Faculty Bibliography

» Universal safety guidelines for the use of a knee-spanning external fixator in magnetic resonance imaging (MRI) are unlikely to be established considering the high variability in device construct configurations.» Per the US Food and Drug Administration, manufacturers are to provide parameters for safe MRI scanning for "MR Conditional" devices; however, such labeling may be limited in detail. Physicians should reference manufacturer labels as a starting point while making an educated clinical decision.» Scanning of a knee-spanning external fixator inside the MR bore has been safely demonstrated in previous studies, although with small sample sizes.» When considering MRI in a patient treated with a knee-spanning external fixator, physicians should use all available resources and coordinate with their medical team to make a clinically reasonable decision contrasting patient benefit vs. potential harm.

BACKGROUND:Detection of rotator cuff tears, a common cause of shoulder disability, can be time-consuming and subject to reader variability. Deep learning (DL) has the potential to increase radiologist accuracy and consistency. PURPOSE:The aim of this study was to develop a prototype DL model for detection and classification of rotator cuff tears on shoulder magnetic resonance imaging into no tear, partial-thickness tear, or full-thickness tear. MATERIALS AND METHODS:This Health Insurance Portability and Accountability Act-compliant, institutional review board-approved study included a total of 11,925 noncontrast shoulder magnetic resonance imaging scans from 2 institutions, with 11,405 for development and 520 dedicated for final testing. A DL ensemble algorithm was developed that used 4 series as input from each examination: fluid-sensitive sequences in 3 planes and a sagittal oblique T1-weighted sequence. Radiology reports served as ground truth for training with categories of no tear, partial tear, or full-thickness tear. A multireader study was conducted for the test set ground truth, which was determined by the majority vote of 3 readers per case. The ensemble comprised 4 parallel 3D ResNet50 convolutional neural network architectures trained via transfer learning and then adapted to the targeted domain. The final tear-type prediction was determined as the class with the highest probability, after averaging the class probabilities of the 4 individual models. RESULTS:The AUC overall for supraspinatus, infraspinatus, and subscapularis tendon tears was 0.93, 0.89, and 0.90, respectively. The model performed best for full-thickness supraspinatus, infraspinatus, and subscapularis tears with AUCs of 0.98, 0.99, and 0.95, respectively. Multisequence input demonstrated higher AUCs than single-sequence input for infraspinatus and subscapularis tendon tears, whereas coronal oblique fluid-sensitive and multisequence input showed similar AUCs for supraspinatus tendon tears. Model accuracy for tear types and overall accuracy were similar to that of the clinical readers. CONCLUSIONS:Deep learning diagnosis of rotator cuff tears is feasible with excellent diagnostic performance, particularly for full-thickness tears, with model accuracy similar to subspecialty-trained musculoskeletal radiologists.

Objective: Genicular artery embolization (GAE) is a novel, minimally invasive procedure for treatment of knee osteoarthritis (OA). This meta-analysis investigated the safety and effectiveness of this procedure. Design: Outcomes of this systematic review with meta-analysis were technical success, knee pain visual analog scale (VAS; 0"“100 scale), WOMAC Total Score (0"“100 scale), retreatment rate, and adverse events. Continuous outcomes were calculated as the weighted mean difference (WMD) versus baseline. Minimal clinically important difference (MCID) and substantial clinical benefit (SCB) rates were estimated in Monte Carlo simulations. Rates of total knee replacement and repeat GAE were calculated using life-table methods. Results: In 10 groups (9 studies; 270 patients; 339 knees), GAE technical success was 99.7%. Over 12 months, the WMD ranged from −34 to −39 at each follow-up for VAS score and −28 to −34 for WOMAC Total score (all p "‹< "‹0.001). At 12 months, 78% met the MCID for VAS score; 92% met the MCID for WOMAC Total score, and 78% met the SCB for WOMAC Total score. Higher baseline knee pain severity was associated with greater improvements in knee pain. Over 2 years, 5.2% of patients underwent total knee replacement and 8.3% received repeat GAE. Adverse events were minor, with transient skin discoloration as the most common (11.6%). Conclusions: Limited evidence suggests that GAE is a safe procedure that confers improvement in knee OA symptoms at established MCID thresholds. Patients with greater knee pain severity may be more responsive to GAE.

