Background A cross-sectional study has shown that ultrasound (US) is more sensitive than conventional radiography (CR) in detecting small osteophytes in joints with hand osteoarthritis (OA). Osteophytes can be seen prior to joint space narrowing (JSN), may be an early risk factor for OA progression, and is associated with pain. However, previous studies on the predictive value of osteophytes on disease progression and pain is limited in number, have shown inconsistent results, and none of these have included US.
Objectives To examine whether US-detected osteophytes in joints with concurrent normal CR and no joint tenderness at baseline could predict incident radiographic hand OA and joint tenderness five years later.
Methods We included 78 participants (71 women, mean (SD) age 67.8 (5.2) years) from the Oslo hand OA cohort with US examination at baseline, and CR and clinical examination (tenderness upon palpation) at baseline and 5-year follow-up. US was performed on the first carpometacarpal and the interphalangeal joints. The radiographs was scored according to the Kellgren-Lawrence (KL) scale and the OARSI atlas for osteophytes (0-3) and joint space narrowing (JSN; 0-3). Associations between baseline US-detected osteophytes (independent variable) and incident radiographic OA features five years later (dependent variables) were explored only in joints without radiographic OA (i.e. KL grade=0, no osteophytes and no JSN) at baseline by use of Generalized Estimating Equations, expressed as odds ratio (OR) with 95% confidence intervals (CI) and adjusted for age, sex, body mass index and follow-up time. In addition, in radiographic normal joints with no tenderness at baseline, we explored whether US-detected osteophytes could predict incident joint tenderness.
Results Mean (SD) follow-up time was 4.7 (0.4) years. At baseline, 1218/1643 (74.1%) of the total number of assessed joints had US-detected osteophytes. In total 301 joints were assessed as being normal on CR, of which 86 had concurrent osteophytes detected by US. Most of these osteophytes (79.1%) were small (score 1). US-detected osteophytes at baseline was a strong predictor for incident radiographic OA during follow-up (table). The strongest association was seen for incident JSN (OR=5.3, 95% CI 2.1-13.4). In addition, a significant association was found between US-detected osteophytes at baseline and the occurrence of tenderness by joint palpation at follow-up (OR=1.9, 95% CI 1.1-3.3).
Conclusions For the first time, we were able to show that US-detected osteophytes were a strong predictor for the development of radiographic OA as well as tenderness at joint level after 5-years follow-up. These results support the use of US as a promising tool for early detection of hand OA.
Disclosure of Interest None declared