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 TGFß1 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 TGFß1, 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 TGFß1 and BMP2 played an important role in this process.

[Clinical application of Fastpass Scorpion suture passer for arthroscopic Bankart repair].

Objective: To explore the effectiveness and advantages of using Fastpass Scorpion suture passer to stitch the inferior capsulolabral complex in arthroscopic Bankart repair compared with traditional arthroscopic suture shuttle. Methods: The clinical data of 41 patients with Bankart lesion, who met the selection criteria and were admitted between August 2019 and October 2021, was retrospectively analyzed. Under arthroscopy, the inferior capsulolabral complex was stitched with Fastpass Scorpion suture passer in 27 patients (FS group) and with arthroscopic suture shuttle in 14 patients (ASS group). There was no significant difference between the two groups ( P>0.05) in gender, age, injured side, frequency of shoulder dislocation, time from first dislocation to operation, and preoperative Rowe score of shoulder. Taking successful suture and pull-tightening as the criteria for completion of repair, the number of patients that were repaired at 5∶00 to 6∶00 (<6:00) and 6∶00 to 7∶00 positions of the glenoid in the two groups was compared. The operation time, and the difference of Rowe shoulder score betwee pre- and post-operation, the occurrence of shoulder joint dislocation, the results of apprehension test, and the constituent ratio of recovery to the pre-injury movement level between the two groups at 1 year after operation. Results: Both groups completed the repair at 5∶00 to 6∶00 (<6∶00), and the constituent ratio of patients completed at 6∶00 to 7∶00 was significantly greater in the FS group than in the ASS group ( P<0.05). The operation time was significantly shorter in the FS group than in the ASS group ( P<0.05). All incisions in the two groups healed by first intention. All patients were followed up 12-36 months (mean, 19.1 months). No anchor displacement or neurovascular injury occurred during follow-up. Rowe score of shoulder in the two groups significantly improved at 1 year after operation than preoperative scores ( P<0.05), and there was no significant difference in the difference of Rowe shoulder score between pre- and post-operation between the two groups ( P>0.05). At 1 year after operation, no re-dislocation occurred, and there was no significant difference in the apprehension test and the constituent ratio of recovery to the pre-injury movement level between the two groups ( P>0.05). Conclusion: Compared with the arthroscopic suture shuttle, using Fastpass Scorpion suture passer to stitch the inferior capsulolabral complex in arthroscopic Bankart repair is more convenient, saves operation time, and has good effectiveness.

[Effectiveness of proximal femoral nail anti-rotation combined with minimally invasive percutaneous plate osteosynthesis versus Intertan intramedullary nail fixation in treatment of intertrochanteric fracture with incomplete lateral wall].

OBJECTIVE: To compare the effectiveness of proximal femoral nail anti-rotation (PFNA) combined with minimally invasive percutaneous plate osteosynthesis (MIPPO) and Intertan intramedullary nail fixation by closed reduction in the treatment of AO/Orthopaedic Trauma Association (AO/OTA) type 31-A3.3 intertrochanteric fracture with incomplete lateral wall. METHODS: The clinical data of 54 patients with AO/OTA type 31-A3.3 intertrochanteric fracture who met the selection criteria and were admitted between January 2012 and January 2018 were retrospectively analyzed. According to different surgical methods, the patients were divided into group A (24 cases with lateral wall reconstruction by MIPPO combined with PFNA internal fixation) and group B (30 cases with Intertan intramedullary nail fixation by closed reduction only). There was no significant difference between the two groups ( P>0.05) in terms of gender, age, side of injury, cause of injury, and combined medical diseases. The operation time, intraoperative blood loss, time to weight-bearing, fracture healing time, and postoperative complications were recorded and compared between the two groups. The tip apex distance (TAD) was measured at 2 days, 2 months, and 1 year after operation. At 12 months after operation, the hip joint function was evaluated according to Harris scoring standard, and the rate of conformity (Harris score were more than 70) was calculated. RESULTS: The wounds of the two groups healed by first intention, without infection, skin deformity, and other incision complications. The operation time and intraoperative blood loss of group A were significantly more than those of group B, and the time to weight-bearing and fracture healing were significantly shorter than those of group B ( P<0.05). The patients were followed up 9-20 months (mean, 14.7 months) in group A and 9-19 months (mean, 13.8 months) in group B. There was no significant difference in TAD values at 2 days, 2 months, and 1 year after operation between the two groups ( P<0.05), and there was also no significant difference in TAD values between the postoperative time points ( P>0.05). There was 1 case of infection, 1 case of screw withdrawal, 2 cases of screw removal, and 1 case of bone nonunion in group B, the incidence of complications was 16.7%; there was only 1 case of screw withdrawal combined with screw blade withdrawal in group A, the incidence of complications was 4.2%; there was no significant difference between the two groups ( χ 2=2.109, P=0.146). At 12 months after operation, the Harris scores of pain, function, malunion, range of motion, and total score in group A were significantly better than those in group B ( P<0.05). The rate of conformity of group A was 95.83% (23/24) and 76.67% (23/30) in group B, and the difference between the two groups was significant ( χ 2=3.881, P=0.049). CONCLUSION: For the AO/OTA type 31-A3.3 intertrochanteric fracture with incomplete lateral wall, compared with the closed reduction Intertan intramedullary nail fixation, the incidence of internal fixation failure after MIPPO reconstruction with lateral wall combined with PFNA fixation was lower, the time to weight-bearing was earlier, and the postoperative function was better.

