Recognition to Rehabilitation: Treating Traumatic Knee Injuries

ABSTRACT: Knee dislocations are injuries that present infrequently, yet have the potential for devastating outcomes if not managed appropriately. Due to the anatomical arrangement of the knee, true knee dislocations are invariably associated with multiligamentous injuries. With the various neurovascular structures in close proximity to the knee joint, these injuries also have the potential for significant neurovascular impairment. This article discusses the appropriate recognition, evaluation, management, and rehabilitation of multiligamentous knee injuries based on available literature to improve overall patient outcomes when managing dislocations of the knee joint.

Classically, a knee dislocation has been defined as the disarticulation of the tibial and femoral surfaces supported by radiologic evidence.^1-4 More recently, the definition has been broadened to include any multiligamentous injury affecting at least 2 of the 4 major knee ligaments—anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), mild medial collateral ligament (MCL), lateral collateral ligament (LCL)—that results in multidirectional instability of the knee.^1,3,4 This newer and more comprehensive definition is believed to more accurately diagnose knee dislocations by also incorporating those injuries that have likely spontaneously reduced prior to radiologic examination.⁴

True dislocations of the knee joint are exceedingly rare, yet they are considered to be one of the most detrimental insults that can occur to the knee joint. These injuries represent a genuine emergency that has the potential to be limb-threatening.^1,5,6-8 Knee dislocations account for less than 0.2% of all documented orthopedic injuries.⁸ Some studies have reported rates of true knee dislocations to be between 0.001% and 0.013% per year, even at the busiest medical centers.⁹ An analysis of 2 million patient admissions at the Mayo Clinic between 1911 and 1960 found that only 14 cases were associated with knee dislocations.¹⁰ That said, it is widely speculated that knee dislocations are underestimated due to the fact that many of these injuries spontaneously reduce prior to proper evaluation and diagnosis.^1,4,6,7 

This article discusses the appropriate recognition, evaluation, management, and rehabilitation of multiligamentous knee injuries to improve overall patient outcomes when managing dislocations of the knee joint.

Anatomical Review

The 4 main ligaments that comprise the knee joint work in conjunction with numerous muscles and tendons to stabilize the knee. The ACL and PCL are the principal stabilizers of the knee joint, and are responsible for maintaining the knee in the anterior and posterior planes, respectively.^2,6,9,11 The ACL has also been documented as a key structure in preventing excessive external rotation of the tibia on the femur and inhibiting deviant hyperextension of the knee.¹² The MCL functions to resist valgus force applied to the knee, while the LCL acts in opposition to varus force.^2,6,11 The medial and lateral menisci aid in the cushioning and distribution of axial load, while also providing rotational stability.^2,6

The popliteal artery and its distal branches supply blood flow to the lower extremity. The popliteal artery is a continuation of the femoral artery, which navigates across the popliteal fossa, giving rise to genicular arteries, the anterior tibial artery, and the posterior tibial artery. Proximally, the popliteal artery is firmly attached to the femur at the adductor hiatus. Distally, the popliteal artery is securely fastened to the tibia by the fibrous arch of soleus muscle.^6,12,13 

Due to these anatomical attachments, the popliteal artery is at tremendous risk for injury during knee trauma; various studies have estimated that the prevalence of vascular injury in association with knee dislocations can range from 16% to 64%.^8,14 A multi-study review by Green et al¹³ found that 43% of anterior knee dislocations were accompanied by vascular injury, while 56% of posterior knee dislocations were affiliated with vascular injury. Kennedy et al¹⁵ noted that anterior knee dislocations are more often associated with hyperextension, which is likely to cause a stretch injury to the popliteal artery, which results in intimal vascular damage. 

