Practical management of knee dislocations: a selective angiography protocol to detect limb-threatening vascular injuries

Tibiofemoral Dislocation Management in a Rural High School Football Scenario: Development of a Popliteal Artery Injury Suspicion Index

OBJECTIVE

This study evaluated the knowledge and preparedness of athletic trainers (ATs) for diagnosing and managing an anterior tibiofemoral knee dislocation in a rural or limited-resource high school football setting scenario. The study hypothesis was that more experienced ATs would display greater preparedness than less experienced ATs. A secondary objective was to develop evidence-based guidelines to help the AT provide better emergency triage care.

METHODS

This prospective cross-sectional study distributed a rural high school football game scenario survey electronically to a random sample of 2000 certified ATs to determine their perceptions of readiness to diagnose and manage an anterior tibiofemoral knee dislocation with signs or symptoms of possible popliteal artery injury.

RESULTS

A total of 249 surveys (12.5%) were completed. Years of athletic training experience were ≤5 years (n = 82, group 1) and ≥6 years (n = 167, group 2). Both groups perceived that they could not "rule out" an arterial injury and had similar "red flag" sign and symptom rankings. Group 2 perceived a more serious situation than group 1 (77.5 ± 15 vs 70.8 ± 14, P < 0.0001) and were more likely to activate the emergency action plan (74.5 ± 25 vs 64.4 ± 26, P = 0.005). Both groups were "neutral" about their ability to diagnose the condition or manage the case, had poor ankle-brachial index test familiarity, and agreed that evidence-based guidance was needed.

CONCLUSIONS

More experienced ATs perceived a more serious situation than less experienced ATs and were more likely to activate the emergency action plan. Both groups were neutral about their ability to diagnose the condition or manage the case, had poor ankle-brachial index test familiarity, and agreed that they would benefit from evidence-based guidance. Proposed guidelines provide the AT with a more measured, evidence-based index of suspicion for potential popliteal artery injury in anterior tibiofemoral dislocation cases. This will complement existing hospital emergency department-based management algorithms, decreasing the likelihood of this condition progressing to limb loss or death.

Increased Neurovascular Morbidity Is Seen in Documented Knee Dislocation Versus Multiligamentous Knee Injury

This article was updated on May 19, 2021 because of previous errors, which were discovered after the preliminary version of the article was posted online. In the legend for Figure 3-A, the phrase that had read "T1-weighted coronal MRI showing a right knee" now reads "T1-weighted coronal MRI showing a left knee." On page 924, in the section entitled "Materials and Methods," the sentence that had read "If there was no radiographic evidence or if there was a clinical note that documented visible deformity around the knee with no reduction maneuver being performed, then the patient was classified into the non-dislocated MLKI group." now reads "If there was no radiographic evidence or if there was no clinical note that documented visible deformity around the knee with no reduction maneuver being performed, then the patient was classified into the non-dislocated MLKI group." On page 925, in the section entitled "Analysis," the sentence that had read "Our study included 78 dislocated MLKIs and non-dislocated MLKIs, so both cohorts were adequately powered for the overall analysis." now reads "Our study included 45 dislocated MLKIs and 78 non-dislocated MLKIs, so both cohorts were adequately powered for the overall analysis." Finally, on page 927, in the section entitled "Discussion," the sentence that had read "Interestingly, we found that MLKIs with a documented knee dislocation had a substantially higher rate of vascular injury (23%) compared with those without (3%)." now reads "Interestingly, we found that MLKIs with a documented knee dislocation had a substantially higher rate of vascular injury (18%) compared with those without (4%)."

[Emergency treatment of dislocation of large joints]

Joint dislocations are always accompanied by rupture of the joint capsule. Depending on the forces exerted on the joint as well as individual bone quality, fractures (dislocation fractures) and injuries to ligaments occur. As blood vessels and nerves can also be damaged, reduction is an urgent measure. Only impaired peripheral perfusion, loss of motor function or sensation justify reduction without radiological documentation. As reduction can be a painful procedure, analgosedation is nearly always necessary. Evidence for superiority of individual maneuvers is weak. Reduction is followed by immobilization and documented by another control X‑ray. Follow-up treatment depends on concomitant injuries, age and individual demands on joint function. Even with correct follow-up treatment, deficits often persist. This article deals with the diagnostics and treatment of dislocations of the shoulder, elbow, hip, patella and knee.

