Synovial changes detected by ultrasound in people with knee osteoarthritis – a meta-analysis of observational studies

Abstract

SummaryObjectivesTo examine the prevalence of synovial effusion, synovial hypertrophy and positive Doppler signal (DS) detected by ultrasound (US) in people with knee osteoarthritis (OA) and/or knee pain compared to that in the general population.MethodA systematic literature search was undertaken in Medline, EMBASE, Allied and Complementary Medicine, PubMed Web of Science, and SCOPUS databases in May 2015. Frequencies of US abnormalities in people with knee OA/pain, in the general population or asymptomatic controls were pooled using the random effects model. Publication bias and heterogeneity between studies were examined.ResultsTwenty four studies in people with knee pain/OA and five studies of the general population or asymptomatic controls met the inclusion criteria. The pooled prevalence of US effusion, synovial hypertrophy and positive DS in people with knee OA/pain were 51.5% (95% CI 40.2 to 62.8), 41.5% (26.3–57.5) and 32.7% (8.34–63.24), respectively, which were higher than those in the general population or asymptomatic controls (19.9% (95%CI 7.8–35.3%), 14.5% (0–58.81), and 15.8 (3.08–35.36), respectively). People with knee OA (ACR criteria or radiographic OA) had greater prevalence of US abnormalities than people with knee pain (P = 0.037, P = 0.010 and P = 0.009, respectively).ConclusionsUS detected effusion, synovial hypertrophy and DS are more common in people with knee OA/pain, compared to the general population. These abnormalities relate more to presence of OA structural changes than to pain.

Association between ultrasound-detected synovitis and knee pain: a population-based case–control study with both cross-sectional and follow-up data

“…The association between synovial changes and KP in OA have been investigated previously. In our recent meta-analysis [ 42 ], seven out of 10 studies reported a positive association between KP and effusion and two out of six studies reported an association with synovial hypertrophy. However, most studies did not adjust for ROA.…”

Synovitis in osteoarthritis: current understanding with therapeutic implications

“…Although ultrasound cannot assess cartilage deep in the joint or intra-bone lesions, it is well suited to assess inflammatory changes. A large meta-analysis of ultrasound-detected synovial changes found that people with knee OA or knee pain had high prevalence of effusion, synovial hypertrophy and power Doppler signals (ranging from 33 to 52% of the knees), and that these measures correlated well with histological findings [ 27 ]. A large multicentre study using ultrasound in 600 people with symptomatic knee OA demonstrated synovial inflammation or effusion in 46% of the population, despite using a strict definition of synovial hypertrophy [ 28 ].…”

Thresholds of ultrasound synovial abnormalities for knee osteoarthritis – a cross sectional study in the general population

“…US detection of synovial effusion and synovial hypertrophy in knees is more sensitive than clinical examination 9 , 10 , correlates well with histological findings 11 , 12 and correlates well with MRI in visualising effusion 13 , 14 . However, evidence regarding “normal” values for effusion and hypertrophy in the general population is limited 15 . For example, the only study to provide reference values for effusion was based on a group of healthy volunteers aged 20–60 years old ( n = 102) 16 , which is a low age range for OA, and no population studies have reported normal values for synovial hypertrophy or prevalence of Power Doppler signal (PDS).…”