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Rationale and Objectives: Up to now, the diagnosis of tendinopathies is based on conventional B-mode-ultrasound (B-US), Power Doppler-ultrasound (PD-US), and magnetic resonance imaging. In the past decade, Shear Wave Elastography (SWE) has been introduced in tendon imaging, for example in athletes or patients suffering from tendinopathy. SWE allows real-time quantification of tissue stiffness, and, by this, the assessment of the mechanical properties of a tendon and its changes during acute disease and tendon healing. So far there are no ultrasound-based studies that have evaluated postoperative tendon changes, anatomical and mechanical properties and tendon healing of the patellar, and quadriceps tendon following Total Knee Arthroplasty (TKA). The purpose of this prospective study was two-fold: first to analyze morphologic, vascular, and mechanical properties of patellar and quadriceps tendons in patients following TKA; and, second to evaluate possible changes thereof and their visibility in the course of time., Materials and Methods: Observational cross-sectional, IRB-approved study in 63 postoperative patients with a total of 76 total knee arthroplasties (50 unilateral, 13 bilateral) and 50 nonoperated knees for comparison, resulting in 152 postoperative patellar- and quadriceps and 100 nonoperated patellar- and quadriceps-tendons for comparative analysis. For further examination, we divided the 63 patients into two groups according to the duration since surgery (group A < 24 months; group B > 24 months). All patients completed a standardized questionnaire, furthermore the Knee Society score and the Knee Society function score. The amount of experienced pain was assessed using the ordinal numeric rating scale and the presence of anterior knee pain was examined. Subsequently every participant underwent a standardized multimodal ultrasound protocol consisting of B-US, PD-US, and SWE of the left and right patellar and quadriceps tendons., Results: Using the different US-modalities, operated patellar, and quadriceps tendons (n = 152) were significantly more frequent classified as pathological (B-US) (p < 0.001), the mean Ohberg score was significantly higher (PD-US) (p < 0.001), and the tendons were significantly softer (SWE) than their nonoperated counterparts (n = 100). Mean SWE-value of postoperative patellar tendons was 45.66 ± 14.84 kPa versus 60.08 ± 19.13 kPa in nonoperated knees (p < 0.001). Mean SWE-value of postoperative quadriceps tendons was 35.73 ± 15.66 kPa versus 52.69 ± 16.20 kPa in nonoperated knees (p < 0.001). Comparing the two postoperative groups (group A and B), we recognized a significant decrease of pathologically classified patellar and quadriceps tendons (B-US and PD-US) in group B. The early postoperatively reduced SWE values slightly increased during the course of time., Conclusion: After TKA, patellar, and quadriceps tendons show significant measurable alterations in B-US, PD-US, and SWE. Especially a significant decrease of tendon stiffness in operated knees, as assessed by SWE, might be a surrogate marker for changed mechanical properties. These alterations improve, the longer ago the surgery was. The quantitative information obtained by SWE could be of particular interest in follow-up and therapy monitoring after TKA. Knowledge about tendon stiffness and it's varieties in different population groups (e.g. athletes, elderly, postoperative patients) is crucial to sonographically rate a tendon as "healthy" or "diseased.", (Copyright © 2019 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Rationale and Objectives: The current imaging standard for diagnosing plantar fasciitis is B-Mode ultrasound (B-US). The aim of this study was to determine the diagnostic potential of Shear Wave Elastography (SWE) and the correlation of clinical scores to elastographic parameters., Materials and Methods: Diagnostic case-control study with n = 82 plantar fascia (PF). PF were divided into three subgroups: (1) symptomatic PF (n = 39); (2) control group of unilateral asymptomatic PF (n = 23); (3) bilateral asymptomatic PF (n = 20). Reference standard for positive findings in B-US was a PF thickness greater than 4 mm. For SWE tissue elasticity (Young's modulus kPa; shear wave speed m/s) was measured at Location 1: directly at the calcaneus; Location 2: +1 cm distal of the calcaneus and Location 3: central part of the calcaneus. Sensitivity, specificity, and diagnostic accuracy as well as correlation to American Orthopaedic Foot and Ankle Score (AOFAS) and Food Functional Index (FFI) were determined., Results: Symptomatic PF are thicker (4.2 mm, n = 39) than asymptomatic (3.0 mm, n = 43) (p < 0.001). Thickness of the PF (n = 82) correlated poorly to clinical scores (p = 0.001): FFI-pain (r = 0.349); FFI-function (r = 0.381); AOFAS (r = -0.387). Cut-off point for positive SWE finding was 51.5 kPa (4.14 m/s). Symptomatic PF (31.9 kPa, 3.26 m/s, n = 39) differ significantly from asymptomatic PF (93.3 kPa, 5.58 m/s, n = 43) with significant differences at L1 between all groups (p < 0.001). Correlation between Young's modulus (n = 82) and clinical scores was strong (p < 0.001): FFI-pain (r = -0.595); FFI-function (r = -0.567); AOFAS (r = 0.623,). B-US: sensitivity (61%), specificity (95%); SWE sensitivity (85%), specificity (83%). The combination of SWE and B-US increases the sensitivity (100%) with a diagnostic accuracy of 90%., Conclusion: Based on our results, we could show that SWE can improve the diagnostic accuracy in patients with plantar fasciitis compared to B-US., Level of Evidence: II., (Copyright © 2019. Published by Elsevier Inc.)

