A New Quantitative Tool for the Ultrasonographic Assessment of Tendons: A Reliability and Validity Study on the Patellar Tendon

Ultrasound is widely used for tendon assessment due to its safety, affordability, and portability, but its subjective nature poses challenges. This study aimed to develop a new quantitative analysis tool based on artificial intelligence to identify statistical patterns of healthy and pathological tendons. Furthermore, we aimed to validate this new tool by comparing it to experts' subjective assessments. A pilot database including healthy controls and patients with patellar tendinopathy was constructed, involving 14 participants with asymptomatic (n = 7) and symptomatic (n = 7) patellar tendons. Ultrasonographic images were assessed twice, utilizing both the new quantitative tool and the subjective scoring method applied by an expert across five regions of interest. The database contained 61 variables per image. The robustness of the clinical and quantitative assessments was tested via reliability analyses. Lastly, the prediction accuracy of the quantitative features was tested via cross-validated generalized linear mixed-effects logistic regressions. These analyses showed high reliability for quantitative variables related to "Bone" and "Quality", with ICCs above 0.75. The ICCs for "Edges" and "Thickness" varied but mostly exceeded 0.75. The results of this study show that certain quantitative variables are capable of predicting an expert's subjective assessment with generally high cross-validated AUC scores. A new quantitative tool for the ultrasonographic assessment of the tendon was designed. This system is shown to be a reliable and valid method for evaluating the patellar tendon structure.

Measuring Ultrasonographic Thickness of the Achilles Tendon Insertion Is Less Reliable Than the Midportion in Healthy Tendons and Patients With Tendinopathy

INTRODUCTION

Ultrasound is the preferred imaging method in the diagnostic process of Achilles tendinopathy (AT). Ultrasound tissue characterization (UTC) is a frequently used, standardized and valid method to assess tendon geometry in AT patients. It is unknown whether UTC is reliable for measuring Achilles tendon thickness. The aim of the study was to assess intra- and inter-rater reliability of Achilles tendon thickness measurements using UTC in both asymptomatic individuals and patients with AT, and to evaluate if the reliability of thickness measurements differs between the midportion and insertional area.

METHODS

Exactly 50 patients with AT and 50 asymptomatic individuals were included. Using the conventional US and standardized UTC procedure maximum thickness was measured in the midportion and insertion region. To determine inter- and intra-rater reliabilities, the intraclass correlation coefficient (ICC) was used.

RESULTS

The ICC values for inter- and intra-rater reliability were classified as "excellent," for the AT group (0.93 [95% CI: 0.88-0.96] and 0.95 [0.92-0.97]) and asymptomatic participants (0.91 [0.87-0.94] and 0.94 [0.92-0.96]). The reliability of measuring tendon thickness in the midportion region was "excellent," with both inter-rater (0.97 [0.95-0.98]) and intra-rater (0.98 [0.96-0.99]) ICC values indicating high levels of agreement. In the insertional region, ICC values for inter-rater (0.79 [0.69-0.87]) and intra-rater (0.89 [0.84-0.93]) reliability were "moderate to good."

CONCLUSION

We showed excellent reliability for measuring the US thickness of the midportion and good reliability of measuring the insertional region in patients with AT. Significantly lower ICCs were observed for the reliability of thickness measurements in the insertional region when compared with the midportion.

Ultrasonographic Evaluation of Thickness and Stiffness of Achilles Tendon and Plantar Fascia in Type 2 Diabetics Patients: A Cross-sectional Observation Study

Background

Diabetes mellitus (DM) can contribute to the development of foot ulcers, a known complication of DM with a high financial and social burden. Achilles tendon (AT) and plantar fascia (PF) are well known to play an important role in foot biomechanics. The present study focuses on the alteration in thickness and stiffness of the AT and PF in Type 2 DM patients compared with the normal controls.

Methods

A cross-sectional observational study was conducted with 55 DM patients and 55 healthy volunteers as controls. The thickness of the AT and PF were measured using B-mode ultrasound and stiffness was measured using shear wave elastography. Both the thickness and stiffness in the patient group and controls were compared. The values were also compared with the clinical and demographic profiles of the patients.

Results

DM patients had considerably thicker AT and PF than controls (P < 0.05); mean values of AT thickness for DM patients and controls were 5.66 ± 0.54 mm and 4.61 ± 0.39 mm, respectively, and for PF were 2.53 ± 0.51 mm and 1.97 ± 0.19 mm, respectively. Furthermore, the stiffness of AT and PF was significantly (P < 0.05) lower in DM patients compared to controls, suggestive of softening of AT and PF in Type 2 DM patients. Mean values of shear wave velocity for DM patients and controls in AT were 5.53 ± 0.54 m/s and 7.25 ± 0.61 m/s, respectively, and for PF, 4.53 ± 0.89 m/s and 6.28 ± 0.88 m/s, respectively.

Conclusion

We conclude that there is softening and thickening of the AT and PF in Type 2 DM patients, which can impair foot biomechanics.

Sound touch elastography of Achilles tendons in patients with type 2 diabetes mellitus versus healthy adults

BACKGROUND

The studies of the effect of diabetes on the stiffness of Achilles tendon (AT) tissue remain inconclusive, we believe it is necessary to find a reliable method which can be used to detect the stiffness changes of the AT in the diabetic state. The objective of the present study was to investigate the effectiveness of sound touch elastography (STE) as a tool for detecting diabetic Achilles tendinopathy.

METHODS

We conducted a retrospective review of 180 participants, consisting of 82 patients with type 2 diabetes mellitus (T2DM) and 98 healthy adults, who had undergone AT ultrasonography. Young 's modulus (E) values of the distal, middle, and proximal segments of bilateral ATs of all participants were measured using STE technique. The E values of each AT segment between the case and control group were compared.

RESULTS

The E values of the three segments of ATs in T2DM patients were lower than the healthy controls (P < 0.05). In both groups, the E values of the distal segments were lower than those of the middle segments, and the latter were lower than those of the proximal segments (P < 0.05). The E value of each segment of AT was inversely related to FPG, HbA1c, and diabetes duration (P < 0.05). The best cut-off points for the E values of the three segments of the AT for detecting diabetic tendinopathy were 347.44 kPa (AUC, 0.779), 441.57 kPa (AUC, 0.692), and 484.35 kPa (AUC, 0.676), respectively.

CONCLUSION

STE can be used as a complementary diagnostic tool for the diagnosis of diabetic Achilles tendinopathy.

Achilles Tendon and Patellar Tendon Structure in Combat Soldiers Following Prevention Exercises

INTRODUCTION

Military training that increases physical stress on musculoskeletal morphology also increases the risk of orthopedic injuries. Somatosensory prevention programs that reduce stress and improve functionality could be beneficial for better organization of tendon structure. The aim of this study was to investigate the impact of a somatosensory prevention exercise on the tendon structure (percentage of echo-type fibers; A-P and M-L diameters and cross-sectional area) of the Achilles tendon and patellar tendon among combat soldiers.

MATERIALS AND METHODS

These tendons of male Infantry soldiers aged 18-21 were screened before and after a 14-week training course. The intervention group, who performed preventative exercises, included 108 soldiers (BMI = 23.85 ± 2.76), while the control group, who participated in the same military course without these exercises, included 98 soldiers (BMI = 24.26 ± 4.03). Ultrasound scanning for tendon structure included percent of echo-type I-IV fibers, A-P diameter, M-L diameter, and cross-sectional area parameters.

RESULTS

Time by group interaction was found for echo-type I and II in both tendons. No significant differences were found between the two groups in the pretesting percentage of echo-type IV fibers of the Achilles tendon (P = .522), in echo-type III fibers of the Achilles tendon (P = .833), and echo-type IV fibers of the patellar tendon (P = .162). Greater pre-post differences in echo-type III and IV fibers were found in the control group compared with the intervention group for both the Achilles tendon (P = .021, P = .002) and the patellar tendon (P < .001, P < .001).

CONCLUSION

Increased damaged fibers (echo-type III and IV) of both tendons were found among the control group, yet not among soldiers who performed prevention exercises.

Achilles and patellar tendon structure following a prevention program in male combat soldiers

OBJECTIVES

The aims of the study were to compare the prevalence of soldiers with musculoskeletal symptoms between soldiers that participated in a prevention program (INT) and a control group (CONT); and, to assess whether 'high risk' for a symptom indicator [participants with patellar tendon (PT) echo-type III+IV >10% or Achilles tendon (AT) echo-type III >8.5%] applies when a prevention intervention is used.

METHODS

Soldiers from two consecutive infantry commanders courses (year 1-CONT, n = 165; year 2-INT, n = 196) were examined pre-course for AT and PT structure using ultrasound tissue characterization (UTC), and their musculoskeletal overuse symptoms were assessed and recorded by military physicians throughout the course. A prevention program was provided to the INT group (year 2) during the 14-week course.

RESULTS

No significant differences were found in the prevalence of soldiers with symptoms between the two groups [INT: 39 (19.9%), CONT: 40 (24.2%); p = .32]. Using the indicator at baseline, 20 soldiers (10.2%) were suggested to be at 'high risk.' Of those 20 soldiers, 17 actually had symptoms during the course (positive predictive value-85%). The prevalence of soldiers with a suggested 'high risk' according to our indicator who had no symptoms during the course was low (3/20, 15%). Twenty-two soldiers who had symptoms during the course had not been suggested to be at 'high risk' by our indicator.

