Combined Ligament Injuries

17 Combined Ligament Injuries

Christopher C. Annunziata, J. Robert Giffin, Christopher D. Harner

Patient Presentation and Symptoms

Combined ligament injuries of the knee typically result from a significant traumatic event. While severe associated injuries can also occur, this chapter focuses on the reconstruction of ligament injuries that occur in the setting of a knee dislocation, which typically results in ruptures of both cruciates as well as injuries to the medial or lateral supporting structures. In the acute setting, patients complain of severe pain and gross instability in the knee and because of this, it may be difficult to obtain an adequate physical examination.

Indications

Controversy still exists with respect to the best form of treatment. In our experience, these patients are at a high risk of persistent and progressive functional instability and pain. Operative treatment, in this setting, has given a predictable outcome without the documented ill effects of immobilization.^1–12 To reproduce the normal kinematics of the knee, both cruciate ligaments should be reconstructed. Associated ligament injuries resulting in grade III laxity have a limited ability to heal in a functional position. Therefore, we recommend the simultaneous repair or reconstruction of all complete ligament ruptures with the goals of restoring knee stability, reestablishing normal range of motion, and returning patients to their preinjury level of function.

Contraindications

In the acute setting, definitive reconstruction may have to be delayed to initially address associated vascular, bone, or skin injuries. Aside from these cases, possible exceptions to operative treatment are older, sedentary individuals, those who may not be able to tolerate extensive surgery or rigorous postoperative physical therapy, and the few who have stable knees after reduction.^13,14

Physical Examination

In the acute setting, motion is limited due to pain but a flexion arc of 0 to 30 degrees is usually obtainable.

Testing of the collateral ligaments can be performed with varus and valgus stresses at both full extension and 30 degrees of flexion. A gentle Lachman’s test will allow for the assessment of anterior cruciate ligament (ACL) integrity. The remaining aspects of the examination require more flexion and, therefore, are best performed with the patient under anesthesia. Anterior drawer and pivot shift testing will complete the assessment of the ACL. The posterior cruciate ligament (PCL) integrity is examined with posterior drawer and Godfrey’s tests, while the posterolateral corner is assessed with external rotation of the tibia at 30 and 90 degrees of knee flexion as well as the reverse pivot shift, external rotation recurvatum, and posterolateral drawer tests.

Diagnostic Tests

Standard radiograph series of the knee consist of an anteroposterior (AP), lateral, and if possible Merchant views. These films should be closely scrutinized for tibiofemoral joint displacement as well as bony avulsion injuries.
Magnetic resonance imaging (MRI) of the knee can evaluate the extent and location of the ligamentous as well as meniscal and chondral injuries.¹⁵ This aids not only in determining which structures need to be fixed but also in predicting what resources will be required.

Special Considerations

The location of the ligamentous tears is important. Primary repairs of cruciate avulsion injuries may do well, whereas primary repair of midsubstance tears has not been successful.^16–18 We therefore reconstruct all midsubstance tears and attempt primary repair of avulsion injuries. With respect to the medial and lateral structures, primary repair is frequently advantageous. Avulsions and intrasubstance tears of the medial collateral ligament (MCL) may be directly repaired. The lateral collateral ligament (LCL) can also be repaired, but we supplement this repair with a graft reconstruction since healing in this location is less consistent than with the MCL, and surgical options are limited should primary repair fail.

Preoperative Planning and Timing of Surgery

The examination and diagnostic imaging studies help to determine which structures need to be surgically treated. For ACL reconstruction we use bone—patellar tendon—bone allograft; for the PCL we utilize Achilles tendon allograft for single-bundle reconstruction with the addition of the ipsilateral autogenous semitendinosus tendon for a double-bundle reconstruction. The LCL is usually repaired and reinforced with an Achilles tendon allograft. Semitendinosus autograft or Achilles tendon allograft can also be used for popliteofibular ligament reconstruction.

