Micro-finite Element Analysis of Bony Acetabulum with a Press-fit Acetabular Cup / 医用生物力学

Objective To investigate the trabecular stress distributions on the cortical bone and determine whether the cancellous bone can share the load of the acetabulum with a press-fit acetabular cup. Methods The acetabulum was scanned via micro-computed tomography (CT) to build a three-dimensional micro-finite element analysis (μFEA) model of the acetabulum. The trabecular stress and strain of the bony acetabulum were calculated following total hip arthroplasty (THA) to investigate the biomechanical characteristics of their distributions. Results With the implantation of the press-fit acetabular cup into the acetabulum, the high-stress zone of the articular surface was found to be located in the pubic bone area, with a maximum stress of 1.398 MPa. The largest high-stress zone within the articular surface was at the craniomedial part where it was supported by the iliac. For the cancellous bone within the acetabulum, the high stress was relatively widely distributed on the craniomedial part. When a 1.372 kN load was applied, the high stress was found at the craniomedial and anterior-inferior parts of the articular surface where it was supported by the iliac and pubic bone, with a trabecular micro-damage occurring in the anterior-inferior part. The highest tensile stress at the craniomedial part was 0.604 MPa. For the cancellous bone within the acetabulum, the high stress was mainly distributed on the craniomedial and anterior-inferior parts. Conclusions The high stress near the periphery of the articular surface showed a three-point circular distribution, which was mainly distributed on the iliac, ischial, and pubic bone area. The stress was distributed more uniformly owing to the deformation of the cancellous bone in the acetabulum. The cancellous bone in the acetabulum has the function of load-bearing.

Using customized acetabular cages for revision THA with severe bone defects / 中华骨科杂志

Objective To evaluate the results of computer-aid customized acetabular cages for patients with severe defects.Methods Twenty-three patients (8 males and 15 females) with a massive acetabular defects were involved in the present study from January 2005 to September 2014.The average age was 64.2 years (range,46-79 years).According to the American Academy of Orthopaedic Surgeons (AAOS) classification,20 had AAOS type Ⅲ defects and three had AAOS type Ⅳ defects.The customized cages were individualized to each patient's bone defects based on the rapid prototype three-dimensional printed models.The mean follow-up duration was 66.3 months (range,24-120 months).The clinical and radiographic outcomes of all patients were assessed at 6 and 12 weeks after surgery and at once yearly thereafter.Harris hip scores were assessed before surgery and at each follow-up.Postoperative radiographs were evaluated for cage position,migration,and graft incorporation.Complications and reoperations were assessed by chart review.Results The mean Harris hip score improved from 36.2±7.9 (range,20-49) to 81.8± 8.4 (range,60-96),and there is a significant difference between pre-and post-operation (t=23.23,P＜0.001).Individualized custom cages resulted in generally reliable restoration of the hip center.The difference of horizontal distance (between the center of each hip and pubic symphysis) between bilateral sides was-3.0±6.4 mm (range,-19-8 mm).The difference of vertical distance (between the center of each hip and the line connecting the inferior border of the bilateral tear drop) between bilateral sides was 0.4±2.8 mm (range,-4.5-5 mm).No re-revisions had been conducted.None of the cups showed radiographic migration,while one cage was suspected to be loose based on a circumferential 2-mm radiolucent line.Cancellous allografts appeared to be incorporated in 22 of 23 patients.One deep infection and one superficial infection were observed and were treated with irrigation,debridement,and vacuum sealing drainage.One dislocation and one suspected injury of the superior gluteal nerve also were observed and were treated conservatively.Conclusion Individualized customized cages appears to provide stable fixation and improve hip scores at short or mid-term follow-up.

