Musculoskeletal disorders in juvenile onset mixed connective tissue disease

Objective. We studied the occurrence of musculoskeletal involvement in patients with juvenile onset mixed connective tissue disease (MCTD) and their functional ability. Methods. Thirteen patients who fulfilled the Kasukawa criteria of MCTD, were subjected to a general orthopedic assessment, as well as to a specific examination of tenderness and swelling of joints, muscle strength, joint motion and alignment, radiographical evaluation, and on disability and discomfort. Results. Low indices were found on the modified Ritchie Articular Index (RI) (0.07) and the Fuchs Swelling Index (0.13). Mild to moderate indices were measured on the Joint Alignment and Motion Scale (JAM) (0.52) and on the Larsen Radiographic Evaluation Scales for the wrist, metacarpal, proximal and distal interphalangeal joints (L-RES) (1.40, 0.62, 0.31, 0.31). The mean pulp-thickness ratio was 22%, which is an indication for sclerodermic changes in the hands. Proximal muscle weakness was found in 10/13 patients (mainly in the upper extremity), distal muscle weakness was found in 12/13 patients. On the pediatric version of the Stanford Health Assessment Questionnaire (C-HAQ), pain and discomfort scored 0.04, disability scored 0.46; those scores were considered to be low. Between L-RES and JAM a significant correlation was found (0.74, 0.74 and 0.73; p < 0.01). Another significant correlation was found between the RI and the disablity score of the HAQ (0.58; p < 0.05). Conclusion. Sclerodermic changes as well as arthritic changes are of a benign character in our population of patients with juvenile onset MCTD.