Relationship between ultrasonographic findings and subscales of the Knee Injury and Osteoarthritis Outcome Score in patients with early knee osteoarthritis: a multicenter study

To characterize the ultrasonographic findings of patients with early knee osteoarthritis (KOA) and determine which findings were associated with the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale.

The study included 98 knees (35 men, 63 women, 60.3 ± 11.5 years) diagnosed with early KOA with no major deformity radiographically, but with pain during activity and tenderness in the medial knee. Synovial hyperplasia in the suprapatellar bursa, knee joint effusion, horizontal tear of the medial meniscus (MM), osteophytes of the medial condyle of the femur and tibia, blood flow signals in the synovium of the suprapatellar bursa, medial collateral ligament bursa, infrapatellar fat pad, MM extrusion (MME) in the supine and upright positions, and the amount of change in MME were observed using ultrasonography.

Correlations (p < 0.05) were found between the presence of synovial hyperplasia of the suprapatellar bursa (r<-0.20) and amount of MME in the upright position (r< − 0.24) and all KOOS subscales. Presence of joint effusion and the four KOOS subscales except quality of life (QOL) were correlated (p < 0.05). Partial correlation coefficients showed correlations (p < 0.05) between knee joint effusion and symptoms (r = 0.299) and activities of daily living (ADL) (r = 0.254) of the KOOS subscales, and between MME in the upright position and symptoms (r= − 0.263), pain (r= − 0.256), and ADL (r= − 0.212).

Quality and difficulty of life of patients with early KOA may be influenced by synovial hyperplasia in the suprapatellar bursa, joint effusion, and MME values in the upright position. Among them, knee joint effusion and amount of MME in the upright position were independently associated with the KOOS subscales.