Faculty Bibliography

PURPOSE/OBJECTIVE:To evaluate long-term outcomes of patients treated with posterior medial meniscal root tear (PMMRT) repair through assessment of functional outcome scores and to identify patient surgical and magnetic resonance imaging (MRI) characteristics associated with improved outcomes. METHODS:This was a single-centre, retrospective study evaluating patients who had undergone a PMMR repair using a transtibial suture pullout technique with two locking cinch sutures. This was performed as a follow-up to previously published 2-year and 5-year outcome studies, using the same cohort. All patients from the prior short-term and midterm studies were invited to participate. Patient-reported outcome (PROs) scores, including the International Knee Documentation Committee (IKDC) and Lysholm scores, were collected. Previously collected demographic data were updated based on review of the electronic medical record. Patient outcomes were assessed preoperatively, as well as at 2-year, 5-year and 8-year postoperatively. MRI outcome measurements were assessed at 2-year and 5-year follow-ups. All statistical analysis was performed using SPSS version 26. RESULTS:Seventeen patients of the original 18 patients (94.4%) were included in the final analysis. Additionally, three patients who had additional ipsilateral surgery were excluded from the analysis of PROs. The IKDC score significantly increased from 44.7 ± 11.6 at preoperative baseline to 71.2 ± 21.3 at 8-year post-operation (p = 0.001). There were no significant differences in IKDC score between 2-year and 8-year follow-ups (p = n.s.) or 5-year and 8-year follow-ups (p = n.s.). The Lysholm score significantly increased from 49.6 ± 7.3 at preoperative baseline to 76.4 ± 17.2 at 8-year follow-up (p < 0.001). There was no significant difference in Lysholm scores between 2-year and 8-year follow-ups (p = n.s.) or 5-year and 8-year follow-ups (p = n.s.). A linear regression analysis found that 5-year IKDC scores were significantly correlated with 8-year IKDC scores (β = 0.681, p = 0.038). At 8-year follow-up, four (23.5%) patients required additional procedures on their operative knee (one total knee arthroplasty conversion). CONCLUSION/CONCLUSIONS:Patients treated with repair of PMMRT had maintenance of clinical outcome improvements at long-term follow-up despite worsening MRI outcomes at short-term and medium-term follow-ups. While a high proportion of patients required additional procedures on their operative knee at 8-year follow-up, few of these patient's additional procedures were related to failure of their primary surgery. Providers and patients may expect durable clinical outcomes following the repair of PMMRT, irrespective of radiographic appearance. LEVEL OF EVIDENCE/METHODS:Level IV.

PURPOSE/OBJECTIVE:The aim of this study was to use the National Ambulatory Medical Care Survey database to assess MRI utilization in patients 50 years and older with atraumatic hip or knee pain. METHODS:National Ambulatory Medical Care Survey weighted survey data (2007-2019) were obtained for ambulatory visits in patients 50 years and older with atraumatic hip or knee pain. The outcome variable was MRI ordering status, and analyzed characteristics included patient age, race/ethnicity, payer, physician specialty, metropolitan statistical area, and a coexistent radiography order. Multivariable logistic regressions were conducted to assess the association between MRI ordering status and the analyzed patient characteristics. All tests were two sided, and P values ≤.05 were considered to indicate statistical significance. RESULTS:In total, 88,978,804 knee pain and 28,675,725 hip pain patient visits (survey weighted) were analyzed, with 4,690,943 (5.3%) and 2,023,226 (7.1%) having knee or hip MRI orders, respectively. Overall, 2,454,433 knee pain visits (2.8%) and 575,155 hip pain visits (2.0%) had orders for both MRI and radiographs. Black patients (P = .03) and patients 80 years and older (P = .04) were less likely to have knee MRI ordered, whereas uninsured patients were less likely to have hip MRI ordered (P = .01). Patients with hip pain were more likely to have hip MRI ordered if seen by a surgical subspecialist (P = .01). CONCLUSIONS:A low proportion of MRI examinations were ordered for visits in patients 50 years and older with atraumatic hip or knee pain. Groups with lower health care access were less likely to have an MRI order, highlighting known disparities in health care equity.

Imaging plays an important role in the workup of musculoskeletal infection, in conjunction with clinical history and physical exam. There are multiple imaging modalities that can be of clinical utility in the setting of suspected infection, each with their own benefits and limitations. Radiography is a low-cost, accessible modality providing a broad osseous overview, but can be insensitive for early osteomyelitis. Ultrasound plays a more limited role in the workup of musculoskeletal infection, but can be useful in the pediatric population or for real-time guidance for joint and soft tissue aspirations. Computed tomography (CT) plays an important role in the timely and accurate diagnosis of critically ill patients in the emergency setting. Its superior soft tissue characterization allows for diagnosis of abscesses, and it can help confirm the clinical diagnosis of necrotizing fasciitis when soft tissue gas is present. Magnetic resonance imaging (MRI) is often the modality of choice in the diagnosis of infection, as its superior contrast resolution allows for clear delineation of the presence and extent of both soft tissue infection and osteomyelitis. Additionally, the use of intravenous contrast and advanced imaging sequences such as diffusion weighted imaging (DWI) further increases the diagnostic utility of MRI in the assessment for infection. Familiarity with the diagnostic utility of each imaging modality will allow the radiologist to appropriately guide imaging workup in the setting of clinically suspected infection.

