Bone Regeneration by Multichannel Cylindrical Granular Bone Substitute for Regeneration of Bone in Cases of Tumor, Fracture, and Arthroplasty

Abstract

In orthopedics, a number of synthetic bone substitutes are being used for the repair and regeneration of damaged or diseased bone. The nature of the bone substitutes determines the clinical outcome and its application for a range of orthopedic clinical conditions. In this study, we aimed to demonstrate the possible applications of multichannel granular bone substitutes in different types of orthopedic clinical conditions, including bone tumor, fracture, and bone defect with arthroplasty. A clinical investigation on a single patient for every specific type of disease was performed, and patient outcome was evaluated by physical and radiographic observation. Brief physical characterization of the granular bone substitute and in vivo animal model investigation were presented for a comprehensive understanding of the physical characteristics of the granules and of the performance of the bone substitute in a physiological environment, respectively. In all cases, the bone substitute stabilized the bone defect without any complications, and the defect regenerated slowly during the postoperative period. Gradual filling of the defect with the newly regenerated bone was confirmed by radiographic findings, and no adverse effects, such as osteolysis, graft dispersion, and non-union, were observed. Homogeneous bone formation was observed throughout the defect area, showing a three-dimensional bone regeneration. High-strength multichannel granules could be employed as versatile bone substitutes for the treatment of a wide range of orthopedic conditions.

Keywords: bone defects; bone regeneration; calcium phosphate; granular bone substitutes.

Figure 1

Optical micrographs of different size multichannel granular bone substitutes. (a) 1 mm diameter, (b) 2 mm diameter and (c) 3 mm diameter.

Figure 2

Physical and mechanical characterization of the granular bone substitute (a) pore size, (b) compressive strength. ** ≤0.01, *** ≤0.001.

Figure 3

H&E-stained tissue section of granular bone substitute implanted bone areas. (a–c) Bone formation after 1 month of implantation with 1 mm granule. (d–f) bone formation after 2 months of implantation. Legend: BS (Bone substitute), NB (New Bone).

Figure 4

Bone regeneration in the bone void due to the osteofibrous dysplasia. (a,b) Preop condition, (c,d) postop condition, (e,f) after one month of operation and (g,h) after 12 months of operation. CT images of the (i) tissue lesion of the dysplasia before operation and (j) regenerated bone after 12 months postop. The red circles indicate implanted defect zone.

Figure 5

Simple bone cyst in the intertrochanter region of the femur was removed and granular bone substitute used for bone regeneration. (a,b) X-ray and MRI diagnosis of the bone cyst, (c,d) postop condition with application of granular bone substitute and support implant, (e,f) after 3 months of operation and (g,h) after 3 years of operation. The red circles indicate implanted defect zone.

Figure 6

MRI of simple bone cyst formation in the intertrochanter region of the femur causing a compound fracture. (a) MRI of the fractured bone in the coronal plane. (b) MRI of the fractured bone in the axial plane.

Figure 7

Fracture of intertrochanter region of the femur after a cyst formation was treated with granular bone substitute. (a,b) X-ray of the bone fracture, (c,d) postop condition with application of granular bone substitute and support implant, (e,f) after 5 months of operation and (g,h) after 3 years of operation. Red circle indicate defect zone with fracture.

Figure 8

Primary arthroplasty of the hip joint treated with granular bone substitute for restoration of new bone in the necrossed bone (a,b) X-ray of the bone with necrosis, (c,d) postop condition with application of granular bone substitute around the hip joint implant, (e,f) new bone formation at the granular bone graft site after one months of operation and (g,h) after 6 years of operation condition. The red circles indicate implanted defect zone.