CONCLUSION

Our intervention did not reduce the prevalence of soldiers with symptoms. Our 'high risk' pre-course, AT and PT structure indicator is valid and can be used as a screening tool to reduce the prevalence of symptoms in combat soldiers; with the caution that soldiers that were not identified by the indicator, might also have symptoms along the course.

Altered regional 3D shear wave velocity patterns in youth competitive alpine skiers suffering from patellar tendon complaints - A prospective case-control study

AbstractPatellar tendon (PT) complaints are frequent throughout the population, with increased occurrence in athletes and, particularly, in youth competitive alpine skiers. Timely detection and treatment might improve prospects of recovery. Diagnostic modalities in clinical use to date rely on pain symptoms, manual palpation, and potentially, magnetic resonance imaging (MRI); however, MRI-based imaging yields limited sensitivity. Quantitatively measuring the morphological and mechanical properties of PTs by means of B-mode ultrasound and shear wave elastography (SWE), instead, may allow improved diagnosis or even early detection. We performed B-mode scans and three-dimensional ultrasound shear wave velocity (SWV) mapping and MRI of the PT in 106 youth skiers. A prospective one-year survey on health problems combined with clinical assessments served to categorize symptomatic and asymptomatic youth skiers. Skiers suffering from distal or proximal tendon complaints showed lower SWV in the respective tendon region than asymptomatic skiers (p = 0.035 and p = 0.019, respectively). Youth skiers with distal tendon complaints additionally exhibited decreased SWV in the proximal region compared to asymptomatic counterparts (p = 0.020). Cross-validated analysis of retrospective prediction indicated sensitivity and specificity in detecting tendon complaints in the range of 0.606-0.621 and 0.536-0.650, respectively. MRI detected distal tendon complaints with a sensitivity of 0.410 (12/29) but failed to detect any proximal cases. This study agrees with the most recent literature in that SWE holds promise as a valuable adjunct modality for the diagnosis of PT complaints or even the detection of subclinical prestages. However, to evaluate its prospective predictive value, long-term studies are warranted.

An Isometric and Functionally Based 4-Stage Progressive Loading Program in Achilles Tendinopathy: A 12-Month Pilot Study

Background

Achilles tendinopathy (AT) is a common musculoskeletal disorder, and its management remains challenging. Hypothesis/Purpose. By conducting a pilot study, we aimed to assess the feasibility, safety, and clinical improvement of a new home-based 4-stage rehabilitation program with progressive loading including isometric exercises on a small scale prior to setting up a randomized controlled trial.

Methods

Ten recreational athletes with chronic midportion AT were included. The primary outcome was change in VISA-A score after 1, 2, 3, 6, and 12 months. Secondary outcomes included tenderness on palpation of the tendon and ultrasonographic changes after 6 months.

Results

Average VISA-A improvements of 26.9 points (P=0.004) and 35.4 points (P=0.006) were observed at 6- and 12-month follow-up, respectively. Tenderness on palpation of the tendon (0-10) was reduced from 5.5 to 2.5 (P < 0.001). Color Doppler ultrasound activity (0-4) was reduced by 50%, from an average of grade 2 to grade 1 (P=0.023). The hypoechoic cross-sectional area of the Achilles tendon was reduced from an average of 29.1% to 8.5% (P=0.001). Tendon thickness showed no statistically significant change (P=0.415).

Conclusion

Following the 4-stage rehabilitation program for AT based on isometric training and progressive loading, we observed improvement in both VISA-A score and ultrasonography in a group of athletes who had previously failed to benefit from standard AT rehabilitation. The study was feasible in terms of high adherence to the program and with no observed safety issues. The results of this pilot study support a further assessment of this specific approach for rehabilitation in a future randomized controlled trial.

Current understanding of the diagnosis and management of the tendinopathy: An update from the lab to the clinical practice

Tendinopathy is labeled by many authors as a troublesome, common pathology, present in up to 30% medical care consultations involving musculoskeletal conditions. Despite the lasting interest for addressing tendon pathology, current researchers agree that even the exact definition of the term tendinopathy is unclear. Tendinopathy is currently diagnosed as a clinical hypothesis based on the patient symptoms and physical context. One of the main goals of current clinical management is to personalize treatment approaches to adapt them to the many different needs of the population. Tendons are complex structures that unite muscles and bones with two main objectives: to transmit forces and storage and release energy. Regarding the tensile properties of the tendons, several authors argued that tendons have higher tensile strength compared with muscles, however, are considered less flexible. Tendinopathy is an accepted term which is used to indicated a variety of tissue conditions that appear in injured tendons and describes a non-rupture damage in the tendon or paratendon, which is intensified with mechanical loading Even when the pathoetiology of tendinopathy is unclear, there is a wide array of treatments available to treat and manage tendinopathy. Although tendinitis usually debuts with an inflammatory response, the majority of chronic tendinopathies do not present inflammation and so the choosing of treatment should vary depending on severity, compliance, pain and duration of symptoms. The purpose of this article is to review and provide an overview about the currently research of the tendon diagnosis, management and etiology.

Management of Patellar Tendinopathy Through Monitoring, Load Control, and Therapeutic Exercise: A Systematic Review

CONTEXT

Patellar tendinopathy presents with persistent tendon pain located in the lower pole of the patella and loss of function related to mechanical load. Although its pathogenesis is not completely clear, conservative treatment including exercise is the main intervention of patellar tendinopathy treatment.

OBJECTIVE

To describe the efficacy of patellar tendinopathy management through therapeutic exercise, and control and monitoring of loads.

EVIDENCE ACQUISITION

MEDLINE, WoS, Cochrane Plus, PEDro, and the gray literature were searched from inception to July 2021. Based on the PICO strategy, the inclusion criteria were clinical trials published in English or Spanish; outcomes of function, pain, and strength; patients with patellar tendinopathy with no age or gender limitations; using an active intervention; and at least a methodological quality equal to or greater than 3 points on the Jadad scale. All data were analyzed by 2 independent reviewers (P.N.-M. and D.H.-G.). Studies were qualitatively synthesized using a descriptive synthesis. The methodological quality and risk of bias assessment were performed with the PEDro and Jadad scale, respectively.

EVIDENCE SYNTHESIS

A total of 136 articles were identified, of which 12 met the eligibility criteria. All of them were regarded as presenting a moderate risk of bias and their methodological quality was considered acceptable to good. Recovering patellar tendinopathy with therapeutic exercise seems to significantly improve function, pain, and strength after intervention and even lasted over time.

CONCLUSION

A treatment based on load monitoring and physical exercise has proven to be effective in rehabilitating patellar tendinopathy, with positive results in the short and medium term.

Effects of and Response to Mechanical Loading on the Knee

Mechanical loading to the knee joint results in a differential response based on the local capacity of the tissues (ligament, tendon, meniscus, cartilage, and bone) and how those tissues subsequently adapt to that load at the molecular and cellular level. Participation in cutting, pivoting, and jumping sports predisposes the knee to the risk of injury. In this narrative review, we describe different mechanisms of loading that can result in excessive loads to the knee, leading to ligamentous, musculotendinous, meniscal, and chondral injuries or maladaptations. Following injury (or surgery) to structures around the knee, the primary goal of rehabilitation is to maximize the patient's response to exercise at the current level of function, while minimizing the risk of re-injury to the healing tissue. Clinicians should have a clear understanding of the specific injured tissue(s), and rehabilitation should be driven by knowledge of tissue-healing constraints, knee complex and lower extremity biomechanics, neuromuscular physiology, task-specific activities involving weight-bearing and non-weight-bearing conditions, and training principles. We provide a practical application for prescribing loading progressions of exercises, functional activities, and mobility tasks based on their mechanical load profile to knee-specific structures during the rehabilitation process. Various loading interventions can be used by clinicians to produce physical stress to address body function, physical impairments, activity limitations, and participation restrictions. By modifying the mechanical load elements, clinicians can alter the tissue adaptations, facilitate motor learning, and resolve corresponding physical impairments. Providing different loads that create variable tensile, compressive, and shear deformation on the tissue through mechanotransduction and specificity can promote the appropriate stress adaptations to increase tissue capacity and injury tolerance. Tools for monitoring rehabilitation training loads to the knee are proposed to assess the reactivity of the knee joint to mechanical loading to monitor excessive mechanical loads and facilitate optimal rehabilitation.

Quantitative ultrasound imaging of soft biological tissues: a primer for radiologists and medical physicists

Quantitative ultrasound (QUS) aims at quantifying interactions between ultrasound and biological tissues. QUS techniques extract fundamental physical properties of tissues based on interactions between ultrasound waves and tissue microstructure. These techniques provide quantitative information on sub-resolution properties that are not visible on grayscale (B-mode) imaging. Quantitative data may be represented either as a global measurement or as parametric maps overlaid on B-mode images. Recently, major ultrasound manufacturers have released speed of sound, attenuation, and backscatter packages for tissue characterization and imaging. Established and emerging clinical applications are currently limited and include liver fibrosis staging, liver steatosis grading, and breast cancer characterization. On the other hand, most biological tissues have been studied using experimental QUS methods, and quantitative datasets are available in the literature. This educational review addresses the general topic of biological soft tissue characterization using QUS, with a focus on disseminating technical concepts for clinicians and specialized QUS materials for medical physicists. Advanced but simplified technical descriptions are also provided in separate subsections identified as such. To understand QUS methods, this article reviews types of ultrasound waves, basic concepts of ultrasound wave propagation, ultrasound image formation, point spread function, constructive and destructive wave interferences, radiofrequency data processing, and a summary of different imaging modes. For each major QUS technique, topics include: concept, illustrations, clinical examples, pitfalls, and future directions.

