Is Sonographic Assessment of Intratendinous Blood Flow in Achilles Tendinopathy Patients Reliable?: Consistency of Doppler Ultrasound Modes and Intra- and Inter-observer Reliability

Chronologic Changes in the Elastic Modulus of a Healing Achilles Tendon Rupture Measured Using Shear Wave Elastography

BACKGROUND

Shear wave elastography (SWE) has been used to examine the elasticity of a ruptured Achilles tendon; however, the healing process of a ruptured tendon has not been studied yet. This study aimed to detail the change in mechanical properties of a healing Achilles tendon rupture managed conservatively or surgically using SWE.

METHODS

Using a prospective cohort study design, we evaluated the patients treated conservatively (conservative group) and surgically (surgical group) with the "gift-box" technique for an isolated index acute Achilles tendon rupture during their healing process. SWE measurements were taken of both the injured and uninjured sides every 4 weeks up to 24, 36, and 48 weeks after treatment. Additionally, tendon thickness and power Doppler (PD) grade were measured at the same time points as SWE measurements. The American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot rating system score and Achilles tendon Total Rupture Score (ATRS) were compared at 24 and 48 weeks.

RESULTS

The ruptured Achilles tendon obtained an SWE value comparable with the unruptured side at 12 weeks in the conservative group and at 4 weeks with surgical group. The surgical group had significantly higher SWE values up to 24 weeks compared with the conservative group. Additionally, this group had a significantly larger increase in tendon thickness in nearly all periods. Both treatment groups were comparable regarding the PD grade, AOFAS score, and ATRS.

CONCLUSION

SWE is a convenient noninvasive method to determine the progress of the healing process after tendon injury. Our analysis using SWE has revealed the detailed chronologic changes in SWE values and related mechanical properties of a healing Achilles tendon rupture, which can be used for devising appropriate rehabilitation protocols.

LEVEL OF EVIDENCE

Level II, prospective cohort study.

Reliability of a New Semi-automatic Image Analysis Method for Evaluating the Doppler Signal and Intratendinous Vascular Resistance in Patellar Tendinopathy

The aim of this study was to determine the intra- and inter-rater reliability of a new semi-automatic image analysis method for quantification of the shape of the Doppler signal and the intratendinous vascular resistance in patellar tendinopathy. Thirty athletes (27.4 y, standard deviation = 8.57 y) with patellar intratendinous vascularity were included in a cross-sectional study (42 tendons analyzed). The intratendinous blood flow was assessed with power Doppler and ImageJ (Version 1.50b, National Institutes of Health, Bethesda, MD, USA) quantification software over a manually selected region of interest. Two blinded observers performed the analysis of the Doppler signal (vascular resistance) and shape descriptors (number of signals, pixel intensity, area, perimeter, major diameter, minor diameter, circularity and solidity). The intraclass correlation coefficient (ICC) was calculated, and the Bland-Altman mean of differences (MoD) and 95% limits of agreement (LoA) were determined. Also, small real differences (SRDs) and the standard error of measurement (SEM) were calculated. Intra-rater reliability was at a maximum for area (ICC = 0.999, 95% confidence interval [CI] = 0.998-0.999) and at a minimum for solidity (ICC = 0.782, 95% CI: 0.682-0.853). The MoD and 95% LoA were very low, and the relative SRD and SEM were below 5.3% and 2%, respectively. The inter-rater reliability was the maximum for area (ICC = 0.993, 95% CI = 0.989-0.996) and the minimum for circularity (ICC = 0.73; 95% CI=0.611-0.817). The MoD and 95% LoA were low, with the SRD and SEM below 6% and 2.2%. The proposed quantitative method for studying the intratendinous Doppler signal in the patellar tendon is reliable and reproducible.

Intraindividual Doppler Flow Response to Exercise Differs Between Symptomatic and Asymptomatic Achilles Tendons

Objective

This study investigated intraindividual differences of intratendinous blood flow (IBF) in response to running exercise in participants with Achilles tendinopathy.

Design

This is a cross-sectional study.

Setting

The study was conducted at the University Outpatient Clinic.

Participants

Sonographic detectable intratendinous blood flow was examined in symptomatic and contralateral asymptomatic Achilles tendons of 19 participants (42 ± 13 years, 178 ± 10 cm, 76 ± 12 kg, VISA-A 75 ± 16) with clinically diagnosed unilateral Achilles tendinopathy and sonographic evident tendinosis.

Intervention

IBF was assessed using Doppler ultrasound “Advanced Dynamic Flow” before (Upre) and 5, 30, 60, and 120 min (U5–U120) after a standardized submaximal constant load run.

Main Outcome Measure

IBF was quantified by counting the number (n) of vessels in each tendon.

