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Elucidation of the signaling pathway mechanisms related to the mechanical stress-mediated bone regeneration is of great significance for improvement of bone regeneration and clinical treatment of bone-related diseases such as bone defects and bone elongation. Mechanical stress transmits mechanical stimuli into cells through the piezo channels and integrins, causing a variety of signaling pathway responses, which in turn changes transcription factor translocation, gene expression, and osteoblast differentiation to promote bone regeneration ultimately. This article reviews the research progress concerning the mechanisms related to mechanical stress-mediated bone tissue regeneration.
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Objective:To investigate the clinical effects and indications of tibial condylar valgus osteotomy (TCVO) in treating varus unicompartmental knee osteoarthritis.Methods:A retrospective analysis was conducted in 32 patients (45 knees) who suffered from varus unicompartmental knee osteoarthritis and underwent TCVO from June 2016 to June 2018. These patients were aged 65.8±8.3 (range from 52 to 79) years, including 12 males (18 knees) and 20 females (27 knees). All enrolled individuals presented obvious expansion of the lateral joint space with joint line convergence angle (JLCA) of 7.19°±2.69°. Based on the full-length standing X-ray imaging of the lower limbs at before and 2 years after surgery, the percentage of mechanical axis (%MA), femorotibial angle (FTA), hip-knee-ankle angle (HKA), lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA) were measured and analyzed to evaluate the improvements of lower extremity alignments. The medial tibial plateau depression (MTPD), posterior proximal tibial angle (PPTA), JLCA and joint space width (JSW) were measured and analyzed to evaluate the congruency of the knee joint and shape of the tibial plateau based on positive and lateral radiographs of knee joint. In addition, visual analogue scale (VAS) and Western Ontario and McMaster Universities (WOMAC) score were evaluated to assess the clinical effects of TCVO pre-operatively and at 1 year or 2 years after surgery.Results:All patients were followed up for 33.4±7.4 (range from 25 to 40) months. Comparing to the preoperative radiological data, %MA at 2 years after surgery increased from 3.78%± 14.34% to 66.16%±9.90%, FTA from 185.41°±4.45° to 170.81°±2.87°, HKA from 169.69°±1.70° to 181.16°±2.39°, MPTA from 83.03°±3.20° to 90.84°±3.67° all with statistical significance ( P<0.05). There was no significant difference for PPTA between before (89.22°±1.52°) and 2 years (88.97°±1.57°) after surgery ( t=0.638, P=0.526). MTPD improved from -7.81°±3.27° to 5.78°±2.19° ( t=19.218, P<0.001). However, there was no significant difference for PPTA between before (81.63°±3.28°) and 2 years (82.25°± 2.21°) after surgery ( t=0.881, P=0.382). JLCA reduced from 7.19°±2.69° to 0.22°±2.09°. The medial and lateral JSW were corrected from 2.45±0.23 mm and 5.86±0.25 mm to 3.73±0.27 mm and 4.68±0.34 mm ( P<0.05), respectively. Additionally, VAS and WOMAC scores improved from 6.46±2.21 and 52.66±16.69 preoperatively to 2.94±1.72 and 19.31±14.87 at 1 year after surgery, and to 1.39±1.45 and 13.66±15.44 at 2 years after surgery, respectively ( P<0.05). Conclusion:Satisfactory early therapeutic outcomes could be achieved by TCVO in varus unicompartmental knee osteoarthritis with subluxated lateral joint and increased JLCA. TCVO can correct intra-articular varus deformity, adjust mechanical axis and relieve knee joint pain and dysfunction.
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The process of bone healing is absolutely complicated and affected by a wide variety of factors. The quality of bone healing directly determines management approaches. Therefore, it is crucial to evaluate accurately outcomes of bone healing. The assessments of bone healing mostly used in current clinical practice are a combination of clinical manifestations and X-ray examination while computed tomography (CT) and ultrasound may be applied alternatively for particular parts and populations. As understanding of bone healing process and bone biomechanical structure is deepening in recent years, both traditional and novel assessments of bone healing have been well refined. This review will expound on the advantages, disadvantages and clinical indications of various assessments, as well as their future development trends, to provide useful information for clinicians.
