The efficacy of magnetic resonance imaging in acute multi-ligament injuries

Treating Combined Anterior Cruciate Ligament and Medial Collateral Ligament Injuries Operatively in the Acute Setting Is Potentially Advantageous

Combined injury of the anterior cruciate ligament (ACL) and medial collateral ligament (MCL) remains among the most common knee injury patterns in orthopaedics. Optimal treatment of grade III MCL injuries is still debated, especially when combined with ACL injury. Most patients with these severe injuries are treated conservatively for at least 6 weeks to allow for MCL healing, followed by delayed ACL reconstruction. Although acute treatment of the MCL was common in the 1970s, postoperative stiffness was frequently reported. Moreover, studies of such treatment failed to show clinical benefits of surgical over conservative treatment, and the MCL exhibited intrinsic healing capacity, leading to the consensus that all MCL injuries are treated conservatively. The current delayed treatment algorithm for ACL-MCL injuries has several disadvantages. First, MCL healing may be incomplete, resulting in residual valgus laxity that places the ACL graft at greater risk of failure. Second, delayed treatment lengthens the overall rehabilitation period, thereby prolonging the presence of atrophy and delaying return to preinjury activity levels. Third, the initial healing period leaves the knee unstable for longer and risks further intra-articular damage. Acute simultaneous surgical treatment of both ligaments has the potential to avoid these shortcomings. This article will review the evolution of treatment of ACL-MCL injuries and explain how it shifted toward the current treatment algorithm. We will (1) discuss why the consensus shifted, (2) discuss the shortcomings of the current treatment plan, (3) discuss the potential advantages of acute simultaneous treatment, and (4) present an overview of the available literature.

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.

Imaging of the medial collateral ligament of the knee: a systematic review

INTRODUCTION

The primary aim of this investigation was to systematically review relevant literature of various imaging modalities (magnetic resonance imaging (MRI), stress radiography and ultrasonography) in the assessment of patients with a medial collateral ligament (MCL) injury.

MATERIALS AND METHODS

A systematic literature review of articles indexed in PubMed and Cochrane library was performed. Original research reporting data associated with medial gapping, surgical, and clinical findings associated with MCL injuries were considered for inclusion. The methodological quality of each inclusion was also assessed using a verified tool.

RESULTS

Twenty-three imaging studies (magnetic resonance imaging (MRI) n = 14; ultrasonography n = 6; radiography n = 3) were ultimately included into the review. A total of 808 injured, and 294 control, knees were assessed. Interobserver reliabilities were reported in radiographic and ultrasonographic investigations with almost perfect agreement. MRI studies demonstrated agreement ranging between substantial to almost perfect. Intraobserver reliability was only reported in radiographic studies pertinent to medial gapping and was found to be almost perfect. Correlation of MRI with clinical findings was moderate to strong (65-92%). Additionally, MRI imaging was more sensitive in the detection of MCL lesions when compared to clinical examination. However, when compared to surgical findings, MRI underestimated the grade of instability in up to 21% of cases. Furthermore, MRI showed relatively inferior performance in the identification of the exact MCL-lesion location when compared to surgical findings. Interestingly, preoperative clinical examination was slightly inferior to stress radiography in the detection of MCL lesions. However, clinical testing under general anaesthesia performed similar to stress radiography. The methodological quality analysis showed a low risk of bias regarding patient selection and index testing in each imaging modality.

CONCLUSION

MRI can reliably diagnose an MCL lesion but demonstrates limitations in its ability to predict the specific lesion location or grade of MCL instability. Ultrasonography is a widely available, radiation free modality, but is rarely used in clinical practice for detecting MCL lesions and clinical or surgical correlates are scarce. Stress radiography findings correlate with surgical findings but clinical correlations are missing in the literature.

LEVEL OF EVIDENCE

IV.

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.

Medial meniscus tears are most prevalent in type I ACL tears, while type I ACL tears only account for 8% of all ACL tears

PURPOSE

This study aimed to assess the distribution of different anterior cruciate ligament (ACL) tear locations in different magnetic resonance imaging (MRI) planes, and to explore the relationships of ACL tear types with both meniscus injuries and bone bruising.

METHODS

A retrospective study was performed in patients under 60 years old who underwent MRI scans in the sagittal and coronal oblique planes of the knee for ACL tears between 2014 and 2020. Patients with reports of chronic tears, partial tears, or prior surgeries were excluded. Tear locations were classified into five types, and the meniscus tear measurement variables included the presence of ramp, root, bucket-handle, and other types of tears. All injuries were confirmed by arthroscopy. Meanwhile, the presence and location of bone bruising were analysed and scored with the Whole-Organ Magnetic Resonance Imaging Score (WORMS) bone bruising subscale.