The Pathoanatomy of Posterolateral Corner Ligamentous Disruption in Multiligament Knee Injuries Is Predictive of Peroneal Nerve Injury

BACKGROUND

A description of the precise locations of ligamentous and myotendinous injury patterns of acute posterolateral corner (PLC) injuries and their associated osseous and neurovascular injuries is lacking in the literature.

PURPOSE

To characterize the ligamentous and myotendinous injury patterns and zones of injury that occur in acute PLC injuries and determine associated rates of peroneal nerve palsies and vascular injuries, as well as fracture and dislocation.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We retrospectively identified all patients treated for an acute multiligament knee injury (MLKI) at our level 1 trauma center from 2001 to 2018. From this cohort, all patients with PLC injuries were identified. Demographics, involved ligaments and tendons, neurovascular injury, and presence of fracture and dislocation were compared with the larger multiligament knee cohort. Incidence and location of injury of PLC structures-from proximal to midsubstance and distal injury-were recorded.

RESULTS

A total of 100 knees in 100 patients were identified as having MLKIs. A total of 74 patients (74%) had lateral-sided ligament injuries. Of these, 23 (31%) had a peroneal nerve palsy associated with their injury; 10 (14%), a vascular injury; and 23 (31%), a fracture. Patients with PLC injuries had higher rates of peroneal nerve injury as compared with those having acute MLKIs without a PLC injury (31% vs 4%; P = .005). Patients with a complete peroneal nerve palsy (n = 17) were less likely to regain function than those with a partial peroneal nerve palsy (n = 6; 12% vs 100%; P < .0001). Complete injury to the lateral collateral ligament (LCL) occurred in 71 of 74 (96%) PLC injuries, with 3 distinct patterns of injury demonstrated. Fibular avulsion of the LCL was the most common zone of injury (65%), followed by femoral avulsion (20%) and midsubstance tear (15%). Location of injury to the LCL was associated with the rate of peroneal nerve injury, with midsubstance tears and fibular avulsions associated with higher rates of peroneal nerve injury.

CONCLUSION

MLKIs with involvement of the PLC are more likely to suffer peroneal nerve injury. The LCL is nearly always involved, and its location of injury is predictive of peroneal nerve injury. Patients with a complete peroneal nerve palsy at presentation are much less likely to regain function.

Multi-link endoscopic manipulator robot actuated by shape memory alloys spring actuators controlled by a sliding mode

The aim of this study was to design and evaluate a prototype of a snake-like endoscopic manipulator robot (SLEMR) and its corresponding automatic controller based on the first order sliding mode theory. The SLEMR was controlled with a set of actuators made of shape memory alloys (SMA). The SLEMR device was constructed with a sequential arrangement of links interconnected by a two degree-of-freedom joint. A parallel agonist-antagonist configuration of actuators was implemented to move each joint. The physical relation between temperature and elongation in SMA forced the execution of the movement in the joint. Elongation-temperature model of the SMA actuator served to get a feasible bound of velocity for each joint. Each pair of SMA actuators was controlled by a first order sliding mode controller. This control design solved the tracking trajectory problem for each joint in the SLEMR because of its robustness against uncertainties and external perturbations. The control action was projected into a feasible implementable set of pulse-width modulated signals which was used to regulate the temperature of the corresponding SMA actuator. The controller designed in this study was experimentally validated in a SLEMR made up by a tridimensional printing technique. The control strategy induced the successful trajectory tracking for all the joints in the SLEMR simultaneously. This characteristic of the control design also enforces the tracking of a reference position by the tip of the final link of the SLEMR. An image acquisition system was used to determine the position of the final actuator in the SLEMR. The effectiveness of the controller proposed in this study was confirmed by the evaluation of the tracking error of the final actuator which approached to a bounded region (less than 1.0 mm) near the origin in a finite-time (0.5 s).

Varus mechanism is associated with high incidence of popliteal artery lesions in multiligament knee injuries

PURPOSE

This study aims to identify multiple ligament knee injury patterns that possess a high-risk of vascular lesion.