Rationale and Objectives: It has been shown that Shear Wave Elastography (SWE) is a useful tool to evaluate tendon stiffness, e.g. in diagnosing tendinopathies, as diseased or injured tendons are intra-individually softer than healthy ones. But reference values between different population groups are still missing. The purpose of this prospective clinical study was two-fold: First, to comparatively analyse Achilles tendon stiffness between asymptomatic semiprofessional athletes and an asymptomatic nonathletic control group. Second, to evaluate specificity, with which SWE is able to predict absence of clinical symptoms in asymptomatic individuals, compared to B-mode-Ultrasound (B-US) and Power Doppler-Ultrasound (PD-US)., Materials and Methods: Prospective clinical study in 68 asymptomatic healthy participants, 33 (48.5%) of them semiprofessional athletes with at least five training units of running per week and 35 (51.5 %) normal nonathletic persons, asymptomatic respectively. A consecutive of 136 Achilles tendons underwent standardized multi-modal ultrasound, consisting of B-US, PD-US, and SWE (Aixplorer, Supersonic). Pathologic structural changes at B-US, increased Doppler signal PD-US and quantitative ROI-based-analysis of tendon elasticity in kilopascal (kPa) were performed in all participants. Tendon stiffness was compared intra-individually between right and left side in each participant. SWE values between athletes and nonathletes were compared by using student's t test (p < 0.05). To evaluate the ability of different sonographic modalities in predicting "absence of clinical symptoms", specificities of B-US, PD-US, and SWE were calculated and compared among each other., Results: Mean SWE-value for Achilles tendon was 183.8 kPa (± 98 kPa) in athletes and 103.6 kPa (± 30.5 kPa) in the nonathletic control group. The difference between athletes and non-athletes was statistically significant (p < 0.001). No significant differences were found intra-individually between right and left side: athlete mean: right: 187.2 kPa (SD ± 45.2 kPa)/left: 180.4 kPa (SD 39.7 kPa); nonathlete mean: right: 105.4 kPa (SD 34.9 kPa)/left: 101.8 kPa (SD 28.9 kPa). Specificity with which asymptomatic tendons were rated as "inconspicuous" was 60.6% for B-US, 93.9% for PD-US and 96.3% for SWE., Conclusion: Healthy athletes exhibit significantly higher SWE-values in Achilles tendons than healthy nonathletic participants, which means that they have significantly stiffer tendons, possibly caused by repeated training. SWE is able to measure and display these effects. These interindividual differences should be taken into consideration, especially when rating a tendon as "healthy" or "diseased", because a "softer" tendon does not necessarily mean to be affected., (Copyright © 2019 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Rationale and Objectives: We aimed to investigate the diagnostic accuracy with which shear wave elastography (SWE) can be used to monitor response to treatment of tendinopathies, and to compare it to conventional ultrasound (US)-imaging methods (B-mode US (B-US) and power Doppler US (PD-US))., Materials and Methods: A prospective Institutional Review Board-approved longitudinal study on 35 patients with 47 symptomatic tendons (17 Achilles-, 15 patellar-, and 15 humeral-epicondylar) who underwent standardized multimodal US and standardized clinical assessment before and after 6 months of treatment (tailored stretching exercise, sport break, and local Polidocanol) was carried out. All US studies were performed by radiologists blinded to the clinical symptoms on both tendon sides to avoid biased interpretations, by B-US, PD-US, and SWE, conducted in