Fellowship-trained Musculoskeletal Radiologists Research Articles

Management of Patellar and Trochlear Cartilage Lesions with Matrix-Induced Autologous Chondrocyte Implantation in Conjunction with Patellofemoral Realignment Procedures Improves Patient Reported Outcomes and Magnetic Resonance Image Appearance

ObjectivesThe aim of this study is to evaluate the relationship between the achievement of clinically significant improvement in patient-reported outcome measures (PROMs) and the postoperative magnetic resonance image (MRI) appearance of matrix-associated chondrocyte implantation (MACI), in conjunction with patellofemoral realignment procedures, for the treatment of grade IV chondral defects about the patellofemoral joint. MethodsA retrospective review of patients undergoing MACI for grade IV chondral defects of the patella or trochlea by a single sports medicine fellowship-trained surgeon from 2017-2020 was performed. Concomitant realignment procedures, including tibial tubercle osteotomy and medial patellofemoral ligament reconstruction, were also performed as needed. Patients with preoperative and minimum 1-year postoperative PROMs and postoperative knee MRI were included. MRI were obtained at 6.3 [Interquartile range (IQR): 5.8, 7.5] months postoperatively. A fellowship-trained musculoskeletal radiologist assigned a Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score (range: 0-100, with 100 equating to complete graft healing) to each MRI. Achievement of the minimal clinically important difference (MCID) for International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Score–Quality of Life (KOOS-QoL), and Kujala scores were determined for each patient. Paired t-tests or Wilcoxon Rank-Sum tests were used to evaluate for an association between achievement of the MCID for each PROM and MOCART scores. The average follow-up time and time from surgery to PROMs were 2.7±1.5 years and 1.7±0.66 years, respectively. ResultsThirty patients were included. There was a significant improvement in all PROMs from pre- to postoperative (p<0.001). More than two thirds of patients achieved the MCID for each PROM. Patients who achieved the MCID for IKDC had significantly higher MOCART scores (66.5±16.2) compared to those who did not meet the MCID for IKDC (50.6±23.6, p=0.043). ConclusionMACI for the treatment of patellofemoral chondral injuries is associated with clinically significant improvement in PROMs at short-term follow up. Clinically significant improvements in IKDC scores are associated with a more mature MRI appearance of the ACI graft on postoperative MRI, as indicated by higher MOCART scores. Level of EvidenceIV – Case Series

Association of tibial slope alterations with anterior cruciate ligament (ACL) injury and mucoid degeneration.

To compare radiographic measurements of lateral tibial slope (LTS), medial TS (MTS), and coronal TS (CTS) in MRI-defined intact, injured, and mucoid-degenerated native ACL knees and determine inter-reader reliability. Patient records from 2years at tertiary care hospitals were reviewed for individuals aged 18-100 undergoing 3-Tesla knee MRI and radiographs. Two randomly selected cohorts, control, and pathologic ACLs on MRI with 86 patients each, were age, gender, and BMI-matched. A fellowship-trained musculoskeletal radiologist reevaluated curated images, characterizing ACL status. Two trained medical students independently collected clinical data and measured slopes on blinded radiographs. ICC, Cohen's kappa, and case-control matching were performed using SPSS statistical package, with ICC and ANOVA used for comparisons. Among 172 patients with 172 MRIs and radiographs, there were 86 controls and 86 ACL lesions. There were 108/172 (62.79%) males and 64/172 (37.21%) females. ICCs were 0.966 for MTS, 0.975 for LTS, and 0.978 for CTS. Mucoid degeneration patients had a higher BMI and were older than control (p < .05) or completely torn (p < .001) ACL patients. There was no difference in TS between normal and pathologic ACLs; however, LTS-MTS differences were larger with partial tears (2.5 ± 4.9) than normal ACLs by 4.5° (± 1.2, p < .001), complete tears by 4.5° (± 1.3, p < .001), and mucoid degeneration by 4.9° (± 1.5, p = .001). Various TS measurements are reliable. LTS-MTS differences are associated with different ACL lesions compared to normal ACLs.

Presence of Additional Pathology in Low-Grade Acromioclavicular Joint Injuries.

To determine if additional pathology is present in low-grade acromioclavicular (AC) joint injuries. Prospective case series. Patients were assessed by primary care sports medicine physicians at a single institution between 2019 and 2023. Patients aged 18 to 65 years diagnosed with a type I to III AC injury based on clinical and radiographic evaluation. Consenting patients underwent magnetic resonance imaging (MRI) evaluation within 21 days of injury. All injuries were treated nonoperatively. Additional pathologies identified on MRI were reported in a standardized fashion by fellowship-trained musculoskeletal radiologists. Twenty-nine patients (26 men/3 women) were consented with a mean (±SD) age of 28.6 ± 9.5 years. The mean time from injury to MRI was 8.1 ± 5.9 days. Twenty-three injuries were sport related, and 6 were accidental traumas. Based on MRI, injury type was reclassified in 16 of 29 patients, and 13 remained unchanged. Additional pathologies identified included 14 muscle injuries, 5 rotator cuff tears, 5 labral tears, 1 nondisplaced fracture, and 1 intra-articular body. MRI evidence suggests that most AC joint injuries are more severe than clinically diagnosed. Identifying additional pathology may alter diagnostic and treatment guidelines for type I to III AC joint injuries.

Medial meniscus extrusion is associated with meniscus tears in US and MRI: A case control study.