Posterior knee dislocations, on the other hand, are more liable to yield a complete rupture of the popliteal artery as the posterior rim of the tibial plateau directly traumatizes the popliteal artery.^12,13,15,16 Although collateral blood supply is offered by the genicular arteries, they are not sufficient to meet the demands of the lower extremity once the popliteal artery has been compromised.^12,13,17 With meager collateral blood supply, an injury to the popliteal artery threatens the vascular stability of the lower extremity and is ultimately associated with a high rate of morbidity. The necessity for a below-the-knee amputation can be as high as 86% in patients who do not have sufficient blood flow restored within 8 hours of sustaining the injury. However, if blood flow is restored within 8 hours, 89% of the limbs remained viable and did not require an amputation.^4,5,8,16  

The common peroneal nerve (CPN) is one of the main neurologic contributors to the lower extremity. It originates where the sciatic nerve divides into the common peroneal and tibial nerves. As the CPN travels distally, it runs obliquely through the popliteal space toward the fibular neck. As the CPN approaches the peroneus longus muscle, it divides into the deep and superficial peroneal branches.¹⁸ The deep peroneal nerve and its subsequent branches serve to innervate a portion of peroneus longus, tibialis anterior, extensor digitorum longus, extensor hallucis longus, peroneus tertius (also known as fibularis tertius), extensor digitorum brevis, and extensor hallucis brevis muscles. The superficial peroneal nerve and its successive branches lend innervation to the peroneus longus and peroneus brevis muscles in addition to supplying cutaneous sensory innervation to the anterolateral lower leg and dorsum of the foot.¹⁸

Due to its fixed attachment near the neck of the fibula, the CPN is particularly susceptible to traction and contusion injuries.^19,20 The fixed attachment of the CPN leaves the proximal portion of the nerve vulnerable to injury when hyperextension, varus, or rotational forces are applied to the knee.¹⁹ Various studies have reported CPN injuries in 14% to 40% of individuals with knee dislocations, with the majority of studies citing an incidence between 25% and 35%. The greatest risk for CPN injury occurs when extreme varus or rotational forces are applied to the knee and results in a traction-type injury.² In a study of 84 cases of sports-related CPN injuries by Cho et al,¹⁸ skiing and football were correlated with the highest incidence of neurologic injury at 50% and 27%, respectively.

Mechanism of Injury

A multiligamentous injury to the knee significantly impairs the stability of the joint, leading to the potential for critical damage to the knee joint and to vital structures in immediate proximity to that region. The majority of patients who present with knee dislocations have experienced a high-velocity impact, with motor vehicle accidents being the most implicated mechanism of injury.^1,2,6,7,20 High-velocity injuries are associated with forceful trauma, which puts the patient at higher risks for sustaining neurovascular injury and subsequent complications during recovery.⁶ On the other hand, the majority of athletic-related injuries and work-related injuries are considered low-velocity injuries (eg, falling at work, being tackled by an opponent on the football field, or receiving a hip check in ice hockey). Of late, there has been an increase in both low- and high-velocity knee dislocations, which may be attributable to an increase in the speed, size, and strength that current athletes possess in addition to an upsurge in the interest and participation in extreme sports (eg, snowboarding, ski jumping, and sky diving).^1,2,20

Knee dislocations can be subdivided into acute or chronic injuries. A knee dislocation is considered to be acute when the patient has had the injury for less than 3 weeks. When the injury has been present for longer than 3 weeks, it is deemed to be chronic.⁸ Traditionally, knee dislocations have been anatomically characterized using a directional system based on the tibiofemoral relationship (Table). This system, initially proposed by Kennedy et al,¹⁵ classifies knee dislocations as anterior, posterior, lateral, medial, or rotatory. While the directional system remains useful today, it has been criticized due to its deficiency in describing specific patterns of ligamentous disruption. A more modern classification system describes knee dislocations based on certain patterns of ligamentous injury and concomitant intra-articular fractures. This contemporary classification system imparts greater clarity regarding the likely biomechanics of the trauma, severity of the injury, and optimal course of treatment.^21-23 

Anterior knee dislocations are the most commonly documented directional dislocation, accounting for 40% of cases.²⁴ Anterior knee dislocations are typically associated with forced hyperextension, and are generally seen in sports in which direct blows to the anterior knee are common (eg, soccer).^1,2,6,8 Kennedy et al¹⁵ were able to produce anterior knee dislocations in cadavers by employing a stress machine to replicate forced hyperextension. From these studies, it was determined that the posterior capsule and the popliteal artery were compromised at nearly 30º of hyperextension and at 50º of hyperextension, respectively.^1,9,11,12 Spontaneous anterior knee dislocations have also been reported in increasing numbers in patients who are morbidly obese. These may occur as an individual stands from a seated position due to the added burden placed on the joint.^2,7 