Clinical study of autologous platelet rich plasma gel in arthroscopic rotator cuff repair:a randomized, controlled trial / 中华骨科杂志

Objective To investigate the effect of autologous platelet rich plasma (PRP) gel in arthroscopic rotator cuff re?pair. Methods All of 44 patients with rotator cuff tear undergent arthroscopic rotator cuff repair were randomly divided into two groups:PRP group (22 patients were received autologous PRP and hemocoagulase) and normal saline (NS) group (22 patients were received NS and hemocoagulase). All patients had the same accelerated rehabilitation protocol and were followed up in 1, 3, 12 months. Evaluation consisted of inflammatory reaction, wound healed, visual analogue scores (VAS), University of California at An?geles (UCLA) Shoulder Scores and American Shoulder and Elbow Surgeons (ASES) Scores. Results After operation, no inflam?matory reaction was in 20 cases of PRP group and 19 cases of NS group, mid inflammatory reaction 1 case in PRP group and 2 cas?es in NS group, moderate inflammatory reaction 1 case in PRP group and 1 case in NS group. Wound healed by first intention in all of PRP group and 21 patients of NS group. In PRP group, the preoperative, 3 months and 12 months postoperative VAS were 6.6±2.0, 3.4±1.8, 1.8±1.3, UCLA were 15.2±2.9, 24.3±2.7, 32.4±2.1, ASES were 35.6±12.4, 63.4±10.4, 92.3±7.5. In NS group, the preoperative, 3 months and 12 months postoperative VAS were 6.7 ± 1.9, 4.6 ± 1.9, 2.0 ± 1.2, UCLA were 14.8 ± 3.0, 21.2 ± 2.5, 31.7 ± 2.3, ASES were 32.7 ± 13.8, 55.8 ± 11.8, 90.7 ± 8.1. Three months postoperative VAS, UCLA, ASES were statistically signifi?cant differenece in PRP group and NS group. Twelve months postoperative VAS, UCLA, ASES were not statistically significant dif?ferenece in the two groups. Conclusion Using autologous PRP gel in arthroscopic rotator cuff repair can speed up the healing of operation incision with no adverse effect, reduce pain in the postoperation three months, accelerate the rotator cuff repair and re?covery of the function of shoulder joint. It has good short?term clinical effect.

Clinical study of platelet-rich plasma gel in total knee arthroplasty / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the effect of platelet-rich plasma (PRP) gel in total knee arthroplasty.</p><p><b>METHODS</b>From January 2011 to January 2013, 30 patients of total knee arthroplasty were received PRP (PRP group) and 30 patients won't received PRP(normal saline group).Routine drainage and functional exercise were applied to the two groups after operation. Postoperative drainage volume, inflammatory reaction, grade of wound healed, Hospital for Special Surgery (HSS) Score for knee, the Feller Score for patella and range of motion (ROM) for knee were evaluated.Independent samples t-test, grade data used rank sum test were used to compared two groups.</p><p><b>RESULTS</b>Postoperative drainage volume was (152 ± 22) ml in PRP group and (432 ± 35) ml in normal saline group. Postoperative drainage volume were statistically significant difference between two groups (t = 37.098, P < 0.05). At 4 days after operation, no inflammatory reaction was observed in 27 cases of PRP group and in 24 cases of normal saline group, mid inflammatory reaction in 2 cases of PRP group and in 4 cases of normal saline group, moderate inflammatory reaction in 1 cases of PRP group and in 2 cases of normal saline group.Wound healed by first intention in 30 patients of PRP group and in 29 patients of normal saline group (29/30), by second intention after 3 days of dressing change in 1 patient of normal saline group using 75% alcohol wet compressed. The adverse reaction rate was 3.3%. The average follow-up period was 16 months, ranging from 10 to 24 months. Three months postoperative HSS score for knee, scores of patellar, scores of anterior knee pain and ROM for knee were statistically significant difference in PRP group and normal saline group (t = 2.288, 2.097, 2.630, 2.104; all P < 0.05). Inflammatory reaction, grade of wound healed, final follow-up HSS score for knee, scores of patellar, scores of anterior knee pain and ROM for knee had no statistically significant difference between PRP group and normal saline group (P > 0.05).</p><p><b>CONCLUSIONS</b>Using PRP gel in total knee arthroplasty can reduce postoperative drainage volume, accelerate the healing of operation incision with no extra complications.It has good short-term clinical effect.</p>