To study the medial meniscus extrusion (MME) in subjects with and without medial meniscal tears on magnetic resonance imaging (MRI), supine ultrasound (US), and weight-bearing US. Forty-seven cases (mean age 43.7 years) with medial meniscus tears and 53 healthy controls (mean age 36.6 years) were assessed. Two experienced sonographers performed the US evaluations, and a fellowship-trained musculoskeletal radiologist assessed the menisci on MRI. Independent and paired T-tests and ICC were used for statistical analyses. On supine US, the mean MME was 3.9 mm for the cases and 2.3 mm for the controls (p < 0.001). On weight-bearing US, the values were 4.2 and 2.8 mm (p < 0.001), and on MRI 3.0 and 2.0 mm (p < 0.001), respectively. The mean difference between supine and weight-bearing US extrusion was 0.38 mm for the cases and 0.49 mm for the controls (p = 0.291). Correlation between supine US and MRI MME measurements was good (ICC = 0.660, CIs [0.533-0.758]). MME can be assessed using US with good correlation to MRI. US-observed extrusion was significantly increased in supine and standing positions for medial meniscus tears. The mean difference between examination positions was reduced with medial meniscus tears although this result was statistically insignificant.

Gradient-Based Saliency Maps Are Not Trustworthy Visual Explanations of Automated AI Musculoskeletal Diagnoses.

Saliency maps are popularly used to "explain" decisions made by modern machine learning models, including deep convolutional neural networks (DCNNs). While the resulting heatmaps purportedly indicate important image features, their "trustworthiness," i.e., utility and robustness, has not been evaluated for musculoskeletal imaging. The purpose of this study was to systematically evaluate the trustworthiness of saliency maps used in disease diagnosis on upper extremity X-ray images. The underlying DCNNs were trained using the Stanford MURA dataset. We studied four trustworthiness criteria-(1) localization accuracy of abnormalities, (2) repeatability, (3) reproducibility, and (4) sensitivity to underlying DCNN weights-across six different gradient-based saliency methods (Grad-CAM (GCAM), gradient explanation (GRAD), integrated gradients (IG), Smoothgrad (SG), smooth IG (SIG), and XRAI). Ground-truth was defined by the consensus of three fellowship-trained musculoskeletal radiologists who each placed bounding boxes around abnormalities on a holdout saliency test set. Compared to radiologists, all saliency methods showed inferior localization (AUPRCs: 0.438 (SG)-0.590 (XRAI); average radiologist AUPRC: 0.816), repeatability (IoUs: 0.427 (SG)-0.551 (IG); average radiologist IOU: 0.613), and reproducibility (IoUs: 0.250 (SG)-0.502 (XRAI); average radiologist IOU: 0.613) on abnormalities such as fractures, orthopedic hardware insertions, and arthritis. Five methods (GCAM, GRAD, IG, SG, XRAI) passed the sensitivity test. Ultimately, no saliency method met all four trustworthiness criteria; therefore, we recommend caution and rigorous evaluation of saliency maps prior to their clinical use.

Artificial intelligence improves resident detection of pediatric and young adult upper extremity fractures.

We wished to evaluate if an open-source artificial intelligence (AI) algorithm ( https://www.childfx.com ) could improve performance of (1) subspecialized musculoskeletal radiologists, (2) radiology residents, and (3) pediatric residents in detecting pediatric and young adult upper extremity fractures. A set of evaluation radiographs drawn from throughout the upper extremity (elbow, hand/finger, humerus/shoulder/clavicle, wrist/forearm, and clavicle) from 240 unique patients at a single hospital was constructed (mean age 11.3years, range 0-22years, 37.9% female). Two fellowship-trained musculoskeletal radiologists, three radiology residents, and two pediatric residents were recruited as readers. Each reader interpreted each case initially without and then subsequently 3-4weeks later with AI assistance and recorded if/where fracture was present. Access to AI significantly improved area under the receiver operator curve (AUC) of radiology residents (0.768 [0.730-0.806] without AI to 0.876 [0.845-0.908] with AI, P < 0.001) and pediatric residents (0.706 [0.659-0.753] without AI to 0.844 [0.805-0.883] with AI, P < 0.001) in identifying fracture, respectively. There was no evidence of improvement for subspecialized musculoskeletal radiology attendings in identifying fracture (AUC 0.867 [0.832-0.902] to 0.890 [0.856-0.924], P = 0.093). There was no evidence of difference between overall resident AUC with AI and subspecialist AUC without AI (resident with AI 0.863, attending without AI AUC 0.867, P = 0.856). Overall physician radiograph interpretation time was significantly lower with AI (38.9s with AI vs. 52.1s without AI, P = 0.030). An openly accessible AI model significantly improved radiology and pediatric resident accuracy in detecting pediatric upper extremity fractures.