RESULTS

A total of 291 patients were included. The prevalence rates of type I and type III injuries were 23/291 (7.9%) and 145/291 (49.8%) in the sagittal plane and 22/291 (7.6%) and 179/291 (61.5%) in the oblique coronal plane, respectively. The prevalence of medial meniscus tears with ACL tears was 126/291 (43.3%), while that of lateral meniscus tears with ACL tears was 77/291 (26.5%). The highest prevalence of medial meniscus injury with ACL tears was 15/22 (68.2%) for type I injuries. Bone bruises were located on the lateral femoral center in 125 patients (46%) and on the lateral tibia posterior in 132 patients (48%); the common areas of bone bruising were slightly correlated with type III ACL tears but not correlated with type I ACL tears.

CONCLUSION

The plane in which an MRI scan is performed affects the classification of ACL tears. The tear type is associated with the prevalence of medial meniscus injuries, and medial meniscus tears are most prevalent in type I ACL tears.

LEVEL OF EVIDENCE

IV.

The accuracy of MRI in diagnosing and classifying acute traumatic multiple ligament knee injuries

Background

Magnetic resonance imaging (MRI) is widely used for the evaluation of knee injuries, however, the accuracy of MRI in classifying multiple ligament knee injuries (MLKIs) remains unknown. This study aimed to investigate the accuracy of MRI in diagnosing and classifying acute traumatic MLKIs, we hypothesize that MRI had high accuracy in detecting and classifying MLKIs.

Methods

The clinical data of 97 patients who were diagnosed with acute traumatic MLKIs and managed by multi-ligament reconstruction between 2012 and 2020 were retrospectively reviewed. The MR images were read by two experienced radiologists and results were compared with intraoperative findings, which were considered as the reference for the identification of injured structures. The value of MRI in detecting injuries of anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), lateral collateral ligament (LCL), and meniscus was evaluated by calculating the sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, and kappa coefficients analysis. The value of MRI in classifying MLKIs was evaluated by calculating the agreement between MRI and intraoperative findings.

Results

For detecting the specific injured structures in MLKIs, MRI had high sensitivity (90.7% for ACL, 90.4% for PCL, and moderate specificity (63.6% for ACL, 50% for PCL) in detecting cruciate ligament injuries, moderate sensitivity (79.1% for MCL, 55.6% for LCL) and specificity (46.7% for MCL, 68.4% for LCL) in detecting collateral ligament injuries, fair sensitivity (61.5%) and low specificity (39.4%) in the diagnosis of injuries to the meniscus. For classifying the MIKIs, MRI had a moderate agreement with intraoperative findings in classifying KD-V (kappa value = 0.57), poor agreement in the KD-I (kappa value = 0.39) and KD-IIIM (kappa value = 0.31), meaningless in the KD-II and KD-IIIL (kappa value < 0). The overall agreement between MRI and intraoperative findings in classifying MLKIs was poor (kappa value = 0.23).

Conclusions

MRI is valuable in early detection and diagnosis of acute MLKIs, however, the accuracy of MRI in classifying MLKIs is limited. The management of MLKIs should be based on intraoperative findings, physical examinations, and comprehensive imaging results.

Magnetic Resonance Imaging of the Knee in the Presence of Bridging External Fixation: A Comparative Experimental Evaluation of Four External Fixators, Including Dolphix®

Performing MR investigation on patients instrumented with external fixators is still controversial. The aim of this study is to evaluate the quality of MR imaging of the knee structures in the presence of bridging external fixators. Different cadaveric lower limbs were instrumented with the MR-conditional external fixators Hofmann III (Stryker, Kalamazoo, MI, USA), Large external Fixator (DePuy Synthes, Raynham, MA, USA), XtraFix (Zymmer, Warsaw, IN, USA) and a newer implant of Ketron Peek CA30 and ERGAL 7075 pins, Dolphix^®, (Citieffe, Bologna, Italy). The specimens were MR scanned before and after the instrumentation. The images were subjectively judged by a pool of blinded radiologists and then quantitatively evaluated calculating signal intensity, signal to noise and contrast to noise in the five regions of interest. The area of distortion due to the presence of metallic pins was calculated. All the images were considered equally useful for diagnosis with no differences between devices (p > 0.05). Only few differences in the quantification of images have been detected between groups while the presence of metallic components was the main limit of the procedure. The mean length of the radius of the area of distortion of the pins were 53.17 ± 8.19 mm, 45.07 ± 4.33 mm, 17 ± 5.4 mm and 37.12 ± 10.17 mm per pins provided by Zimmer, Synthes, Citieffe and Stryker, respectively (p = 0.041). The implant of Ketron Peek CA30 and ERGAL 7075 pins showed the smallest distortion area.

