Musculoskeletal ultrasonographic evaluation of lower limb enthesopathy in ankylosing spondylitis and Behcet’s disease : relation to clinical status and disease activity

Abstract EN

Using clinical and musculoskeletal ultrasonographic (MSUS) examination, we aimed to compare the frequency, pattern, and main sites of peripheral enthesopathies in the lower limbs of ankylosing spondylitis (AS) and Behçet’s disease (BD) patients, and to evaluate their relation with different clinical, laboratory, and functional parameters of both diseases.

Patients and methods Fifteen AS patients (group I) and 22 BD patients (group II) were examined clinically and by carrying out MSUS for enthesopathy at five entheseal sites of the lower limbs.

A control group of 20 apparently healthy male volunteers was also included.

An enthesopathy score was calculated for each patient according to the Glasgow ultrasound enthesitis scoring system (GUESS).

Disease activity was assessed using the Bath Ankylosing Spondylitis Disease Activity Index and the Behçet’s disease current activity form in both groups, respectively.

Results The GUESS score was significantly higher (P < 0.05) in group I than in group II (7.27 ± 3.88 vs.

4.68 ± 3.67).

In the two patients’ groups, tendon thickening was the most frequent finding detected.

Bone erosions and enthesophytes were significantly (P < 0.05) more frequent in group I than in group II.

The most commonly affected entheseal sites were the distal Achilles tendon, followed by the proximal plantar fascia.

In group I, the GUESS scores significantly correlated with the fatigue scores (P < 0.05), peripheral joint pain scores (P < 0.05), and Bath Ankylosing Spondylitis Functional Index scores (P < 0.05), whereas it showed insignificant correlations with patients’ ages (P > 0.05), disease duration (P > 0.05), spinal pain scores (P > 0.05), local tenderness scores (P > 0.05), morning stiffness score (P > 0.05), total Bath Ankylosing Spondylitis Disease Activity Index (P > 0.05), Bath AS metrology indices (P > 0.05), AS quality of life scores (P > 0.05), radiographic scores (P > 0.05), erythrocyte sedimentation rate (P > 0.05), and C-reactive protein levels (P > 0.05).

In group II, the mean GUESS score was significantly higher (P < 0.05) for BD patients with arthritis than for BD patients without arthritis, but it showed insignificant correlation (P > 0.05) with disease activity.

Conclusion Ultrasonographic changes at the entheseal sites of the lower limbs are prevalent in both AS and BD.

These changes are more frequently related to functional and articular involvement.

MSUS is more sensitive than clinical examination in detecting enthesopathies of the lower limbs in both AS and BD patients.