Magnetic resonance imaging of the multiple-ligament injured knee

The known and unknown reality of knee dislocations: A systematic review

BACKGROUND

Knee dislocations (KD) are limb threatening injuries known to cause significant dysfunction and disability. This review aims to summarize KD knowledge and uncover areas where more research is needed.

METHODS

The published literature was queried according to PRISMA guidelines. Studies eligible for inclusion were clinical studies of knee dislocations. Studies published before 1990, or that focused on patellofemoral dislocation were excluded.

RESULTS

A total of 132 studies involving 43,869 knee dislocations were analyzed. The majority of patients were young adult males, with high-velocity trauma, particularly motor vehicle accidents, being the most common cause. Substance use and alcohol involvement were commonly reported. The predominant KD types were KD III (54.8 %) and KD IV (20.5 %). Meniscal tears were observed in over 50 % of cases, while cartilage injuries were present in 26.7 %. Neurovascular complications were significant, with popliteal artery injuries in 7.8 % and peroneal nerve injuries in 15.3 % of patients. Acute ligament repairs (64.2 %) were more common than delayed repairs (35.8 %), although the average time to repair was 56.1 days. Complications included amputations (2.3 %), fatalities (1.9 %), compartment syndrome (2.7 %), deep infection (5.3 %), and heterotopic ossification (21.6 %). Despite these severe injuries, a substantial loss to follow-up (19 %) and underreporting of functional outcomes were noted, limiting the comprehensive assessment of long-term recovery. A notable percentage of patients did not return to work or sports, with many requiring a change in profession due to their injuries, but these outcomes were only reported in 10 or fewer studies.

CONCLUSION

This study highlights the significant gaps in understanding the treatment strategies, financial burden, and long-term outcomes of knee dislocations. The incomplete data, particularly the high loss to follow-up rates and underreported functional outcomes, hinders the ability to make comprehensive assessments. Available results should thusly be interpreted with an understanding of the gaps in data, however return to sport and prior employment is often not achieved. Additionally, the potential influence of socioeconomic factors and substance abuse on treatment decisions and outcomes remains inadequately explored. Future research should focus on these areas to improve the management and prognosis of patients with knee dislocations, ensuring more accurate and thorough evaluations of long-term recovery and quality of life.

A Modern-Day Algorithm for the Treatment of Multi-Ligament Knee Injuries

Introduction

Multiligament knee injuries (MLKI) are rare and complex, significantly impacting long-term outcomes, with risks of osteoarthritis, joint stiffness, and reduced activity levels.

Objective

To explore the evolution of MLKI treatment protocols, comparing historical and modern approaches, and to present a patient-tailored, preservation-first algorithm.

Methods

This article reviews the literature on MLKI management, focusing on surgical timing, techniques, and rehabilitation protocols. The proposed algorithm categorizes MLKIs based on tear location and tissue quality, incorporating options, such as primary ligament repair, augmentation, and reconstruction.

Results

The modern preservation-first algorithm provides a tailored approach to MLKI treatment, addressing the complexity and heterogeneity of these injuries, and aims to mitigate risks like postoperative arthrofibrosis.

Conclusion

MLKI management remains complex and controversial. The presented algorithm offers a structured, individualized treatment strategy that integrates modern surgical and rehabilitation advancements.

Vascular Injuries in Multiligament Knee Injuries (MLKIs)

Purpose

Vascular injuries are rarely associated with severe knee injuries; nonetheless, it is imperative to efficiently detect this condition and plan for either immediate or definitive treatment at later stages. The diagnosis and management of multiligament knee injuries still present unresolved issues, particularly in the early detection of vascular issues and the sequential stabilisation of ligaments. High-energy trauma is a frequently encountered cause, however, even low-energy trauma in those who are morbidly obese might pose a significant risk. Advancements in detection and management methods have greatly decreased the occurrence of vascular complications and amputation rates over time. MLKIs after transient knee dislocations are frequently misdiagnosed for vascular injuries, underscoring the necessity for improved diagnostic techniques to avoid avoidable amputations.

Methods

This article is a new conceptual review of vascular injuries associated with MLKIs. It provides a full overview of these conditions and includes a review of the most recent literature. We have included pertinent citations from the literature, together with suggestions derived from the latest studies. This review article had additional evaluation by proficient specialists with commendable outcomes and more than a decade of expertise in surgical techniques.

Results

This article offers a detailed overview of orthopaedic management, including new definitions and summaries of the causes, evaluation of patients, clinical assessment, identification of vascular injuries, and initial management in patients with vascular impairment following major limb and joint injuries (MLKIs).

Conclusion

MLKIs (patients with lower limb ischaemia) who have vascular damage necessitate meticulous physical assessment and sophisticated treatments in order to decrease amputation rates. Prompt identification and timely treatment of vascular lesions, namely in the popliteal artery, can substantially reduce the occurrence of amputations. Emerging research suggests that there is a heightened risk in low-energy situations, particularly amongst individuals who are extremely obese. Progress in vascular intervention has led to a reduction in amputation rates, whilst the implementation of new guidelines has enhanced identification. Thorough patient assessment is essential, utilising physical examinations and imaging techniques such as Computed tomography angiography, magnetic resonance angiography (CTA or MRA) to guide treatment decisions. MRA, in particular, is capable of identifying both vascular and knee structural damage.

Level of Evidence

Level IV, Literature reviews.

Ultrashort Echo Time Quantitative Magnetic Resonance Imaging of the Cruciate Ligaments in Normal Beagles

OBJECTIVE

 The aim of this study was to provide normative ultrashort echo time magnetic resonance imaging (UTE MRI) data of the patellar ligament (PL), cranial cruciate ligament (CrCL) and caudal cruciate ligament (CdCL) in non-lame Beagles.

