Ralph W. Passarelli, Bradley B. Veazey, Daniel C. Wascher, Andrew J. Veitch, and Robert C. Schenck
DEFINITION
Multiligament knee injuries result from both high-energy (eg, motor vehicle collisions) and low-energy (eg, athletic injuries, falls) events. Dislocation of the tibiofemoral joint is common, with or without spontaneous reduction.
ANATOMY
Put very simply, knee dislocations can be viewed as injuries to one or both cruciate ligaments (ie, anterior cruciate ligament [ACL] or posterior cruciate ligament [PCL]), with variable involvement of the collateral ligaments (ie, the medial collateral ligament [MCL] and the fibular collateral ligament [FCL]) with important musculotendinous stabilizers—the biceps femoris and popliteus posterolaterally, and the pes anserine complex medially, all of which must be considered in restoring knee function. Palpable bony landmarks about the knee are crucial to aid in orientation for examination and when planning subsequent surgical approaches.
The lateral femoral epicondyle and the fibular head are critical to identify the placement of lateral incisions, as are anatomic structures such as the FCL and peroneal nerve. Medially, the femoral epicondyle, tibial tubercle, pes insertion site, and posteromedial tibial edge are crucial landmarks for medial surgical exposures for inlay and MCL reconstruction.
The intrinsic structure of the vascular system of the knee consists of an anastomotic ring of five geniculates: the superomedial, superolateral, inferomedial, inferolateral, and middle geniculates, as well as muscular and articular branches.
The extrinsic system plays a crucial role when parallel medial or lateral incisions are made about the knee in the sagittal plane.
Proper planning should allow 7 to 10 cm between superficial parallel incisions to greatly lessen the risk of skin bridge loss, but it has been our experience that such incisions should be avoided if possible. This network alone cannot support vascularity distal to the knee with popliteal vessel occlusion.
The surgical anatomy of the knee usually is described in layers, going from the superficial structures to the deep structures.
Layer I is commonly described as consisting of Marshall's layer (arciform) anteriorly, the sartorius medially, and the iliotibial band and biceps femoris fascia laterally.
Layer II includes the FCL, patellar tendon, and superficial MCL.
Layer III includes the posterior oblique, arcuate ligament, and deep portion of the MCL. Layer III is thin anteriorly and has distinct, structurally important thickenings posteromedially (posterior oblique ligament) and posterolaterally (arcuate ligament). A Segond fracture is caused by avulsion of the thickened middle third of the lateral knee capsule in this layer.
Posterolateral reconstructions are complex because of this anatomy and variability and require restoration of both the FCL and popliteofibular (PFL) ligaments.
The surgeon should understand the important anatomic relationships of the posterior structures of the knee, especially in regard to the popliteal neurovascular bundle.
The medial and lateral heads of the gastrocnemius are the borders of the popliteal fossa distally, the pes anserinus tendons medially, and the biceps femoris tendon laterally. The popliteus, posterior joint capsule, oblique popliteal ligament, and posterior femoral cortex form the floor of the fossa. Through this fossa run the plantaris muscle and the neurovascular structures. The popliteal artery enters through the adductor magnus superiorly as it leaves Hunter's canal, courses through the fossa, and exits through the soleal arch. The popliteal vein enters superolateral to the artery and continues superficial to the artery, but is located deep to the tibial and common peroneal nerves, leaving the fossa medial to the popliteal artery.
The vascular structures are located directly behind the posterior horns of the medial and lateral menisci. The vascular structures are protected during posteromedial and posterolateral approaches if the surgeon remains anterior to the medial and lateral heads of the gastrocnemius during dissection and careful retraction; of course, further dissection towards the midline can injure the bundle with either approach.
With the advent of posterior procedures to the tibial side of the PCL, it is critical to understand the posterior neurovascular anatomy. The posteromedial approach also is useful to gain access to the tibial insertion of the PCL.
Deep dissection along the posterior tibial surface and femoral condyles provides additional safety for this approach. Use of a tourniquet during dissection provides improved visualization of the surgical planes.
Unlike the vascular surgeon, who uses a posteromedial approach for the neurovascular (popliteal) bundle, the orthopedic surgeon dissecting posteromedially should avoid the neurovascular bundle. Staying anterior to the medial gastrocnemius and hugging the posterior aspect of the knee joint protects the bundle in the orthopedic approach.
It is important to stop the dissection at the PCL, because further dissection laterally with this approach eventually will reach and potentially injure the bundle.
NATURAL HISTORY
Before the development of modern surgical techniques for management of multiligament injuries, scores of patients were left with stiff, unstable, or even amputated limbs. Today, even with aggressive evaluation and treatment, patients ultimately may have residual instability with a lower level of activity, decreased range of motion (ROM), and even amputation. The use of allografts in multiligament-injured knees is a recent advance, although occasionally it is complicated by deep infection.
