BACKGROUND:Periprosthetic fracture of the femoral of the knee after total knee arthroplasty is one of the common complications,and there is a lack of biomechanical research on the periprosthetic fractures of the femoral of the knee under different bone strength conditions.The three-dimensional finite element analysis can provide a biomechanical basis for clinical practice. OBJECTIVE:To investigate the biomechanical changes of anterior femoral notching after total knee arthroplasty under different bone strengths,and to provide a mechanical basis for the clinical prevention of supracondylar femoral periprosthetic fractures after knee arthroplasty. METHODS:The femoral CT data of healthy adults were obtained,and the three-dimensional model of femoral lateral replacement of the knee joint was established by Mimics,Geomagic studio,and Solidworks software.Anterior femoral notching models of different depths were constructed,and the models were imported into ANSYS software to analyze the changes of biological stress on the femoral condyle with different bone strengths and different anterior femoral notching depths.The stress changes of the femoral anterior condyle section after and before the filling of anterior femoral notching with bone cement were analyzed. RESULTS AND CONCLUSION:(1)Under any bone strength,the supracondylar stress increased with the depth of anterior femoral notching.In normal bone conditions,there was a stress abrupt change point when the anterior femoral notching depth was between 3 mm and 4 mm.In the case of osteoporosis,there was a stress abrupt point when the anterior femoral notching depth was between 2 mm and 3 mm.(2)When anterior femoral notching occurred during knee arthroplasty and the depth exceeded the thickness of the bone cortex,the supracondylar stress of the femoral gradually increased as the bone strength decreased.(3)The stress of the anterior femoral condyle section decreased when the model with an anterior femoral notching depth of 3 mm was filled with bone cement.(4)The results show that anterior femoral notching should be avoided during knee arthroplasty,especially in patients with osteoporosis.If anterior femoral notching occurs during surgery,bone cement can be used to evenly fill the anterior femoral notching to reduce the supracondylar stress of the femur and reduce the incidence of periprosthetic fractures of the femoral joint

Objective To explore the influence factors of hidden blood loss during the treatment of femoral intertrochanteric fractures with percutaneous compression plate( PCCP) in elder patient. Methods The data of 136 patients with intertrochanteric fracture in our hos-pital from March 2009 to March 2012 treated with percutaneous compression plate were retrospectively analyzed,the effect of age,fracture type,preoperative aspirin,internal diseases on perioperative hidden blood loss, and different haemoglobin ( HGB) levels in patients with dif-ferent distribution were analyzed. Results The mean hidden blood loss volume was 499 mL,which accounted for 92. 54% of the total blood loss. The mean HGB decline was 11 g/L. The rate of on admisson haemoglobin level lower than 80 g/L was 6. 62% in AO type A2. 3 and A3 groups,and the rate of postoperative haemoglobin level lower than 80 g/L was 14. 70%. The average hidden blood loss for AO type A2. 3 (862 mL) and A3 (698 mL) were higher than those for AO types A1 (430 mL),A2. 1 (450 mL) and A2. 2 (415 mL) (P<0. 05). Multi-variate linear regression analysis showed that comminuted fracture and preoperative aspirin treatment were independently associated with in-creased perioperative hidden blood loss. Conclusion It indicated that the overt blood loss was fewer for PCCP operation. Intertrochanteric fracture was the main reason for substantial perioperative hidden blood loss. Types A2. 3 and A3 intertrochanteric fracture were early predic-tive factors of postoperative haemoglobin level lower than 80 g/L in elderly patients.

Objective To investigate the safety of hip arthroplasty during the perioperative period in aged patients with femoral neck fracture .Methods The clinical data in 56 elderly cases of femoral neck fracture treated by hip arthroplasty ,aged more than 65 years old ,were performed the retrospective analysis .Results Among 56 cases ,54 cases hospitalized for 21d[(18-31)d] and suc-cessfully were discharged ,the Harris scores were increased from preoperative 30 (0 -38) to postoperative 83 (72 -91) ,the func-tion of hip joint was obviously improved ;2 cases with the preoperative poor tolerance score died during perioperative period ,there were 3 cases(5 .4% ) of postoperative hip hematoma ,1 cases(1 .79% ) of postoperative hematoma developed secondary bacterial in-fection after puncture and 3 cases (5 .4% ) of postoperative posterior dislocation in the early stage and no case of deep venous thrombosis (DVT) accompanying clinical symptoms .Conclusion Hip arthroplasty is a effective measure for treating aged patients with femoral neck fracture .But those patients with poor operative tolerance should select this operation cautiously

