Diagnostic performance of dual-energy CT in detecting bone marrow edema in lower limb joint injuries: a meta-analysis.

OBJECTIVE: We aimed to evaluate the diagnostic performance of dual-energy computed tomography (DECT) in detecting bone marrow edema (BME) in patients with lower limb joint injuries. METHODS: A thorough literature search was conducted across the PubMed, Embase, and Web of Science databases to identify relevant studies up to April 2024. Studies examining the diagnostic performance of DECT in detecting BME in lower limb joint injuries patients were included. Sensitivity and specificity were evaluated using the inverse variance method and transformed via the Freeman-Tukey double arcsine transformation. Furthermore, the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool was utilized to evaluate the methodological quality of the included studies. RESULTS: This meta-analysis included 17 articles involving 625 patients. The pooled sensitivity, specificity, and AUC for DECT in detecting BME in lower limb joint injuries patients were 0.82 (95 % CI: 0.76-0.87), 0.95 (95 % CI: 0.92-0.97), and 0.95 (95 % CI: 0.93-0.97), respectively. The pooled sensitivity of DECT for detecting BME in knee, hip, and ankle joint injuries was 0.80, 0.84, and 0.80, with no significant difference among these joints (P = 0.55). The pooled specificity for knee, hip, and ankle injuries was 0.95, 0.97, and 0.89. Specificity differed significantly among the joints (P < 0.01), with the highest specificity in hip injuries. CONCLUSIONS: Our meta-analysis indicates that DECT demonstrates high diagnostic performance in detecting BME in patients with lower limb joint injuries, with the highest specificity observed in hip joint injuries. To validate these findings, further larger prospective studies are necessary.

Evaluation of magnetic resonance thermometry performance during MR-guided hyperthermia treatment of soft-tissue sarcomas in the lower extremities and pelvis.

INTRODUCTION: This study evaluated the performance of magnetic resonance thermometry (MRT) during deep-regional hyperthermia (HT) in pelvic and lower-extremity soft-tissue sarcomas. MATERIALS AND METHODS: 17 pelvic (45 treatments) and 16 lower-extremity (42 treatments) patients underwent standard regional HT and chemotherapy. Pairs of double-echo gradient-echo scans were acquired during the MR protocol 1.4 s apart. For each pair, precision was quantified using phase data from both echoes ('dual-echo') or only one ('single-echo') in- or excluding body fat pixels in the field drift correction region of interest. The precision of each method was compared to that of the MRT approach using a built-in clinical software tool (SigmaVision). Accuracy was assessed in three lower-extremity patients (six treatments) using interstitial temperature probes. The Jaccard coefficient quantified pretreatment motion; receiver operating characteristic analysis assessed its predictability for acceptable precision (<1 °C) during HT. RESULTS: Compared to the built-in dual-echo approach, single-echo thermometry improved the mean temporal precision from 1.32 ± 0.40 °C to 1.07 ± 0.34 °C (pelvis) and from 0.99 ± 0.28 °C to 0.76 ± 0.23 °C (lower extremities). With body fat-based field drift correction, single-echo mean accuracy improved from 1.4 °C to 1.0 °C. Pretreatment bulk motion provided excellent precision prediction with an area under the curve of 0.80-0.86 (pelvis) and 0.81-0.83 (lower extremities), compared to gastrointestinal air motion (0.52-0.58). CONCLUSION: Single-echo MRT exhibited better precision than dual-echo MRT. Body fat-based field-drift correction significantly improved MRT accuracy. Pretreatment bulk motion showed improved prediction of acceptable MRT temporal precision over gastrointestinal air motion.

Applications of SPECT and PET Imaging for the Physiological Evaluation of Lower Extremity Peripheral Artery Disease.