STUDY DESIGN

 Eight stifles from four subjects obtained immediately postmortem were imaged using UTE MRI in the true sagittal plane. Regions of interest were drawn manually and the total (T2*), short T2* (T2*S) and long T2* (T2*L) values of the signal decay were calculated to evaluate the bound and free water components of the tendon. The T2*S, T2*L and T2* values were compared between the PL, CrCL and CdCL RESULTS:  The mean and standard deviation of T2*S, T2*L and T2* were as follows: 0.54 ± 0.13, 4.65 ± 1.08 and 8.35 ± 0.82 ms for the PL; 0.46 ± 0.14, 5.99 ± 0.52 and 8.88 ± 0.4 ms for the CrCL and 0.41 ± 0.13, 7.06 ± 0.57 and 9.26 ± 0.18 ms for the CdCL. Significant differences were found between the T2*L component of the PL and each CrCL/CdCL and a smaller difference was noted between the T2*L of the CrCL and CdCL (p = 0.05). No difference of the T2*S value was found between any of the ligaments.

CONCLUSION

 Establishing normative UTE data of the canine stifle is valuable for comparison in future studies in which normal and damaged ligaments may be evaluated, particularly in those affected limbs in which no instability is identified on physical examination in which normal and damaged ligaments may be evaluated.

Diagnosis and treatment strategies of the multiligament injured knee: a scoping review

OBJECTIVE

To map the current literature evaluating the diagnosis and treatment of multiligament knee injuries (MLKIs).

DESIGN

Scoping review.

DATA SOURCES

Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews and Arksey and O'Malley frameworks were followed. A three-step search strategy identified relevant published literature comprising studies reporting on at least one aspect in the diagnosis or treatment of MLKI in adults. Data were synthesised to form a descriptive analysis and thematic summary.

RESULTS

Overall, 417 studies were included. There was a substantial chronological increase in the number of studies published per year, with 70% published in the last 12 years. Of included studies, 128 (31%) were narrative reviews, editorials or technical notes with no original data. The majority of studies (n=239, 57%) originated from the USA; only 4 studies (1%) were of level I evidence. Consistent themes of contention included clinical assessment, imaging, operative strategy, timing of surgery and rehabilitation. There was a lack of gender and ethnic diversity reported within patient groups.

CONCLUSIONS

There remains insufficient high-level evidence to support definitive management strategies for MLKI. There is considerable heterogeneity in outcome reporting in current MLKI literature, precluding robust comparison, interpretation and pooling of data. Further research priorities include the development of expert consensus relating to the investigation, surgical management and rehabilitation of MLKI. There is a need for minimum reporting standards for clinical studies evaluating MLKI.

Accuracy of Magnetic Resonance Imaging in the Diagnosis of Multiple Ligament Knee Injuries: A Multicenter Study of 178 Patients

BACKGROUND

Magnetic resonance imaging (MRI) has shown limited diagnostic accuracy for multiple ligament knee injuries (MLKIs), especially posterolateral corner (PLC) injuries.

HYPOTHESIS

The diagnostic accuracy of MRI for MLKIs will only be moderate for some knee structures. Patient-related factors and injury patterns could modify the diagnostic accuracy of MRI.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

All patients with MLKIs surgically treated between January 2014 and December 2020 in the centers participating in the study were reviewed. We recorded sex, age, mechanism of injury, time from injury to MRI, and vascular and neurological associated lesions. Lesions to the anterior cruciate ligament (ACL), posterior cruciate ligament, medial collateral ligament, lateral collateral ligament (LCL), popliteus tendon, popliteofibular ligament, iliotibial band, biceps tendon, medial and lateral meniscus, and articular cartilage from MRI reports and surgical records were also collected. The sensitivity, specificity, positive predictive value, negative predictive value, diagnostic accuracy, diagnostic odds ratio, positive and negative likelihood ratio, and intraclass correlation coefficient of MRI were calculated for each knee structure. With logistic regression, associations between patient and injury characteristics and MRI accuracy were assessed.

RESULTS

A total of 178 patients (127 male; mean age, 33.1 years) were included. High-energy trauma was the most common mechanism of injury (50.6%), followed by sports trauma (38.8%) and low-energy trauma (8.4%). The ACL was the structure with the best diagnostic accuracy, diagnostic odds ratio, and positive predictive value (94.4%, 113.2, and 96.8%, respectively). PLC structures displayed the worst diagnostic accuracy among knee ligaments (popliteus tendon: 76.2%; LCL: 80.3%) and diagnostic odds ratio (popliteus tendon: 9.9; LCL: 17.0; popliteofibular ligament: 17.5). MRI was more reliable in detecting the absence of meniscal and chondral lesions than in identifying them. Logistic regression found that the diagnostic accuracy was affected by the Schenck classification, with higher Schenck grades having worse diagnostic accuracy for peripheral structures (iliotibial band, popliteus tendon, and biceps tendon) and improved diagnostic accuracy for the ACL and posterior cruciate ligament.

CONCLUSION

The diagnostic accuracy of MRI for MLKIs largely varied among knee structures, with many of them at risk of a misdiagnosis, especially PLC, meniscal, and chondral lesions. The severity of MLKIs lowered the diagnostic accuracy of MRI for peripheral structures.

The diagnostic accuracy of MRI for evaluating the posterolateral corner in acute knee dislocation

OBJECTIVE

To investigate the diagnostic performance of preoperative MRI in evaluating posterolateral corner (PLC) structures after acute knee dislocation (KD) and determine the correlation of MRI with operative findings for grading structure integrity.

METHODS

Acute knee (femorotibial) dislocations between 2005 and 2020 with preoperative MRI and surgical posterolateral corner repair were identified from a single academic institution. From MRI, integrity was evaluated for PLC structures: lateral collateral ligament (LCL), popliteus tendon (PT), biceps femoris tendon (BFT), and ligamento-capsular complex (LCC). Frequency of injury to each structure and number of PLC structures torn in each case were tabulated. Diagnostic performance of MRI was determined using surgery as the reference standard. Correlation between MRI and surgery for each PLC structure was determined using kappa.

