Objective To investigate the effect of canine decellularized tendon slices (DTSs) on tendon-bone healing in repairing rotator cuff injury of rabbit. Methods Canine DTSs were prepared by repetitive freeze/thaw 5 times combined with nuclease processing for 12 hours from the adult Beagles Achilles tendons. Histological observation and cytocompatibility evaluation for the canine DTSs were performed in vitro. Twenty-four mature male New Zealand white rabbits, weighing 2.5-3.0 kg, were randomly selected. U-shaped defect of more than 50% of normal tendon in width and 8 mm in length was made in infraspinatus tendons of unilateral limb as the experimental group; the canine DTSs were used to repair defect, and the insertion of infraspinatus tendon on greater tuberosity of humerus was reconstructed in the experimental group. No treatment was done on the contralateral limb as the control group. At 4, 8, and 12 weeks after operation, the specimens were harvested for histological observation and biomechanical test. Results Histological examination showed that collagen fibers of canine DTSs were well preserved, without residual cells. The cytocompatibility examination showed that fibroblasts attached well to canine DTSs. Biomechanical test showed that the maximum load and stiffness increased significantly with time, and the maximum load and stiffness at 12 weeks were significantly higher than those at 4 and 8 weeks (P lt; 0.05). The maximum load and stiffness of the experimental group at 4 and 8 weeks were significantly lower than those of the control group (P lt; 0.05). The stiffness of the experimental group at 12 weeks was significantly lower than that of the control group (t= — 5.679, P=0.000), but no significant difference was found in the maximum load at 12 weeks between 2 groups (t=0.969, P=0.361). Histological observation showed that the control group displayed a 4-layer structure of the tendon-bone insertion. In the experimental group at 4 weeks, the tendon-bone interface was filled with granulation tissue, and a small amount of Sharpey’s fibers-like connected the tendon to bone; granulation tissue disappeared, and fibroblasts, Sharpey’s fiber, new cartilage, and chondrocytes significantly increased with time; tendon-bone interface became mature, but the tide line was not observed between the unmineralized fibrocartilage and mineralized fibrocartilage. Conclusion Canine DTSs prepared by repetitive freeze/thaw 5 times combined with nuclease processing for 12 hours, can enhance the healing of host tendon-bone and improve the biomechanical characteristics of the rabbit infraspinatus tendon.
Objective?To analyze the effect of different surgery techniques on the tendon-bone healing of rotator cuff insertion.?Methods?Forty-two adult Japanese rabbits, weighing 2.0-2.5 kg and male or female, were selected. Thirty-six rabbits were given a sharply left-lateral tenotomy of the supraspinatus tendon with subsequent re-attachment of the tendon. According to the depth of re-attachment, 36 rabbits were equally randomized into the cancellous-fixation group (a cancellous bed was prepared with a dental burr) and the cortical-fixation group (the same treatment was performed except the preparation of the bone bed). Six rabbits served as the controls without treatment (control group). At 4 and 8 weeks after operation, the general observation, HE staining, and the biomechanical test were performed.?Results?At 4 weeks after operation, the supraspinatus-humerus specimens morphologically showed atrophy and vague between tendon and new bone in the cancellous-fixation group and the cortical-fixation group; at 8 weeks, no obvious difference was observed between 2 groups and the control group. The histological results of the cortical-fixation group at 4 weeks revealed the interface between tendon and new bone became smooth. The interface became transitional at 8 weeks, and the shape of bone tissue was nearly normal. The interface obtained from the cancellous-fixation group at 4 weeks became sclerotic, and collagen fibers formed in disorder. With ingrowth of new bone and re-establishment of collagen-fiber continuity at 8 weeks, thickness of interface became thin, and bone tissue was remodeling. The ultimate load were significantly higher in the cortical-fixation group than in the cancellous-fixation group at both 4 and 8 weeks, and the results gained at 8 weeks is significantly higher than that at 4 weeks in each group (P lt; 0.05). Except rupture strength at 4 weeks between 2 groups and all tensile strength (P gt; 0.05), there were significant differences in the results of others (P lt; 0.05).?Conclusion?In this model, the tendon-bone healing process and the biomechanical properties of cortical-fixation is superior to those of cancellous-fixation.
