Summary

The quality and difficulty of life of patients with early knee osteoarthritis (KOA) may be influenced by synovial hyperplasia in the suprapatellar bursa, joint effusion, and medial meniscus extrusion (MME) values in the upright position. Among them, synovial hyperplasia of the suprapatellar bursa and the amount of MME in the upright position were independently associated with the KOOS subscale.

Abstract

Introduction

In recent years, the importance of preventing the progression of knee osteoarthritis (KOA) has been advocated, and the concept of "early KOA" has attracted attention. Because this concept is relatively new, there is currently insufficient research on early KOA. This study aimed to characterize the ultrasonographic findings of patients with early KOA and determine which ultrasonographic findings were strongly associated with the KOOS subscale.

Methods

The study included 98 knees (98 patients: 35 men, 63 women, 60.3 ± 11.5 years old) with radiographically diagnosed Kellgren-Lawrence classification (K-L) grade 0 or 1 and early KOA, with pain and tenderness during activity 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 (MCL) bursa, infrapatellar fat pad, MM extrusion (MME) in the supine and upright positions, and the amount of change in MME were observed using ultrasonography. At the same time, we also instructed them to respond to KOOS.

Results

The percentages of patients with early KOA with synovial hyperplasia identified in the suprapatellar bursa, joint effusion, horizontal MM tears, osteophytes of the medial condyle of the femur, and osteophytes of the medial condyle of the tibia observed medially in the knee, were 9.2%, 38.8%, 60.2%, 48.0%, and 61.2%, respectively. In addition, 30.6%, 45.9%, and 24.5% of the patients had increased mild blood flow signals associated with synovial hyperplasia, MCL bursa, and infrapatellar fat pad, respectively. The mean MME was 2.69 mm in the supine position and 3.12 mm in the upright position. This showed that the MME of patients with early OA increased by approximately 0.4 mm when they were in the upright position. Correlations (p < .05) were found between the presence of synovial hyperplasia of the suprapatellar bursa (r < -.20) and the amount of MME in the upright position (r < -.24) and all five KOOS subscales. A significant correlation (p < .05) was found between the presence of joint effusion and the four KOOS subscales except QOL. Partial correlation coefficients showed significant correlations (p < .05) between knee joint effusion and symptoms (r = 0.299) and ADL (r = 0.254) of the KOOS subscale, and between MME in the upright position and Symptoms (r = -.263), Pain (r = -.256) and ADL (r = -.212).

Conclusion

The 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, synovial hyperplasia of the suprapatellar bursa and the amount of MME in the upright position were independently associated with the KOOS subscale. However, these relationships are weak, which may mean that the relationship between US findings and difficulties in daily living in patients with early KOA is associated with complex factors that were not examined in this study.