The management of transarticular fractures is still a difficult clinical problem. Owing to the shape memory effect and its special design,the shape memory com- pression staple could fulfill nearly all the special treatment requirement of the trans- articular fractures.Early bone union and 93.5% satisfactory function restoration were obtained in the series of 121 cases.Stable fixation,early functional exercise and continuous compressive force produced by the staple are the mainofactors contri- buted to the good results.

Objective To observe the ultrastructural alteration and healing characteristics of osteoporotic fracture, and to elucidate its cellular mode of healing. Methods Eighty female SD rats of 8 months old, which had the weight of 290 to 340 g, were randomized into two groups of 40 each: the osteoporotic fracture model(OPFM) and the common fracture model(CFM). After anesthesia, the bilateral posterior transperitoneal approach was performed in the OPFM group and the bilateral ovaries were removed; and in the CFM group, only the sham operations were performed. Three months later, the fracture of femoral middle shaft were created and fixed with a Kirschner pin through medullary cavity. The callus of each rat was examined by transmission electron microscopy(TEM) and scanning electron microscopy(SEM) in 5 days and 1, 2, 4, 6, 8, 12 and 16 weeks postoperatively. Results TEM showed that the number of chondrocyte in OPFM group was greater, but function was lower than that of CFM group. Volume of collagen secreted by the chondrocyte was less and arranged irregularly during the fracture healing period in OPFM group. Number and function of osteoblasts in OPFM group were lower than that of CFM group. Extracellular collagen was disordered and sparse, but function of osteoclasts in OPFM group was more active than that of CFM group. The SEM showed that the collagen in callus of CFM group was dense and arranged in good order or pyknotic. Conclusion The fracture healing of the osteoporotic fractures is due to the decrease of the osteoblastic formation and the increase of the osteoclastic resorption as well as the poor bony healing quality.

Objective To i nv estigate the clinical effect of shape-memory sawtooth-arm em bracing fixator in the management of periprosthetic femoral fracture.Methods Since1994, 21cases of periprosthet-ic femoral fractures had been treated in7hospitals with the shape-memory sawtooth-arm embracing fixator designed and developed b y the Ninth Peoples Hospital,Shanghai Second Medical University(SSMU ).Of the21cases,12were males and9were females,aging from42to83years old. Eighteen of the series ex peri-enced periprosthetic fracture at2weeks to10y ears after joint replacement the fractures were found as oblique,spi ral or comminuted with the fracture lines located between the lesser trochanter and a p oint 5cm distal to the end of prosthetic stem.The other three were revision c ases,in which2cases with osteoporosis had intraoperative spiral fracture and1 case had long segmental osteotomy for removal of the prostheses.One of the 21patients had Z-shaped femoral osteotomy,while the other20cases were clas sified into Jo hannson typeⅠfrac ture in4cases,typeⅡ9cases and typeⅢ7case s.All of them were complete fracture with dis-placement.In practice,the arm s of fixator were expanded firstly by immersing into the ice water to make the tempera ture of the device decrease to4~7℃.After reduction of the fracture ,the body of the fixator was placed on the tensile side of the femur,and th e temperature of the arms was raised with hot saline.With its shape memory ef fect,the sawtooth-arms began to close up and grasped the fracture fragments ti ghtly.Results Surgical process in all of the cases was smoothly done:the frac tures were stable after the fixation,and no ex-ternal fixation was required po stoperatively,except four cases underwent skin traction of the affected lim b for 2weeks.All the patients were able to walk with two crutches at2to4we eks after the operation.The post-operative follow-up lasted from1to7years, and no fracture re-displacement was found.The results of frac-ture healing were good while the functional recovery to the pre-operative level was achieved in the all se ries.Conclusion For periprosthetic femoral fracture,shape memo ry sawtooth-arm embracing fixator is a re liable device being implanted easily and offering stable fixation;it should be the treatment method of the first choice.