The effect of platelet-rich plasma in anterior cruciate ligament reconstruction / 中华骨科杂志

Objective To investigate the effect of platelet-rich plasma (PRP) in anterior cruciate ligament (ACL) reconstruction.Methods From January 2010 to January 2013,40 patients with ACL ruptures who underwent arthroscopic ACL reconstruction with gracilis and semitendinosus tendon were randomly divided into two groups:PRP group and normal saline group.20 patients received graft soaked with PRP and hemocoagulase while 20 patients received graft soaked with normal saline and hemocoagulase.All patients were followed up in 1,3 and 12 months.Evaluation consisted of postoperative drainage volume,inflammatory reaction,grade of wound healed,anterior drawer test,Lachman test,pivot shift,Lysholm knee score and KNEELAX3.Results The average follow-up period was 18 months.Postoperative drainage volume was 142±24 ml in PRP group and 324±22 ml in saline group.The difference was statistically significant.At 4 days after the operation,no inflammatory reaction was observed in 18 cases of PRP group and in 16 cases of saline group,mid inflammatory reaction in 1 case of PRP group and 2 cases of sa line group,and moderate inflammatory reaction in 1 case of PRP group and 2 cases of saline group.Wound healed by first intention in 20 patients of PRP group and in 19 patients of saline group.The preoperative results of anterior drawer test,Lachman test and pivot shift were positive,while postoperative results were negative in both two groups.In PRP group,the preoperative and postoperative Lysholm knee scores of patients in 12 months were 39.8±8.9 and 92.1±2.7 points respectively.In saline group,the preoperative and postoperative Lysholm knee scores of patients in 12 months were 38.7±9.8 and 89.9±4.1points respectively.The differences were not statistically significant.KNEELAX3 measuring results:in PRP group,preoperative measurement was 9.4±1.2 mm in average,while measurement in 12 months postoperatively was 1.2±1.1 mm.In saline group,preoperative measurement was 9.6±1.3 mm,while measurement in 12 months postoperatively was 2.2±1.2 mm.The differences were statistically significant.Conclusion Using graft soaked with PRP in ACL reconstruction could reduce postoperative drainage volume,accelerate the healing of tendon-bone interface in the bone tunnel and the recovery of knee joint function.

Acute single-stage reconstruction of multiligament knee injuries using the ligament advanced reinforcement system

The purpose of the study was to report our early outcome in the management of multiligament knee injuries with the ligament advanced reinforcement system [LARS]. Between 2007 and 2010, 9 of 11 patients operated on for multiligament knee injuries were included in this study; 2 patients were excluded due to complicated neurovascular injuries, open knee dislocations and severe comorbidities. All patients were managed acutely [<3 weeks] by reconstructions of the cruciate and collateral ligaments with LARS ligament and were followed up for an average of 30 months [18-46 months]. The mean Lysholm score of the 9 patients at final follow-up was around 90 [range 88-94] with an average Tegner activity score of 5.5. The postoperative function of 1 case of KD-11 and 2 cases of KD-111 was rated as 'A,' while the remaining cases were rated 'B'. At final follow-up, minor osteoarthritic degeneration was detected in 1 case of KD-III and 2 cases of KD-IV. Superficial infection developed in 1 case, and no cases of knee synovitis and premature osteoarthritis were recorded. A creditable outcome at mean of 30 months' follow-up was obtained in acute single-stage reconstruction of uncomplicated multiligament knee injuries with LARS ligament

Proximal femoral nail antirotation for treatment of intertrochanteric fractures: an analysis of 112 patients / 中华创伤杂志