Diagnosing periprosthetic hip joint infection with new-generation 0.55 T MRI

PurposeTo assess the accuracy of 0.55 T MRI in diagnosing periprosthetic joint infection (PJI) in patients with symptomatic total hip arthroplasty (THA). Material and methods0.55 T MRI of patients with THA PJI (Group A) and noninfected THA (Group B), including aseptic loosening (Group C, subgroup of B) performed between May 2021 and July 2023 were analysed retrospectively.Two musculoskeletal fellowship-trained radiologists independently identified MRI bone and soft tissue changes including: marrow oedema, periosteal reaction, osteolysis, joint effusion, capsule oedema and thickening, fluid collections, muscle oedema, bursitis, inguinal adenopathy, and muscle tears. The diagnostic performance of MRI discriminators of PJI was evaluated using Fisher’s exact test (p < 0.05) and interrater reliability was determined. 61 MRI scans from 60 THA patients (34 female, median age 68, range 41–93 years) in Group A (n = 9; female 4; median age 69, range 56–82 years), B (n = 51; 30; 67.5, 41–93 years), and C (10; 6; 67; 41–82 years) were included. ResultsCapsule oedema (sensitivity 89 %, specificity 92 %,), intramuscular oedema (89 %, 82 %) and joint effusion (89 %, 73 %) were the best performing discriminators for PJI diagnosis (p ≤ 0.001), when viewed individually and had combined 70 % sensitivity and 100 % specificity for PJI diagnosis in parallel testing. For the differentiation between PJI and aseptic loosening, intramuscular oedema (89 %, 80 %) and capsule oedema (89 %, 80 %) were significant discriminators (p ≤ 0.001) with combined 64 % sensitivity and 96 % specificity for PJI. ConclusionsNew generation 0.55 T MRI may aid in the detection of PJI in symptomatic patients. Oedema of the joint capsule, adjacent muscles as well as joint effusion were indicative of the presence of PJI.

Metal artifact reduction sequence-MRI abnormalities in asymptomatic patients with dual-mobility hip prostheses.

Modular dual-mobility (DM) articulations are increasingly used during total hip arthroplasty (THA). However, concerns remain regarding the metal liner modularity. This study aims to correlate metal artifact reduction sequence (MARS)-MRI abnormalities with serum metal ion levels in patients with DM articulations. A total of 45 patients (50 hips) with a modular DM articulation were included with mean follow-up of 3.7 years (SD 1.2). Enrolled patients with an asymptomatic, primary THA and DM articulation with over two years' follow-up underwent MARS-MRI. Each patient had serum cobalt, chromium, and titanium levels drawn. Patient satisfaction, Oxford Hip Score, and Forgotten Joint Score-12 (FJS-12) were collected. Each MARS-MRI was independently reviewed by fellowship-trained musculoskeletal radiologists blinded to serum ion levels. Overall, two patients (4.4%) had abnormal periprosthetic fluid collections on MARS-MRI with cobalt levels > 3.0 μg/l. Four patients (8.9%) had MARS-MRI findings consistent with greater trochanteric bursitis, all with cobalt levels < 1.0 μg/l. A seventh patient had a periprosthetic fluid collection with normal ion levels. Of the 38 patients without MARS-MRI abnormalities, 37 (97.4%) had cobalt levels < 1.0 μg/l, while one (2.6%) had a cobalt level of 1.4 μg/l. One patient (2.2%) had a chromium level > 3.0 μg/l and a periprosthetic fluid collection. Of the 41 patients with titanium levels, five (12.2%) had titanium levels > 5.0 μg/l without associated MARS-MRI abnormalities. Periprosthetic fluid collections associated with elevated serum cobalt levels in patients with asymptomatic DM articulations occur infrequently (4.4%), but further assessment is necessary due to implant heterogeneity.

AI-Based Measurement of Lumbar Spinal Stenosis on MRI: External Evaluation of a Fully Automated Model.

The aim of this study was to clinically validate a fully automated AI model for magnetic resonance imaging (MRI)-based quantifications of lumbar spinal canal stenosis. This retrospective study included lumbar spine MRI of 100 consecutive clinical patients (56 ± 17 years; 43 females, 57 males) performed on clinical 1.5 (51 examinations) and 3 T MRI scanners (49 examinations) with heterogeneous clinical imaging protocols. The AI model performed segmentations of the thecal sac on axial T2-weighted sequences. Based on these segmentations, the anteroposterior (AP) and mediolateral (ML) distance, and the area of the thecal sac were measured in a fully automated manner. For comparison, 2 fellowship-trained musculoskeletal radiologists performed the same segmentations and measurements independently. Statistics included 1-sample t tests, the intraclass correlation coefficient (ICC), Bland-Altman plots, and Dice coefficients. A P value of <0.05 was considered statistically significant. The average measurements of the AI model, reader 1, and reader 2 were 194 ± 72 mm 2 , 181 ± 71 mm 2 , and 179 ± 70 mm 2 for thecal sac area, 13 ± 3.3 mm, 12.6 ± 3.3 mm, and 12.6 ± 3.2 mm for AP distance, and 19.5 ± 3.9 mm, 20 ± 4.3 mm, and 19.4 ± 4 mm for ML distance, respectively. Significant differences existed for all pairwise comparisons, besides reader 1 versus AI model for the ML distance and reader 1 versus reader 2 for the AP distance ( P = 0.1 and P = 0.21, respectively). The pairwise mean absolute errors among reader 1, reader 2, and the AI model ranged from 0.59 mm and 0.75 mm for the AP distance, from 1.16 mm to 1.37 mm for the ML distance, and from 7.9 mm 2 to 15.54 mm 2 for the thecal sac area. Pairwise ICCs among reader 1, reader 2, and the AI model ranged from 0.91 and 0.94 for the AP distance and from 0.86 to 0.9 for the ML distance without significant differences. For the thecal sac area, the pairwise ICC between both readers and the AI model of 0.97 each was slightly, but significantly lower than the ICC between reader 1 and reader 2 of 0.99. Similarly, the Dice coefficient and Hausdorff distance between both readers and the AI model were significantly lower than the values between reader 1 and reader 2, overall ranging from 0.93 to 0.95 for the Dice coefficients and 1.1 to 1.44 for the Hausdorff distances. The investigated AI model is reliable for assessing the AP and the ML thecal sac diameters with human level accuracies. The small differences for measurement and segmentation of the thecal sac area between the AI model and the radiologists are likely within a clinically acceptable range.