Comprehensive Assessment of Medial Knee Joint Instability by Valgus Stress MRI

Standard clinical MRI techniques provide morphologic insights into knee joint pathologies, yet do not allow evaluation of ligament functionality or joint instability. We aimed to study valgus stress MRI, combined with sophisticated image post-processing, in a graded model of medial knee joint injury. To this end, eleven human cadaveric knee joint specimens were subjected to sequential injuries to the superficial medial collateral ligament (sMCL) and the anterior cruciate ligament (ACL). Specimens were imaged in 30° of flexion in the unloaded and loaded configurations (15 kp) and in the intact, partially sMCL-deficient, completely sMCL-deficient, and sMCL- and ACL-deficient conditions using morphologic sequences and a dedicated pressure-controlled loading device. Based on manual segmentations, sophisticated 3D joint models were generated to compute subchondral cortical distances for each condition and configuration. Statistical analysis included appropriate parametric tests. The medial compartment opened gradually as a function of loading and injury, especially anteriorly. Corresponding manual reference measurements by two readers confirmed these findings. Once validated in clinical trials, valgus stress MRI may comprehensively quantify medial compartment opening as a functional imaging surrogate of medial knee joint instability and qualify as an adjunct diagnostic tool in the differential diagnosis, therapeutic decision-making, and monitoring of treatment outcomes.

Efficiency of magnetic resonance imaging for diagnosing unstable ligament injuries around the thumb metacarpophalangeal joint: A comparison to arthroscopy

PURPOSE

This study aimed to assess the accuracy of MRI in identifying ulnar collateral ligament (UCL), radial collateral ligament (RCL), and volar plate (VP) injuries of the metacarpophalangeal joint (MCPJ) of the thumb by comparing with diagnostic arthroscopy.

METHODS

A total of 56 consecutive patients (56 thumbs) who underwent arthroscopy of MCPJ of thumb were enrolled. MRI findings reviewed by consensus reading of two blinded radiologists were compared with arthroscopic examination. Statistical data, including sensitivity, specificity, accuracy, were analyzed. Additionally, the performance characteristics between 3.0-tesla (39 thumbs) and 1.5-tesla (17 thumbs) MRI and acute (≤4 weeks after injury) and chronic (>4 weeks) injuries were compared.

RESULTS

Of the 56 thumbs, 38 thumbs (67.9%) showed complete correspondence between MRI and arthroscopic findings. The sensitivity, specificity and accuracy of MRI for detecting UCL injuries were 78.8%, 87.0%, and 82.1%, respectively. The sensitivity, specificity and accuracy of MRI for detecting RCL injuries were 85.7%, 91.4%, and 85.7%, respectively. The sensitivity, specificity, and accuracy of MRI for detecting VP injuries were 89.5%, 89.2%, and 81.0%, respectively. 3.0-tesla MRI showed higher correspondence with arthroscopic observation (76.9%) than 1.5-tesla MRI (47.1%) (p = 0.028). For acute injuries, 78.4% showed complete correspondence between MRI and arthroscopic findings, whereas 47.4% with chronic injuries revealed complete agreement (p = 0.019).

CONCLUSION

Overall, MRI is moderately effective in evaluating ligamentous lesions around MCPJ of thumb, but MRI is more sensitive in diagnosing acute injuries. Furthermore, 3.0-tesla MRI can provide results with better accuracy for diagnosing ligamentous lesions around MCPJ of thumb. However, the sensitivity and the specificity are not applicable to all ligament injuries, but only the severe one which would agree for surgical options.

MRI of Traumatic Knee Dislocation: A Study to Evaluate Safety and Image Quality for Patients with Knee-Spanning Stabilization Devices

This study evaluated safety and image quality of MRI exams performed for patients with traumatic knee dislocations in knee-spanning stabilization devices. It is an IRB-approved retrospective design with waived informed consent that included 63 patients with traumatic knee dislocation. 56 patients had metallic external fixators, and 7 patients had non-metallic knee immobilizers. 7 patients had bilateral dislocations yielding a total of 70 knee MRIs. 1.5 Tesla MRI exams were performed for all patients who were awake and alert at the time of imaging. All knee-spanning external fixators were considered "MR conditional" by the FDA. The electronic medical record was reviewed for notes from the technologist and nursing staff documenting any patient complaints or adverse events during the MRI exam as required by departmental protocol. Qualitative analysis of the six most frequently performed sequences were independently conducted by 2 musculoskeletal radiologists using a 5-point Likert scale. Overall image quality and select time intervals between the two groups were compared using an independent sample t test and the Mann-Whitney U test, respectively. No adverse events were reported for a 40-minute average estimated patient scan time with the stabilization devices in the MR gantry. Mean values of Likert scale scores were generated from two readers' data for comparison between the external fixation and the immobilizer groups. Most knee MRI exams with external fixators were within diagnostic quality despite artifacts (grade 3). MRI exams generally were of higher diagnostic quality in the immobilizer group than the external fixator group (p < 0.05). The external fixator models included DePuy Synthes, Smith and Nephew, Stryker Hoffman III, Zimmer FastFrame, and Zimmer XtraFix. MRI examinations in patients with external fixators for traumatic knee dislocations can be safely performed under certain conditions and provide diagnostic quality images.

