Debridement， Antibiotics and Implant Retention for the Treatment of Periprosthetic Joint Infection After Arthroplasty： A Narrative Review / 中山大学学报(医学科学版)

Periprosthetic joint infection （PJI） following joint arthroplasty is devastating and technique-demanding. At present， the surgical treatment for PJI includes debridement， antibiotics， and implant retention （DAIR）， single- or two-stage revision， arthrodesis， and amputation. DAIR is appealing to both surgeons and patients as it can avoid unnecessary implants removal， making it less time-consuming and less invasive. In this article， we review the current knowledge in surgical timing， intraoperative details and antibiotics strategy of DAIR.

Risk factors for myocardial infarction following primary total joint arthroplasty / 中国组织工程研究

BACKGROUND: Myocardial infarction is one of the catastrophic complications after total joint arthroplasty. However, the risk factors and predictive model have not been reported in previous research after total joint arthroplasty. OBJECTIVE: To study the incidence and risk factors of myocardial infarction after total joint arthroplasty, and develop a nomogram for predicting the myocardial infarction after total joint arthroplasty. METHODS: We retrospectively reviewed the data of 5 746 patients who underwent total hip arthroplasty or total knee arthroplasty in the Affiliated Hospital of Qingdao university and the People’s Hospital of Xixiu District between September 2013 and July 2017. The baseline characteristic, preoperative comorbidities, preoperative examinations, operative data, other hospital information and follow-up data were collected, recorded and were used to analyze the risk factors of myocardial infarction. In addition, a nomogram was developed based on the independent risk factors for predicting the myocardial infarction after total joint arthroplasty, and receiver operating characteristic curve and calibration curve were used to evaluate the nomogram. RESULTS AND CONCLUSION: Forty-eight patients affected myocardial infarction within 14 days after total joint arthroplasty, and the incidence of myocardial infarction was 0.8%. Multivariate Logistic analysis indicated that age-adjusted Charlson Comorbidity Index, anesthesia type and atrial fibrillation were independent risk factors for postoperative myocardial infarction (P < 0.05). The risk of myocardial infarction in patients with age-adjusted Charlson Comorbidity Index ≥ 5 was higher than patients with age-adjusted Charlson Comorbidity Index < 5. The risk of myocardial infarction in patients receiving general anesthesia was higher than that of patients receiving epidural/lumber anesthesia. The risk of myocardial infarction in patients combined with atrial fibrillation was higher than that in patients without it. Receiver operating characteristic curve showed that the nomogram has a high degree of discrimination (AUC=0.730, 95%CI: 0.661-0.799), and the calibration curve showed that the model had a high degree of calibration. A predictive model based on age-adjusted Charlson Comorbidity Index, anesthesia type and atrial fibrillation can accurately predict the myocardial infarction following total joint arthroplasty.

A mid-term clinical follow-up of unicompartmental knee arthroplasty with fixed bearing / 中国组织工程研究

BACKGROUND: Most of the domestic and foreign literatures reported the mid-term and long-term effects of the unicompartmental knee arthroplasty of the mobile bearing, but few reported the mid-term and long-term clinical effects of the unicompartmental knee arthroplasty of the fixed bearing. Simultaneously, most of the studies did not analyze the knee function recovery and the lower limb force line change at different time points after the fixed bearing unicompartmental knee arthroplasty, and also ignored the follow-up of the patients’ self-feeling after the unicompartmental knee arthroplasty. OBJECTIVE: To explore the mid-term clinical effect of fixed bearing unicompartmental knee arthroplasty in the treatment of medial compartment osteoarthritis of knee joint and to observe the change of force line of lower limbs. METHODS: From January 2014 to January 2015, a retrospective analysis was made of the data of 66 patients diagnosed as osteoarthritis of the medial compartment of the knee in the Department of Arthritis, Foshan Hospital of Traditional Chinese Medicine. According to the inclusion and exclusion criteria, 66 patients were included, including 18 males and 48 females, aged (62.36±16.33) years. The American Knee Society knee score and the hospital for special surgery knee score were used to assess the knee function before and 1, 3 and 5 years after the operation. Visual analogue scale score was utilized to evaluate the severity of knee. Forgotten joint score was used to assess the subjective feeling of prosthesis after unicompartmental knee arthroplasty. Hip-knee-ankle angle and tibiofemoral angle were measured using X-ray films before treatment and at follow-up to evaluate the force line of weight-bearing lower limbs. RESULTS AND CONCLUSION: (1) The postoperative follow-up time was 5-6 years, averagely 5.5 years. The incision healed in the first stage. There was no early complication such as joint infection or lower extremity deep vein thrombosis, and there was no prosthesis loosening, dislocation or other diseases of the contralateral compartment and patellofemoral joint. (2) The American Knee Society knee score clinical score, American Knee Society knee score function score, hospital for special surgery knee score, knee motion range and visual analogue scale score were lower at 1, 3 and 5 years after operation than those before treatment (P 0.05). (3) Forgotten joint score was higher at 3 and 5 years after treatment than that at 1 year after treatment (P 0.05). (4) Hip-knee-ankle angle and tibiofemoral angle were significantly improved after treatment in all patients compared with those before treatment (P 0.05). (5) The results show that the mid-term clinical effect of unicompartmental knee arthroplasty with fixed bearing is satisfactory, and the degree of self-prosthesis is high. After treatment, the force line of lower limbs was improved, and there was no significant change in the 5-year follow-up.

