Anatomic Multiple Ligament Reconstructions of the Knee

Abstract

Background:

Multiple ligament injuries of the knee occur in a variety of settings, often from athletic activities. Multiple cruciate and collateral ligament injuries may be associated with hamstring tendon rupture, common peroneal nerve (CPN) injury, meniscus, bone, and cartilage damage.

Indications:

After evaluation for concomitant life-threatening and vascular injuries (especially of the popliteal artery), the knee is assessed through a thorough physical examination and imaging series, including varus, valgus, and posterior stress radiography, and magnetic resonance imaging (MRI). Research over the last 30 years has suggested that operative treatment in the acute setting (<3 weeks) in a single-stage procedure may have improved results to delayed/staged reconstruction. Early range of motion starting on postoperative day 1 is important to prevent development of arthrofibrosis.

Technique:

We describe the technique used to surgically manage a patient suffering from anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and complete posterolateral corner (PLC) rupture. Neurolysis of the CPN is performed to free the irritated nerve from scar tissue, along with biceps femoris tendon and lateral capsular repairs. Anatomic-based reconstructions are performed. The ACL reconstruction is with a single bundle using a patellar tendon autograft, PCL reconstruction is a double bundle with Achilles and tibialis anterior tendon allografts, and PLC reconstruction is accomplished with a split Achilles tendon allograft. The correct orientation of tunnel placement must be planned to avoid tunnel convergence; these angles have been determined through 3D modeling. The optimal sequence for graft tensioning has been established and follows the pattern: PCL, ACL, PLC, and then medial-sided structures if necessary.

Results:

Successful outcomes have been reported for both medial and lateral based injuries, and follow-up studies have also shown equivalent results between acute and chronic outcomes, and for multiligament injuries involving the ACL and PCL if anatomic reconstructions with appropriate tunnel angles, passage and tensioning sequence of grafts, and rehabilitation regimens are performed.

Discussion/Conclusion:

Single-stage anatomic reconstruction is the gold standard for managing multiple ligament injuries in the knee. Commencement of early 0° to 90° knee range of motion and PCL-supporting bracing are critical to prevent arthrofibrosis and protect the grafts from attenuation.

Graphical Abstract

This is a visual representation of the abstract.

VIDEO TRANSCRIPT

Anatomic multiple ligament reconstructions of the knee.

The patient demonstrated in this case is a 24-year-old former athlete who suffered an anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and posterolateral corner injury, which was reconstructed 4 years previously. It was determined that the grafts had failed, and the patient was scheduled for revision surgery.

Many multiple ligament injuries occur in the setting of sports or trauma and carry an associated risk of vascular compromise and associated injuries. Several high-level studies have demonstrated better outcomes with multiple ligament reconstructions in a single-stage operation. Arthroscopically visible anatomic landmarks have been well established for aiding the creation of femoral tunnels using the lateral intercondylar ridge and the bifurcate ridge and the natural overlap between the anterior root of the lateral meniscus and the tibial portion of the ACL can be used to guide the creation of tibial tunnels.

Bone-patellar tendon-bone autografts have been well established for use in single-bundle ACL reconstruction, particularly in the young, active patient. Studies have shown superior knee kinematics and biomechanical function with a double-bundle PCL reconstruction that recreates the footprints of the anterolateral and posteromedial bundles on the femur and insert into a single tibial tunnel midway between the bundle footprints on the PCL facet. An anatomic reconstruction of the posterolateral corner uses a split Achilles tendon allograft to reconstruct the fibular collateral ligament, the popliteus tendon, and the popliteofibular ligament. An anatomic reconstruction of the posterolateral corner will use 2 tunnels replicating the femoral origins of the fibular collateral ligament (FCL) and the popliteus tendon (PLT), one fibular head tunnel is used to recreate the distal FCL insertion and the popliteofibular ligament (PFL) insertion, and one tibial tunnel is used to reconstruct the musculotendinous junction of the popliteus tendon and origin of the popliteofibular ligament.

