BACKGROUND: Knee injuries are prevalent, and early diagnosis is crucial for guiding clinical therapy. MRI is the diagnostic gold standard for bone marrow edema (BME) in patients with acute knee injuries, yet there are still limitations. Dual-energy CT, a possible viable replacement, is being explored (DECT).
METHODS: We systematically retrieved studies from EMBASE, Scopus, PUBMED, and the Cochrane Library and collected gray literatures. In accordance with the PRISMA-DTA standards, a systematic review was conducted between the study\'s initiation and July 31, 2021, utilizing an MRI reference standard and at least 10 adult patients with acute knee injuries to evaluate the diagnostic effectiveness of DECT for diagnosing BME. Two reviewers collected the study\'s details independently. For the meta-analysis, a bivariate mixed-effects regression model was utilized, and subgroup analysis was employed to determine the sources of variability.
RESULTS: The research included nine studies that examined 290 individuals between the ages of 23 and 53 with acute knee injuries who had DECT and MRI. Overall, the sensitivity, specificity, and AUC of the BME were 85% (95% confidence interval [CI]: 77-90%), 96% (95% CI: 93-97%), and 0.97 (95% CI: 0.95-0.98), respectively. To account for the assumed diversity of research, there were no statistically significant differences between the comparison groups in terms of specificity and sensitivity.
CONCLUSIONS: DECT is a viable alternative to MRI for individuals with acute knee injuries when MRI is inappropriate or unavailable.

OBJECTIVE: This study evaluated the ability of a custom dual-energy CT (DECT) post-processing material decomposition method to image bone marrow edema after acute knee injury. Using an independent validation cohort, the DECT method was compared to gold-standard, fluid-sensitive MRI. By including both quantitative voxel-by-voxel validation outcomes and semi-quantitative radiologist scoring-based assessment of diagnostic accuracy, we aimed to provide insight into the relationship between quantitative metrics and the clinical utility of imaging methods.
METHODS: Images from 35 participants with acute anterior cruciate ligament injuries were analyzed. DECT material composition was applied to identify bone marrow edema, and the DECT result was quantitatively compared to gold-standard, registered fluid-sensitive MRI on a per-voxel basis. In addition, two blinded readers rated edema presence in both DECT and fluid-sensitive MR images for evaluation of diagnostic accuracy.
RESULTS: Semi-quantitative assessment indicated sensitivity of 0.67 and 0.74 for the two readers, respectively, at the tibia and 0.55 and 0.57 at the femur, and specificity of 0.87 and 0.89 for the two readers at the tibia and 0.58 and 0.89 at the femur. Quantitative assessment of edema segmentation accuracy demonstrated mean dice coefficients of 0.40 and 0.16 at the tibia and femur, respectively.
CONCLUSIONS: The custom post-processing-based DECT method showed similar diagnostic accuracy to a previous study that assessed edema associated with ligamentous knee injury using a CT manufacturer-provided, built-in edema imaging application. Quantitative outcome measures were more stringent than semi-quantitative scoring methods, accounting for the low mean dice coefficient scores.

Musculoskeletal injuries often induce local accumulation of blood and/or fluid within the bone marrow, which is detected on medical imaging as edema-like marrow signal intensities (EMSI). In addition to its biological effects on post-injury recovery, the displacement of low-attenuating, largely adipocytic marrow by EMSI may introduce errors into quantitative computed tomography (QCT) measurements of bone mineral density (vBMD) and resulting bone stiffness estimates from image-based finite element (FE) analysis. We aimed to investigate the impact of post-injury changes in marrow soft tissue composition on CT-based bone measurements by applying CT imaging at multiple spatial resolutions. To do so, dual energy QCT (DECT) material decomposition was used to detect EMSI in the tibiae of nineteen participants with a recent anterior cruciate ligament tear. We then measured bone density and FE-based apparent modulus within the EMSI region and in a matched volume in the uninjured contralateral knee. Three measurement methods were applied: 1.) standard, QCT density calibration and density-based FEM; 2.) a DECT density calibration that provides density measurements adjusted for marrow soft tissues; and 3.) high-resolution peripheral QCT (HR-pQCT) density and microFE analyses. When measured using standard, single-energy QCT, vBMD and apparent modulus were elevated in the EMSI compared to the contralateral. After adjusting for marrow soft tissue composition using DECT, these measurements were no longer different between the two regions. By allowing for high-resolution, localized density analysis, HR-pQCT indicated that trabecular tissue mineral density was 9 mgHA/cm3 lower, while density of marrow soft tissues was 18 mgHA/cm3 higher, in the EMSI than the contralateral region, suggesting that EMSI have opposite effects on the measured density of trabecular bone and the underlying soft marrow. Thus, after an acute injury, altered composition of marrow soft tissues may artificially inflate overall measurements of bone density and apparent modulus obtained using standard QCT. This can be corrected by accounting for marrow soft tissue attenuation, either by using DECT-based density calibration or HR-pQCT microFE and measurements of local density of trabeculae.