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Over the past several decades of innovation and development, Ilizarov technique has been widely recognized and applied in correction of limb deformity and post-traumatic sequelae with outstanding clinical outcomes, which making remarkable contributions to the development of orthopaedics. There is no doubt that tissue regeneration induced by tension-stress is the core of Ilizarov technique, and a series of biological cascades contributing to tissue regeneration could be triggered by mechanical stimulation through signal transduction including bone morphogenetic proteins regulations, inflammatory responses and immune responses, angiogenic activities, stem/progenitor cell homing and other systematic effects. One of main limitations of Ilizarov technique is slow rate of new bone mineralization. To facilitate this technique application better in clinical practices, a multitude of researches of means for promoting bone mineralization have become hot spots in this field in recent years, such as physical measures, chemicals and biological therapies. With better understanding of distraction histogenesis for promoting tissue regeneration, transverse tibial bone transport has been increasingly applied to vascular disease management in lower extremity, such as diabetic foot and thromboangitis obliterans. This review focuses on the recent advances in understanding the basic biological mechanisms of Ilizarov technique and new methods for promoting bone consolidation in distraction areas, providing evidence and ideas for further mechanism investigations and approach innovations.
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Professor Zhang Yingze, an academician of Chinese Engineering Academy, has dedicated himself to clinical medicine, scientific research and education in orthopedics for over 4 decades. In recent years, Professor Zhang, together with his research team, has made marvelous breakthroughs in various aspects of traumatic orthopedics which he is trying to put into practical transformation. The significant innovations of Professor Zhang and his colleagues include (1) establishment of an epidemiologic system for Chinese traumatic orthopedics, (2) proposal of new types of fractures, e.g., spiral tibial shaft fracture associated with posterior malleolar fracture, (3) introduction of fibular osteotomy for knee osteoarthritis and (4) new diagnosis and treatment approaches for pelvic and acetabular fractures. This paper is to discuss the academic thoughts of Professor Zhang, hoping to inspire young Chinese traumatic orthopedists to devote themselves to scientific innovations.
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Type H endothelial cells (CD31 hiEMCN hi), a special subtype of vascular endothelial cells, are distributed mainly in endosteum and long bone metaphysis. They recruit and activate osteoprogenitor cells and promote endochondral ossification through paracrine, thereby promoting osteogenesis. On the contrary, their biological activities can be regulated by osteoclasts and osteoblasts. At the same time, the mutual regulation of type H endothelial cells is also closely related to the process of angiogenesis and osteogenesis. This article reviews the characteristics and cytokine expression profiles and the mediating role in mutual regulation of angiogenesis and osteogenesis of the cells, offering an insight for establishment of a bone regeneration strategy based on the coupling of angiogenesis and osteogenesis.
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Objective:To explore the reliability of preoperative diagnosis of low-grade infectious nonunion using haematological testing and radioisotope scanning (bone 3-phase image).Methods:A retrospective study was conducted of the 265 patients with bone nonunion who had been treated at Department of Orthopaedics, The Sixth People’s Hospital Affiliated to Shanghai Jiaotong University and at Department of Orthopaedics, The Eighth People’s Hospital Affiliated to Shanghai Jiaotong University from June 2010 to June 2018.They were 151 males and 114 females, aged from 19 to 64 years (average, 39.7 years).The nonunions occurred mainly at the tibia (113 cases) and the femur (72 cases).The preoperative results of their white blood cell count (WBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and radioisotope scanning were recorded.Taking the intraoperative pathological observations as the gold standards, the sensitivity, specificity, area under curve (AUC) of receiver operator characteristic (ROC) and Youden index were statistically analyzed respectively for every preoperative haematological tests and radioisotope scanning as well as for different combinations of the radioisotope scanning and one or more haematological tests.Results:Compared with the pathological observations, the radioisotope scanning showed a sensitivity of 80.7%, a specificity of 73.3%, an AUC of 0.770 and a Youden index of 0.540.In the combinations of radioisotope scanning and one haematological test, that of radioisotope scanning and CRP produced the largest AUC of 0.683, a sensitivity of 98.0%, a specificity of 70.3%, and a Youden index of 0.848.In the combinations of radioisotope scanning and 2 haematological tests, that of radioisotope scanning and WBC and ESR produced the largest AUC of 0.895, a sensitivity of 94.3%, a specificity of 67.3%, and a Youden index of 0.616 and all the 3 ones yielded an AUC of more than 0.880.The combination of radioisotope scanning and all the 3 haematological tests produced a sensitivity of 96.5%, a specificity of 79.7%, an AUC of 0.925 and a Youden index of 0.762.Conclusion:Combination of haematological testing and radioisotope scanning can be a reliable preoperative diagnosis of low-grade infection nonunion.