Six weeks of intensive rehearsals for the Swan Lake ballet shows ultrasound tissue characterization changes of the Achilles tendons in dancers

The objective was to investigate, first, whether six weeks of intensive ballet dance exposure is associated with structural and clinical changes in the Achilles tendon; second, the importance of demographics, self-reported Achilles pain, and generalized joint hypermobility (GJH). Data were collected at baseline and at six weeks' follow-up, using Achilles tendon ultrasound tissue characteristics (UTC) as primary outcome (percentage distribution of echo-type I-IV: type I = intact and aligned bundles, type II = discontinuous/wavy bundles, type III = fibrillar, and type IV = amorphous cells/fluid). Secondary outcomes included clinical signs of Achilles tendinopathy, Achilles tendon pain during single-leg heel raise, self-reported symptoms (VISA-A questionnaire), and GJH. Sixty-three ballet dancers (aged 18-41) participated. From baseline to follow-up, UTC echo-type I decreased significantly (β = -3.6, p = 0.001; 95% CI: -5.8;-1.4), whereas echo-type II increased significantly (β = 3.2, p < 0.0001, 95% CI: 1.6;4.8). Furthermore, a significant effect of limb (left limb showed decreased echo-type I and increased echo-type III + IV) and sex (women showed decreased echo-type I and increased in type II) was found. No significant changes in the remaining secondary outcomes were found. Ballet dancers showed structural changes in UTC, corresponding to a decreased echo-type I distribution after six weeks of rehearsing for Swan Lake ballet. No changes in self-reported symptoms, clinical signs of Achilles tendinopathy, and single-leg heel raise test were seen from pre- to post-rehearsal. Thus, UTC changes in the Achilles tendon seem to appear earlier than clinical signs of tendinopathy.

Identifying achilles tendon structure differences by ultrasound tissue characterization in asymptomatic individuals

Ultrasound Tissue Characterization (UTC) is a modality that can be utilized to characterize tendon tissue structure using ultrasonographic imaging paired with a computer algorithm to distinguish echo-types. Several studies have demonstrated UTCs ability to distinguish Achilles tendon morphology changes, but no study has established normative data of the Achilles tendon in the general population. The aim of this study was to determine UTC echo-type distribution in the Achilles tendon in an asymptomatic population. UTC scans were completed and analyzed on 508 participants without Achilles tendinopathy. Dedicated UTC-algorithms were used to distinguish and calculate echo-type percentages and the fiber type distribution was compared. The overall sample echo-type percentages demonstrated greater levels of Type I and II echo-types, 65.73% and 32.00%, respectively, and lower levels of Type III and IV echo-types, 1.74% and 0.57%, respectively. In addition, females had lower levels of Echo-type I compared to men and greater levels of echo-type II (p < 0.001). We also found that African-Americans had significantly greater amounts of echo-type I and lesser amounts of echo-type II when compared to Caucasians (p < 0.05). The results of this study create a normative data set for future UTC studies to utilize as a baseline for the evaluation of Achilles tendons. In addition, it demonstrated tendon type differences between sexes and races that need to be accounted for in future studies.

Effect of Autologous Expanded Bone Marrow Mesenchymal Stem Cells or Leukocyte-Poor Platelet-Rich Plasma in Chronic Patellar Tendinopathy (With Gap >3 mm): Preliminary Outcomes After 6 Months of a Double-Blind, Randomized, Prospective Study

BACKGROUND

Patellar tendinopathy is common. The success of traditional management, including isometric or eccentric exercises combined with shockwave therapy and even surgery, is limited. Therefore, it is important to determine whether biological treatments such as ultrasound-guided intratendinous and peritendinous injections of autologous expanded bone marrow mesenchymal stem cells (BM-MSCs) or leukocyte-poor platelet-rich plasma (Lp-PRP) improve clinical outcomes in athletic patients with patellar tendinopathy.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

A prospective, double-blinded, randomized, 2-arm parallel group, active controlled, phase 1/2 single-center clinical study was performed in patients who had proximal patellar tendinopathy with a lesion >3 mm. A total of 20 participants (age 18-48 years) with pain for >4 months (mean, 23.6 months) and unresponsive to nonoperative treatments were randomized into 2 groups. Of these, 10 participants were treated with BM-MSC (20 × 10⁶ cells) and 10 with Lp-PRP. Both groups performed the same postintervention rehabilitation protocol. Outcomes included the Victorian Institute of Sport Assessment for pain (VISA-P), self-reported tendon pain during activity (visual analog scale [VAS]), muscle function by dynamometry, tendon thickness and intratendinous vascularity by ultrasonographic imaging and Doppler signal, ultrasound tissue characterization (UTC) echo type changes, and magnetic resonance imaging (MRI) T2-weighted mapping changes. Participants were followed longitudinally for 6 months.

RESULTS

The average VAS scores improved in both groups at all time points, and there was a significant reduction in pain during sporting activities (P < .05). In both groups, the average mean VISA-P scores at 6 months were significantly increased compared with baseline (66 BM-MSC group and 72.90 Lp-PRP group), with no significant differences in VAS or VISA-P scores between the groups. There were statistically significant greater improvements in tendon structure on 2-dimensional ultrasound and UTC in the BM-MSC group compared with the Lp-PRP group at 6 months. Similarly, the BM-MSC group demonstrated significant evidence of restoration of tendon structure on MRI compared with the Lp-PRP group at 6 months. Only the participants in the BM-MSC group showed evidence of normalization of tendon structure, with statistically significant differences between the groups on T2-weighted, fat-saturated sagittal and coronal scans and hypersignal in T2-weighted on spin-echo T2-weighted coronal MRI scan. Both treatments were safe, and no significant adverse events were reported in either group.

CONCLUSION

Treatment with BM-MSC or Lp-PRP in combination with rehabilitation in chronic patellar tendinopathy is effective in reducing pain and improving activity levels in active participants. Participants who received BM-MSC treatment demonstrated greater improvement in tendon structure compared with those who received Lp-PRP.

REGISTRATION

2016-001262-28 (EudraCT identifier); NCT03454737 (ClinicalTrials.gov identifier).

Physical Activity and Investigation With Magnetic Resonance Imaging Partly Explain Variability in the Prevalence of Patellar Tendon Abnormalities: A Systematic Review With Meta-analysis of Imaging Studies in Asymptomatic Individuals

OBJECTIVE

To estimate the pooled prevalence of, and factors associated with, the presence of patellar tendon abnormalities observed on imaging in people without symptoms.

DESIGN

Systematic review with stratified meta-analysis and meta-regression.

LITERATURE SEARCH

We searched Embase, Scopus, MEDLINE, CINAHL, SPORTDiscus, and Web of Science from 1980 to August 2020.

STUDY SELECTION CRITERIA

We included studies that reported the prevalence of asymptomatic patellar tendon abnormalities on imaging. We excluded studies of participants with current tendon pain, a history of tendon pain, or other systemic conditions.

DATA SYNTHESIS

Stratification and meta-regression of studies based on study-level descriptive statistics (mean age, body mass index, proportion of female participants, physical activity participation, imaging modality) were performed using a random-effects model to account for between-study heterogeneity. Risk of bias was assessed using the modified Newcastle-Ottawa scale.

RESULTS

Meta-analysis of 64 studies (7125 limbs from 4616 participants) found significant between-study heterogeneity (I²≥90%, P<.01), which precluded a summary prevalence estimate. Heterogeneity was partially explained by studies that included participants who were physically active and studies that assessed tendon abnormalities using magnetic resonance imaging compared to ultrasound (P<.05). Mean age, body mass index, proportion of female participants, and sample size did not explain the remaining heterogeneity.

CONCLUSION

There was substantial variability in the reported prevalence of asymptomatic patellar tendon abnormalities. A clear and valid method is needed to assess and report the presence of patellar tendon abnormalities to increase research capacity and establish the clinical value of imaging the patellar tendon. J Orthop Sports Phys Ther 2021;51(5):216-231. Epub 28 Mar 2021. doi:10.2519/jospt.2021.10054.

Substantiating the Use of Ultrasound Tissue Characterization in the Analysis of Tendon Structure: A Systematic Review

OBJECTIVE

To determine the role of ultrasound tissue characterization (UTC) in predicting, diagnosing, and monitoring tendon structure and/or tendinopathy. In addition, this study aims to provide recommendations for standardized methodology of UTC administration and analysis.

DATA SOURCE

The PubMed, Embase, and Web of Science databases were searched (up to September 2018). All scientific literature concerning the use of UTC in assessing tendons was collected. The initial search resulted in a total of 1972 hits, and after screening by eligibility criteria, 27 articles were included.

