Abstract BACKGROUND AND AIMS Musculoskeletal disorders remain a major problem in haemodialysis (HD) patients. The aim of this study was to determine knee clinical and ultrasonographic (US) abnormalities in HD patients to evaluate the influence of age, gender and HD duration. METHOD This cross-sectional descriptive study was conducted on 52 patients (104 knee joints) who had been on regular HD for at least 6 months. Demographic, clinical, therapeutic and laboratory data were recruited. Participants were questioned about the presence of chronic knee pain and its duration, severity and laterality. Both knees were evaluated for the presence of joint swelling, crepitus and tenderness. All patients underwent musculoskeletal (MSUS) evaluation of both knees, which was conducted according to EULAR standardized procedures. MSUS was used to determine the presence of suprapatellar effusion, synovial thickening and Baker's cyst and to detect any abnormalities in the cartilage morphology. Quadriceps and patellar tendons and menisci were also sonographically assessed. Cartilage thickness was measured bilaterally from the central points of the medial condyle and lateral condyle patients were then compared according to age, gender and HD duration. RESULTS The mean age of the patients was 52.4 ± 14.15 years, 25 females and 27 males, and the median duration of HD was 3.5 (0.6–13) years. Chronic knee pain was present in 31/104 (29.8%) knees. Among the scanned 104 knee joints, there was at least one US abnormality in 91 (87.5%); suprapatellar effusion was found in 57 (54.8%), synovial thickening in 13 (12.5%), abnormal cartilage morphology in 68 (65.4%), quadriceps tendon abnormalities in 58 (55.8%), patellar tendon abnormalities in 34 (32.7), medial meniscus abnormalities in 30 (28.8%), lateral meniscus abnormalities in 13 (12.5%) and Baker’s cyst in 5 (4.8%) (Fig. 1). MSUS abnormalities were significantly more frequent in HD patients aged >40 years (94.9% versus 65.4; P = .000) than others. Chronic knee pain and abnormal cartilage morphology were more likely to occur in females (40% versus 20.4% and 74.1% versus 56%, respectively) than in males (Fig. 2). According to HD duration, quadriceps and patellar tendons showed more frequent US abnormalities in patients with HD duration > 3 years (86.5% versus 42% and 38.9% versus 26%, respectively) than in others. The prevalence of mild, moderate and severe suprapatellar effusion was 37.5%, 14.4% and 2.9%, respectively. There was a significant association between semiquantitative measurement of suprapatellar effusion and synovial thickening (P = .000), abnormal cartilage morphology (P = 0.023), quadriceps (0.002) and patellar tendon abnormalities (0.011) (Table 1). CONCLUSION Knee US abnormalities are prevalent among HD patients, especially those with female gender, older age and higher HD duration. These abnormalities may be subclinical. The severity of suprapatellar effusion is usually related to other knee structural abnormalities.