PURPOSE/OBJECTIVE:The purpose of this study is to investigate the anatomic distribution of bone marrow edema on MRI among patients who sustained a Segond fracture compared to those with an isolated ACL tear. METHODS:A retrospective cohort study was performed of patients aged 18-40 years old who presented with an acute isolated ACL tear between January 2012 and May 2022. Two blinded readers reviewed all knee MRIs to assess bone marrow edema using the Whole-Organ Magnetic Resonance Imaging Score and the area of each sub-compartment was scored. RESULTS:There were 522 patients in the final analysis, of which 28 patients (5.4%) were identified to have a Segond fracture. The Segond group demonstrated significantly greater rates of WORMS grades 2 and 3 in the central lateral femoral condyle, as well as the anterior, central, and posterior lateral tibial plateau. Furthermore, the Segond group demonstrated significantly greater rates of WORMS grades 2 and 3 in the central medial femoral condyle and the anterior medial tibial plateau. Bone edema at the central lateral femoral condyle (R = 0.034, p = 0.019) and central tibial plateau (R = 0.093, p = 0.033) were significantly correlated with lateral meniscus tears, while the edema in the posterior medial femoral condyle was correlated with medial meniscus tears (R = 0.127, p = 0.004). CONCLUSION/CONCLUSIONS:Patients who present with ACL tear and a concomitant Segond fracture demonstrate significantly more extensive bone marrow edema in both the medial and lateral compartments of the knee compared to patients with an isolated ACL tear.

Background Current terms used to describe the MRI findings for musculoskeletal infections are nonspecific and inconsistent. Purpose To develop and validate an MRI-based musculoskeletal infection classification and scoring system. Materials and Methods In this retrospective cross-sectional internal validation study, a Musculoskeletal Infection Reporting and Data System (MSKI-RADS) was designed. Adult patients with radiographs and MRI scans of suspected extremity infections with a known reference standard obtained between June 2015 and May 2019 were included. The scoring categories were as follows: 0, incomplete imaging; I, negative for infection; II, superficial soft-tissue infection; III, deeper soft-tissue infection; IV, possible osteomyelitis (OM); V, highly suggestive of OM and/or septic arthritis; VI, known OM; and NOS (not otherwise specified), nonspecific bone lesions. Interreader agreement for 20 radiologists from 13 institutions (intraclass correlation coefficient [ICC]) and true-positive rates of MSKI-RADS were calculated and the accuracy of final diagnoses rendered by the readers was compared using generalized estimating equations for clustered data. Results Among paired radiographs and MRI scans from 208 patients (133 male, 75 female; mean age, 55 years ± 13 [SD]), 20 were category I; 34, II; 35, III; 30, IV; 35, V; 18, VI; and 36, NOS. Moderate interreader agreement was observed among the 20 readers (ICC, 0.70; 95% CI: 0.66, 0.75). There was no evidence of correlation between reader experience and overall accuracy (P = .94). The highest true-positive rate was for MSKI-RADS I and NOS at 88.7% (95% CI: 84.6, 91.7). The true-positive rate was 73% (95% CI: 63, 80) for MSKI-RADS V. Overall reader accuracy using MSKI-RADS across all patients was 65% ± 5, higher than final reader diagnoses at 55% ± 7 (P < .001). Conclusion MSKI-RADS is a valid system for standardized terminology and recommended management of imaging findings of peripheral extremity infections across various musculoskeletal-fellowship-trained reader experience levels. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Schweitzer in this issue.

OBJECTIVE:The purpose of this study was to compare the short-term clinical outcomes of matrix-induced autologous chondrocyte implantation (MACI) to those seen following traditional autologous chondrocyte implantation (ACI) in the management of symptomatic cartilage lesions of the knee. METHODS:This was a retrospective cohort study of patients who underwent either ACI or MACI from January 2011 to March 2018. Patients with a minimum postoperative follow-up of 18 months were contacted. Demographic information, intraoperative findings, and patient-reported functional outcomes scores were collected. Comparisons were made between the two cell-based cartilage repair techniques. RESULTS:Fifty-six patients were included in the study (39 ACI, 17 MACI). Visual analog scale (VAS) for pain scores improved significantly in both groups, with MACI patients demonstrating significantly lower postoperative pain scores compared to those treated with ACI. In the ACI group, there was a decrease in the Tegner Activity score compared to the preoperative baseline, while no significant difference was seen between pre- and postoperative activity levels in the MACI group. Patients were generally satisfied with the outcome of their procedures, and there was no significant difference in satisfaction between groups. No patients re-quired additional surgery during the follow-up period. CONCLUSION/CONCLUSIONS:Both ACI and MACI demonstrated good short-term postoperative clinical results with improved pain and activity levels compared to the preoperative baseline. Patients treated with the MACI technique demonstrated greater reductions in pain scores compared to ACI, and while ACI resulted in a decrease in levels of postoperative activity, activity levels for MACI remained stable.