Open approaches for cruciate ligament reconstruction in knee dislocations: A technical note and case series

INTRODUCTION

Arthroscopic surgery is the gold standard for cruciate ligament reconstruction in multi-ligament knee injuries. However, hospitals in limited-resource settings often lack arthroscopic-trained surgeons or equipment. Open approaches for treating knee dislocations can overcome many of these limitations.

METHODOLOGY

This study aims to describe techniques for open approaches in a supine patient to address the cruciate ligaments in multi-ligament knee injuries and to review associated complications and clinical outcomes in a retrospective case series.

RESULTS

Ten patients with multi-ligament knee injuries who had undergone open cruciate ligament reconstruction between July 2016 and November 2018 were retrospectively identified. Open approaches were performed owing to the extravasation of arthroscopy fluid into the posterior compartment (3) or a large traumatic arthrotomy (7). Complications and patient-reported outcomes were analysed. Eight of the 10 patients were followed up at 10 months postoperatively (range, 5-23 months). None had iatrogenic neurovascular damage. Median outcomes scores were: visual analogue scale, 45 (range, 0-100); Knee Injury and Osteoarthritis Outcome Score-Physical Function Short Form, 81.4 (range, 75-100); Lysholm, 85 (range, 67-92).

DISCUSSION

Open approaches were safe and useful in treating cruciate ligaments and should be considered in arthroscopy fluid extraversion and large traumatic arthrotomies.

Longitudinal T2 Mapping and Texture Feature Analysis in the Detection and Monitoring of Experimental Post-Traumatic Cartilage Degeneration

Background: Traumatic cartilage injuries predispose articulating joints to focal cartilage defects and, eventually, posttraumatic osteoarthritis. Current clinical-standard imaging modalities such as morphologic MRI fail to reliably detect cartilage trauma and to monitor associated posttraumatic degenerative changes with oftentimes severe prognostic implications. Quantitative MRI techniques such as T2 mapping are promising in detecting and monitoring such changes yet lack sufficient validation in controlled basic research contexts. Material and Methods: 35 macroscopically intact cartilage samples obtained from total joint replacements were exposed to standardized injurious impaction with low (0.49 J, n = 14) or high (0.98 J, n = 14) energy levels and imaged before and immediately, 24 h, and 72 h after impaction by T2 mapping. Contrast, homogeneity, energy, and variance were quantified as features of texture on each T2 map. Unimpacted controls (n = 7) and histologic assessment served as reference. Results: As a function of impaction energy and time, absolute T2 values, contrast, and variance were significantly increased, while homogeneity and energy were significantly decreased. Conclusion: T2 mapping and texture feature analysis are sensitive diagnostic means to detect and monitor traumatic impaction injuries of cartilage and associated posttraumatic degenerative changes and may be used to assess cartilage after trauma to identify “cartilage at risk”.

Prevalence of ligamentous knee injuries in pedestrian versus motor vehicle accidents

Background

The purpose of this study was to determine the prevalence and characteristics of ligamentous knee injuries and to compare patient demographics, associated injuries and hospital stay to pedestrians who did not sustain a ligamentous knee injury.

Methods

A retrospective review of all adult patients presenting as pedestrians struck by a motor vehicle to a level 1 trauma center over a three-year period was performed. Demographics, length of stay, orthopedic and non-orthopedic traumatic injuries were recorded. Magnetic resonance imaging was reviewed for ligamentous, bony and chondral injuries.

Results

Five hundred thirty-nine patients were included. Sixty-seven (12.4%) patients sustained a total of 84 ligamentous knee injuries. OF these knee injuries that had MRI (55/84), the majority (96%) were multi-ligamentous in nature. Patients with ligamentous knee injury were more likely to also be affected by traumatic brain injury, solid organ injury, cervical and lumbar spine injury, pelvic ring injuries, distal femur fractures, patella fractures, knee dislocations, tibial plateau fractures, tibial pilon fractures, and deep vein thrombosis when compared to patients who did not sustain ligamentous knee injury. Patients who sustained ligamentous knee injury were more likely to require hospital and intensive care admission and had a longer overall hospital stay.

Conclusion

Given the high prevalence of ligamentous knee injuries in this patient population, these patients should be thoroughly evaluated for a ligamentous knee injury. If ligamentous knee injury is suspected, MRI should be considered as a majority of these injuries involved multiple structures. Patients with ligamentous knee injuries often had multi-system injuries with resulting longer hospital stay when compared to those without ligamentous knee injuries.

Common Injuries of the Weekend Athlete

Each year increasing numbers of people participate in a wider variety of athletic endeavors. Unlike previous generations, many patients remain in these activities later into their lives, some well beyond retirement. As the population ages and their activities continue, they are subject to injury of various forms affecting all aspects of their bodies.

