Multiligament Injuries

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Multiligament Injurie

Matthew S. Shapiro

Severe knee injuries that damage multiple ligaments are among the worst extremity injuries that orthopaedists encounter. They are fairly unusual, and their relative rarity makes them uncomfortable for many doctors to treat because of a lack of familiarity. Because most orthopaedists treat only a few of these injuries in a career, it is difficult to establish a personal protocol based on experience. There are multiple recommendations in the literature about treatment for these injuries but unfortunately no consensus. The threat of limb loss or catastrophic outcome adds to the difficulty in treating patients with these injuries.

Dislocated knees may present with the tibiofemoral relationship intact or distorted. Many knee dislocations either self-reduce or are reduced by athletic trainers, emergency medical technicians, or emergency physicians prior to evaluation by an orthopaedist. If gross instability is present, or if there is evidence of bicruciate injury [anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) ruptures], the knee should be considered to have been dislocated and be treated as such.¹

Initial evaluation of these patients is often done in conjunction with a trauma team. Knee dislocations that occur in the setting of a motor vehicle accident are often called high-velocity injuries, as opposed to those that occur in the setting of sports, which are typically called low-velocity injuries. This nomenclature can be somewhat artificial, however, and low-velocity injuries can have more soft tissue disruption than the high-velocity injuries. The difficulty in the multiple trauma patient is often coordinating care around multiple other sites of injury, and with multiple physician consultants.

The first priority in evaluating these patients is confirming adequate circulation to the extremity. Vascular injury is common with knee dislocation, occurring in up to 43% of cases.² Intact distal pulses do not rule out the presence of a vascular injury, particularly an intimal flap tear. The danger of such an injury is delayed occlusion, which can occur 24 to 72 hours after injury. Because there is poor collateral circulation around the knee, a popliteal vessel injury can be catastrophic, frequently leading to amputation. All patients with a knee dislocation are at risk for such an injury, and some type of vascular evaluation is required. Controversy exists as to how best to do this, with some preferring angiography in all cases, and others recommending serial vascular examinations for the first several days. Noninvasive vascular studies, such as brachial/ankle indices, have also been proposed, but there is no solid evidence that they are as effective as arteriography. In a review of several previous studies, Armstrong and Franklin² found that 34% of patients with knee dislocation had injury to the popliteal artery, but about one third of those patients had normal distal pulses. The authors reported three studies where a patient with normal pulses eventually required surgery for occlusion.

If a patient presents with absent pulses after a suspected knee dislocation, a true vascular emergency exists. Consultation with a vascular surgeon is required, and emergency revascularization a priority. Conventional angiography in this setting is generally not recommended, as it is unnecessarily time-consuming. On-table angiography in the operating room (OR) is a better option. Bypass grafting, often with a reversed saphenous vein, is the most common solution. In this situation, early surgical intervention to stabilize the knee is recommended (see discussion later in chapter).

Nerve injury is also common, especially so in the setting of vascular injury. The common peroneal nerve is most commonly injured, especially with a varus injury, but the tibial nerve is also at risk. Traction injury with transient neurapraxia occurs most often, but more serious injury, with axonotmesis, and even complete avulsion injuries also occur. Often, the treating physician is advising the patient without direct knowledge of the condition of the nerve, and prognosis is often based on guesswork. Direct inspection of the nerve is often helpful and should be done whenever lateral repair or reconstruction is performed. Complete nerve transection is catastrophic, and reconstructive techniques, such as cable grafting, have limited benefit.

Surgical Indications and Other Options

Surgical decision making in patients who have sustained a knee dislocation is complex. Many layers of decisions are required, including patient selection, the timing and staging of surgery, and technique and graft choice. The combinations and permutations of each individual injury make it difficult to come up with a single surgical plan that works universally. Treatment must be individualized, but general principles apply.