Results

At Upre, IBF was higher in symptomatic compared with asymptomatic tendons [mean 6.3 (95% CI: 2.8–9.9) and 1.7 (0.4–2.9), p < 0.01]. Overall, 63% of symptomatic and 47% of asymptomatic Achilles tendons responded to exercise, whereas 16 and 11% showed persisting IBF and 21 and 42% remained avascular throughout the investigation. At U5, IBF increased in both symptomatic and asymptomatic tendons [difference to baseline: 2.4 (0.3–4.5) and 0.9 (0.5–1.4), p = 0.05]. At U30 to U120, IBF was still increased in symptomatic but not in asymptomatic tendons [mean difference to baseline: 1.9 (0.8–2.9) and 0.1 (-0.9 to 1.2), p < 0.01].

Conclusion

Irrespective of pathology, 47–63% of Achilles tendons responded to exercise with an immediate acute physiological IBF increase by an average of one to two vessels (“responders”). A higher amount of baseline IBF (approximately five vessels) and a prolonged exercise-induced IBF response found in symptomatic ATs indicate a pain-associated altered intratendinous “neovascularization.”

Multimodal Ultrasound Versus MRI for the Diagnosis and Monitoring of Achilles Tendinopathy: A Prospective Longitudinal Study

Background:

The diagnosis and monitoring of Achilles tendinopathy with imaging are challenging. There is a lack of studies comparing the diagnostic accuracy of magnetic resonance imaging (MRI), brightness mode ultrasound (B-mode), and power Doppler ultrasound with recent technologies such as ultrasound tissue characterization (UTC) and shear wave elastography (SWE).

Purpose:

To assess whether SWE and UTC, which offer quantitative values, show a superior diagnostic accuracy and capacity to detect structural improvement in Achilles tendinopathy compared with MRI, B-mode, or power Doppler.

Study Design:

Cohort study (diagnosis); Level of evidence, 2.

Methods:

Patients with insertional (n = 28) and midportion (n = 38) Achilles tendinopathy were evaluated at baseline and 6-month follow-up using MRI, B-mode, power Doppler, SWE, and UTC. Asymptomatic controls (n = 37) were evaluated at T₀. Diagnostic accuracy was analyzed based on a quantitative receiver operating characteristic (ROC) analysis with quantitative cutoff values (anteroposterior diameter, Öhberg score, UTC echo type, Young modulus) and by semiquantitative Likert scale–based assessment of experienced physicians.

Results:

For diagnosing insertional Achilles tendinopathy, semiquantitative MRI and power Doppler were most favorable (diagnostic accuracy, 95%), while the cross-sectional area of MRI revealed 89% accuracy in the ROC analyses (area under the curve [AUC], 0.911; P < .001). For diagnosing midportion Achilles tendinopathy, semiquantitative MRI and B-mode were most favorable (diagnostic accuracy, 87%), while UTC echo types 3 and 4 revealed 86% and 87% accuracy, respectively, in the ROC analyses (AUC, 0.911 and 0.941, respectively; P < .001). However, for quantitative and semiquantitative evaluation of diagnostic accuracy in both insertional and midportion Achilles tendinopathy, there was no significant difference in favor of one imaging modality over the others. Compared with baseline, only SWE showed a significant change at the 6-month follow-up (P = .003-.035), but there were only fair to poor monitoring accuracies of 71% (insertion) and 60% (midportion). However, compared with the other modalities, the monitoring accuracy of SWE was significantly higher (P = .002-.039).

Conclusion:

There was no statistically significant difference in favor of one imaging modality over the others, but MRI revealed the highest overall diagnostic accuracy for the diagnosis of both insertional and midportion Achilles tendinopathy.

Doppler Flow Response Following Running Exercise Differs Between Healthy and Tendinopathic Achilles Tendons

Background

The relationship between exercise-induced intratendinous blood flow (IBF) and tendon pathology or training exposure is unclear.

Objective

This study investigates the acute effect of running exercise on sonographic detectable IBF in healthy and tendinopathic Achilles tendons (ATs) of runners and recreational participants.

Methods

48 participants (43 ± 13 years, 176 ± 9 cm, 75 ± 11 kg) performed a standardized submaximal 30-min constant load treadmill run with Doppler ultrasound “Advanced dynamic flow” examinations before (U_pre) and 5, 30, 60, and 120 min (U₅-U₁₂₀) afterward. Included were runners (>30 km/week) and recreational participants (<10 km/week) with healthy (H_run, n = 10; H_rec, n = 15) or tendinopathic (T_run, n = 13; T_rec, n = 10) ATs. IBF was assessed by counting number [n] of intratendinous vessels. IBF data are presented descriptively (%, median [minimum to maximum range] for baseline-IBF and IBF-difference post-exercise). Statistical differences for group and time point IBF and IBF changes were analyzed with Friedman and Kruskal-Wallis ANOVA (α = 0.05).

