Clinical Efficacy Study of Magnesium-Containing Degradable Polymer Bone Repair Material for Bone-Defect Repair After Extremity Bone Tumor Resection

This investigator-initiated single-center prospective randomized open-label non-inferiority trial plans to recruit 72 adult subjects with bone defects following extremity bone tumor or tumor-like lesion resection. Randomization will be stratified by upper-limb versus lower-limb defect location to balance mechanical load confounding between groups, with 36 subjects allocated to each arm.

After standard tumor resection, the experimental group receives implantation of magnesium-containing degradable polymer bone repair material. The control group uses commercially available conventional bone repair material without magnesium. Post-operative standardized care protocols including antibiotic prophylaxis, stepwise analgesia regimen, wound dressing and weight-bearing rehabilitation are identical for both groups. Opioid consumption will be converted to morphine-equivalent dose for primary endpoint analysis, with a pre-specified non-inferiority margin of 9.726 mg morphine equivalent. At 1-, 3- and 6-month follow-ups, thin-slice CT scans are performed for quantitative 3D reconstruction to assess new bone formation volume. Two independent radiology reviewers blinded to group assignment conduct volumetric measurement to reduce assessment bias. Surgical-site infection is defined by combined clinical manifestation, laboratory tests and bacterial culture results. Local tumor recurrence is confirmed by imaging or pathological biopsy. Safety assessments cover material-related adverse reactions, implant-associated complications and surgery-related adverse events.Statistical analyses will test non-inferiority for the primary endpoint. Continuous secondary outcomes will be analyzed using t-test or rank-sum test; categorical variables will adopt Chi-square test or Fisher's exact test. Subgroup analyses for upper-limb and lower-limb subgroups will be performed. Both full-analysis set and per-protocol set will be used for efficacy assessment. This trial follows the Declaration of Helsinki and has obtained institutional ethics committee approval. Written informed consent will be obtained from each participant before enrolment.

Inclusion criteria

• Subjects with bone tumors (benign or borderline) or tumor-like bone lesions of extremities confirmed by imaging and/or pathology, scheduled for surgical resection.
• Bone defects formed after resection of extremity bone tumor, requiring artificial bone repair material for defect filling and reconstruction.
• Age from 18 to 75 years old, regardless of gender.
• Good general preoperative condition and able to tolerate surgical treatment.
• Voluntarily participate in this study, provide written informed consent, and be judged by investigators to comply with study protocol and complete follow-up visits.
• No postoperative local rejection or allergic reaction at the operative site.
• Diameter of bone defect ≤ 6 cm, and product usage volume ≤ 77 cm³.
• Bone defect located in upper extremity (humerus, ulna-radius, carpal bones) or lower extremity (femur, tibia, fibula, ankle, foot bones).

Exclusion criteria

• Active local infection at operative site or severe systemic infection.
• Severe bone metabolic diseases that may interfere with bone healing, such as severe osteoporosis or uncontrolled hyperparathyroidism.
• Severe cardiac, hepatic, renal insufficiency or other serious systemic diseases which cannot tolerate surgery or interfere with study evaluation.
• Severe hematological or immune system disorders.
• Pregnant or lactating women.
• Expected survival less than 12 months, or unable to complete at least 12-month follow-up.
• Known or suspected allergy to collagen, hydroxyapatite or other components of bone repair materials.
• Occurrence of local rejection or allergic reaction at operative site after surgery.
• Diameter of bone defect > 6 cm, or product usage volume > 77 cm³.
• Any other conditions judged by investigators making the subject unsuitable for enrollment.