RESULTS

In total, 18 investigating the Achilles tendon, 5 the patellar tendon, and 4 both Achilles and patellar tendons were included. The methods of UTC administration and analysis differed and were not uniform. The studies showed that the use of UTC to predict Achilles tendinopathy (AT) is inconclusive, but that a higher amount of tendon disorganization increases the risk of developing patellar tendinopathy (PT). In terms of diagnosis, UTC might provide additional information in AT cases. In addition, promising results were found for the use of UTC in both AT and PT in monitoring the effect of load or treatment on tendon structure.

CONCLUSION

More research regarding the use of UTC in predicting tendon pathology is required. Ultrasound tissue characterization seems useful as an adjunct diagnostic modality because it can be used to differentiate symptomatic from asymptomatic tendons. In addition, UTC is a promising device to be used to monitor changes in tendon structure in response to load or treatment. Moreover, we provide recommendations of a standardized protocol concerning the methods of UTC measurement and analysis.

Differences in Biomechanical Loading Magnitude During a Landing Task in Male Athletes with and without Patellar Tendinopathy

CONTEXT

Prior research has not established if overloading or underloading movement profiles are present in symptomatic and asymptomatic athletes with patellar tendon structural abnormality (PTA) compared to healthy athletes.

OBJECTIVE

The purpose was to compare involved limb landing biomechanics between male athletes with and without patellar tendinopathy.

DESIGN

Cross-sectional study Setting: Laboratory Patients or Other Participants: 43 males were grouped based on patellar tendon pain & ultrasound imaging of the proximal patellar tendon: symptomatic with PTA (SYM-PTA; n=13; 20±2yrs; 1.8±0.1m; 84±5kg), asymptomatic with PTA (ASYM-PTA; n=15; 21±2yrs; 1.8±0.1m; 82±13kg), and healthy control (CON; n=15; 20±2yrs; 1.8±0.1m; 79±12kg).

MAIN OUTCOME MEASURES

3D biomechanics were collected during double-limb jump-landing. Kinematic (knee flexion angle (KF)) and kinetic (vertical ground reaction force (VGRF); internal knee extension moment (KEM); patellar tendon force (FPT)) variables were analyzed as continuous waveforms during the stance phase for the involved limb. Mean values were calculated for each 1% of stance, normalized over 202 data points (0-100%), and plotted with 95% confidence intervals. Statistical significance was defined as a lack of 95% CI overlap for ≥ 6 consecutive data points.

RESULTS

SYM-PTA had lesser KF than CON throughout the stance phase. ASYM-PTA had lesser KF than CON in the early and late stance phase. SYM-PTA group had lesser KEM and FPT than CON in early stance, as well as ASYM-PTA in mid-stance.

CONCLUSIONS

Male athletes with SYM-PTA demonstrated a patellar tendon load-avoidance profile compared to ASYM-PTA and CON athletes. ASYM-PTA did not show evidence of overloading compared to CON. Our findings support the need for individualized treatments for athletes with tendinopathy to maximize load-capacity.

TRIAL REGISTRY

ClinicalTrials.gov (#XXX).

Diagnostic accuracy of examination tests for lateral elbow tendinopathy (LET) - A systematic review

BACKGROUND

Reviews on the diagnostic performance of the examination tests for lateral elbow tendinopathy (LET) based on updated context-specific tools and guidelines are missing.

PURPOSE

To review the diagnostic accuracy of examination tests used in LET.

DESIGN

Systematic review following PRISMA-DTA guidelines.

METHODS

We searched MEDLINE, PubMed, CINAHL, EMBASE, PEDro, ScienceDirect, and Cochrane Library databases. The QUADAS-2 checklist was used to assess the methodological quality of the eligible studies. We included diagnostic studies reporting the accuracy of physical examination tests or imaging modalities used in patients with LET.

RESULTS

Twenty-four studies with 1370 participants were identified reporting the diagnostic performance of Ultrasound Imaging (USI) (18 studies), physical examination tests (2 studies) and Magnetic Resonance Imaging (MRI) (4 studies). Most studies (97%) were assessed with "unclear" or "high risk" of bias. Sonoelastography showed the highest sensitivity (75- 100%) and specificity (85- 96%). Grayscale with or without Doppler USI presented poor to excellent values (sensitivity: 53%-100%, specificity: 42%-90%). MRI performed better in the diagnosis of tendon thickening and enthesopathy (sensitivity and specificity: 81%-100%). The Cozen's test reported high sensitivity (91%) while a grip strength difference of 5%-10% between elbow flexion and extension showed high sensitivity (78%-83%) and specificity (80%-90%).

CONCLUSIONS

Cozen's test and grip strength measurement present high accuracy in the diagnosis of LET but are poorly investigated. USI and MRI provide variable diagnostic accuracy depending on the entities reported and should be recommended with caution when differential diagnosis is necessary. Substantial heterogeneity was found in inclusion criteria, operator/ examiner, mode of application, type of equipment and reference standards across the studies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO ID CRD42020160402.

The Influence of a 14-Week Infantry Commanders Courses on the Achilles Tendon and Patellar Tendon Structure

INTRODUCTION

Alternated tendon structure may raise stress to the musculoskeletal structures and may increase the potential for overuse injury. Screening the tendon structure of soldiers pre- and post-participation in a strenuous combat course is essential. The aim of the present study was to investigate the influence of a 14-week infantry commanders courses on the Achilles tendon (AT) structure and patellar tendon (PT) structure in combat soldiers.

MATERIALS AND METHODS

Ninety-eight participants from an infantry commanders course were screened pre- and post-course for the AT and PT structures, using ultrasonographic tissue characterizaton (UTC) imaging to capture a 3D structure of four echo-type fibers (I-IV).

RESULTS

In both tendons, the mean relative frequency of echo-type I fibers significantly decreased from pre- to post-testing, with a significant increase in the relative frequency of echo-types II, III, and IV fibers. In the AT, 60.2% of the subjects showed positive differences (between pre- and post-testing in the echo-type III + IV fiber ("worsened" tendon structure), whereas in the PT, 92.2% of the subject showed an increased frequency. No significant correlation (r = 0.108; P = .324) was found between the differences of echo-type III + IV fibers of the AT and that of the PT.

CONCLUSIONS

Loads to the musculoskeletal structures along the combat course increased the mean relative frequency of the "reduced" echo-type fibers (III + IV) in both the AT structure and the PT structure. Yet, whereas in the AT around 40% of the soldiers showed an improved tendon structure along the course, in the PT less than 10% of the soldiers showed that improvement. Soldiers and commanders should be aware of the different influence of the loading exercises along the course on the AT and on the PT structure, as "reduced" tendons structure might put the soldiers at higher risk for injury in the future.

Load progression criteria in exercise programmes in lower limb tendinopathy: a systematic review

OBJECTIVE

The objective of this study is to summarise and analyse the current literature about what progression criteria are applied in loading exercise programmes in lower limb tendinopathies and their evidence and effectiveness.

DESIGN

Systematic review.

METHODS

PubMed, Embase, Scopus and PEDro were searched from inception to 24 September 2020. The inclusion criteria were randomised controlled trials that included patients with midportion Achilles, patellar or gluteal tendinopathy; assessed function, pain or performance; included at least one group where progressive physical exercise was administered as monotherapy; included at least a control group. We excluded studies that included subjects with previous tendon surgical treatment; studies with control group that conducted a supplemented modality of the exercise performed in the intervention group. A narrative synthesis was conducted. Cohen's d and the percentage of change of main clinical and performance outcomes were obtained. Methodological quality was assessed using the PEDro scale.

RESULTS

Thirty studies that described progression criteria were included. Six types of criteria grouped in two categories were identified and included in a new classification proposal: pain as a primary criterion (evoking and avoid-pain based), and pain and symptom control as a secondary criterion (conditioning stages, fatigue-based, subjective perception and temporary linear increase). Most of the studies applied a pain-based criterion. Criteria based on conditioning stages were also commonly applied. Other criteria such as fatigue, a temporary linear increase, or the subjective perception of the patient's abilities were occasionally applied.

CONCLUSIONS

There is a predominant use of pain-based criteria, but the utilisation of these criteria is not supported by strong evidence. This review evidences the need for studies that compare the same exercise programme using different progression criteria. A new classification of the existing progression criteria is proposed based on the use of pain as the primary or secondary criterion.

PROSPERO REGISTRATION NUMBER

CRD42018110997.

The influence of a multidisciplinary intervention program on Achilles tendon structure in children with overweight and obesity

The effects of childhood obesity on tendon structure and its relation to physical activity are barely known. We aimed to investigate the influence of a 6-month multidisciplinary childhood obesity management program (which included dietary intervention and an exercise program) on Achilles tendon structure in overweight/obese children. Twenty-five overweight/obese children (overweight group) who participated in a 6-month multidisciplinary childhood obesity program, and 27 normal-weight controls were examined for anthropometric measurements and for Achilles tendon structure (using ultrasound tissue characterization to capture a three-dimensional structure of four echo type fibers and the cross-sectional area) at baseline, 3, and 6 months. The BMI of the overweight group significantly decreased from the pre- to the post-intervention period, (p = .002, η² = .229), yet among the control group, the BMI significantly increased (p = .002, η² = .222). Interactions (pre-post × group) showed a significant decrease in the prevalence of echo type I and in echo type III fibers and a significant increase in the prevalence of echo type II fibers and in the cross-sectional area along the intervention. No significant changes in echo type fibers were found in the control group along the 6 months.Conclusion: At pre-intervention, the overweight group had significantly "worse" tendon structure, with a lower prevalence of echo type II fiber and a higher prevalence of echo type III fibers compared with the control group. Following the 6-month intervention, the tendon structure of the overweight group was "positively" changed, with reduced echo type III fibers and increased echo type II fibers. What is Known: • Physical activity and weight reduction programs are efficient for obese children. • Obese children tend to suffer orthopedic problems and pain during physical activity. What is New: • Pre-intervention, obese children had 'worse' tendon structure compared to controls. • Following 6-month program, tendon structure of obese children 'positively' changed.