Results

At baseline, IBF was detected in 40% (3 [1–6]) of H_run, in 53% (4 [1–5]) of H_rec, in 85% (3 [1–25]) of T_run, and 70% (10 [2–30]) of T_rec. At U₅ IBF responded to exercise in 30% (3 [−1–9]) of H_run, in 53% (4 [−2–6]) of H_rec, in 70% (4 [−10–10]) of T_run, and in 80% (5 [1–10]) of T_rec. While IBF in 80% of healthy responding ATs returned to baseline at U₃₀, IBF remained elevated until U₁₂₀ in 60% of tendinopathic ATs. Within groups, IBF changes from U_pre-U₁₂₀ were significant for H_rec (p < 0.01), T_run (p = 0.05), and T_rec (p < 0.01). Between groups, IBF changes in consecutive examinations were not significantly different (p > 0.05) but IBF-level was significantly higher at all measurement time points in tendinopathic versus healthy ATs (p < 0.05).

Conclusion

Irrespective of training status and tendon pathology, running leads to an immediate increase of IBF in responding tendons. This increase occurs shortly in healthy and prolonged in tendinopathic ATs. Training exposure does not alter IBF occurrence, but IBF level is elevated in tendon pathology. While an immediate exercise-induced IBF increase is a physiological response, prolonged IBF is considered a pathological finding associated with Achilles tendinopathy.

Instructing Ultrasound-guided Examination Techniques Using a Social Media Smartphone App

Social media applications on smartphones allow for new avenues of instruction in sports medicine and exercise sciences. This study tested the feasibility of instructing health care personnel through videos of ultrasound vascular measurements distributed by a social media messenger application. After two training sessions with an ultrasound device, voluntary physicians (n=10) and nurses (n=10) received a video for the performance of an ultrasound-guided determination of intima-media-thickness and diameter of the femoral arteries via a social media messenger application. All participants examined the same healthy human subject. There was no significant difference between the groups regarding overall time of performance, measurements of the femoral arteries, or a specifically designed "assessment of mobile imparted arterial ultrasound determination" score. The physicians group achieved significantly higher scores in the established "objective structured assessment of ultrasound skills" score (p=0.019). Approval of the setting was high in both groups. Transmission of videos via social media applications can be used for instructions on the performance of ultrasound-guided vascular examinations in sports medicine, even if investigators' performances differ depending on their grade of ultrasound experience. In the future, the chosen approach should be tested in practical scientific examination settings.

Ultrasound Doppler Flow in Patients With Chronic Midportion Achilles Tendinopathy: Is Surface Area Quantification a Reliable Method?

OBJECTIVES

Ultrasound assessments of patients with chronic midportion Achilles tendinopathy include determining the degree of neovascularization using Doppler flow. A frequently used measure to quantify neovascularization is the modified Öhberg score. It is unknown whether the semiquantitative modified Öhberg score (0-4+) has higher reliability than a quantified measure of Doppler flow (0-100%). The purpose of this cross-sectional study was to evaluate the interobserver reliability of the modified Öhberg score and a surface area quantification (SAQ) method for Doppler flow in patients with chronic midportion Achilles tendinopathy.

METHODS

Two observers examined the degree of Doppler flow independently using SAQ and the modified Öhberg score during a single consultation. The intraclass correlation coefficient, standard error of measurement, and minimal detectable difference were determined to evaluate the reliability and measurement properties of the SAQ method and the modified Öhberg score.

RESULTS

In total, 28 consecutive patients with chronic midportion Achilles tendinopathy participated. The intraclass correlation coefficient for interobserver reliability of the SAQ method was 0.81 (95% confidence interval, 0.58-0.91), compared to 0.64 (95% confidence interval, 0.45-0.81) for the modified Öhberg score. The standard error of measurement and minimal detectable difference values for the SAQ method were 2.9% and 8.0%, respectively, and for the modified Öhberg score, they were 0.55 and 1.53 points.

CONCLUSIONS

The SAQ method shows good reliability to evaluate the degree of Doppler flow in patients with chronic midportion Achilles tendinopathy, and it overcomes the ceiling effect of the modified Öhberg score. Future research should focus on the relationship between the SAQ method and clinical outcomes and use this method to monitor treatment responses.

Reliability of Evaluating Achilles Tendon Vascularization Assessed With Doppler Ultrasound Advanced Dynamic Flow

OBJECTIVES

The reliability of quantifying intratendinous vascularization by high-sensitivity Doppler ultrasound advanced dynamic flow has not been examined yet. Therefore, this study aimed to investigate the intraobserver and interobserver reliability of evaluating Achilles tendon vascularization by advanced dynamic flow using established scoring systems.