METHODS

We retrospectively compared torn ligament patterns and the presence of vascular lesions confirmed by magnetic resonance imaging and computed tomography angiography from 122 consecutive patients with diagnoses of multiple ligament knee injury made at the emergency department between January 2012 and December 2017. Patients were not eligible if they had an ipsilateral lower extremity lesion (dislocations or fractures at another level), initial evaluation at another hospital, or follow-up for less than 12 months. The primary outcomes were the comparison between the imaging findings of torn structures patterns and the presence of a vascular lesion.

RESULTS

We identified 48 eligible patients (50 knees) with multiligamentary knee lesions, of whom eight had popliteal artery damage, yielding an incidence of 16%. Our clinical examination detected six of these patients that were classified, according to the Schenck system, as KD-IIIL (6 knees) and KD-IIIM (2 knees). The odds of having a popliteal artery injury is 4.69 to 1 with a KD-IIIL injury that with any other type of injury on that classification (95% CI 0.960-22.98).

CONCLUSIONS

This data suggests that varus forces causing enough energy to produce a KD-IIIL lesion possess a higher popliteal artery injury risk, making recommendable a thorough examination of the vascular integrity when diagnosing a KD-IIIL lesion.

Evaluation and Management of Knee Dislocation in the Emergency Department

BACKGROUND

Knee dislocations are a potentially limb-threatening injury, and it is essential that emergency medicine clinicians are aware of them.

OBJECTIVE

This article provides a review of the diagnosis and management of knee dislocation for the emergency provider.

DISCUSSION

Knee dislocations are uncommon injuries with the potential for significant morbidity. A thorough history and examination are important, because 50% of dislocations may have reduced before arrival to the emergency department. Knee dislocations should be quickly reduced in the emergency department setting. The presence of equal pulses does not exclude vascular injury, and all patients should undergo serial vascular examinations and evaluation with ankle-brachial indices. Those with abnormal ankle-brachial indices should receive computed tomographic angiography. Radiographs are important to identify any fractures, while magnetic resonance imaging may be deferred until after admission.

CONCLUSION

Knee dislocation is a potentially dangerous medical condition requiring rapid diagnosis and management. It is essential for emergency clinicians to know how to diagnose and treat this disorder.

From the central pivot to the peripheal knee injuries in the skier: a narrative review

The improvement in the technology in the last 20 years has showed its main effect on the increase of the speed in the curves, thus leading to a rise of knee injuries. In fact, the most injured zone of the body was the knee (35,6 %) and the distal part of the lower body (11,5%), with ACL lesion as the most frequent diagnosis (49% of all the injuries to the knee) due to a trauma in valgus and external rotation in most of cases. The MCL is involved in the 15-20% of the cases while the LCL in only the 4,2% of the patients. Unique epidemiology and distinct mechanisms of injuries are peculiar for skier’s knee while evaluation and treatment is similar to evaluation and treatment of knee injuries in other athletes. In this narrative review we aimed to highlight the current evidences in skiers’ traumatology with special focus on the treatment nowadays proposed in the international literature and to the return to sport. (www.actabiomedica.it)

Knee and Leg Injuries

Knee and leg injuries are extremely common presentations to the emergency department. Understanding the anatomy of the knee, particularly the vasculature and ligamentous structures, can help emergency physicians (EPs) diagnose and manage these injuries. Use of musculoskeletal ultrasonography can further aid EPs through the diagnostic process. Proper use of knee immobilizers can also improve long-term patient outcomes.

Knee dislocation with popliteal artery disruption: A nationwide analysis from 2005 to 2013

Objective

Few have compared short-term outcomes following knee dislocations with or without concomitant popliteal artery disruption (PAD).

Methods

The Nationwide Inpatient Sample was used to identify 2175 patients admitted for knee dislocation from 2005 to 2013 (concomitant PAD: n = 210/9.7%; without: n = 1965/90.3%).

Results

Patients with PAD were younger, more often male, Black and Hispanic, and with Medicaid (all p ≤ 0.013). PADs were associated with 11.0-times higher odds of increased LOS (95%CI, 6.6-18.4) and 2.8-times higher odds of experiencing any complication (95%CI, 2.03-3.92). Female sex was a protective factor against increased LOS, (OR = 0.65; 95%CI, 0.48-0.88).

Conclusion

High suspicion index should be maintained for concomitant vascular injuries following knee dislocations.