The operative intervention of combined ligament injuries should be delayed for 1 to 3 weeks.1,2,4,5,7,8,11,12 This will allow for a return of quadriceps function and restoration of motion that will reduce the risk of postoperative arthrofibrosis.¹⁰ Healing of capsular structures will also take place. An arthroscopic-assisted approach can then be performed, thus minimizing the extent of soft tissue dissection. Beyond 3 weeks, excessive scar formation will frequently limit the ability to adequately identify and repair the medial or lateral structures. It therefore may be prudent to delay surgery until full range of motion is established, after which time late reconstruction can be considered if the patient develops functional instability. In the acute setting, we manage these injuries with combined ACL and single-bundle PCL reconstruction. If surgery has to be delayed beyond the acute period, we have recently added conversion to a double-bundle reconstructive PCL reconstruction. In our experience, a single-bundle PCL reconstruction alone occasionally leaves these patients with residual posterior laxity, especially when they have a feeling of posterior instability in knee flexion and extension.

Special Instruments

30- and 70-degree arthroscopes
Power drill and saw
ACL and PCL tibial and femoral tunnel guides
Standard cannulated and impaction reamers
No. 2 and No. 5 Ethibond sutures (Ethicon, Somerville, NJ)
18-gauge wire
Metal and soft tissue interference screws (Linvatec, Largo, FL)
Endobutton devices (Smith & Nephew Endoscopy, Andover, MA)
Hewson buttons (Richards Medical, Memphis, TN)
AO screws and soft tissue washers (Synthes, Paoli, PA)
G-II anchors (Mitek, Westwood, MA)
Doppler probe

Anesthesia

Options are general anesthesia or epidural block.

Patient and Equipment Positions

Supine
Tourniquet placed high on the leg
Sandbag positioned on the bed to hold the foot such that the knee is at 90 degrees of flexion
Lateral post at the level of the tourniquet
Surgical prep of the entire lower extremity
Doppler probe placed on the field and dorsalis pedis artery marked
Arthroscopic equipment placed on Mayo stand over patient’s abdomen.

Surgical Procedure

We typically begin with arthroscopy and attempt to utilize arthroscopic techniques as much as possible to avoid extensive soft tissue dissection. This is performed with gravity flow in the acute cases to limit the possibility of extravasation of fluid into the posterior knee. In the setting of MCL injury and significant valgus laxity, however, we start with a medial-based incision.^22–24 Our surgical approach to the combined ligament injured knee is to subclassify the injury into bicruciate alone or in combination with a medial or lateral side injury.⁹ Special attention should be paid to planning the incisions. Skin bridges of at least 7 cm must be maintained to avoid potential wound problems.

Medial Side Injury

Make a curved, medial incision from the level of the vastus medialis and continue over the medial epicondyle and extend to the anteromedial proximal tibia just medial to the patellar tendon.^22,23,24
Split the sartorial fascia to gain exposure to the MCL and capsule.
Repair capsular and MCL avulsions primarily with suture anchors, and repair intrasubstance tears with nonabsorbable suture with a modified-Kessler stitch.
Use this incision to harvest hamstring tendons if necessary.

Lateral Side Injury

Following arthroscopic procedures, create a curvilinear incision starting proximally at the lateral epicondyle, paralleling the posterior border of the iliotibial band (ITB) and extending to the midway point between the fibular head and Gerdy’s tubercle.²²
Identify the peroneal nerve proximally, trace it distally, and release it from the fascial adhesions where it enters the anterior compartment.
Develop the interval between the ITB and the biceps femoris, and partially release the ITB from Gerdy’s tubercle. This is easily repaired with suture anchors during closure. Make a longitudinal incision posterior to the LCL to gain access to the lateral capsular and ligamentous structures.
Directly repair avulsions of the LCL and popliteus with suture or suture anchors, and reconstruct interstitial tears.
Reconstruct the LCL with Achilles tendon allograft and reinforce it with the native ligament. Detach it distally and create a 7-mm vertical tunnel in the proximal fibula at the anatomic insertion site. Fix the bone block in the tunnel with an interference screw, and then tension the native LCL proximal and distal to the graft. The soft tissue end of the graft and the LCL are then fixed to the epicondyle with suture anchors.
If the popliteus cannot be primarily repaired, focus attention on reconstructing the popliteofibular ligament. A 7-mm oblique tunnel is created in the proximal fibula corresponding to the native insertion site. A 7 mm × 30 mm blind tunnel is created in the proximal femur at the typical insertion site of the popliteus tendon. A semitendinosus autograft is then fixed in the femoral tunnel with an Endobutton, Hewson button, or soft tissue interference screw. This is followed by looping the graft under the LCL and into the fibular tunnel from posterior to anterior. The graft is then fixed distally while the knee is in 20 to 30 degrees of flexion. The fixation is dependent on whether the LCL was reconstructed and can be performed with the same materials for the femoral fixation, or the graft can be sutured to itself.

