Association of femorotibial cartilage degeneration on magnetic resonance imaging with joint space width narrowing on radiographic knee osteoarthritis: Data from the Osteoarthritis Initiative (OAI)

Objectives The objective of this review is to assess whether joint space width (JSW) narrowing seen on anteroposterior (AP) plain radiographs relates to cartilage degeneration seen on MRI sequences in knee osteoarthritis with neutral, valgus and varus alignments.

Methods We retrospectively reviewed 639 participants, aged 45 to 79 years, in the Osteoarthritis Initiative (OAI) study, who had symptomatic knees with Kellgren and Lawrence grade 2 to 4 at baseline. Clinical assessments of the knee and disease activity, radiographs and MRIs were carried out annually over a period of six years. AP radiographs and complete MR sequences of the knee were available for all participants. Hip-knee-angle on hip-knee-ankle standing radiographs between 3° and -3°, ≥3°, and ≤ -3°, was measured to categorize the participants in neutral, valgus and varus knees, respectively. Quantative measurements of minimum femorotibial JSW and JSW at fixed locations in femorotibial joint were determined from AP fixed-flexion knee radiographs (Fig. 1). The femorotibial compartment was divided into six femoral and ten tibial subregions, and measurements of cartilage volume, thickness, and percentage of area of subchondral bone denuded of cartilage (%) of each of these subregions in MRI sequences were documented (Fig. 2). Linear regression with adjustment (age, sex, body mass index, and Kellgren and Lawrence grade) and Pearson’s Chi-square test was used. We calculated Pearson’s correlation coefficient (r), odds ratios (OR) and 95 % confidence intervals (95 % CIs).

Results and Conclusion We studied 345 (54 %) neutral, 87 (13.7 %) valgus, and 207 (32.3 %) varus knees of subjects in the OAI cohort. Radiographic JSW narrowing was significantly associated with cartilage volume and thickness, in central medial femoral subregions (ccMF) in neutral knees (r=0.78, OR 2.33 [95 % CI 2.12-2.54] and r=0.8, OR 1.85 [95 % CI 1.71-1.99], respectively), in external lateral tibial subregion (eLT) in valgus knees (r=0.87, OR 3.71 [95 % CI 3.26-4.17] and r=0.86, OR 3.22 [95 % CI 2.82-3.63], respectively), and in external medial tibial subregion (eMT) in varus knees (r=0.78, OR 4.46 [95 % CI 3.96-4.96] and r=0.87, OR 2.68 [95 % CI 2.47-2.88], respectively). We found a significant negative correlation between radiographic JSW narrowing and % of area of subchondral bone denuded of cartilage in external lateral tibial subregion (eLT) in valgus knees (r=-0.65, p < 0.01) and in external medial tibial subregion (eMT) in varus knees (r=-0.77, p< 0.01). No statistically significant correlation was found in anterior and posterior subregions (p >0.01) (aMT, pMT, aLT or pLT).

Plain radiography can be potentially used for initial detection of cartilage degeneration as assessed by MRI in medial femoral subregions in neutral knees, in lateral tibial subregions in valgus knees, and in medial tibial subregions in varus knees.

Nevertheless, a predication of cartilage degeneration in anterior and posterior subregions using plain radiography cannot be made.

Stichwörter mri, cartilage degeneration, osteoarthritis, plain radiography, radiography, Kellgren and Lawrence, cartilage loss, valgus alignment, varus alignment, arthrose, Pearson, Odds radio

Publication History

Article published online:
15 October 2020