Objective To investigate and compare the difference between two implants of reconstructing anterior cruciate l igament (ACL) for the early heal ing of implants tunnel interface in terms of biological mechanism. Methods Fiftyfive adult New Zealand rabbits weighing 2.0-2.8 kg were selected. Patellar l igament with tibia-bone block was obtained fromthe left knee joint serving as donor site, right knee joint served as the recipient site of autograft for ACL reconstruction. Thebone block end of implant was bone-bone interface heal ing model, while the l igament end was tendon-bone interface heal ing model. The general condition of rabbits was observed after operation, the gross observation and histology observation were conducted at 2, 4 and 8 weeks after operation (n=5), and biomechanics examination was conducted at 4 and 8 weeks after operation (n=20). Results Rabbits behaved normally after operation. The gross observation indicated that ACL had complete continuity and moderate tension during experiment. Histology observation: most part of bone-bone interface was connected by fibrous tissue, while the tendon-bone interface was mainly filled by granulation tissue 2 weeks after operation; most part of bone-bone interface was bone union, and there were osteogenesis reaction and large quantity of fibroblasts in the tendonbone interface 4 weeks after operation; complete bone union was evident in bone-bone interface, and the appearance of Sharpey fibers and the formation of indirect insertion occured in part of tendon-bone interface 8 weeks after operation. Biomechanics observation: the pull-out rate for tendon-bone interface and bone-bone interface 4 weeks after operation was 85% and 15%, respectively; while it was 95% and 5% 8 weeks after operation, respectively; indicating there was a significant difference between two groups (P lt; 0.001). Conclusion In the early stage after ACL reconstruction, bone-bone interface is better than tendonbone interface in terms of intensity and speed of heal ing.
To investigate the cl inical results and the mechanism of bone heal ing for the repair of bone defects following tumor resection with novel interporous TCP bone graft, and to test the hypothesis of “structural transplantation”. Methods From January 2003 to December 2005, 61 cases of various bone defects following the curettage of the benign bone tumors were treated with interporous TCP, with 33 males and 28 females, including bone fibrous dysplasiain 8 cases, bone cyst in 23 cases, eosinophil ic granuloma in 12 cases, enchondroma in 13 cases, non-ossifying fibroma in 2 cases, and osteoblastoma in 3 cases. Tumor sizes varied from 1.5 cm × 1.0 cm to 7.0 cm × 5.0 cm. The plain X-ray, single photon emission computed tomography (SPECT) and histology examination were obtained at various time points after operation. The in vivo biodegradation rate of the implanted TCP was evaluated based on a semi-quantitive radiographic analyzing method. Histopathology examination was performed in 1 revision case. Results All the patients were followed up for 5 to 24 months after operation. They all had good wound heal ing and bone regeneration. There was neither significant reverse reaction to the transplanted material nor locally inflammatory reaction in all of the cases. The bone defects were repaired gradually from 1 to 6 months after operation (bone heal ing at average 2.6 months after surgery) with a bone heal ing rate up to 96.7%. There was only 1 recurrence case (eosinophil ic granuloma in ischium) 3 months after operation. Given revision operation, this case gained bone heal ing. Radiographically, the interface between the implanted bone and host bone became fuzzy 1 month after implantation, indicating the beginning of new bone formation. Three months later, the absorption of the interporous TCP was noticed from peripheral to the center of the implanted bone evidenced by the vague or fuzzy realm. New bone formation could be seen both in peri pheral and central areas. Six months later, implanted bone and host bone merged together and the bone defect was totally repaired, with 78.9% degradation rate of the implanted TCP. Twelve months later, the majority of the implanted bone was absorbed and bone remodel ing was establ ished. In the cases that were followed up for 24 months, the function of affectedextremity was excellent with good bone remodel ing without recurrence. In 2 cases, SPECT showed that nucl ide uptake could be observed in implanted site and the metabol ic activity was high both in the central as well as the peripheral areas of the graft 1 month after implantation, which was an evidence of osteogenesis. Pathologically, the interporous TCP closely contacted the host bone inside the humerus 1 month after grafting. The interface between the implanted bone and host bone became fuzzy, and vascularized tissue began growing inside the implanted graft as a “l ining” structure. Conclusion The interporous TCP proves to be effective for cl inical reparation of bone defects following tumor resection. The inside three-dimensional porous structure simulates the natural bionic bone structure which is suitable for recruitment related cells in-growth into the scaffold, colonizing and prol iferation companied with the process of vascularize, finally with the new bone formation. The novel interporous TCP may boast both bone conductive and bone inductive activities, as an appeal ing “structural transplantation” bone graft.