Correlation Between Traditional Anteroposterior Radiographic Measurements With Lateral Radiographic Measurements Following Triplanar Correction of Hallux Valgus and With Patient-Reported Outcomes From a Prospective Multicenter Trial

Hallux valgus (HV) is a common condition in which the first ray is deformed, leading to pain and altered joint mechanics. A variety of radiographic measurements are used to evaluate HV. Little is known about measurements used in the assessment of HV on lateral radiographs compared to anteroposterior (AP) radiographs. The primary aim of this study was to correlate lateral measurements with AP measurements pre and postoperatively. The secondary aim was to correlate lateral measurements with patient-reported outcome measures (PROMs) pre and postoperatively.One hundred eighty-three patients were initially enrolled in the study. Two fellowship-trained musculoskeletal radiologists independently performed all measurements. On AP radiographs, hallux valgus angle (HVA) and intermetatarsal angle (IMA) were measured. On lateral radiographs, sagittal IMA, Meary's angle, and sagittal first ray length were measured. Measurements were recorded at baseline and 6, 12, and 24 months postoperatively. Intraclass correlation coefficients (ICCs) were used for inter-reader analysis. ICCs were moderate to very strong among readers. There were significant but weak correlations between lateral measurements and AP measurements. For at least 1 timepoint, IMA correlated with sagittal IMA, sagittal first ray length, and Meary's angle. HVA only correlated with sagittal first ray length. These correlations were all weak in magnitude. There were a few significant but weak correlations between the measurements in the study and PROMs. This study showed that sagittal IMA, sagittal first ray length, and Meary's angle are not predictive of AP measurements or patient outcomes and are not useful in preoperative assessment of HV.

Is there a change in ischiofemoral space in lateral position in comparison to supine

Ischiofemoral impingement (IFI) is caused due to impingement of soft tissues between the ischium and the lesser trochanter of the femur, resulting in pain and discomfort. IFI can be caused due to anatomical abnormality, previous trauma and surgery. The quadratus femoris muscle is usually affected in these cases, which can become oedematous and show fatty atrophy. Management of IFI include analgesics, physiotherapy, image-guided intervention and surgery. This study aims to provide an overview of IFI, evaluate the ischiofemoral space in a cohort of ten patients, and suggest the safest position for image-guided interventions in patients with IFI. The ischiofemoral space and distance between the sciatic nerve and the medial part of the femoral neck were measured in supine and lateral positions on 10 consecutive patients by two fellowship-trained musculoskeletal radiologists on Computed Tomography (CT) axial sequence. There were 10 patients in the study (3 female and 7 males), with an average age of 29 years (11-70 years). A statistically significant increase in the ischiofemoral space and the distance between the sciatic nerve and the medial part of the femoral neck was found in the lateral position compared to the supine position. There was good intra- and inter-observer reliability, with a kappa value of 0.8. The increase in the ischiofemoral interval in the lateral position suggests that it is relatively safer to perform image-guided interventions and injections in the ischiofemoral interval in the lateral position with a potential reduction in the risk of incidental sciatic nerve injury.

Single-Plane 3-Dimensional Isotropic Spin-Echo Magnetic Resonance Imaging Reconstructions of Shoulder Exhibit Superior Correlation to Surgical Findings Than 2-Dimensional Dixon Multiplanar Magnetic Resonance Imaging.

The aim of the study is to evaluate concordance of multiplanar 2-dimensional magnetic resonance imaging (2D-MRI) versus 3D isotropic MRI for rotator cuff and labral tears with the reference standard of arthroscopic surgical findings. It was an institutional review board-approved retrospective single-center study of consecutive preoperative patients with isotropic 3D-MRI on 3-Tesla scanners, multiplanar 2D-MRI, and shoulder arthroscopy. Scapular plane-oriented contiguous multiplanar reconstructions of 3D-images were evaluated by 2 experienced fellowship-trained musculoskeletal radiologists. Variables included the following: labral tear presence and rotator-cuff tear Ellman grade, thickness, and width. Sensitivities (Sen) and specificities (Spe) were calculated for binary variables. Mean squared errors (MSE) were calculated for ordinal variables. Lower MSE indicated higher concordance. Seventy-two patients (43 female) with a mean age of 50.75 ± 9.76 years were evaluated. For infraspinatus-tear presence, 3D-MRI showed higher sensitivity (0.96) and specificity (0.68) than 2D-MRI (Sen = 0.85, Spe = 0.32) ( Psen = 0.005, Pspe = 0.002). For subscapularis-tear presence, 3D-MRI showed higher sensitivity (0.94) and specificity (0.73) compared with 2D-MRI (Sen = 0.83, Spe = 0.56) ( Psen = 0.02, Pspe = 0.04). For supraspinatus-tear presence, there was no significant difference between 3D-MRI (Sen =0.96, Spe = 0.67) compared with 2D-MRI (Sen = 0.98, Spe = 0.83) ( Psen = 0.43, Pspe = 0.63). For infraspinatus-tear thickness, 3D-MRI showed lower MSE (0.35) compared with 2D-MRI MSE (0.82) ( P = 0.01). For subscapularis-tear thickness, 3D-MRI had lower MSE (0.31) compared with 2D-MRI MSE (0.51) ( P = 0.007). However, no difference noted for supraspinatus-tear thickness when comparing 3D-MRI MSE (0.39) and 2D-MRI MSE (0.51) ( P = 0.49). For labral-tear presence, 3D-MRI had a lower MSE (0.20) compared with 2D-MRI MSE (0.57) ( P < 0.001). Three-dimensional MRI of the shoulder is time efficient with a shorter acquisition time and exhibits comparable with superior correlation to surgical findings than 2D-MRI for detection of labral tears and some rotator cuff tears. Three-dimensional MRI may be used in place of traditional 2D-MRI in detection of soft-tissue shoulder injury in centers equipped to do so.