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Objective:To discuss the key technique and strategy in the treatment of humeral shortening complicated with proximal deformity using a monorail external fixator.Methods:We retro-spectively reviewed 10 patients (8 males and 2 females) with humeral shortening and proximal deformity who had been treated by a monorail external fixator between March 2015 and April 2018.Their mean age was 19.6 years (range, from 15 to 27 years).The humeral shortening was complicated with proximal varus in 8 cases, and with proximal varus plus kyphosis in 2.The affected humeri were 6 to 11 cm (mean, 8.5 cm) shorter than the normal ones.Half-pins were placed onto the lateral upper arm for installation of a unilateral external fixator to correct the proximal humeral deformity immediately after proximal osteotomy.Gradual lengthening was performed after osteotomy in the middle humeral shaft.The limb function was evaluated by the Cattaneo cri-teria.Results:All patients were followed up for 15 to 41 months (mean, 20 months).The length of lengthening ranged from 5 to 12 cm (mean, 7.5 cm).The range of shoulder abduction averaged 160° (from 130° to 180°), much improved than the preoperative average value (90°).Fine ossification was observed in the lengthening part in 9 patients but dysostosis in the lengthening part occurred in one patient who was healed after iliac autografting.No such complications as pin tract infection and radial nerve injury occurred.Ac-cording to the Cattaneo criteria, 9 limbs in 8 cases were excellent and 2 cases good.Conclusions:A monorail external fixator is a reliable choice for treatment of humeral shortening complicated with proximal deformity.To obtain satisfactory clinical effects, it is essential to master the installation technique of external fixator and prevent and control complications as well.
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Objective@#To study the effect of growth differentiation factor (GDF) 11-silenced bone marrow stromal cells (BMSCs) on bone regeneration in early steroid-induced osteonecrosis of the femoral head in rats.@*Methods@#After GDF11 expression in BMSCs was inhibited by siRNA, the knockdown efficiency and transfection cytotoxicity were detected. The further experiments both in vitro (n=3) and in vivo (n=8) were divided into 4 groups respectively: blank control group (without any intervention), model group (glucocorticoid treatment), experimental group (siRNA transfection and glucocorticoid treatment) and negative control group (negative control transfection and glucocorticoid treatment). The BMSCs were induced into osteogenic differentiation. Alkaline phosphatase (ALP) staining and alizarin red staining were applied to evaluate the osteogenic differentiation ability of the cells while reverse transcription polymerase chain reaction (qRT-PCR) was employed to detect the relative expression levels of osteogenic markers. The osteogenesis in the necrotic femoral head was evaluated by microCT, H&E staining, immunohistochemistry staining and biomechanical test.@*Results@#No transfection cytotoxicity was found (P>0.05). The ALP staining and alizarin red staining showed that the osteogenic differentiation of BMSCs in the experimental group was better than that in the model group. At the level of mRNA, the relative expression of ALP, runt-related transcription factor (Runx) 2, osteocalcin (OCN) and type Ⅰ collagen (α1) (COL1A1) in the blank control group (1.00±0.09, 1.02±0.23, 1.03±0.30 and 1.02±0.25, respectively) were significantly higher than those in the model group (0.46±0.11, 0.50±0.11, 0.35±0.01 and 0.57±0.02, respectively) but significantly lower than those in the experimental group (1.97±0.30, 0.94±0.19, 1.50±0.18 and 1.28±0.37) (all P<0.05). MicroCT images and quantitative analysis showed that the bone mass in the experimental group was significantly increased compared with the model group (P<0.05). Histological examination showed better bone regeneration and higher expression of Runx2 and COL1 in the necrotic femoral head in the experimental group than in the model group. Improved biomechanical properties were shown in the experimental group compared with the model group (P<0.05).@*Conclusions@#Silence of GDF11 expression may alleviate the inhibitory effect of glucocorticoid on osteogenic differentiation of BMSCs. Early transplantation of GDF11-silenced BMSCs may promote osteogenesis in the necrotic femoral head in rats.
