Knee Pain Examined under Musculoskeletal Ultrasonography: Experience from a Community-based Rheumatology Practice – A Cross-sectional Study

Background: Diagnostic musculoskeletal ultrasonogram (MSUS) in musculoskeletal pain practice has increased. MSUS helps delineate extra-and intra-articular structures that are not visible on X-ray. Objective: Explore knee pain under ultrasonogram in a primary care rheumatology (PCR) facility. Methods: This cross-sectional study was performed over six months (January 1 and June 30, 2021) to explore knee pain in a community-based PCR setting. A physician registered in musculoskeletal (RMSK) ultrasonogram examined all patients and documented data in a prefabricated questionnaire. Statistical Package for the Social Sciences (SPSS, 28.0.1.1) was used to analyze data. Quantitative and categorical variables were presented with frequency and percentage. The Mann-Whitney-U test assessed the correlation between categorical variables; p<0.05 was considered statistically significant. Results: A total of 118 knees of 92 patients were included. Following are MSUS-depicted structural changes: medial joint line osteophytes (91.3%), medial femoral condyle (MFC), cartilage echogenicity (78.3%), synovial plica (76%), knee effusion (61.9%), synovial membrane thickening (54.3%), increased medial collateral ligament (MCL) thickness (42.4), reduced trochlear and MFC thickness (36.9%), Baker's cyst (35.8%), increased MFC thickness (31.5%), medial meniscal extrusion (MME) (27.2%), synovial hypertrophy (20.6%), increased trochlear cartilage thickness (20.6%), MM tear (18.5%), semitendinosus (SMT) bursitis (6.5%), loose body (6.5%), frond-like synovial mass (5.4%), MCL calcification (4.3%) and MM cyst (4.3%). There was a statistically significant correlation between the following variables: Knee effusion and synovial plica; reduced MFC thickness; MME and reduced MFC thickness and moderate osteophyte. Conclusion: High-frequency diagnostic ultrasound can depict knee pathology precisely. MSUS at the primary healthcare facility can minimize patient referral and burden over the tertiary setting and reduce overall expenditure.