Peripheral artery disease (PAD) is classified as the narrowing or complete occlusion of the lower extremity arteries due to atherosclerosis. The risk of developing PAD increases with increased age and risk factors such as smoking, diabetes, hypertension, and hypercholesterolemia. Current treatment for PAD involves lifestyle and symptom management, statin and antiplatelet therapy, and/or surgical interventions to improve quality of life with varying efficacy. PAD affects approximately 5 to 6 percent of the global population, with this global burden continuing to increase. Despite the increase in disease prevalence, no gold standard functional diagnostic tool has been established for enabling early detection of the disease, appropriate medical management, and prediction of adverse outcomes for PAD patients. The visualization and quantification of the physiological consequences of PAD are possible by way of nuclear imaging: specifically, via scintigraphy, single-photon emission computed tomography (SPECT), and positron emission tomography (PET) imaging. These non-invasive modalities, when combined with targeted radionuclides, possess utility for detecting functional perfusion deficits and provide unique insight into muscle tissue- and vascular-level characteristics of PAD patients. This review discusses the past, present, and emerging applications of hybrid nuclear imaging modalities in the evaluation and monitoring of patients with PAD.

Magnetic resonance lymphography findings across different clinical stages of lower limb lymphedema.

OBJECTIVE: To investigate the findings on lower limb lymphedema using magnetic resonance lymphography (MRL). METHODS: MRL was used to record the lymphatic vessel morphology, distribution of lymphatic vessels, dermal backflow (DBF), and morphology of inguinal lymph nodes in 112 patients (175 affected limbs) with lower limb lymphedema at different clinical stages (according to the International Society of Lymphology staging criteria 2020). RESULTS: The lymphatic vessel morphology significantly differed at different clinical stages (X2 =59.306; P = 0.000). ISL stage I is dominated by "scattered beads" and "branch-like" distribution, ISL stage Ⅱ has tree branch or "capillary-like" distribution, and ISL stage Ⅲ primarily has a capillary pattern and contrast agent accumulation in the foot. There were statistically significant differences in the distribution of lymphatic vessels and DBF in different clinical stages. Distribution of the enhanced lymphatic vessels was distal to the knee in ISL stage I, involved areas below the knee joint or the whole limb in ISL stage II, and involved the whole limb in ISL stage III (X2 =44.591; P = 0.000). With the progression of edema, DBF severity increased (X2 =76.416; P = 0.000). CONCLUSION: MRL revealed the morphology and distribution of lymphatic vessels and detected abnormal inguinal lymph nodes in patients at different stages of lymphedema, which can be used as reference information for surgical treatment.

Lower extremity deformity and its risk factors in patients with solitary osteochondromas.

BACKGROUND: This study aimed to demonstrate the occurrence of lower extremity deformities and their risk factors in patients with solitary osteochondromas. METHODS: We retrospectively reviewed consecutive patients with solitary osteochondromas around the knee. The laterality (left or right), involved bone (femur or tibia), tumor type (pedunculated or sessile), and direction (medial or lateral) were examined. The whole limb length (WLL), mechanical lateral distal femoral angle (mLDFA), and medial proximal tibial angle (MPTA) were measured using teleroentgenogram. Lower limb deformity was defined as a difference of more than 5° in mLDFA or MPTA in both lower extremities or a difference in WLL of more than 1 cm. Patients were divided into two groups, with deformity and without deformity. RESULTS: Lower extremity deformities were observed in 8 of 83 patients. Significant difference in the type of osteochondroma (p = 0.004) between the groups was observed. Differences in sex, age, laterality, involved bone, direction, and distance from the physis to the osteochondroma between groups were not statistically significant. The sessile type of osteochondroma was a risk factor for lower limb deformity with an odds ratio of 24.0 according to Firth's logistic regression analysis. CONCLUSION: In our cohort with solitary osteochondroma, lower limb deformities were observed in 8 (9.6%) out of the 83 patients and these were significantly associated with sessile-type tumors. Therefore, patients with sessile-type solitary osteochondroma around the knee require careful surveillance of lower limb alignment with whole leg teleroentgenogram.

Application value of real-time shear wave elastography in the diagnosis and efficacy evaluation of venous thrombosis.

