Purpose: The purpose was four-fold: to assess the reproducibility of p.a. weight-bearing radiograms of the knee and the minimal joint-space (MJS) width measurements in these radiograms; to compare the MJS with MR-detected cartilage defects; to evaluate the location of these cartilage defects; and to estimate the relation between meniscal abnormalities and joint-space narrowing.
Material and methods: Fifty-nine individuals, aged 41-58 years (mean 50), with chronic knee pain were examined by means of p.a. weight-bearing radiograms in semiflexion with fluoroscopic guidance of the knee joint. The MJS was measured with a standard ruler. On the same day MR imaging was performed with proton-density- and T2-weighted turbo spin-echo on a 1.0 T imager. Meniscal abnormalities and cartilage defects in the tibiofemoral joint (TFJ) were noted.
Results and conclusion: The p.a. view of the knee and the MJS measurements were reproducible. MJS of 3 mm is a limit in diagnosing joint-space narrowing in knees with MR-detected cartilage defects. There was a high proportion (p < 0.001) of meniscal abnormality within the narrowed compartments in comparison with those that were not narrowed. A larger number of the cartilage defects (p < 0.05) was found in the medial femoral condyle than in any of the other condyles of the TFJ. The defects had a dorsal location (p < 0.001) as shown in the weight-bearing radiograms of the knee in semiflexion.