Background Ultrasound (US) examination of the entheses is increasingly used to document pathological changes in e.g. psoriasis arthritis and spondyloarthritis. Grey-scale (GS) US is used to assess morphological changes and Doppler US to assess increased blood flow.
The OMERACT expert group has agreed on the following elementary components when assessing the entheses on US examination; hypoechogenicity, increased thickness, enthesophytes/ calcifications, erosions, and Doppler activity (1).
Little is known about US assessment of the entheses in asymptomatic persons, thus the frequency and distribution of the above components between genders and age groups is uncertain.
Objectives To investigate the frequency of enthesitis components in the entheses of the lower limb in a group of healthy subjects.
Methods We recruited 64 subjects (32 women and 32 men), eight women and eight men in four decades, from 20 to 59 years. None of the subjects had previous or present signs of tendon or joint disease in the lower extremities. None of the participants took any kind of medication.
All subjects were examined by a rheumatologist and blood samples were collected to rule out any clinical signs of tendon or joint disease e.g. swollen and tender entheses or increased inflammatory markers in the blood. The dominant leg was examined with US using a Logiq 9 (GE Medical, Milwaukee, WI, USA) with a ML 6–15 MHz transducer and a fixed pre-set with Doppler settings optimised for inflammatory flow. Both GS and Doppler examination were made.
The entheses were examined for hypoechogenicity, increased thickness, enthesophytes/ calcifications, erosions, and Doppler activity.
Results No subjects had clinical signs of tendon or joint disease. Seven displayed various degrees of hypermobility and seven had various degrees of flatfoot; some in combination. None of the blood tests indicated any pathology.
On US erosions were only seen in one Achilles insertion (not shown in table). The Doppler activity was not measured in plantar fascia due to attenuation of the heel fad pad. All other US pathology present is seen in the table below.
Conclusions Only minor pathological findings in the entheses of the lower limb were present in an age stratified cohort of healthy persons. The changes most frequently seen were bony changes in the insertion of the quadriceps and Achilles tendons. A weak tendency toward more pathological findings was seen in this cohort among men, compared to women, and additionally, with increasing age.
The findings suggest that US can be used to diagnose/examine subjects for pathological changes of the entheses although with caution regarding enthesophytes of the quadriceps and Achilles tendon.
Terslev L et al. Defining enthesitis in spondyloarthritis by ultrasound: results of a Delphi process and of a reliability reading exercise. Arthritis Care Res 2014 May;66:741–8.
Disclosure of Interest None declared