Clinical pathways in total hip or knee arthroplasty as compared with traditional pathways: A meta-analysis / 中国组织工程研究

BACKGROUND: Hip and knee arthroplasty has been widely carried out in various levels of hospitals. The amount of hip and knee joint surgery has increased year by year. The surgical methods and techniques have reached a difficult time. Promoting the clinical pathway is an effective method to improve the treatment effect. OBJECTIVE: To systemically evaluate the difference between the clinical pathways and conventional pathways in total hip arthroplasty and total knee arthroplasty. METHODS: Clinical trials about the comparison of conventional and clinical pathways in total hip arthroplasty and total knee arthroplasty were searched in MEDLINE, Cochrane Library, EMbase, and CNKI. Study selection, data collection and evaluation of methodological quality were undertaken by two reviewers independently. The Cochrane Collaboration’s RevMan 5.0 was used for data analyses. RESULTS AND CONCLUSION: (1) Totally 17 clinical trials meeting research design criteria were included in this analysis, including 13 semi-randomized controlled trials and 4 randomized controlled trials. (2) The incidence of complications in the traditional method group was higher than that in the clinical pathway group [OR=0.63, 95%C/(0.53, 0.74), P < 0.000 01]. (3) Pain visual analogue scale score [MD=1.49, 95%C/(0.69, 2.85), P=0.001], postoperative Harris hip score [MD=19.31, 95%C/(-13.98, -4.92), P< 0.000 1], and 5-year prosthesis survival rate [OR=0.59, 95% Cl (0.36, 0.98), P=0.04] were better in the clinical pathway group than in the traditional method group. (4) There was no significant difference in postoperative mean deviation of mechanical axes of lower limbs after total knee arthroplasty in both groups [MD-0.0Q, 95%C/(-0.14, 0.14), P=0.99]. (5) Results showed that compared with traditional technique, hip and knee arthroplasty patients who entered the clinical pathway had better clinical efficacy, fewer complications and better joint function after operation.

Application and progress of three-dimensional printing technology in hip arthroplasty / 中国组织工程研究

BACKGROUND: Three-dimensional (3D) printing technology is a new rapid prototyping technology, which has been initially applied in orthopedics, especially in the clinical application of hip replacement surgery. OBJECTIVE: To summarize the application status, existing problems and future development direction of 3D printing technology in hip arthroplasty. METHODS: The relevant articles published between January 2000 and March 2019 were retrieved from PubMed, CNKI and WanFang databases. The keywords were "3D printing, rapid prototyping, additive manufacturing, computer aided, computer-assisted, hip, hip replacement, hip arthroplasty, revision hip arthroplasty" in English and Chinese, respectively. Initially, 1 833 articles were retrieved, and finally 105 eligible articles were included for result analysis in accordance with the inclusion and exclusion criteria. RESULTS AND CONCLUSION: (1) In the clinical application of hip replacement surgery, 3D printing technology Is mainly used to make anatomical models for clinical teaching or preoperative plan, patient-specific surgical guides, customized implants or prostheses. (2) The advantages of 3D printing technology can make up for the deficiency of traditional treatment, and it can help to optimize the surgical plan, shorten the operation time, decrease the bleeding, reduce postoperative complications, improve the accuracy of surgery and clinical results. (3) Individualized treatment with 3D printing technology will become a new direction in hip arthroplasty.