Objective To investigate the clinical value of proximal femoral nail antirotation ( PFNA) in treatment of intertrochanteric fractures.Methods From April 2007 to July 2009,112 patients with intertrochanteric fractures were treated by using PFNA.There were 34 males and 78 females,at mean age of 76 years.Of all,80 patients were with type 31-A2 fracture and 32 with type 31-A3 fractures according to AO classification.According to Singh index classification,there were 4 patients at grade Ⅰ,21 at grade Ⅱ,70 at grade Ⅲ and 15 at grade Ⅳ.The fracture was caused by low-energy injury in 97 patients and by high-energy injury in 15.The Salvati-Wilson score was used to evaluate the hip function postoperatively.Results Ninety patients received 12-24 months follow-up (average 18.6 months).The Salvati-Wilson score was (29.98 ± 5.18 ) points.The result was excellent in 41 patients,good in 40,fair in 6 and poor in 3,with excellenct rate of 90％.The introduction of the nail in operation was difficult in 22 patients,of which 3 patients suffered femoral cortex rupture.Displacement or separation of the fracture segments occurred in 34 patients and distal locking difficulty in nine during the screw blade tapping process.Local complications included hip pain in 21 patients,thigh pain in 4,apparent coxa vara in 2 and delayed healing in 7.There were no cutting-out or femoral shaft fractures no matter what type of Singh index was.The systemic complications included cardiovascular and cerebrovascular disease in one patient,pulmonary infection in four,deep vein embolism in one and perineum congestion or swelling in seventeen.Conclusion PFNA is effective in treating intertrochanteric fractures especially osteoporotic fractures,but delayed healing of the fractures and the mismatch between the intramedullary nail and the proximal femoral morphology remain to be addressed.

The total hip arthroplasty for protrusio acetabuli / 中华骨科杂志

Objective To evaluate the clinical outcome of total hip arthroplasty (THA) for protrusio acetabuli. Methods Between 2003 to 2008, 31 patients(35 hips) with protrusio acetabuli were treated with THA, including 16 males (18 hips) and 15 females (17 hips). The age ranged from 36 to 71 years (average age 52.2 years). The femoral heads were moved out with retrograde method when necessary via posterior-lateral hip incision. The acetabular loops and bottoms were prepared respectively. Auto-bone grafting was used to repair acetabular defects and cementless prostheses were planted with press-fit skills. At follow-up visit,the hip functions were evaluated by Harris score. The loosening, re-protrusion and the union of graft bone was judged by X-ray. Results The mean follow-up was 46.5 months (19-152 months). One patient developed DVT on the second day post-operatively who recovered well after anticoagulation treatment. One patient complained of gentle thigh pain which disappeared at 6 months. No other complication was found. The mean Harris scores had improved from 48.9±6.5 pre-operatively to 91.2±5.7 post-operatively. All prostheses acquired bone stabilization with no sign of loosening and re-protrusion and the grafts bone were healed at a mean 6 months according to X-ray. Conclusion THA with acetabular bone grafting and cementless component for protrusio acetabuli have acquired excellent results and prevented loosening and re-protrusio effectively.

Clinical Trial on the Role of Tuina in Rehabilitation Therapy Following Total Hip Replacement / 针灸推拿医学（英文版）

Objective: To observe the clinical effect of tuina in rehabilitation following total hip replacement. Methods: 60 cases were randomly allocated into a treatment group and control group, 30 cases in each group. Cases in the treatment were treated with combined mina and rehabilitation, while cases in the control group were treated with rehabilitation alone. All treatment retained for two weeks. The results were observed 7 d, 2 weeks and 6 weeks following the total hip replacement using Harris scale and Hamilton Anxiety Rating Scale (HAMA).Results: For Harris scale, there were significant intra-group differences in different time frames (P＜0.05); there were no statistical differences between the two groups 1 d, 7 d and 6 weeks following the total hip replacement (P＞0.05); and there were statistical differences between the two groups 2 weeks following the total hip replacement. For HAMA scale, there were significant intra-group differences in different time frames (P＜0.05); there were no significant differences between the two groups 1 d following the total hip replacement; and there were substantial differences between the two groups 7 d, 2 weeks and 6 weeks following the total hip replacement. Conclusion: In a given unit time, combined mina and rehabilitation is superior to rehabilitation alone in improving the patients' post-operative pain, articular range of motion and anxiety.