Assessment of instability of the knee ligaments is done with the Lachman test to assess the ACL, as well as the pivot-shift test for rotational instability, which may suggest underlying pathologies apart from the ACL, the posterior drawer test to assess PCL instability, a valgus stress examination to examine the integrity of the medial collateral ligament (MCL), and a varus stress examination to evaluate the integrity of the FCL and/or the posterolateral corner as a whole.

Objective diagnosis of ligamentous laxity is accomplished with stress x-ray evaluations. The side-to-side difference in opening to valgus or varus stress may be correlated to isolated collateral ligament injuries or broader constellations of injuries. Kneeling posterior stress x-rays are useful in the diagnosis of partial versus complete or combined PCL injuries.

While acute setting single-stage multiple ligament reconstructions are preferred, severe mechanical axis alignment abnormalities may be detrimental to healing. Chronic varus malalignment is not uncommonly associated with long-term posterolateral corner injuries. Coronal plane alignment correction may be first indicated with proximal tibial osteotomy. Magnetic resonance imaging (MRI) evaluation is critical to complete the workup and evaluate for other soft tissue abnormalities or subtle fractures of the tibial plateau or femoral condyles. Patterns of bone bruising visible on MRI may be additionally suggestive of injuries to the posterolateral corner, meniscal roots, or ACL.

The patient demonstrated here was in chronic varus malalignment which required a proximal tibial osteotomy, at which time bone grafting was also performed due to computed tomography (CT) evidence of tunnel osteolysis greater than 12 mm. The patient is positioned supine on the operating table and after examination under anesthesia the footrest is removed to allow for greater mobility of the operative extremity.

Open portions of the procedure are performed prior to arthroscopy to minimize fluid extravasation into the tissues. Posterolateral corner reconstruction tunnels are created first, along with neurolysis of the common peroneal nerve. The patellar tendon autograft is harvested next and then femoral reconstruction tunnels for the PCL and ACL are created arthroscopically, prior to repair of any meniscal pathology. Cruciate ligament tibial tunnels are created next and then a sequence of graft passage and tensioning follows which has been demonstrated by biomechanical studies to better restore the native mechanics of the knee; this follows the order PCL, ACL, posterolateral corner, and then any medial structures if present. Finally, meniscus root or radial tears are secured.

Examination under anesthesia shows a positive Lachman test, dial test, posterior drawer, increased varus gapping to stress, and increased recurvatum. Preparation of allografts should begin well in advance of the case.

A lateral hockey stick incision is made first, and peroneal nerve neurolysis is performed to free the nerve from entrapment in scar tissue. The distal attachment of the FCL is identified on the fibular head, and a 6-mm fibular head tunnel is reamed over a guide pin before a passing stitch is placed. Proximally, the iliotibial band is incised and the attachments of the FCL and popliteus tendon on the femur are identified. Using a collateral ligament guide, a guide pin is drilled through the popliteus tendon attachment at the sulcus, and a ruler is used to place another guide pin 18.5 mm posteriorly to this for the FCL proximal attachment.

Both femoral tunnels are then reamed to a depth of 25 mm with 9 mm reamers, and a passing stitch is placed through each. Through the lateral incision, a tibial guide is used to drill a guide pin from anterior to posterior, just distal and medial to Gerdy tubercle. This tunnel is reamed with a 9 mm reamer. A retractor is placed posteriorly to protect the neurovascular bundle. A passing stitch is then placed. A medial parapatellar incision is then created, and a central third patellar tendon autograft is then harvested, with a 10 mm × 20 mm bone block from the patella and a 10 mm × 25 mm plug from the tibial tubercle.

Medial and lateral arthroscopic portals are created to evaluate the joint, and chondroplasty, lysis of adhesions, and removal of osteophytes are performed as appropriate. Radiofrequency ablation is used to outline and identify footprints of the anterolateral and posteromedial bundles of the PCL.

