Objective. Magnetic resonance imaging (MRI) and radiography are established imaging modalities for the assessment of knee osteoarthritis (OA). The objective of our study was to compare the responsiveness of radiographic joint space width (JSW) with MRI-derived measures of cartilage morphometry for OA progression in participants from the Osteoarthritis Initiative (OAI). Methods. This study examined the baseline and 12-month visits of a subset of 150 subjects from the OAI. Measurement of radiographic JSW was facilitated by the use of automated software that delineated the femoral and tibial margins of the joint. Measures of medial compartment minimum JSW and JSW at fixed locations were compared with cartilage morphometry measures derived from MRI. The results were stratified by Kellgren/Lawrence (K/L) scale grade and by tibiofemoral anatomic axis angle. In order to examine the relative responsiveness of various techniques, we calculated the standardized response mean (SRM) between the 2 visits. Results. The SRM for radiographic JSW measured at the optimal location was ؊0.32 compared with ؊0.39 for the most responsive MRI measure. For the subgroup with a K/L scale grade of 2 or 3, the most responsive SRM values were ؊0.34 for radiographic JSW and ؊0.42 for MRI. Conclusion. Our study demonstrates that new measures using a software analysis of digital knee radiographic images are comparable with MRI in detecting OA progression, and potentially superior when considering the cost-effectiveness of the 2 imaging modalities.

Summary Objective To establish the performance of location specific computer measures of radiographic joint space width (JSW) compared to measurements of minimum joint space width (mJSW) for the assessment of medial compartment knee osteoarthritis (OA). The study also investigated the most disease-responsive location for measuring medial compartment JSW. Methods Serial bilateral Posterior Anterior (PA) conventional radiographs acquired with a fixed flexion protocol were obtained 36 months apart in 118 persons with knee OA participating in the Health, Aging and Body Composition (Health ABC) Study. Measurements of medial compartment mJSW and JSW at seven fixed locations were facilitated by the use of semi-automated software that delineated the femoral and tibial margins of the joint. A human reader operated custom software to verify and correct the software-drawn margins where necessary. Paired images were displayed with the reader blinded to the chronological order. The amount of joint space narrowing was measured and the standardized response mean (SRM) was used as a metric to quantify performance. Results For all subjects, the mJSW SRM value was 0.42 while, for the most responsive location specific measure of JSW, it was SRM = 0.46. For subjects with a Kellgren–Lawrence (KL) score less than or equal to 1, mJSW (SRM = 0.40) was more responsive than the new measures (Maximum SRM = 0.30). For KL = 2 or 3, SRM = 0.49 for mJSW, and SRM = 0.74 for the most responsive location specific measure of JSW. Improved responsiveness was observed in the more central portion of the joint on the more diseased knees. Conclusions Location specific computer measures of JSW are feasible and potentially provide a superior method to assess radiographic OA for more diseased subjects. This new measure has the potential to improve the power of clinical studies that use a fixed flexion protocol.

Labral tears and cartilage loss are common in patients with mechanical symptoms in the hip. Cartilage loss, labral tears and BME appear interrelated and may represent important risk factors that may affect the development and progression of osteoarthritis in the hip joint.