Cruciate Reconstruction

Since the principles of ACL and PCL reconstruction are discussed elsewhere, this section focuses on the unique technical aspects and order of bicruciate ligament reconstruction. 1,19,22,23

First, create anatomic placement of the PCL followed by ACL tibial tunnels and confirm their positions with an intraoperative radiograph.
Then, create the femoral tunnels in reverse order, with the ACL followed by the PCL. Depending on which technique is chosen for PCL reconstruction, single or double tunnels are made in the medial femoral condyle.
Perform the medial or lateral repairs as previously described but do not definitively fix them.
Pass the grafts in the usual manner and fix them into the femoral tunnels. The PCL graft is fixed first with either interference or distant fixation techniques. Standard interference fixation of the ACL graft then follows.
For a single-bundle reconstruction, fix the PCL graft in the tibia with a cortical screw and soft tissue washer after the normal anteromedial tibial step-off is re-created with an anterior drawer maneuver and the knee positioned in 90 degrees of flexion. If a double-bundle technique is performed, the semitendinosus graft, reconstructing the posteromedial bundle, is subsequently fixed at 30 degrees of flexion. The ACL graft is then fixed near full extension with an interference screw. 6. Finally, secure the extraarticular repairs or reconstructions.

Dressings, Braces, Splints, and Casts

Place drains in the medial or lateral wounds if needed.
Apply a hinged knee brace locked in extension, paying particular attention to maintaining an anterior drawer on the knee.

Tips and Pearls

The vascular status of the limb must be constantly monitored. Significant vascular injuries can occur; therefore, it is important to frequently assess the distal pulses and tension within the posterior compartment of the leg.
We routinely create an additional posteromedial portal. Through this portal we can pass the 30- or 70-degree arthroscope to aid in visualization, or a shaver to assist in the debridement of the PCL tibial attachment. This can also be performed by creating an anteromedial arthrotomy through the extensile medial approach.
We have found a looped 18-gauge wire to be the most effective means of passing the PCL graft. The wire is passed through the tibial tunnel and into the joint. It is then grasped and taken out the anterolateral portal. The sutures on the end of the graft are then passed through the loop. The portal is lengthened and the graft is easily passed in retrograde fashion by pulling on the distal end of the wire.
Special care should be taken to limit the extent of retraction on the wounds. These incisions can be problematic particularly in the setting of a traumatized knee. If there is any excessive tension, the incisions should be extended.

Pitfalls and Complications

Mistakes can easily be made when creating the ACL tibial tunnel when the PCL is absent. We use the posterior edge of the anterior horn of the lateral meniscus as a reference to the center of the ACL tibial footprint when little of the native footprint remains. The position of the tunnel is also confirmed with an intraoperative lateral radiograph.
Injuries to the lateral structures must be carefully scrutinized. If they are not appreciated and reconstructed, reconstruction of the PCL may fail, or chronic varus or posterolateral instability may develop.
Because of the complexity of the injury, the surgeon must be skilled in the use of various graft sources and several fixation techniques.

Postoperative Care and Rehabilitation

The hinged knee brace is maintained in full extension and ambulation is non—weight bearing with crutches for the first 4 weeks.

Isometric quadriceps exercises are begun immediately and consist of quadriceps sets and straight leg raises. Exercises for the hamstrings, however, are avoided for the first 3 months to protect the PCL reconstruction from posteriorly directed forces.25
Physical therapy is started in the second week and focuses on passive range-of-motion exercises, either in the prone position or with support of the proximal tibia to limit posterior translation.²⁵
Unless the posterolateral structures were reconstructed, the brace is unlocked and weight bearing is advanced after the fourth week. If the posterolateral structures were reconstructed, ambulation is partial for 3 months and then advanced.
Full recovery of motion is slow and may take up to 6 months.