PATIENT HISTORY AND PHYSICAL FINDINGS
During the initial evaluation of a patient with a suspected multiligament knee injury, the clinician should be cognizant of the potential for concomitant injuries. Highor low-energy knee trauma can have potentially lifeor limb-threatening injuries, which must be identified acutely.
Once any life-threatening injuries have been treated, careful examination of the injured limb focuses both above and below the knee to evaluate for fracture as well as continuity of the extensor mechanism.
A careful injury history should be obtained if possible, including pre-hospital neurovascular status of the limb, time of injury, and mechanism. Patients often relate a history of hyperextension of the knee in sporting events or a flexed knee that struck the dashboard during a motor vehicle accident.
Any evidence of current dislocation of the tibiofemoral joint should be addressed emergently, with attempted reduction under sedation, splinting, careful neurovascular examination preand post-reduction, and high-quality radiographic evaluation following reduction.
The radiographic evaluation should include an anteroposterior and lateral radiographs of the knee with the limb in a long-leg splint to demonstrate that a successful reduction has been achieved.
Any asymmetry in the vascular examination from the uninjured extremity, even pre-hospital, necessitates further evaluation, with the specifics often dictated by vascular surgery protocols and regional preference.24
Many clinicians routinely obtain angiograms regardless of the vascular examination findings with multiligament injured knees.2 Nonetheless, the current trend toward using sequential clinical examinations in the reduceddislocation with normal pulses is becoming more popular and is considered safe.
Use of Doppler or other noninvasive vascular laboratory studies in conjunction with an ankle brachial index is very useful, because these studies can provide objective information (rather than the subjective findings of pulses), and also avoids the invasiveness of angiography.
The surgeon must be aggressive in the management of any abnormal vascular findings, with immediate vascular consultation and immediate surgical exploration of ischemia in the reduced knee dislocation. Ischemia in the dislocated knee requires reduction and pulse or vascularity reevaluation. Continued ischemia for more than 6 to 8 hours results in amputation rates of up to 80%.10
Medial puckering of the soft tissues of the knee usually suggests a posterolateral dislocation with buttonholing of the medial femoral condyle through the joint capsule, MCL incarceration into the joint, and irreducibility with closed methods of reduction.7,28
IMAGING AND OTHER DIAGNOSTIC STUDIES
An integral part of evaluation of the multiligamentously injured knee is plain radiographs before and after reduction to confirm congruity of the joint, evaluate for associated fractures, and detect ligament avulsion injuries that may aid in timing of the treatment plan.
MRI is an excellent adjunct to delineation of the extent of injury and pattern of ligament injury and musculotendinous and osteoarticular injuries. These studies are combined with a careful examination of the ligamentous structures with and without anesthesia, which are compared to the uninjured extremity.
MRI cannot replace a careful clinical examination under anesthesia, which can determine ligament function and the need for ligament reconstruction.
CLASSIFICATION
Multiple classification systems have been used to describe dislocations of the knee.
Historically, the most commonly used system has been based on a positional description of the relationship of the femur on the tibia when the knee is dislocated.9 However, this system is not without problems.
First, most knee dislocations present spontaneously reduced, making classification based on position at the time of injury difficult, if not impossible.
Second, this system does not provide information regarding the energy of the injury, the ligaments injured, or associated neurovascular injuries, all of which play a part in the overall treatment plan.
Classifying dislocations based on the anatomic injury pattern (ie, ligaments torn and associated neurovascular injuries) allows for adequate physician communication (especially for future reconstructions) and preoperative planning.3 The anatomic classification is shown in Table 1.
DIFFERENTIAL DIAGNOSIS
Knee dislocations can be difficult to assess in the presence of gross knee swelling or with the presentation of multi-trauma.
Accurate detection of associated neurovascular injuries is critical.
Identification of the ligaments injured is based on the initial examination, imaging studies, and examination under anesthesia.
NONOPERATIVE MANAGEMENT
Many patients today are treated with surgical management of some type; however, depending on their injury pattern,there are still subsets that are treated nonoperatively. These include patients with severe comorbidities that increase the risks of surgery or those with open dislocations or greatly damaged soft tissue envelopes, where the focus is on restoring the envelope and treating infection.
Cast Immobilization
Although cast immobilization technique was used for many years to treat multiligament injuries to the knee before modern reconstructive procedures were available, closed treatment as definitive management rarely is indicated.
Immobilization in extension for 6 weeks, as described by Taylor,26 can result in a stable knee, but in our experience should be used only in circumstances where the preferred technique of ligamentous reconstruction is not applicable or feasible.
External Fixation
External fixation may be used to span the knee joint with fixation in the tibia and femur, and is useful in patients who have poor rehabilitation potential. It also may be used as a temporary stabilizing measure in open knee dislocations, severe soft tissue injuries, and vascular reconstructions while awaiting optimal conditions for operative ligamentous reconstructions.
