RESUMEN
Purpose: To investigate the performance of ultrasonography (US) for the detection of knee osteoarthritis (OA) in patients suffering from knee pain, compared to conventional radiographs. Methods: Cross-sectional study performed at a university teaching hospital. Consecutive patients complaining of unilateral or bilateral mechanical knee pain who signed an informed consent were included. All patients underwent simultaneously an ultrasonographic and a radiographic evaluation of the knee. Exclusion criteria were age under 18 years, prior diagnosis of knee OA, diagnosis of inflammatory arthritis, history of knee surgery or trauma, severe knee deformities, and corticosteroid injection within the last 2 months. The diagnostic properties of US for the detection of knee OA were evaluated using radiological data as the reference method. Evaluated test properties were sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the positive and negative likelihood ratio (LR+ and LR-). Results: Three-hundred twenty-two knees (281 patients) were included. Radiographic degenerative changes were present in 56.8% (183) of the evaluated knees. Regarding the diagnostic properties of the US, the presence of either osteophytes or the compromise of the femoral hyaline cartilage had the best sensitivity to detect OA (95%), with a NPV of 92% and a LR- of 0,07, while the combined identification of osteophytes and compromise of the femoral hyaline cartilage had the best specificity (94%), with 94% PPV and a LR+ of 13. Conclusion: US demonstrated an excellent sensitivity with an adequate specificity for the detection of radiographic knee OA.
RESUMEN
OBJECTIVE: A patient self-administered questionnaire [PsA Screening and Evaluation (PASE)] has been developed and validated in English, but has not been tried in Spanish speaking populations. This study aimed to adapt and validate PASE in Spanish to screen Spanish speaking psoriasis patients for signs and symptoms of inflammatory arthritis. METHODS: Initial translation from English to Spanish (forward translation) was performed by two independent translators and the resulting versions were synthesized during a consensus meeting. The questionnaire was tried in a pilot study and resulted in a change in the agreement scale for a frequency scale with wording adaptation [Spanish PASE (PASE-S)]. RESULTS: One hundred and eleven patients were screened with PASE-S; 25 with PsA (without previous treatments), 23 with psoriasis, 22 with psoriasis and OA and 41 with OA without psoriasis. The diagnosis of psoriasis was performed by a dermatologist, and a rheumatologist determined the diagnosis of PsA or OA. Patients with PsA had statistically significant higher symptoms, function and total PASE-S scores compared with those without PsA. Receiver operator curves showed an area under the curve of 0.79 (95% CI 0.69, 0.89) for the total score. A cut-off value ≥34 showed sensitivity of 76%, and specificity of 74.4% for the diagnosis of PsA. CONCLUSION: The validated PASE questionnaire is a self-administered tool that can be used to screen for PsA among patients with psoriasis in a Spanish speaking population. PASE was able to distinguish between symptoms of PsA and OA.