Posterior knee dislocations account for approximately 33% of all knee dislocations.²⁵ These injuries are often associated with posterior force applied to the tibia with the knee in a flexed position, thereby forcing the tibia in a posterior position and out of articular alignment with the femur. This type of injury is commonly linked to individuals involved in dashboard impacts in motor vehicle accidents.^1,2,6,8 

Lateral knee dislocations are estimated to comprise 18% of knee dislocations and are produced by valgus stress. In contrast, medial knee dislocations are generated when varus stress is applied to the knee joint and account for 4% of knee dislocations.^2,8,25

By definition, all types of knee dislocations are associated with multiligamentous injury, but the specific patterns of ligament damage can vary greatly. It is fairly uncommon to induce injury to all 4 major knee ligaments—occurring in only 11% of all knee dislocations. Bicruciate injury with accompanying disruption of the MCL (41%) and bicruciate injury with posterolateral corner disruption (28%) are documented as the most common injuries associated with knee dislocations.⁸ Studies have shown that the MCL, an extra-articular ligament, has an inherent ability to heal when the torn ends of the ligament are within close proximity to one another. Conversely, the ACL and PCL are intracapsular structures, which are not apt to mending without surgical intervention.⁹

A Case Study

A 40-year-old female patient presented with reports of severe right knee pain after being involved in a traumatic collision with another athlete during an intramural soccer match. The patient described experiencing a direct blow to her right lower extremity when an opposing player fell onto her and exerted blunt posterior force on her lower leg. As she fell, her upper body rotated while her right foot remained firmly rooted to the playing field. After the collision, the patient immediately experienced excruciating pain in her right knee and perceived a gross deformity of her right lower extremity. No attempts were made to bear weight on her injured limb at the time of injury. She was quickly transported to the nearest hospital.

Laboratory tests. Anteroposterior and cross-table lateral radiographs of the patient’s right knee were obtained. They demonstrated a complete anterior tibiofemoral (knee) dislocation with associated rotatory dislocation (Figure 1) and overlap of the medial femoral condyles with the tibial plateau and a valgus deformity of the knee (Figure 2). Further, the patella was significantly tilted posteriorly and was displaced (Figure 1). Postreduction anteroposterior and cross-table lateral films were later obtained and showed interval reduction of the tibiofemoral dislocation into anatomical alignment without residual valgus deformity. The patella had also returned to anatomical alignment (Figures 3 and 4).  

An MRI of the right knee was performed, showing a complete ACL tear (Figure 5). An avulsion was noted at the PCL insertion on the posterior tibial plateau with a possible partial injury to the PCL more proximally (Figure 6). An avulsion of the proximal aspect of the fibular collateral ligament from the lateral aspect of the lateral femoral condyle, MCL and medial retinacular sprains, partial muscle injuries of the distal biceps femoris and the proximal aspects of both medial and lateral gastrocnemius, a mild partial injury of the biceps tendon insertion on the fibula, a posterior capsule tear, and a partial injury at the popliteus muscle-tendon junction were also noted on the MRI. 

Diagnosis. The patient was diagnosed with an anterior tibiofemoral dislocation, which was subsequently reduced in the emergency department. It was determined that she was neurovascularly intact. 

Treatment. She was discharged home with outpatient orthopedic follow-up after a sufficient observational period. The patient was placed in an immobilizing right knee brace for 2 weeks post-injury to allow the capsular tear to heal. After considerable discussion regarding the significance of her injury, the indication for surgical repair, possible operative and postoperative complications, and the necessity of compliance with postoperative physical therapy and prescribed medications, the patient underwent multiple ligament reconstruction surgery. ACL, PCL, and posterolateral corner reconstructions were performed to restore right knee stability, with favorable outcomes.