RESULTS

Thirty-nine KD cases (19 right) in 39 patients (28 male) were included, with mean age of 33 years. Mechanism of injury was as follows: high energy 52%, low energy 38%, ultra-low energy 10%. LCL was most frequently torn, in 95% (37/39) of cases. Most commonly, three of four PLC structures were torn in 54% (21/39) of cases. Diagnostic accuracy of MRI was high for LCL 95%, BFT 87%, PT 82%, and LCC 92%. Correlation between MRI and surgical findings was variable: substantial for BFT, moderate for LCL and PT, and fair for LCC.

CONCLUSION

MRI has high accuracy for detecting tears of posterolateral corner stabilizers in the setting of acute KD. However, for grading structure integrity, the correlation of MRI with surgical findings is variable, ranging from fair to substantial.

KEY POINTS

• In acute knee dislocation, MRI has high diagnostic accuracy for detecting tears of posterolateral corner (PLC) structures. • Preoperative MRI should be considered by orthopedic surgeons when there is clinical concern for posterolateral corner instability following acute knee dislocation. • Although MRI is valuable in the preoperative investigation of knee dislocation, clinical assessment and intraoperative exploration may still be required for definitive diagnosis.

The accuracy of routine knee MR imaging in detection of acute neurovascular injury following multiligamentous knee injury

OBJECTIVE

To assess the accuracy of routine knee MRI in detecting acute popliteal artery and/or common peroneal nerve (CPN) dysfunction following multiligamentous knee injury (MLKI), with correlation of MRI findings to clinical outcome.

MATERIALS AND METHODS

Routine MRI knee examinations in 115 MLKI patients (54/115 with acute neurovascular injury, 61/115 without neurovascular injury) were retrospectively reviewed. Cases were classified by injury mechanism and ligamentous injuries sustained. MRI examinations were reviewed by two readers for vascular (arterial flow void, arterial calibre, intimal flap, perivascular hematoma) and CPN (intraneural T2-hyperintensity, calibre, discontinuity, perineural hematoma) injuries. Accuracy of routine knee MRI in the diagnosis of acute neurovascular injury and correlation of MRI findings to clinical outcome were evaluated.

RESULTS

Patients included 86/115 males, mean age 33 years. The accuracy of MRI in diagnosis of acute CPN injury was 80.6%, 83.6% (readers 1 and 2): sensitivity (78%, 79.7%), specificity (80%, 86.7%), PPV (78%, 82.5%), and NPV (82.7%, 84.4%). Increased intraneural T2 signal showed a significant correlation to acute CPN dysfunction (p < 0.05). MRI was 75%, 69.8% (readers 1 and 2) accurate in detecting acute vascular injury: sensitivity (73.3%, 86.7%), specificity (75.2%, 67.3%), PPV (30.5%, 36.1%), and NPV (95%, 97.1%). No MRI features of vascular injury showed a statistical correlation with clinical outcome. Neurovascular complications were more common in ultra-low-energy injuries and KD-V3L pattern of ligament disruption.

CONCLUSION

Routine MRI is of limited accuracy in assessing vascular complication, but higher accuracy in assessing CPN injury following MLKI. Increased intraneural T2 signal on conventional knee MR imaging shows statistically significant association with clinically documented acute CPN dysfunction following MLKI.

Distal posterolateral corner injury in the setting of multiligament knee injury increases risk of common peroneal palsy

PURPOSE

The purpose of this study was to identify if the location of posterolateral corner (PLC) injury was predictive of clinical common peroneal nerve (CPN) palsy.

METHODS

A retrospective chart review was conducted of patients presenting to our institution with operative PLC injuries. Assessment of concomitant injuries and presence of neurologic injury was completed via chart review and magnetic resonance imaging (MRI) review. A fellowship-trained musculoskeletal radiologist reviewed the PLC injury and categorized it into distal, middle and proximal injuries with or without a biceps femoral avulsion. The CPN was evaluated for signs of displacement or neuritis.

RESULTS

Forty-seven operatively managed patients between 2014 and 2019 (mean age-at-injury 29.5 ± 10.7 years) were included in this study. Eleven (23.4%) total patients presented with a clinical CPN palsy. Distal PLC injuries were significantly associated with CPN palsy [9 (81.8%) patients, (P = 0.041)]. Nine of 11 (81.8%) patients with CPN palsy had biceps femoral avulsion (P = 0.041). Of the patients presenting with CPN palsy, only four (36.4%) patients experienced complete neurologic recovery. Three of 7 patients (43%) with an intact CPN had full resolution of their clinically complete CPN palsy at the time of follow-up (482 ± 357 days). All patients presenting with a CPN palsy also had a complete anterior cruciate ligament (ACL) rupture in addition to a PLC injury (P = 0.009), with or without a posterior cruciate ligament (PCL) injury. No patient presenting with an isolated pattern of PCL-PLC injury (those without ACL tears) had a clinical CPN palsy.

CONCLUSION

Distal PLC injuries have a strong association with clinical CPN palsy, with suboptimal resolution in the initial post-operative period. Specifically, the presence of a biceps femoris avulsion injury was highly associated with a clinical CPN palsy. Additionally, CPN palsy in the context of PLC injury has a strong association with concomitant ACL injury. Furthermore, the relative rates of involvement of the ACL vs. PCL suggest that specific injury mechanism may have an important role in CPN palsy.

LEVEL OF EVIDENCE

IV.

Use of Magnetic Resonance Imaging for Orthopedic Trauma and Infection in the Emergency Department

Conditions affecting the musculoskeletal system constitute a significant portion of medical emergencies in the United States, with traumatic injury and infection being two of the most common etiologies. Although physical examination and plain radiographs are often sufficient to guide diagnosis and treatment, there are myriad traumatic and infectious pathologies that are commonly missed or simply not detectable on plain radiographs. Advanced imaging is subsequently warranted for additional workup.Magnetic resonance imaging (MRI) has become an increasingly used imaging modality for musculoskeletal complaints in the emergency department due to its superior visualization of soft tissues, focal edematous changes, and occult osseous insults often not visible on plain radiographs. Although multiple studies have evaluated its utility in the workup of emergency musculoskeletal complaints, there remains a dearth of literature examining the use of MRI for certain occult diagnoses.Radiologists, emergency clinicians, and orthopedic surgeons must be knowledgeable of the indications for MRI in the emergency setting, as delayed diagnosis may contribute to increased morbidity and possibly mortality. This review summarizes the use of MRI in diagnoses relating to trauma or infection among patients presenting to the emergency department with a musculoskeletal complaint.