External Orthopaedic Implants in the Magnetic Resonance Environment: Current Concepts and Controversies

MRI provides diagnostic three-dimensional imaging and remains extremely important in the diagnosis and management of spinal trauma as well as other acute traumatic injuries, including those of the extremities. The American Society for Testing and Materials has created standards against which all implantable medical devices are tested to ensure safety in an MR environment. Most implantable passive orthopaedic devices can undergo MRI without consequence to the patient. However, the American Society for Testing and Materials has recently updated its terminology resulting in confusion among providers and institutions. Primary safety concerns are radiofrequency-induced heating and magnetically induced torque or displacement. These safety concerns have emerged as a recent source of debate, particularly regarding the imaging of patients with external fixation and cervical immobilization devices in place. Surveys have shown a lack of consensus among radiologists regarding this issue. Having an institutional protocol in place for the imaging of these patients streamlines the diagnosis and early stabilization of certain polytraumatized patients. The purpose of this review is to summarize the pertinent literature as well as the current industry recommendations regarding the safety of commonly used external fixation, cervical immobilization, and traction devices in the MR environment.

Bone bruise in anterior cruciate ligament rupture entails a more severe joint damage affecting joint degenerative progression

PURPOSE

During anterior cruciate ligament (ACL) injury, the large external forces responsible for ligament rupture cause a violent impact between tibial and femoral articular cartilage, which is transferred to bone resulting in bone bruise detectable at MRI. Several aspects remain controversial and await evidence on how this MRI finding should be managed while addressing the ligament lesion. Thus, the aim of the present review was to document the evidence of all available literature on the role of bone bruise associated with ACL lesions.

METHODS

A systematic review of the literature was performed on bone bruise associated with ACL injury. The search was conducted in September 2017 on three medical electronic databases: PubMed, Web of Science, and the Cochrane Collaboration. Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were used. Relevant articles were studied to investigate three main aspects: prevalence and progression of bone bruise associated with ACL lesions, its impact on the knee in terms of lesion severity and joint degeneration progression over time and, finally, the influence of bone bruise on patient prognosis in terms of clinical outcome.

RESULTS

The search identified 415 records and, after an initial screening according to the inclusion/exclusion criteria, 83 papers were used for analysis, involving a total of 10,047 patients. Bone bruise has a high prevalence (78% in the most recent papers), with distinct patterns related to the mechanism of injury. This MRI finding is detectable only in a minority of cases the first few months after trauma, but its presence and persistence have been correlated to a more severe joint damage that may affect the degenerative progression of the entire joint, with recent evidence suggesting possible effects on long-term clinical outcome.

CONCLUSION

This systematic review of the literature documented a growing interest on bone bruise associated with ACL injury, highlighting aspects which could provide to orthopaedic surgeons evidence-based suggestions in terms of clinical relevance when dealing with patients affected by bone bruise following ACL injury. However, prospective long-term studies are needed to better understand the natural history of bone bruise, identifying prognostic factors and targets of specific treatments that should be developed in light of the overall joint derangements accompanying ACL lesions.

LEVELS OF EVIDENCE

IV, Systematic review of level I-IV studies.

Meniscal root tears occur frequently in multi-ligament knee injury and can be predicted by associated MRI injury patterns

PURPOSE

The frequency of meniscal root tears in association with multi-ligament knee injury has not been established but adds to the complexity of surgical reconstruction and may have long-term consequences. Therefore, identifying root tears, on preoperative imaging, is important. The aim of this study was to identify the frequency of meniscal root tears, on preoperative magnetic resonance imaging, following multi-ligament injury and distinguish associated injury patterns that may aid detection.

METHODS

Cases were identified from a prospectively collected institutional database. The magnetic resonance imaging of 188 multi-ligament injuries [median age 31 years (range 16-64)] was retrospectively reviewed by three musculoskeletal radiologists with the presence of meniscal injuries recorded alongside the ligament injury pattern and intra-articular fractures. Assessment of injury pattern was solely made on this imaging.

RESULTS

38 meniscal root injuries were identified in 37 knees (overall frequency = 20.2%; medial = 10.6%; lateral = 9.6%). The frequency of meniscal root tears was not increased in higher grade injuries (21.5% vs. 17.0%, n.s.). Valgus injury patterns were associated with lateral root tears (p < 0.05) and varus patterns were associated with medial root tears (p < 0.05). Further, fractures in the same compartment were associated with both medial and lateral root tears (p < 0.05).

CONCLUSIONS

Meniscal root tears occur more frequently in multi-ligament knee injury than previously reported with isolated anterior cruciate rupture. Root tears can be predicted by ligament injury patterns and fractures sustained (suggestive of a compressive force). In multi-ligament cases, the preoperative magnetic resonance imaging can be used to detect these tears and associated patterns of injury.

LEVEL OF EVIDENCE

IV.

Diagnostic and Management Strategies for Multiligament Knee Injuries: A Critical Analysis Review

Multiligament knee injuries have a strong association with periarticular soft-tissue and neurovascular injuries, which must not be overlooked in the initial evaluation of the patient. Even though magnetic resonance imaging (MRI) is imperative for a complete evaluation of the damaged ligamentous knee restraints, stress radiography aids in establishing the functional consequence of the MRI findings and may assist in directing reconstruction. Although cruciate ligament tears are generally reconstructed, a combined repair-reconstruction approach is most useful for collateral ligaments and extra-articular structures, with incorporation of local tissue into the reconstruction whenever possible. Regardless of the timing and operative technique chosen, patients with multiligament knee injuries are at high risk for complications and long-term disability.