Reduced Levels of Aligned Fibrillar Structure Are Not Associated With Achilles and Patellar Tendon Symptoms

OBJECTIVE

To investigate whether the mean cross-sectional area (mCSA) of aligned fibrillar structure (AFS) was associated with the presence and severity of symptoms.

DESIGN

Prospective cohort study.

PARTICIPANTS

One hundred seventy-five elite male Australian football players completed monthly Oslo Sports Trauma Research Center overuse injury questionnaires for both the Achilles and patellar tendon over the season to ascertain the presence and severity of symptoms. At the start of the preseason, participants underwent ultrasound tissue characterization (UTC) imaging of the Achilles and patellar tendon.

MAIN OUTCOME MEASURES

Images were classified as normal or abnormal based on gray-scale ultrasound. Based on UTC quantification, the mCSA of AFS was compared between those with and without current symptoms.

RESULTS

No difference in the mCSA of AFS was observed between those with or without tendon symptoms (P < 0.05). Similar to previous findings, 80% to 92% of abnormal tendons had similar amounts of mCSA of AFS compared with normal tendon. If reduced mCSA of AFS was present, it was not associated with the presence or severity of symptoms.

CONCLUSIONS

The prevalence, development, or severity of symptoms was not associated with decreased levels of AFS in the Achilles or patellar tendon. This suggests that a lack of structural integrity is not linked to symptoms and questions the rationale behind regenerative medicine. Most tendons are able to compensate for areas of disorganization and maintain tissue homeostasis.

Sonoelastographic Evaluation of the Achilles Tendon in Patients With Type 2 Diabetes Mellitus

Diabetic foot is one of the dreaded complications of diabetes mellitus (DM). Alterations of the Achilles tendon (AT) may contribute to development of foot ulcers in diabetic patients. We evaluated the sonoelastographic abnormalities of the AT in 61 healthy volunteers and 81 patients with type 2 DM. The patients were further divided into those with and without peripheral neuropathy (PN). The AT thickness was measured in the proximal, middle and distal portions. Alterations in echo pattern were noted. The patients were found to have thicker tendons than the healthy volunteers (p < 0.01). Alterations in the echo pattern of the AT were more common in patients compared with healthy volunteers (p < 0.01). The shear wave velocity in the distal one-third of the AT was measured using shear wave elasticity imaging. Mean shear wave velocity values obtained were lower in patients compared with healthy volunteers (p < 0.001). No significant difference was found in the sonoelastographic findings of the AT in patients with and without PN. We conclude that there is softening, thickening and alterations in echo pattern of the AT in the form of hypoechogenicity, loss of fibrillar pattern and calcification at insertion in patients with type 2 DM, and these alterations could occur independent of onset of PN.

Ultrasound and clinical findings in the metacarpophalangeal joint assessment of show jumping horses in training

Background

Physical exercise is known to cause significant joint changes. Thus, monitoring joint behavior of athletic horses is essential in early disorders recognition, allowing the proper management.

Objectives

The aims of this study were to determine the morphological patterns, physical examination characteristics and ultrasound findings of show jumping horses in training and to establish a score-based examination model for physical and ultrasound follow-ups of metacarpophalangeal joint changes in these animals.

Methods

A total of 52 metacarpophalangeal joints from 26 horses who were initially in the taming stage were evaluated, and the horses' athletic progression was monitored. The horses were evaluated by a physical examination and by B-mode and Doppler-mode ultrasound examinations, starting at time zero (T0), which occurred concomitantly with the beginning of training, and every 3 months thereafter for a follow-up period of 18 months.

Results

The standardized examination model revealed an increase in the maximum joint flexion angles and higher scores on the physical and ultrasound examinations after scoring was performed by predefined assessment tools, especially between 3 and 6 months of evaluation, which was immediately after the horses started more intense training. The lameness score and the ultrasound examination score were slightly higher at the end of the study.

Conclusions

The observed results were probably caused by the implementation of a training regimen and joint adaptation to physical conditioning. The joints most likely undergo a pre-osteoarthritic period due to work overload, which can manifest in a consistent or adaptive manner, as observed during this study. Thus, continuous monitoring of young athlete horses by physical and ultrasound examinations that can be scored is essential.

Efficacy of heel lifts versus calf muscle eccentric exercise for mid-portion Achilles tendinopathy (HEALTHY): a randomised trial

OBJECTIVES

To compare the efficacy of in-shoe heel lifts to calf muscle eccentric exercise in reducing pain and improving function in mid-portion Achilles tendinopathy.

METHODS

This was a parallel-group randomised superiority trial at a single centre (La Trobe University Health Sciences Clinic, Discipline of Podiatry, Melbourne, Victoria, Australia). One hundred participants (52 women and 48 men, mean age 45.9, SD 9.4 years) with clinically diagnosed and ultrasonographically confirmed mid-portion Achilles tendinopathy were randomly allocated to either a (1) heel lifts (n=50) or (2) eccentric exercise (n=50) group. The primary outcome measure was the Victorian Institute of Sport Assessment-Achilles (VISA-A) questionnaire at 12 weeks. Differences between groups were analysed using intention to treat with analysis of covariance.

RESULTS

There was 80% follow-up of participants (n=40 per group) at 12 weeks. The mean VISA-A score improved by 26.0 points (95% CI 19.6 to 32.4) in the heel lifts group and by 17.4 points (95% CI 9.5 to 25.3) in the eccentric exercise group. On average, there was a between-group difference in favour of the heel lifts for the VISA-A (adjusted mean difference 9.6, 95% CI 1.8 to 17.4, p=0.016), which approximated, but did not meet our predetermined minimum important difference of 10 points.

CONCLUSION

In adults with mid-portion Achilles tendinopathy, heel lifts were more effective than calf muscle eccentric exercise in reducing pain and improving function at 12 weeks. However, there is uncertainty in the estimate of effect for this outcome and patients may not experience a clinically worthwhile difference between interventions.

TRIAL REGISTRATION NUMBER

ACTRN12617001225303.

Can Achilles and patellar tendon structures predict musculoskeletal injuries in combat soldiers?

Aiming to investigate whether Achilles tendon (AT) structure and patellar tendon (PT) structure are risk factors for musculoskeletal injuries in combat soldiers, 168 participants were recruited from an infantry commander's course. The AT and PT were examined pre-course using UTC to capture the structure of four echo-type fibers (I-IV). All injuries were assessed by military physicians pre-course and throughout the 14-week course. Soldiers who were injured during the course had a significantly higher pre-course prevalence of AT and PT echo-type III and echo-type IV compared to soldiers that were not injured during the course. Variables that were found to be associated with injured/non-injured participants were echo-type III + IV of the PT (OR = 1.44, 95% CI = 1.24-1.68) and echo-type III of the AT (OR = 1.69, 95% CI = 1.35-2.12). ROC analyses showed that the best model, exhibiting both high sensitivity and low specificity, was that participants with PT echo-type III + IV > 10% or AT echo-type III >8.5% had the highest risk of being injured during the course. In conclusions, the tendon structure at the beginning of high-intensity activity or physical training program might be a risk factor for subsequent injury during the course. Soldiers and high-level athletes should be aware of the cutoff points for fiber types in tendon structure that might put them at high risk for future injury. At-risk soldiers/athletes should be provided with an intervention program before they start their training program, with the aim of improving the tendon structure and preventing subsequent injury.

Does moxonidine reduce Achilles tendon or musculoskeletal pain in women with polycystic ovarian syndrome? A secondary analysis of a randomised controlled trial

BACKGROUND

Sympathetic activity and insulin resistance have recently been linked with chronic tendon and musculoskeletal pain. Polycystic ovarian syndrome is linked with insulin resistance and increased sympathetic drive and was therefore an appropriate condition to study the effects of modulating sympathetic activity on Achilles tendon and musculoskeletal symptoms.

METHODS

A secondary analysis of a double-blinded, randomised controlled trial on women with polycystic ovarian syndrome was conducted. Participants received 12 weeks of moxonidine (n = 14) or placebo (n = 18). Musculoskeletal symptom and Victorian Institute of Sport Assessment - Achilles (VISA-A) questionnaires were distributed, and ultrasound tissue characterisation quantified tendon structure at 0 and 12 weeks. 2-way ANOVA was used for multiple comparisons.

RESULTS

There was no difference in mean change in musculoskeletal symptoms (- 0.6 ± 1.7 vs - 0.4 ± 1.8, p = 0.69) or VISA-A (moxonidine - 0.2 ± 8.8 vs placebo + 4.2 ± 14.6, p = 0.24) attributable to the intervention. There was no difference in any measures of Achilles structure. Moxonidine did not reduce sympathetic drive when compared to placebo.