BACKGROUND: Deep vein thrombosis (DVT) of the lower limbs is a venous reflux disorder caused by abnormal coagulation of blood components, primarily characterised by swelling and pain in the lower limbs. Key risk factors include prolonged immobility due to bed rest, pregnancy, postpartum or postoperative states, traumas, malignant tumours and long-term contraceptive use. OBJECTIVE: To investigate the application of real-time shear wave elastography (SWE) in diagnosing lower-limb deep vein thrombosis (DVT). METHODS: A total of 91 patients with DVT were selected and divided into three groups: acute phase (n= 29), subacute phase (n= 30) and chronic phase (n= 32). The Young's modulus of the patients was measured using real-time SWE. The diagnostic efficacy of Young's modulus was evaluated by ROC curves. The hardness differences in Young's modulus across different parts of the same thrombus (head, body and tail) were measured using SWE. RESULTS: Before treatment, significant differences were observed in Young's modulus among patients with DVT (P< 0.001). Following anticoagulant therapy, catheter-directed thrombolysis and systemic thrombolysis, significant differences were noted in Young's modulus among patients at the same stage but receiving different treatments (acute phase: P= 0.003; subacute phase: P= 0.014; chronic phase: P= 0.004). Catheter-directed thrombolysis had greater efficacy than anticoagulant therapy. The area under the curve for SWE in staging patients was 0.917, with a sensitivity of 92.36% and specificity of 93.81%. Significant differences in Young's modulus were found between the thrombus head and thrombus body and tail but not between the thrombus body and thrombus tail. CONCLUSION: Measurement of Young's modulus using SWE can serve as an auxiliary means of evaluating staging, predicting pulmonary embolism and selecting treatment in patients with DVT.

Effects of lower limb length discrepancy on spinopelvic compensation following total hip arthroplasty in patients with developmental dysplasia of the hip.

BACKGROUND: Limited research has examined the impact of lower limb length discrepancy (LLLD) alteration on spinopelvic compensation in individuals with developmental dysplasia of the hip (DDH). This study aimed to investigate the effects of LLLD on spinopelvic compensation following total hip arthroplasty (THA) and elucidate the complex biomechanical adaptations in the spinopelvic structures. METHODS: A retrospective review of DDH patients undergoing THA from January 2014 to December 2021 categorized individuals with Crowe type I and II into the low dislocation group (LDG, n = 94) and those with Crowe type III and IV into the high dislocation group (HDG, n = 43). Demographic data, as well as preoperative, postoperative, and last follow-up imaging data, including lower limb length (LLL), sacral obliquity (SO), iliac obliquity (IO), hip obliquity (HO), Cobb angle, apical vertebral translation (AVT), and coronal decompensation (CD), were collected for analysis. RESULTS: Patients in the LDG had a significantly higher surgical age and shorter disease duration (P<0.05). In LDG, patients exhibited substantial postoperative reductions in LLLD, SO, IO, and HO (P<0.05), while Cobb Angle, AVT, and CD showed no statistically significant changes (P>0.05). The variation in LLLD correlated significantly with the variations in SO, IO, and HO (P<0.05). Postoperative outcomes in the HDG demonstrated marked decreases in LLLD, SO, IO, HO, and CD (P<0.05), with no significant change in Cobb angle and AVT (P>0.05). The variation in LLLD correlated significantly with the variations in SO, IO, HO, and CD (P<0.05). CONCLUSIONS: THA effectively reduces LLLD in patients with DDH, and the variation in LLLD correlates meaningfully with the recovery of spinopelvic compensatory mechanisms.

Lymphaticovenous anastomosis map established using lymphatic ultrasound and multi-lymphosome indocyanine green lymphography.

BACKGROUND: Although the usefulness of lymphaticovenous anasotmosis (LVA) for lymphedema has been reported, it is difficult to determine where the LVA is to be performed, especially for inexperienced surgeons. This study aimed to establish a map of the LVA site. METHOD: A total of 105 limbs from 64 patients who underwent lower limb LVA were retrospectively reviewed. Multi-lymphosome indocyanine green (ICG) lymphography (in 35 patients) and lymphatic ultrasound (in all patients) were performed preoperatively and the incision site was determined where dilated lymph vessels and appropriate veins were located in close proximity. The LVA location was identified using a post-operative photograph. Additionally, the degree of lymphatic degeneration at the LVA site was recorded based on the normal, ectasis, contraction, and sclerosis type (NECST) classification. RESULT: A total of 206 skin incisions were analyzed. Among them, 161 (75.9%) were medial and 45 (21.2%) were lateral. Among the 85 sites on the calf, 52 (61.2%) were medial and 33 (38.8%) were lateral. Among the 117 sites on the thigh, 106 (90.6%) were medial and 11 (9.4%) were lateral. As the severity of lymphedema progressed, the probability of performing LVA on the lateral calf increased. Among the 202 locations where LVA was performed on the thigh and lower leg, ectasis type was found in 164 sites (81.2%). CONCLUSION: We established an LVA map of the legs based on multi-lymphosome ICG lymphography and lymphatic ultrasound data. Using this LVA map, surgeons can easily predict the location of lymph vessels, thereby improving the success rate of LVA.

