Langerhans cell histiocytosis is rare and frequently involves the bone. We retrospectively reviewed the orthopaedic aspects (symptoms, localizations, treatments) and the long-term outcome [disease status, overall survival (OS), event-free survival (EFS)] of 121 patients (June 1968–December 2009). The main symptom was local pain. The orthopaedic treatment was mainly conservative. The most frequent localization was osseous monofocal (62% of monosystemic diseases). Monosystemic and osseous monofocal localizations, treatment after 1991 (OS, P=0.007; EFS, P=0.03) and age older than 2 years (OS, P=0.003; EFS, P=0.001) were prognostic factors that were positively associated with survival. Oncologic treatment has improved over time, translating into better survival. A biopsy is often mandatory.