Explaining Variability in the Prevalence of Achilles Tendon Abnormalities: A Systematic Review With Meta-analysis of Imaging Studies in Asymptomatic Individuals

Nonlinear Interactions of Lower Limb Clinical Measures Associated With Asymptomatic Achilles Tendon Abnormality in Ballet Dancers

CONTEXT

Tendon abnormalities on imaging are commonly observed in individuals with Achilles tendinopathy. Those abnormalities can also be present in asymptomatic individuals, which is an important risk factor for developing tendon symptoms. Ballet dancers are particularly vulnerable due to the high loads placed on their Achilles tendons. Understanding the relationship between clinical measures and tendon abnormality is essential for this population.

OBJECTIVE

To investigate the predictive value of clinical measures for identifying Achilles tendon abnormality in asymptomatic ballet dancers using a nonlinear statistical analysis.

DESIGN

Cross-sectional study.

SETTING

Dance company facility and research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Thirty-five asymptomatic professional and amateur ballet dancers enrolled (23 female/12 male).

MAIN OUTCOME MEASURE(S)

The presence of Achilles tendon abnormality was investigated using gray-scale ultrasound. Tendons were classified as having an abnormality if presenting with fusiform shape and/or hypoechoic areas. Clinical measures assessed were foot pronation; ankle dorsiflexion angle; hip, knee, and ankle isometric torque; and standing calf endurance. Classification and regression tree analysis was used to explore nonlinear interactions among clinical measures and their role in identifying tendon abnormality.

RESULTS

Sixty-eight tendons were included in the analysis. Structural change was common in asymptomatic dancers, with 80% presenting with tendon abnormality. Hip isometric torque, ankle dorsiflexion range of motion, and calf endurance were measures related to tendon abnormality. Interactions between hip torque and ankle dorsiflexion range of motion were statistically associated with the presence of tendon abnormality. Increased hip abductor torque was linked to a 59% reduction in the probability of tendon abnormality. The classification and regression tree model reached proper accuracy (total classification percentage of 83.8%).

CONCLUSIONS

Hip torque was an important clinical measure related to tendon structure. Assessment of dancers should include the whole lower limb as the combination of hip torque and ankle dorsiflexion range of motion accurately identified the presence of tendon abnormality.

Ultrasound as a predictor of time-loss injury for the patellar tendon, Achilles tendon and plantar fascia in division I collegiate athletes

OBJECTIVES

Tendinopathy and fasciopathy are common conditions that can result in time-loss injury in athletes. This study aimed to determine if preseason sonographic abnormalities of the patellar tendon, Achilles tendon and plantar fascia are associated with future time-loss injuries in collegiate athletes.

METHODS

National Collegiate Athletic Association Division I athletes from three institutions participated in this 3-year prospective, observational study. Each athlete completed a questionnaire, self-reporting current and prior symptoms and underwent an ultrasound examination of bilateral patellar tendons, Achilles tendons and plantar fasciae during annual preseason examinations. Ultrasound evaluations assessed for tendon and fascia thickening, hypoechogenicity and neovascularisation. Athletes were monitored for time-loss injury over the subsequent year.

RESULTS

A total of 695 athletes across 18 sporting disciplines (61.1% female, age 20.0±1.6, body mass index 23.1±2.9 kg/m2) were analysed over 3 years. Sonographic abnormalities were identified in 36.6%, 7.5% and 2.8% of the patellar tendons, Achilles tendons and plantar fasciae, respectively. Injuries were reported in 3.3%, 1.6% and 0.7% of these structures with an adjusted relative risk of injury increased by 8.9 (95% CI 3.7, 21.4), 18.8 (95% CI 7.2, 48.8) and 21.0 (95% CI 6.4, 68.1) times in those with preseason ultrasound abnormalities (p<0.001). The presence of an ultrasound abnormality was more predictive of future injury than self-report of a prior injury or pain in the area at the time of the scan.