Management of knee dislocation prior to ligament reconstruction: What is the current evidence? Update of a universal treatment algorithm

Traumatic knee dislocation is a rare but potentially limb-threatening injury. Thus proper initial diagnosis and treatment up to final ligament reconstruction are extremely important and a precondition to successful outcomes. Reports suggest that evidence-based systematic approaches lead to better results. Because of the complexity of this injury and the inhomogeneity of related literature, there are still various controversies and knowledge gaps regarding decision-making and step-sequencing in the treatment of acute multi-ligament knee injuries and knee dislocations. The use of ankle-brachial index, routine or selective angiography, braces, joint-spanning or dynamic external fixation, and the necessity of initial ligament re-fixation during acute surgery constitutes current topics of a scholarly debate. The aim of this article was to provide a comprehensive literature review bringing light into some important aspects about the initial treatment of knee dislocation (vascular injury, neural injury, immobilization techniques) and finally develop an accurate data-based universal algorithm, enabling attending physicians to become more acquainted with the management of acute knee dislocation.

Increased Incidence of Vascular Injury in Obese Patients With Knee Dislocations

OBJECTIVES

With rising rates of obesity in the United States, the burden of knee dislocations in this population remains unknown. This national epidemiologic study was designed to analyze the association of obesity with closed knee dislocation and vascular complications.

DESIGN

Retrospective cohort study.

SETTING

The deidentified Nationwide Inpatient Sample database was used to access the US inpatient data from 2000 to 2012.

PATIENTS/PARTICIPANTS

Patients with noncongenital closed knee dislocations were included. Examined variables included patient age, sex, vascular injury, and obesity status.

MAIN OUTCOME MEASURES

Outcome measures included hospital length of stay, amputation, and inpatient hospitalization charge.

RESULTS

From 2000 to 2012, a total of 19,087 knee dislocations were identified, including 2265 in overweight/obese patients (11.9%). The annual incidence of knee dislocations reported in patients diagnosed as either obese or morbidly obese increased over the 13-year period (P < 0.0001). The overall average rate of vascular injury requiring intervention was 5.63%, whereas 7.2% of obese patients and 11.3% of morbidly obese patients with knee dislocations (P < 0.0001) sustained a vascular injury requiring intervention. The average length of stay and amputation rate for obese and morbidly obese patients who sustained a knee dislocation was not statistically different from nonobese patients when vascular injury was controlled. When patients with a vascular injury were excluded, obese and morbidly obese patients who sustained a knee dislocation had higher average cost of hospital stay than nonobese patients (P = 0.0262).

CONCLUSIONS

This study demonstrates significant increases in costs of stay with obese patients sustaining knee dislocations when compared with normal weight knee dislocation patients. Vascular injuries were found to be far more common in obese and morbidly obese patient groups than nonobese patients. Providers should be on high alert when managing knee dislocations in obese patients because a significant number require prompt vascular intervention.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Knee Dislocation: A Case Report, Diagnostic Vascular Work-Up, and Literature Review

Knee dislocation is an uncommon, potentially limb-threatening, knee injury. Most often caused by high-velocity trauma, it can also result from low- or even ultra-low-velocity trauma. Rapid identification of the injury, reduction, and definitive management are necessary to minimize neurovascular damage. We present a case of rotatory anterolateral knee dislocation sustained during a twisting sports-related event. Special emphasis is placed on diagnosing vascular injuries associated with knee dislocations.

Knee Dislocations in Sports Injuries

Knee dislocations are devastating when they occur on the athletic field or secondary to motor sports. The complexity of presentation and spectrum of treatment options makes these injuries unique and extremely challenging to even the most experienced knee surgeons. An astute appreciation of the treatment algorithm is essential to plan individualized management since no two complex knee dislocations are ever the same. Moreover, attention to detail and finesse of surgical technique are required to obtain a good functional result and ensure return to play. Over the past 10 years, our service has treated 43 competitive sportsmen with knee dislocations, and this experience forms the basis for this narrative review.

Can Vascular Injury be Appropriately Assessed With Physical Examination After Knee Dislocation?

BACKGROUND

Knee dislocations are rare injuries with potentially devastating vascular complications. An expeditious and accurate diagnosis is necessary, as failing to diagnose vascular injury can result in amputation; however, the best diagnostic approach remains controversial.

