In children, we recommend regular clinical monitoring every year, with orthopaedic consultations, if possible at a Reference and/or Competence Centre, which can offer useful specialization in this rare pathology. They do not, however, eliminate the need for local monitoring and care, with the best possible coordination of all those involved. At present, there is no curative treatment, only essentially orthopedic care to treat the progressive complications of the disease. Fractures are not uncommon in children, and are usually treated with simple plaster cast immobilization. In Ollier disease, there are no problems with bone consolidation after fracture. Osteotomies with osteosynthesis, in particular centromedullary nailing, may be used for deformed, fragile and sometimes painful bone segments. For moderate inequalities in lower limb length (3 / 4 cm), growth is slowed on the longer limb by epiphysiodesis towards the end of growth. For greater inequalities, bone lengthening can be performed. Lengthening is relatively straightforward, as the bone regenerated by the lengthening is not chondromatous, and the growth disturbance concerns only the skeletal segment, with no shortening of other tissues (skin, muscles, vessels, nerves, etc.). If necessary, not only inequalities in length, but also axial deviations and limb rotation anomalies can be corrected simultaneously. Chondromas of the upper limbs can induce growth asymmetries, particularly of the two bones of the forearm, with a deviation of the wrist and hand that may be associated with dislocation of the radial head at the elbow. These antibrachial deformities need to be corrected at an early stage, before the onset of elbow dislocation, if possible. Chondromas of the hands need to be operated on at an early stage, before significant deformities and mobility limitations of the finger joints occur. The procedure is straightforward: the chondromatous areas are removed and the phalanges remodeled. It is rare in children to have to remove large, disabling chondromas. There is a risk of bleeding with these procedures, which should not be underestimated. In Maffucci syndrome, angiomas only appear towards the end of growth. Intrusive angiomas need to be removed, particularly in areas where the feet rest. It's not possible to remove them all, and they tend to recur. Finally, for children, we try to achieve optimal functional status at the end of growth. Finally, malignant transformations in children are very rare. Surgical procedures do not appear to entail any evolutionary risk for chondromas. On the other hand, treatment of degeneration in adults may be complicated by the presence of osteosynthesis material. Finally, in children, since it is impossible to cure the disease and remove all the chondromas, we remain modest in our surgical actions, limiting the number of interventions.