Objective To evaluate the clinical results of proximal humeral internal locking sys-tem(PHILOS)self-locking plates in treatment of proximal humeral fractures. Methods There were 35 patients including 19 males and 16 females(at mean age of 53.5 years,ranging from 29 to 92 years)with proximal humeral fractures treated with PHILOS plate.According to the Neer's classification sys-tem,there were two-part fractures in 19 patients,three-part fractures in 15 and four-part fractures in 1.Surgery was performed with PHILOS serf-locking plate via dehopectoral approach.All patients were fol-lowed up for mean 18.9 months(6-46 months)and evaluated by using Constant score and X-rays. Re-suits X-rays proved that all fractures got good reduction and complete healing during 8-12 weeks.The latest Constant scores was mean 89.5 points(82-94 points).There were no complications including plate loosing.humenral head necrosis or gleno-humeral ioint osteoarthritis. Conclusion PHILOS plate is a good choice for treatment of proximal humeral fractures because of its advantages including easy operation,stable fixation,good clinical results and few complications.

Objective To discuss how to reduce the incidence of postoperative infection and am-putation of patients after earthquake.Methods The wound infection and corresponding therapeutic outcome were analyzed in 592 patients in front line hospitals and station hospitals.Results The inci-dence of infection was 30. 7% in patients treated in front hospital within 8 hours post-trauma but 79. 9% after 8 hours post-trauma. There included 1 patient(0. 2%) with amputation due to clostridial myonecro-sis and 5(1. 2%)with amputation due to serious infection. Incidelice of postoperative wound infection was 7. 1% after selective operation for close injury. The incidence of infection in patients in station hospi-tals was 50. 8%, with no amputation, because they received debridement and antibiotics in site or front line hospitals. No postoperative infection was found in patients with close injury treated with selective op-eration in station hospitals. The major bacteria of wound infection in either front line hospitals or station hospitals were enterococcus faecalis and Eschrichia Coli. Incidence of combined infection was higher than that of single infection. And Gram-Negative bacillus infection exceeded Gram-Positive bacillus infection. The major wound infection obrained effective control through treatment with sensitive antibiotics.Con-clusions After earthqiale, the incidence of infection in patients with open injury is high, with high am-putation rate due to serious infection. Therefore, we propose performing as soon as possible debridement and external fixation with antibiotic treatment but reducing internal fixation. The postoperative infection late of patients with close injury in front line hospitals is much higher than that in station hospitals;their-fore, patients with stable vital signs should be transported to station hospitals as early as possible in order to reduce incidenee of infection.

Objective To discuss the application value and improvement of principle of multi-echelon medical care in emergent rescue of the injured in Chinese Wenchuau earthquake. Methods The author analyzed and evaluated the medical rescue that was done at disaster site, in the front line hospital and higher level hospitals during earthquake. Results A total of 4 689 patients were treated at disaster site, including 413 patients with severe injury, of whom 3 died. Different kinds of operations including debridement were performed at disaster site, with infection incidence of open wound was nearly 80%. In the front hne hospital, 1 400 patients were treated, with 200 operations done. Of all, 110 patients with severe trauma were treated emergenfly, with an amputation rate of 3.0% and postoperative infection incidence of 66.8%. In the station hospitals, 125 patients received definite surgeries, with 1-5 surgeries per injury site. There was no postoperative cross infection, amputation or death. Conclusions The multi-echelon medical care is the basic mode for medical rescue of large number of patients in natural disaster rescue. First aid at disaster site should be performed as early as possible. Transportation is crucial for successful rescue and an improved patient grading system can help increase the efficiency of rescue. The front line hospitals should mainly provide life support, debridement and fixation of simple fracture, while the specific treatment and definite surgery should be carried out in the station hospitals.