QUESTIONS/PURPOSES

We asked: (1) What patient factors are predictors of vascular injury after knee dislocation? (2) What are the diagnostic utilities of palpable dorsalis pedis or posterior tibial pulses, and the presence of an ankle-brachial index (ABI) of 0.9 or greater?

METHODS

A database at a Level I trauma center was queried for patients with evidence of knee dislocation, demographic information (age at the time of injury, sex, Injury Severity Score, BMI, mechanism of injury), and the presence of open injury were recorded. One-hundred forty-one patients underwent screening at initial presentation, of whom 26 (24%) underwent early vascular exploration based on an abnormal physical examination. One-hundred five (91%) of the remaining 115 patients were available at a minimum followup of 6 months (mean, 19 ± 10 months). In total, 31 unique patients were excluded, including 10 patients (7%) who were lost to followup before 6 months. Among the 110 patients who met inclusion criteria, the mean age and SD was 37 ± 13 years, and the Injury Severity Score was 15 ± 9. There were 71 males (65%). Logistic regression was used to determine independent correlates of vascular injury. The vascular examination was reviewed for the presence of a palpable pulse in the dorsalis pedis artery, the presence of a palpable pulse in the posterior tibial artery, and whether the ABI in the dorsalis pedis was 0.9 or greater. Contingency tables were generated to assess the sensitivity, specificity, and accuracy of physical examination maneuvers. The physical examination was collectively regarded as "normal" when both pulses were palpable and the ABI was 0.9 or greater. The initial physical examination as just described was considered the diagnostic test being evaluated in this study; "positive" tests were evaluated by and confirmed at vascular surgery, and 6 months clinical followup without symptoms or progressive signs of vascular injury confirmed the absence of injury in the remainder of the patients. Contingency tables were generated again to assess the sensitivity, specificity, and accuracy of the combined physical examination.

RESULTS

Increased BMI (odds ratio [OR], 1.077; 95% CI, 1.008-1.155; p = 0.033) and open injuries (OR, 3.366; 95% CI, 1.008-11.420; p = 0.048) were associated with vascular injury. No single physical examination maneuver had a 100% sensitivity for ruling out vascular injury. A normal physical examination (palpable pulses and ABI ≥ 0.9) had 100% sensitivity for ruling out vascular injury.

CONCLUSIONS

Increased BMI and the presence of open dislocation are associated with a greater risk for vascular injury after knee dislocation. The combination of a palpable dorsalis pedis and posterior tibial pulse combined with an ABI of 0.9 or greater was 100% sensitive for the detection of vascular injury based on clinical followup at 6 months.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Knee dislocation and vascular injury: 4 year experience at a UK Major Trauma Centre and vascular hub

INTRODUCTION

Knee dislocation is a rare but potentially devastating injury. Quoted rates of associated vascular compromise vary dramatically between 3.3% and 64%, and the best approach to investigate and diagnose such an injury remains controversial. We aim to evaluate our own 4-year experience of knee dislocation and vascular injury as a UK Major Trauma Centre and vascular hub.

METHODS

Knee dislocation was defined as disruption of at least two major stabilising ligaments of the knee and gross instability requiring an operation. Patients were identified from the Department of Trauma and Orthopaedics patient database across a 4 year period from 2010 to 2014. Electronic patient records, imaging and hard notes were retrieved and reviewed retrospectively and relevant information recorded.

RESULTS

Twenty-five cases of knee dislocation were identified. Male to female ratio was 11.5:1 with a mean age of 33 years (range 17-71). One patient had a vascular injury which ultimately required a femoro-popliteal bypass graft. Twenty-four patients had documented examination findings pertaining to the vascular status of the limb. Seventeen patients had specific reference to the presence or absence of pedal pulses. The remaining seven cases were documented as either "warm well perfused" or "neurovascularly in-tact". Nine patients were discharged directly from the emergency department with outpatient follow up. All admitted cases had documented vascular examination findings the following day. Two patients had additional adjunctive non-invasive investigations. No patients were examined with duplex ultrasound, although two patients had pulses confirmed with hand-held doppler ultrasound. Three patients had an angiogram. Four cases have a documented discussion with or review from a vascular surgeon.

