Which risk factors determine cartilage thickness and composition change in radiographically normal knees? - Data from the Osteoarthritis Initiative

Weaker subchondral bone and thinner articular cartilage of the knee are associated with elevated baseline fracture risk independently of osteoarthritis risk factors

Knee osteoarthritis involves damaged bones beneath joint surfaces but how current bone health predicts future disease state is unclear. We discovered higher osteoporotic fracture risk (FRAX) was linked to compromised knee bone quality and thinner cartilage. Integrating FRAX into osteoarthritis care could identify who may develop worse disease outcomes.

OBJECTIVES

To examine how well fracture risk predicts subchondral bone and cartilage morphometry independently of osteoarthritis (OA) clinical risk factors.

METHODS

Male and female participants in the Osteoarthritis Initiative (OAI) at visit 5 (36 months) were evaluated for fracture risk using FRAX and categorized into low-, moderate-, or high-risk groups. These groups were compared for bone marrow lesion (BML) size, number and effusion, subchondral bone structure, density, and cartilage morphometry in the most affected knee at either same time point, 1 or 2 years later, using general linear models. Sex interactions were examined in each case and probed if significant.

RESULTS

Among 1240 participants (58.8% female, age: 63.7 ± 8.8 years, and BMI: 30.1 ± 4.9 kg/m2), 20.32% had moderate or high FRAX and showed lower subchondral bone density (- 0.12 to - 0.25 g/cm2), less intact trabeculae, and thinner cartilage (- 0.14 to - 0.47 mm) compared to low FRAX (p < 0.05). Males showed larger positive FRAX correlations with bone density, and females had protective effects of FRAX against BML numbers, although the effects were small (sex interaction, p < 0.05). All FRAX models adjusting for OA risk factors yielded better model fit than OA risk factors alone. Having moderate/high versus low FRAX at baseline predicted a 1.36 (1.00, 1.86)-fold higher odds of reaching a Kellgren-Lawrence score of 3 or 4 within a year.

CONCLUSIONS

High FRAX predicts thinner cartilage and weaker subchondral bone within a year. Complementing standard OA clinical risk factors with FRAX calculation could help identify individuals likely to develop worse knee OA radiologic outcomes.

Ultrasound Imaging in Knee Osteoarthritis: Current Role, Recent Advancements, and Future Perspectives

While conventional radiography and MRI have a well-established role in the assessment of patients with knee osteoarthritis, ultrasound is considered a complementary and additional tool. Moreover, the actual usefulness of ultrasound is still a matter of debate in knee osteoarthritis assessment. Despite that, ultrasound offers several advantages and interesting aspects for both current clinical practice and future perspectives. Ultrasound is potentially a helpful tool in the detection of anomalies such as cartilage degradation, osteophytes, and synovitis in cases of knee osteoarthritis. Furthermore, local diagnostic and minimally invasive therapeutic operations pertaining to knee osteoarthritis can be safely guided by real-time ultrasound imaging. We are constantly observing a growing knowledge and awareness among radiologists and other physicians, concerning ultrasound imaging. Ultrasound studies can be extremely useful to track the response to various therapies. For this specific aim, tele-ultrasonography may constitute an easy tool aiding precise and repeated follow-up controls. Moreover, raw radio-frequency data from US backscattering signals contain more information than B-mode imaging. This paves the way for quantitative in-depth analyses of cartilage, bone, and other articular structures. Overall, ultrasound technologies and their rapid evolution have the potential to make a difference at both the research and clinical levels. This narrative review article describes the potential of such technologies and their possible future implications.

Imaging Biomarkers of Osteoarthritis

Currently no disease-modifying osteoarthritis drug has been approved for the treatment of osteoarthritis (OA) that can reverse, hold, or slow the progression of structural damage of OA-affected joints. The reasons for failure are manifold and include the heterogeneity of structural disease of the OA joint at trial inclusion, and the sensitivity of biomarkers used to measure a potential treatment effect.This article discusses the role and potential of different imaging biomarkers in OA research. We review the current role of radiography, as well as advances in quantitative three-dimensional morphological cartilage assessment and semiquantitative whole-organ assessment of OA. Although magnetic resonance imaging has evolved as the leading imaging method in OA research, recent developments in computed tomography are also discussed briefly. Finally, we address the experience from the Foundation for the National Institutes of Health Biomarker Consortium biomarker qualification study and the future role of artificial intelligence.