Standard Evaluation

In the instance of severe blunt trauma to the knee joint, the lower extremity should be splinted and the patient should be transported to the nearest emergency department for proper evaluation and treatment.⁶ Given that most knee dislocations occur following violent trauma, such as motor vehicle accidents, all initial measures should be directed toward maintaining the patient’s airway, breathing, and circulation. Primary assessment using Advanced Trauma Life Support protocols and appropriate resuscitation efforts should take precedence in the initial treatment of any trauma patient.⁷ After the patient has been stabilized, attention can then be given to specific injuries.

A knee dislocation should be considered in any patient who presents with gross knee instability, even if the knee is in proper anatomical alignment on initial evaluation.²⁰ Visual inspection of the knee can provide valuable information as to the extent of the patient’s injury. While a grossly deformed lower extremity can be self-evident of a multiligamentous injury to the knee, the medical team should be vigilant for other observable signs of knee dislocation, especially in a knee that does not appear grossly distorted. For instance, marked bruising and swelling of the lateral or medial knee is suggestive of an uncontained hemarthrosis as a result of major capsular disruption.⁸ Medical personnel should also be watchful for the appearance of a “dimple sign” over the medial femoral condyle, which is a likely predictor of an externally irreducible dislocation attributable to buttonholing of the medial femoral condyle through the anteromedial joint capsule.^4,7,16 Anteroposterior and lateral radiographs should be obtained in all cases of suspected multiligament injury on account of the high incidence of fractures and avulsions related to knee dislocations.⁸

Physical examination of the lower extremity and knee joint may be limited secondary to pain. A complete examination can be performed under sedation at the time of dislocation reduction.^6,26 Positive findings on the Lachman test, anterior drawer test, varus and valgus stress tests, dial test, pivot-shift or reverse pivot-shift test, or noticeable recurvatum with passive elevation of the lower extremity may provide evidence of the specific pattern of ligament injury, although some of these tests may be difficult to perform even under sedation due to muscle spasms and acute knee swelling.⁸

In a patient with blunt trauma to the lower extremity, a timely and thorough neurovascular examination is of the utmost importance. If gross deformity of the knee joint is noted on primary inspection, a neurovascular examination should be performed prior to reduction, and then repeated post-reduction to ensure continued stability of neurovascular status. The current means of evaluating vascular status include physical examination and ankle-brachial index (ABI) testing. In the presence of hard signs of vascular injury (eg, active hemorrhage, expanding hematoma, or distal ischemia), vascular imaging should be compulsory. Soft findings of vascular injury (eg, limb color changes or delayed capillary refill) will likely necessitate further vascular evaluation, although reliability and clinical value of soft findings remain unclear.^7,22 In the past, arteriography was performed routinely in knee dislocations to assess vascular status. More recently, however, physical examination and ABI have been proven to be dependable predictors of vascular integrity, permitting the use of selective angiography in patients with abnormal physical examination or ABI findings.^13,14,24,27 

When evaluating vascular status, palpation of the dorsalis pedis and posterior tibial pulses is crucial in determining the next step in management. Any asymmetry between the pulses in the lower extremities should raise strong suspicion for vascular injury.^7,9,12,20  There is convincing evidence that palpable pulses rule out vascular compromise in the lower extremity with 100% negative predictive value^.7,17,27 However, many continue to encourage obtaining an ABI even in the presence of normal pulses.⁷ An ABI of >0.9 rules out vascular injury with a negative predictive value of 100%, while an ABI of <0.9 indicates vascular compromise with a sensitivity, specificity, and positive predictive value of 100%.^7,24 In the presence of positive physical examination findings or an abnormal ABI, arteriography is indicated to further evaluate for the existence of vascular injury.²⁸ In a study by Miranda et al,²⁷ 18% to 25% of patients with positive physical examination findings were found to have normal results on arteriography studies, and unwarranted surgical exploration was avoided in these cases.