CONCLUSION

Preseason sonographic abnormalities of the patellar tendon, Achilles tendon or plantar fascia are associated with a higher risk of developing time-loss injuries in collegiate athletes.

Sonographic Assessment of Asymptomatic Patellar and Achilles Tendons to Predict Future Pain: A Systematic Review and Meta-analysis

OBJECTIVE

Patients with clinical tendinopathy often demonstrate significant abnormalities with ultrasound (US) imaging. Tendon abnormalities likely precede pain in these patients. The purpose of this review was to systematically evaluate the available literature regarding the utility of US imaging as a method to predict Achilles and patellar tendon pain.

DESIGN

Systematic review and meta-analysis. Inclusion criteria were as follows: prospective studies of Achilles and patellar tendon pain development with baseline US measurements, follow-up clinical measurements, and English-language studies published after 2000. Exclusion criteria were prior rupture or surgery and presence of rheumatologic disorder.

SETTING

N/A.

PATIENTS

Athletes without Achilles or patellar tendon pain at baseline.

INTERVENTIONS

N/A.

MAIN OUTCOME MEASURES

Risk ratios (RRs) were identified for the development of pain in those with Achilles or patellar tendon sonographic abnormalities.

RESULTS

This review of 16 studies included 810 Achilles and 1156 patellar tendons from a variety of sports and demonstrated that the RR for pain development from abnormal Patellar and Achilles tendons was 6.07 [95% confidence interval (CI), 2.88-12.81; P < 0.001] and 3.96 [95% CI, 2.21-7.09; P < 0.001], respectively. The positive and negative predictive values of an abnormal US finding were 27.2% and 92.0% for the Achilles tendon and 27.2% and 93.5% for the patellar tendon, respectively.

CONCLUSIONS

This systematic review and meta-analysis identified that the use of asymptomatic US scanning of the Achilles or patellar tendon has a low positive predictive value but a high negative predictive value for the future development of pain.

Prevalence of Sonographic Achilles Tendon, Patellar Tendon, and Plantar Fascia Abnormalities in Division I Collegiate Athletes From a Variety of Sports

OBJECTIVE

This study aimed to determine the prevalence of ultrasound abnormalities in the Achilles tendon, patellar tendon, and plantar fascia among a large cohort of collegiate student-athletes.

DESIGN

Observational cross-sectional study.

SETTING

Three Division I institutions.

PARTICIPANTS

243 student-athletes participated in this study. Exclusion criteria included those younger than 18 years or who underwent prior surgery/amputation of structures, including anterior cruciate ligament (ACL) surgeries with patellar tendon grafts.

INTERVENTIONS

Ultrasound examination of the Achilles tendon, patellar tendon, and plantar fascia of each leg was performed. An experienced sonographer reviewed each tendon video in a blinded manner, with a separate experienced sonographer separately reviewing to establish inter-rater reliability.

MAIN OUTCOME MEASURES

The primary outcome measured was the presence of any sonographic abnormality including hypoechogenicity, thickening, or neovascularity.

RESULTS

Ultrasound abnormalities were identified in 10.1%, 37.2%, and 3.9% of all Achilles tendons, patellar tendons, and plantar fasciae, respectively. Abnormalities were significantly associated with the presence of concurrent pain for all structures ( P < 0.01). Specifically, athletes with sonographic abnormalities were approximately 4 times [relative risk (RR) = 4.25; 95% confidence interval (CI), 2.05-8.84], 6 times (RR = 5.69; 95% CI, 2.31-14.00), and 5 times (RR = 5.17; 95% CI, 1.76-15.25) more likely to self-report pain in the Achilles tendon, patellar tendon, and plantar fascia, respectively.

CONCLUSIONS

This multi-institutional study completed at 3 Division I institutions is the largest study of its kind to identify the prevalence of sonographic abnormalities in the Achilles tendon, patellar tendon, and plantar fascia among collegiate student-athletes of various sports.