Advantages include adequate maintenance of reduction, access to soft tissue wounds, and protection of maturing reverse saphenous vein grafts.
However, the potentials for loss of knee motion and exuberant scar formation (arthrofibrosis) exist, and these often require later manipulation under anesthesia and lysis of adhesions.
Hinged Knee Brace
The patient is placed in a hinged knee brace, and supervised ROM exercises are initiated in the first few weeks following the injury.
This treatment method is ineffective in creating a stable knee but is an extremely important step in the process to a successful multiligamentous reconstruction.
Gaining extension, a more normal gait pattern, full flexion, and decreased swelling (resolution of inflammation) add to an easier postoperative course, with avoidance of postoperative stiffness and heterotopic ossification with multiligamentous reconstruction. In our experience, early multiligamentous reconstruction has tremendous risks for stiffness and a poor result.
The work of Shelbourne21 and others with ACL/MCL injuries with preoperative rehabilitation is even more applicable to multiligament knee injuries. Obtaining preoperative ROM before PCL, ACL, and collateral ligament reconstruction is extremely useful in obtaining a stable, pain-free knee after dislocation.
SURGICAL MANAGEMENT
Indications
Operative reconstruction is recommended to most patients with multiligament knee injuries. In some cases, an external fixator is used temporarily followed by surgical reconstruction; in most cases, early braced knee motion is instituted with delay of reconstruction of ligament injuries undertaken only once motion is restored and inflammation is resolved.
Ligamentous repair (ie, suture repair) is less and less commonly used, because the results are variable, and the use of early postoperative ROM, in our experience, results in failure of the suture repair.
Crucial to the immediate care of these injuries is a meticulous neurovascular examination. Any vascular deficit necessitates emergent vascular surgery consultation and consideration for an open popliteal artery exploration and reverse saphenous vein graft reconstruction.
Patients with open injuries, popliteal artery reconstructions, severe soft tissue injuries, or complex injury patterns (concomitant fractures) should be considered for external fixation for 2 to 4 weeks to allow healing of the soft tissue envelope and maturation of the arterial repair or reconstruction. Once conditions have been optimized and wounds are healed without infection, reconstruction can be performed.
The optimal timing for surgical intervention is not clearly defined, although many investigators recommend waiting for several weeks after the injury before performing surgical repair or reconstruction of these multiligamentous injuries. The operating surgeon must have a good working knowledge of ligamentous reconstructions and should proceed according to his or her level of experience and preference.
In our experiences, it is best to wait for preoperative motion, gait, and swelling to improve. Over 15 years of experience with knee dislocations has led to the following guidelines:
Delayed reconstruction is better than immediate surgery.
Preoperative rehabilitation is useful to regain motion, and resolution of swelling and inflammation is critical to surgical success.
Reconstruction is done with alloand autografts, avoiding surgical repairs.
Both cruciates and involved collateral(s) are reconstructed simultaneously.
Approach
Graft Choice
Many graft choices are available for ACL reconstruction in the multiligament-injured knee. We prefer a bone–patellar tendon–bone (BTB) allograft.
While a BTB autograft is the gold standard in an isolated ACL reconstruction, the comorbidities of ipsilateral graft harvest in combined ACL-PCL injuries can result in stiffness, especially in simultaneous cruciate reconstruction.
The ipsilateral hamstring autograft should not be considered in a type III knee dislocation (KDIIIM) injury, because the hamstrings provide a secondary restraint to valgus load and may be required for MCL reconstruction.
Allografts are ideal for the multiligamentous knee injury.
Posterior Cruciate Ligament Reconstruction
A number of approaches to modern PCL reconstruction are available, including (1) transtibial and femoral tunnels (with or without dual femoral socket) and (2) tibial inlay using a single or dual femoral tunnel in which tibial fixation is achieved by securing a bone plug into a trough positioned at the anatomic insertion of the PCL.
The inlay technique places the bone–tendon junction of the graft at the joint line of the proximal tibia and may avoid the risk of the “killer curve” graft impingement seen experimentally with the transtibial tunnel technique.
One of the senior authors prefers a dual femoral socket (ie, double-bundle femoral) and tibial inlay PCL reconstruction through a posteromedial approach.
The Achilles tendon allograft is ideal for such a reconstruction. The calcaneal bone plug is fashioned for the tibial inlay, and the tendon portion is split into 6and 8-mm graft bundles for posteromedial and anterolateral PCL bundle reconstruction, respectively. Cannulated, fully threaded 4.0-mm screws are used for the tibial inlay fixation, and soft tissue interference and biodegradable screw fixation (7and 9-mm) are used in double-bundle femoral fixation.
PCL reconstructions often have failed to reestablish normal posterior translation at long-term follow-up.