METHODS

Three investigators evaluated vascularization in 67 recordings in a test-retest design, applying the Ohberg score, a modified Ohberg score, and a counting score. Intraobserver and interobserver agreement for the Ohberg score and modified Ohberg score was analyzed by the Cohen κ and Fleiss κ coefficients (absolute), Kendall τ b coefficient, and Kendall coefficient of concordance (W; relative). The reliability of the counting score was analyzed by intraclass correlation coefficients (ICC) 2.1 and 3.1, the standard error of measurement (SEM), and Bland-Altman analysis (bias and limits of agreement [LoA]).

RESULTS

Intraobserver and interobserver agreement (absolute/relative) ranged from 0.61 to 0.87/0.87 to 0.95 and 0.11 to 0.66/0.76 to 0.89 for the Ohberg score and from 0.81 to 0.87/0.92 to 0.95 and 0.64 to 0.80/0.88 to 0.93 for the modified Ohberg score, respectively. The counting score revealed an intraobserver ICC of 0.94 to 0.97 (SEM, 1.0-1.5; bias, -1; and LoA, 3-4 vessels). The interobserver ICC for the counting score ranged from 0.91 to 0.98 (SEM, 1.0-1.9; bias, 0; and LoA, 3-5 vessels).

CONCLUSIONS

The modified Ohberg score and counting score showed excellent reliability and seem convenient for research and clinical practice. The Ohberg score revealed decent intraobserver but unexpected low interobserver reliability and therefore cannot be recommended.

Physiological Tendon Thickness Adaptation in Adolescent Elite Athletes: A Longitudinal Study

Increased Achilles (AT) and Patellar tendon (PT) thickness in adolescent athletes compared to non-athletes could be shown. However, it is unclear, if changes are of pathological or physiological origin due to training. The aim of this study was to determine physiological AT and PT thickness adaptation in adolescent elite athletes compared to non-athletes, considering sex and sport. In a longitudinal study design with two measurement days (M1/M2) within an interval of 3.2 ± 0.8 years, 131 healthy adolescent elite athletes (m/f: 90/41) out of 13 different sports and 24 recreationally active controls (m/f: 6/18) were included. Both ATs and PTs were measured at standardized reference points. Athletes were divided into 4 sport categories [ball (B), combat (C), endurance (E) and explosive strength sports (S)]. Descriptive analysis (mean ± SD) and statistical testing for group differences was performed (α = 0.05). AT thickness did not differ significantly between measurement days, neither in athletes (5.6 ± 0.7 mm/5.6 ± 0.7 mm) nor in controls (4.8 ± 0.4 mm/4.9 ± 0.5 mm, p > 0.05). For PTs, athletes presented increased thickness at M2 (M1: 3.5 ± 0.5 mm, M2: 3.8 ± 0.5 mm, p < 0.001). In general, males had thicker ATs and PTs than females (p < 0.05). Considering sex and sports, only male athletes from B, C, and S showed significant higher PT-thickness at M2 compared to controls (p ≤ 0.01). Sport-specific adaptation regarding tendon thickness in adolescent elite athletes can be detected in PTs among male athletes participating in certain sports with high repetitive jumping and strength components. Sonographic microstructural analysis might provide an enhanced insight into tendon material properties enabling the differentiation of sex and influence of different sports.

Acute effect of running exercise on physiological Achilles tendon blood flow

Sonographically detectable intratendinous blood flow (IBF) is found in 50%-88% of Achilles tendinopathy patients as well as in up to 35% of asymptomatic Achilles tendons (AT). Although IBF is frequently associated with tendon pathology, it may also represent a physiological regulation, for example, due to increased blood flow in response to exercise. Therefore, this study aimed to investigate the acute effects of a standardized running exercise protocol on IBF assessed with Doppler ultrasound (DU) "Advanced dynamic flow" in healthy ATs. 10 recreationally active adults (5 f, 5 m; 29±3 years, 1.72±0.12 m, 68±16 kg, physical activity 206±145 minute/wk) with no history of AT pain and inconspicious tendon structure performed 3 treadmill running tasks on separate days (M1-3) with DU examinations directly before and 5, 30, 60, and 120 minutes after exercise. At M1, an incremental exercise test was used to determine the individual anaerobic threshold (IAT). At M2 and M3, participants performed 30- minute submaximal constant load tests (CL₁ /CL₂ ) with an intensity 5% below IAT. IBF in each tendon was quantified by counting the number of vessels. IBF increased in five ATs from no vessels at baseline to one to four vessels solely detectable 5 minutes after CL₁ or CL₂ . One AT had persisting IBF (three vessels) throughout all examinations. Fourteen ATs revealed no IBF at all. Prolonged running led to a physiological, temporary appearance of IBF in 25% of asymptomatic ATs. To avoid exercise-induced IBF in clinical practice, DU examinations should be performed after 30 minutes of rest.