A Clinical Study to Evaluate the Safety and Efficacy of Biologic Hollow Bone Screws

Traditional fracture fixation devices can cause corrosion, allergies, and stress shielding effects. They often require removal after healing, risking secondary damage. Recently, biodegradable materials have gained attention for their effective clinical use in fracture fixation. Absorbable bone nails, for example, eliminate the need for a second surgery, reducing pain and costs while avoiding infection and tissue re-injury. They do not corrode and are invisible on X-rays, allowing for thorough patient examination and better fracture healing assessment.

Traditional fracture internal fixation devices implanted in the human body for a long time will cause corrosion, allergy and adverse effects due to stress shielding effect, etc. Due to the non-absorbability of its own materials, it needs to be removed again after fracture healing, which is easy to cause secondary damage to patients. However, in recent years, biodegradable materials have attracted the attention of scholars. The fracture fixation made of biodegradable biomaterials has achieved better internal fixation effect in clinic. For example, the implantation of absorbable bone nails can enable patients to avoid a second surgery, reduce the pain and economic burden of patients, while avoiding the problems of infection and tissue re-injury caused by the second surgery. In addition, absorbable bone nails have no metal corrosion effect and are not visible under the X-ray line, which is conducive to comprehensive examination of the patient and further understanding of the fracture healing. Common biodegradable materials are polymer materials (such as polylactic acid), ceramic materials (such as calcium phosphate) and metal materials. Among them, the strength of polymer materials is lower, and the toughness of ceramic materials is poorer, while the bone nails made of natural silk protein are biocompatible, non-toxic, no irritant, no side-effective, no antigenic and no carcinogenic to tissues. It can be completely degraded into amino acids and peptides in the body, participate in human metabolism, and eventually be excreted from the body. Silk was first used as a surgical suture, which can be gradually absorbed and degraded by the body after wound healing, which protected patients from the pain of removing stitches. Animal experiments have shown that the use of silk protein gel and commonly used ethyl lactate to repair rabbit thigh bone injuries, with the number, thickness and gap of bone trabeculae as evaluation indexes, the result showed that the use of silk protein gel was more conducive to the repair of rabbit thigh bone injury, and was also closer to the regeneration of human bone. In addition, the silk was able to maintain 50% tension two months after implantation in the animals.

Therefore, the purpose of this clinical trial study was to evaluate the safety and effectiveness of biologic hollow bone screws for the fixation of fractures in the knee joint and ankle joint. Researchers can use the above results to provide better treatment for patients.

Eligibility Criteria:
Inclusion criteria

1. Aged 18-75 years old (inclusive), both sexes;
2. Patients with knee and ankle fractures requiring internal fixation confirmed by imaging examination;
3. Voluntary participation in the clinical trial and signing of the informed consent.

Exclusion criteria

1. The following conditions exist at the fracture site: infection, osteofascial compartment syndrome, osteitis, pathological fracture, open fracture, severe tissue or vascular and nerve injury, or insufficient bone mass of the affected limb affecting screw implantation, etc.
2. Abnormal liver and kidney function with clinical significance (ALT, AST 2 times the upper limit of normal value and Cr 2 times the upper limit of normal value);
3. Abnormal coagulation function with clinical significance (APTT \> 2 times the upper limit of normal value);
4. Patients with difficult-to-control diabetes (any blood glucose \> 11.1mmol/L or glycosylated hemoglobin \> 9%);
5. Past allergies to silk protein materials;
6. Mental illness;
7. Patients who cannot guarantee to quit smoking during the fracture healing period;
8. Pregnant or lactating women or women of childbearing age who plan to get pregnant within 6 months;
9. Those who have participated in other pre-clinical trials within 1 month before the trial;
10. Those who are considered inappropriate to participate in the clinical trial.