To evaluate potential radiographic predictors of hip osteoarthritis progression.
A prospective, longitudinal two-year study was conducted in patients meeting American College of Rheumatology criteria for hip osteoarthritis. Hip osteoarthritis progression was defined as a greater than 0.5-mm decrease in joint space width measured using a magnifying glass marked at intervals of 0.1 mm, at the site of maximum joint space narrowing, by a single investigator who was blinded to the chronological order of the radiographs. Radiographic parameters determined at study entry were as follows: presence of osteophytes, osteosclerosis, and subchondral cysts; femoral head migration (superolateral, superomedial, concentric); and severity (joint space width in mm, Kellgren and Lawrence grade, subjective evaluation of joint space narrowing).
In the 463 study patients, joint space width decreased from 2.2 +/- 0.8 at baseline to 1.7 +/- 1.0 mm after two years (P < 0.0001). Radiographic progression was seen in 148 patients (32%). Radiologic parameters predictive of disease progression in the multivariate analyses were as follows:
Our data suggest that a number of baseline radiological features including distribution of joint space loss, subchondral bone production, and severity of joint space loss are predictive of progression of hip osteoarthritis.