In addition to the prudent evaluation of vascular status, it is also imperative to perform a careful neurologic examination in patients with knee dislocations due to the high incidence of CPN palsies.¹⁸ As previously mentioned, the anatomical positioning of the CPN at the fibular neck leaves it extremely vulnerable to traction and contusion injuries. Based on the type and extent of injury, the athlete may experience significant, long-term paralysis of the lower extremity.^18,19 Nearly 50% of patients with a peroneal nerve injury are left with permanent neurologic deficits.^18,19 Development of a foot drop is the most common deficit associated with peroneal nerve injury, as innervation to ankle dorsiflexors (eg, tibialis anterior and peroneus longus) are disrupted. These neurologic injuries can be classified using a grading systems such as that of the Louisiana State University Health Sciences Center for peroneal nerve palsy or Medical Research Council muscle grade. These grading scales characterize injuries into various categories based on the strength of contractions of muscles, such as the peronei and tibialis anterior muscles, against resistance.¹⁸ In addition to motor dysfunction, many patients also have continued reports of numbness or paresthesia encompassing the anterolateral lower extremity and foot.¹⁸

Standard Treatment

While it is indisputable that the initial management of a multiligamentous knee dislocation must include reduction and appropriate evaluation and treatment of neurovascular injuries, the superior method for multiligamentous repair remains debatable.²⁹ Much of the discrepancy surrounding what constitutes exceptional management of knee dislocations originates from the rarity of this injury and the lack of large studies and reviews on this topic. If surgical intervention is deemed necessary after initial evaluation, management should then be guided toward maximizing knee stability while minimizing knee stiffness. Historically, knee dislocations were managed with prolonged immobilization of the knee joint. This practice, however, leads to significant knee stiffness and decreased range of motion of the knee joint. Surgical repairs began being described in the later 1800s, with more rigorous studies and reports being published in the mid-1900s. Earlier publications, such as that of Kennedy et al¹⁵ in 1963, suggest comparable outcomes of nonoperative and operative treatments. However, modern advancements in operative technique, surgical resources, and postoperative rehabilitation have proven to provide superior results in patients who are good surgical candidates.²⁶ Currently, surgical versus nonsurgical management must be tailored to the individual and the specific injury, as postsurgical outcome relies heavily on the patient’s ability and motivation to complete a demanding course of physical therapy. When evaluating a patient for surgery, account for age, level of fitness, concomitant injuries, patient motivation, and the postoperative resources available to the patient to aid in rehabilitation. 

•Conservative management. An external fixator is applied post-reduction and left in place for 6 weeks prior to beginning therapy with range of motion maneuvers. It is recommended that serial radiographs be obtained over the immobilization period to ensure that the joint remains in proper alignment.²⁰ While this method helps to restore stability to the affected joint, it also leads to knee stiffness and a tremendous loss in range of motion.²⁶

•Surgical management. Surgical reconstruction in appropriate patients has proven to have better functional results than conservative management.³ Present-day surgical techniques implement a complete repair of all injured structures in the setting of 1 surgery or staged repair in a 2-step fashion. In the 2-step approach, the collateral ligaments, posterolateral structures, and posteromedial structures are all repaired during a primary surgery, which occurs within 2 weeks of injury, while the ACL and PCL are reconstructed during a second surgery. The 1-surgery approach involves the simultaneous reconstruction of bicruciate and collateral ligament. 

Posterolateral corner repairs add a great deal of complexity to reconstructions, but they are crucial in regenerating stability to the knee joint when these injuries are present. The posterolateral corner is composed of the LCL, popliteus tendon complex, arcuate ligament, lateral gastrocnemius tendon, popliteofibular ligament, and posterolateral capsule. All of these structures, which collectively form the posterolateral corner of the knee, provide both dynamic and static stability resistant to varus stress. The importance of diagnosis and appropriate management of posterolateral corner injuries should not be underestimated, as failure to reconstruct posterolateral corner structures is noted to be associated with unsuccessful PCL and ACL grafts, as well as a very high incidence of late-onset osteoarthritis^.29 Once the patient has fully recovered from the initial procedure and has regained full range of motion, a second surgery is scheduled to reconstruct the ACL and PCL.^3,29

