Dr. Geller is a full-time faculty member of the Orthopaedic Surgery Department at Montefiore Medical Center and serves as the director of the Orthopaedic Oncology Service, managing both pediatric and adult patients. He is the co-director of Orthopaedic Surgery at the Montefiore Medical Center Moses Campus and currently serves as the Quality Improvement Officer for the Montefiore Cancer Committee. His clinical focus involves primary and metastatic bone and soft tissue tumors, with a secondary interest in joint replacement in the setting of extensive bone loss. He has experience in navigation-guided surgery, allograft reconstruction, endoprosthetic reconstruction, and use of custom or patient-tailored reconstructive prostheses. His research interests include expression patterns in osteosarcoma, surgical margins in osteosarcoma, novel drug screening methods and targeted therapy for osteosarcoma using novel therapeutic modalities. He is extensively involved in resident and medical student education.