DISCUSSION AND CONCLUSIONS

Our rates of vascular injury are in line with the most recent and largest study to date. Non-invasive investigation and selective angiography has been safe in identifying significant vascular compromise, however, there is inconsistency in management pathways, and too much reassurance attributed to the presence of pedal pulses on initial examination. Safety and consistency could be improved with the introduction of a formalised evidence-based protocol for the initial evaluation of knee dislocation and vascular injury.

Acute Management of Traumatic Knee Dislocations for the Generalist

Acute knee dislocations are an uncommon injury that can result in profound consequences if not recognized and managed appropriately on presentation. Patients presenting with knee pain in the setting of high- or low-energy trauma may have sustained a knee dislocation that spontaneously reduced. Prompt reduction of the dislocated knee and serial neurovascular examinations are paramount. Damage to the popliteal artery is a common associated injury that can be diagnosed on physical examination using ankle brachial indices (ABIs), CT angiography, or standard angiography. After reduction, patients with a normal pulse examination and an ABI ≥0.9 may be observed, with serial examination performed to document vascular status and monitor for compartment syndrome. Patients with asymmetric pulses or an ABI <0.9 in the presence of pulses may be treated urgently depending on the results of additional vascular imaging, and patients with absent pulses and clear signs of vascular compromise should be treated emergently. Some knee dislocations are not reducible and should be taken emergently to the operating room for an open reduction. Persistent joint subluxation or severe soft-tissue injuries after reduction require temporary external fixation before definitive repair or reconstruction of ligaments is performed.

Popliteal artery injury associated with blunt trauma to the knee without fracture or dislocation

Popliteal artery injuries are frequently seen with fractures, dislocations, or penetrating injuries. Concern about arterial injury and early recognition of the possibility of arterial injury is crucial for the salvage of the extremity. This article provides an outline of the diagnostic challenges related to these rare vascular injuries and emphasizes the necessity for a high level of suspicion, even in the absence of a significant penetrating injury, knee dislocation, fracture, or high-velocity trauma mechanism. The importance of a detailed vascular examination of a blunt trauma patient is emphasized.

What is the frequency of vascular injury after knee dislocation?

BACKGROUND

Vascular injury secondary to an acute knee dislocation is a known complication. However, there exist wide discrepancies in the reported rate of vascular injury in this setting.

QUESTIONS/PURPOSES

Using a large private insurance database, we determined the frequency of vascular injury in knee dislocations across year of diagnosis, age, sex, and US geographic region and the proportion of these injuries requiring surgical repair.

METHODS

The PearlDiver database, which contains records from 11 million orthopaedic patients, was searched using ICD-9 diagnostic codes for all knee dislocation events from 2004 to 2009. Within this subset, we identified which knee dislocations had an associated vascular injury ICD-9 code. Patients were stratified by year of diagnosis, age, sex, and US geographic region, and Current Procedural Terminology codes were used to identify the subset of patients with vascular injury requiring surgical repair. Differences in frequency across demographic groups and over time were analyzed with Poisson regression analysis.

RESULTS

Among the 8050 limbs with knee dislocation identified over the study period, 267 had a concomitant vascular injury for an overall frequency of 3.3%. Males were found to have an increased risk of vascular injury compared to females (odds ratio = 2.59, p < 0.001). Additionally, patients aged 20 to 39 years had a higher risk of vascular injury when compared to those aged 0 to 19 years (odds ratio = 1.93, p = 0.001), 40 to 59 years (odds ratio = 1.57, p = 0.014), and 60 years or older (odds ratio = 2.81, p = 0.036). There were no differences in vascular injury frequency across US geographic regions or diagnosis year. Thirty-four of the 267 cases of vascular injury (13%) underwent surgical treatment.

CONCLUSIONS

This is the largest study, to our knowledge, that analyzes the proportion of knee dislocations that result in vascular injury. Our data suggest that there is a lower frequency of vascular injury associated with knee dislocation and a lower proportion of vascular injuries undergoing surgical treatment than previously reported. These findings may support a more selective angiography protocol to screen for vascular injury, rather than performing this invasive diagnostic test on all knee dislocations, as has been done historically. Future large-scale and prospective studies should analyze factors that may predispose to vascular injuries after knee dislocation and determine which patients should be screened for vascular injury after knee dislocation.

LEVEL OF EVIDENCE

Level IV, prognostic study. See Instructions for Authors for a complete description of levels of evidence.

