Background: Diabetic cheiroarthropathies consist of limited joint mobility (LJM), flexor tenosynovitis (FTS), Dupuytren's contracture (DC), and carpal tunnel syndrome (CTS). There is heterogeneity in definitions and lack of a method to measure hand fibrosis load. We measured metacarpophalangeal (MCP) joint restriction and describe magnetic resonance (MR) imaging characteristics across the spectrum of joint restriction. Methods: Adults with type 1 diabetes were screened for hand manifestations using a symptom questionnaire, clinical examination, function (Duruoz hand index (DHI), grip strength). We measured maximum possible extension at the MCP joint. Patients were segregated by mean MCP extension (<20 degrees, 20-40 degrees, 40-60 degrees, and >60 degrees) for MRI scanning. Patients in the four groups were compared using ANOVA for clinical features as well as MRI measurements (tenosynovial, skin, and fascia thickness, additive score of three). Findings: Of 237 patients (90 males), 79 (33.8%) had cheiroarthropathy; these had MCP extension limitation (39 degrees versus 61 degrees, p<0.01). Groups with restricted MCP extension were older, had higher prevalence of retinopathy and nephropathy, and higher DHI (1.9 vs 0.2) but very few (7%) had pain. MRI scans of the hand (n=61) showed flexor tenosynovitis in four and median neuritis in one. Groups with maximum MCP limitation had the thickest palmar skin but mean tendon thickness or median nerve area did not differ. The additive score could differentiate between levels of joint mobility restriction. Only mean palmar skin thickness was associated with MCP extension angle in multiple linear regression. Interpretation: Joint mobility limitation, quantified by restricted MCP extension, was driven by skin thickening. MCP extension and fibrosis scoring on MRI can serve as quantitative measures of hand involvement for future associative studies.

The authors have declared no competing interest.

This study is funded through a DBT/Wellcome India Alliance Clinical and Public health fellowship (IA/CPHE/19/504607). The funding body had no role in study design or analysis.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Ethics committee of KEM Hospital Research Centre gave ethical approval for this work (KEMHRC/RVC/EC/1518). Patients signed separate informed consent forms for clinical examination, photographs, and MRI scan. The study was registered with the Clinical Trials Registry of India (CTRI/2020/12/030057). Data sharing agreements were signed with Star Imaging and Research Centre and Indian Institute of Science Education and Research (IISER), Pune. Ethics committee of Indian Institute of Science Education and Research waived ethical approval for this work (IECHR, Admin/2021/007).

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I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

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All clinical and imaging data are stored at the Diabetes Unit, KEM Hospital Research Centre.