Poster 300: A Novel Magnetic Resonance Imaging (MRI) Scoring System to Evaluate Patellofemoral Osteoarthritis

Objectives: Knee osteoarthritis (OA) is a common degenerative or post-traumatic condition, and may affect one or more compartments, including the medial and lateral tibiofemoral or patellofemoral articulations. Isolated patellofemoral osteoarthritis (PFOA) has been reported in 24% of women and 11% of men aged &gt; 55 years presenting for evaluation of knee pain. PFOA is a result of abnormal mechanical loading across the patellofemoral joint, often related to prior instability, trauma, malalignment or post- surgical changes. Treatment of PFOA typically includes a trial of conservative management, including physical therapy, injections and activity modification. Operative treatment involves joint preservation (i.e., cartilage restoration procedures, tibial tubercle osteotomy, or lateral lengthening) and joint replacement (patellofemoral arthroplasty) procedures. In contrast to the tibiofemoral compartments, the current literature lacks a reliable magnetic resonance imaging (MRI) scoring system to quantitatively evaluate patellofemoral cartilage degeneration. The present study aims to describe, apply and assess the inter-observer reliability of a novel MRI scoring system for assessment of the patellofemoral cartilage. Methods: We conducted a query of an institutional database to identify all patients who underwent patellofemoral arthroplasty by the senior surgeon (S.M.S.) between January 2012 and December 2021. Patients with poor quality or lacking preoperative knee MRI were excluded. MRI scans were performed on 1.5 or 3.0-Tesla magnets utilizing dedicated extremity coils and standardized clinical imaging protocols consistent with International Cartilage Regeneration and Joint Preservation Society (ICRS) guidelines for the assessment of articular cartilage. Preoperative MRI scans were reviewed and patellofemoral cartilage was scored by a fellowship-trained musculoskeletal radiologist and a fellowship- trained orthopedic knee surgeon using our novel MRI scoring system. The novel semi-quantitative MRI patellofemoral scoring system includes assessment of patellar and trochlear cartilage, bony architecture, patellofemoral alignment, and synovitis (Table 1). For statistical analysis, inter-observer agreement was assessed using Cohen-Kappa coefficient for categorical variables, and intraclass correlation coefficient (ICC) for the total score. The measurement agreement for reach variable and total score was interpreted according to the Landis and Koch criteria: 0 - 0.2, slight; 0.21 - 0.4, fair; 0.41 - 0.6, moderate; 0.61 - 0.80, substantial; 0.81 - 1.0, almost perfect. Results: A total of 72 patients were included in the final analysis. The mean (± standard deviation) age and body mass index (BMI) of all patients was 53.30±7.72 years and 27.3±5.37 kg/m, respectively. Patellar bone edema and patellar cysts demonstrated moderate inter-observer agreement. All cartilage features, trochlear bone edema and cysts, osteophytes, subchondral remodeling, patellar height, and synovitis demonstrated substantial inter-observer agreement. Patellofemoral alignment and total score demonstrated almost perfect inter-observer agreement (Table 2 and Figure 1). Conclusions: The novel MRI scoring system for PFOA proposed by the authors is an attempt to develop a comprehensive method to assess patellofemoral joint cartilage degeneration, including evaluation of patellar and trochlear cartilage changes, bony architecture, patellofemoral alignment, and synovitis. Importantly, all features of the scoring system demonstrated at least moderate inter-observer agreement, with the majority of variables and total score demonstrating substantial to near perfect agreement. Future studies should aim to validate this scoring system in patients with and without patellofemoral arthritis and attempt to correlate scores with clinical outcomes. [Table: see text][Table: see text]

Poster 126: Chronic ACL Injury Patients Have Lower Levels of Pro-Inflammatory Biomarkers in their Synovial Fluid and Worse ACLOAS Score at the Time of Surgery Than Those with Acute ACL Injury: A Cohort Study