Vascular and nerve injury after knee dislocation: a systematic review

BACKGROUND

Vascular injury is a devastating complication of acute knee dislocation. However, there are wide discrepancies in the reported frequency of vascular injury after knee dislocations, as well as important differences among approaches for diagnosis of this potentially limb-threatening problem.

QUESTIONS/PURPOSES

We determined (1) the frequency of vascular and neurologic injury after knee dislocation and whether it varied by the type of knee dislocation, (2) the frequency with which surgical intervention was performed for vascular injury in this setting, and (3) the frequency with which each imaging modality was used to detect vascular injury.

METHODS

We searched the MEDLINE(®) literature database for studies in English that examined the clinical sequelae and diagnostic evaluation after knee dislocation. Vascular and nerve injury incidence after knee dislocation, surgical repair rate within vascular injury, and amputation rate after vascular injury were used to perform a meta-analysis. Other measures such as diagnostic modality used and the vessel injured after knee dislocation were also evaluated.

RESULTS

We identified 862 patients with knee dislocations, of whom 171 sustained vascular injury, yielding a weighted frequency of 18%. The frequency of nerve injuries after knee dislocation was 25% (75 of 272). We found that 80% (134 of 160) of vascular injuries underwent repair, and 12% (22 of 134) of vascular injuries resulted in amputation. The Schenck and Kennedy knee dislocation classifications with the highest vascular injury prevalence were observed in knees that involved the ACL, PCL, and medial collateral liagment (KDIIIL) (32%) and posterior dislocation (25%), respectively. Selective angiography was the most frequently used diagnostic modality (61%, 14 of 23), followed by nonselective angiography and duplex ultrasonography (22%, five of 23), ankle-brachial index (17%, four of 23), and MR angiography (9%, two of 23).

CONCLUSIONS

This review enhances our understanding of the frequency of vascular injury and repair, amputation, and nerve injuries after knee dislocation. It also illustrates the lack of consensus among practitioners regarding the diagnostic and treatment algorithm for vascular injury. After pooling existing data on this topic, no outcomes-driven conclusions could be drawn regarding the ideal diagnostic modality or indications for surgical repair. In light of these findings and the morbidity associated with a missed diagnosis, clinicians should err on the side of caution in ruling out arterial injury.

Current concepts in acute knee dislocation: the missed diagnosis?

Traumatic knee dislocation is a serious and potentially limb threatening injury that can be easily missed if meticulous history and examination have not been employed. Neurovascular injuries are common in this condition, and due diligence should be given to their thorough evaluation at time of secondary survey so as to avoid complications such as ischaemia, compartment syndrome and eventual amputation. There is growing evidence in the literature that morbid obesity is associated with low energy knee dislocation, therefore this should be considered when assessing this cohort of patients presenting with an acute knee injury. Early operative intervention especially with multi ligaments involvement is the preferable strategy in the management of this acute injury. Controversy exists whether to reconstruct or repair damaged structures, and whether to adopt a one stage or two stage reconstruction of the cruciate ligaments. Early rehabilitation is important and essential to achieve satisfactory outcomes. This article is an evidence-based overview of this rare but devastating injury.

Acute knee dislocation

Traumatic knee dislocations are relatively rare yet serious injuries. They remain under diagnosed injuries in view of the frequency with which they can present having spontaneously reduced. Diagnosis requires a high index of clinical suspicion on presentation of all knee injuries. Careful, repeated and vigilant monitoring for neurovascular compromise following diagnosis, appropriate investigations and early involvement of surgeons with a specialist interest in knee ligament injury are important factors in managing these injuries. The prognosis has improved in recent years following establishment of some consensus on the evaluation, investigation, management and rehabilitation of these injuries and this article presents an evidence based review of these principles.

Radiologic review of knee dislocation: from diagnosis to repair

OBJECTIVE

This imaging-based article systematically reviews traumatic knee dislocations. After completion, the reader should be familiar with the definition, epidemiology, cause, and classification schemes associated with these injuries, as well as the importance of timely diagnostic imaging and an accurate, detailed description of findings, particularly as it relates to MRI interpretation. Finally, information our orthopedic surgical colleagues consider critical for the preoperative planning and reconstruction of the multiple ligament knee injury will be discussed.

