| Background:Enthesitis is a hallmark of ankylosing spondylitis(AS),while entheseal involvement in AS is not always detected by clinical examination.Ultrasound(US)has proved to be a highly sensitive and non-invasive tool especially for detecting and assessing entheseal abnormalities.Objectives:The aim of this study was to compare clinical examination with power Doppler US(PDUS)in the detection of entheseal abnormalities in patients with AS,to examine associations between PDUS assessments of enthesitis and traditional assessments of disease activity,and to examine sensitivity to changes of US assessment as well as traditional clinical variables during treatment with a biological agent,and to further explore the early diagnostic and follow-up values of entheseal ultrasonography in AS.Methods:Patients with AS initiating Enbrel treatment(50mg once a week)underwent clinical and PDUS examination at baseline and after 1,2,and 3 months.The following bilateral entheseal sites were examined:common extensor tendon at its insertion at the lateral humeral epicondyle;gluteus tendons at their insertion at the greater trochanter;quadriceps tendon at its insertion at the superior pole of the patella;patellar tendon at its proximal insertion at the inferior pole of the patella;patellar tendon at its distal insertion at the tibial tuberosity;Achilles tendon at its insertion at the calcaneus;and plantar aponeuroses at its insertion at the calcaneus.Clinical enthesopathy was defined by the presence of at least one of the following findings:spontaneous pain,tenderness elicited by pressure,and local swelling of the entheses.Using Phillips IU22,sonographic examination was performed at the same entheseal sites clinically evaluated.The laboratory tests included erythrocyte sedimentation rate(ESR)and C-reactive protein(CRP).The Bath Ankylosing Spondylitis Disease Activity Index(BASDAI)and visual analogue scale(VAS)of patient and physician were recorded.Correlations were analyzed by Spearman’s rank correlations.A Wilcoxon signed rank test was used to examine changes in US,clinical or laboratory assessments during follow-up.A P value<0.05 was considered significant.Results:Twenty AS patients were enrolled.Age was(25.2±9.6)years,disease duration was(4.3 ±3.1)years.Clinical and PDUS examination revealed at least one abnormal entheses in 9(45%)and 19(95%)AS patients,respectively.Furthermore,of 240 entheses examined in our 20 AS patients,47(19.6%)were considered abnormal by clinical examination and 123(51.3%)by PDUS.US abnormalities most commonly found were calcifications(33.3%),hypoechogenicity(29.2%),PD(25.8%),thickening(22.1%),bone irregularity(12.9%),erosions(9.6%)and bursitis(7.1%).44.7%of positive entheseal sites by clinical examination did not show any PDUS changes.On the other hand,51.3%of negative entheseal sites by clinical examination were considered abnormal by PDUS.Taking PDUS as the gold standard,clinical examination showed a low sensibility for the PDUS presence of entheseal abnormalities with vascularization(16%)and entheseal abnormalities without vascularization(23%).The US assessments were partially associated with clinical and laboratory variables of disease activity.The patients improved across all variables during follow-up and US assessments were highly sensitive to changes during treatment with biological agents.The improvement of US score continued during 2-3 month,although patients were basically in remission.Conclusions:PDUS permits detection of structural and inflammatory abnormalities of the entheses in AS,but there is still a considerable discrepancy between clinical and US findings.PDUS may complement the physical examination in order to better evaluate enthesitis.PDUS could be useful for assessment of AS activity and guiding the clinical medications. |