BACKGROUND: As reported in some literatures, articular dysfunction following limb lengthening is one of the commonest complications, but some scholars believe that the articular dysfunction after lower limb lengthening is avoidable providing appropriate technical operation and effective function prevention.OBJECTIVE: To investigate the changes of articular function of knee during limb lengthening in rabbits so as to provide a experimental basis for clinical tasks.DESIGN: A randomized controlled trial SETTING: Department of Orthopeadics, Affiliated Hospital of Some Military Medical University.PARTICIPANTS: Study was conducted in the Experimental Animal Center of the Third Military Medical University of Chinese PLA from February 2001 to June 2002. Totally 30 healthy adult New Zealand rabbits obtained from the Experimental Animal Center of the Third Military Medical University of Chinese PLA were randomly divided into lengthening group and delayed observation group(observed at 3 months after the stop of lengthening).METHODS: Every group was further divided into three sub-groups according to distraction range: 10%, 20% and 40%. Upper-tibia metaphysis distraction was adopted at the rate of 1 mm per day . Distraction and iconography changes of knee joint were observed with X-ray. The motive range of knee was investigated at the end of distraction and three months later.MAIN OUTCOME MEASURES: Articular motive range of the knee before the distraction, at the end of distraction and three months later, X-ray resutls RESULTS: ① There was no obvious radiographic change in knee at every time point in each group. ② Significant flexion disorder in knee was found in 20% distraction subgroup( P ＜ 0. 05), which was only 44. 7% of normal motive range in 40% distraction subgroup( P ＜ 0. 01) . Motive functions of knee in delayed observation group were significantly improved; thereinto,20% distraction subgroup returned to preoperative level, while 40% distraction subgroup also had significant improvement compared with that of 3 months earlier but still lower than normal level, which was only about 88.5% of normal level( P ＜ 0.05).CONCLUSION: Temporary articular dysfunction might occur during limb lengthening process, and mostly during big range of distraction. Although the dysfunction could be gradually recovered after the stop of lengthening, active prevention is still necessary.

Aim To evaluate the clinical value of two cervical spinallocking plates, Orion and Zephir, and a new anterior cervical instrumentalsystem combining an intradiscal cage with an integrated plate(PCB) afteranterior cervical decompression surgery. Methods 47 patients were followedup for 7 - 26 months with an average of 15 months after surgery. Of them, 30were treated with Orion, 1 1 with Zephir and another 6 with PCB. Results 26cases with preoperative intervertebral space constriction and 18 cases withchanges of cervical physiological protrusion all achieved satisfying effect ofrebuilding intervertebral space height after operation. The cases with obviousintervertebral space height loss were not seen after follow up. The physio-logical curvature corrected by operation was well kept. Neurological functionwas improved in 43 cases on different extent after operation. The other 4cases with no obvious recovery of neurological function were all that withcomplete paraplegia after trauma. Conclusion PCB is suitable for treatmentof the acute cervical protrusion or the cervical spondylotic myelopathy at onelevel. Zephir and Orion are suitable to all kinds of cervical vertebra lesions atmore than one level and complex lesion at one level, which helps the re-covery of cervical physiological curvature and height of disc space.

Objective To construct the tissue-engineered bone with the allogenic demineralized bone matrix (DBM) as the scaffold material and the in vitro cultured human mesenchymal stem cells (hMSCs) and to evaluate the geosteogenesis efficacy and safety by implantation of tissue-engineered bone in nude mice subcutaneously. Methods After cultured and amplified, hMSCs were combined with DBM at the density of 1.857?10 6/ml to construct the tissue-engineered bone. The hMSCs and DBM combination was cultured in vitro for 3, 5, 7 d and tested for biocompatibility under scanning electron microscope and each sample was implanted into 36 nude mice subcutaneously, DBM as the control. The culture suspension of the hMSCs and DBM combination was injected into another 4 nude mice to observe the oncogenesis. Specimens were harvested after 4, 8, 12 weeks for histological observation. Results At day 3 of culture, hMSCs and DBM combined well and at day 5, the cell matrix was productive and full of the scaffold. The osteocytes were found inside in the scaffold in the experimental groups, while no osteocytes in the control groups. Conclusion The DBM has good biocompatibility, providing good three-dimension space for hMSCs. It is safe and successful to construct the tissue-engineered bone by the method we introduced.

Objective To investigate the adaptation of metabolism of the arthrodial cartilage for limb lengthening. Methods Thirty New Zealand rabbits were divided into two groups: limb lengthening group (A) and delayed observation group (B). Each group was further divided into three sub groups ( n =10) according to the distraction ranges: 10%, 20%, and 40%. Upper tibia metaphysis lengthening was adopted at 1 mm/d rate of distraction and iconography changes of the knee joint were observed with X ray. The contents of glycosaminoglycan (GAG), hydroxylysine (HYL), and hydroxyproline (HYP) were determined by biochemical techniques. Results ① There was no obvious imaging change of knee articular cartilage at every time point in each group. ② The content of GAG was normal in group A 10 , and B 10 , and B 20 , but the content of galactosamine decreased obviously in group A 20 ( P 0.05). The content of GAG recovered obviously in group B 40 as compared with that in group A 40 . ③ The ratio of HYL to HYP was 0.18 and 0.17, respectively in group A 40 and group B 40 , but it was normal in other groups, nearly 0.24. Conclusion Metabolism of the arthrodial cartilage during low distraction range can adapt the stimulation of distraction, but great distraction range may result in transitory disorder in metabolic function of the arthrodial cartilage.