Illustration and schematization of the long-term outcome results. Results of the 2013 study by Krämer et al,²⁰  underlining that progression of joint arthropathy during intensive prophylaxis regimens is a process with subtle progression over years. Scores ≥2 are regarded to be pathological. The ankle joints are the first joints that develop arthropathy after a median time of 10 years, followed by knee joints and elbow joints significantly later. The clinical Gilbert scores are following the Pettersson scores 1 to 2 decades later. The gray area indicates the initial decade of prophylactic treatment when early joint disease remains undetected by the Pettersson score. GS, Gilbert score; PS, Pettersson score.