Application status of 3D printed polyetheretherketone and its composite in bone defect repair / 中国组织工程研究

BACKGROUND: Polyetheretherketone (PEEK) and Its composites have a unique set of properties, and 3D printing technology can customize personalized Implants according to the patient's condition, and the effective combination of the two plays a significant role In the field of bone repair. OBJECTIVE: To summarize the application status of PEEK and Its composite combined with 3D printing technology In the field of bone repair, and to further predict the application prospects of the effective combination of the two. METHODS: CNKI, PubMed, and Web of Science databases were retrieved with the search terms “PEEK, PEEK composites, bone defect repair, PEEK Implants, PEEK 3D printing, prosthodontlcs” in English and Chinese, respectively, for the articles published from April 1995 to April 2019. Totally 147 articles were searched, and finally 51 eligible articles were enrolled for review in accordance with the inclusion and exclusion criteria. RESULTS AND CONCLUSION: Biologically active materials and the particles or fibers with Improved mechanical properties were Introduced Into the PEEK matrix to prepare its composite. 3D printing technology was used to precisely customize Implants that are highly matched to the patient's defect. The Implants with good biocompatibility, bioactlvity, and mechanical properties exhibited good therapeutic effects In the repair of skull, jaw, spine, lumbar vertebra, artificial joint and oral defects. They Improved patient satisfaction after treatment. This article summarized the application of PEEK, its composite and 3D printing technology In the repair of various bone defects, and expressed its views on the application and prospect of personalized PEEK implants or prostheses prepared with 3D printing technology.

Clinical significance of external wall of femoral intertrochanteric fracture and the treatment of internal fixation / 中国组织工程研究

BACKGROUND: The concept of the lateral wall as a hot area has emerged in recent years, and has great guiding significance for the treatment of intertrochanteric fractures. OBJECTIVE: To review the definition, scope, thickness of the lateral wall and its important role in the surgical treatment of intertrochanteric fractures. METHODS: The authors searched Wanfang, CNKI, PubMed, and Web of Science. The search terms were “intertrochanteric fracture, lateral wall, fracture fixation” in Chinese and English. The retrieved documents were sorted, analyzed and summarized. RESULTS AND CONCLUSION: (1) The definition, scope, thickness and measurement method of the lateral wall and its clinical significance were sorted out. (2) Classification criteria based on lateral intertrochanteric fractures of the femur were summarized. (3) In terms of treatment, four kinds of treatment methods: Extramedullary fixation, intramedullary fixation, artificial joint replacement and other treatment methods were listed. Causes and treatment of fracture of lateral wall during and after operation were analyzed. (4) The results showed that the integrity of the lateral wall directly affected the stability of the internal fixation, even the success of the internal fixation. The complete lateral wall can prevent the distal femur from moving inward and the head pin from withdrawing, and prevent the coxa varus deformity. Clinicians should make use of detailed imaging examination, analyze fracture types, comprehensively consider various factors, and select appropriate repair methods.

Hardware System for the Test of Artificial Joint Biomechanics / 中国医疗器械杂志

In the research of artificial joint biomechanics, it is a common method in the world to evaluate the biomechanical properties of the implanted fixtures through experiments . The domestic research started late, and the corresponding testing methods were lacking. There is still no unified standard. In this paper, a complete hardware test system was designed and built around the existing mechanical testing machine, including:binocular vision catcher, torque bearing clamp, film pressure sensor and so on. The system can accurately measure the relative motion angle value, external torque value, and inter pressure value of each joint. It has some reference significance for the forming and standardization of the artificial joints' evaluation system.

Development of Software System for Artificial Joint Biomechanics / 中国医疗器械杂志

In the research of artificial joint biomechanics, it is a common method in the world to evaluate the biomechanical properties of the implanted fixtures through experiments . The domestic research started late, and the corresponding testing software were lacking. There is still no special software. In this paper, an integrated software test system was designed and built based on the existing hardware system, including:hardware control, data collection, data save, data processing and display. It can directly show the 3D motion trajectory and the angle curve of joints. The system can accurately measure the relative motion angle value, external torque value, and inter pressure value of each joint. It has some reference significance for the development of the artificial joints' evaluation system.