Objectives: The relationship between structural abnormalities and inflammatory changes in the synovial fluid following ACL injury has not been well defined. The purpose of this study is to compare MRI findings and concentration of inflammatory biomarkers in the synovial fluid (SF) of acute and chronic anterior cruciate ligament (ACL) injury patients. Methods: Patients undergoing surgery for ACL injury from October 2011 to December 2021 were included in a database of patients who had SF samples collected at the time of surgery. From this cohort, 82 patients with acute ACL injury and 28 patients with chronic ACL injury were identified. All patients underwent a preoperative MRI examination of the knee and SF was aspirated from the operative knee prior to the surgical incision and concentrations of inflammatory biomarkers were quantified. MRI examinations were reviewed by a fellowship-trained musculoskeletal radiologist to assess radiographic features of acute and chronic knee injury using the validated ACLOAS system. Nonparametric tests were used to compare demographic factors, MRI findings, clinical symptoms, and SF inflammatory biomarkers between acute versus chronic ACL injury patients. A generalized linear model was used to assess the relationship of each SF biomarker with the ACLOAs subscores. Results: For acute ACL injury patients, mean time from injury to MRI and injury to surgery was 14 ± 35 days and 49 ± 38 days, respectively. The mean time from injury to MRI and injury to surgery was 3.2 ± 3.7 years and 3.4 ± 3.8 years, respectively, for those with chronic ACL injury. There were no significant demographic differences between groups; age (acute: 31.62 ± 8.02 years, chronic: 33.70 ± 10.60 years, p=0.130), sex (acute: 51.2% males, chronic: 57.1%, p=0.588), or body mass index (acute: 5.5 ± 4.4 kg/mm2, chronic: 25.3 ± 3.6 kg/mm2, p=0.931). Acute ACL injury patients had higher bone marrow edema severity scores (p&lt;0.001), Hoffa’s synovitis score (p=0.002), and effusion severity scores (p&lt;0.001). Chronic ACL injury patients had higher cartilage degeneration severity scores (p&lt;0.001), prevalence of meniscus tears (p=0.003), and meniscus tear severity scores (p&lt;0.001). Acute ACL injury patients had significantly higher synovial fluid levels of IL-6 (p=0.032), VEGF (p=0.002), TIMP1 (p&lt;0.001), IL1-RA (p=0.003), and MMP3 (p&lt;0.001) than chronic ACL injury patients. The generalized linear model revealed that after adjusting for age, sex, BMI, and time from injury to surgery, increased VEGF (p=0.003) and MMP3 (p=0.012) were associated with higher effusion score. MMP-3 was associated with a higher bone marrow edema score (p=0.034), and RANTES was associated with both a higher meniscus severity score (p=0.027) and increased cartilage lesions in the chronic ACL injury cohort. Conclusions: The findings from this study suggest that despite having more severe cartilage degeneration and a higher prevalence of meniscus pathology, chronic ACL injury patients had lower levels of synovial fluid inflammatory biomarkers at time of surgery compared to acute ACL injury patients. Additionally, we found that in chronic injuries, RANTES was associated with worse ACLOAS cartilage scores.

Poster 119: MRI evidence of labral tears in healthy young athletes without hip pain

Objectives: The prevalence of labral tears in asymptomatic active adults has been reported, but the prevalence of labral tears and other incidental hip lesions in the asymptomatic adolescent population has not yet been determined. The purpose of this study was to determine the prevalence of hip abnormalities detected on 3T MRI in an active adolescent population with no hip symptoms and, secondarily to compare with hip abnormalities found in adolescents who underwent an MRI for a hip related condition. Methods: Following IRB approval, adolescent patients presenting with isolated knee pain requiring knee MRI were prospectively recruited to have a 3T MRI of their asymptomatic contralateral hip (ASx). A comparison group of adolescent subjects who underwent an MRI for hip pain was enrolled retrospectively (Sx). All MRI scans were anonymized and randomized. Based on preliminary power analysis, 50 subjects were enrolled for each cohort. Blinded to the patient’s cohort status, clinical and demographic data, 2 fellowship-trained musculoskeletal radiologists evaluated these MRI’s independently for abnormal hip lesions, including labral tears. Inter-reader reliability was evaluated using Cohen’s Kappa. A chi-square or Fisher’s exact test was used to compare the prevalence of these hip lesions between the two cohorts. Results: Average patient age was 14.9 years for both cohorts (range 9-18 years); 52% were female. In the ASx group, incidental labral tears were found in 18%, labral/paralabral cysts 6%, cartilage lesion 0%, subchondral cyst 0%, ligamentum teres tear 0%, femoral fibrocystic change 0%, cam lesion 30%, acetabular bone edema 0%, acetabular rim fracture 0%. The prevalence of labral tears (30%, P-value 0.160) and cam lesion (36%, P-value 0.523) in the Sx group was not significantly different from that of the ASx cohort. Conclusions: Labral tears were present on 3T MRI’s of adolescents with and without hip pain. While MRI is essential to confirm the surgeon’s suspicion and to detect unexpected pathology, clinical exam and history are crucial in pinpointing clinically relevant abnormal imaging findings. [Table: see text]

Poster 264: Medial Tibia Bone Marrow Edema on Preoperative MRI Predicts Inferior Patient Outcomes Following Posterior Medial Meniscus Root Repair