CONCLUSIONS

This was the first study to investigate the effects of blocking sympathetic drive on musculoskeletal and Achilles tendon symptoms in a metabolically diverse population. While the study was limited by small sample size and lack of sympathetic modulation, moxonidine did not change tendon pain/structure or musculoskeletal symptoms.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01504321 . Registered 5 January 2012.

Lower Limb Tendinopathy Tissue Changes Assessed through Ultrasound: A Narrative Review

Tendinopathy is a common disease that affects athletes, causing pain and dysfunction to the afflicted tendon. A clinical diagnose is usually combined with imaging and, among all the existing techniques, ultrasound is widely adopted. The aim of this review is to sum up the existing evidence on ultrasound as an imaging tool and guide for treatments in lower limbs tendinopathy. Using three different databases—PubMed, MEDLINE and CENTRAL—a literature search has been performed in May 2020 combining MeSH terms and free terms with Boolean operators. Authors independently selected studies, conducted quality assessment, and extracted results. Ultrasound imaging has a good reliability in the differentiation between healthy and abnormal tendon tissue, while there are difficulties in the identification of tendinopathy stages. The main parameters considered by ultrasound imaging are tendon thickness, hypoechogenicity of tendon structure and neovascularization of the tendon bound tissue. Ultrasound-guide is also used in many tendinopathy treatments and the available studies gave encouraging results, even if further studies are needed in this field.

Extracorporeal Shock Wave Therapy Immediately Affects Achilles Tendon Structure and Widespread Pressure Pain Thresholds in Healthy People: A Repeated-Measures Observational Study

OBJECTIVE

Extracorporeal shockwave therapy is a common clinical treatment for tendinopathy, yet negative effects on tendon structure have been shown in animal studies. This study aimed to investigate the effect of extracorporeal shockwave therapy in healthy participants (i.e., no Achilles tendon pain or pathology).

DESIGN

This study examined the effect of three bouts of weekly extracorporeal shockwave therapy for 3 wks in 13 healthy participants. Outcomes measures assessed were as follows: (a) Achilles tendon structure, quantified using ultrasound tissue characterization (before and 3 hrs after extracorporeal shockwave therapy), (b) pressure pain thresholds, over the Achilles tendon and common extensor tendon origin (before, immediately after, and 3 hrs after extracorporeal shockwave therapy), and (c) hop pain (before and immediately after extracorporeal shockwave therapy).

RESULTS

There was a significant reduction in echo type I (P < 0.05) and increase in echo type II (P < 0.05) at 3 hrs after the first extracorporeal shockwave therapy session that recovered to baseline levels before week 2. There were no significant changes in ultrasound tissue characterization echo pattern observed in subsequent sessions. There were increased pressure pain thresholds immediately after extracorporeal shockwave therapy at the common extensor tendon origin but no significant change at the Achilles tendon. Pressure pain thresholds returned to baseline at 3 hrs after extracorporeal shockwave therapy. There were no significant changes in pressure pain threshold in subsequent sessions.

CONCLUSIONS

Extracorporeal shockwave therapy resulted in transient changes to tendon structure and widespread hyperalgesia.

Staging achilles tendinopathy using ultrasound imaging: the development and investigation of a new ultrasound imaging criteria based on the continuum model of tendon pathology

Aim

To develop a standardised ultrasound imaging (USI)-based criteria for the diagnosis of tendinopathy that aligns with the continuum model of tendon pathology. Secondary aims were to assess both the intra-rater and inter-rater reliability of the criteria.

Methods

A criteria was developed following a face validity assessment and a total of 31 Achilles tendon ultrasound images were analysed. Intra-rater and inter-rater reliability were assessed for overall tendinopathy stage (normal, reactive/early dysrepair or late dysrepair/degenerative) as well as for individual parameters (thickness, echogenicity and vascularity). Quadratic weighted kappa (k_w) was used to report on reliability.

Results

Intra-rater reliability was ‘substantial’ for overall tendinopathy staging (k_w rater A; 0.77, 95% CI 0.59 to 0.94, rater B; 0.70, 95% CI 0.52 to 0.89) and ranged from ‘substantial’ to ‘almost perfect’ for thickness (k_w rater A; 0.75, 95% CI 0.59 to 0.90, rater B; 0.84, 95% CI 0.71 to 0.98), echogenicity (k_w rater A; 0.78, 95% CI 0.62 to 0.95, rater B; 0.73, 95% CI 0.58 to 0.89) and vascularity (k_w rater A; 0.86, 95% CI 0.74 to 0.98, rater B; 0.89, 95% CI 0.79 to 0.99). Inter-rater reliability ranged from ‘substantial’ to ‘almost perfect’ for overall tendinopathy staging (k_w round 1; 0.75, 95% CI 0.58 to 0.91, round 2; 0.81, 95% CI 0.63 to 0.99), thickness (k_w round 1; 0.65, 95% CI 0.48 to 0.83, round 2; 0.77, 95% CI 0.60 to 0.93), echogenicity (k_w round 1; 0.70, 95% CI 0.54 to 0.85, round 2; 0.76, 95% CI 0.58 to 0.94) and vascularity (k_w round 1; 0.89, 95% CI 0.79 to 0.99, round 2; 0.86, 95% CI 0.74 to 0.98). Inter-rater reliability increased from ‘substantial’ in round 1 (k_w 0.75, 95% CI 0.58 to 0.91) to ‘almost perfect’ in round 2 (0.81, 95% CI 0.63 to 0.99).

Conclusion

Intra-rater and inter-rater reliability were ‘substantial’ to ‘almost perfect’ when utilising an USI-based criteria to diagnose Achilles tendinopathy. This is the first study to use the continuum model of tendon pathology to develop an USI-based criteria to diagnose tendinopathy.

Landing Biomechanics, But Not Physical Activity, Differ in Young Male Athletes With and Without Patellar Tendinopathy

OBJECTIVE

To examine differences in biomechanical and physical activity load in young male athletes with and without patellar tendinopathy.

DESIGN

Cross-sectional cohort study.

METHODS

Forty-one young male athletes (15-28 years of age) were categorized into 3 distinct groups: symptomatic athletes with patellar tendon abnormalities (PTA) (n = 13), asymptomatic athletes with PTA (n = 14), and a control group of asymptomatic athletes without PTA (n = 14). Participants underwent a laboratory biomechanical jump-landing assessment and wore an accelerometer for 1 week of physical activity monitoring.

RESULTS

The symptomatic group demonstrated significantly less patellar tendon force loading impulse in the involved limb compared with both the control and asymptomatic groups (P<.05), with large effects (d = 0.91-1.40). There were no differences in physical activity between the 3 groups (P>.05).

CONCLUSION

Young male athletes with symptomatic patellar tendinopathy demonstrated smaller magnitudes of patellar tendon force loading impulse during landing compared to both asymptomatic athletes with patellar tendinopathy and healthy control participants. However, these 3 distinct groups did not differ in general measures of physical activity. Future investigations should examine whether comprehensively monitoring various loading metrics may be valuable to avoid both underloading and overloading patterns in athletes with patellar tendinopathy. J Orthop Sports Phys Ther 2020;50(3):158-166. Epub 6 Jan 2020. doi:10.2519/jospt.2020.9065.

Differences Between Long Distance Road Runners and Trail Runners in Achilles Tendon Structure and Jumping and Balance Performance

BACKGROUND

Load and joint kinematics change with differences in running surface. Running regularly on trails compared to roads might influence the load on the Achilles tendon and its adaptations, along with other factors such as balance, strength, and proprioception.

OBJECTIVE

To investigate Achilles tendon structure and functional tests in road and trail runners.

DESIGN

Cross-sectional study.

SETTING

Laboratory, sport sciences college.

PARTICIPANTS

The study included 26 road and 17 trail runners who run at least three times per week with a minimum of 20 km per week and who participated in running competitions over the preceding 2 years.

METHODS

Each participant was examined for Achilles tendon structure (via ultrasound tissue characterization [UTC] imaging) and underwent functional tests in addition to completing a demographic questionnaire.

MAIN OUTCOME MEASUREMENTS

The percentages of echo types I, II, III, and IV (degree of structural homogeneity) within the tendon, tendon length and width, tendon cross-sectional area (via UTC imaging); Ankle inversion movement discrimination ability (via Active Movement Extent Discrimination Apparatus device); dynamic postural balance (via Y balance test); jumping performance (by Triple hop distance test); and Hip muscle abduction muscle strength (by hand-held dynamometry).

RESULTS

Percentage of echo type I was significantly lower while echo type II was higher in the road group compared with the trail group (67.3% type I and 28.9% type II in the road group compared with 74.1% type I and 22.1% type II in the trail group, P < .001). No differences between genders were found and no significant differences between groups were found for the other tests.

CONCLUSION

Tendon integrity as examined with UTC is different between road and trail runners. This suggests an influence of running surface on Achilles tendon structure. This difference was not reflected in other tests, thus the influence of tendon structure on function needs further examination.