Medial cortical bone thickness of the tibial diaphysis in osteoarthritis is related to lower extremity alignment and tibial morphology.

BACKGROUND: The purpose of this study was to clarify (1) the differences in cortical bone thickness (CBT) of the tibial diaphysis between healthy and osteoarthritic knees and (2) the influences of the femorotibial angle (FTA) and inclination of the medial compartment of the proximal tibia (MCT) on tibial CBT. METHODS: The study assessed 60 subjects with varus knee osteoarthritis (OA) (22 males and 38 females; mean age, 74 ± 7 years) and 53 healthy elderly subjects (28 males and 25 females; mean age, 70 ± 6 years). Three-dimensional estimated CBT of the tibial diaphysis was automatically calculated for 2752-11,296 points using high-resolution measurements from CT. The standardized CBT was assessed in 24 regions by combining six heights and four areas. Additionally, the association between the CBT, each FTA, and MCT inclination was investigated. RESULTS: The OA group showed a thicker CBT in the medial areas than in the lateral areas of the proximal tibia, while the healthy group had a thicker lateral CBT. The medial-to-lateral ratio of the proximal tibia was significantly higher in the OA group than in the healthy group. The proximal-medial CBT correlated with FTA and MCT inclinations in the OA group. CONCLUSIONS: This study demonstrated that varus osteoarthritic knees showed a different trend of proximal-medial CBT with associations in FTA and MCT inclination from healthy knees, possibly due to medial load concentration.

Predictive value of prenatal ultrasound combined with long non-coding RNA CRNDE of women for their postpartum lower extremity deep venous thrombosis.

OBJECTIVE: Deep vein thrombosis (DVT) is a common complication in obstetrics that needs early interaction. The study examined the expression change and clinical value of long non-coding RNA (lncRNA) colorectal neoplasia differentially expressed (CRNDE) in DVT early diagnosis. METHODS: One hundred patients with DVT after delivery and 100 healthy parturients without DVT were enrolled. Serum samples were collected one day before delivery and received qRT-PCR for mRNA detection. Prenatal coagulation markers including prothrombin time (PT), activated partial prothrombin time (APTT), fibrinogen (FIB) and thrombin time (TT), D-dimer (D-D), thrombomodulin (TM), and peroxidase anti-peroxidase soluble complex (PAP) were tested. The receiver operating characteristic (ROC) curve was drawn for the diagnostic value assessment. RESULTS: LncRNA CRNDE levels increased remarkably in the serum of DVT patients compared with the healthy controls, which were negatively correlated with serum concentration of PT, APTT, and TT while positively correlated with FIB, D-D, TM, and PAP. Serum CRNDE (HR = 5.973, 95% CI = 2.990-11.933, p < .001) was independently related to the occurrence of DVT after delivery. Then, ROC curve using serum CRNDE showed a good diagnostic value for DVT with the AUC of 0.899. ROC curve of ultrasonography combined with CRNDE produced an AUC of 0.968, and both sensitivity and specificity were enhanced compared to a single indicator. CONCLUSIONS: The increase of CRNDE level was an independent risk factor for postpartum DVT. Prenatal ultrasonography combined with CRNDE can improve the predictive efficacy for DVT.

3DFRINet: A Framework for the Detection and Diagnosis of Fracture Related Infection in Low Extremities Based on 18F-FDG PET/CT 3D Images.