Objectives: Repair of posterior medial meniscus root (PMMR) tears demonstrates favorable patient outcomes and may prevent rapid progression of knee osteoarthritis, however, there is a paucity of data in literature regarding prognostic factors affecting postoperative outcomes. The medial meniscus plays an important role in the knee biomechanically by increasing tibiofemoral contact area and decreasing peak tibiofemoral contact pressures. Few studies exist that examine preoperative knee magnetic resonance imaging (MRI) findings and patient reported outcome measures (PROMs) following PMMR repair. Semi-quantitative MRI evaluation can offer improved detection of degenerative pathology. Identifying specific factors that may predict surgical outcomes is important when considering PMMR repair, as some patients with more advanced degenerative joint disease may benefit from consideration for knee arthroplasty instead of joint preservation with meniscus repair surgery. The purpose of this study was to identify factors on preoperative MRI that may predict postoperative outcomes following PMMR repair. We hypothesize that patients with worse knee overall quality would have worse postoperative PRO scores. Methods: Between 2012 and 2020, patients who underwent posterior medial meniscus root repair at a tertiary referral academic center by fellowship trained sports medicine surgeons were retrospectively identified, recruited, and enrolled in the study. Institutional review board approval and informed consent was obtained. Inclusion criteria included patients ages 18-70, posterior medial meniscus root repair through transtibial fixation technique, minimum two years postoperative follow-up, and a preoperative knee MRI. Exclusion criteria included prior ipsilateral knee meniscus or ligamentous injury, additional ipsilateral knee injury requiring surgery, and conversion to knee arthroplasty. Visual Analog Scale (VAS) pain and PRO surveys including Patient Reported Outcome Measures Information System Physical Function (PROMIS-PF) Computer Adaptive Test, Lysholm Knee Score, Knee Osteoarthritis and Injury Outcome Score (KOOS) with 5 sub-sections, were collected at minimum 2-years postoperative. Patient Acceptable State Score (PASS) values from a prior meniscus study were utilized to identify patients that met PASS for the KOOS subsections. A fellowship-trained musculoskeletal radiologist reviewed preoperative MRIs and calculated Whole Organ Magnetic Resonance Imaging Scores (WORMS) for meniscus, cartilage, bone marrow edema pattern (BMEP) in 6 knee locations as well as effusion/synovitis and meniscal extrusion. Radiographs were scored with Kellgren-Lawrence (KL) scores to assess presence and severity of osteoarthritis. Statistical analysis was performed with Stata (StataCorp) using two sample T-tests, Mann-Whitney, and Fisher’s exact test for categorical variables. Significance was defined as p&lt;0.05. Results: We evaluated 29 knees (22 female patients) with a mean age at surgery of 52.3±9.9 years, body mass index of 27.6±5.6 kg/m2, and at a mean follow-up of 59.6 months ± 26.5. median KL grade 2, and 44.8% with meniscal extrusion. Pain scores decreased significantly from before surgery to final follow-up (p&lt;0.001), and the percentage of patients meeting PASS ranged from 44.8% for KOOS-Sport subscale to 72.4% for KOOS-Pain and KOOS-Quality of Life subscales (Table 1). There were 10 patients with medial tibial BMEP on pre-operative MRI and 19 with no medial tibial BMEP (Table 2). Patients with medial tibia BMEP had significantly lower Lysholm Knee Score (p=0.037), KOOS-Symptoms (p=0.028), and KOOS-QOL (p=0.029) (Figure 1). There were no significant differences in demographics between those with and without medial tibia BMEP. There was no significant difference in PRO scores when comparing those with medial femoral condyle BMEP, cartilage quality in any of the knee regions, or presence of meniscus extrusion. Conclusions: We observed that patients with medial tibia BMEP at baseline on their preoperative MRI had inferior PROMs for Lysholm Knee Score, KOOS Symptoms, and KOOS-QOL after PMMR repair compared to those without medial tibia BMEP. The presence of medial tibial BMEP could represent underlying damage that may not be evident in the cartilage itself, given most medial tibia cartilage was normal on MRI and cartilage quality was not a significant discriminant for outcomes. The presence of meniscus extrusion did not correlate with patient outcomes either. Limitations of this study include only VAS-Pain score as a pre-operative measure. Multivariate analysis was not possible due to the sample size available. A strength of this study is the mean follow up of approximately 5 years and preoperative MRI data on all patients. Posterior medial meniscus root tears are generally treated with surgical repair due to increased risk of progression to arthritis, however, some patients continue to have symptoms after repair. Our results show that patients with medial tibial BMEP on their preoperative MRI have worse PRO scores after posterior medial meniscus root repair, which can help surgeons better counsel patients towards optimal treatment options. In conclusion, the presence of medial tibia BMEP on preoperative MRI was a marker for inferior patient outcomes for Lysholm Knee Score, KOOS Symptoms, and QOL at minimum two years postoperative following posterior medial meniscus root repair. [Table: see text][Table: see text]

METAL ARTIFACT REDUCTION SEQUENCE MRI ABNORMALITIES IN ASYMPTOMATIC PATIENTS WITH DUAL MOBILITY HIP PROSTHESES

Modular dual mobility (DM) articulations are increasingly utilized during total hip arthroplasty (THA). However, concerns remain regarding the metal liner modularity. This study aims to correlate metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) abnormalities with serum metal ion levels in patients with DM articulations.All patients with an asymptomatic, primary THA and DM articulation with &gt;2-year follow-up underwent MARS-MRI of the operative hip. Each patient had serum cobalt, chromium, and titanium levels drawn. Patient satisfaction, Oxford Hip Score, and Forgotten Joint Score-12 (FJS-12) were collected. Each MARS-MRI was independently reviewed by fellowship-trained musculoskeletal radiologists blinded to serum ion levels.Forty-five patients (50 hips) with a modular DM articulation were included with average follow-up of 3.7±1.2 years. Two patients (4.4%) had abnormal periprosthetic fluid collections on MARS-MRI with cobalt levels &gt;3.0 μg/L. Four patients (8.9%) had MARS-MRI findings consistent with greater trochanteric bursitis, all with cobalt levels &lt; 1.0 μg/L. A seventh patient had a periprosthetic fluid collection with normal ion levels. Of the 38 patients without MARS-MRI abnormalities, 37 (97.4%) had cobalt levels &lt;1.0 μg/L, while one (2.6%) had a cobalt level of 1.4 μg/L. One patient (2.2%) had a chromium level &gt;3.0 μg/L and a periprosthetic fluid collection. Of the 41 patients with titanium levels, five (12.2%) had titanium levels &gt;5.0 μg/L without associated MARS-MRI abnormalities.Periprosthetic fluid collections associated with elevated serum cobalt levels in patients with asymptomatic dual mobility articulations occur infrequently (4.4%), but further assessment of these patients is necessary.Level of Evidence: Level IV

MRI Findings Associated With Anterior Cruciate Ligament Tears in National Football League Athletes.

