AB0863 RADIOGRAPHY VERSUS ULTRASONOGRAPHY – WHICH IMAGING MODALITY TELLS US MORE ABOUT PAIN SEVERITY IN KNEE OSTEOARTHRITIS?

Abstract

Background:Osteoarthritis (OA) is a leading cause of disability worldwide and pain is its cardinal symptom. Ranging from structural injuries to central sensitization, multifactorial mechanisms play an important role in pain perception in patients with knee OA (KOA) defining a discrepancy between pain and structural damage. Imaging modalities such as radiography and musculoskeletal ultrasonography may assess those structural findings and both are well embedded in routine clinical practice. However, their association with pain severity is poorly studied.Objectives:To evaluate the place of X-ray- and ultrasound-derived parameters of structural damage for pain perception in knee osteoarthritis patients.Methods:Sixty-four knees from 38 patients with KOA fulfilling the ACR criteria were assessed. The pain severity was evaluated in all knees by 100-millimeters (mm) visual analogue scale (VAS). Anteroposterior radiographs of the fully extended knees in an upright weight-bearing position were obtained and images were evaluated according to the Kellgren-Lawrence (KL) and OARSI atlas. All patients were investigated with a portable MyLab 25 Gold system equipped with an LA435 transducer (Esaote SpA, Genoa, Italy) by two experienced ultrasonographers. The presence or absence of synovial thickening, effusion in the suprapatellar bursa, and popliteal cyst were assessed. Medial meniscal extrusion and medial and lateral femoral cartilage thickness (medial and lateral) were measured in mm in full extension and flexion position, respectively. Femoral osteophytes were semi-quantitatively scored using a scale consisted of four grades (0-3).Results:The levels of pain differed significantly in the KL groups (p = .001) and in the groups classified according to the medial tibiofemoral compartment narrowing defined in line with the OARSI atlas (p = .005). The other knee osteoarthritis radiographic characteristics derived from the OARSI atlas did not correlate with the pain. From the assessed ultrasound parameters, medial meniscal extrusion and medial femoral cartilage showed a weak correlation with pain levels (r = .254, p = .043; r = -.265, p = 0.034, respectively). Nevertheless, in the multivariate analysis after adjusting for age and BMI, both variables did not reach significance for explaining the differences in VAS levels. No association between the presence of synovial effusion and popliteal cyst and pain severity was found.Conclusion:Plain radiography and ultrasonography reflect different structural changes in osteoarthritis that may play an important role in pain perception. Both imaging modalities can complement each other in order to improve the evaluation of the patient with KOA.Acknowledgments:NoneDisclosure of Interests:None declared