Chapter 57 Posterior Cruciate Ligament Reconstruction

Transtibial Double-Bundle Technique

Posterior cruciate ligament (PCL) surgical reconstruction may be unsuccessful because of failure to recognize and treat associated ligament instabilities (posterolateral instability and posteromedial instability), failure to treat varus osseous malalignment, and incorrect tunnel placement.³²^–³⁴ The keys to successful PCL reconstruction are to identify and treat all pathology, utilize strong graft material, accurately place tunnels in anatomic insertion sites, minimize graft bending, use a mechanical graft tensioning device, use primary and backup graft fixation, and employ the appropriate postoperative rehabilitation program. Adherence to these technical points results in successful single- and double-bundle arthroscopic transtibial tunnel (TTT) PCL reconstruction, documented by stress radiography, arthrometer, knee ligament rating scales, and patient satisfaction measurements.^{7–9,11,13–16,18–25}^,29 The purpose of this chapter is to describe our surgical techniques for arthroscopic TTT PCL reconstruction and posterolateral reconstruction.

The incidence of PCL injury is reported to range from 1% to 40% of acute knee injuries. Incidence is dependent on the patient population reported and is approximately 3% in the general population and 38% in reports from regional trauma centers.^3,^6,¹⁷ Our practice at a regional trauma center has a 38.3% incidence of PCL tears in acute knee injuries, and 56.5% of these PCL injuries occur in multiple-trauma patients. Of these PCL injuries, 45.9% are combined anterior cruciate ligament (ACL)/PCL tears, and 41.2% are PCL/posterolateral corner tears. Only 3% of acute PCL injuries seen in our trauma center are isolated.

This chapter illustrates my surgical technique for the arthroscopic, double-bundle/double–femoral tunnel TTT PCL reconstruction surgical procedure, and presents our results of PCL reconstruction using this surgical technique. Because isolated PCL reconstruction is rarely performed in my practice, this chapter has been written with PCL reconstruction viewed within the context of the multiple ligament–injured knee.

Surgical Indications

Double-bundle/double–femoral tunnel (DB/DFT) TTT PCL reconstruction approximates the anatomy of the PCL by reconstructing the anterolateral and posteromedial bundles of the PCL. This double-bundle reconstruction more closely approximates the broad femoral insertion of the PCL, enhancing the biomechanics of PCL reconstruction.³⁰ Although the DB/DFT TTT PCL reconstruction does not perfectly reproduce the normal PCL, certain components lead to success with this surgical technique:

1 Identify and treat all pathology (especially posterolateral instability).

2 Provide accurate tunnel placement.

3 Identify anatomic graft insertion sites.

4 Use strong graft material.

5 Minimize graft bending.

6 Perform final tensioning at 70 to 90 degrees of knee flexion.

7 Apply graft tensioning.

a Use a mechanical tensioning device.

8 Provide primary and backup fixation.

9 Choose an appropriate rehabilitation program.

Our indications for surgical treatment of acute PCL injuries include insertion site avulsions, tibial step-off decreased by 10 mm or more, and PCL tears combined with other structural injuries. Our indications for surgical treatment of chronic PCL injuries are evident when an isolated PCL tear becomes symptomatic, or when progressive functional instability develops.

Surgical Timing

Surgical timing is dependent upon vascular status, reduction stability, skin condition, systemic injuries, open versus closed knee injury, meniscus and articular surface injuries, other orthopedic injuries, and the collateral/capsular ligaments involved. Certain ACL/PCL/medial collateral ligament (MCL) injuries can be treated with brace treatment of the MCL, followed by arthroscopic combined ACL/PCL reconstruction within 4 to 6 weeks after healing of the MCL. Other cases may require repair or reconstruction of the medial structures and must be assessed on an individual basis.

Combined ACL/PCL/posterolateral injuries are addressed as early as safely possible. ACL/PCL/posterolateral repair–reconstruction performed between 2 and 3 weeks post injury allows sealing of capsular tissues to permit an arthroscopic approach, and still permits primary repair of injured posterolateral structures.