Objective To observe the expression of platelet-derived growth factor A(PDGF-A) and PDGF-?R in callus during osteoporotic fracture healing and to explore further into the mechanism or effect of PDGF-A and PDGF-?R on osteoporotic fracture healing. Methods The expression and change of PDGF-A and PDGF-?R in different period of osteoporotic fracture healing(5, 7, 14, 28, 42 days) were investigated by means of immunohistochemistry(ABC method). Results There were different cells origin (chondrocyte, osteoblast, osteocyte, vascular endothelial cell, et al) and degree of expression of PDGF-A and PDGF-?R in callus during different period of osteoporotic fracture healing. Conclusion PDGF-A moderates and participates in osteoporotic fracture healing. The decrease of osteoporotic fracture repair capacity may correlate with abnormality of PDGF-A secretion.

Objective To investigate if the physician's attending could improve the compliance of knee osteoarthritis patients with community exercise therapy.Methods The Questionnaire of Community Rehabilitation of Musculoskeletal Disorder was developed.The knee osteoarthritis patients with or without physicians' attending were surveyed anonymously 3 month after exercise.Results The incidence of compliance in exercise was 87.65% in patients with the physicians' attending,and 70.37% without attending(P<0.05).Conclusion The physicians' attending may improve the compliance of knee osteoarthritis patients in community exercise therapy.

Objective　To explore the influence of stress-relaxation plate(SRP) fixation on the remodeling of cortex under plate. Methods　Twenty-eight New Zealand rabbits were used in this study, the bilateral tibia were osteotomized in the middle and fixed with SRP (experimental group) and rigid plate (control group) respectively. The scanning electron microscopy was used to observe the bone remodeling process from 2 to 48 weeks after operation. Results　There was cortex osteoporosis beneath plate in different degree in both experimental and control groups before 8 weeks, it showed as the disorganization of collagen fiber structure and formation of resorption cavities. In comparison, the osteoporosis degree in experimental group showed milder than that of the control group. After 12 weeks, the resorption cavities became smaller, and the structure of collagen fibers became regular with the alignment parallel to the long axis of cortex. In contrast to the experimental group, the bone osteoporosis under plate of control group exacerbated continuously. Conclusion　Without removal of the bone plate, SRP fixation not only reduce the degree of plated bone osteoporosis, but also make the osteoporosic bone return to normal.

Objective To analyze the practical experiences of design and its clinical application of custom-made tumor prostheses of knee. Methods A retrospective study of 41 cases of distal femur or proximal tibia tumors treated surgically from June 1999 to October 2002, was carried out. In the study, there were 29 males and 12 females aging from 11 to 69 years with an average of 35.0 years. The location of tumors were at distal femur in 23 cases and 9 cases at proximal tibia, of which 15 were osteosarcoma, 13 giant cell tumor, 3 chondrosarcoma, 5 solitary metastatic bone tumor, and 1 each of fibrosarcoma, malignant fibrohistocytoma, Ewings sarcoma, small round cell sarcoma and syndesmofibroma. The custom-made semi-constrained knee prosthesis with femoral or tibial component was implanted after extra-capsular resection of the tumor bone segment. A special femoral component with elongated construction was used in an 11-year old case for further femur lengthening. Resection of femoral artery involved by tumor and reparation by great saphenous vein was performed in one case. Results The operations of the 41 cases were all smoothly performed. 33 cases were followed up from 8 to 37 months with an average of 20.2 months. The daily life ability was recovered in 3 months after the operation. Among them, no loosening or failure of the prostheses was found, and local recurrence was found in 2 cases and distant metastasis in 3 cases. The design of knee prosthesis could provide some proper internal/external rotation and adduction/abduction movements accompanying with the flexion and extension of the knee joint without affecting the stability of the joint. For the case of proximal tibia tumor, a special design and surgical technique was developed to provide the reconstruction of patellar ligament insertion with rather good results; and the recovery of knee extension and stability were satisfied. Conclusion The custom-made semi-constrained tumor prosthesis of knee could be used as an effective method for the limb-savage management either the distal femur or proximal tibia tumor cases.