CONCLUSION

Although uncommon, traumatic knee dislocations are an important potentially limb-threatening injury, which if not emergently recognized and appropriately managed, can result in significant patient morbidity, joint dysfunction, chronic pain, and long-term disability. A radiologist familiar with the imaging appearance and potential neurovascular complications associated with these injuries can play an integral role in the multidisciplinary team that manages this increasingly recognized clinical entity.

[Vascular injuries associated with dislocation of the knee: diagnosis protocol]

INTRODUCTION

Knee dislocation is an unusual condition, and can have catastrophic consequences, such as vascular and neurological complications, in addition to the ligament injuries.

OBJECTIVE

The aim of this study is to analyse the effectiveness of a protocol of early diagnosis of vascular injuries associated with knee dislocations.

MATERIALS AND METHODS

A retrospective study was conducted which included acute knee dislocations treated in our institution, with a minimum of 12 months follow-up, between 1999-2010. A diagnostic protocol based on physical examination and ankle-brachial index was used in order to detect vascular injuries.

RESULTS

Ten dislocations, 30% with popliteal artery injury, were diagnosed early and received emergency treatment within 8 hours. There were associated neurological injuries in two patients. There were no amputations.

CONCLUSIONS

The systematic use of this protocol has avoided consequences of late diagnosis and has drastically reduced the abusive use of invasive tests, such as arteriography.

Acute knee dislocation: an evidence based approach to the management of the multiligament injured knee

Traumatic knee dislocations are uncommon yet serious injuries that historically have had variable prognosis. The evaluation and management of traumatic knee dislocations remains controversial. Appropriate early management has been shown to have a significant impact on long term functional outcome. A comprehensive review of the recent literature is presented alongside our current approach to management. The dislocated knee is an under diagnosed injury which relies on a high index of clinical suspicion on presentation of any knee injury. There is now a degree of consensus regarding need for surgery, timing of surgery, vascular investigations, surgical techniques and rehabilitation protocols. Vigilant monitoring for neurovascular complications, appropriate investigations and early involvement of surgeons with a specialist interest in knee ligament surgeries is the key to successful management of these difficult injuries.

Diagnosis and management of knee dislocations

An acute knee dislocation is an uncommon injury, with a high rate of associated vascular and neurologic injuries as well as potentially limb-threatening complications. High-energy trauma is the most common cause of an acute knee dislocation, although lower-energy injuries, such as those sustained during athletic competition, are increasing in incidence. Injuries to the popliteal artery and common peroneal nerve are relatively common, requiring a high index of suspicion and complete neurovascular examination in a timely fashion. All cases of suspected knee dislocation should have an ankle-brachial index performed, reserving arteriography for those with an abnormal finding. Initial management consists of closed reduction, if possible, and application of a hinged brace or external fixator. Definitive management remains an area of controversy, although anatomic surgical repair or reconstruction is favored by most surgeons to help optimize knee function. Most patients treated for a knee dislocation can expect to return to their daily activities, but with less predictable returns to sporting activities.

Blunt trauma of the anterior tibial artery in professional footballers

Three cases of blunt trauma to the anterior tibial artery in professional footballers are described. Each case was managed conservatively, allowing the players to promptly return to competitive fixtures. We hope the outcomes of the cases described might be helpful for teams facing the challenge of managing similar injuries.

Knee and leg injuries

The knee plays a significant role in ambulation and the activities of daily living. During the course of these activities and its role in weight bearing, the knee is susceptible to a variety of different forces and the emergency physician should be familiar with the diagnosis and treatment of the injuries that result. In addition to following basic trauma protocols, thorough neurovascular and musculoskeletal examinations should be performed and supplemented with appropriate imaging. Emergency physicians should also consider recent developments in knee anatomy and function when evaluating the patient with an acutely injured knee.

Risk management and avoiding legal pitfalls in the emergency treatment of high-risk orthopedic injuries

Avoiding legal pitfalls of orthopedic injuries in the emergency department (ED) requires an understanding of certain high-risk injuries, their presentation, evaluation, and disposition. Various pitfalls pertaining to both upper and lower extremity injuries are discussed in detail, with recommendations regarding the history, physical examination, and radiographic techniques that minimize the risk inherent in these injuries. When approaching these injuries in the ED, a high level of suspicion coupled with appropriate evaluation and management will allow the practitioner to avoid mismanagement of these potential pitfall cases.