Diagnostic Performance of Magnetic Resonance Imaging for Detecting Meniscal Ramp Lesions in Patients With Anterior Cruciate Ligament Tears: A Systematic Review and Meta-analysis

BACKGROUND

The clinical importance of meniscal ramp lesions in patients with anterior cruciate ligament (ACL) tear has emerged as a major issue. However, the diagnostic accuracy of magnetic resonance imaging (MRI) for detecting ramp lesions has a wide range.

PURPOSE

To perform a systematic review and meta-analysis of the diagnostic performance of MRI for diagnosing ramp lesion in patients with ACL tear.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A literature search of PubMed, EMBASE, and the Cochrane Library was performed based on the revised guidelines for the PRISMA DTA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses of Diagnostic Accuracy Studies) statement. Diagnostic performance studies using MRI as the index test and arthroscopy as the reference standard for ramp lesion were included. Bivariate and hierarchical summary receiver operating characteristic modeling was used to evaluate the diagnostic performance. Meta-regression analyses were performed to identify potential sources of heterogeneity.

RESULTS

The review and meta-analysis included 9 studies from 8 articles (883 patients with ACL tear and reconstruction). The summary sensitivity, summary specificity, and area under the hierarchical summary receiver operating characteristic for ramp lesion were 0.71 (95% CI, 0.59-0.81), 0.94 (95% CI, 0.88-0.97), and 0.90 (95% CI, 0.87-0.92), respectively. Among the potential covariates, magnet strength (P < .01), patient knee position (P = .04), and MRI interpreter (P = .04) were associated with heterogeneity in terms of sensitivity, whereas magnet strength (P = .03) was associated with heterogeneity in terms of specificity.

CONCLUSION

MRI demonstrated moderate sensitivity and excellent specificity for diagnosing ramp lesion. Routine arthroscopic assessment is recommended for the presence of ramp lesion, regardless of whether it is suspected on MRI. Further clinicoradiological studies of diagnostic algorithms are needed for identifying ramp lesion, including high-resolution MRI with appropriate knee position.

ACR Appropriateness Criteria® Acute Trauma to the Knee

Acute trauma to the knee is a common presentation seen in the emergency department. After a routine clinical examination, imaging is frequently performed to facilitate the diagnosis and almost always starts with radiographs. If clinically indicated, advanced cross-sectional imaging may then be performed for further evaluation. CT is often performed for preoperative planning of the complex tibial plateau and distal femur fractures. Currently, MRI is the study of choice for evaluation of bone marrow, internal derangements, and other soft-tissue injuries about the knee joint. In patients with knee dislocations, MR angiography may be performed simultaneously with MRI for evaluation of internal derangements and vascular injuries with less morbidity compared to conventional angiography. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Lariat sign: An MRI finding associated with common peroneal nerve rupture

Traumatic knee dislocation represents a catastrophic orthopedic injury with potentially devastating vascular and neurologic injuries. We report a case of common peroneal nerve rupture sustained during a knee dislocation with novel radiographic findings that we describe as a lariat sign. At the site of rupture, the distal nerve loops back on itself forming a lasso shape or lariat. This thickened nerve's abnormal course should not be misinterpreted as a vessel.

How sensitive and specific is 1.5 Tesla MRI for diagnosing injuries in patients with knee dislocation?

PURPOSE

The purpose of this study was to assess the sensitivity and specificity of 1.5 T magnetic resonance imaging (MRI) in diagnosing and identifying the specific injury pattern in patients with knee dislocation. The hypothesis was that the sensitivity and specificity are low in patients with posterolateral corner injury and/or PCL tear.

METHODS

A retrospective study was performed on 38 patients (m:f = 29:9, mean age ± SD 34.3 ± 14.0) with traumatic knee dislocation, who underwent 1.5 T MRI prior to surgery. MRI scans were analysed by a musculoskeletal radiologist, and the presence and type of tears to ligaments, tendons and meniscus or bone were recorded. Comparison was made with the intraoperative findings from the surgical records using the same reporting scheme. The agreement between MRI and surgical findings was assessed using kappa statistics, and the sensitivity and specificity were calculated.

RESULTS

In patients with knee dislocation, MRI was found to have low sensitivity (25-38 %) but high specificity (94-97 %) for diagnosing injury to the posterolateral corner. There was high sensitivity in the diagnosis of tears in the cruciate and collateral ligaments (97-100 %); the specificity, however, was lower (50-67 %). The diagnosis of meniscal injury showed low sensitivity (36-56 %) and moderate specificity (69-83 %).

CONCLUSIONS

MRI is a sensitive measure of cruciate and collateral ligament injury in acute knee dislocation; however, it does not reliably diagnose injury to the posterolateral corner or meniscus, and therefore, a higher index of suspicion is required during arthroscopy to prevent misdiagnosis which could affect long-term clinical outcome.

LEVEL OF EVIDENCE

Diagnostic study, Level II.

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.

Pediatric Knee Dislocations and Physeal Fractures About the Knee

Given the high incidence of vascular and neurologic injury associated with pediatric knee dislocations and displaced physeal injuries about the knee, a thorough understanding of the clinical and radiographic signs associated with these injuries, relevant anatomy, workup, reduction techniques, and surgical management is crucial. A higher incidence of these injuries in children is anticipated because of increased participation in high-energy activities that result in contact or collision during sports or recreation. Complications, such as vascular and nerve injuries and compartment syndrome, can be diagnosed early in the workup to prevent catastrophic outcomes. The clinical examination should include evaluation of the motor and sensory status of the limb, palpation of pulses, and measurement of ankle brachial indices. Radiographic examination should include plain radiography and supplemental advanced imaging, if indicated. Vascular imaging or expert consultation should be considered when the pulse or ankle brachial index is abnormal on clinical examination. Selection of nonsurgical or surgical treatment depends on the fracture pattern and stability.

