Rap system of stress stimulation can promote bone union after lower tibial bone fracture: a clinical research

Combination of optimized tissue engineering bone implantation with heel-strike like mechanical loading to repair segmental bone defect in New Zealand rabbits

In this study, effects of combining optimized tissue engineering bone (TEB) implantation with heel-strike like mechanical loading to repair segmental bone defect in New Zealand rabbits were investigated. Physiological characteristics of bone marrow mesenchymal stem cells (BMMSCs), compact bone cells (CBCs), and bone marrow and compact bone coculture cells (BMMSC-CBCs) were compared to select the optimal seed cells for optimized TEB construction. Rabbits with segmental bone defects were treated in different ways (cancellous bone scaffold for group A, cancellous bone scaffold and mechanical loading for group B, optimized TEB for group C, optimized TEB and mechanical loading for group D, n = 4), and the bone repair were compared. BMMSC-CBCs showed better proliferation capacity than CBCs (p < 0.01) and stronger osteogenic differentiation ability than BMMSCs (p < 0.05). Heel-strike like mechanical loading improved proliferation and osteogenic differentiation ability and expression levels of TGFβ1 as well as BMP2 of seed cells in vitro (p < 0.05). At week 12 post-operation, group D showed the best bone repair, followed by groups B and C, while group A finished last (p < 0.05). During week 4 to 12 post-operation, group D peaked in terms of expression levels of TGFβ1, BMP2, and OCN, followed by groups B and C, while group A finished last (p < 0.05). Thus, BMMSC-CBCs showed good proliferation and osteogenic differentiation ability, and they were thought to be better as seed cells than BMMSCs and CBCs. The optimized TEB implantation combined with heel-strike like mechanical loading had a synergistic effect on bone defect healing, and enhanced expression of TGFβ1 and BMP2 played an important role in this process.

[Effectiveness of autologous femoral head bone graft in total hip arthroplasty for Crowe type developmental dysplasia of hip with acetabular bone defect]

Objective

To explore the surgical technique and effectiveness of autologous femoral head bone graft in total hip arthroplasty (THA) for Crowe type Ⅲ developmental dysplasia of the hip (DDH) with acetabular bone defect.

Methods

Between July 2012 and September 2015, 12 cases (12 hips) of Crowe type Ⅲ DDH with acetabular bone defect were included. Of the 12 patients, 2 were male and 10 were female, with an average age of 54.3 years (range, 37-75 years). The Harris score before operation was 41.08±7.90. The preoperative leg length discrepancy was 0.53-4.28 cm, with an average of 2.47 cm. Autologous femoral head bone graft and cancellous screw fixation were used in all cases to reconstruct acetabula in THA. Four cases were performed with subtrochanteric shortening osteotomy at the same time.

Results

All incisions healed by first intention. Twelve cases were followed up 1 year and 10 months to 5 years, with an average of 3.0 years. X-ray films showed that bone healing was observed in all cases at 6 months to 1 year after operation. There was no bone graft osteolysis, absorption, bone graft collapse, and acetabular prosthesis loosening. At last follow-up, the Harris score was 89.50±2.78, showing significant difference when compared with preoperative value ( t=-25.743, P=0.003). The length discrepancy was 0-1.81 cm at last follow-up with an average of 0.76 cm.

Conclusion

Autologous femoral head bone graft is effective for Crowe type Ⅲ DDH with acetabular bone defect, which has advantages of restoring pelvic bone stock, obtaining satisfied prosthetic stability and mid-term effectiveness.

Combination of Heel-strike like Mechanical Loading with Deproteinized Cancellous Bone Scaffold Implantation to Repair Segmental Bone Defects in Rabbits

Under physiological conditions bone defects often occur at mechanical load bearing sites and bone substitutes used for regeneration should be similarly subjected to mechanical loading stress. In this study, we investigated whether a novel heel-strike like mechanical loading method can be used as a complementary therapy to promote bone regeneration following bone substitute grafting. To test this, three groups of rabbits with segmental bone defects in the tibia were implanted with bovine deproteinized cancellous bone scaffold (DCBS), with one group also receiving heel-strike like mechanical loading generated by a rap stress stimulator. From weeks 4-12 post-operation X-ray and micro-CT scanning showed that rabbits receiving combination therapy had significantly more callus at the bone defect. Moreover, bone defects in the combination group were completely replaced with new bone at week 12, while the DCBS implantation alone group healed only partially and rabbits receiving neither DCBS nor mechanical loading developed only small calluses throughout the observation period. Analysis of micro-CT scanning results demonstrated that new bone density in the combination group was significantly higher than the DCBS only group at weeks 4 and 12 (p<0.05). H&E staining results also indicated a significantly higher percentage of new bone in the bone defect area and a lower percentage of residual scaffold in the combination group compared to the DCBS only group (p<0.05). Thus, this heel-strike like mechanical loading method appears to accelerate bone regeneration following substitute implantation by restoring a local mechanical loading environment in segmental bone defects.