Objective To explore the situation of tendon-bone heal ing when allogenic tendon graft is wrapped with autologous periosteum around the tendon in rabbits. Methods Twenty healthy New Zealand white rabbits with the age of 4-5 months were used in the experiment, weighing 2.5-3.0 kg. One-side posterior l imb was selected randomly as the test, and thecontralateral l imb was served as the control at the same time. The allogenic tendon graft was designed as a tendon-bone model in the proximal tibial metaphysis of rabbits. The portion of tendon in the bone tunnel was wrapped with autologous periosteal graft in which the cambium layer was facing the bone tunnel in the experimental group, while the portion of tendon in the bone tunnel was not wrapped with autologous periosteal graft in the control group. The histologic examination of the tendon-bone interface (n=2) and the biomechanical test for maximal pullout load (n=8) were conducted 4 and 8 weeks after operation, respec tively. Results All specimens were observed with naked eyes 4 and 8 weeks after the operation. Many new bones around bone tunnel outlet were seen in the experimental group, while a few or few new bones were seen in the control group. Four weeks after operation, histological observation showed there were a lot of prol iferative mesenchymal cells in the periosteal germinal layer in the experimental group and conspicuous membrane bone formation was obvious. The arrangement of massive osteoblasts around newborn bone trabecula was similar to pal isade. The newborn bone trabecula was l inked with the periosteum. Some loose connective tissues and few newborn bones between the tendon graft and the bone tunnel were seen in the control group, and the connection of them was loose. Eight weeks after operation, the connection between the tendon graft and the bone tunnel was tight and no gap existed in the experimental group. The number of newborn bones was large and their arrangement was relatively regular. The tidemark l ine was seen between the tendon graft and the bone tunnel, which was similar to normal tendon-bone interface. The prol iferation of fibroblast was active in the periosteum, and there were many fibrous joints betweenthe periosteum and the tendon graft. Partial bone formation was seen between the tendon graft and the bone tunnel in thecontrol group, with disorderly arrangement, and there were many collagen fibrous joints between the tendon graft and the bone tunnel. Four and 8 weeks after operation, the pullout or pull and break loads of the experimental group were (35.03 ± 1.21) N/ cm and (42.36 ± 1.31) N/cm, respectively, and those of the control group were (26.14 ± 6.13) N/cm and (31.63 ± 6.87) N/ cm, respectively. There was significant difference between the two groups (P lt; 0.05). Conclusion The transplantation of autologous periosteum graft wrapping around allogenic tendon graft may shorten the time of osteochondral ossification between the tendon graft and the bone tunnel, improve heal ing strength and promote tendon-bone heal ing in the bone tunnel in rabbits.