Authors have proposed that two major factors are responsible for late loosening and resultant residual posterior tibial translation following this surgical method.
The first factor is the acute angle the graft must make to round the posterior lip of the tibia when exiting the transtibial tunnel. This has been described as the “killer turn” or “killer curve,” which may cause graft abrasion and subsequent failure.11 A biomechanical study reported an increased failure rate of transtibial over tibial inlay technique (32% transtibial, 0% inlay) following cyclic testing. Significant differences also were reported in graft thinning and elongation between the two techniques, favoring the inlay technique. The inlay grafts demonstrated 13% thinning and 5.9 mm of graft elongation over 2000 cycles, compared with 41% thinning and 9.8 mm of graft elongation with the transtibial technique.13
The second factor involves the distinct anatomic bundles of the PCL, which function at different degrees of knee flexion.4 Reconstructing the specific PCL bundles may produce more normal function than the single femoral tunnel technique (anterolateral PCL bundle).
Clinically, long-term cadaveric studies are needed to fully verify these biomechanical differences. Clinical studies to this point have shown no difference in outcome between transtibial and inlay techniques.11
The double-bundle technique allows reconstruction of both the anterolateral and posteromedial bundles of the PCL.
Although tibial inlay techniques may appear cumbersome, advances have been made that reduce the technical difficulties encountered during this procedure.
We believe the posteromedial approach to PCL reconstruction described here simplifies this technique by maintaining the patient in the supine position during ACL and PCL reconstruction, avoiding the prone position altogether, preserving the origin of the medial head of the gastrocnemius, and simplifying graft passage.
TECHNIQUES
BONE–PATELLAR TENDON GRAFT FOR BONE–ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION
The patient is positioned supine with a lateral post or leg holder in place.
Standard arthroscopy portals are used, and a systematic examination of the knee is performed.
Tibial and femoral tunnels 10 to 11 mm in diameter are drilled using standard methods.
The allograft BTB bone plugs for the ACL are fashioned to match the tunnel diameter, and the femoral plug is fashioned to a length of 25 mm.
A small drill is used to place a hole in the femoral bone plug of the graft and a no. 2 braided composite suture (Fiberwire, Arthrex, Naples, FL) is passed through the hole for graft passage.
Two holes are drilled in the tibial bone plug and a no. 2 suture is passed to aid in graft passage, and even potential post or staple fixation in case of graft length mismatch.
A critical step in planning the depth of the femoral tunnel is factoring in the length of the allograft.
The femoral tunnel should be drilled to a length of30 to 35 mm.
Most patients require an intra-articular graft length of 25 mm.
Sixty millimeters (35 mm for the femoral tunnel plus 25 mm for the intra-articular portion) should be subtracted from the length of the entire graft to yield the ideal tibial tunnel length.
This method ensures that optimal fixation of the bone plug in the tibial tunnel will be possible.
A guide pin is placed endoscopically through the tibial tunnel into the femoral ACL origin and drilled out the anterolateral cortex of the femur and through the skin.
A no. 2 braided composite suture from the femoral bone plug is placed through the eyelet of the guide pin.
The guide pin and suture are pulled up into the femoral ACL socket, passing into the femoral tunnel.
Fixation on the femoral side is performed using an interference screw through the inferomedial portal with a protective sleeve.
Fixation and tensioning of the tibial side of the ACL graft are delayed until after PCL reconstruction.
At this point, the PCL dual femoral socket sites are selected and drilled (discussed later in this section).
Sutures are placed in the PCL femoral tunnels to allow graft passage.
Once the PCL graft is securely fixed, then, and only then, is the ACL allograft tensioned in full extension and secured to the tibial tunnel using a metal interference screw.
If graft tunnel mismatch occurs and the ACL tibial bone plug is not completely within the tibial tunnel, tibial interference fixation can be performed with an oversized soft tissue biodegradable interference screw, or staple–post fixation can be performed externally on the tibial surface.
In our experience, simultaneous bicruciate reconstruction, although complex, can be simplified by the following steps, performed in this order:
ACL femoral and tibial tunnel preparation; dual femoral PCL tunnel preparation; ACL graft passage with fixation of the femoral side only; tibial inlay via the posteromedial approach; PCL graft passage and fixation; ACL tibial fixation; and, lastly, collateral reconstruction as indicated.
Such steps allow for the most time-efficient process for simultaneous cruciate reconstruction.
DOUBLE-BUNDLE POSTERIOR CRUCIATE LIGAMENT RECONSTRUCTION
Positioning and Preparation
The patient is positioned supine on the operating table with the use of a lateral post. A careful examination under anesthesia is performed to confirm the ligament injury and diagnosis.
Standard inferomedial and inferolateral arthroscopy portals are used.
A 30-degree arthroscope is inserted and diagnostic arthroscopy performed to confirm the PCL tear.