Patient Selection

Decades ago, many patients with knee dislocations were treated nonoperatively, often with immobilization, sometimes with transarticular pinning. The results were almost always a disappointment, with stiffness and dysfunction the rule. As surgical procedures for ligament reconstruction became available, most orthopaedists elected to treat these injuries with surgery, but techniques were widely varied, with little uniformity in strategy or outcome. The most recent studies describe a more uniform approach, with more favorable outcomes, and most authors recommend reconstructive treatment for knee dislocations.

There are selected patients, however, who may be candidates for nonoperative treatment. A study by Jari and Shelbourne 3 described a protocol for the nonoperative treatment of selected patients after knee dislocation. The authors pointed out the fact that the PCL, unlike the ACL, has a limited potential to spontaneously heal, as does the medial collateral ligament (MCL). Complications of early surgical intervention include arthrofibrosis, and the authors feel that delayed surgery for ACL-PCL-MCL-injured knees is more appropriate. Initial treatment for these patients is immobilization at 20 degrees and weight bearing as tolerated for 1 to 2 weeks. As the MCL heals, the patient is transitioned to a hinged knee brace for an additional 2 to 4 weeks. Once the MCL has healed, a delayed PCL reconstruction (PCLR) is done for patients who have PCL laxity greater than 2+ and increased recurvatum. If there is only slight PCL laxity, surgery is not recommended. Following recovery, either with PCLR or nonoperative treatment, ACL reconstruction is done in a staged fashion for patients who continue to have symptomatic anterior instability. Results from this approach have not yet been published.

Other experts disagree. Prohaska and Harner⁴ stated that primary repair of the MCL becomes extremely difficult longer than 3 weeks after injury. Their approach is early surgical intervention, with repair or reconstruction of all injured structures. Nonoperative treatment is not recommended for patients who are reasonable surgical candidates.

Timing and Staging of Surgery

As noted previously, a difference of opinion exists about when to perform surgery on patients with multiple ligament injuries. Most knee dislocations can be reduced and held in reasonable alignment with an immobilizer or hinged knee brace. Occasionally, profound instability exists, and early intervention is required to stabilize the knee. Some surgeons have resorted to application of a temporary external fixator. This can lead to excessive knee stiffness, and pin tracts can complicate later reconstruction. In selected cases early surgical intervention is appropriate. The decision then is how much of the problem to correct. One option, as endorsed by Harner, is to repair or reconstruct all injured structures at a single sitting. This may be difficult or impossible if stabilization is required immediately (for instance, if a vascular repair is performed at the time of injury). Early surgery may instead take the form of repair of extraarticular structures only, with staged surgery to reconstruct the cruciate ligaments. Other injuries, such as avulsed menisci and ruptured patellar tendons, are attended to at this time. This is an especially good approach if other injuries require that the patient be taken to the OR immediately, and a full reconstruction cannot be adequately planned or performed. An early rehabilitation program with the knee in a hinged brace is instituted, and delayed reconstruction of the cruciates is done.

Surgical Techniques

A variety of surgical techniques may be employed for the treatment of the dislocated knee, with no clear consensus about which is best. All injured structures require repair. For collateral ligament injuries and posterolateral corner injuries, this is generally accomplished via early direct repair. Meniscal injuries, extensor mechanism injuries, and PCL avulsions are also best treated with direct and early repair. Repair of cruciate ligaments has fallen out of favor, and reconstructive techniques are universally applied. Standard intraarticular ACL reconstruction is appropriate, with surgical decision making required to determine graft choice and timing of surgery. Patellar tendon (PT), quadriceps tendon (QT), or hamstring auto-grafts, sometimes from the contralateral knee, or patellar, tibialis, or Achilles’ tendon allografts are the available choices. The reconstruction may be done within the first few weeks, in conjunction with extraarticular repairs, or done in a staged fashion when the knee is less stiff and swollen. Delay of primary repair of extraarticular structures beyond 2 to 3 weeks may eliminate the chance of an ideal outcome, as the tissues deteriorate and become impossible to directly repair. PCLR can also be done early or late, with or without concomitant surgery, and with a variety of graft choices. Furthermore, PCLR can be done with single or multiple stranded grafts, and via intraarticular or onlay techniques. Again, there is no consensus regarding the best approach.

