This study is designed to perform a head-to-head comparison of two synthetic ceramic bone graft substitutes, bioactive glass (BAG) and beta-tricalcium phosphate (TCP), in filling of contained bone defects following surgical evacuation of benign bone tumor or tumor-like conditions. Based on the investigators' previous preclinical research and an ongoing single-center randomized clinical trial on bioactive glass filling, the investigators expect BAG filling to be more efficient compared to TCP in promotion of defect healing and functional recovery after surgery.

This study is designed to perform a head-to-head comparison of two synthetic ceramic bone graft substitutes, bioactive glass (BAG) and beta-tricalcium phosphate (TCP), in filling of contained bone defects following surgical evacuation of benign bone tumor or tumor-like conditions. Small metacarpal and phalangeal enchondromas (Stratum I) and large long-bone lesions (Stratum II) will be evaluated separately. Aside with the head-to-head comparison of the two synthetic bone graft substitutes, autologous bone graft (Stratum I) and allogeneic bone graft (Stratum II) will be used as the standard of care controls.

Inclusion Criteria:

• Patients with primary or recurrent benign bone tumor or tumor-like condition that requires operative treatment by means of tumor evacuation and defect filling
• Pathological fractures of patients in Stratum I are treated by means of conservative treatment for three months before tumor surgery

Exclusion Criteria:

• History of acute or chronic local infection
• History of malignancy (excluding carcinoma basocellular) within past 5 years
• A history of local radiotherapy
• A known metabolic skeletal disease (such as osteoporosis, Paget's disease or osteomalacia)
• Medication affecting bone turnover (oral bisphosphonates, PTH, sodium fluoride, strontium ranelate, calcitonin, testosterone, systemic cortico- or anabolic steroids)
• Any plans to use phenol or other chemical/thermal method of local tumor control
• Pregnancy
• Any other condition that in the judgment of the investigator, would prohibit the subject from participating in the study or may hinder the collection of data and interpretation of the results

Adult patients with primary or recurrent benign bone tumor or tumor-like condition that requires operative treatment by means of tumor evacuation and defect filling.