The PCL remnant is removed and the anatomic origin identified.
Double-Bundle Tunnel Preparation
A long drill-tip guidewire is placed through the inferolateral portal with the knee positioned at 90 degrees, viewing the pin placement from an inferomedial portal. This allows sequential femoral bundle pin placement and reaming for the anterolateral bundle of the PCL (8-mm tunnel) followed by posteromedial tunnel creation (6 mm).
The guidewire is inserted in the anatomic site of the anterolateral bundle (usually high in the notch, near the articular surface), drilled into the condyle and exiting out of the skin overlying the distal medial thigh.
The slotted end of the guidewire is used to pass a suture into the tunnel, with the loop remaining in the tunnel.
At our institution, both tunnels are reamed endoscopically through the medial cortex to allow for adequate graft tensioning.
At this point, both femoral sockets have been reamed, passing sutures are in place (exiting the inferomedial portal), and the posteromedial approach is performed.
Posteromedial Approach and Tibial Inlay Site Preparation
All arthroscopic instruments are removed from the knee, and the leg is placed in the figure 4 position.
The primary surgeon is positioned on the contralateral side of the operating table with the assistant on the ipsilateral side of the injured knee.
The leg is exsanguinated, and the tourniquet is inflated with the knee hyperflexed.
A posteromedial approach to the knee is utilized, with a 6to 10-cm incision centered over the posterior joint line. The incision should follow the posterior cortex of the proximal tibia and the medial femoral epicondyle.
The sartorius fascia is exposed and incised in line with the skin incision. The gracilis and semitendinosus tendons are retracted posteriorly and distally. The fascia between the medial head of the gastrocnemius muscle and the posterior border of the semimembranosus muscle is divided in line with the incision. The semimembranosus muscle is then dissected off of its tibial insertion and tagged with a nonabsorbable suture for later repair.
The remainder of the exposure is performed by blunt dissection following the posterior border of the joint line and remaining anterior to the medial head of the gastrocnemius muscle at all times to protect the popliteal neurovascular structures.
The popliteus muscle is elevated, and a blunt Hohmann retractor is placed just lateral to the PCL insertion onto the tibia. This provides excellent visualization of the posterior tibia to create the trough.
The remnant of the PCL, the posterolateral edge of the medial femoral condyle, the joint surface, and the lateral meniscus are palpable anatomic landmarks that are used to position the trough in the center of the posterior tibia.
A burr is used to cut a trough 10 mm wide × 10 mm deep × 25 mm long extending from the joint line and centered over the midline, posterior tibia.
The trough should correspond to the size and shape of the allograft bone block.
The trough should not be placed too distally, because such placement could possibly create the killer curve effect on the graft.
A posterior capsulotomy is made at the mid-joint line, and a curved Kelly clamp or similar arthroscopic instrument is used to perform the posterior capsulotomy, through the notch medial to the ACL graft and through the inferolateral portal.
The dual socket passing sutures are transferred out the back of the knee into the posteromedial exposure.
We routinely use dry arthroscopy to ensure that the sutures are on the correct side of the ACL as well as to aid in grasping the sutures when reaching from the posterior approach.
At this time, the tourniquet is released and hemostasis is evaluated. Release of the tourniquet often is indicated at this stage, especially if it was inflated prior to making the posteromedial approach, during notchplasty, ACL tunnel fixation, graft passage, and PCL dual socket formation.
Graft Preparation
As noted earlier, our preferred graft for PCL reconstruction is an Achilles tendon allograft.
This graft allows for either a singleor double-bundle femoral technique, depending on surgeon preference and experience.
The graft can easily be fashioned into a double-bundle graft.
The ends are prepared by placing a traction stitch with a no. 2 Fiberwire suture to facilitate graft tubulization and eventual passage.
The calcaneal bone plug is fashioned to maintain the double-bundle tendons and can vary in size (often, it is 15 mm wide × 15 mm deep × 35 mm long). Hence, graft preparation must be performed before tibial trough creation.
Tibial Graft Passage and Fixation
The tibial inlay graft is positioned into the tibial trough with care taken to ensure that the bone–tendon junction is positioned at the joint line.
The tibial side of the graft is fixed first to ensure that the bone–tendon junction is positioned at the joint line to avoid graft abrasion.
The inlay is secured with two 4.0-mm cannulated screws over a guidewire, positioned 1 cm apart.
The screws are placed from posterior to anterior and parallel to the joint line.
It is critical to aim the screws anterolaterally in the tibia to avoid inadvertent fixation of the ACL graft.
Femoral Graft Fixation
Once the inlay is secured, the double-bundle graft ends are sequentially passed.
In our experience, the posteromedial bundle is passed first and fixed prior to the anterolateral bundle.
If both grafts are passed simultaneously, visualization for the posteromedial bundle is obstructed by the anterolateral bundle.