Fracture related infection (FRI) is one of the most devastating complications after fracture surgery in the lower extremities, which can lead to extremely high morbidity and medical costs. Therefore, early comprehensive evaluation and accurate diagnosis of patients are critical for appropriate treatment, prevention of complications, and good prognosis. 18Fluoro-deoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is one of the most commonly used medical imaging modalities for diagnosing FRI. With the development of deep learning, more neural networks have been proposed and become powerful computer-aided diagnosis tools in medical imaging. Therefore, a fully automated two-stage framework for FRI detection and diagnosis, 3DFRINet (Three Dimension FRI Network), is proposed for 18F-FDG PET/CT 3D imaging. The first stage can effectively extract and fuse the features of both modalities to accurately locate the lesion by the dual-branch design and attention module. The second stage reduces the dimensionality of the image by using the maximum intensity projection, which retains the effective features while reducing the computational effort and achieving excellent diagnostic performance. The diagnostic performance of lesions reached 91.55% accuracy, 0.9331 AUC, and 0.9250 F1 score. 3DFRINet has an advantage over six nuclear medicine experts in each classification metric. The statistical analysis shows that 3DFRINet is equivalent or superior to the primary nuclear medicine physicians and comparable to the senior nuclear medicine physicians. In conclusion, this study first proposed a method based on 18F-FDG PET/CT three-dimensional imaging for FRI location and diagnosis. This method shows superior lesion detection rate and diagnostic efficiency and therefore has good prospects for clinical application.

Modelling lower-limb peripheral arterial disease using clinically available datasets: impact of inflow boundary conditions on hemodynamic indices for restenosis prediction.

BACKGROUND AND OBJECTIVES: The integration of hemodynamic markers as risk factors in restenosis prediction models for lower-limb peripheral arteries is hindered by fragmented clinical datasets. Computed tomography (CT) scans enable vessel geometry reconstruction and can be obtained at different times than the Doppler ultrasound (DUS) images, which provide information on blood flow velocity. Computational fluid dynamics (CFD) simulations allow the computation of near-wall hemodynamic indices, whose accuracy depends on the prescribed inlet boundary condition (BC), derived from the DUS images. This study aims to: (i) investigate the impact of different DUS-derived velocity waveforms on CFD results; (ii) test whether the same vessel areas, subjected to altered hemodynamics, can be detected independently of the applied inlet BC; (iii) suggest suitable DUS images to obtain reliable CFD results. METHODS: CFD simulations were conducted on three patients treated with bypass surgery, using patient-specific DUS-derived inlet BCs recorded at either the same or different time points than the CT scan. The impact of the chosen inflow condition on bypass hemodynamics was assessed in terms of wall shear stress (WSS)-derived quantities. Patient-specific critical thresholds for the hemodynamic indices were applied to identify critical luminal areas and compare the results with a reference obtained with a DUS image acquired in close temporal proximity to the CT scan. RESULTS: The main findings indicate that: (i) DUS-derived inlet velocity waveforms acquired at different time points than the CT scan led to statistically significantly different CFD results (p<0.001); (ii) the same luminal surface areas, exposed to low time-averaged WSS, could be identified independently of the applied inlet BCs; (iii) similar outcomes were observed for the other hemodynamic indices if the prescribed inlet velocity waveform had the same shape and comparable systolic acceleration time to the one recorded in close temporal proximity to the CT scan. CONCLUSIONS: Despite a lack of standardised data collection for diseased lower-limb peripheral arteries, an accurate estimation of luminal areas subjected to altered near-wall hemodynamics is possible independently of the applied inlet BC. This holds if the applied inlet waveform shares some characteristics - derivable from the DUS report - as one matching the acquisition time of the CT scan.

Ultrasound elastography predicts anticoagulation in lower extremity deep vein thrombosis.