Open multiple-ligament knee injuries/dislocations may require staged procedures. The collateral/capsular structures are repaired after thorough irrigation and débridement, and the combined ACL/PCL reconstruction is performed at a later date, after wound healing has occurred. Care must be taken in all cases of delayed reconstruction to confirm that the tibiofemoral joint is reduced by serial anterior-posterior (AP) and lateral radiographs.

The surgical timing guidelines outlined previously should be considered in the context of the individual patient. Many patients with multiple-ligament injuries of the knee are severely injured multiple-trauma patients with multisystem injuries. Modifiers to the ideal timing protocols outlined earlier include the vascular status of the involved extremity, reduction stability, skin condition, open or closed injury, and other orthopedic and systemic injuries. These additional considerations may cause knee ligament surgery to be performed earlier or later than desired. We have previously reported excellent results with delayed reconstruction in the multiple ligament–injured knee.*

Graft Selection

Our preferred graft source for PCL, ACL, posteromedial, and posterolateral reconstruction is allograft tissue. The anterolateral bundle of the PCL is reconstructed with Achilles tendon allograft, and the posteromedial bundle of the PCL is reconstructed with tibialis anterior allograft tissue. Posterolateral reconstruction is performed with semitendinosus allograft for fibular-based reconstructions combined with a posterolateral capsular shift procedure. Fibular head- and tibia-based posterolateral reconstructions are performed with a split Achilles tendon allograft or a semitendinosus allograft for the fibular arm, and a tibialis anterior allograft for the tibial arm, also combined with a posterolateral capsular shift procedure. Anterior cruciate ligament reconstruction is performed with Achilles tendon allograft or tibialis anterior allograft. Posteromedial reconstruction is performed with a posteromedial capsular shift procedure combined with allograft augmentation as indicated.

Posterior Cruciate Ligament Reconstruction Surgical Technique

The patient is positioned on the operating table in the supine position, and the surgical and nonsurgical knees are examined under general or regional anesthesia. A tourniquet is applied to the operative extremity, and the surgical leg is prepped and draped in a sterile fashion. Allograft tissue is prepared before the surgical procedure is begun, and autograft tissue is harvested before the arthroscopic portion of the procedure is undertaken. Standard arthroscopic knee portals are used. The joint is thoroughly evaluated arthroscopically, and the PCL is evaluated using the three-zone arthroscopic technique.^4,²⁵ The PCL tear is identified, and the residual stump of the PCL is débrided with hand tools and the synovial shaver.

An extracapsular posteromedial safety incision approximately 1.5 to 2.0 cm long is created.^9,^11,^{13–16,18–25}^,29 The crural fascia is incised longitudinally, with precautions taken to protect the neurovascular structures. The interval is developed between the medial head of the gastrocnemius muscle and the posterior capsule of the knee joint, which is anterior. The surgeon’s gloved finger is positioned so that the neurovascular structures are posterior to the finger, and the posterior aspect of the joint capsule is anterior to the surgeon’s finger. This technique enables the surgeon to monitor surgical instruments such as the over-the-top PCL instruments and the PCL/ACL drill guide as they are positioned in the posterior aspect of the knee. The surgeon’s finger in the posteromedial safety incision also confirms accurate placement of the guide wire before tibial tunnel drilling is begun in the medial-lateral and proximal-distal directions (Fig. 57-1). This is the same anatomic surgical interval that is utilized in the tibial inlay posterior approach.

Figure 57-1 The surgeon is able to palpate the posterior aspect of the tibia through the extracapsular extra-articular posteromedial safety incision. This enables the surgeon to accurately position guide wires, create the tibial tunnel, and protect neurovascular structures.

(With permission, Biomet Sports Medicine, Inc., Warsaw, Ind.)

Curved over-the-top PCL instruments are used to elevate the posterior knee joint capsule away from the tibial ridge on the posterior aspect of the tibia. This capsular elevation enhances correct drill guide and tibial tunnel placement (Fig. 57-2).