OBJECTIVE: This study developed methods to quantify and improve the accuracy of dual-energy CT (DECT)-based bone marrow edema imaging using a clinical CT system. Objectives were: (a) to quantitatively compare DECT with gold-standard, fluid-sensitive MRI for imaging of edema-like marrow signal intensity (EMSI) and (b) to identify image analysis parameters that improve delineation of EMSI associated with acute knee injury on DECT images.
METHODS: DECT images from ten participants with acute knee injury were decomposed into estimated fractions of bone, healthy marrow, and edema based on energy-dependent differences in tissue attenuation. Fluid-sensitive MR images were registered to DECT for quantitative, voxel-by-voxel comparison between the two modalities. An optimization scheme was developed to find attenuation coefficients for healthy marrow and edema that improved EMSI delineation, compared to MRI. DECT method accuracy was evaluated by measuring dice coefficients, mutual information, and normalized cross correlation between the DECT result and registered MRI.
RESULTS: When applying the optimized three-material decomposition method, dice coefficients for EMSI identified through DECT vs MRI were 0.32 at the tibia and 0.13 at the femur. Optimization of attenuation coefficients improved dice coefficient, mutual information, and cross-correlation between DECT and gold-standard MRI by 48%-107% compared to three-material decomposition using non-optimized parameters, and improved mutual information and cross-correlation by 39%-58% compared to the manufacturer-provided two-material decomposition.
CONCLUSIONS: This study quantitatively evaluated the performance of DECT in imaging knee injury-associated EMSI and identified a method to optimize DECT-based visualization of complex tissues (marrow and edema) whose attenuation parameters cannot be easily characterized. Further studies are needed to improve DECT-based EMSI imaging at the femur.

BACKGROUND: To study the role of lysosomal decomposition and elimination of old bone matrix, as well as the mechanism of promoting chondrocyte growth and bone recovery through the perspective of TFEB-mediated lysosomal autophagy.
METHODS: Rat models of acute knee injury were designed, and autophagy flow was detected by injection of autophagy inhibitors 3-methyladenine. Autophagy flow was detected by RFP-GFP-LC3 double fluorescence molecule. The expression of TFEB, DRAM, MAPLC3, and MITF were analyzed by Western blot, and the expression of genes NITF, Bcl2, and TYR in rat cartilage tissues were detected by RT-PCR.
RESULTS: The number of autophagosomes was increasing in the auto group compared with the inhibitor-auto group and normal group. There was a significant difference of LC3 levels in the auto group and inhibitor-auto group compared with the normal control. The expression of TFEB, DRAM, MAPLC3, and MITF proteins by Western blot analysis were significantly increased in the auto group and decreased in the inhibitor-auto group. The expression of NITF, Bcl2, and TYR by RT-PCR determination were higher in the auto group and inhibitor-auto group than the normal group.
CONCLUSIONS: Autophagy can inhibit apoptosis, promote chondrocyte growth and bone regeneration, and restore knee joint injury of rats. The main mechanism is to promote the effect of TFEB-mediated lysosomal autophagy.

BACKGROUND: Recent work suggests that reconstruction of the ruptured anterior cruciate ligament within 12 months of injury results in better outcomes. We present a complete audit cycle examining the effect of establishment of an Acute Knee Clinic on time to surgery.
METHODS: Records of 20 anterior cruciate ligament reconstructions undertaken by the senior author between June 2003 and May 2004 were examined to identify the time to surgery. The Acute Knee Clinic was established in December 2004. Prospectively collected data on patients attending the Acute Knee Clinic between May 2005 and July 2007 and patients undergoing anterior cruciate ligament reconstruction from September 2006 to 2007 were reviewed with respect to referral route, time from injury to specialist review and time to surgery.
RESULTS: Mean time from injury to surgery of the initial cohort was 14 months (range 3-56). After establishment of the Acute Knee Clinic, 90% of referrals from Accident and Emergency (A&E) were seen by a specialist within four weeks. Between September 2006 and September 2007, 49 patients underwent anterior cruciate ligament reconstruction: 21 came via the Acute Knee Clinic, with a mean time from injury to surgery of 6 months; 28 patients from the elective clinic had a mean time to surgery of 25 months. 95% of Acute Knee Clinic patients and 53 % of elective clinic patients had surgery within 12 months of injury.
CONCLUSIONS: The Acute Knee Clinic has been shown to reduce the time from injury to anterior cruciate ligament reconstruction. The Acute Knee Clinic only accounts for the referral of 40% of anterior cruciate ligament reconstructions in this series: Further education work is required with A&E staff and GPs regarding the referral of knee injuries. Access to the Acute Knee Clinic could be extended to GPs, although this could create service overload.

Current government policy aims to deliver high quality healthcare by recording accurate data at the point of giving care, storing it efficiently and displaying it in a format, which is easily interpreted by healthcare professionals and patients. Few published reports describe the benefits of collecting and reporting such data from the point of view of the patient. We report the case of a 62-year-old lorry driver who used a web-based system to track patient reported outcome measures (PROMs) following an acute knee injury to full recovery over a 24-month period. The system reports clinical outcome scores in real-time to the patient and their medical team, clearly illustrating and enhancing recovery from injury. This case reveals how local software meets the needs of the individual patient linking and integrating such local systems must be the future focus of eHealth within the NHS to release the benefits presented by the information revolution.

BACKGROUND: The routine use of magnetic resonance imaging (MRI) for the assessment of acute knee injuries is controversial. The goal of this study is to present an audit of patients seen in a dedicated Acute Knee Injury Clinic (AKIC) to determine the frequency and appropriateness of MRI utilization.
METHODS: A retrospective review identified all patients who had an MRI and a randomly selected control group without MRI. The MRI was classified based on whether it was ordered by the AKIC team or by an external clinician. The consensus-based \'Indications for Urgent MRI in Acute Soft Tissue Knee Problems\' were applied to both groups. An MRI was considered appropriate if any of the indications were met.
RESULTS: The overall MRI utilization rate was 23% (142/611). Of the MRIs performed, 32% (46/142) met the indications. About 94% (33/35) of the MRIs ordered by the AKIC experts met the indications, compared to only 12% (13/107) of those ordered externally. No patients in the control group met the indications. Diagnoses were similar between groups.
CONCLUSIONS: These results suggest that application of guidelines by experts in knee evaluation can significantly reduce expensive MRI utilization in patients with acute knee injuries without negatively impacting the appropriate diagnosis and disposition.