Background MRI is a powerful diagnostic tool with a long acquisition time. Recently, deep learning (DL) methods have provided accelerated high-quality image reconstructions from undersampled data, but it is unclear if DL image reconstruction can be reliably translated to everyday clinical practice. Purpose To determine the diagnostic equivalence of prospectively accelerated DL-reconstructed knee MRI compared with conventional accelerated MRI for evaluating internal derangement of the knee in a clinical setting. Materials and Methods A DL reconstruction model was trained with images from 298 clinical 3-T knee examinations. In a prospective analysis, patients clinically referred for knee MRI underwent a conventional accelerated knee MRI protocol at 3 T followed by an accelerated DL protocol between January 2020 and February 2021. The equivalence of the DL reconstruction of the images relative to the conventional images for the detection of an abnormality was assessed in terms of interchangeability. Each examination was reviewed by six musculoskeletal radiologists. Analyses pertaining to the detection of meniscal or ligament tears and bone marrow or cartilage abnormalities were based on four-point ordinal scores for the likelihood of an abnormality. Additionally, the protocols were compared with use of four-point ordinal scores for each aspect of image quality: overall image quality, presence of artifacts, sharpness, and signal-to-noise ratio. Results A total of 170 participants (mean age ± SD, 45 years ± 16; 76 men) were evaluated. The DL-reconstructed images were determined to be of diagnostic equivalence with the conventional images for detection of abnormalities. The overall image quality score, averaged over six readers, was significantly better (P < .001) for the DL than for the conventional images. Conclusion In a clinical setting, deep learning reconstruction enabled a nearly twofold reduction in scan time for a knee MRI and was diagnostically equivalent with the conventional protocol. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Roemer in this issue.

BACKGROUND:Magnetic resonance imaging (MRI) is an integral component of the treatment algorithm for proximal hamstring avulsion injuries. OBJECTIVE:The purpose of this study was to survey orthopedic surgeons and musculoskeletal radiologists on the reporting and analysis of proximal hamstring avulsions on MRI. METHODS:Two online surveys were developed to evaluate musculoskeletal radiologists' and orthopedic surgeons' perceptions of MRI-reporting for proximal hamstring avulsion injuries. Each survey was designed to provide information on physicians' best practices with respect to four primary questions (1) ischial tuberosity landmark determination (2) difficulties associated with measuring tendon retraction, (3) important ancillary findings, and (4) perceived clinical impact of measured retraction. Descriptive statistics were calculated for all categorical variables, which were reported as frequencies with percentages. Chi-squared test was utilized to compare rates of responses between surgeons and radiologists. Statistically significant differences were analyzed with post-hoc Fisher's exact tests; p < 0.05 considered statistically significant. RESULTS:218-Musculoskeletal radiologists and 33-orthopedic surgeons responded to their respective surveys. There were statistically significant differences with responses to two of the questions asked in both surveys; (1) in cases of complete hamstring avulsion (avulsion of both the semimembranosus and conjoint tendon), which arrow represents the tendon gap measurement used for planning surgery? p = 0.028; (2) in cases of avulsion of only the conjoint tendon, which arrow represents the tendon gap measurement used for planning surgery? p = 0.013. Post-hoc testing demonstrated that for either partial or complete hamstring avulsions, more surgeons use the conjoint tendon origin to measure tendon retraction than radiologists (p < 0.05 for both). Significantly more radiologists use the semimembranosus origin to measure hamstring retraction for partial or complete hamstring tears (p < 0.05 for both). However, for each of these questions, both radiologists and surgeons most frequently stated that the conjoint tendon landmark should be used for surgical planning. CONCLUSION/CONCLUSIONS:Musculoskeletal radiologists and orthopedists frequently utilize the conjoint tendon origin as an anatomic landmark for measuring complete and partial proximal hamstring avulsion injuries; though, orthopedists are more likely to utilize this landmark. Additionally, the broad surface area of the ischial tuberosity may lead to variability in measurement. CLINICAL IMPACT/CONCLUSIONS:Standard landmarks at the ischial tuberosity and/or detailed descriptions of tendon retractions would improve communication between radiologists and surgeons for proximal hamstring avulsions.

PURPOSE/OBJECTIVE:Multi-ligamentous knee injuries (MLKIs) are high-energy injuries that may infrequently present with concomitant patellar tendon rupture. There is limited information in the literature regarding these rare presentations, with even less information regarding clinical outcomes. Using propensity-score matching, the purpose of this study was to compare the outcomes of MLKIs with and without patellar tendon ruptures and to investigate the overall predictors of these outcomes. METHODS:Twelve patients who underwent surgical repair for combined MLKI and patellar tendon rupture from 2011 to 2020 with minimum 1-year follow-up data were identified from two separate institutions. Patients were propensity-score matched with a 1:1 ratio with controls based on age, body mass index (BMI), gender, and time from surgery. Patient-reported outcomes included International Knee Documentation Committee (IKDC) Subjective Knee Form, Lysholm and Tegner scores. RESULTS:Twelve MLKIs with concomitant patellar tendon injuries were identified out of a multicenter cohort of 237 (5%) patients sustaining MLKI and were case matched 1:1 with 12 MLKIs without extensor mechanism injuries. The average follow-up was 5.5 ± 2.6 years. There were no differences in Schenck Classification injury patterns. There were significant differences found across IKDC (Patellar Tendon mean: 53.1 ± 24.3, MLKI mean 79.3 ± 19.6, P < 0.001) and Lysholm scores (Patellar Tendon mean: 63.6 ± 22.3, MLKI mean 86.3 ± 10.7, P < 0.001) between the two, illustrating poorer outcomes for patients with concomitant patellar tendon ruptures. CONCLUSION/CONCLUSIONS:In the setting of MLKI, patients who have a concomitant patellar tendon rupture have worse functional outcomes compared to those without. This information will be important for patient counseling and might be considered to be added to Schenck classification, reflecting its prognostic value. LEVEL OF EVIDENCE/METHODS:Level IV.