A study on the clinical effects of auxiliary exercise instrument combined with systematic activity for preventing postoperative DVT of artificial joint replacement / 中国医学装备

Objective: To observe the clinical effects of the combination of auxiliary exercise instrument and systematic activity for preventing the formation of postoperative deep venous thrombosis (DVT) of artificial joint replacement. Methods: 217 patients who once underwent replacements of hip joint and knee joint were randomly divided into 3 groups as random method. The patients of A group (72 cases) received auxiliary exercise instrument, and those of B group (73 cases) received systematic activity, and those of C group(72 cases) received combinative treatment of auxiliary exercise instrument and systematic activity. And all of these patients received corresponding nursing scheme to prevent postoperative DVT of artificial joint replacement, respectively. And the symptoms of them at pre-operation and 12d of post-operation were observed, respectively, and the changes of plasma D- dimer(D-D), prothrombin time activity percentage (PTA), fibrinogen (FB), activated partial thromboplastin time (APTT), prothrombin time (PT) and international normalized ratio (INR) also were detected and compared. Results: At the postoperative 1st d, 3th d, 7th d, 12th d, the limb diameter above ankle at 5 cm of patients of C group was significantly less than that of other two group (F=4.066, F=4.256, F=3.452, F=4.678, P<0.05), respectively. However the differences of limb diameter above patella at 10cm of patients among three groups were no significant. And surface temperature above ankle at 5 cm of the C group at 1st d, 3th d, 7th d and 12d were significantly lower than those of other two groups (F=4.659, F=4.325, F=3.196, F=4.754, P<0.05), respectively. And the numbers of gastrocnemius Neuhof symptom and gastrocnemius Homans symptom of C group were significantly lower than that of other two groups (x2=13.317, x2=8.517, P<0.05), respectively. At the 7th d, the plasma D-D of C group was significantly lower than other two groups (F=5.063, P<0.05), while the differences of other plasma indicators among the three groups were no significant. Conclusions: Auxiliary exercise instrument combined with systematic activity has better therapeutic effect for preventing postoperative DVT of artificial joint replacement and it is worthy to be popularized in clinical practice.

Hot issues related to modern hip prosthetic materials / 医学研究生学报

Artificial prosthetic material is one of the important factors determining the effect of artificial hip replacement.There are mainly three types of interfaces in the prosthetic materials: the fixed in-terface,the friction interface,and the interface between the modular prostheses.Porous metals improve the osseointegration of the bio-logical fixed interface.High crosslinking polyethylene and composite ceramics significantly reduce the wear of the friction interface.The modular prostheses of ceramic ball head can reduce the wear particles and corrosion.However,the prosthesis loosening,wear and metal corrosion are still the most important factors affecting the medium-long term effects of artificial hip replacement.This article reviews the research progress of artificial hip prosthesis materials from the perspective of the three prosthetic interfaces.

Effect of surface modification on biotribological properties of ultra-high molecular weight polyethylene artificial joints / 中国骨伤

Friction and wear of ultra-high molecular weight polyethylene is a major cause of artificial joint failure. According to mechanism of surface modification method, friction reduction and wear-resistance properties of UHMWPE were improve by several kinds of surface modification methods. Meanwhile, this do not damage the internal structure and properties of UHMWPE. In the process, condition is easy to control and operation is simple. However, reaction time of radiation crosslinking method is too long, the material will be oxidized embrittlement; Monomer itself homopolymerization are seriously in the process of surface grafting; The injection layer of ion implantation methods is very thin and easy to be destroyed. Objective in order to provide a reference for further research on the biotribological properties of ultra-high molecular weight polyethylene artificial joints. At present, as the researches of UHMWPE material main focus on abrasion resistance, and application in the clinical trial is the focus of research, it has a wide prospect in the future.

Advances in effect of total hip arthroplasty on sexual life of patients / 第二军医大学学报

Patients with hip osteoarthritis or other hip joint diseases suffer from pain, limited joint function and psychological disorder, which are responsible for difficulties in sexual life. Total hip arthroplasty can effectively relieve the pain of hip joint and improve the range of joint motion, thus improving the frequency and performance of sexual life of patients. Good quality of sexual life is related to the postoperative satisfaction of patients. However, patients can hardly get the correct guidance on this. After total hip arthroplasty, male patients are earlier to recover sexual life than female patients. The time of the most patients to recover sexual life is 1-3 months after surgery, and the safe position of sexual life is stand position. Sugerons should make positive and correct guidance for patients and their sexual partners about safe resumption of sexual life after total hip arthroplasty.

