The diagnostic performance of musculoskeletal ultrasound in gout: A systematic review and meta-analysis

<div><p>Background</p><p>Musculoskeletal ultrasound is widely used in diagnosing gout, but its accuracy is debatable. We conducted a systematic review and meta-analysis to quantitatively evaluate the value of ultrasound in the diagnosis of gout.</p><p>Methods</p><p>We systematically searched for publications using Cochrane Library, PubMed/Medline and Embase and manually screened the references of eligible articles for additional relevant publications. Studies were included in this systematic review if they assessed the diagnostic accuracy of ultrasound in gout compared to that of the gold standard, demonstration of monosodium urate crystals in joint fluid or tophi. We then conducted quantitative analyses by extracting data from each study and calculating the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR) and diagnostic odds ratio (DOR). The summary receiver operating characteristic curves (sROCs) were constructed to obtain the Q*-index and the area under the curve (AUC).</p><p>Results</p><p>Thirteen studies were included in this meta-analysis. The diagnostic performances of three distinctive ultrasonographic features of gout, double contour sign (DCS), the presence of tophi and the snowstorm sign, were evaluated. For person-based evaluations, the pooled sensitivity, specificity, DOR, AUC and Q* were as follows: for the DCS, 66% (95% confidence interval (CI) 62%-69%), 92% (95% CI 90%-94%), 25.91 (95% CI 11.80–56.89), 0.8163 and 0.7503, respectively; for the presence of tophi, 56% (95% CI 52%-60%), 94% (95% CI 92%-96%), 21.11 (95% CI 7.84–56.89), 0.8928 and 0.8236, respectively; for the snowstorm sign, 31% (95% CI 27%-36%), 91% (95% CI 88%-93%), 4.54(95% CI 3.13–6.58), 0.5946 and 0.5712, respectively; and for simultaneous consideration of these ultrasonographic features, 80% (95% CI 76%-83%), 83% (95% CI 79%-86%), 19.03 (95% CI 13.97–25.93), 0.889 and 0.8197, respectively. For the joint-/location-based evaluations, the pooled sensitivity, specificity, DOR, AUC and Q* were as follows: for the DCS, 75% (95% CI 68%-80%), 65% (95% CI 59%-70%), 16.90 (95% CI 5.10–56.03), 0.871 and 0.8014, respectively; and for the presence of tophi, 48% (95% CI 40%-57%), 96% (95% CI 91%-99%), 30.20 (95% CI 9.23–98.87), 0.8776 and 0.8081, respectively.</p><p>Conclusions</p><p>In this meta-analysis, relatively high specificity but modest or low sensitivity were demonstrated in the diagnosis of gout using each of the three ultrasonographic features for person-based evaluations. Simultaneous consideration of these ultrasound findings may improve the diagnostic sensitivity. However, the double contour sign alone is weak in the differentiation of gout and non-gout for joint-/location-based evaluations. Further well-designed studies are still needed to support the current findings.</p></div

Characteristics of included studies.

<p>Characteristics of included studies.</p

Patient summary.

<p>Patient summary.</p

A flow chart summarizing the study selection process for this meta-analysis.

<p>A flow chart summarizing the study selection process for this meta-analysis.</p

Clinical efficacy between the patients with and without BMP₂.

<p>Note: * P<0.05 The statistical value was derived from chi-square test (no statistical value can be obtained from the Fisher's exact test); P<0.05 between IIb and IIc as well as IIc and IIIa; statistical difference was also found between Type L1 and Type L3, and there were significant statistical differences between pre-and post-operation Harris score, but no statistical differences between IBG+BMP2 and IBG groups.</p

Schematic diagram of “Light Bulb procedure”: An approximate 1.5 cm×1.5 cm bone window was made at the femoral head–neck junction using osteotomes.

<p>And the necrotized bone located at anterolateral and upper side of the operated femoral head was alternately debrided using a high-speed drill. Then the cavity was filled with an autologous cancellous bone combination of rhBMP-2.</p

Kaplan–Meier survival curve shows that patients aged 40 and above had worse postoperative prognosis than patients aged under 40.

<p>Kaplan–Meier survival curve shows that patients aged 40 and above had worse postoperative prognosis than patients aged under 40.</p

Multivariate cox regression analysis results.

<p>Multivariate cox regression analysis results.</p

Subgroup analyses of diagnostic accuracy of ultrasound for gout.

<p>Subgroup analyses of diagnostic accuracy of ultrasound for gout.</p

Radiographs of a 46-year-old patient with osteonecrosis of the femoral head of the right side.

<p>A) and B) Serial AP and frog lateral radiographs showing ONFH ARCO stage IIIa/CJFH type L2 on the right sides. Subchondral insufficiency fracture can be clearly observed on the frog lateral radiographs. C) and D) Preoperative magnetic resonance image shows that the necrotic lesions involve the lateral pillar. E) and F) Serial AP and frog lateral radiographs taken eight months post operation show a progressive collapse of the femoral head.</p