A Prospective, Blinded, Multicenter Clinical Trial to Compare the Efficacy, Accuracy, and Safety of In-Office Diagnostic Arthroscopy With Magnetic Resonance Imaging and Surgical Diagnostic Arthroscopy

PURPOSE

The purpose of this study was to compare the efficacy, accuracy, and safety of in-office diagnostic arthroscopy with magnetic resonance imaging (MRI) and surgical diagnostic arthroscopy.

METHODS

A prospective, blinded, multicenter, clinical trial was performed on 110 patients, ages 18 to 75 years, who presented with knee pain. The study period was April 2012 to April 2013. Each patient underwent a physical examination, an MRI, in-office diagnostic imaging, and a diagnostic arthroscopic examination in the operating room. The attending physician completed clinical report forms comparing the in-office arthroscopic examination and surgical diagnostic arthroscopy findings on each patient. Two blinded experts, unaffiliated with the clinical care of the study's subjects, reviewed the in-office arthroscopic images and MRI images using the surgical diagnostic arthroscopy images as the "control" group comparison. Patients were consecutive, and no patients were excluded from the study.

RESULTS

In this study, the accuracy, sensitivity, and specificity of in-office arthroscopy was equivalent to surgical diagnostic arthroscopy and more accurate than MRI. When comparing in-office arthroscopy with surgical diagnostic arthroscopy, all kappa statistics were between 0.766 and 0.902. For MRI compared with surgical diagnostic arthroscopy, kappa values ranged from a low of 0.130 (considered "slight" agreement) to a high of 0.535 (considered "moderate" agreement). The comparison of MRI to in-office arthroscopy showed very similar results as the comparison of MRI with surgical diagnostic arthroscopy, ranging from a low kappa of 0.112 (slight agreement) to a high of 0.546 (moderate agreement). There were no patient-related or device-related complications related to the use of in-office arthroscopy.

CONCLUSIONS

Needle-based diagnostic imaging that can be used in the office setting is statistically equivalent to surgical diagnostic arthroscopy with regard to the diagnosis of intra-articular, nonligamentous knee joint pathology. In-office diagnostic imaging can provide a more detailed and accurate diagnostic assessment of intra-articular knee pathology than MRI. Based on the study results, in-office diagnostic imaging provides a safe, accurate, real-time, minimally invasive diagnostic modality to evaluate intra-articular pathology without the need for surgical diagnostic arthroscopy or high-cost imaging.

LEVEL OF EVIDENCE

Level II, comparative prospective trial.

Bilateral Multiligamentous Knee Injuries: A Case Report and Technique Review

Bilateral knee dislocations are rare musculoskeletal injuries. We report a case of a patient who sustained traumatic bilateral knee dislocations resulting in multiligamentous injuries to both knees. The patient subsequently underwent acute ligamentous reconstructions of both knees performed at 2 weeks and 3 weeks after the initial injury. One year after these procedures, the patient has achieved excellent functional outcomes and has returned to recreational sports.

Grade III Distal Medial Collateral Ligament Tear Missed by Magnetic Resonance Imaging: A Report of Two Cases

Medial collateral ligament (MCL) injuries are the most common knee ligament injuries. Magnetic resonance imaging (MRI) is the investigation of choice for detecting such injuries. We report two cases of acute grade 3 MCL tears in young adults in which the injury was suspected clinically and was later confirmed by surgical exploration. However, the MRI failed to pick up the exact nature of injury. This report signifies the importance of an appropriate clinical examination for MCL injuries and stresses that decision-making for treatment should be based on the clinical examination rather than the MRI.

Varus-valgus instability in the anterior cruciate ligament-deficient knee: effect of posterior tibial load

Background

Anterior cruciate ligament (ACL) injury is often accompanied with medial collateral ligament (MCL) injury. Assessment of varus-valgus (V-V) instability in the ACL-deficient knee is crucial for the management of the concomitant ACL-collateral ligaments injury. We evaluated the V-V laxity and investigated the effect of additional posterior tibial load on the laxity in the ACL-deficient knee. Our hypothesis was that the V-V laxity in the ACL-deficient knee was greater than that in the intact knee and attenuated by additional posterior tibial load.

Methods

Eight fresh-frozen porcine knees were used, and a 6°-of-freedom (DOF) robotic system was utilized. A 5 Nm of V-V torque was applied to the intact knee, the ACL-deficient knee, and the ACL-deficient knee with 30 N of constant posterior tibial load, at 30° and 60° of flexion. Then, the 3D path in the intact knee was reproduced on the ACL-deficient knee. The total V-V angle under 5 Nm of V-V torque was assessed and compared among the three statuses. The in situ forces of the ACL under 5 Nm of varus and valgus torques, respectively, were also calculated.

