Single-Bundle Posterior Cruciate Ligament Reconstruction: Transtibial Technique

Peter David Longino

Robin Martin

Robert J. Giffin

In the past 2 decades, there has been an increase in both basic science research detailing the anatomy and biomechanics of the native posterior cruciate ligament (PCL) and outcome studies evaluating management of the ruptured PCL. While the methodology of the latter continues to improve, results based on the current level of evidence must be interpreted cautiously (18). The focus of many recent studies has been double-bundle versus single-bundle reconstruction techniques. The theoretical advantage goes to double-bundle techniques, but a clinical difference in outcome has not been consistently demonstrated (8,17). Some biomechanical studies have reported improved control of posterior laxity with double-bundle reconstruction; however, results appear to be more dependent on tunnel position and graft tensioning (13).

In acute isolated symptomatic PCL injuries in which the posteromedial bundle and the meniscofemoral ligament remain intact, a single-bundle augmentation procedure may be the preferred surgical technique. In more complex PCL ruptures with associated injuries involving the posterolateral structures (PLS) or medial collateral ligament, more benefit may be derived from double-bundle reconstruction. Again, cadaveric testing of double-bundle PCL reconstruction has not consistently outperformed single-bundle techniques in combined PCL/PLS injury (3). Multi-ligamentous injuries are commonly associated with PCL rupture (15), and their management should be considered carefully in the decision to reconstruct one or both of the functionally distinct PCL bundles. However, the technical complexity of double-bundle reconstruction, the longer surgical time required, as well as the inconclusive clinical outcome are all factors that must be weighed carefully.

INDICATIONS/CONTRAINDICATIONS

The goal of PCL reconstruction regardless of technique is to restore normal knee biomechanics (2) by addressing the various components, the anterolateral and posteromedial bundles and the meniscofemoral ligaments, of the complex anatomy of the PCL. Typical single-bundle reconstruction aims to reproduce the anterolateral bundle of the PCL. In the isolated PCL injury, which occurs much less frequently, absolute indications for surgical treatment include persistent symptoms of knee instability following a Grade III (complete) PCL rupture or a bony PCL avulsion. Contraindications include traumatic knee arthrotomy, active infection, or significant knee stiffness

PREOPERATIVE PLANNING

A complete PCL rupture can be accurately diagnosed by means of a thorough history and physical examination. In light of the known association between PCL rupture and multiligament knee injuries; however, the neurovascular status of the leg must be carefully assessed and documented. Furthermore, careful evaluation of the integrity of the PLS is of paramount importance given the high incidence of associated injury to these structures. Failure to recognize and treat associated PLS instability and/or injury to other secondary restraints will compromise the success of a PCL reconstruction.

Preoperative imaging includes bilateral standing AP radiographs with the knees in both full extension and in 30 degrees of flexion (tunnel view), a lateral radiograph with the knee in 30 degrees of flexion, and a skyline view of the patellofemoral joint. If any clinical or radiographic concerns exist regarding varus or valgus alignment of the lower extremity, three-foot standing views are obtained to determine if a concurrent or staged tibial osteotomy may be required.

Magnetic resonance imaging (MRI) can be helpful prior to PCL reconstruction to identify additional ligamentous injuries. One must keep in mind, however, that while the sensitivity and specificity of MRI in detecting acute PCL rupture have been reported to be 99% and 100% respectively (6,12), the accuracy in the chronic setting is much reduced (16). Associated meniscal injuries occur much less frequently than in ACL rupture (15) and should be managed at the time of arthroscopic PCL reconstruction.

SURGERY

Patients routinely receive one gram of cefazolin intravenously 30 minutes prior to surgery. Those with allergies to cefazolin are given vancomycin or clindamycin.

Patient Positioning

The patient is positioned supine on the operating table. A comprehensive examination under anaesthesia is routinely performed. A tourniquet is applied proximally on the thigh and set at 300 mm Hg and not inflated unless poor visualization secondary to bleeding is encountered. A lateral post is placed at the level of the tourniquet, and a foot rest is used to maintain the knee in a self-supported position of 70 to 80 degrees of flexion (Fig. 34.1). This is the working position for notch preparation, tibial tunnel drilling, and autologous graft harvest. The knee is shaved with electric clippers 5 cm above the proximal pole of the patella to 5 cm distal to the tibial tubercle. Care is taken to incorporate areas of incisions for potential meniscal repairs. Arthroscopy portals are marked, as well as the incision planned for graft harvest and tibial tunnel drilling. The leg is washed and the incision sites are preinjected with 20 mL of 0.25% sensorcaine with 1:200,000 (5 μg/mL) epinephrine. Intraarticular injection is avoided. The leg is prepped with a chlorhexidine solution and allowed to dry before sterile drapes and an iodophor impregnated adhesive drape are applied.

Arthroscopy

Given that no conclusive difference in clinical outcome has been demonstrated in studies comparing tibial inlay techniques to transtibial techniques for tibial fixation (10,14), we currently use an all arthroscopic technique.

Inferomedial and inferolateral parapatellar working portals and a superomedial outflow portal are created vertically with a No. 11 blade. The inferolateral portal is placed slightly more lateral than in routine knee
arthroscopy in order to improve the visualization of the medial femoral condyle when drilling the femoral tunnel. The inferomedial portal is placed medial to the medial border of the patellar tendon and proximal to the medial meniscus. A diagnostic arthroscopy is performed and any meniscal pathology addressed.

FIGURE 34.1 Knee is placed in a self-supported position of 70 to 80 degrees of flexion with a lateral side post. A tourniquet is applied.

Two additional posteromedial portals are created for visualization and preparation of the tibial insertion of the PCL. The safety of posteromedial portals and the value of utilizing dual portals to assist with medial meniscal repair have been well documented (1,11

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