Objective To evaluate effectiveness of bone marrow derived mesenchymal stem cells(BMSCs) transduced by adenovirus mediated human bone morphogenetic protein-2 (Adv-hBMP-2) gene in the repair of diaphysic segmental bone defects of goats. Methods The tibial bone defects (2.1 cm) of 22 goats, who weighted from 18.1 kg to 29.5 kg, were established and divided into 4 groups: groupⅠ, Adv-hBMP-2 transduced BMSCs group (n=8); groupⅡ, adenovirus mediated ?-galactosidase(Adv-?gal)gene transduced BMSCs group (n=6); groupⅢ, non-transduced BMSCs group (n=6); groupⅣ, untreated group (n=2). Roentgenography, histomorphometrical analysis and biomechanical measurement were studied at various times. Results Roentgenography showed more callus in the bone defect site of group Ⅰ. At 24th week after implantation, the healing rates of group Ⅰ,Ⅱ,Ⅲ, and Ⅳ were 6/7, 1/5, 2/5, and 0/1 respectively. There was statistic significant difference of X-ray grading between groupⅠand groupⅡor Ⅲ. Histomorphometrical analysis showed much more total new trabecular bone area (TBA) of groupⅠthan that of other groups. Biomechanical strength of groupⅠwas superior to that of groupⅡand Ⅲ. Conclusion Adenovirus mediated BMP-2 gene transferred BMSCs can repair segmental bone defect in goat without osteoconductive scaffold.

Objective To investigate the rejection mechanisms of bone grafts by comparing the immune reaction of xenografts versus allografts, and the influence of IL-4 and IL-10 on immune responses. Methods Twenty C57BL/6 mice and 1 New Zealand rabbit were used as transplant donors for allografts and xenografts, respectively. One hundred BALB/c mice were used as transplant recipients and randomly divided into 5 groups. Using a model of the muscle pouch for implantation, the immune reactions of bone allografts and bone xenografts were studied through observing the lymphocyte responses of the stimulating index of lymphocytes from the mixed lymphocyte culture (MLC), subsets of lymphocyte, cytokinetic and histological findings in 1, 2, 4 and 6 weeks after implantation respectively. Results Xenograft rejection was rapid (1 week) and stronger than allograft rejection (P

Objective To summarize the experience in CAD / CAM custom-made hemipelvic prosthesis and its application in 8 patients. Methods The exact model of pelvis was generated with its CT data by Rapid Prototyping Technique (RPT). Simulated bone resection and prosthesis design were performed on the models. The prosthesis should be fixed simultaneously on the contralateral pubic ramus (or the remainder of pubis), the joint facet of sacrum (or the remainder of ilium) and on the remained ischium if part of it could be preserved. When prosthesis was put in place, the acetabular component should be symmetric with the contralateral acetabulum in terms of the height, lateral distance and abduction angle, after it's fixation on the remained pelvis with cancellous screws, bolts and hooks, conventional total hip implants with cemented acetabular and cementless femoral prothesis were implanted. 8 patients underwent this kind of procedure, of them 7 suffered from large pelvic tumor, including 2 chondrosarcoma, 3 giant cell tumors, 1 cartilaginous fibrodysplasia and 1 metastasis. One patient received this procedure for severe osteolysis after THA. Tumor artery embolization was done in 6 of them 24-48 h before operation. Results Blood transfusion was 4971 ml in average. The implantation of prosthesis was easily accessible. One suffered from remained sinus, and healed after myocutaneous flap transferring. All patients began non-weight bearing walk with double crutches 6 weeks after operation and gradually abandoned crutches in 3 months. One patient with chondrosarcoma died of lung metastasis 9 months after operation. No loosening was found during the 1 to 4 years (2.5 years in average) follow-up of the 7 cases. The position of bilateral hips was symmetric. They all recovered to self-care. Two of them returned to work 7 and 8 months after operation respectively. One local recurrence happened and was resected again. Conclusion The custom-made hemipelvic prosthesis generated with RPT and CAD/CAM can improve the prosthesis fixation, ensure the exact orientation of acetabular component and make the operation easy.