INTRODUCTION/BACKGROUND:Peroneal nerve injuries are rare injuries and usually associated with multiligamentous knee injuries (MLKIs) involving one or both cruciate ligaments. The purpose of our study was to perform a multicenter retrospective cohort analysis to examine the rates of peroneal nerve injuries and to see whether a peroneal nerve injury was suggestive of a particular injury pattern. METHODS:A retrospective chart review was conducted in patients who were diagnosed with MLKI at two level I trauma centers from January 2001 to March 2021. MLKIs were defined as complete injuries to two or more knee ligaments that required surgical reconstruction or repair. Peroneal nerve injury was clinically diagnosed in these patients by the attending orthopaedic surgeon. Radiographs, advanced imaging, and surgical characteristics were obtained through a chart review. RESULTS:Overall, 221 patients were included in this study. The mean age was 35.9 years, and 72.9% of the population was male. Overall, the incidence of clinical peroneal nerve injury was 19.5% (43 patients). One hundred percent of the patients with peroneal nerve injury had a posterolateral corner injury. Among patients with peroneal nerve injury, 95.3% had a complete anterior cruciate ligament (ACL) rupture as compared with 4.7% of the patients who presented with an intact ACL. There was 4.4 times of greater relative risk of peroneal nerve injury in the MLKI with ACL tear group compared with the MLKI without an ACL tear group. No statistical difference was observed in age, sex, or body mass index between patients experiencing peroneal nerve injuries and those who did not. CONCLUSION/CONCLUSIONS:The rate of ACL involvement in patients presenting with a traumatic peroneal nerve palsy is exceptionally high, whereas the chance of having a spared ACL is exceptionally low. More than 90% of the patients presenting with a nerve palsy will have sustained, at the least, an ACL and posterolateral corner injury. LEVEL OF EVIDENCE/METHODS:IV, Case Series.

Background/UNASSIGNED:Peroneal nerve (PN) palsy is one of the most debilitating sequelae of multiligamentous knee injuries (MLKIs). There is limited research on recovery from complete PN palsy. Purpose/Hypothesis/UNASSIGNED:The purpose of this study was to characterize PN injuries and develop a predictive model of complete PN recovery after MLKI using machine learning. It was hypothesized that elevated body mass index (BMI) would be predictive of lower likelihood of recovery. Study Design/UNASSIGNED:Case-control study; Level of evidence, 3. Methods/UNASSIGNED:The authors conducted a retrospective review of patients seen at 2 urban hospital systems for treatment of MLKI with associated complete PN palsy, defined as the presence of complete foot drop with or without sensory deficits on physical examination. Recovery was defined as the complete resolution of foot drop. A random forest (RF) classifier algorithm was used to identify demographic, injury, treatment, and postoperative variables that were significant predictors of recovery from complete PN palsy. Validity of the RF model was assessed using overall accuracy, F1 score, and area under the receiver operating characteristic curve (AUC). Results/UNASSIGNED:Overall, 16 patients with MLKI with associated complete PN palsy were included in the cohort. Among them, 75% (12/16) had documented knee dislocation requiring reduction. Complete recovery occurred in 4 patients (25%). Nerve contusions on magnetic resonance imaging were more common among patients without PN recovery, but there were no other significant differences between recovery and nonrecovery groups. The RF model found that older age, increasing BMI, and male sex were predictive of worse likelihood of PN recovery. The model was found to have good validity, with a classification accuracy of 75%, F1 score of 0.86, and AUC of 0.64. Conclusion/UNASSIGNED:The RF model in this study found that increasing age, BMI, and male sex were predictive of decreased likelihood of nerve recovery. While further study of machine learning models with larger patient data sets is required to identify the most superior model, these findings present an opportunity for orthopaedic surgeons to better identify, counsel, and treat patients with MLKIs and concomitant complete PN palsy.