Achilles Tendon Tissue Structure in Children with Overweight and Children with Obesity

Aim: To investigate differences in Achilles tendon structure between children with overweight/obesity and children with normal weight.Methods: Twenty-two children with obesity, 10 children with overweight, and 44 children with normal weight participated in the study. BMI% was calculated. The Achilles tendon was examined using ultrasound tissue characterization (UTC) imaging to capture a three-dimensional structure of four echo-type fibers and a cross-sectional area.Results: A significantly higher percentile of echo-types II, a lower percentile of echo-types III and IV, and a lower cross-sectional area were found for children with normal weight compared with children with overweight/obesity (p < .05). Following a piecewise linear regression model according to tendon structure, a BMI percentile of 75% was found to be the most accurate cutoff point of the children into the "unaffected" (BMI% <75%) and "affected" tendon structure groups (BMI% ≥ 75%), as the children with BMI%≥75% already had an Achilles tendon structure similar to that of the children with overweight/obesity.Conclusions: Tendon integrity as examined with UTC differs between children with obesity and children with normal weight. Children with a BMI percentile of ≥75 already demonstrate a different tendon structure pattern compared with children with BMI percentile of <75. This may put children with obesity at a greater risk of injury and should be addressed when applying an exercise program for children with overweight/obesity.

Symptomatic Achilles Tendons are Thicker than Asymptomatic Tendons on Ultrasound Examination in Recreational Long-Distance Runners

There is a need for clinical indicators that can be used to guide the treatment of Achilles tendon complaints in recreational runners. Diagnostic ultrasound has recently been introduced for clinical decision support in tendon pain management. The aim of this study was to determine whether tendon thickness and morphological changes in the Achilles tendon detected in ultrasound examinations are associated with local symptoms in middle-age recreational long-distance runners. Forty-two Achilles tendons (21 middle-aged runners) were investigated by ultrasound examination measuring tendon thickness and a morphology score indicating tendinosis. The Generalized Estimating Equations method was applied in multiple models of factors associated with reporting a symptomatic tendon. Eleven symptomatic and 31 asymptomatic Achilles tendons were recorded. In the multiple model that used tendon thickness measured 30 mm proximal to the distal insertion, an association was found between thickness and reporting a symptomatic tendon (p < 0.001; OR 12.9; 95% CI 3.1 to 53.2). A qualitative morphology score was not found to be significantly associated with reporting a symptomatic tendon (p = 0.10). We conclude that symptomatic Achilles tendons were thicker than asymptomatic tendons on ultrasound examination among recreational long-distance runners and that the importance of parallel morphological findings need to be further investigated in prospective studies.

Acute sensory and motor response to 45-s heavy isometric holds for the plantar flexors in patients with Achilles tendinopathy

PURPOSE

The purpose of this study was to explore the immediate effects of heavy isometric plantar flexor exercise on sensory output (pain during a functional task and mechanical pain sensitivity) and motor output (plantar flexor torque) in individuals with Achilles tendinopathy.

METHODS

Sixteen subjects with Achilles tendinopathy participated in the study, mean (SD) age 48.6 (8.9) years and Victorian institute assessment-Achilles (VISA-A) score 61.3 (23.0). Sensory testing assessing pain during a functional task, mechanical pain sensitivity and motor output, and plantar flexor peak torque was completed prior to the intervention. All subjects completed a 45-s heavy isometric plantar flexor contraction and were then re-tested using the same sensory and motor tests. Motor output was assessed using isokinetic dynamometry at speeds previously identified as of interest in subjects with Achilles tendinopathy.

RESULTS

Only 9 of the 16 subjects experienced pain during a functional task, self-reported pain was 4.2 (1.9) numerical rating scale (NRS) pre-intervention and 4.9 (3.2) NRS postintervention (n.s.). Mechanical pressure sensitivity was 446.5 (± 248.5) g/mm2 pre-intervention and 411.8 (± 211.8) g/mm2 post-intervention (n.s.). Mean concentric plantar flexor torque at 90 and 225°/s was 47.1 (14.5) and 33.6 (11.6) Nm, respectively, pre-intervention and 53.0 (18.5) and 33.4 (6.6) Nm post-intervention (p = 0.039 and n.s.). Eccentric torque at 90°/s was 98.5 (34.2) Nm preintervention versus 106.0 (41.4) Nm post-intervention (n.s.).

CONCLUSION

In this exploratory study, patients with Achilles tendinopathy had a varied sensory and motor output response to heavy isometric contractions. Using the recommended approach of heavy 45-s isometric contractions did not offer a meaningful acute benefit for sensory or motor output for subjects with Achilles tendinopathy. Based on this study, heavy 45-s isometric contractions cannot be recommended for immediate pain relief or improved motor output for patients with Achilles tendinopathy.

LEVEL OF EVIDENCE

IV, prospective cohort study.

Clinical Improvements Are Not Explained by Changes in Tendon Structure on Ultrasound Tissue Characterization After an Exercise Program for Patellar Tendinopathy

OBJECTIVES

The aim of this study was to investigate the effects of a 4-wk in-season exercise program of isometric or isotonic exercises on tendon structure and dimensions as quantified by ultrasound tissue characterization (UTC).

DESIGN

This was a randomized clinical trial. Volleyball and basketball players (16-31 yrs, n = 29) with clinically diagnosed patellar tendinopathy were randomized to a 4-wk isometric or isotonic exercise program. The programs were designed to decrease patellar tendon pain. A baseline and 4-wk UTC scan was used to evaluate change in tendon structure.

RESULTS

No significant change in tendon structure or dimensions on UTC was detected after the exercise program despite patellar tendinopathy symptoms improving. The percentage and mean cross-sectional area of aligned fibrillar structure (echo types I + II) (Z = -0.414, P = 0.679) as well as disorganized structure (echo types III + IV) (Z = -0.370, P = 0.711) did not change over the 4-wk exercise program. Change in tendon structure and dimensions on UTC did not differ significantly between the groups.

CONCLUSION

Structural properties and dimensions of the patellar tendon on UTC did not change after a 4-wk isometric or isotonic exercise program for athletes with patellar tendinopathy in-season, despite an improvement in symptoms. It seems that structural improvements are not required for a positive clinical outcome.

Reliability and methodology of quantitative assessment of harvested and unharvested patellar tendons of ACL injured athletes using ultrasound tissue characterization

Background

Ultrasound tissue characterization (UTC) imaging has been previously used to describe the characteristics of patellar and Achilles tendons. UTC imaging compares and correlates successive ultrasonographic transverse tendon images to calculate the distribution of four color-coded echo-types that represent different tendon tissue types. However, UTC has not been used to describe the characteristics of patellar tendons after anterior cruciate ligament reconstruction (ACLR). The aim of this cross-sectional study was to assess the intra and inter-rater reliability of the UTC in unharvested and harvested patellar tendons of patients undergoing ACLR.

Methods

Intra and inter-rater reliability of both UTC data collection and analysis were assessed. Ten harvested and twenty unharvested patellar tendons from eighteen participants were scanned twice by the same examiner. Eleven harvested and ten unharvested patellar tendons from sixteen participants were scanned and analyzed twice by two different examiners. Twenty harvested and nineteen unharvested patellar tendons from twenty-three participants were analyzed twice by two examiners.

Results

Quantification of the proportion of echo-types I, II, III and IV in the areas of interest: (1) patella apex, (2) proximal tendon, (3) mid tendon, (4) distal tendon, and overall tendon of harvested and unharvested patellar tendons all displayed excellent intra-rater reliability (ICC_2,1: 0.94 to 0.99), excellent inter-rater reliability for harvested and unharvested patellar tendon scanning and analysis (ICC_2,1: 0.89 to 0.98), and excellent inter-rater reliability for analysis (ICC_2,1: 0.95 to 0.99). Intra-rater reliability for the measure of volume was good (ICC_2,1: 0.69 harvested, 0.67 unharvested), whilst mixed results were observed for the measure of mid tendon thickness (ICC_2,1: 0.88 harvested, 0.57 unharvested). Inter-rater reliability for scanning and analysis was good for volume (ICC_2,1: 0.67) and excellent for thickness (ICC_2,1: 0.97), while the inter-rater reliability for analysis was fair to poor for volume (ICC_2,1: 0.59 harvested, 0.30 unharvested), and excellent to poor for mid tendon thickness (ICC_2,1: 0.85 harvested, 0.24 unharvested).

Conclusion

UTC imaging is a reliable tool to characterize the quality of most aspects of unharvested and harvested patellar tendons in subjects undergoing ACLR.

Stress Relaxation and Targeted Nutrition to Treat Patellar Tendinopathy

Patellar tendinopathy is one of the most common afflictions in jumping sports. This case study outlines the rehabilitation of a professional basketball player diagnosed by magnetic resonance imaging (MRI) with a central core patellar tendinopathy within the proximal enthesis. The player undertook a nutrition and strength-based rehabilitation program combining gelatin ingestion and heavy isometric loading of the patellar tendon designed to produce significant stress relaxation as part of their competition schedule and a whole-body training plan. On follow-up one and a half years into the program an independent orthopedic surgeon declared the tendon normal on MRI. Importantly, the improved MRI results were associated with a decrease in pain and improved performance. This case study provides evidence that a nutritional intervention combined with a rehabilitation program that uses stress relaxation can improve clinical outcomes in elite athletes.

