Wildeshausen

The prerequisite for participation in this observational study is the independent decision of the treating physician and patient to start an approved injectable or oral DMT for RMS as routine medical treatment. This decision must have been made prior to enrollment in this study. Cohort 1: The prospective observational period per patient in the core part will be up to approx. two years from the time of consent (2 years +2 months visit window). If a patient re-consents to the extension part, then the prospective extension observational period will be additional approx. two years, resulting in a total observational period (prospectively for the core and extension part \& retrospectively for the potential gap between core and extension part) of approx. 4 years (+ 2 month visit window). Cohort 2: The prospective observational period per patient will be up to approx. two years from the time of consent (2 years + 2 months visit window). The observational period will not be dictated by the protocol. The follow-up documentation will take place at a frequency defined as per investigator's discretion. The diagnostic or monitoring procedures are only those ordinarily applied to the therapeutic strategy and to routine clinical care, can be performed as telemedicine visits and will take place as per investigator's discretion.

The purpose of this project is to set up an international, multicenter registry of patient presenting with defects in long bones. Up to date, treatment remains challenging with little evidenced-based recommendations. For this purpose, any patient who presents at a study center with a bone defect of the defined expansion of any long bone is eligible for inclusion. Over a 3-year period as many patients as possible are included from the participating sites, at least 600 patients should be included in the registry. Details on any surgical intervention that is used to treat a bone defect will be recorded. Further patient-related and other pre-defined outcome measures will be collected. There is no formal hypothesis to this registry, hence it will help to identify prevalence and underlying etiologies, evaluate treatment strategies, and highlight possible challenges and complications - and will so help to gather clinical evidence to provide better treatment for patients suffering from a long bone defect.