp turn during graft passage, and allowing accurate and anatomic tibial tunnel placement without needing the use of intraoperative fluoroscopy.
Footnotes
The authors report the following potential conflict of interest or source of funding: A.P.T. receives support from Tornier. C.T.M. receives support from Headtrainer, Priv IT, Arthrex, Breg, Smith & Nephew, and DJO. D.C.T. receives support DePuy Mitek, Arthrex, Breg, DJO, and Smith & Nephew.
Supplementary Data
Arthroscopic and external view showing the surgical technique of inside-out antegrade tibial tunnel drilling through the posterolateral portal using a flexible reamer for posterior cruciate ligament reconstruction.
References
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Associated Data
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Supplementary Materials
Arthroscopic and external view showing the surgical technique of inside-out antegrade tibial tunnel drilling through the posterolateral portal using a flexible reamer for posterior cruciate ligament reconstruction.