OBJECTIVE:To determine the cost-effectiveness of rotator cuff hydroxyapatite deposition disease (HADD) treatments. METHOD/METHODS:A 1-year time horizon decision analytic model was created from the US healthcare system perspective for a 52-year-old female with shoulder HADD failing conservative management. The model evaluated the incremental cost-effectiveness ratio (ICER) and net monetary benefit (NMB) of standard strategies, including conservative management, ultrasound-guided barbotage (UGB), high- and low-energy extracorporeal shock wave therapy (ECSW), and surgery. The primary effectiveness outcome was quality-adjusted life years (QALY). Costs were estimated in 2022 US dollars. The willingness-to-pay (WTP) threshold was $100,000. RESULTS:For the base case, UGB was the preferred strategy (0.9725 QALY, total cost, $2199.35, NMB, $95,048.45, and ICER, $33,992.99), with conservative management (0.9670 QALY, NMB $94,688.83) a reasonable alternative. High-energy ECSW (0.9837 QALY, NMB $94,805.72), though most effective, had an ICER of $121, 558.90, surpassing the WTP threshold. Surgery (0.9532 QALY, NMB $92,092.46) and low-energy ECSW (0.9287 QALY, NMB $87,881.20) were each dominated. Sensitivity analysis demonstrated that high-energy ECSW would become the favored strategy when its cost was < $2905.66, and conservative management was favored when the cost was < $990.34. Probabilistic sensitivity analysis supported the base case results, with UGB preferred in 43% of simulations, high-energy ECSW in 36%, conservative management in 20%, and low-energy ECSW and surgery in < 1%. CONCLUSION/CONCLUSIONS:UGB appears to be the most cost-effective strategy for patients with HADD, while surgery and low-energy ECSW are the least cost-effective. Conservative management may be considered a reasonable alternative treatment strategy in the appropriate clinical setting.

OBJECTIVE:Concerns regarding patient safety and image quality have made the use of knee-spanning external fixators in MRI a challenging clinical scenario. The purpose of our study was to poll practicing musculoskeletal radiologists on their personal experiences regarding the use of knee-spanning external fixators in MRI in an effort to consolidate practice trends for the radiologists' benefit. METHODS:A 27-item survey was created to address the institutional use, safety, adverse events, quality, and perspectives of the radiologist related to MRI of an externally fixated knee. The survey was distributed to 1739 members of the Society of Skeletal Radiology. RESULTS:A total of 72 members of the Society of Skeletal Radiology completed the survey. Most notably, 40 of 72 (55.56%) respondents are permitted to place a knee-spanning external fixator inside the MR bore at their institution, while19 of 72 (26.39%) respondents are not permitted to do so. Fourteen of 32 (43.75%) respondents have institutional guidelines for safely performing an MRI of an externally fixated knee. Twenty-five of 32 (78.13%) respondents are comfortable permitting an MRI of an externally fixated knee. CONCLUSION/CONCLUSIONS:We found a general lack of consensus regarding the decision to scan a patient with a knee-spanning external fixator in MRI. Many institutions lack safety guidelines, and providers rely upon a heterogeneous breadth of resources for safety information. A re-examination of the FDA device labeling nomenclature and expectations of the individual manufacturers may be needed to bridge this gap and help direct management decisions placed upon the provider.

PURPOSE/OBJECTIVE:To characterize the safety, efficacy, and potential role of genicular artery embolization (GAE) as a disease-modifying treatment for symptomatic knee osteoarthritis (OA). MATERIALS AND METHODS/METHODS:This is an interim analysis of a prospective, single-arm clinical trial of patients with symptomatic knee OA who failed conservative therapy for greater than 3 months. Sixteen patients who underwent GAE using 250-μm microspheres and had at least 1 month of follow-up were included. Six patients completed the 12-month follow-up, and 10 patients remain enrolled. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was evaluated at baseline and at 1, 3, and 12 months. Serum and plasma samples were collected for biomarker analysis. The primary end point was the percentage of patients who achieved the minimal clinically important difference (MCID) for WOMAC pain score at 12 months. Baseline and follow-up outcomes were analyzed using the Wilcoxon matched-pairs signed-rank test. RESULTS:Technical success of the procedure was 100%, with no major adverse events. The MCID was achieved in 5 of the 6 (83%) patients at 12 months. The mean WOMAC pain score decreased from 8.6 ± 2.7 at baseline to 4.9 ± 2.7 (P = .001), 4.4 ± 2.8 (P < .001), and 4.7 ± 2.7 (P = .094) at 1, 3, and 12 months, respectively. There was a statistically significant decrease in nerve growth factor (NGF) levels at 12 months. The remaining 8 biomarkers showed no significant change at 12 months. CONCLUSIONS:GAE is a safe and efficacious treatment for symptomatic knee OA. Decreased NGF levels after GAE may contribute to pain reduction and slowing of cartilage degeneration.