Results

The total V-V angle in the ACL-deficient knee under 5 Nm of V-V torque was significantly greater than that in the intact knee, whereas the angle in the ACL-deficient knee with 30 N of posterior tibial load was significantly smaller than that in the ACL-deficient knee and approached that in the intact knee, at both 30° and 60° of flexion. The in situ force of the ACL was approximately 30 N at 30° and 16 N at 60° of flexion under 5 Nm of both varus and valgus torques.

Conclusions

The V-V laxity in the isolated ACL-deficient knee was greater than that in the intact knee. The increased laxity was attenuated and approached that in the intact knee by adding posterior tibial load. Application of posterior tibial load is necessary for accurate assessment of V-V instability in the ACL-deficient knee. Clinically, the V-V laxity in the combined ACL-MCL or ACL-LCL injured knee may be overestimated without posterior tibial load.

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.

Where does magnetic resonance imaging stand in the diagnosis of knee injuries?

BACKGROUND

The aim of this study was to determine the diagnostic value of magnetic resonance imaging (MRI) in the diagnosis of knee injuries.

MATERIALS AND METHODS

Ninety-eight consecutive patients were enrolled in the study. In all patients, MRI and arthroscopy were performed and the results were compared.

RESULTS

MRI was most sensitive in the detection of medial meniscus injuries, and the highest specificity and negative predictive value (NPV) were found in the detection of posterior cruciate ligament injuries.

CONCLUSION

MRI is a valuable tool, and according to its high NPV, normal MRI can prevent unnecessary arthroscopic interventions.

Bone bruises in anterior cruciate ligament injured knee and long-term outcomes. A review of the evidence

Background

Bone bruises are frequently associated with anterior cruciate ligament (ACL) tears as a result of trauma or direct shear stress of the bone.

Purpose

To review the evidence regarding the characteristics of the bone bruise associated with ACL tears, its relevance on clinical outcomes, and its progression over time. In particular, the long-term effects of the bone bruise on the knee osteochondral architecture and joint function were evaluated.

Study design

Review; level of evidence: 4.

Methods

An electronic search was performed on PubMed. Combinations of keywords included: “bone bruise AND knee”; “bone bruise AND anterior cruciate ligament”; “bone bruise AND osteo-chondral defects”. Any level of evidence studies concerning bone bruises in patients with partial or complete ACL tears were retrieved.

Results

A total of 25 studies were included; three of them investigated biomechanical parameters, seven were concerned with clinical outcomes, and 15 were radiological studies. Evaluation of the bone bruise is best performed using a fat-saturated T2-weighted fast spin echo exam or a short tau inversion recovery sequence where fat saturation is challenging. The location of the injury has been demonstrated to be more frequent in the lateral compartment of the joint (lateral femoral condyle and lateral tibial plateau). It is associated with ACL tears in approximately 70% of cases, often with collateral ligament or meniscal tears. Mid- and long-term outcomes demonstrated a complete healing of the marrow lesions at magnetic resonance imaging, but chondral defects detected with T1ρ sequences are still present 1 year after the ACL injury. Functional examination of the knee, through clinical International Knee Documentation Committee scores, did not show any correlation with the bone bruise.

Conclusion

Although bone bruise presence yields to higher pain levels, no correlation with functional outcomes was reported. Most studies have a short-term follow-up (<2 years) compared to the length of time it takes to develop post-traumatic osteoarthritis, so it still remains unclear whether the initial joint injury and bone bruise have a direct relationship to long-term function.

Clinical orthopedic examination findings in the lower extremity: correlation with imaging studies and diagnostic efficacy

The lower-extremity anatomy is complex and normal function is dependent on intact osteochondral, musculotendinous, and ligamentous structures. Injury may result in pain and functional limitation. Specific clinical tests are used to help isolate and define the pathoanatomy; however, their terminology may be confusing to the radiologist and the diagnostic value of these tests may not be well understood. This article presents an algorithmic approach to evaluation of the hip, knee, and ankle to improve the radiologist's understanding of lower-extremity physical examination. Knowledge of test terminology, clinical utility, and diagnostic accuracy will improve clinical and radiologic correlation. The article reviews the common clinical tests used to evaluate the lower extremity and provides an algorithm to establish a clinical examination road map and rapidly review the clinical utility and study hierarchy of a particular test. The sensitivity and specificity of the clinical tests and magnetic resonance (MR) imaging are reviewed because these parameters vary, and an understanding of the diagnostic utility of both the clinical and imaging tests is important in accurately formulating a definitive diagnosis. The structured algorithmic approach to lower-extremity examination described here, knowledge of test jargon, and familiarity with the diagnostic accuracy of the clinical and MR imaging examinations may help the radiologist focus image search patterns and provide detailed and clinically relevant reports. Online supplemental material is available for this article.