OBJECTIVE: To investigate predictors of anticoagulation efficacy in deep venous thrombosis (DVT) by ultrasound elastography (UE). METHODS: The basic clinical, laboratory and ultrasound treatment data of fifty-eight patients with DVT were collected and analyzed. Then the results of ultrasound after 3-month anticoagulation treatment were compared among different groups. Multiple logistic regression analysis was used to identify independent risk factors that affected anticoagulation efficacy. The predictive efficacy of each independent risk factor was accessed by drawing operating characteristic (ROC) curves. RESULTS: According to the regression analysis, the elastic modulus (OR = 0.631, P = 0.001) and strain rate ratio (OR = 0.332, P = 0.006) were identified as independent risk factors for the effectiveness of anticoagulation therapy in patients with DVT. According to the ROC curves, elastic modulus and strain rate ratio could predict effective anticoagulation therapy for DVT, and the optimal threshold values were 22.10 kPa and 1.80 respectively. The corresponding AUC values were 0.879 and 0.854, with a sensitivity of 71.4% and 59.5%, a specificity of 93.7%, and a Youden index of 65.1% and 62.7%, respectively. CONCLUSIONS: The elastic modulus (≤22.10 kPa) or strain rate ratio (≤1.80) of the thrombus were independent predictors for the effectiveness of anticoagulation therapy.

Characteristic Single Photon Emission Computed Tomography-Computed Tomography Findings in Lower Extremity Lymphedema: Comparison to Indocyanine Green Lymphography.

Introduction: Evaluation of lymph circulation is significant in lower extremity lymphedema (LEL) management. Single-photon emission computed tomography-computed tomography (SPECT-CT) has been introduced for lymphedema evaluation, but its characteristic findings are yet fully clarified. The purpose of this study was to reveal typical SPECT-CT findings in secondary LEL by contrasting with indocyanine green (ICG) lymphography findings. Methods: This is a single-center retrospective case-control study. Medical charts of cancer survivors who underwent SPECT-CT and ICG lymphography for secondary LEL were reviewed. Lymphedematous limbs were defined as ICG lymphography stage I-V and non-lymphedematous limbs were defined as ICG lymphography stage 0. Characteristic SPECT-CT findings were identified in early phase and delay phase, and prevalence of the findings was compared between lymphedematous limbs and non-lymphedematous limbs. Results: Thirty-four limbs of 17 patients were included in this study; 6 (17.6%) non-lymphedematous limbs and 28 (82.4%) lymphedematous limbs. Four characteristic SPECT-CT findings were identified; delayed enhancement of the main lower leg lymphatic pathway (DML), few delayed inguinal lymph nodes enhancement (FDN), early phase discontinuous enhancement of the main lymphatic pathway (EDM), and nonenhancement of the deep lymphatic pathways in early phase (NDE). Between lymphedematous and non-lymphedematous limbs, there were statistically significant differences in FDN (64.3% vs. 0%, p = 0.004) and EDM (67.9% vs. 0%, p = 0.002). Conclusions: FDN and EDM are characteristic SPECT-CT findings in secondary LEL.

De Novo Metastatic Prostate Cancer Presenting With Atypical Lower-Limb Skeletal Metastases Detected on 68 Ga-PSMA PET/CT.

ABSTRACT: Metastatic prostate cancer to the appendicular skeleton is rare. We present an 86-year-old man with undiagnosed prostate cancer presenting with unilateral foot pain. CT and MRI demonstrated a sclerotic midfoot suggestive of an infiltrative process. In view of an elevated PSA, metastatic disease was suspected, and bone scan confirmed osteoblastically active pelvic and lower-limb skeletal lesions. Subsequent prostate biopsy confirmed prostate adenocarcinoma. Staging 68 Ga-PSMA PET/CT demonstrated PSMA-avid intraprostatic malignancy with pelvic and right lower-limb skeletal metastases. This is an unusual case of de novo 68 Ga-PSMA-avid metastatic prostate cancer with atypical lower-limb skeletal metastases presenting with foot pain.

Pitfalls of ultrasound for deep vein thrombosis of the lower extremities.

Venous ultrasound is the primary, widely accepted diagnostic tool to assess deep vein thrombosis (DVT) in the lower extremities. However, other focal lesions in the lower extremities can be identified on ultrasound. The sonographic appearance of these abnormalities may overlap the thrombosis, which included vascular tumors, Baker's cyst, hematoma, cancer thrombosis, and peripheral nerve tumors. This essay derives from cases diagnosed in our centers and published literature, with images available for illustrations, which may help to improve the clinical management of these findings.