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Objective To study the effect of growth differentiation factor (GDF) 11-silenced bone marrow stromal cells (BMSCs) on bone regeneration in early steroid-induced osteonecrosis of the femoral head in rats.Methods After GDF11 expression in BMSCs was inhibited by siRNA,the knockdown efficiency and transfection cytotoxicity were detected.The further experiments both in vitro (n =3) and in vivo (n =8)were divided into 4 groups respectively:blank control group (without any intervention),model group (glucocorticoid treatment),experimental group (siRNA transfection and glucocorticoid treatment) and negative control group (negative control transfection and glucocorticoid treatment).The BMSCs were induced into osteogenic differentiation.Alkaline phosphatase (ALP) staining and alizarin red staining were applied to evaluate the osteogenic differentiation ability of the cells while reverse transcription polymerase chain reaction (qRT-PCR) was employed to detect the relative expression levels of osteogenic markers.The osteogenesis in the necrotic femoral head was evaluated by microCT,H& E staining,immunohistochemistry staining and biomechanical test.Results No transfection cytotoxicity was found (P ＞ 0.05).The ALP staining and alizarin red staining showed that the osteogenic differentiation of BMSCs in the experimental group was better than that in the model group.At the level of mRNA,the relative expression of ALP,runt-related transcription factor (Runx) 2,osteocalcin (OCN) and type Ⅰ collagen (α1) (COL1A1) in the blank control group (1.00 ± 0.09,1.02 ± 0.23,1.03 ± 0.30 and 1.02 ± 0.25,respectively) were significantly higher than those in the model group (0.46±0.11,0.50±0.11,0.35±0.01 and0.57±0.02,respectively) but significantly lower than those in the experimental group (1.97±0.30,0.94±0.19,1.50±0.18 and 1.28 ±0.37) (all P ＜ 0.05).MicroCT images and quantitative analysis showed that the bone mass in the experimental group was significantly increased compared with the model group (P ＜ 0.05).Histological examination showed better bone regeneration and higher expression of Runx2 and COL1 in the necrotic femoral head in the experimental group than in the model group.Improved biomechanical properties were shown in the experimental group compared with the model group (P ＜ 0.05).Conclusions Silence of GDF11 expression may alleviate the inhibitory effect of glucocorticoid on osteogenic differentiation of BMSCs.Early transplantation of GDF11-silenced BMSCs may promote osteogenesis in the necrotic femoral head in rats.
