Ultrasonography findings in knee osteoarthritis: a prospective observational cross-sectional study of 100 Patients

Introduction: Worldwide, knee osteoarthritis (KOA) accounts for 2.2% of total years lived with disability. There is low correlation between joint tissue damage and pain intensity. Periarticular structures may be involved and cannot be identified in X-rays. Objectives: To describe the main ultrasonography (USG) changes in symptomatic patients with primary KOA; to correlate number of USG findings with KOA severity assessed by Kellgren and Lawrence (K&L) radiological scores, with pain intensity measured by a visual analogue scale (VAS) and with functioning scores assessed with Timed up and go test (TUG) and Western Ontario and McMaster Universities (WOMAC) questionnaire. Methods: 100 patients with primary symptomatic KOA were assessed with X-ray and USG. Quantitative and qualitative analyses were evaluated in a systematic manner. Results: The most frequent findings were joint effusion, pes anserinus bursitis, quadriceps tendon enthesopathy, popliteal cyst, iliotibial band tendinitis and patellar tendinitis. Pearson’s correlation analysis demonstrated a significant moderate positive association between VAS scores and number of USG findings (r=0.36; p<0.0001). The number of USG findings was different between K&L grades I and III (p=0.041), I and IV (p<0.001), and II and IV (p=0.001, ANOVA with Bonferroni correction). There was significant association between number of USG findings and TUG (r=0.18; p=0.014) and WOMAC scores for pain (r=0.16; p<0.029) and physical function domains (r=0.16; p<0.028). Conclusion: The most frequent USG finding was joint effusion. Periarticular structures should be explored as potential sources of pain and disability