Radiological assessment of irreducible posterolateral knee subluxation after dislocation due to interposition of the vastus medialis: a case report

Knee dislocation is a serious and relatively uncommon traumatism that every emergency room is supposed to diagnose and treat rapidly. Most of the time these dislocations reduce spontaneously or with closed reduction. If a subluxation persists, an incarceration of soft tissue in the joint must be suspected. Irreducible knee subluxations after dislocation are rare entities better described in the orthopaedic than in the radiological literature. However, the initial radiological assessment is an important tool to obtain the correct diagnosis, to detect neurovascular complications, and to plan the most suitable treatment. In cases of delayed diagnosis, the functional prognosis of the joint and even the limb may be seriously compromised primarily because of vascular lesions. Thereby, vascular imaging is essential in cases of dislocation of the knee, and we will discuss the role of angiography and the more recent use of computed tomography angiography or magnetic resonance angiography. Our patient presented with an irreducible knee subluxation due to interposition of the vastus medialis, and we will review the classical clinical presentation and 'do not miss' imaging findings on conventional radiography, computed tomography angiography, and magnetic resonance imaging. Finally, we will also report the classical imaging pathway indicated in knee dislocation, with a special emphasis on the irreducible form.

Acute and chronic menisco-capsular separation in the young athlete: diagnosis, treatment and results in thirty seven consecutive patients

PURPOSE

Menisco-capsular separation (MCS) is an avulsion type of injury of the medial and/or lateral meniscus and is defined as detachment of the meniscus from its capsular attachment. The aims of this study were to show the results of arthroscopic all-inside menisco-capsular repair in a large number of consecutive patients with acute or chronic MCS, emphasise the advantages of this safe treatment option and stress the superiority of the treatment on the basis of thorough physical examination of the knee joint over magnetic resonance imaging (MRI) diagnosis in MCS.

METHODS

We evaluated data of patients treated between October 2011 and July 2012. Inclusion and exclusion criteria were defined and demographic variables evaluated. All patients were examined physically and with MRI. Knee arthroscopy was performed and the MCS repaired through all-inside menisco-capsular repair. Postoperative treatment was standardised. Patients were followed up for at least 24 weeks.

RESULTS

Thirty-seven athletes (12 women, 25 men) were evaluated. Only in six patients was MCS detected on MRI. In all patients, MCS was diagnosed via physical examination. Arthroscopic treatment led to significant (p < 0.01) improvement. There were no complications reported postoperatively.

CONCLUSION

Isolated MCS is not as rare a meniscus pathology after trauma in young athletes as could be expected after reviewing current literature. It is occult on MRI scans in most of the cases and should therefor be taken into consideration in patients with acute or chronic tenderness at the level of the joint line and negative MRI scans. Thorough physical examination has higher diagnostic value than MRI alone, as shown in this study. Treatment of MCS using all-inside nonabsorbable sutures, as described in this study using Ultra FasT Fix®, is effective if performed by an experienced surgeon.

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.

Relevancy and reproducibility of magnetic resonance imaging (MRI) interpretation in multiple-ligament injuries and dislocations of the knee

INTRODUCTION

After multiple-ligament injuries and dislocations of the knee, clinical assessment of the soft tissues is difficult and MRI is generally performed.

HYPOTHESIS

MRI is a reliable examination, providing a precise and reproducible assessment of soft-tissue lesions after multiple-ligament injuries or dislocations of the knee.

MATERIALS AND METHODS

Forty patients presenting multiple-ligament lesions of the knee were included in this multicenter prospective study. All had an MRI of the knee in the 48 h following their accident. Thirty-four patients were treated surgically. A 17-item standardized interpretation guide was created. Intraobserver reproducibility was assessed by comparing the interpretations of five surgeons at two different times 3 weeks apart. Interobserver reproducibility was evaluated by comparing the results of the interpretations of 40 MRIs performed by three pairs of surgeons. The relevance of the MRI interpretations was determined by comparing the results of the surgeons to those of a radiologist and with the data from the surgical reports.

RESULTS

The overall intraobserver and interobserver agreement was low. Comparing the surgeon's results with the radiologist's results and the surgical data, the agreement was low.

DISCUSSION

After multiple-ligament injuries and dislocations of the knee, a precise diagnosis is necessary. This study provides an isolated demonstration of the lack of precision and reproducibility of MRI interpretations for the diagnosis of the lesion's topography. MRI should be integrated into a complete assessment with a precise clinical exam and stress X-rays.

LEVEL OF EVIDENCE

Level IV, prospective case-control study.

ACR appropriateness criteria(®) acute trauma to the knee

There are more than 1 million visits to the ER annually in the United States for acute knee trauma. Many of these are twisting injuries in young patients who can walk and bear weight, and emergent radiography is not required. Several clinical decision rules have been devised that can considerably reduce the number of radiographic studies ordered without missing a clinically significant fracture. Although fractures are seen on only 5% of emergency department knee radiographs, 86% of knee fractures result from blunt trauma. In patients with falls or twisting injuries who have focal tenderness, effusion, or inability to bear weight, radiography should be the first imaging study performed. If radiography shows no fracture, MRI is best for evaluating for a suspected meniscal or ligament tear or patellar dislocation. Patients with knee dislocation should undergo radiography and MRI, as well as fluoroscopic angiography, CT angiography, or MR angiography. The ACR Appropriateness Criteria(®) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Small medial meniscocapsular separations: a potential cause of chronic medial-side knee pain

PURPOSE

To describe clinical characteristics, surgical findings, and functional outcome after arthroscopic repair of a unique type of meniscocapsular separation.

METHODS

We retrospectively reviewed office charts, magnetic resonance imaging (MRI) scans, operative reports, and arthroscopic images of 6 patients who underwent surgery between January 2007 and May 2009, in whom a medial meniscocapsular separation measuring less than 5 mm in length was identified and treated. Inclusion criteria were medial-side knee pain unresponsive to nonoperative management, negative MRI findings, and an isolated meniscocapsular separation injury detected on arthroscopy and repaired with 1 stitch. Patients were contacted and completed questionnaires that included subjective International Knee Documentation Committee, Tegner, and Marx scores.