Automatic measurement of lower limb alignment in portable devices based on deep learning for knee osteoarthritis.

BACKGROUND: For knee osteoarthritis patients, analyzing alignment of lower limbs is essential for therapy, which is currently measured from standing long-leg radiographs of anteroposterior X-ray (LLR) manually. To address the time wasting, poor reproducibility and inconvenience of use caused by existing methods, we present an automated measurement model in portable devices for assessing knee alignment from LLRs. METHOD: We created a model and trained it with 837 conforming LLRs, and tested it using 204 LLRs without duplicates in a portable device. Both manual and model measurements were conducted independently, then we recorded knee alignment parameters such as Hip knee ankle angle (HKA), Joint line convergence angle (JCLA), Anatomical mechanical angle (AMA), mechanical Lateral distal femoral angle (mLDFA), mechanical Medial proximal tibial angle (mMPTA), and the time required. We evaluated the model's performance compared with manual results in various metrics. RESULT: In both the validation and test sets, the average mean radial errors were 2.778 and 2.447 (P<0.05). The test results for native knee joints showed that 92.22%, 79.38%, 87.94%, 79.82%, and 80.16% of the joints reached angle deviation<1° for HKA, JCLA, AMA, mLDFA, and mMPTA. Additionally, for joints with prostheses, 90.14%, 93.66%, 86.62%, 83.80%, and 85.92% of the joints reached that. The Chi-square test did not reveal any significant differences between the manual and model measurements in subgroups (P>0.05). Furthermore, the Bland-Altman 95% limits of agreement were less than ± 2° for HKA, JCLA, AMA, and mLDFA, and slightly more than ± 2 degrees for mMPTA. CONCLUSION: The automatic measurement tool can assess the alignment of lower limbs in portable devices for knee osteoarthritis patients. The results are reliable, reproducible, and time-saving.

Discrepancies in Sagittal Alignment of the Lower Extremity Among Different Brands of Robotic Total Knee Arthroplasty Systems.

BACKGROUND: There is an increasing number of different brands of robotic total knee arthroplasty (TKA) systems. Most robotic TKA systems share the same coronal alignment, while the definitions of sagittal alignment vary. The purpose of this study was to investigate whether these discrepancies impact the sagittal alignment of the lower extremity. METHODS: A total of 72 lower extremity computed tomography scans were included in our study, and 3-dimensional models were obtained using software. A total of 7 brands of robotic TKA systems were included in the study. The lower extremity axes were defined based on the surgical guide for each implant. We also set the intramedullary axis as a reference to evaluate the discrepancies in sagittal alignment of each brand of robotic system. RESULTS: On the femoral side, the axis definition was the same for all 7 robotic TKA systems. The robotic TKA axes showed a 2.41° (1.58°, 3.38°) deviation from the intramedullary axis. On the tibial side, the 7 robots had different axis definitions. The tibial mechanical axis of 6 of the TKA systems was more flexed than that of the intramedullary axis, which means the posterior tibial slope was decreased while the tibial mechanical axis of the remaining system was more extended. CONCLUSIONS: The sagittal alignment of the lower extremity for 7 different brands of robotic TKA systems differed from each other and all deviated from the intramedullary axis. Surgeons should be aware of this discrepancy when using different brands of robotic TKA systems to avoid unexpected sagittal alignment and corresponding adverse clinical outcomes. LEVEL OF EVIDENCE: Level IV, Therapeutic Study.

The influence of the weight-bearing state on three-dimensional (3D) planning in lower extremity realignment - analysis of novel vs. state-of-the-art planning approaches.