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Objective To evaluate the outcomes of distraction osteogenesis with mini external fixation in management of metacarpophalangeal bone defects after hand trauma.Methods From June 2010 to December 2015,16 patients with metacarpophalangeal bone defects after hand trauma received distraction osteogenesis at our department.They were 11 men and 5 women,from 20 to 45 years of age (average,32.5 years).There were altogether 20 bone defects:8 cases had single metacarpal bone defect,2 unilateral second and third metacarpal bone defects and 6 phalangeal shortening after repair of digital stump (involving thumb in 4 cases,index finger in one and index and middle fingers in one).The metacarpophalangeal bone defects averaged 1.8 cm (from 1.0 to 3.1 cm).Under the fluoroscopic guide,4 or 6 mini half-pins in one line were directly drilled into the dorsal aspect of the involved metacarpophalangeal bone before the Orthofix fixator was mounted.The proximal (18 digits) or distal (2 digits) osteotomy between the second and third pinholes was performed via the dorsal approach,The external fixator and pins were removed without anesthesia after callus maturation.Results Average follow-up period was 12.2 months (range,from 9 to 26 months).All the metacarpal bone defects were reconstructed and all the phalangeal shortenings were lengthened;the bony callus was completely calcified at the lengthened part.The mean lengthening was 1.9 cm (from 1.0 to 3.1 cm);the percentage of lengthening ranged from 26％ to 51％ (average,34％).The bone lengthening index (time cost by average 1 cm) was 70.9 d/cm (from 60.0 to 87.1 d/cm).According to the Tentative Assessment Criteria for Upper Extremity Function by Hand Surgery Society,Chinese Medical Association,the total activity of motion (TAM) was excellent in 13 cases,good in 4,fair in 2,and poor in one,yielding an excellent to good rate of 85.0％.Conclusion Distraction lengthening using mini external fixation is a valid option with a minor rate of complications which allows for early functional exercise to help restore the appearance and function of the affected fingers.
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Objective To explore the effect and mechanism of local administration of thymosin β4 (Tβ4) on bone regeneration in a distraction osteogenesis model of rat fenur.Methods Sixty Sprague-Dawley rats were randomly divided into groups A,B and C in this study.A distraction osteogenesis model was established in the left femur after osteotomy.At the end of distraction period,the bone regeneration area in group A was subjected to no treatment,that in group B to injection of phosphate buffer saline (PBS),and that in group C to injection of Tβ4.On days 22,29 and 43 postoperatively,the rats from each group were randomly sacrificed and processed for observation of bone regeneration in the distraction osteogenesis area using radiography,Micro-CT,histology and immunohistochemical staining.RT-PCR was used to detect the expression of related genes as well.Results Radiography revealed that the bone regeneration in group C was superior to that in groups A and B on days 22,29 and 43 postoperatively.Micro-CT examination showed significantly increased bone volume (BV),bone mineral density (BMD) and ratio of bone volume to tissue volume (BV/TV) in group C on days 22,29 and 43 postoperatively,and significantly decreased ratio of bone surface area to bone volume on postoperative day 43 in comparison with groups A and B(P ＜ 0.05).HE staining indicated that local capillary density was significantly higher in group C than in groups A and B after local administration of Tβ4 in the distraction osteogenesis.Immunohistochemical staining showed that the capillary density and osteoblasts in group C were higher than in groups A and B.RT-PCR results revealed significantly higher expression of eNOS and Osterix mRNA in the local callus in group C on postoperative day 22 than in groups A and group B (P ＜ 0.05).Conclusion Local administration of thymosin β4 may promote bone formation,which is probably related to the increased expression of eNOS and Osterix.
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Objective To evalute the effect of Ilizarov technique in the treatment of hypertrophic nonunion.Methods Form June 2008 to December 2010,12 patients with hypertrophic nonunion were treated with Ilizarov technique,including 10 males and 2 females with an average age of 46.5 years.The pathology sites of nonunion were kept as closed as possible without any bone graft during operation.As to patients who had ever been treated with plate or intramedullary nail,the hardware should be removed by minimal invasive approach.These procedures aimed to keep the vascularity of nonunion site intact.Ilizarov apparatus were preoperatively constructed.Distal segment and proximal segment of nonunion were mounted respectively with two external circle using the smooth wires and half pins.The two-circle stabilizing one segment was nominated with transosseous modules.Distal module and proximal one was connected with a pair of axial hinges.The pathology sites were gradually distracted from the seventh day postoperatively,0.25 mm/d.Accompanying with deformity correction,limb length discrepancy (LLD) also were restored simultaneously.Then,all the screws and nuts in the apparatus should be tightened,which was favourable to the callus consolidation.Results All 12 cases of nonunion healed without any bone graft.The fixator wearing time lasted 6-12 months,with an average of 8 months.Correction of deformity and LLD were achieved.The average lengthening was 3.0 cm (range,2.0-5.5 cm),the average correction angle was 23° (range,10°-30°).After 6-18 months follow-up,all the patients restored satisfactory function.Conclusion Hypertrophic nonunion can be treated successfully with Ilizarov technique.The key of successful callus distraction is strictly identifying the indications.