[Effect of stromal cell-derived factor 1α/cysteine X cysteine receptor 4 signaling pathway on axial stress stimulation promoting bone regeneration].

OBJECTIVE: To observe the change of stromal cell-derived factor 1α/cysteine X cysteine receptor 4 (SDF-1α/CXCR4) signaling pathway during the process of axial stress stimulation promoting bone regeneration, and to further explore its mechanism. METHODS: A total of 72 male New Zealand white rabbits were selected to prepare the single cortical bone defect in diameter of 8 mm at the proximal end of the right tibia that repaired with deproteinized cancellous bone. All models were randomly divided into 3 groups ( n=24). Group A was treated with intraperitoneally injection of PBS; Group B was treated with stress stimulation and intraperitoneally injection of PBS; Group C was treated with stress stimulation and intraperitoneally injection of AMD3100 solution. The X-ray films were taken and Lane-Sandhu scores of bone healing were scored at 2, 4, 8, and 12 weeks after operation, while specimens were harvested for HE staining, immunohistochemical staining of vascular endothelial growth factor (VEGF) and CXCR4, and Western blot (SDF-1α and CXCR4). The bone healing area was scanned by Micro-CT at 12 weeks after operation, and the volume and density of new bone were calculated. RESULTS: X-ray film showed that the Lane-Sandhu scores of bone healing in group B were significantly higher than those in groups A and C at 4, 8, and 12 weeks after operation ( P<0.05). Micro-CT scan showed that the bone defect was repaired in group B and the pulp cavity was re-passed at 12 weeks after operation. The volume and density of new bone were higher in group B than in groups A and C ( P<0.05). HE staining showed that the new bone growth in bone defect area and the degradation of scaffolds were faster in group B than in groups A and C after 4 weeks. The immunohistochemical staining showed that the expressions of VEGF and CXCR4 in 3 groups reached the peak at 4 weeks, and group B was higher than groups A and C ( P<0.05). Western blot analysis showed that the expressions of SDF-1α and CXCR4 in group B were significantly higher than those in groups A and C at 4 and 8 weeks after operation ( P<0.05). CONCLUSION: Axial stress stimulation can promote the expression of SDF-1α in bone defect tissue, activate and regulate the CXCR4 signal collected by marrow mesenchymal stem cells, and accelerate bone regeneration in bone defect area.

Co-culture of the bone and bone marrow: a novel way to obtain mesenchymal stem cells with enhanced osteogenic ability for fracture healing in SD rats.

BACKGROUND: Mesenchymal stem cells (MSCs) have great potential for the repair and regeneration of bone fracture, but their optimal origins remain controversial. METHODS: Bone marrow-MSCs (BM-MSCs) and bone-bone marrow-MSCs (B-BM-MSCs) were isolated from 12 SD rats, and the morphology, MSC-associated markers, and proliferative capacity of these cells were compared using an inverted microscope, flow cytometry, and CCK-8 assays, respectively. After 14 days of osteoblastic induction, osteoblast phenotypes were detected by ALP and calcium nodule staining, and the expression of BMP-2 and TGF-ß1 was observed by western blotting. Then, the rat tibia fracture model was established with 3 groups (n = 6 per group), the control, BM-MSC, and B-BM-MSC groups. Computed tomography (CT) imaging was performed to evaluate fracture healing at weeks 2, 4, and 6. Finally, the fractured bones were removed at weeks 4 and 6, and HE staining was performed to evaluate fracture healing. RESULTS: Although the 2 types of MSCs shared the same cellular morphology and MSC-associated markers, B-BM-MSCs had a higher proliferative rate than BM-MSCs from day 9 to day 12 (p < 0.05), and the expression levels of ALP and calcium were obviously higher in B-BM-MSCs than in BM-MSCs after osteogenic induction (p < 0.01 and p < 0.001, respectively). Western blot results showed that the expression levels of BMP-2 and TGF-ß1 in B-BM-MSCs were higher than in BM-MSCs before and after osteogenic induction (p < 0.01). In the animal experiments, CT imaging and gross observation showed that B-BM-MSCs had a greater capacity than BM-MSCs to promote fracture healing, as the Lane-Sandhu scores of B-BM-MSCs at weeks 4 and 6 after operation (3.00 ± 0.81 and 9.67 ± 0.94, respectively) were higher than those of BM-MSCs (1.33 ± 0.47 and 6.67 ± 1.25, respectively; both p < 0.05). The HE staining results further supported this conclusion. CONCLUSIONS: Taken together, our study results proved that MSCs obtained by co-culturing the bone and bone marrow from SD rats had better proliferative, osteogenic differentiation, and fracture healing capacities than BM-MSCs, perhaps suggesting a novel way to obtain MSCs for bone tissue repair.