Impact of surface physical properties of artificial joint prosthesis materials on adhesion of Mycobacterium tuberculosis / 军事医学

Objective To study the effect of surface physical properties of different materials for the artificial joint pros -thesis interface on Mycobacterium tuberculosis adhesion .Methods The surface polishing coating , titanium coating and hydroxyapatite coating were chosen as the experimental materials to analyze the surface topography and measure the surface roughness, contact angle and surface energy .The M.tuberculosis strains were used by in vitro cultivation method and ob-served by scanning electron microscopy (SEM) to study the morphology of M.tuberculosis and the material surface adhe-sion.The influence of surface physical properties of the interface of the artificial joint prostheses on the proliferation and ad -hesion of bacteria was evaluatd .Results The titanium coating and hydroxyapatite coating materials were hydrophobic , while the surface polishing coating was hydrophilic .The contact angle and surface energy were significantly different ( P0.05)in the OD value of bacterial solution .The titanium coating had the largest amount of interface adhesion for M.tuberculosis, fol-lowed by the hydroxyapatite coating and the polishing coating .The difference between various materials was statistically sig-nificant (P<0.05).Conclusion The adhesion of M.tuberculosis in the surface of artificial joint prosthesis materials is closely related to the surface physical properties .A adhesiveness improves with surface roughness .

Regeneration and functional recovery of rabbit knee joint after osteotomy under control of external artificial joint / 医用生物力学

Objective To discuss the possibility for regeneration of knee joint with normal function under bionics biomechanical environment. Methods Seven normal rabbits with two metal frames respectively mounted on their femur and tibia of single (right) side leg by two threading pins of 1.5 mm diameter were used. Then the external artificial joints, containing two four-bar-linkage inside and outside of the knee to simulate motion trajectory of the joint in sagital plane were connected with the two preset fixed frames before osteotomy. The arthro-cartilage of the knee joint, crucial ligaments, semi-lunar fibro-cartilages, and partial under-cartilage-osseous intra articular capsule were cut off during osteotomy, with the patella, sesamoid bones remained intact. Insertion sites of muscle tendons were not invaded as far as possible, and capsules with ligaments outside were kept complete when the incision wound was closed by suture. The rabbits could move freely after osteotomy. The range of motion (ROM) of the knees in sagital plane and bony gap between the femur and tibia were measured by X-Ray films during the fracture healing after osteotomy. Results External artificial knee joints were successfully installed on right legs of 6 rabbits among the seven. The rabbits moved freely after osteotomy under the control of minimal invasive external artificial joint in bionics trajectory. The average angles between femoral shaft and tibial shaft at the 1st week after osteotomy were from (144.7±15.62)° in extremely flexed position to (44.2±25.77)° in extremely extended position, with ROM of (100.5±29.03)°. At the 12th week, the average angles were from (139.4 ± 12.92)° in extremely flexed position to (40.4±22.04)° in extremely extended position, with ROM of (99.0±23.39)°. No significant differences were displayed in flexed/extended position and ROM between the 1st and 12th week, with the bony gaps of the knees still existed but decreased significantly from (4.03±1.84) mm at the 1st week to (2.32±1.05) mm at the 12th week. In contrast, bony gaps of the opposite knees were not changed significantly, which were (1.27±0.22) mm on average. At the end of 16th week after osteotomy, the external artificial joints were removed. Newly born cartilage, with white color and smooth surface, were covered at lower end of the femur and upper end of the tibia. Typical trochlear surface appeared at the front side of regenerated cartilage corresponding to the posterior surface of the patella. And the regenerated fibro-bundle linkage similar with ligament, which started from bony structure of regenerated lower end of the femur and inserted into regenerated upper end of the tibia, was observed in each rabbit. At the 25th week, the average angles between femoral shaft and tibial shaft were from (148.3 ± 4.75)° in extremely flexed position to (48.30±17.57)° in extremely extended position, with ROM of (100.0±20.80)°. In the opposite (left) leg, the average angles between femoral shaft and tibial shaft were from (148.3±7.5)° in extremely flexed position to (21.6±9.09)° in extremely extended position, with ROM of (126.7±6.88)°, and the average bony gap of the knees after osteotomy was (1.4±0.59) mm, while that of the opposite (left) knees was (0.92±0.35) mm. Conclusions The external artificial joint with bionics trajectory could reserve the space for regeneration of rabbit knee joint by providing motion modeling environment, and proved the stress adaption during fracture healing. The present results indicated that regeneration of the knee joint after intra-capsular osteotomy in bionics biomechanical environment was possible.

Statistical analysis on artificial joint failure and its role in technology development / 医用生物力学

This paper expounds the statistical work on artificial joint failure and their primary results in China and abroad. From the view of clinical demand, biomechanics and engineering, the paper proposes that it is the basic technology, manufacturing techniques and clinical conditions that lead to artificial joint failure. The paper also elaborates the demand on further improving the clinical medicine of artificial joint and prosthesis technology, and presents some suggestions to promote the domestic statistics work on artificial joint failure.