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Objective To explore the methods of Y-V vascular pedicle lengthening technique for cover-age of the defect of great toe after wrap-around flap transfer, and decrease the morbidity of donor site in great toes. Methods Fifteen patients received three kinds of flap for immediate resurfacing of donor defect of the great toes during wrap-around flap transfer, all flaps were harvested with Y-V vascular pedicle lengthening technique. Among them, 9 cases received the free lateral tarsal flaps transplantation for coverage of defect in donor great toes, 5 cases was repaired by medial tarsal flaps, and only one was treated by the medial plantar flap. Results All the flaps survived postoperatively. The medial plantar flap encountered the venous crisis in postoperative 3 days, and regained the normal blood supply after continuous bleeding for 2 days. All patients were satisfied with cosmetic and functional outcome in average 10- month follow-up. The appearance and sensory function of donor toe repaired by medial tarsal flaps was best among three ones. Conclusion Depending on the Y-V vascular pedicle lengthening technique, the local pedical flaps of foots are enlarged scope for coverage of great toe after wrap-around flap harvest, which can decrease the complication of donor site at the most.
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@#Objective To report the anatomical study and clinical application of the vascularized composite fibula perforating osteoseptocutaneous flap. Methods Latex injection studies were performed on 24 adult cadaveric lower limbs. The presence, prevalence, and location of the peronel artery and its perforators in the distal leg were documented. 16 vascularized fibul osteoseptocutaneous flaps were performed for reconstruction of composite soft-tissue defect of limbs. The flap areas ranged from 6 cm×4 cm to 16 cm× 8 cm. Results A mean of 5.3 perforating vessels of the peroneal artery was noted in the specimen. 40.6% of them were muscularcutanous perforators, and the other were septacutanous perforators. The perforating vessels were all located within 3.1 cm from the postlateral fibula. The average diameter was 1.1 mm at the deep fascial level, and the interval of them was 4-8 cm. There were two constant perforators which located about 15-25 cm and 4-7 cm from the lateral maleolar respectively. All of the 16 clinical cases survived uneventfully and the time to union of the graft-host junction site were 3 to 5 months. The appearance of flaps and the function of the limbs were satisfied during 10 to 36 months following up. Conclusion It is the anatomic basis that there are pedorating vessels of the peroneal constantly. The vnscularized compound fibula perforating osteoseptocutaneous flap has the advantage of flexible design. It is the safe and suitable choice in the cases when compound bone and soft tissue defects of the limbs are required for reconstruction.
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@#Objective To identify the practical microsurgical procedure for repairing in site of skin avulsion injury in hand, and evaluate the long-term following-up results. Methods From January 2001 to May 2005, 21 cases of skin avulsion injury in hand were treated in our department. The surgical procedures thumb skin was revascularized with vein graft from forearm, and the other part of injuried hand was resuffaced by the thickness skin graft taken from the original degloved skin, which was suitable for degloving injury in-graft, the dorsum and palm of hand was skin grafted by the original skin thinned, which was suitable for complete degloved injury at the proximal interphalangeal level. Results All the repaired skin were survival in 16 patients, partial necrosis occurred in 4 cases, which was severely crushed, required debridement and skin graft on the residual defect. Whole failure in 1 case, which underwent secondary amputation. Follow-up at 10-28 months shows acceptable cosmetic and sensible results, slight scarring was present on the volar as-pects of hand. The range of motion of the thumb and fingers was almost complete. All patients regained new jobs. Conclusion Individualization of mierosurgical methods for repairing in site of skin avulsion injury in hand does represent the best solution.
