A novel method for assessing proximal tibiofibular joint on MR images in patients with knee osteoarthritis

Objectives: To validate a method to measure the morphological parameters of the proximal tibiofibular joint (PTFJ) in patients with knee osteoarthritis (OA). Methods: 408 participants were examined in this cross-sectional subject-based study. We calculated the fibular contacting area of PTFJ (S) and its projection areas onto the horizontal plane (load-bearing area, S tau), the sagittal plane (lateral stress-bolstering area, S phi) and the coronal plane (posterior stress-bolstering area, S nu). Joint space narrowing (JSN) and osteophyte was measured using radiographs. Cartilage defects, bone marrow lesions (BMLs) and cartilage volume were evaluated using magnetic resonance imaging (MRI). Results: The average PTFJ fibular contacting area was 2.4 cm(2) (SD, +/- 0.7 cm(2)). Intra-observer and interobserver reliabilities of measures of PTFJ morphological parameters were excellent (>= 0.90). S, S tau and S phi were significantly associated with JSN in the medial tibiofemoral compartment (PR: 1.40, 95% CI 1.10-1.78; PR: 1.65, 95% CI 1.25-2.18 and PR: 0.53, 95% CI 0.29-0.97, respectively). There was a significantly positive association between S, S tau and medial and/or femoral tibial cartilage defects. S, S tau and S nu were significantly and positively associated with medial and/or femoral tibial BMLs (PR: 1.36, 95% CI 1.12-1.64; PR: 1.47, 95% CI 1.17-1.83; and PR: 1.39, 95% CI 1.06-1.82, respectively) after adjustment. S and S tau were significantly and negatively associated with medial tibial cartilage volume. Conclusions: This novel method to assess the morphological parameters of PTFJ in MRI is reproducible. These parameters are associated with knee radiographic and MRI-based OA-related structural abnormalities, suggesting clinical construct validity. Its predictive validity needs to be examined in future longitudinal studies. (c) 2018 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.