RESULTS

Of the 6 patients, 5 were female patients aged 14 to 18 years who were involved in sports. All patients recalled an acute twisting knee injury. Symptoms were related mainly to sports and were absent or very minimal during activities of daily living. On physical examination, the medial joint line was tender in all patients, whereas medial-side knee discomfort while squatting (i.e., baseball catcher's position) and McMurray tests were positive only in some. The negative MRI scans used a 3-T magnet in 5 cases and a 1.5-T magnet in 1 case. The duration of symptoms from injury to surgery was between 6 months and 9 years in 5 cases. On arthroscopy, all patients had a medial meniscocapsular separation measuring less than 5 mm in length that was identified when the tip of the arthroscopic probe was inserted into the lesion. This was repaired with a single all-inside stitch. The mean latest follow-up was 31 months (range, 15 to 38 months). The mean subjective International Knee Documentation Committee score was 87 at latest follow-up. Tegner and Marx scores showed that after surgery, 5 patients regained their preinjury level of activity.

CONCLUSIONS

Meniscocapsular separation can involve a segment of less than 5 mm in length, be occult on MRI, be challenging to visualize on arthroscopy, and lead to chronic medial-side knee pain. Critical evaluation with a history, physical examination, and careful arthroscopic inspection of the medial meniscus can lead to appropriate treatment with a good to excellent outcome after repair.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

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.

Common peroneal nerve palsy complicating knee dislocation and bicruciate ligaments tears

INTRODUCTION

The occurrence rate of common peroneal nerve (CPN) palsy associated with knee dislocation or bicruciate ligament injury ranges from 10 to 40%. The present study sought first to describe the anatomic lesions encountered and their associated prognoses and second to recommend adequate treatment strategy based on a prospective multicenter observational series of knee ligament trauma cases.

MATERIAL AND METHODS

Twelve out of 67 knees treated for dislocation or bicruciate lesion presented associated CPN palsy: two females, 10 males; mean age, 32 years. Four sports injuries,three traffic accidents and five other etiologies led to seven complete dislocations and five bicruciate ruptures. Four cases involved associated popliteal artery laceration ischemia; one of the dislocations was open. Paralysis was total in eight cases and partial in four. There were two complete ruptures, three contusions with CPN in continuity stretch lesions and three macroscopically normal aspects.

RESULTS

At a minimum 1 year's follow-up, regardless of the initial surgical technique performed,recovery was complete in six cases, partial (in terms of motor function) in one and absent in five. Without specific CPN surgery, spontaneous recovery was partial in one case, complete in two and absent in none. Following simple emergency or secondary neurolysis, remission was total in four cases and absent in one. Three nerve grafts were all associated with non-recovery.

DISCUSSION

The present results agree with literature findings. Palsy rates varied with trauma circumstances and departmental recruitment. Neurologic impairment was commensurate to ligamentary damages. The anatomic status of the CPN, subjected to violent traction by dislocation,was the most significant prognostic factor for neurologic recovery. In about 25% of dislocations, contusion-elongation over several centimeters was associated with as poor a prognosis as total rupture. CPN neurolysis is recommended when early clinical and EMG recovery fails to progress and/or in case of lateral ligamentary reconstruction. Possible peripheral nerve impairment needs to be included in the overall functional assessment of treatment for severe ligaments injuries and knee dislocation.

LEVEL OF EVIDENCE

Level IV, prospective study.

Vascular lesions associated with bicruciate and knee dislocation ligamentous injury

INTRODUCTION

The incidence of associated vascular lesions in biligamentous cruciate injuries of the knee ranges from 16 to 64%, with a mean rate of 30%. Treatment of ischemic vascular lesions associated with ligaments injury is well established, comprising emergency arterial vascular repair, most of the times combined to external fixation. In the absence of clinical symptoms of vascular lesion, some authors recommend systematically performing arteriography, while others advocate selectively prescribing this examination in doubtful clinical situations. The present study analyzed data extracted from the prospective series of the 2008 SOFCOT Symposium (dedicated to management of bicruciate knee lesions) and from an analysis of the literature, with emphasis on developing a diagnostic strategy for vascular lesions associated with bicruciate lesions.

MATERIAL AND METHODS

This multicenter prospective study included all patients treated in the reference centers for dislocation or bicruciate lesion of the knee between January 2007 and January 2008. All patients underwent early objective vascular imaging.

RESULTS

Sixty-seven patients were included. Mean dislocation reduction time was 2 hrs 45 min (max, 21 hrs). There were nine vascular lesions (12%). Absence of vascular lesion could be confirmed in 58 of the 59 patients exhibiting presence of peripheral pulses at initial examination. In one case, a vascular lesion was found on early imaging, but with no clinical consequence. In all eight cases with associated clinical pulse abnormality, complementary vascular check-up confirmed the presence of a vascular lesion. Angioscan induced no error of vascular assessment in this series, with no false positives or false negatives. One patient underwent amputation for critical ischemia. Three patients had vascular surgical treatment, two not undergoing secondary ligament surgery. Four of the five patients whose vascular lesion was conservatively managed by simple observation were able to undergo the scheduled treatment for their ligament lesions.

DISCUSSION

At initial examination, it is essential to look for the peripheral pulse. In case of ischemic syndrome, the priority is a revascularization procedure associated to intraoperative arteriography. In case of abnormal pulse without obvious ischemia, emergency imaging (usually arteriogram or angioscan) is essential. Where there is no initial clinical vascular abnormality, good practice is less clearly cut. Initially, present pulses are found in a mean 30% (17-55%) of cases of popliteal artery lesion, according to the series. Different authors draw diverging conclusions from this fact. For some, the absence of frank abnormality on clinical examination is sufficient to exclude not any possible anatomic vascular lesion but any vascular lesion requiring surgery. However, even without pulse abnormality, we consider systematic imaging to be justified, partly by the difficulty of ensuring strict monitoring, and partly by the decompensation risk of clinically asymptomatic intimal lesions during the ligament surgery under consideration in most cases. Although many authors cling to the dogma of late emergency arteriography, recent reports argue against this attitude. Angio-MRI has good diagnostic value, but in practice is difficult to obtain in emergency. We would rather advocate angioscanning, which is easily available in emergency and does not incur the risk of local complication associated with arteriography.