A 25-mm-deep tunnel for the anterolateral bundle is created with an 11 mm reamer, and a posteromedial bundle tunnel 25 mm deep is created with a 7 mm reamer. These reamers are passed over guide pins which are then used to place passing sutures. A 2-mm bone bridge is maintained between the tunnels. An accessory medial portal is then made, and a bur hole is placed midway between the anteromedial and posterolateral bundle footprints of the ACL. With the knee in maximal flexion, a guide pin is placed, and overreamed to 25 mm with a 10-mm low profile reamer, and a passing stitch is placed through the single femoral ACL tunnel. A posteromedial arthroscopic portal is then created, and the PCL tibial attachment area is cleared with shavers and arthroscopic coagulator. A tibial guide is then used to drill a guide pin to the PCL facet, and its position is verified fluoroscopically. The tunnel is then reamed with a 12-mm reamer using a curette to protect from overpenetration posteriorly.

In the presence of meniscal root tears, transtibial tunnels are created now and 2 simple sutures passed through the meniscal roots and down the tunnels. A large smoothing tool is passed up the tibial PCL tunnel, and, after being used to smooth the tibial PCL tunnel, the smoother is brought out the lateral portal.

The area around the tibial ACL tunnel is then cleared, and a tibial ACL guide is placed. This is used to place a tibial guide pin, which is then overreamed with a 10-mm reamer. Some authors may choose to pass and secure the PCL grafts in the femoral tunnel prior to tibial ACL tunnel creation. The posteromedial bundle graft for the PCL ispassed first, using a guide pin, and secured with a 7mm× 20 mm bioabsorbable screw.

The anterolateral bundle graft is then placed into the femoral tunnel and secured with a 7 mm × 20mm titanium screw passed through a cannula over the guide pin. The passing sutures of the tibial ends of the PCL grafts are then passed through a loop in the smoothing tool, which is then used to pull the PCL grafts down the tibial tunnel. The ACL graft is then pulled up the tibial tunnel using passing sutures into the femoral tunnel and secured with a 7 mm × 20 mm titanium screw.

The popliteus tendon graft and then the FCL graft are pulled into the femoral tunnels and secured with 7 mm × 20 mm titanium screws. The FCL graft is then pulled under the iliotibial band. The anterolateral bundle of the PCL is then secured first with the knee flexed at 90° and an anterior traction force applied, followed by the posteromedial bundle in full extension with cancellous screws and washers.

The ACL graft is then secured in the tibial tunnel with a 9 mm × 20 mm titanium screw. The FCL graft is pulled through the fibular head tunnel and secured in the fibular head with the knee flexed to 20° and a slight valgus reduction force with a 7 mm × 20 mm bioabsorbable screw. The popliteofibular ligament and popliteus tendon grafts are then passed from posterior to anterior through the tibia and secured with a 9 mm × 20 mm bioabsorbable screw. Meniscal root repairs through transtibial tunnels drilled previously may be secured over the anterior tibial cortex now.

Excess graft is trimmed, and closure completes the procedure.

Arthrofibrosis is a common complication of these procedures, and it should be noted that scarring and avulsion of the biceps femoris tendon can make the location of the common peroneal nerve unpredictable. Posterior neurovascular structures are protected by reaming the terminal portions of the tibial PCL tunnels by hand and using a curette to protect from overpenetration. Suture anchors to repair the biceps femoris tendon should be placed at the end of the procedure, and graft preparation should begin well in advance.

Range of motion should achieve 90° within the first 2 weeks with the help of prone passive range of motion. A dynamic PCL brace will be used when swelling resolves. Return to sport is no sooner than 9 months with achievement of strength, symmetry, and adequate scoring on performance testing. Single-stage multiple ligament reconstructions have been shown to improve Tegner, Lysholm, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores at a mean 3½-year follow-up in acute and chronic settings and with PCL- and ACL-based injuries.