the same order, using a high-resolution linear 15 MHz probe (Aixplorer). Orthopedic surgeons who were in turn blinded to US imaging results used established orthopedic scores (Victorian Institute of Sports Assessment questionnaire for Achilles, Victorian Institute of Sports Assessment questionnaire for patellar tendons, and Disability Arm Shoulder Hand scoring system) to rate presence, degree, and possible resolution of symptoms. We analyzed the diagnostic accuracy with which the different US imaging methods were able to detect symptomatic tendons at baseline as well as treatment effects, with orthopedic scores serving as reference standard., Results: B-US, PD-US, and SWE detected symptomatic tendons with a sensitivity of 66% (31 of 47), 72% (34 of 47), and 87.5% (41 of 47), respectively. Positive predictive value was 0.67 for B-US, 0.87 for PD-US, and 1 for SWE. After treatment, clinical scores improved in 68% (32 of 47) of tendons. Treatment effects were observable by B-US, PD-US, and SWE with a sensitivity of 3.1% (1 of 32), 28.1% (9 of 32), and 81.3% (26 of 32), respectively. B-US was false-positive in 68.8% (20 of 32), PD-US in 46.9% (15 of 32), and SWE in 12.5% (4 of 32) (SWE). Clinical scores and B-US, PD-US, and SWE findings correlated poorly (r = 0.24), moderately (r = 0.59), and strongly (r = 0.80)., Conclusion: Unlike B-US or PD-US, SWE is able to depict processes associated with tendon healing and may be a useful tool to monitor treatment effects., (Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Rationale and Objectives: Shear wave elastography (SWE) has been shown to be a powerful tool to estimate tissue stiffness. The aim of this study was to compare the diagnostic accuracy of SWE to that of standard ultrasound (US) (combined use of B-mode US and power Doppler [PD] US) for diagnosing tendinopathies., Materials and Methods: This is a prospective institutional review board-approved study on 112 participants (mean age 42 ± 13.4 years) with chronic (>6 months) tendon pain in Achilles, patellar, or epicondylar tendons. Participants were systematically examined with US, PD, and SWE using a high-resolution linear 15 MHz probe (SuperSonic Imagine). A semiquantitative analysis of SWE color charts and a quantitative region of interest-based analysis of tendon elasticity were performed. SWE values of symptomatic and healthy tendons were compared by using Student t test. Clinical symptom scores served as the standard of reference. US findings were compared to clinical symptom scores by using Spearman correlation., Results: At semiquantitative analysis of SWE color charts, symptomatic tendons were rated as "soft" in 80/140 (57.1%), as "intermediate" in 54/140 (38.6%), and as "rigid" in 6/140 (4.3%). Healthy tendons were rated as "soft" in 8/84 (10%), as "intermediate" in 31/84 (37%), and as "rigid" in 45/84 (53%). At quantitative analysis, symptomatic tendons exhibited significantly lower mean SWE values (60.3 kPa/4.48 m/s; range 15.3-201.4 kPa/2.26-14.18 m/s) than healthy tendons (185 kPa/7.85 m/s; range 56-265 kPa/4.32-9.23 m/s) (P = 0.0004). SWE values correlated closely with patients' clinical symptoms obtained by clinical scores (r = 0.81). Overall sensitivity of conventional US and PD in detecting tendinopathies could be enhanced from 67.1% (94/140) to 94.3% (132/140) when combined with SWE., Conclusions: SWE is a simple way to estimate tissue stiffness and, by reduced tissue rigidity, to identify tendon pathology. SWE significantly increases the diagnostic accuracy of tendon sonography and may prove to be a sensitive tool to early detect or monitor tendinopathy., (Copyright © 2016 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)