Extensor mechanism injuries in tibiofemoral dislocations

OBJECTIVE

The purpose of this study is to evaluate the incidence, location, and associated findings of extensor mechanism injuries in the setting of tibiofemoral knee dislocations.

METHODS

A retrospective search for patients with previous knee dislocation and MRI of the knee was made during a 5-year period. Images were evaluated for abnormalities commonly seen in patellar instability. Patellar and quadriceps tendon integrity were also evaluated.

RESULTS

A total of 14 patients were included in the study. Medial patellofemoral ligament injuries were identified in 10 patients (71%) with tibiofemoral dislocation. As in patients with previous patellar dislocation, medial patellofemoral ligament injuries commonly occurred at the femoral attachment of the ligament. Medial patellofemoral ligament injuries correlated well with vastus medialis oblique elevation. Patellar tendon injuries were less common identified in only 5 patients (36%).

CONCLUSIONS

Medial patellofemoral ligament injuries can be associated with tibiofemoral knee dislocations. In addition, patellar tendon injuries can also occur, although these are usually partial tears.

Neurologic and vascular injuries associated with knee ligament injuries

BACKGROUND

Multiple ligament knee injuries are commonly associated with neurovascular complications such as popliteal artery, common peroneal nerve, and tibial nerve injuries.

HYPOTHESIS

While the importance of identifying these complications in association with bicruciate and triligamentous injuries has been well established, it is important to recognize that any biligamentous and some single ligament knee injuries present with neurological and vascular complications as well.

STUDY DESIGN

Literature review.

CONCLUSION

Popliteal artery injuries require immediate intervention to help prevent limb loss. Peroneal and tibial nerve injuries can be a significant cause of morbidity and, therefore, require an understanding of their natural history, anatomy, and pathophysiologic implications to maximize functionality.

CLINICAL RELEVANCE

This review explores the types, mechanisms, and classifications of common neurovascular complications of knee ligament injuries, discusses their diagnosis, and reviews the therapeutic options available to optimize patient outcomes.

[Traumatic knee dislocation with popliteal vascular disruption: retrospective study of 14 cases]

PURPOSE OF THE STUDY

Complex femorotibial dislocation of the knee joint generally results from high-energy trauma caused by a traffic or a contact sport accident. Besides disruption of the cruciate ligaments, in 10-25% of patients present concomitant palsy of the common peroneal nerve and more rarely disruption of the popliteal artery. The purpose of this work was to assess outcome in a monocentric consecutive series of knee dislocations with ischemia due to disruption of the popliteal artery and to focus on specific aspects of management.

MATERIAL AND METHODS

This retrospective series included eleven men and three women, aged 18 to 74 years (mean 47 years). The right knee was injured in five and the left knee in six. Trauma resulted from a farm accident in six patients, fall from a high level in two, a traffic accident in three and a skiing accident (fall) in one. Two other patients with morbid obesity were fall victims. Nine patients had a single injury, two presented an associated serious head injury, one a severe chest injury, and one multiple trauma with coma, chest contusion, and abdominal lesions. One patient had a fracture of the distal femur with associated ischemia. Five knee dislocations were open with a popliteal wound for three and a posteromedial wound for two. Four patients presented total sciatic nerve palsy and nine palsy of the common peroneal nerve. The dislocation was documented in ten cases: lateral (n=1), anterior (n=4), posterior (n=5). For four patients, the dislocation had been reduced during pre-hospital care. Preoperative arteriography was available for eight patients and confirmed the disruption of the popliteal artery; the diagnosis was obvious in six other patients who were directed immediately to the operative theatre without pre-operative imaging. Revascularization was achieved with a upper popliteal-lower popliteal bypass using an inverted saphenous graft. The graft was harvested from the homolateral greater saphenous vein in eight patients and the contralateral vein in six. On average, limb revascularization was achieved after 10.07 hours ischemia. Intravenous heparin was instituted for 810 days followed by low-molecular-weight heparin. The dislocation was stabilized by a femorotibial fixator in nine patients and a cruropedious cast in five. An incision was made in the anterolateral and posterior leg compartments in twelve patients. A revision procedure was necessary on day one in one patient because of recurrent ischemia; a second bypass using an autologous venous graft was successful. One other 75-year-old patient also presented recurrent ischemia on day five; the bypass was reconstructed but the patient died from multiple injuries. Seven thin skin grafts were used to cover the aponeurotomy surfaces. Mean duration of the external fixator was 3.4 months. The five patients treated with a plaster case were immobilized for 2.7 months on average. Ligament repair was performed in three patients (one lateral reconstruction and one double reconstruction of the central pivot for the two others). A total prosthesis with a rotating hinge was implanted in two patients aged 67 and 74 years after removal of the external fixator at six and seven months. Failure of the ligament repair also led to arthroplasty in a third patient.

RESULTS

Blood supply to the lower limb was successfully restored as proven by the renewed coloration of the teguments and-or presence of distal pulses in 13 patients. Transient acute renal failure required dialysis in one patient. Four patients developed pin track discharges and there was one case of septic arthritis of the knee joint which was cured after arthrotomy for wash-out and adapted antibiotics. Outcome was assessed a minimum 18 months follow-up (average 22 months) for the 13 survivors. The three sciatic palsies recovered partially at five and six months in the tibial territory but with persistent paralysis in the territory of the common peroneal nerve. The nine cases of common peroneal nerve palsy noted initially regressed completely or nearly completely in three patients, partially in three and remained unchanged in three. The results were assessed as a function of the final knee procedure: outcome was satisfactory for the patients with a total knee arthroplasty. Outcome of the three ligamentoplasties was good in one, fair in one, and a failure in one (revision arthroplasty). Patients treated by immobilization without a second surgical procedure complained of joint instability with a variable clinical impact; their knee retained active flexion greater than 90 degrees and complete extension.