Efficacy of heel lifts versus calf muscle eccentric exercise for mid-portion Achilles tendinopathy (the HEALTHY trial): study protocol for a randomised trial

Background

Mid-portion Achilles tendinopathy is a common musculoskeletal condition characterised by degeneration of the Achilles tendon, which causes pain and disability. Multiple non-surgical treatments have been advocated for this condition including calf muscle eccentric exercise and in-shoe heel lifts. Although adherence is challenging, there is evidence to suggest that calf muscle eccentric exercise is effective in decreasing pain and improving function in people with Achilles tendinopathy. Heel lifts reduce ankle joint dorsiflexion and Achilles tendon strain, however their efficacy in the management of Achilles tendinopathy is unclear. This article describes the design of a parallel-group randomised trial comparing the efficacy of heel lifts to calf muscle eccentric exercise for Achilles tendinopathy.

Methods

Ninety-two participants with Achilles tendinopathy will be randomised to one of two groups: (i) a heel lift group that will receive pre-fabricated 12 mm in-shoe heel lifts (Clearly Adjustable®), or (ii) an exercise group that will be advised to carry out a calf muscle eccentric exercise program (twice a day, 7 days a week, for 12 weeks). Outcome measures will be obtained at baseline, 2, 6 and 12 weeks; the primary endpoint for assessing efficacy being 12 weeks. The primary outcome measure will be the total score of the Victorian Institute of Sport Assessment - Achilles (VISA-A) questionnaire. Secondary outcome measures will include thickness and integrity of the Achilles tendon (using ultrasound tissue characterisation [UTC]), participant perception of treatment effect on pain and function (using the 7-point Patient Global Impression of Change scale), severity of pain at the Achilles tendon (using a 100 mm visual analogue scale) in the previous week, health status (using the EuroQol-5D-5L™ questionnaire), physical activity levels (using the 7-day Recall Physical Activity Questionnaire) and calf muscle function (using the standing heel rise test). Data will be analysed using the intention to treat principle.

Discussion

The HEALTHY trial (Heel lifts versus calf muscle eccentric Exercise for AchiLles TendinopatHY) is the first randomised trial to compare the efficacy of heel lifts to calf muscle eccentric exercise in reducing pain and improving function in people with Achilles tendinopathy. A pragmatically designed trial was developed to ensure that if the interventions are found to be effective, the findings can be readily implemented in clinical practice.

Trial registration

Australian New Zealand Clinical Trials Registry: ACTRN12617001225303. Registered on August 22nd, 2017.

Ultrasonography effectiveness of the vibration vs cryotherapy added to an eccentric exercise protocol in patients with chronic mid-portion Achilles tendinopathy: A randomised clinical trial

Tendinopathy is a very common disease in the general population as well as in athletes. The aim of the present study was to examine the tendon thickness and cross-sectional area (CSA) in subjects with chronic mid-portion Achilles tendinopathy (AT) who engaged in either an eccentric exercise (EE) programme with vibration training or an EE programme combined with cryotherapy. A sample of 61 patients with chronic mid-portion AT were recruited and divided into two groups: EE programme vibration training (n = 30) and EE programme combined with cryotherapy (n = 31). Three ultrasound assessments were performed: pre-intervention and at 4, and at 12 weeks. The comparison of thickness and CSA measures at baseline, 4, and 12 weeks showed a significant (P < 0.05) increase at 0, 2, 4, and 6 cm in maximal isometric contraction and at rest in subjects with chronic mid-portion AT. The EE vibration training resulted in a statistically significant CSA increase compared with the cryotherapy group in patients with chronic mid-portion AT.

Quadriceps tendinopathy: a review-part 1: epidemiology and diagnosis

Overuse injuries of the extensor mechanism of the knee are common in both athletes and non-athletes and usually occur during activities associated with repetitive loading, stress, and knee extension. Historically, they have been labeled as Jumper's knee due to the high prevalence seen in the athletic community. In many published reports, the name "patellar tendinopathy" is used to describe this disorder of the quadriceps tendon at the patellar insertion, and the names are often used interchangeably. Numerous reports have been published describing extensor mechanism injuries in athletes, but there is a paucity of studies that focus on quadriceps tendinopathy. In addition, there is no universally accepted classification system for tendon pathology. Therefore, we performed a comprehensive literature review of these studies. This review consists of 2 parts. In the first part we review: (I) epidemiology and (II) diagnosis of quadriceps tendinopathy in the athlete as well as the general population. In the second part we discuss: (I) classification; (II) prognosis; and (III) treatment results.

Classification of Tendon Matrix Change Using Ultrasound Imaging: A Systematic Review and Meta-analysis

Ultrasound imaging (US) is an accurate and reliable method used to diagnose tendinopathy. This systematic review was aimed at identifying common criteria and parameters used to diagnose tendinopathy, the methodological quality of studies and the predictive value of US. Nineteen studies met the inclusion criteria, with the Achilles, quadriceps and patella tendons being investigated. Overall, there was significant heterogeneity between the criteria used to diagnose tendinopathy utilising US. The methodological quality of included studies was "good." Additionally, meta-analysis revealed that US-identified abnormalities were predictive of future symptoms, and classification of tendinopathy using three US defined parameters indicated a higher relative risk of developing clinical tendinopathy compared with the use of two US-defined parameters. Further research into the development of a standardised US criterion that incorporates both clinical and US findings is required to allow for greater consistency in the diagnosis of tendinopathy.

Shear Wave Elastography Measures of the Achilles Tendon: Influence of Time of Day, Leg Dominance and the Impact of an Acute 30-Minute Bout of Running

The mechanical properties of human tendons are likely to be influenced by factors known to affect elastic structures, including patterns of loading and unloading during the day. However, the exact scale and relevance of these variables to tendon stiffness remains unclear. The aim of this study was to (1) measure Achilles tendon (AT) stiffness over the course of the day, (2) examine AT stiffness between dominant and non-dominant standing leg tendons and (3) assess the impact of previous activity on AT stiffness. To assess the impact of time of day and leg dominance, 15 healthy participants (6 females, 9 males; mean age 28 ± 4 year, mean VISA-A score 99.0 ± 1.2) had shear wave elastography (SWE) measures taken at 08:00 h, 12:30 h and 17:00 h on both dominant and non-dominant legs. To assess the impact of exercise, 24 tendons were analysed (7 females, 5 males; mean age 27 ± 4 year, mean VISA-A Score 99.1 ± 1.1) with participants randomly assigned to either a control (CONT) group or a running (RUN) group. The RUN group performed a 30-min run at a subjective intensity of 13–15 on rating of perceived exertion (RPE) scale and had SWE measures taken before, immediately after, 6 h 24 h, 48 h and 72 h following the run. There were no significant differences in AT stiffness over the course of a day or between dominant and non-dominant leg. Significant increases in AT stiffness were noted pre-post run (0.27 m/s, 2.95%, p = 0.037). Leg dominance does not affect SWE values from asymptomatic ATs or change throughout a day, but a 30-min run significantly increases AT stiffness. Leg dominance and timing of clinical appointments are unlikely to affect SWE results, however a prior bout of physical activity may cause changes within the AT resulting in a significantly different SWE measure. Clinicians and researchers should be cautious of interpreting SWE results if weight bearing exercise has been performed beforehand.

Quantifying proximal patellar tendon changes during adolescence in elite ballet dancers, a 2-year study

Patellar tendon pathology appears to develop in young athletes. It is not known how this tendon develops through adolescence. This longitudinal study investigated proximal patellar tendon development during the adolescent growth spurt in young ballet dancers and identified whether puberty (estimated by maturity offset) had an effect on tendon development. Fifty two dancers (32 female and 20 male dancers, ages 11-18 at baseline) had ultrasound images of their tendons every 6 months for 2 years. Changes in tendon size (anterior-posterior diameter) on grayscale images and echogenicity, as quantified using ultrasound tissue characterization, were recorded each time. Maturity offset was calculated used to estimate peak height velocity (adolescent growth spurt). Maturity offset did not affect effect tendon composition before peak height velocity; however, after participants passed peak height velocity, maturity offset increased the composition of stable echopattern (P < .05): a 4% differential increase in type I echopattern, indicative of normal tendon structure, and a decrease in type III echopattern (more disorganized echopattern) by 0.7% per year. Anterior-posterior thickness increased by 0.2 mm/y (P < .05) measured 2 cm below the patella. Following peak height velocity, the proximal patellar tendon attachment increased in thickness and demonstrated a more stable echopattern representative of aligned fibrillar structure. Future research is required to further understand this normal maturation and the factors that support this process, with the aim of reducing the development of patellar tendon pathology in the adolescent jumping athlete.

Ultrasound elastography and ultrasound tissue characterisation for tendon evaluation

Ultrasound elastography (UE) and ultrasound tissue characterisation (UTC) are two newer modes of ultrasound (US) which have begun to attract scientific interests as ways to improve tendon characterisation. These modes of US show early promise in improved diagnostic accuracy, prediction of at-risk tendons and prognostication capability beyond conventional grey-scale US. Here, we provide a review of the literature on UE and UTC for Achilles, patellar and rotator cuff tendons.

The translational potential of this article: The present literature indicates that UE and UTC could potentially increase the clinician's ability to accurately diagnose the extent of tendon pathology, including preclinical injury.