As noted, we routinely use a 6 mm graft size for the posteromedial bundle with placement of a 7-mm × 30-mm soft tissue biodegradeable interference screw.
The knee is positioned at 20 degrees of flexion during tensioning, and the screw is placed endoscopically with viewing from the inferomedial portal.
Next the anterolateral bundle is passed (8-mm graft) and fixed with a 9-mm × 30-mm soft tissue interference screw.
The knee is ranged through 20 cycles before the anterolateral bundle is fixed, with the knee positioned at 70 degrees of flexion.
Lastly, the tibial side of the ACL allograft reconstruction is identified and ranged. The ACL graft is fixed with the knee in full extension.
Collateral Reconstruction
At this point, the ACL and PCL reconstructions are complete, and the associated collateral reconstruction is performed.
Although it is tempting to delay the collateral reconstruction, it is the senior author's opinion that the bicruciate reconstruction is at risk for failure or loosening by staging the collateral reconstruction.
We try to limit the number of other procedures scheduled the day of a bicruciate reconstruction to minimize the pressure from those other cases that may tempt the surgeon to delay the collateral reconstruction (TECH FIG 1).
TECH FIG 1 • AP and lateral views of a left knee that has undergone a posterior cruciate ligament (PCL) revision reconstruction (notice retained titanium interference in the medial femoral condyle [MFC]) using tibial inlay technique for the tibial side of the graft and dual femoral tunnel reconstruction with soft tissue interference screws on the femoral side. Staples visible medially are from a simultaneous MCL reconstruction with anterior tibialis allograft.
SINGLE-LOOP POSTEROMEDIAL COMPLEX RECONSTRUCTION
An incision is made from the medial femoral epicondyle to the posterior aspect of the insertion of the pes anserinus tendon on the tibia. The sartorius fascia is incised in line with the semitendinosus tendon from distal to proximal, and graft harvest is performed, leaving the tibial attachment in place.
The proximal end of the semitendinosus is cleared of remaining muscle, and a Krackow suture is placed in its free end.
A subretinacular tunnel is made from distal to proximal, and the graft is passed using this approach.
Using a high-speed burr, a U-shaped trough is made around the isometric point of the medial epicondyle.
The graft is laid into this trough and stapled into place.
The graft is passed back through the fascial tunnel, and the knee is cycled through a ROM.
The graft is then stapled to the tibia at the insertion of the MCL.
After wound closure, the limb is placed in a sterile bulky dressing with medial and lateral plaster slabs for 7 to 10 days.
We monitor these patients carefully and progress them slowly through ROM.
MODIFIED TWO-TAILED RECONSTRUCTION OF THE POSTEROLATERAL CORNER
The key components of the deep posterolateral corner are the popliteus, the PFL, and the FCL. The modified two-tailed reconstruction16 addresses each of these components.
The patient is positioned supine on the operating table, with the injured extremity draped free. The leg is carefully positioned on the operative table, with the foot resting in the seated surgeon's lap.
The knee is flexed to 90 degrees to relax the peroneal nerve, and a skin incision is made beginning at the lateral epicondyle of the femur toward the fibular head.
The iliotibial band is incised in line with the fibers from Gerdy's tubercle, extending proximally to the supracondylar process of the femur.
At this point, the peroneal nerve is identified as it courses from the biceps femoris through the perineural fat to the fibular neck.
In our experience, the nerve is identified most easily at the level of the joint line, where it can be palpated. However, depending on the specific injury and the presence of inflammation, the nerve may be identified along the fibular neck or even as it crosses the lateral gastrocnemius head.
It is critical to identify the nerve first before any ligamentous exploration or reconstruction is performed.
Neurolysis is performed distally through the length of the incision. The nerve is protected with a small vessel loop.
Once the nerve is exposed and protected, the FCL and the posterolateral structures are identified through blunt dissection. The surgeon should not dissect posterior to the lateral gastrocnemius muscle, because this places the popliteal neurovascular structures at risk.
Once the exposure is complete, a 5-mm tunnel is drilled from anterior to posterior on the lateral tibia, exiting where the popliteus tendon traverses the back of the tibia.
A retractor is placed posteriorly during the drilling to protect the neurovascular structures.
The tibial tunnel is tapped with a 7-mm tap to allow fixation with a bioabsorbable interference screw.
A tibialis tendon allograft is fashioned to approximately 5 mm and passed into the tunnel from posterior to anterior.
The allograft tendon must be at least 24 cm long to allow reconstruction of all three components.
The graft is secured in the tibial tunnel with a 7-mm bioabsorbable interference screw from anterior to posterior.
A second 5-mm tunnel is made in the fibular head from anterolateral to posteromedial, but is not tapped.
The isometric point on the lateral femoral condyle is located by finding the intersection of the FCL and the popliteus tendon.