Although excellent patient outcomes have been reported with the 2-stage surgical repair, studies have been limited in population size. With this being said, simultaneous bicruciate and collateral ligament reconstruction seems to be the preferred surgical method amongst most surgeons at this point in time. Reconstruction conducted in a single procedure typically occurs around 14 days post-injury. The patient is placed in a knee immobilizer preoperatively and is allowed ample time for edema and acute inflammatory processes to subside preceding surgical repair.²⁶

Neurologic Injury

When neurologic injury is suspected, an MRI or visual examination during surgery may be useful to determine the extent of nerve injury, as a completely severed nerve will significantly hinder the rehabilitation process. In the presence of neurologic impairment, it is generally recommended to have close follow-up with a neurosurgeon for continued evaluation. The performance of an electromyography (EMG) is advocated 3 months post-injury in conjunction with continued assessment of neurologic function through serial physical examinations to determine the extent of injury and evaluate functional outcome prior to considering surgical repair.^8,18,19

Patients who have nerve lesions that remain in continuity have been noted to have spontaneous recovery in 20% of cases.³⁰ In those who do not demonstrate functional improvement post-injury, surgical nerve grafting may be considered. The best predictor of patient prognosis for functional recovery has been for those who are demonstrated to have a lesion in continuity less than 6 cm in length as demonstrated by EMG and nerve conduction studies.^18,19 Although there is the possibility of regaining full neurologic function after nerve grafting, complete recovery occurs in only approximately 21% of patients and partial recovery of motor function has been noted in only approximately 29% of patients.²⁰ 

For those patients who show no functional improvement or fail a nerve grafting operation, tendon transfers have shown promising results for managing foot drop. Tendon transfer procedures typically involve connecting the tibialis posterior tendon to the dorsal aspect of the foot to aid in foot dorsiflexion, and may be considered in patients who do not wish to wear a foot or ankle orthosis. Although it has been documented that tendon transfer procedures provide only 30% of the dorsiflexion strength of the normal contralateral extremity, these procedures do have a patient satisfaction rate as high as 83%.¹⁸

Rehabilitation

As previously mentioned, the rehabilitation process is crucial in the overall outcome of the patient, and therefore each individual patient and case should be carefully considered when contemplating surgical treatment. Younger patients and those with sports-related injuries typically have overall better outcomes than older patients or those who have been involved in high-velocity traumas.^5,6 An optimal outcome requires a multidisciplinary approach with clear and effective communication between physicians, home care nurses, physical therapists, coaches, and the patient.⁷

During the first 6 weeks after surgery, special attention should be given to protecting the knee joint and repaired structures; in fact, the leg should be braced in full extension during the first postoperative week. A knee joint that is left immobilized for an extended period of time will undoubtedly develop adhesions and arthrofibrosis that will greatly restrict the patient’s ability to regain normal range of motion.^2,26,31 Therefore, non–weight-bearing exercises can typically commence 1 week after surgery, but these maneuvers must be well-controlled to avoid undue stress on the newly repaired knee. During the first 6 weeks of recovery, the patient should avoid bearing any weight on the affected extremity and knee flexion beyond 90° should be strictly prohibited. The goal of this initial phase is to gain range of motion by applying appropriate stresses to the knee joint, which help to facilitate physiologic healing responses and proper structure alignment within the reconstructed joint.

Full weight-bearing privileges are generally granted at the beginning of the sixth week of rehabilitation, with the knee maintained in a long postoperative leg brace. Once the patient is able to ambulate without crutches, the long brace can be exchanged for a functional brace that is to be worn during all activities until 12 weeks after surgery. Goals of rehabilitation during weeks 6 to 12 after surgery emphasize regaining maximum physiologic range of motion while also strengthening the surrounding muscles to aid in knee joint stability.²⁶

More aggressive exercises are instituted between weeks 12 and 24 after surgery. During this time period, the objective is to progress the patient through a range of maneuvers and movements guided toward improving muscle power and proprioception. Acceleration, deceleration, and slideboard drills aid in retraining primary motor responses to assist in compensatory reflex patterns. By improving neuromuscular reactive stability, patients are more likely to be able to return to their pre-injury performance level with less chance of reinjury.²⁶