DISCUSSION

An analysis of the literature and the critical review of our clinical experience was conducted to propose a coherent therapeutic attitude for patients presenting this type of trauma. The prevalence of disruption of the popliteal vascular supply in patients with knee dislocation is between 4 and 20%. The rate is closely related to that of injury to nerves and soft tissue. Ischemia should be immediately suspected in all cases of knee dislocation. The pedious and tibial pulses must be carefully noted before and after reduction of the dislocation to determine whether or not there is an organic arterial lesion. If the pulses are absent initially, they should be expected to reappear strong, rapidly and permanently after reduction. Otherwise, arteriography should be performed. Dislocation stretches the artery between two points of relative anchorage in the adductor ring and the soleus arcade to the point of rupture. Repair requires a bypass between the upper popliteal artery and the tibioperoneal trunk using an inverted saphenous graft because the walls are torn over several centimeters. The traumatology and vascular surgical teams must work in concert from the beginning of the surgical work-up in order to establish a coherent operative strategy founded on primary reduction of the dislocation, installation of a fixator and then vascular repair and aponeurotomy incisions. It would be preferable to wait until the bypass is proven patent and wound healing is complete before proposing ligament repair. This should be done after a precise anatomic work-up to assess each ligament lesion. Bony avulsion or simple disinsertion can however be repaired in the emergency setting at the time of the bypass as well as any ligament rupture which is obvious and-or situated on the medial collateral approach. Secondarily, elements of the central pivot can be repaired in young patients with an important functional demand. Arthroplasty is not warranted except in the elderly patient. Dissection of the popliteal fossa or debridement of the wound enables a careful anatomic assessment of the nerve trunks. In the event of a peroneal nerve disruption, it is advisable to fix the nerve ends to avoid retraction. Beyond three months without clinical or electromyography recovery, surgical exploration is indicated. In the event more than 15 cm is lost, there is no hope for a successful graft. Complete knee dislocation is extremely rare. It can be caused by high-energy trauma associated with several ligament ruptures, particularly rupture of the central pivot observed in 10-25% of cases with common peroneal nerve palsy. Compression, contusion or disruption of the popliteal artery is very rarely caused by the displacement of the femur or the tibia. Limb survival may be compromised. Mandatory emergency restoration of blood supply will modify immediate and subsequent surgical strategies. There has not however been any study exclusively devoted to double joint and vascular involvement. Our objective was to present a critical retrospective analysis of a consecutive series of knee dislocations with ischemia due to disruption of the common popliteal artery treated in a single center and to describe the specific features of management strategies for a coherent diagnostic and therapeutic approach.

[Dislocation and fractures around the knee with popliteal artery injury: A retrospective analysis of 54 cases]

A retrospective multicentric series of 54 cases of knee trauma with acute ischemia by popliteal artery injury were analyzed. These high-energy traumas involved 25 dislocations and 29 fractures, 11 involving distal femur, 15 the proximal tibia and 3 a floating knee. There were 45 men and 7 women, mean age 42 years. Thirty-three patients suffered multiple injuries. The knee injury was open in 25 cases and associated with sciatic paralysis in 32. Vascular repair was almost always achieved with bypass surgery. An external fixator was used in 39 patients. Vascular repair was unsuccessful in three cases requiring amputation, all three cases involving fractures. There were also six secondary amputations due to muscle necrosis or septic nonunion. The rate of complete recovery of the sciatic was 25%. The rate of nonunion was 37%, half due to infection. Outcome assessed at at least one year follow-up was moderate with frequent functional sequelae. The analysis of these results and data reported in the literature provided indications for diagnostic and therapeutic propositions.

Anterior cruciate ligament tears and associated injuries

Anterior cruciate ligament (ACL) tears are a commonly sustained sports injury, often occurring in association with meniscal tears and trauma to other ligamentous structures around the knee. Diagnosis can often be made clinically, but assessment may be difficult in the acute setting when there is a large joint effusion and severe pain. Plain radiographs may detect the presence of a joint effusion and any associated fractures. However, magnetic resonance imaging is vital for assessing acute knee injuries and plays an important role in deciding treatment options and planning surgical intervention. Some of the associated meniscal and ligamentous injuries can be subtle and may easily be overlooked if these structures are not scrutinized closely. This article will discuss the anatomy of the ACL and the mechanisms and initial clinical assessment of ACL injuries, and review the imaging features of ACL tears and some of the associated injuries, including the posterolateral corner structures. These associated injuries have important implications for determining treatment options and subsequent return to athletic activities.

Functional outcome following reconstruction in chronic multiple ligament deficient knees

Multiligament knee injuries are rare but potentially limb-threatening conditions. In this study we aim to evaluate the mid- and long-term functional outcome of patients who underwent arthroscopically assisted multiple ligament reconstruction for chronic multiple knee ligament deficiency. Thirty-five patients (27 males and 8 females) with an average age of 35.1 years (range: 17-60) were included in this study. Follow-up ranged from 12 to 124 months (average: 40.3). On final follow-up patients had a mean loss of extension of 3.1 degrees , while flexion ranged from 95 degrees to 135 degrees (average: 118.4 degrees ). The functional outcome according to Clancy's criteria was excellent in 7 patients (20%), good in 14 (40%), fair in 11 (31.4%), while 3 reconstructions resulted in failure (8.6%). Patients scored an average of 4.03 (range: 1-9) in their Tegner Activity Scale, while their score in Activities of Daily Living Scale of the Knee Outcome Survey ranged from 25 to 98 with an average of 72.7. Sixteen patients returned to sporting activities and all but three returned to work. Early operative treatment of multiple ligament injuries is preferable, as it may allow for anatomic repair instead of reconstruction of ligamentous structures. This study demonstrates though, that even if acute reconstruction has not or could not be performed, reconstruction in chronic multiple ligament deficient knees should be attempted. Although this complex and technically demanding procedure rarely results in a "normal" knee, it offers in most cases very satisfactory stability and a significant improvement in knee function.