Prevalence and location of bone bruises associated with anterior cruciate ligament injury and implications for mechanism of injury: a systematic review

BACKGROUND

Bone bruising is commonly observed on magnetic resonance imaging (MRI) after non-contact anterior cruciate ligament (ACL) injury.

OBJECTIVES

The primary objective of this study was to determine if the location and prevalence of tibial and femoral bone bruises after ACL injury can be explained by specific injury mechanism(s). The secondary objective was to determine whether the bone-bruise literature supports sex-specific injury mechanism(s). We hypothesized that most studies would report bone bruising in the lateral femoral condyle (LFC) and on the posterior lateral tibial plateau (LTP).

METHODS

MEDLINE, PubMed, and SCOPUS were searched for studies that reported bone bruise prevalence and location in ACL-injured subjects. Sex differences in bone-bruise patterns were assessed. Time from injury to imaging was assessed to account for confounding effects on bone-bruise size and location.

RESULTS

Thirty-eight studies met the inclusion/exclusion criteria. Anterior-posterior location of bone bruises within the tibiofemoral compartment was assessed in 11 studies. Only five of these studies reported bone-bruise locations on both the tibia and the femur. The most common bone-bruise combination in all five studies was on the LFC and the posterior LTP. Sex differences were only assessed in three studies, and only one reported significantly greater prevalence of LTP bruising in females.

CONCLUSION

Bone-bruise patterns in the current literature support a valgus-driven ACL injury mechanism; however, more studies should report the specific locations of tibial and femoral bone bruises. There is insufficient evidence in the literature to determine whether there are sex-specific bone-bruise patterns in ACL-injured subjects.

The prevalence of knee injuries ipsilateral to tibial shaft fractures and their impact on clinical outcome

OBJECTIVE

The purpose of this prospective study was to examine the prevalence of occult knee injuries in patients with ipsilateral tibial shaft fractures and determine their impact on clinical outcome.

MATERIALS AND METHODS

Preoperative knee MRI examination was performed in 41 patients (42 knees) with isolated tibial shaft fractures. Menisci, cruciate ligaments, collateral ligaments, extensor mechanism, osteochondral lesions, bone contusions and knee effusion were evaluated. All patients were treated with reamed and locked intra-medullary tibial nailing without an additional surgical procedure for knee injuries. All patients were followed to at least fracture union and were evaluated with knee examination and Lysholm knee score.

RESULTS

Of the 42 knees, 41 (97.6 %) showed at least one defined injury around the knee. There was only one patient who had totally normal knee MRI findings. One or more ligamentous injuries of the knee were identified in 35 (83.3 %) of the knees. Five patents (11.9 %) had medial meniscal tear in posterior horn. Extensor mechanism injuries were seen in two patients. Mild to marked joint effusion was observed in 35 (81 %) knees. Twenty-two knees demonstrated bone bruise; femoral condyle (n = 7), tibial plateau (n = 12), patella (n = 2) and fibular head (n = 1). No patients had osteochondral lesion. Patients were followed with a mean of 13.2 ± 3.6 (range 8-22) months. Clinical knee examination revealed Grade II (+) anterior drawer test in two patients. The mean Lysholm knee score was 99.1 ± 2.14 (range 91-100) at the final follow-up.

CONCLUSIONS

Ipsilateral intra-articular, extra-articular or combined knee injuries may occur at the time of injury with tibial shaft fractures. However, most of these injuries are not clinically relevant and heal without any sequel or remain asymptomatic late after fracture union. Routine use of preoperative knee MRI examination in patients with tibial shaft fractures is not necessary.

Early magnetic resonance imaging in acute knee injury: a cost analysis

PURPOSE

Acute knee injury is common, and MRI is often only used when non-operative management fails because of limited availability. We investigated whether early MRI in acute knee injury is more clinically and cost-effective compared to conventional physiotherapy and reassessment.

METHODS

All patients with acute indirect soft tissue knee injury referred to fracture clinic were approached. Recruited patients were randomised to either the MRI group: early MRI within 2 weeks or the control group: conventional management with physiotherapy. Patients were assessed in clinic initially, at 2 weeks and 3 months post-injury. Management costs were calculated for all patients until surgical treatment or discharge.

RESULTS

Forty-six patients were recruited: 23 in the MRI and 23 in the control group. Male sex and mean age were similar in the two groups. The total management cost of the MRI group was £16,127 and control group was £16,170, with a similar mean cost per patient (NS). The MRI group had less mean physiotherapy (2.5 ± 1.9 vs. 5.1 ± 3.5, p < 0.01) and outpatient appointments (NS). Median time to surgery and time off work was less in the MRI group (NS). The MRI group had less pain (p < 0.05), less activity limitation (p = 0.04) and better satisfaction (p = 0.04).

CONCLUSIONS

Early MRI in acute knee injury facilitates faster diagnosis and management of internal derangement at a cost comparable to conventional treatment. Moreover, patients had significantly less time off work with improved pain, activity limitation and satisfaction scores.

LEVEL OF EVIDENCE

II.