After 24 weeks, low-intensity agility drills can be incorporated into the rehabilitation program. Throughout this final stage of rehabilitation, the target is to promote sport-specific or work-specific maneuvers to test the patient’s abilities to perform functionally specific actions. A functional test algorithm is generally used to gauge the patient’s progress. The patient must advance through a series of progressively difficult challenges. If the patient fails a certain aspect of the functional test algorithm, then the rehabilitation program becomes concentrated on improving the functional insufficiency until he or she is able to perform at an adequate level.²⁶ Many experts agree that activity restrictions should remain in place and that an athlete should not return to full, unrestricted sporting activities until 9 to 12 months after surgery.^2,7 It is also widely recommended that patients continue to wear a functional brace during athletics or physically demanding occupational activity for at least 18 months postoperatively.^2,26

Although tremendous strides have been made in minimizing devastating complications and improving the surgical outcome and rehabilitation of multiligamentous knee injuries, a full return to pre-injury performance level remains rare. When the functional status of a group of patients was assessed using an International Knee Documentation score, 39% of postsurgical patients were rated as nearly normal, 40% as abnormal, and 21% as severely abnormal.^4,21,32,33 On a similar note, a case series of elite athletes demonstrated that 79% were able to return to their sport after injury and rehabilitation, with only 33% of those athletes performing at the same level that they had been competing at prior to their injury.^19,34 

Prevention

In hopes of preventing severe and likely career-ending injuries in athletes, a great deal of focus has been placed on determining ways to elude multiligamentous knee injuries. In regard to ACL injuries, women have been demonstrated to have a 2- to 10-fold increase in injury incidence when compared with males. This has been speculated to be attributable either to small anatomical variances in the female body or hormonal differences that tend to leave female athletes more vulnerable to knee injuries over male athletes.³³

A multitude of environmental factors may also expose athletes to greater risk of knee injury. While athletic footwear (eg, cleats) can improve performance by providing the participant with better control during acceleration and cutting movements, certain footwear also puts the athlete at risk by restricting rotational movement and prohibiting the foot from releasing from the ground during collisions. In addition to footwear, certain playing surfaces have also been implicated in injury. Injuries have been noted to occur less frequently on surfaces that offer a lower friction coefficient and in weather that decreases the friction coefficient, such as cold or wet conditions. 

Although taking footwear and specific playing surfaces into consideration may help to reduce the risk of knee injuries, more convincing evidence for the prevention of knee injuries has surfaced from studies examining injury prevention programs.³³ There are not many publications on the prevention of multiligamentous knee injuries, but numerous studies are available regarding ACL injury prevention, as ACL injuries have become commonplace in athletes of all ages and skill levels. One ACL injury prevention program with remarkable results involves the employment of a 20-minute warm-up to include agility, flexibility, biomechanics, and muscle strengthening. The results of this study demonstrated an 88% decreased in noncontact ACL injuries in the first year of implementation and a 74% decrease in noncontact ACL injuries in the second year.^21,35 Although more research is needed to demonstrate the efficacy of training programs in preventing multiligamentous injuries, this study has laid the groundwork to suggest that a large number of knee injuries can be avoided through proper training.

Multiligamentous knee injuries are exceptionally rare, yet have the potential for overwhelming complications. Thorough and repeated neurovascular examinations are essential in diagnosing vascular and neurologic compromise in knee dislocations, and swift action in the face of neurovascular injury can drastically reduce morbidity. Palpation of lower-extremity pulses and an ABI have proven to be accurate methods for ruling out vascular injury. Although routine angiography is no longer advised, it should be performed for any patient demonstrating abnormal lower-extremity pulses or an ABI of <0.9, as unwarranted vascular surgery can be avoided in a large percentage of patients. By reducing the incidence of delayed identification or the misdiagnosis of knee dislocations, determining appropriate surgical candidates, addressing any neurologic impairments, and providing appropriate rehabilitation in the postoperative period, patients are afforded better overall outcomes in the face of truly devastating knee injuries.

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