My preference is to perform a limited early procedure. When circumstances require (e.g., in association with a vascular injury), this may be done immediately. Otherwise it is done within the first 2 to 3 weeks after injury. Examination under anesthesia and a low-pressure, limited arthroscopy are done to identify and catalogue all the injured structures. Meniscal repair, if necessary, can be done via an arthroscopic or open approach. Extensor mechanism injuries and PCL avulsions are repaired directly. Collateral structures are evaluated, and if necessary, treated with direct repair. Most commonly, this is accomplished by direct reattachment to bone with spiked washers and screws, although the surgeon needs to use whatever resources are available, including suture-anchors and direct suturing if necessary. Interstitial ligament rupture is more difficult to repair, but may heal favorably with bracing and early motion.

Several years ago, the author treated a collegiate football player who had dislocated his knee during a scrimmage. He sustained a varus mechanism injury and a posterolateral dislocation. His knee was reduced while he was still on the field, and he was taken to the OR for treatment within the first 24 hours. Every lateral structure in his knee was torn, with one exception: the lateral collateral ligament was avulsed from the fibula, the iliotibial band was avulsed from Gerdy’s tubercle, the lateral hamstrings were avulsed from the posterior tibia, the posterolateral corner was avulsed from the tibia, and the popliteus muscle belly was avulsed from the posterior tibia; remarkably, the only lateral structure in continuity was the peroneal nerve. Early intervention for this patient was to directly repair all of the injured structures. (This patient also underwent simultaneous open ACL and PCL reconstructions. His excellent outcome was remarkable.)

After initial extraarticular surgery, an early rehabilitation program should be started. This may involve continuous passive motion (CPM) if the stability of the knee is satisfactory, and if early motion will not jeopardize associated vascular repair. When swelling and pain subside, and when suitable range of motion (ROM) is restored (0 to 120 degrees), a delayed reconstruction is done. Most commonly this occurs 4 to 6 weeks after the initial procedure, but can be delayed further if necessary. ACL and PCL reconstructions are performed using a whole patellar tendon allograft, which the author splits into two hemigrafts. A standard arthroscopic-assisted ACL procedure is preferred, in combination with a PCL onlay.

If medial, lateral, or posterolateral laxity persists, delayed reconstruction is recommended. Again, this can be done by a variety of techniques and with a variety of graft materials. The author’s preference is to use Achilles’ tendon allograft, with the bone block fixed with an interference screw in the isometric point of either the medial or lateral femoral condyles; the graft is then used to reconstruct the MCL, or the fibular collateral ligament and the popliteal-fibular ligament.

Tips and Tricks

The most conclusive assessment of soft tissue damage can be obtained by a careful physical examination. In the author’s experience, this can best be done with the patient under anesthesia in the OR. A priority, therefore, is to get the patient to the OR within the first 2 weeks after injury. Magnetic resonance imaging (MRI) should be obtained prior to this, but most operative decision making is based on the examination under anesthesia rather than on the MRI.

As mentioned above, circumstances may require that the patient be taken to the OR immediately, such as other life-threatening injuries, associated open fractures, or concomitant vascular injuries. This is an opportunity to assess the injured knee and to begin treatment. A relatively simple and short procedure can often dramatically improve the stability of the knee, and in some cases may stabilize the knee sufficiently that future surgery is not required. In any event, early stabilization facilitates immediate rehabilitation.

It is important to adequately inform the patient about the severity of these injuries. The surgeon should tell patients several things right away: they will likely need multiple surgeries; recovery may take a year or more; the goal of treatment is a stable and pain-free knee that will be capable of activities of daily living and occupational activities; recreational activities are a possibility, but the prognosis for return to competitive athletics is guarded. With this in mind, it is entirely logical for the surgeon to plan on staged surgery. Trying to accomplish too much in a single surgical procedure can unnecessarily complicate things; it can increase anesthetic and surgical times, increase the risk of complications such as arthrofibrosis (AF) and infection, and preclude the use of a tourniquet. Staged surgery is rational, and in fact preferred in many of these cases.