PURPOSE/OBJECTIVE:The purpose of this study was to evaluate the mid-term results of posterior medial meniscal root tear (PMMRT) repair through assessment of functional outcome scores and magnetic resonance imaging (MRI). METHODS:This was a single-center, retrospective study evaluating patients that had undergone a PMMRT. This was a follow-up to a previously published 2-year outcome study (all original patients were invited to participate). Clinical outcomes included pre- and postoperative International Knee Documentation Committee (IKDC) and Lysholm scores. Root healing, meniscal extrusion, and cartilage degeneration via International Cartilage Repair Society Scale (ICRS) grades were assessed on MRI by two musculoskeletal fellowship-trained radiologists. RESULTS:10 of the original study's 18 patients were able to participate. Mean age and BMI was 48.4 ± 12.0 years and 29.5 ± 4.5, respectively, with mean follow-up 65.5 ± 8.3 months (range 52.0-75.8) (60% female). The IKDC significantly increased from 43 ± 13 preoperatively to 75 ± 16 at 5-year follow-up (p < 0.001). There was no significant change in IKDC score between 2-year and 5-year follow-up [75 ± 16 vs 73 ± 20, (n.s)]. The Lysholm also significantly increased between preoperative and 5-year follow-up (49 ± 7 vs 84 ± 11, p < 0.001). There was no significant change between Lysholm score at 2-year and 5-year follow-up [84.0 ± 11 vs 82 ± 13, (n.s)]. Mean extrusion did not significantly change from the preoperative state to 5-year follow-up [4.80 mm ± 1.9 vs 5.0 mm ± 2.5, (n.s.)]. Extrusion also did not significantly change between 2-and 5-year follow-up [6.1 ± 3.2 mm vs 5.0 mm ± 2.5, (n.s.)]. No patients with > 3 mm of extrusion on preoperative MRI had < 3 mm of extrusion on postoperative MRI. Both medial femoral condyle and medial tibial plateau ICRS grades significantly increased from preoperative to 2-year follow-up (p = 0.038, p = 0.023, respectively). Medial femoral condyle and medial tibial plateau ICRS grades again significantly increased between 2-year and 5-year follow-up (p = 0.014, p = 0.034). CONCLUSION/CONCLUSIONS:Patients treated with the transtibial suture pullout technique with two locking cinch sutures had maintenance of clinical outcome improvements at 5-year follow-up. However, extrusion was widely prevalent, with worsening progression of femoral and tibial chondral disease. LEVEL OF EVIDENCE/METHODS:Level 4.

Purpose: To determine the safety and effectiveness of genicular artery embolization (GAE) in reducing knee pain in patients with mild to moderate knee osteoarthritis (OA), as measured by validated patient reported outcome measures, and to characterize pre/post-procedural trends in multiple OA-associated serum biomarkers
Material(s) and Method(s): In an ongoing, prospective, single-arm clinical trial, patients with mild to moderate (Kellgren-Lawrence grade 2-3) symptomatic knee OA, without prior surgery and who failed conservative therapy, were included. Pre-intervention imaging (plain radiographs and MRI), patient-reported outcome measures (KOOS, WOMAC, VAS), and serum biomarkers (IL-1Ra, CRP, Hyaluronan, COMP, VEGF, CCL2-MCP-1) were obtained. Each patient underwent transcatheter arterial embolization of one or more genicular arteries in the affected knee using 250-mum microspheres (Embozene, Varian). One- and three-month post-intervention patient-reported outcome measures and serum biomarkers were obtained. Baseline and follow-up outcomes were compared using paired Wilcoxon signed-rank tests.
Result(s): The first 7 patients (4 male, mean age 68 +/- 6y, mean BMI 30 +/- 2) recruited into this trial were included in this preliminary analysis. Technical success was 100%. There were no adverse events. By 3 months, VAS pain scores decreased from 56 to 21 (63% decrease); WOMAC pain scores decreased from 8 to 4 (50% decrease); and KOOS pain scores (for which higher scores indicate less pain) increased from 57 to 81 (42% increase), all P >0.05. Baseline and 3-month mean biomarker values were: IL-1Ra (471 +/- 276 vs 590 +/- 320 pg/mL), CRP (1.81 +/- 1.78 vs 3.24 +/- 4.25 mg/L), Hyaluronan (92 +/- 66 vs 166 +/- 102 ng/mL), COMP (942 +/- 336 vs 1057 +/- 462 ng/mL), VEGF (372 +/- 283 vs 303 +/- 101 pg/mL), and CCL2-MCP-1 (335 +/- 90 vs 323 +/- 69 pg/mL), all P >0.05.
Conclusion(s): Patient-reported pain scores demonstrated a trend in improvement 3 months after GAE at our interim analysis. There were no significant changes between baseline and 3-month follow-up in serum OA biomarkers in this small sample size. Full study analysis will further delineate trends in serum biomarkers after GAE.
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