Normative ultrasound values for Achilles tendon thickness in the general population and patients with Achilles tendinopathy: A large international cross-sectional study

The objective of the study was to obtain adjusted ultrasonographic reference values of the Achilles tendon thickness (maximum anterior-posterior distance) in adults without (previous) Achilles tendinopathy (AT) and to compare these reference values with AT patients. Six hundred participants were consecutively included, comprising 500 asymptomatic individuals and 100 patients with clinically diagnosed chronic AT. The maximum tendon thickness was assessed using Ultrasound Tissue Characterization. A multiple quantile regression model was developed, incorporating covariates (personal characteristics) that were found to have a significant impact on the maximum anterior-posterior distance of the Achilles tendon. A 95% reference interval (RI) was derived (50th, 2.5th-97.5th percentile). In asymptomatic participants median (95% RI) tendon thickness was 4.9 (3.8-6.9) mm for the midportion region and 3.7 (2.8-4.8) mm for the insertional region. Age, height, body mass index, and sex had a significant correlation with maximum tendon thickness. Median tendon thickness for the midportion region was calculated with the normative equation -2.1 + AGE × 0.021 + HEIGHT × 0.032+ BMI × 0.028 + SEX × 0.05. For the insertional region, the normative equation was -0.34 + AGE × 0.010+ HEIGHT × 0.018 + BMI × 0.022 + SEX × -0.05. In the equations, SEX is defined as 0 for males and 1 for females. Mean (95% CI) difference in tendon thickness compared to AT patients was 2.7 mm (2.3-3.2, p < 0.001) for the midportion and 1.4 mm (1.1-1.7, p < 0.001) for the insertional region. Compared to the asymptomatic population 73/100 (73%) AT patients exhibited increased tendon thickening, with values exceeding the 95% RI. This study presents novel reference values for the thickness of midportion and insertional region of the Achilles tendon, which were adjusted for personal characteristics. Our novel web-based openly accessible calculator for determining normative Achilles tendon thickness (www.achillestendontool.com) will be a useful resource in the diagnostic process. Trial registration number: This trial is registered in the Netherlands Trial Register (NL9010).

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.

Standardized pain mapping for diagnosing Achilles tendinopathy

OBJECTIVES

To assess the level of agreement between patient-reported pain using a standardized pain map and the physician-determined clinical diagnosis of Achilles tendinopathy.

DESIGN

Cross-sectional study.

METHODS

Eligible patients were adults visiting a sports physician for symptoms in the Achilles tendon region. Patients completed a digital questionnaire and indicated one location on a pain map where they experienced their pain. The primary outcome measure was level of agreement (% and Kappa coefficient) between patient-reported pain on the pain map and the physician-determined clinical diagnosis (defined as localized pain associated with tendon-loading activities and pain on palpation with or without tendon thickening). The secondary outcome measure was the agreement between the location on the pain map (midportion/insertional region) with the clinical diagnosis of midportion/insertional Achilles tendinopathy.

RESULTS

110 patients (mean (SD) age 48 (13), 61% men) with pain in the Achilles region were included. In 102 (93%, Kappa = 0.86, CI 0.78-0.95) patients who indicated pain in the Achilles tendon region on the pain map, the clinical diagnosis of Achilles tendinopathy was made by the sports physician. 82% of the patients had the clinical diagnosis of tendinopathy in the specific region of the tendon they marked on the pain map (Kappa = 0.67, CI 0.54-0.79).

CONCLUSIONS

There is almost perfect agreement between patient-reported pain on a pain map and a physician-established clinical diagnosis of Achilles tendinopathy. There was substantial agreement between the localization of the pain that was selected by the patient and the diagnosis of insertional/midportion Achilles tendinopathy by the physician. This tool could potentially aid in adequate triage for specialized care and for researchers performing large epidemiological studies.

The socio-economic impact of running-related injuries: A large prospective cohort study

Objectives

To evaluate the impact of running‐related injuries (RRIs) on activities of daily living (ADL), work, healthcare utilization, and estimated costs.

Design

Prospective cohort study with data from a randomized controlled trial.

Methods

Adult recreational runners who registered for a running event (distances 5 to 42 km) were included in this study. Minimum follow‐up duration was 3 months (preparation, event participation, and post‐race period). Injuries were registered using a standardized definition. Primary outcome measure was a standardized 5‐item survey on limitations in ADL. The survey data were categorized to the number of injured runners with complete/moderate/no limitations. This outcome was expressed as the percentage of injured runners with any limitation (complete or moderate limitations amalgamated). Secondary outcomes were work absenteeism, the number of healthcare visits per injured runner, and estimated direct medical and indirect costs per participant and per RRI.

Results

1929 runners (mean [SD] age 41 [12] years, 53% men) were included in this study and 883 runners (46%) sustained a RRI during the course of the study. Injured runners reported the highest limitations (% with any limitation) of RRIs during the first week of injury on sports and leisure activities (70%) and transportation activities (23%). 39% of the injured runners visited a healthcare professional. Work absenteeism due to the RRI was reported in 5% of the injured runners. The total mean estimated costs were €74 per RRI and €35 per participant.

Conclusions

Injured runners are mainly limited in their transportation activities and during sports and leisure. While the estimated costs of RRIs are not high when expressed per participant, the absolute costs may be substantial due to the popularity of running.

Impact of chronic Achilles tendinopathy on health-related quality of life, work performance, healthcare utilisation and costs

Objectives

To evaluate the impact of Achilles tendinopathy (AT) on quality of life (QoL), work performance, healthcare utilisation and costs in adults with conservatively treated chronic midportion AT.

Methods

This cross-sectional survey-based study included 80 patients and took place in a sports medicine department of a large regional hospital in the Netherlands. Data were collected before any intervention was given. Primary outcome was the EuroQol questionnaire (EQ-5D). The EQ-5D expresses the percentage of moderate/major problems on the domains self-care, anxiety/depression, mobility, usual activities and pain/discomfort. Secondary outcomes were the number of previous healthcare visits, work performance during the period of symptoms and estimated annual direct medical and indirect costs per patient as a result of AT.

Results

All 80 patients completed the questionnaires. The EQ-5D scores were low for the domains self-care (1%) and anxiety/depression (20%), and high for the domains mobility (66%), usual activities (50%) and pain/discomfort (89%). Patients with AT mainly reported an impact on work productivity (38%). Work absenteeism due to AT was present in 9%. The total median (IQR) number of annual healthcare visits was 9 (3-11). The total mean (SD) estimated annual costs were €840 (1420) per patient with AT (mean (SD) US$991 (1675)).

Conclusions

This study shows the large impact of AT on QoL and work productivity. This study also provides new information about the socioeconomic impact of AT, which emphasises that this common and longstanding disease causes substantial costs. These findings stress the need for optimised treatment and improved preventive interventions for AT.

Trial registration number

NCT02996409.