## 2 Materials and Methods  
Our report included 15 patients, 11 men and 4 women, aged between 30 and 68. The patients were admitted and underwent surgery in the Plastic and Reconstructive Surgery Department of the \"Sf. Spiridon\" Emergency Clinical Hospital Iasi, as well as in the Orthopedics and Traumatology Department of the Vaslui Emergency Clinical Hospital between January 2016 and December 2018. The follow-up period was at least 2 years for each case. All the patients gave their consent for surgery and participation in this study. An agreement from the Ethics Committee of the Hospital was obtained. All cases were diagnosed with solitary enchondroma, and we did not include patients with multiple sites of enchondroma in this study. The suspicion of enchondroma was raised by plain radiographic findingsand clinical examination of the hand, and the diagnosis was confirmed by histopathology. Nine of the patients included in this report presented without symptoms. In these cases, the tumor was found accidentally on an X-ray taken for another reason. Three patients presented to the hospital for pain or swelling. In the other three cases, the first sign was a pathologic bone fracture. The fracture occurred during daily activities in the absence of trauma. All cases from this study had surgical indications due to the large volume of the tumor, affecting more than 50% of the cortical circumference. The surgical procedure consisted of curettage of the tumor cavity followed by filling or natural healing. In 9 of the 15 cases, the procedure was performed under regional anesthesia with a bloodless operative field by exsanguination and the use of a pneumatic tourniquet. The other six cases were performed under local anesthesia using the WALANT technique (Wide Awake Local Anesthesia No Tourniquet), using a solution of 1% Lidocaine with Epinephrine in a concentration of 1:100,000 [17]. After curettage, all the resected tissue was sent for anatomopathological examination and diagnosis establishment. In cases in which the tumor was located in the distal phalanx, after curettage, the cavity was left to heal naturally, and the finger required immobilization for 3 weeks in a plastic splint for middle phalanx, distal interphalangeal joint and distal phalanx in full extension (Figure 1). Figure 1: Enchondroma of the distal phalanx. (**A**)—radiological finding of enchondroma of the distal phalanx; (**B**)—excision of enchondroma using a surgical scoop; (**C**)—Excised tumor; (**D**)—bone defect after tumor excision, left for natural healing. In cases in which the tumor was located in the middle or proximal phalanx, the bone defect was filled with autologous cancellous bone graft harvested from the distal radius in four cases. The cancellous bone was harvested from the distal radius, radially to the Lister's tubercle from the floor of the second extensor compartment. A skin incision of 3 cm was performed over the extensor carpi radialis brevis (ECRB) tendon; the ECRB and extensor carpi radialis longus are retracted to the radial side, a hinge is used to perforate the cortex of the distal radius and the cancellous bone is harvested with a curette. The bone cortex and periosteum are closed, and the skin is sutured in anatomical layers. In the other seven cases, the bone defects were filled with injectable bone substitutes based on chitosan (k-IBS(r)). K-IBS(r) is presented in prefilled syringes with the ready-to-use bone substitute, so the bone substitute does not need any prior preparation before use. Osteosynthesis was performed with low profile miniplate and screws only in cases that presented signs of bone instability after tumor resection (Figure 2). Protected active and passive movement in the dynamic splint was performed on the 5 th postoperative day in all cases. We obtained early postoperative X-rays and compared them at 1, 6, 12 and 24 months in order to observe bone defect healing and the eventual tumor recurrence.