OBJECTIVE: To investigate the styles and affecting factors of bone union after massive frozen allografting for skeletal reconstruction owing to excision of bone tumor. METHODS: From 1992 to 1999, 85 patients suffering from bone malignant tumor were given the excision of large bone segment and treated with allografting in different methods of operation: large bone allografts with condylar articular surface in 16 cases, osteoarticular allografts in 57 cases, bone allografts in combination with prosthetic replacement of hip in 9 cases, and prosthetic replacement of knee in 3 cases. The average follow-up was 2 years and 9 months. The union time and styles of host-donor junction were determined by X-ray characters, and the results of operations were assessed according to Enneking’s functional evaluation system of reconstructive procedures after surgical treatment of tumors for the musculoskeletal system. RESULTS: There were 4 kinds of basic bone union styles by the X-ray characters, there were no significant difference in the time span of bone union after fixation with different methods. Of the 85 fresh-frozen allografting procedures, more than 80% of the patients were treated with interlocked intramedullary nail and allograft-prosthesis combination, and the overall result was excellent and good. Sufficient blood supply was important for host-donor junction healing, but the function of immune response was uncertain. CONCLUSION: There were different styles of bone union after massive allografting. The recommended operative methods for massive allografts are stable internal fixation, sufficient blood supply, soft tissue repair and periosteal flap coverage.
Objective To observe the effect of vascular endothelial growth factor (VEGF) in fracture healing and to investigate the influence of VEGF and VEGF antibody in fracture healing. Methods One hundred and five rabbits were used tomake fracture model in the left radius and randomly divided into control group,VEGF group and VEGF antibody group. VEGF and VEGF antibody were used in the VEGF group and VEGF antibody group respectively, then the blood flow of the fracture ends was measured by single photon emission computed tomography (SPECT) 8,24 , 72 hours, 1, 3, 5 and 8 weeks after fracture, the X-ray films of the fracture sites were taken after 1, 3, 5 and 8 weeks to observe the fracture healing. Results The blood flow of the fracture ends in the VEGF groupincreased during aperiod from 8h to 3wk after fraction when compared with that of the control group, and no obvious difference was seen on the X-ray films between the two groups. In the VEGF antibody group, the blood flow of the fracture ends decreased obviously when compared with that of the control group. The fracture healing processwas interfered seriously and nonunion change was seen in the fracture site. Conclusion The lack of VEGF will interfere with the fracture healing process and result in nonunion in the fracture site. Administration of ectogenous VEGF may promote fracture healing by increasing the blood flow of the fracture ends.
OBJECTIVE: To investigate the effect of decalicified dental matrix (DDM) on healing of traumatic fracture and its side-effect. METHODS: From June 1997 to December 1998, 42 patients with closed traumatic long bone fracture (36 males and 6 females, aged from 18 to 57 years with an average of 32 years) were divided into two groups randomly; open reduction and internal fixation were carried out in all patients, but the DDM was used only in experimental group. After operation, the body temperature, ALT, and bone union time were observed and recorded. RESULTS: Following-up 1 to 3 years, the bone union time of experimental group was significantly shorter than that of control group (P lt; 0.01), there was no significant difference in the temperature and ALT changes between two groups(P gt; 0.05). No infection occurred. CONCLUSION: DDM can promote the growth of bony callus and enhance the healing of fracture. There is no side-effect.
OBJECTIVE: To observe the difference of the fracture reparation using autogeneic-iliac bone and allogenic bone. METHODS: Comminuted fracture of humerus in two sides were made in rabbits. Autogeneic-iliac bone was implanted in one side, while allogenic bone of equal capacity was implanted in the other side. General observation, X-ray, and HE histologic section were done when the rabbits were put to death in different stages. RESULTS: One week after implantation, the graft had been enclosed by connective tissue without infiltration of the inflammatory cells. At the 2nd week, the graft had been enclosed in osteoplastic granulation tissue, and the cartilage callus had formed. At the 3rd week, there had been broken sequestrum among the callus; the cartilage had actively formed the bone; and the medulla had been making. At the 4th week, the sequestrum had disappeared, and the mature callus had appeared; the osteoblasts had arranged in a line around the edge of the mature callus. At the 5th week, the callus was b, compact and approached mature bones. At the 6th week, there had been the compact lamellar structures and the complete haversian’s systems. There was no significant difference between callus of two sides by using image quantitative analysis in the 3rd, 4th week (P gt; 0.05). CONCLUSION: The allogenic bone has good histocompatibility and bone conduction effect, and can be used for bone transplantation substitute with autogenous-iliac bone.