Abstract
Background. Although joint space width on weight-bearing radiographs of the knee is critical for early diagnosis and grading
knee osteoarthritis, the optimal method with which to accurately measure this value remains controversial. The purpose of this
study was to investigate and quantify the effects of the radiographic technique on joint space width in medial knee osteoarthritis.
Materials and Methods. We compared maximum plateau gaps and minimum joint space widths on bilateral weight-bearing
plain radiographs acquired using three different methods in 31 patients with medial knee osteoarthritis (56 knee joints): stand-ing with the knee extended (standard imaging); SynaFlexer method; and Rosenberg method. Measured values were com-pared statistically, with values of P <0.05 considered significant.
Results. Maximum plateau gap in the medial compartment was significantly lower with the SynaFlexer method (3.2 ± 1.5 mm)
and Rosenberg method (2.2 ± 1.2 mm) than with standard imaging (4.7 ± 2.2 mm; P <0.05 each). Minimum width of the me-dial joint space was also significantly lower with the SynaFlexer method (3.1 ± 1.4 mm) and Rosenberg method (2.3 ± 1.4 mm)
than with standard imaging (4.1 ± 1.4 mm; P <0.05 each).
Conclusion. The Rosenberg method appears beneficial for diagnosing early knee osteoarthritis, while the SynaFlexer meth-od seems more appropriate for assessing disease severity or progression in patients with painful intermediate to severe knee
osteoarthritis.