Using a 3.2-mm drill bit, a hole is made in the lateral femoral condyle at the isometric point from lateral to medial to allow placement of a 4.5-mm bicortical screw.
If a concomitant ACL reconstruction is performed, this hole must be drilled from posterior to anterior to avoid interfering with the femoral tunnel of the ACL graft.
An osteotome is used to decorticate the bone around the screw to allow healing of the allograft to bone. A spiked soft tissue washer is used with the screw.
The graft is then passed from the posterior aspect of the tibia to the anterior portion of the screw and then posteriorly around to the fibular tunnel.
The popliteofibular portion of the graft should lie deep to the popliteus portion of the graft.
The graft is then passed from posterior to anterior through the fibular tunnel and back to the screw and washer.
The graft is tensioned with the foot internally rotated and the knee flexed 40 to 60 degrees.
The screw and washer are then secured to the lateral femoral condyle and graft.
This completes the reconstruction of all three posterolateral components described earlier. If there is an injury to the PLC, early repair should be considered.
MULTILIGAMENT RECONSTRUCTIONS
Knee Dislocation Type I: Anterior Cruciate and Collateral Ligaments Torn
The integrity of the ACL determines the timing of reconstruction for a type I knee dislocation.
ACL reconstruction is best delayed until ROM is restored, for two reasons:
Collateral ligament healing usually occurs nonoperatively.
Postoperative stiffness often is avoided.
We prefer to regain complete ROM and delay reconstruction for this type of injury. Patients usually regain knee motion within 6 weeks of the injury.
Graft choice is based on surgeon experience and patient preference and usually involves an ipsilateral bone–tendon–bone autograft.
Collateral ligament injury associated with only one torn cruciate ligament usually can be treated nonoperatively.
Knee Dislocation Type II: Anterior and Posterior Cruciate Ligaments Torn
The integrity of the collateral ligaments allows for early ROM and a delayed reconstruction of the cruciate ligaments.
We prefer allografts for cruciate reconstructions performed simultaneously, but the decision is based on surgeon experience, patient preference, and risk tolerance.
Our graft of choice for bicruciate injuries is BTB allograft for the ACL and an Achilles tendon allograft for the PCL (dual-bundle femoral with inlay tibial bone plug).
The patient is positioned supine with the injured extremity draped free. A post is used to assist with arthroscopy.
Diagnostic arthroscopy is performed through standard portals, and associated injuries are treated as required.
The remnants of the cruciate ligaments are débrided, and a notchplasty is performed to allow for adequate visualization of ACL femoral tunnel placement and graft passage.
The detailed technique for ACL and PCL reconstructions is described earlier in this chapter.
The ACL tibial and femoral tunnels are prepared first, and the guide pin advanced into the femoral tunnel to be used later for graft passage. The femoral tunnel may be drilled under dry visualization.
The PCL femoral tunnel(s), either double-socket (preferred) or single, are prepared next under dry visualization. The guide pin is advanced into the femoral tunnel and the attached suture brought through the inferomedial portal for later graft passage.
The ACL BTB allograft is passed from the tibial tunnel to the femoral tunnel and secured endoscopically to the femur with the knee hyperflexed. The tibial side of the graft is not fixed until after the PCL fixation is complete.
Arthroscopic instrumentation is removed from the knee and the extremity positioned in the figure 4 position.
The posteromedial approach is used to gain access to the tibial attachment of the PCL.
The tibial trough is fashioned as previously described.
A Kelly clamp or selected arthroscopic instrument is passed from the posterior capsulotomy through the notch medial to the ACL graft to grasp sutures entering the PCL femoral tunnels.
The sutures are passed to the back of the knee through the capsulotomy.
The tibial bone plug of the PCL graft is placed in the trough and secured to the tibia using two 4.0-mm cannulated screws. Care must be taken to avoid placement of screws in the ACL tibial tunnel.
The PCL graft is tensioned through the femoral side, and the knee is put through its ROM 20 times.
The PCL femoral side is fixed endoscopically sequentially with the knee positioned at 20 degrees (posteromedial bundle) of knee flexion and then at 70 degrees (anterolateral bundle).
Fixing the PCL graft before final ACL tensioning avoids posterior subluxation of the tibia on the femur.
The ACL graft is fixed to the tibial side with the knee in extension.
Again, the ACL must be tensioned after the PCL fixation. Performing ACL tension and fixation before PCL reconstruction could create posterior subluxation of the tibia on the femur.
Knee Dislocation Type IIIM: Tears of the ACL, PCL, and MCL
The steps for addressing a combined bicruciate injury with a collateral injury are similar to those described for the bicruciate reconstruction through double-bundle passage into the dual femoral sockets.
During the posteromedial approach, the MCL is exposed as described earlier.
After double-bundle passage into the dual femoral sockets, the MCL loop graft is tensioned and secured to the femur and the tibia.