Autologous bone marrow stem cell transplant versus autologous iliac bone graft for bone nonunion treatment / 中国组织工程研究

BACKGROUND: The bone marrow stem cell (MSC) transplant treatment have the obvious superiority to tradition graft treatment for bone nonunion, but how to obtain the concentrated and highly effective bone marrow mesenchymal stem cell, as well as the dose-effect relations to fracture healing need further discussions. OBJECTIVE: To observe the curative effect of bone nonunion by using autologous MSC transplant treatment, and to compare with autologous iliac bone graft.DESIGN, TIME AND SETTING: Randomized controlled analysis was performed from January 1999 to June 2005 in the Affiliated Second Hospital of Hebei Northern College.PARTICIPANTS: The admitting 140 patients with humerus and tibia fracture were divided into 2 groups at random, autologous iliac bone graft group and autologous MSC transplant group, with 70 patients in each group. METHODS: Under aseptic condition, autologous MSC transplant group received puncture through posterior superior iliac spine, extracting bone marrow 10-20 mL from different spots, separating MSC using the density gradient centrifugation method, and counting as 4×10~9 nucleated cells/mL under the microscope for later use. In the autologous iliac bone graft group, bone fracture end was implanted with the suitable amount of iliac bone, while autologous MSC transplant group with the mixture of decalcified bone matrix and MSC, followed by suture. After the transplantation, external fixation may assist for 4-6 weeks according to the fixed degree of internal fixation.MAIN OUTCOME MEASURES: ① Bone callus formation and pain conditions in 2 groups at different time points after transplantation. ② Comparison of bone healing time between 2 groups. ③ Adverse events and side effects.RESULTS: According to intention-treatment analysis, experimental adopted 140 patients of humerus and tibia fractures, who all entered the final analysis. ① Bone callus formation and pain at different time points post-surgery: At 1 month after transplantation, bone callus formation in the fracture end was not obvious in autogenous iliac bone graft group, and could be seen in autologous MSC transplant group, both groups of fractures exhibited tenderness. At 2 months after transplantation, bone callus formation was observed in autogenous iliac bone graft group, fracture tenderness was relieved compared with the previous condition; in autologous MSC transplant group, a large number of bone callus formed, fracture tenderness was not obvious. At 3 months after transplantation, there were a large number of bone callus formations in autogenous iliac bone graft group, with slight fracture tenderness; in the autologous MSC transplant group, continuous bone callus formation appeared, without fracture tenderness. ② Bone healing time: The average healing time of autologous MSC transplant group was significantly shorter than autogenous iliac bone graft group [(5.5±1.5), (8.0±2.0) months, P < 0.05]. ③ Adverse events and side effects: Except 4 patients had iliac bone pain, all patients during the treatment had no infection and other complications, there were no re-fracture occurred at the follow-up of 8 months.CONCLUSION: The autologous MSC transplant treatment of exhibits a short duration and good effect for bone non-union, has obvious advantages over traditional bone graft.

Effect of Percutaneous Autogenous Bone Marrow Stem Cell Transplant on Bone Nonunion / 中国康复理论与实践

@#Objective To investigate the clinical effect of percutaneous autogenous bone marrow stem cell transplant on bone nonunion. Methods 140 patient with bones nonunion were divided into the autogenous bone transplants (A) group and the autogenous bone marrow stem cell transplant (B) group, with 70 cases in each group. They were assessed 2 and 5 months after operation. Results A few calluses could be observed at the end of fracture in 42 cases in group A 2 months after operation, and massive callus formation could be observed in 46 cases 5 months after operation. However, massive callus formation could be observed in 60 cases in group B 2 months after operation, and continual callus formation could be observed in 45 cases 5 months after operation. The mean healing time was (8.4±1.8) months in group A, and (6.5±2.0) months in group B (P<0.05). No side-effects have been observed during the treatment. Conclusion The percutaneous autogenous bone marrow stem cell transplant is more effective on bone nonunion compared with the traditional treatment.