Figure 57-2 Posterior capsular elevation using Arthrotek Biomet Sports Medicine posterior cruciate ligament (PCL) instruments.

(With permission, Biomet Sports Medicine, Inc., Warsaw, Ind.)

The arm of the Biomet Sports Medicine PCL-ACL drill guide (Biomet Sports Medicine, Warsaw, Ind) is inserted into the knee through the inferior medial patellar portal and is positioned in the PCL fossa on the posterior tibia (Fig. 57-3). The bullet portion of the drill guide contacts the anterior medial aspect of the proximal tibia approximately 1 cm below the tibial tubercle, at a point midway between the tibial crest anteriorly and the posterior medial border of the tibia. This drill guide positioning creates a tibial tunnel that is relatively vertically oriented and has its posterior exit point in the inferior and lateral aspect of the PCL tibial anatomic insertion site. This positioning creates an angle of graft orientation such that the graft will turn two very smooth 45-degree angles on the posterior aspect of the tibia (Fig. 57-4).

Figure 57-3 Posterior cruciate ligament (PCL)–anterior cruciate ligament (ACL) drill guide positioned to place guide wire in preparation for creation of the transtibial PCL tibial tunnel.

(With permission, Biomet Sports Medicine, Inc., Warsaw, Ind.)

Figure 57-4 Drawing demonstrating the desired turning angles that the posterior cruciate ligament (PCL) graft will make after creation of the tibial tunnel.

(With permission, Biomet Sports Medicine, Inc., Warsaw, Ind.)

The tip of the guide in the posterior aspect of the tibia is confirmed with the surgeon’s finger through the extracapsular posteromedial safety incision. Intraoperative AP and lateral x-rays may be used, as well as arthroscopic visualization, to confirm drill guide and guide pin placement. A blunt spade-tipped guide wire is drilled from anterior to posterior, and can be visualized with the arthroscope, in addition to being palpated with the finger in the posteromedial safety incision. We consider placement of the finger in the posteromedial safety incision the most important step for accuracy and safety.

An appropriately sized standard cannulated reamer is used to create the tibial tunnel. The closed curved PCL curette may be positioned to cup the tip of the guide wire. The arthroscope, when positioned in the posteromedial portal, may visualize the guide wire being captured by the curette, and may help in protecting neurovascular structures, in addition to the surgeon’s finger in the posteromedial safety incision. The surgeon’s finger in the posteromedial safety incision is monitoring the position of the guide wire. The standard cannulated drill is advanced to the posterior cortex of the tibia. The drill chuck is then disengaged from the drill, and the tibial tunnel reaming is completed by hand. This gives an additional margin of safety for completion of the tibial tunnel. The tunnel edges are chamfered and rasped with the PCL/ACL system rasp.

The PCL femoral tunnel may be created from outside in or from inside out. When the PCL femoral tunnel is created from outside in, the PCL/ACL drill guide is positioned to create the femoral tunnel. The arm of the guide is introduced through the inferomedial patellar portal and is positioned in such a way that the guide wire will exit through the center of the stump of the anterior lateral bundle of the PCL (Fig. 57-5A and B). The spade-tipped guide wire is drilled through the guide, and just as it begins to emerge through the center of the stump of the PCL anterior lateral bundle, the drill guide is disengaged. Accuracy of placement of the wire is confirmed arthroscopically with probing and visualization. By arthroscopically examining the patellofemoral joint prior to drilling, care is taken to ensure that the patellofemoral joint has not been violated, and that the distance between the femoral tunnel and the medial femoral condyle articular surface is adequate. An appropriately sized standard cannulated reamer is used to create the femoral tunnel. A curette is used to cap the tip of the guide wire, so no inadvertent advancement of the guide wire occurs; this movement may damage the ACL or the articular surface. As the reamer is about to penetrate interiorly, the reamer is disengaged from the drill and the final reaming is completed by hand. This provides an additional margin of safety. The reaming debris is evacuated with a synovial shaver to minimize fat pad inflammatory response with subsequent risk of arthrofibrosis. The tunnel edges are chamfered and rasped.