Clinical effect of total hip replacement in 104 patients suffered from different diseases / 中国综合临床

Objective To evaluate the clinical effect and complications of total hip replacement (THR) in novel femoral neck fracture,old femoral neck fracture, aseptic necrosis of femoral head and coxa degenerative osteoarthropathy. To provide instructions to surgical indications and treatment effects analysis.Methods One hundrde and four patients were divided into 4 groups by disease type: novel femoral neck fracture group (n = 32 ), old femoral neck fracture group (n = 22) ,aseptic necrosis of femoral head group (n =34) and coxa degenerative osteoarthropathy group (n = 16). These patients were followed-up for 12 - 144 months after THR, their Harris standard score and complications data, before and after operation, were analyzed retrospectively. Results After operation, the Harris standard scores were 92. 6 ± 5.8,90. 1 ± 5. 2,86. 3 ± 4. 6,81.9 ±4. 1 in novel femoral neck fracture,old femoral neck fracture,aseptic necrosis of femoral head and coxa degenerative osteoarthropathy groups respectively, which were significantly higher than the scores before operation (25.6±1.8,36.7±2.6,52.9±4.3,42. 1 ±3.8,Ps ＜0.05). Conclusion THR has good effects in the four types of diseases. Short length of stay and high healing rate are marked characteristics of THR. More attention shoud be paid to the complications of THR.

Clinical multicentre retrospective study of treatment on radial head fractures / 中国综合临床

Objective To evaluate the treatment of radial head fracture of different type. Methods The clinical data of 80 radial head fracture cases from November, 1999 to December,2009 were collected and analyzed retrospectively. Among the 80 cases,12 cases received conservative treatment( all type Mason Ⅰ ) ;48 cases received open reduction internal fixation (ORIF) (4 case type Mason Ⅰ ,15 cases type Mason Ⅱ ,24 cases type Mason Ⅲ,5 cases type Mason Ⅳ ); 12 cases received removing radial head ( 4 cases type Mason Ⅲ and 8 cases type Ⅳ ).8 cases received artificial joint replacement ( 8 cases type Mason Ⅳ ). Results All cases were followed up for 1.0 -4. 1 years. According to the Mayo Elbow Performance Index, the excellent and good rate of treatment in nonoperative,ORIF,excision of the radial head as well as artificial joint replacement was 83.3 % (10/12) ,87.5 %(42/48) ,75.0% (9/12) and 100. 0% (8/8) ,respectively. Conclusions Conservative treatment can be selected for type Mason Ⅰ ;Open reduction and internal fixation can be selected for type Mason Ⅱ , type Mason Ⅲ and part of type Mason Ⅳ. The excision of radial head or mental prosthesis replacement is alternative for type Mason Ⅳ for those can not be treated with open reduction and internal fixation.

Nursing of subcutaneous hematoma of the chest wall after artificial femoral head replacement (a case report) / 中国实用护理杂志

Objective To discuss the subcutaneous hematoma of the chest wall after artificial femoral head replacement in order to improve the prognosis of patients. Methods One patient complicated with subcutaneous hematoma of the chest wall after artificial femoral head replacement on October,2009.Aborative treatment and nursing was given and the treatment effect was observed. Results The hematoma and congestion were all absorbed after two weeks of treatment and nursing. Conclusions The nursing point of subcutaneous hematoma of the chest wall after artificial femoral head replacement includes monitoring of vital signs, drainage volume, identification of anemia feature, scrupulosly systemic observation and nursing of hematoma.

Optimal design of ball socket on artificial cervical joint complexity by finite element analysis / 医用生物力学

Objective To optimize the design of ball socket of artificial cervical joint complexity. Method A three dimension model of the artificial cervical joint complexity was constructed by the finite element method. The height range of the ball socket handle in the model was set. A simulation was manipulated to optimize the height under the physical load. The stress and strain of the joint complexity with different sizes was analyzed and the systematic safety factor was also evaluated. Results The simulation showed that the maximum Von mises stress appeared at the joint of handle and bottom in the anteflexion position. As the height of the handle increased, the maximum strain increased, and the graph of minimum safety factor was Parabola curve. Conclusions Considering the systematic stability and mobility, when the height of handle is 6 mm, the design of ball socket is considered to be optimal.