Associations between the morphological parameters of proximal tibiofibular joint (PTFJ) and changes in tibiofemoral joint structures in patients with knee osteoarthritis

BACKGROUND: To describe the longitudinal associations between the morphological parameters of proximal tibiofibular joint (PTFJ) and joint structural changes in tibiofemoral compartments in patients with knee osteoarthritis (OA). METHODS: The participants were selected from the Vitamin D Effects on Osteoarthritis (VIDEO) study. PTFJ morphological parameters were measured on coronal and sagittal MRI. The contacting area (S) of PTFJ and its projection areas onto the horizontal (load-bearing area, Sτ), sagittal (lateral stress-bolstering area, Sφ), and coronal plane (posterior stress-bolstering area, Sυ) were assessed. Knee structural abnormalities, including cartilage defects, bone marrow lesions (BMLs), and cartilage volume, were evaluated at baseline and after 2 years. Log binominal regression models and linear regression models were used to assess the associations between PTFJ morphological parameters and osteoarthritic structural changes. RESULTS: In the longitudinal analyses, the S (RR: 1.45) and Sτ (RR: 1.55) of PTFJ were significantly and positively associated with an increase in medial tibial (MT) cartilage defects. The Sτ (β: − 0.07), Sυ (β: − 0.07), and S (β: − 0.06) of PTFJ were significantly and negatively associated with changes in MT cartilage volume. The Sτ (RR: 1.55) of PTFJ was positively associated with an increase in MT BMLs, and Sφ (RR: 0.35) was negatively associated with an increase in medial femoral BMLs. CONCLUSIONS: This longitudinal study suggests that higher load-bearing area of PTFJ could be a risk factor for structural changes in medial tibiofemoral (MTF) compartment in knee OA. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT01176344 Anzctr.org.au Identifier: ACTRN12610000495022 Date of registration: 7 May 2010 SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13075-022-02719-8.