Clinical result of sintered bovine hydroxyapatite bone substitute: analysis of the interface reaction between tissue and bone substitute

Treatment study of distal femur for parathyroid hormone (1-34) and β-tricalcium phosphate on bone formation in critical-sized defects in osteopenic rats

The objective of this study was to evaluate the effect of following combined treatment with parathyroid hormone (1-34) (PTH) and β-tricalcium phosphate (β-TCP) on local bone formation in a rat 3-mm critical-sized defect at the distal femur. Fourteen weeks were allowed to pass before defect surgery for the establishment of osteopenic animal models chronically fed a low-protein diet. All animals were randomly divided into four groups: group PTH; group β-TCP, group PTH + β-TCP, and a control group. All rats then underwent a surgical procedure to create bone defects in the bilateral distal femurs, and β-TCP was implanted into critical-sized defects for the groups designated as β-TCP and group PTH + β-TCP. After the defect operation, all animals from group PTH and group PTH + β-TCP received following subcutaneous injections with PTH (60 μg/kg, three times per week) until euthanasia at 4 and 8 weeks. The distal femurs and blood were collected for evaluation. The results of study showed the strongest effect on accelerating the local bone formation with treatment β-TCP and PTH at 4 weeks and 8 weeks. The results from our study demonstrate that a combination of PTH and β-TCP had an additive effect on local bone formation in osteopenic rats chronically fed a low-protein diet.

Hydroxyapatite crystals as a bone graft substitute in benign lytic lesions of bone

BACKGROUND

Bone grafts are required to fill a cavity created after curettage of benign lytic lesions of the bone. To avoid the problems associated at donor site with autologous bone graft, we require allograft or bone graft substitutes. We evaluated the healing of lytic lesions after hydroxyapatite (HA) grafting by serial radiographs.

MATERIALS AND METHODS

Forty cases of benign lytic lesions of bone were managed by simple curettage and grafting using HA blocks. Commercially available HA of bovine origin (Surgiwear Ltd., Shahjahanpur, India) was used for this purpose. Mean duration of followup was 34.8 months (range 12-84 months). Mean patient age was 19.05 years (range 3-55 years). Radiological staging of graft incorporation was done as per criteria of Irwin et al. 2001.

RESULTS

In our series, two cases were in stage I. A total of 11 cases were in stage II and 27 were in stage III. Graft incorporation was radiologically complete by 15 months. Clinical recovery was observed before radiological healing. The average time taken to return to preoperative function was 3 months. Recurrence was observed in giant cell tumor (n = 3) and chondromyxoid fibroma (n = 1). There was no incidence of graft rejection, collapse, growth plate disturbances or antigenic response.

CONCLUSIONS

We conclude that calcium HA is biologically acceptable bone graft substitute in the management of benign lytic lesions of bone.

Stimulation of healing within a rabbit calvarial defect by a PCL/PLGA scaffold blended with TCP using solid freeform fabrication technology

The purpose of this study was to investigate the healing capacity within an 8-mm rabbit calvarial defect using a polycaprolactone (PCL)/poly(lactic-co-glycolic acid) (PLGA) scaffold blended with tri-calcium phosphate (TCP) that was constructed using solid freeform fabrication (SFF) technology. The PCL/PLGA/TCP scaffold showed a 37 % higher compressive strength and rougher surface than the PCL/PLGA scaffold. In animal experiments, new bone formation was analyzed using microcomputed tomography (micro-CT) and histological and histometric analyses. The PCL/PLGA/TCP groups had significantly greater neo-tissue areas as compared with the control groups at 4 and 8 weeks (P < 0.05). The PCL/PLGA/TCP group had significantly greater bone density as compared with the control and PCL/PLGA groups at 4 and 8 weeks (P < 0.005). The results of this study suggest that the PCL/PLGA/TCP scaffold fabricated using SFF technology is useful for recovering and enhancing new bone formation in bony defects in rabbits.