The tibial side of the ACL graft is then tensioned in extension and secured to the tibia.
Knee Dislocation Type IIIL: Torn Anterior and Posterior Cruciate Ligaments and Lateral Complex
As for the Type IIIM reconstruction, the reconstruction of a Type IIIL injury proceeds through double-bundle passage into the dual femoral sockets.
After the PCL is tensioned, the lateral approach to the knee is performed, and the FCL and posterolateral corner reconstructed using the technique described earlier.
The ACL graft is then tensioned in extension and secured to the tibia.
Knee Dislocation Type IV: Torn ACL, PCL, MCL, and Lateral Complex
This pattern most often is associated with a high-energy injury and represents a complex reconstruction.
Careful attention to knee position during tensioning of the grafts is required to achieve a stable and concentric reconstruction in which the tibiofemoral joint is not subluxed.
The initial reconstruction follows bicruciate ligament reconstruction through double-bundle passage into the dual femoral sockets, including exposure of the MCL.
A lateral approach is used to expose the posterolateral corner, as described earlier.
The MCL and PLC are prepared.
The MCL graft is tensioned and fixed.
The posterolateral graft is tensioned and fixed.
The ACL graft is tensioned in extension and fixed to the tibia.
POSTOPERATIVE MANAGEMENT
A thorough understanding of the reconstruction and tailoring the treatment plan to each individual patient are crucial to all rehabilitation protocols.
Patients who undergo early repair or reconstruction of multiligament knee injuries should begin supervised knee motion exercises within the first 3 days after surgery to decrease the risk of arthrofibrosis.
A hinged knee brace is used after bicruciate reconstructions, with non–weight bearing of the extremity recommended for 3 to 4 weeks.
Weight bearing is progressed to full, usually at 6 weeks, with a brace and crutches.
With medial or lateral procedures consideration is given for a slower return to full weight bearing owing to poor quadriceps tone and potential unfavorable mechanics.
Early postoperative therapy focuses on control of edema and pain to facilitate return of quadriceps function.
Following PCL reconstruction, early return of full extension is paramount.
Supervised passive extension exercises are performed with a simultaneous, anteriorly directed force on the proximal tibia twice daily.23
The knee is kept in a postoperative brace from 0 to 90 degrees for the first 6 weeks.
Closed kinetic chain active exercises are allowed in this arc of motion.
The goal is to regain full ROM by 3 months.
If 90 degrees of flexion is not achieved by 6 to 12 weeks, manipulation under anesthesia (MUA) is strongly recommended.2,15
Straight-line jogging usually is begun at 5 to 6 months, depending on quadriceps function.
Patients may return to full activity in 9 to 12 months.
OUTCOMES
The trend in recent years of increased surgical management of ligamentous injuries, coupled with earlier motion and a more aggressive approach to the management of stiffness (eg, MUA, arthroscopic lysis of adhesions), has yielded more favorable results than those previously reported regarding function, pain, and the incidence of debilitating instability.
Studies using Lysholm scores for outcomes favor surgical treatment of these injuries over nonoperative treatment, with an average increase of 20 points reported with operative intervention.12,18,20,23,25,31
Generally speaking, 93% of patients are able to return to some type of occupation, but may not be able to work at a highly demanding job. In seven studies, approximately 70% of patients returned to their previous occupation. 12,14,17,19,20,25,27
With surgical intervention, many patients ultimately have knees that function well for activities of daily living, and some are able to participate in recreational sports, but only 40% are able to return to their previous level of activity.17,20,22
COMPLICATIONS
One of the most devastating problems encountered in multiligament knee injuries is failure to identify and appropriately manage vascular injuries in the acute phase.
Another common problem is failure to recognize the full extent of the ligamentous injury, including capsular disruption at the time of surgical management.
There also is potential for nerve injury, with peroneal nerve involvement more common than tibial nerve injury.
Complete nerve dysfunction carries a much worse prognosis than a partial injury, especially regarding the tibial nerve. Fewer than half of these patients have complete functional recovery of the nerve.5,6,8
The necessity of creating multiple femoral and tibial tunnels brings with it the potential risk of tibial plateau fracture, medial femoral condyle avascular necrosis, and subchondral fracture.
The potential also exists for intraoperative neurovascular injury, especially with lateral side reconstructions (peroneal nerve) and PCL reconstructions (popliteal neurovascular bundle).
Postoperatively, the risks include infection (especially with open injuries), wound healing problems with multiple incisions, and arthrofibrosis (with or without heterotopic ossification).
On average, 38% of multiligament knee injuries require at least one surgical intervention to regain motion. 14,15,17,19,22,25,27,30
There also is concern for posttraumatic arthritis (especially of the patellofemoral joint), potential loss of graft or repair fixation, and deep venous thrombosis with pulmonary embolus.
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