Arthrogryposis Multiplex Congenita in Pediatric Age: Correlation Between MUScular MRI and Functional Evaluation (AMUSE), Toward a Biomechanical Model.

Arthrogryposis Multiplex Congenita (AMC) is a group of diseases with joint limitations at two or more distinct joint levels at birth. Joint limitations are not progressive, but the functional consequences have a lifelong impact on patients. The management of these conditions is therefore demanding, necessarily multidisciplinary, and is a long-term process. The aim of our study was to evaluate the correlation between muscle fat infiltration and deficiencies and activity limitations in children with AMC. We conducted a monocentric retrospective observational study including patients with exclusive pediatric follow-up evaluated at the AMC Reference Centre (RC) of the University Hospital of Grenoble Alpes between 2010 and 2022. We included 97 patients, of whom 50% had Amyoplasia. We showed that, all groups combined, the Mercuri score was significantly correlated with PROM in the upper and lower limbs, with muscular weakness in the lower limbs, and also with reaching ability. Our study is one of the first in a pediatric population to investigate the link between muscle imaging and functional aspects of AMC. Muscle MRI is a recognized and recommended tool for diagnosis and also a suitable noninvasive tool to assess and assist in the functional prognosis of patients.