The Medical Burden of Obesity and Overweight in the US Military: Association of BMI with Clinically Diagnosed Medical Conditions in United States Military Service Members

BACKGROUND

A high BMI is associated with various medical conditions, notably type 2 diabetes, cardiovascular disease, and mental health disorders. In the US military, BMI increased linearly between 1975 and 2015.

OBJECTIVE

This cross-sectional study investigated the associations between BMI and a comprehensive range of clinically diagnosed medical conditions (CDMCs) in US military service members (SMs).

METHODS

A stratified random sample of SMs (n=26,177) completed an online questionnaire reporting their height, weight, and demographic/lifestyle characteristics. Medical conditions for 6 mo before questionnaire completion were obtained from a comprehensive military electronic medical surveillance system and grouped into 39 CDMCs covering both broad (largely systemic) and specific medical conditions. BMI was calculated as weight/height2 (kg/m2). The prevalence of CDMCs was compared among normal weight (<25.0 kg/m2), overweight (25.0-29.9 kg/m2), and obese (≥30 kg/m2) SMs.

RESULTS

After multivariable adjustment for demographic/lifestyle characteristics, higher BMI was associated with higher odds of a diagnosed medical condition in 30 of 39 CDMCs, with all 30 displaying dose-response relationships. The 5 major CDMCs with the largest odds ratios comparing obese to normal weight were endocrine/nutritional/metabolic diseases (OR=2.67, 95%CI=2.24-3.15), nervous system diseases (odds ratio [OR]=2.59, 95%CI=2.32-2.90), circulatory system diseases (OR=2.56, 95%CI=2.15-3.06), musculoskeletal system diseases (OR=1.92, 95%CI=1.76-2.09), and mental/behavioral disorders (OR=1.69, 95%CI=1.51-1.90). Compared with normal weight SMs, overweight or obese SMs had a higher number of CDMCs (1.8±1.9 vs. 2.0±2.0 and 2.5±2.3, mean ± standard deviation, respectively, P<0.01).

CONCLUSIONS

In a young, physically active population, higher BMI was associated with a host of medical conditions, even after adjustment for demographic/lifestyle characteristics. The US Department of Defense should improve nutrition education and modify other factors that contribute to overweight and obesity. This study demonstrates that the medical burden of obesity is substantial in overweight and obese SMs.

Proximal patellar tendon abnormalities on ultrasound can develop in male adolescent basketball players: A longitudinal study

INTRODUCTION

Adolescent patellar tendinopathy is reported but the pubertal-stage of onset of abnormal tendon structure has not been investigated with grayscale ultrasound.

AIMS

To investigate abnormal tendon structure using grayscale ultrasound and its association with pubertal-stage and pain.

METHODS

Forty-three male basketball players aged 13.7 years (SD 1.0) had patellar tendon ultrasound scans every 6 months for 2.5 years. Pubertal-stage (peak height velocity) was calculated using the Mirwauld equation. Tendon thickness, hypoechogenicity and pain during single leg decline squat (SLDS) were recorded. Tendons were classified: hypoechoic, normal or immature.

RESULTS

Two tendons were hypoechoic at baseline. Six developed hypoechogenicity over 2.5 years (eight tendons [9%], six participants [14%]), all in peri and post-PHV players. Twenty-six tendons (17 participants) were classified as immature during the study. Hypoechoic tendons were thicker (5.3 mm SD 1.2) than normal (3.9 mm SD 0.7) tendons (p < 0.001). There was no difference in the proportion of participants reporting pain during SLDS in the hypoechoic (N = 3) and normal (N = 11) groups (p = 0.33), or in hypoechoic tendon thickness between those reporting pain (6.5 mm, SD 1.7) or not (5.2 mm, SD 0.9, p = 0.17).

DISCUSSION

This study using grayscale ultrasound found that basketball players with hypoechogenicity were peri or post-PHV. Abnormal structure was not always associated with pain.

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.