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Objective To discuss the donor site complications and the treatments of the anterolateral thiIgh flap transfer. Methods From July 1988 to July 2007,427 patients treated by anterolateral thish flap surgery were followed up.The donor sites were treated by several methods,including direct closure(49 cases),skin graft transfer(258 cases),anterolateral fascial flap transfer(27 cases),musculocutaneous flap and skin sraft transfer(65 cases), superficial epigastric artery flap transfer(28cases).The area of these flaps ranged from 30 cm×10 cm to 18 cm×7 cm.and the average follow-up was 21 months(ranged from 8 months to 54 months). All the data was analyzed by SPSS for Windows,Version 11.0.1. Results Short-term complications(within 4 weeks)and long-term complications (over 6months)were observed.The former included skin necrosis(5.4%),wound infection(4.0%),and necrosis of rectus femoris(0.5%); and the latter included chronic ulcer(4.9%), aerious scar(6.6%), serious discomfortable(5.9%),and quadriceps femoris disfunction(3.7%).The statistical results showed that there was a close correlation between the donor site morbidity and the surgical methods. Conclusion The complications of the donor site cannot be ignored.Protect the soft-tissue of the donor site carefully,design all appropriate operation plan.Careful preoperative examination and local flap transplantation can effectively decrease the rate of complications.
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Objective To investigate the effects of swan shaped memory connector(SMC) on the bone mineral density and mechanical properties of humeral fracture in rabbits in order to disclose the mechanism of SMC stimulating fracture healing. Methods Shafts of both humeri of 40 rabbits were osteotomized. One side was selected to fix with SMC, but the contralateral side was fixed with the 4 hole dynamic compression plate (DCP). Eight rabbits were sacrificed and the humeri were harvested respectively at 2, 4, 8, 12 and 16 weeks after operation. The bone mineral density(BMD) was examined by dual energy radiographic absorptiometry(DRA). The mechanical properties were assessed by mechanical traction test. Results From 4 to 16 weeks after operation, the BMD in SMC group was significantly higher than that in DCP group ( P
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Objective To investigate the characteristics and the effect of severed hallux replantation.Methods Eighteen completely severed halluces had been replanted since 1991.Injuried foot were kept in extending at 90?-120? position.The sequence of hallux replantation was opposed to the classical order and was so called"the retrograde replantating means(RRM)".The order of RRM was defined as follows: skin of toe abdomen→subcutaneous vein of toe abdomen→inhered toe nerve→inhered toe artery→flexor toe tendon→toe fixation by a single K-needle→extendor toe tendon→artery in the back of toe→subcutaneous vein of toe back→skin of bilateral and back.Results Sixteen of eighteen halluces survived replantation(89.9%).The total flexion degree in replanted halluces was 25?～70?.The appearance of amputated toes restored well.The two-point discrimination was 10～16 mm.Eleven cases walked as entirely usually in gait, and seven cases had basic normal gait.Conclusions Replantation of severed halluces could alleviate wound and remnant greatly.The recovery of foot function and aspect of replanted toes was satisfactory.The RRM gradation showed a distinctive advantage that there was no requiring for injuried foot be moved during operation.
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Objective To explore the effects of swan-like memory compressive connector(SMC) made of Ni-Ti shape memory alloy on stress shielding rate, struct ure and mechanical properties as well as the blood flow of cortical bone of expe rimental fracture healing. Methods Mid-shaft osteotomies of bilateral humerus we re performed in 56 rabbits. One side was randomly fixed with SMC, and the other side was plated with a 4-holes dynamic compressive plate (DCP). At 2, 4, 8, 12, 16,and 20 weeks after operations, the humeri in 8 rabbits were harvested. The st ress-shielding rate was measured using axial compressive test in situ samples. T he geometrical structure and bone density were examined by CT scans, and the mec hanical property was assessed by torsion tests. Blood flow was measured in real time using Laser-Doppler flowmetry. The cortical bone perfusion of 16 rabbits wa s measured at 10 time intervals (after periosteotomy, after fracture, instant af ter fixation, at 1, 3, and 7 days, and 2, 4, 8, and 12 weeks postoperatively). B lood flow was measured at outer and inner cortical bone beneath the fixation. Si multaneously, anteroposterior radiograph of the humerus was taken. Results The s tress-shielding rate in SMC group was significantly lower than that of DCP group (P