AGE-SPECIFIC AND JOINT-SPECIFIC RISK OF INITIAL HETEROTOPIC OSSIFICATION IN PATIENTS WHO HAVE FIBRODYSPLASIA OSSIFICANS PROGRESSIVA

Using data from a survey of 44 patients who have fibrodysplasia ossifi cans progressiva, age- and joint-specific risks of new joint involveme nt were estimated using parametric and nonparametric statistical metho ds. Regions in which the risk of heterotopic ossification appears to r emain constant with age include the neck, spine, shoulders, elbows, an d ankles. Regions with apparently increasing risk include the jaw, wri sts, hips, and knees. This analysis allows clinicians to estimate the risk of new involvement for any joint at any patient age, as well as t he fraction of patients with uninvolved joints at any age. The variati on of ossification risk by joint provides a clinically useful guide to the patterns of progression of the disease. Such a guide will help in planning for individual patient needs, as well as anticipating auxili ary social services and rehabilitation programs.