BACKGROUND: The use of 3D planning to guide corrective osteotomies of the lower extremity is increasing in clinical practice. The use of computer-tomography (CT) data acquired in supine position neglects the weight-bearing (WB) state and the gold standard in 3D planning involves the manual adaption of the surgical plan after considering the WB state in long-leg radiographs (LLR). However, this process is subjective and dependent on the surgeons experience. A more standardized and automated method could reduce variability and decrease costs. PURPOSE: The aim of the study was (1) to compare three different three-dimensional (3D) planning modalities for medial open-wedge high tibial osteotomy (MOWHTO) and (2) to describe the current practice of adapting NWB CT data after considering the WB state in LLR. The purpose of this study is to validate a new, standardized approach to include the WB state into the 3D planning and to compare this method against the current gold standard of 3D planning. Our hypothesis is that the correction is comparable to the gold standard, but shows less variability due compared to the more subjective hybrid approach. METHODS: Three surgical planning modalities were retrospectively analyzed in 43 legs scheduled for MOWHTO between 2015 and 2019. The planning modalities included: (1) 3D hybrid (3D non-weight-bearing (NWB) CT models after manual adaption of the opening angle considering the WB state in LLR, (2) 3D NWB (3D NWB CT models) and (3) 3D WB (2D/3D registration of 3D NWB CT models onto LLR to simulate the WB state). The pre- and postoperative hip-knee-ankle angle (HKA) and the planned opening angle (°) were assessed and differences among modalities reported. The relationship between the reported differences and BMI, preoperative HKA (LLR), medial meniscus extrusion, Outerbridge osteoarthritis grade and joint line convergence angle (JLCA) was analyzed. RESULTS: The mean (std) planned opening angle of 3D hybrid did not differ between 3D hybrid and 3D WB (0.4 ± 2.1°) (n.s.) but was higher in 3D hybrid compared to 3D NWB (1.1° ± 1.1°) (p = 0.039). 3D WB demonstrated increased preoperative varus deformity compared to 3D NWB: 6.7 ± 3.8° vs. 5.6 ± 2.7° (p = 0.029). Patients with an increased varus deformity in 3D WB compared to 3D NWB (> 2 °) demonstrated more extensive varus alignment in LLR (p = 0.009) and a higher JLCA (p = 0.013). CONCLUSION: Small intermodal differences between the current practice of the reported 3D hybrid planning modality and a 3D WB approach using a 2D/3D registration algorithm were reported. In contrast, neglecting the WB state underestimates preoperative varus deformity and results in a smaller planned opening angle. This leads to potential under correction in MOWHTO, especially in patients with extensive varus deformities or JLCA. CLINICAL RELEVANCE: Incorporating the WB state in 3D planning modalities has the potential to increase accuracy and lead to a more consistent and reliable planning in MOWHTO. The inclusion of the WB state in automatized surgical planning algorithms has the potential to reduce costs and time in the future.

Magnetic resonance lymphangiography: Establishing normal.

BACKGROUND: Despite an increased interest in visualizing the lymphatic vessels with magnetic resonance lymphangiography (MRL), little literature is available describing their appearance in nonlymphedematous individuals. To determine lymphatic abnormalities, an understanding of how healthy lymphatic vessels appear and behave needs to be established. Therefore, in this study, MRL of individuals without a history of lymphatic disease was performed. METHODS: A total of 25 individuals (15 women) underwent MRL of their lower limbs using a 3.0 T Philips magnetic resonance imaging scanner (Philips Medical Systems). The first nine participants were recruited to establish the concentration of gadolinium-based contrast agent (GBCA) to administer, with the remainder imaged before and after interdigital forefoot GBCA injections at the optimized dose. Outcomes, including lymphatic vessel diameter, tortuosity, and frequency of drainage via particular drainage routes, were recorded. RESULTS: Healthy lymphatic vessels following the anteromedial pathway were routinely observed in post-contrast T1-weighted images (average tortuosity, 1.09 ± 0.03), with an average of 2.16 ± 0.93 lymphatic vessels with a diameter of 2.47 ± 0.50 mm crossing the anterior ankle. In six limbs, vessels following the anterolateral pathways were observed. No vessels traversing the posterior of the legs were seen. In a subset of 10 vessels, the lymphatic signal, measured at the ankle, peaked 29 minutes, 50 seconds ± 9 minutes, 29 seconds after GBCA administration. No lymphatic vessels were observed in T2-weighted images. CONCLUSIONS: Contrast-enhanced MRL reliably depicts the lymphatic vessels in the legs of healthy controls. Following interdigital contrast injection, anteromedial drainage appears dominant. Quantitative measures related to lymphatic vessel size, tortuosity, and drainage rate are readily obtainable and could be beneficial for detecting even subtle lymphatic impairment.