Anterior cruciate ligament (ACL) tears are a high-frequency injury requiring a lengthy recovery in professional American football players. Concomitant pathology associated with ACL tears as identified on magnetic resonance imaging (MRI) is not well understood in these athletes. To describe the MRI findings of concomitant injuries associated with ACL tears among athletes in the National Football League (NFL). Cross-sectional study; Level of evidence, 3. Of 314 ACL injuries in NFL athletes from 2015 through 2019, 191 complete MRI scans from the time of primary ACL injury were identified and reviewed by 2 fellowship-trained musculoskeletal radiologists. Data were collected on ACL tear type and location, as well as presence and location of bone bruises, meniscal tears, articular cartilage pathology, and concomitant ligament pathology. Mechanism data from video review were linked with imaging data to assess association between injury mechanism (contact vs noncontact) and presence of concomitant pathology. Bone bruises were evident in 94.8% of ACL tears in this cohort, most often in the lateral tibial plateau (81%). Meniscal, additional ligamentous, and/or cartilage injury was present in 89% of these knees. Meniscal tears were present in 70% of knees, lateral (59%) more than medial (41%). Additional ligamentous injury was present in 71% of all MRI scans, more often a grade 1/2 sprain (67%) rather than a grade 3 tear (33%), and most often involving the medial collateral ligament (MCL) (57%) and least often the posterior cruciate ligament (10%). Chondral damage was evident in 49% of all MRI scans, with ≥1 full-thickness defect in 25% of all MRI scans, most often lateral. Most (79%) ACL tears did not involve direct contact to the injured lower extremity. Direct contact injuries (21%) were more likely to have a concomitant MCL tear and/or medial patellofemoral ligament injury and less likely to have a medial meniscal tear. ACL tears were rarely isolated injuries in this cohort of professional American football athletes. Bone bruises were almost always present, and additional meniscal, ligamentous, and chondral injuries were also common. MRI findings varied by injury mechanism.

Management of Partial-Thickness Tears of the Distal Bicep Tendon: Evaluation of 111 Patients With 10-Year Follow-up.

There is a paucity of research on the management of partial-thickness tears of the distal bicep tendon, and even less is known about the long-term outcomes of this condition. To identify patients with partial-thickness distal bicep tendon tears and determine (1) patient characteristics and treatment strategies, (2) long-term outcomes, and (3) any identifiable risk factors for progression to surgery or complete tear. Case-control study; Level of evidence, 3. A fellowship-trained musculoskeletal radiologist identified patients diagnosed with a partial-thickness distal bicep tendon tear on magnetic resonance imaging between 1996 and 2016. Medical records were reviewed to confirm the diagnosis and record study details. Multivariate logistic regression models were created using baseline characteristics, injury details, and physical examination findings to predict operative intervention. In total, 111 patients met inclusion criteria (54 treated operatively, 57 treated nonoperatively), with 53% of tears in the nondominant arm and a mean follow-up time after surgery of 9.7 ± 6.5 years. Only 5% of patients progressed to full-thickness tears during the study period, at a mean of 35 months after the initial diagnosis. Patients who were nonoperatively treated were less likely to miss time from work (12% vs 61%; P < .001) and missed fewer days (30 vs 97 days; P < .016) than those treated surgically. Multivariate regression analyses demonstrated increased risk of progression to surgery with older age at initial consult (unit odds ratio [OR], 1.1), tenderness to palpation (OR, 7.5), and supination weakness (OR, 24.8). Supination weakness at initial consult was a statistically significant predictor for surgical intervention (OR, 24.8; P = .001). Clinical outcomes were favorable for patients regardless of treatment strategy. Approximately 50% of patients were treated surgically; patients with supination weakness were 24 times more likely to undergo surgery than those without. Progression to full-thickness tear was a relatively uncommon reason for surgical intervention, with only 5% of patients progressing to full-thickness tears during the study period and the majority occurring within 3 months of initial diagnosis.

Ultrasound-guided tenotomy for lateral epicondylitis with TenJet improves physical functional and decreased pain outcomes at 1 year: a case series review

Common extensor tendinopathy is a common cause of lateral elbow pain. Ultrasound-guided minimally invasive tenotomy (MIT) has been utilized successfully as a treatment for several years, but the use of TenJet device has not been well described. To evaluate the effectiveness and safety of MIT with TenJet who failed nonsurgical management of common extensor tendinopathy in an outpatient setting. A total of 100 patients with common extensor tendinopathy who failed conservative treatment underwent ultrasound-guided MIT with TenJet device in the outpatient setting at a single institution. All 100 patients prior to MIT underwent diagnostic musculoskeletal ultrasound showing common extensor tendinosis. The findings were interpreted by a fellowship-trained and board-certified musculoskeletal radiologist. Patients were evaluated with the Oxford Elbow Score prior to the procedure and at 1-year follow-up. Exclusion criteria included prior corticosteroid injection within the past 6 weeks of the MIT intervention, active local or systemic infection, complete full thickness tear of the common extensor tendon, and pregnancy. Oxford Elbow Score had a statistically significant difference in baseline to 1 year (P<.001). No complications were reported and zero patients went on to require open surgical intervention. MIT with TenJet is a safe, effective, and well-tolerated treatment for common extensor tendinopathy.