Two world congresses within two weeks: Featuring novel endpoints of synovitis

Every April, a large part of the musculoskeletal research community gathers. What started more than two decades ago – as a focused meetings on osteoporosis – has evolved into today’s @World Congress on Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (WCO-IOF-ESCEO). The 2025 meeting in Rome gathered about 4000 onsite attendees, and about the same number of virtual participants.

The WCO-IOF-ESCEO conference represents a unique forum that brings together researchers, industry, and practicing clinicians across many disciplines. This evolution matters, because treating complex musculoskeletal diseases increasingly requires connecting transdisciplinary perspectives — from bone to cartilage, from imaging endpoints to clinical outcomes.

🧲 At this conference we touched new ground by developing and testing proxies of disease activity using non-contrast-enhanced MR imaging, specifically quantification of Effusion Synovitis (➡️ see carousel).

→  PLENARY LECTURE: Felix Eckstein
State of the art: advances in osteoarthritis imaging
Scientific Session VI – Saturday, April 18, 2026 at 15:00, Auditorium 1.

In this lecture, he summarized the current state of the art in osteoarthritis imaging—from patient selection and acquisition to AI-based analysis (DL, CNNs), monitoring structural treatment effects, clinical validation, and eventual qualification of novel biomarkers as surrogate endpoints. He focused on cartilage morphometry and relaxometry (composition – T2) as well as new approaches of Hoffa radiomics, for quantifying Hoffa synovitis.

→  POSTER (P889): Kowsar Sheikhi Valashani
QUANTITATIVE ASSESSMENT OF EFFUSION-SYNOVITIS IN KNEE OSTEOARTHRITIS AND COMPARISON WITH GOLD-STANDARD RADIOLOGICAL READINGS
Viewing Session II – Saturday April 18, 2026: 08:30 – 16:00 (attended 14:00 – 15:00)

As a new PhD at PMU and junior imaging scientist at Chondrometrics, Kowsar showed that fully automated AI-based measurement of effusion-synovitis volume (ESV) demonstrated high criterion validity, i.e. good correlation with manual segmentation, and strong construct and convergent validity, i.e. continuous ESV aligned well with semiquantitative MOAKS grades on DESS MRI, and reflected the underlying pathology in line with expert radiologist assessments.

→  ORAL COMMUNICATION: Felix Eckstein
IS EFFUSION SYNOVITIS, ASSESSED QUANTITATIVELY BY MORPHOMETRY OR SEMI-QUANTITATIVELY BY EXPERT READING; RELATED TO OSTEOARTHRITIS PROGRESSION
Scientific Sesssion VI – Saturday April 18, 2026 at 16:30, Auditorium 1.

Building on this, our CMO showed that ESV is not just descriptive—but predictive. Longitudinal ESV measurement demonstrated high “sensitivity to change” and strong predictive validity for disease progression. In the FNIH Biomarker Consortium study, ESV increased by ~40% over 2 years in participants with combined radiographic and symptomatic progression, while it decreased by ~10% in matched non-progressive controls (➡️ see carousel).

Thanks to PROTO Horizon (T. Winkler) and Ludwig Boltzmann Institute Arthritis and Rehabilitation LBIAR 1(T. Stamm) for their support in our quantitative synovitis imaging biomarker development. And to our co-authors: Jamie Collins , Frank Roemer, Ali Guermazi and David Hunter.

Only three days later, the OARSI – Osteoarthritis Research Society International – World Congress on Osteoarthritis was kicked off in Palm Springs Florida, and although we did not participate personally, we were grateful for our collaborators to present on our behalf or with us a co-authors. The idea behind the work from ESCEO was extended to “Hoffa radiomics”. Different methods — same goal: make inflammation scalable and measurable on a continuous scale, to explore its sensitivity and its clinical relevance.

Radiomics quantitatively assesses complex distributions of (MRI) signal and texture. The Hoffa (infrapateallar fat pad) is an adipose tissue structure located within the joint capsule, but just outside the synovial membrane. In the absence of contrast enhancement, MRI signal change is graded on a “Hoffa synovitis (HS) scale of 0-3 by expert readers, using the MOAKS system. Quantitative measurement of HS – based on AI-based segmentation – is fast, makes the evaluation scalable to large cohorts, and is potentially more sensitive to small increments of longitudinal change.

→ In a podium presentation, Wolfgang Wirth as first and Frank Roemer as presenting author talked about the criterion validity of CNN-based vs. manual Hoffa segmentation, and on it’s construct validity: As for ESV, continuous Hoffa radiomic measures aligned well with sq MOAKS grades and reflected the underlying pathology, in line with expert readings (➡️ carousel).

→ In a poster, Felix Eckstein showed that baseline Hoffa radiomics was at least as predictive of disease progression over 2-5 years in the FNIH OA Biomarker Consortium Cohort as MOAKS Hoffa Synovitis, with the greatest differences noted in the posterior Hoffa (➡️ carousel).

Great thanks again to PROTO and the LBIAR for support, and to our co-authors: Frank Roemer, Jamie Collins, Ali Guermazi, David Hunter, Tobias Winkler.

In further contributions that we coauthored (➡️ carousel):

→ TrevorBirmingham expanded on our recent paper in Annals of Internal Medicine to report that reduced structural (cartilage) and pain progression of OA after high tibial osteotomy is largely explained by re-distribution of knee loading.

→ Simon Herger found that knee contact pressure during walking is related to cartilage thickness and T2 (qDESS MRI) in ACL injured knees.

→ StaffanLarsson explored the association of cytokine dynamics with 5-year location-independent cartilage changes after ACL injury.

→ Yi He demonstrated the relationship between baseline serum PRO-C2 and 2-year (lateral) cartilage thickness change in knee OA.

→ Frank Roemer examined the relationship of structural MRI phenotypes (ROAMS) and structural progression (by quantitative cartilage morphology)

Great thanks to our collaborators for sharing this exciting science:
Lauri Stenroth, Amir Esrafilian, Corina Nüesch, Barbara Postolka, Christian Egloff, Annegret Mündermann / Henrik Nilsson, Stefan Lohmander, André Struglics / Joscha Rombach, Christian Thudium, Monica Hannani, Simon Mastbergen, Mylène Jansen, Morten Asser Karsdal, Anne C. Bay-Jensen / Jamie Collins, David Hunter and Ali Guermazi.

We look forward to actively participating in OARSI 2027, taking place in April 2027 in Barcelona.
🙋 See you there !