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

Diagnosing popliteofibular ligament injuries in anterior cruciate ligament-injured knees: A prospective magnetic resonance imaging study investigating the inter- and intraobserver reliability of identification of the popliteofibular ligament

Purpose

The aim of our study was to investigate the intra- and interobserver reliability for the identification of the popliteofibular ligament (PFL) in magnetic resonance imaging (MRI) scans in patients with an anterior cruciate ligament (ACL) injury and ascertain the prevalence of PFL tears in ACL-injured knees without clinically high-grade posterolateral corner injury.

Methods

MRI readings were performed retrospectively by two surgeons on 84 patients who underwent ACL reconstruction in our department. The presence of the PFL on both sagittal and coronal images as well as the presence of PFL tears was noted. Readings were repeated 6 weeks later for one observer. The κ value was calculated to determine the intra- and interobserver reliability for identification of the PFL and the prevalence of PFL tears was ascertained.

Results

The PFL was visualized in 90.5%-91.7% of MRI scans. The intra- and interobserver reliability of visualizing the PFL on MRI had an κ value of 0.63 and 0.66 (substantially reliable), respectively. The intraobserver reliability for identification of PFL tears had an κ value of 0.26 (fair reliability). We found a 4.8% prevalence of PFL tears in ACL-injured knees.

Conclusions

There is substantially reliable intra- and interobserver reliability for the identification of the PFL on MRI scans but only fair reliability for the identification of PFL tears. A 4.8% prevalence of PFL tears in ACL-injured knees without clinically confirmed high-grade posterolateral corner injury can be observed in our series.

Level of Evidence

Level IV.

Is conventional magnetic resonance imaging superior to radiography in the functional integrity evaluation of anterior cruciate ligament in patients with knee osteoarthritis?

BACKGROUND

The functional integrity of the anterior cruciate ligament (ACL) influences surgical decision-making in patients with knee osteoarthritis (KOA). This study aimed to compare the diagnostic value of radiography and magnetic resonance imaging (MRI) in determining the functional status of ACL.

METHODS

We analyzed 306 knees retrospectively using preoperative hip-to-ankle anteroposterior standing (APS) radiographs, anteroposterior (AP) and lateral knee radiographs, AP valgus stress (VS) force radiographs, and standard orthogonal MRI. Based on the intraoperative visualization, the knees were grouped into ACL functionally-intact and ACL functionally-deficient (ACLD) groups. The diagnostic validity and reliability were calculated based on the radiograph parameters such as hip-knee-ankle angle (HKA), medial proximal tibial angle (MPTA), lateral distal femoral angle (LDFA), posterior tibial slope (PTS), sagittal tibiofemoral subluxation (STFS), coronal tibiofemoral subluxation (CTFS), joint line convergence angle (JLCA), the maximum wear point of the proximal tibia plateau (MWPPT%), and MRI parameters including ACL grades and MWPPT%.

RESULTS

HKA, MPTA, PTS, STFS, JLCA, and CTFS on APS and AP radiographs, and MWPPT% on radiographs and MRI showed a significant diagnostic value (P < 0.05). There were no statistically significant differences in the single parameters from radiographs and MRI. After constructing the logistic regression models, MRI showed higher sensitivity, specificity, and accuracy, reaching 96.8%, 79.9%, and 83.3%, respectively (P < 0.001).

CONCLUSIONS

In patients with KOA, the diagnostic value of single radiographic or MRI parameter in assessing the functional integrity of the ACL are equivalent. However, by constructing predictive models, MRI could significantly improve diagnostic validity compared with radiography.

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 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.

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.

Incidence of Associated Lesions of Multiligament Knee Injuries: A Systematic Review and Meta-analysis

Background:

The incidence of concomitant injuries, including meniscal and cartilage injuries, has not been adequately reported in previous studies on multiligament knee injury (MLKI) because their primary focal points have been the degree of ligament injury, treatment strategy, involvement of other soft tissues, and neurovascular injury.