Rehabilitation decisions may be complex as well. Associated injuries may preclude early motion, CPM, weight bearing, and aggressive therapy. Even when isolated injuries are considered, rehabilitation issues can be complicated. Rehabilitation decisions must be individualized, but some broad principles apply. These procedures are much more complicated than a standard ACL surgery; aggressive treatment is not beneficial. It should be explained to patients at the beginning that recovery will be slow and extremely conservative. The author believes that a stiff, stable knee is preferable to one that is flexible and unstable; therefore, the postoperative program is designed primarily to avoid graft injury and/or stretching. I do not allow unresisted flexion or extension exercises, preferring all closed-chain, co-contraction exercises. With the idea that PCL reconstructions tend to stretch out more commonly than ACL reconstructions, it is recommended that many of the postoperative exercises be done in the prone position, in an effort to minimize the effect of gravity on the PCL graft. I keep patients in a locking extension brace for 4 to 6 weeks after reconstructive surgery, allowing them only brief periods of ROM activities. Patients are encouraged to stay on crutches for 4 to 6 weeks, although limited weight bearing is permitted. Running and agility exercises are not permitted for 6 months, and return to limited sports is not expected for a full year. This is, perhaps, unnecessarily restrictive, but again, the priority should be to protect the grafts and avoid residual instability.

Pitfalls and How to Avoid Them

The two major problems associated with knee dislocation are stiffness and residual instability. Performing major reconstructive procedures early, when the knee is stiff, swollen, and painful, may increase the likelihood of developing AF, much as it does with isolated ACL rupture. A staged or delayed reconstructive approach may diminish the chance of AF. Alternatively, a second minor procedure (arthroscopic lysis of adhesions and manipulation) may resolve AF when initial surgery is more complex and results in stiffness.

Residual instability is more difficult to prevent. Ideal graft position may be compromised by abnormal tibiofemoral relationships. Great care must be taken intraoperatively to place tunnels in their proper locations, often using landmarks that are different from those used in simpler procedures. Some of the usual landmarks may be gone, and tibiofemoral relationships are different, thus precluding isometry testing. Confirmative intraoperative fluoroscopy may be beneficial to some surgeons who don’t perform these procedures frequently. Adequate graft material must be used, and with multiple injuries, sufficient autograft may not be available. There may be a tendency to use marginally sufficient grafts in some situations, particularly if the patient is not willing to accept the risks of allograft use. Contralateral autograft should be considered in an effort to diminish further injury to an already-traumatized knee.

When multiple structures are injured, and multiple reconstructive procedures contemplated, great care must be taken to ensure that the hardware from one reconstruction does not interfere with hardware, tunnel, or graft from another. Detailed preoperative planning and the use of templates may help to avoid this problem. Creativity and flexibility are required: what a surgeon may do for an isolated ligament injury often has to be changed significantly when reconstructing multiple structures.

Conclusion

Knee dislocations present with a high degree of variability: from low to high energy, with and without associated injuries, and with a variable amount of soft tissue injury. More than with other orthopaedic injuries, the surgeon must individualize the patient, the injury, the treatment, and the recovery, and be enormously flexible in approach. Currently, the outcome after a knee dislocation is guarded, but with the orthopaedic community focused on this problem, continued improvement in results should occur.

References

1 Wascher DC, Dvirnak PC, DeCoster TA. Knee dislocation: initial assessment and implication for treatment. J Orthop Trauma 1997;11:525–529

2 Armstrong PJ, Franklin DP. Management of arterial and venous injuries in the dislocated knee. Sports Med Arthrosc Rev 2001;9:219–226

3 Jari S, Shelbourne KD. Nonoperative or delayed surgical treatment of combined cruciate ligaments and medial side knee injuries. Sports Med Arthrosc Rev 2001;9:185–192

4 Prohaska DJ, Harner CD. Surgical treatment of acute and chronic anterior and posterior cruciate ligament medial side injuries of the knee. Sports Med Arthrosc Rev 2001;9:193–198

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