Purpose:

To analyze the incidence of associated lesions in MLKIs, including medial and lateral meniscal injuries, cartilage lesions, and complications.

Study Design:

Systemic review; Level of evidence, 4.

Methods:

The PubMed, Embase, Cochrane Library, CINAHL, and Scopus databases were searched between inception and April 30, 2020. Studies were included if they reported the incidence rates of medial and/or lateral meniscal tears and cartilage injuries in cases of MLKIs. For the meta-analysis, data were extracted on clinical outcomes measured according to the number of medial and/or lateral meniscal tears, cartilage injuries, and complications.

Results:

A total of 45 studies were included in the MLKI analysis (3391 patients). The pooled rate of medial meniscal tears was 30.4% (95% CI, 24.1%-37.1%; P < .0001; I² = 85.8%). The pooled rate of lateral meniscal tears was 27.5% (95% CI, 20.3%-35.3%; P < .0001; I² = 89.6%). The pooled rate of cartilage injuries was 27.5% (95% CI, 22.1%-33.3%; P < .0001; I² = 86.8%). The pooled rates of peroneal nerve injuries, vascular injuries, and arthrofibrosis were 19.2% (95% CI, 14.2%-24.7%; P < .001; I² = 81.3%), 18.4% (95% CI, 13.2%-24.3%; P < .0001; I² = 81.0%), and 11.2% (95% CI, 8.1%-14.7%; P = .0018; I² = 54.0%), respectively.

Conclusion:

The pooled rates of meniscal tears and cartilage injuries concomitant with MLKIs were high, ranging from 27% to 30%, and the pooled rates of peroneal nerve injury, vascular injury, and arthrofibrosis were considerable, ranging from 11% to 19%. The influence of these associated lesions on clinical results should be evaluated in future clinical studies.

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.

Accuracy of MRI Diagnosis of Meniscal Tears of the Knee: A Meta-Analysis and Systematic Review

This study aimed to evaluate the overall diagnostic value of magnetic resonance imaging (MRI) in patients with suspected meniscal tears. PubMed, Cochrane, Embase database updated to November 2017 were searched by the index words to identify qualified studies, including prospective cohort studies and cross-sectional studies. Literature was also identified by tracking using reference lists. Heterogeneity of the included studies was reviewed to select proper effects model for pooled weighted sensitivity, specificity, and diagnostic odds ratio (DOR). Summary receiver operating characteristic (SROC) analyses were performed for meniscal tears. A total of 17 studies were involved in this meta-analysis to explore the diagnostic accuracy of MRI for meniscal tears. The global sensitivity and specificity of MRI of meniscal tears were 92.0% (95% confidence interval [CI]: 88.0-95.0%) and 90.0% (95% CI: 85.0-95.0%) in medial meniscal tears, and 80.0% (95% CI: 66.0-89.0%) and 95.0% (95% CI: 91.0-97.0%) in lateral meniscal tears, respectively. Moreover, the global positive and negative likelihood ratio of MRI of meniscal tears were 10.33 (95% CI: 6.04-17.67) and 0.09 (95% CI: 0.05-0.14) in medial meniscal tears; 16.48 (95% CI: 8.81-30.83) and 0.21 (95% CI: 0.12-0.37) in lateral meniscal tears, respectively. The global DOR was 81.69 (95% CI: 37.94-175.91) in medial meniscal tears and 56.59 (95% CI: 22.51-142.28) in lateral meniscal tears. The results of area under the SROC indicated high accuracy in medial meniscal tears (area under the curve [AUC] = 0.97, 95% CI: 0.95-0.98) and lateral meniscal tears (AUC = 0.96, 95% CI: 0.94-0.97). This review presents a systematic review and meta-analysis to evaluate the diagnostic accuracy of MRI of meniscal tears. Moderate-to-strong evidence suggests that MRI appears to be associated with higher diagnostic accuracy for detecting medial and lateral meniscal tears.