Comprehensive clinical assessment on imaging diagnosis of low back pain / 中国矫形外科杂志

Objective To pursue the appropriate selection of radiographic examinations of low back pain and to reduce the expenses. Method In this study,61 cases of imaging tests were studied,including 38 cases of lumbar disc herniation,10 cases of lumbar spondylolisthesis,4 lumbar stenosis,4 lumbar infection and 5 lumbar neoplasm. Result Correct diagnosis was based on the clinical signs and symptoms.Imaging findings had its value only when basing on them.Conventional roentgenogram offered a cheap evaluation and high spatial resolution of bony structures.And it could give a clue to take further imaging studies.Low back disorders could be inferred from the contrast column defect of dura sac and nerve root sheath in the myelography.In the diagnosis of disc herniation,its limitations existed at far lacteral and L5S1 disc herniation.Computed tomography,a cross-sectional imaging modality,allows direct visualization of the bony structure of the spine.But routine imaging could only cover a limited number of levers.Another limitation was the difficulty in distinguishing the soft tissue changes in the spinal canal with the similar CT values.CT-myelography was performed to delineate more clearly the bony and soft tissue anatomy,and could determine whether lesions were medullary,intradual or extradual in location.MR imaging provided the larger anatomic region in multiple planes with high spatial resolution of soft tissue.One limitation of MR imaging was relatively low spatial resolution of bony structure. Conclusion Of all imaging studies conventional roentgenogram is the most important and the most fundamental.It could not be substituted by myelography,CT,CT-myelography,and MR imaging,which have their designated own roles respectively in the clinical decision-making process and in general were more complementary than competitive.

Effect of melittin on apoptosis and necrosis of U2 OS cells / 中西医结合学报

OBJECTIVE: To study the effect of melittin on apoptsis and necrosis of osteosarcoma cell line U2 OS in vitro. METHODS: Osteosarcoma cell line U2 OS was treated with melittin. The growth and proliferation was observed by MTT assay and cell counting, and the necrosis was estimated by Trypan blue staining. The cell apoptsis, Fas and Apo2. 7 expression were detected by cytometer. RESULTS: The data showed that melittin could inhibit the proliferation of U2 OS dose-dependently at 16 and 64 mg/L. Cell apoptsis was detected by cytometer, when the cells were treated by 16 mg/L and 32 mg/L of melittin respectively, and the percentages of Fas and Apo2. 7 positive cells were increased. CONCLUSION: Melittin inhibits the proliferation of osterosarcoma cell line through up-regulating Fas expression and inducing apoptsis.

A transmission electron microscopic study on biological reaction of synovitis in duced by wear particles from joint prosthesis / 中华创伤杂志

Objective To explore the cytological mechanism of bi ological reaction of prosthetic loosening mediated by wear particles from joint prosthesis. Methods Three special particles of UHMWPE, Ti- 6Al-4V and Co-Cr-Mo with the same average size of 2.5 ?m were injected respe ctively into rabbit knee joint to induce synovitis, in which the changes of syno vial cells and its cytoplasm as well as ultrastructure were observed by transmis sion electron microscopy. Results Three kinds of particles mainly induced type A synovial cell reaction with proliferation of subsynovial h istocytes. Wear particles and lysosomes existed in the cytoplasms of the synovia l cells and histocytes. Co-Cr-Mo particles could also accelerate infiltrating reaction of regional cytoplasms. Conclusions The biological effect of wear particles inducing prosthetic loosening is mainly non-immunolog ic inflammatory reaction. Certain immunologic factors may involve in biological reaction induced by Co-Cr-Mo wear particles.

The reconstruction of massive bone defect in acetabulum in revision surgery / 中华骨科杂志

Objective To propose measures to reconstruct the massive bone defect in acetabulum in revision hip arthroplasty on the basis of the experience in the cases treated by the authors. Methods Thirty- two hips of 33 hip revision cases with massive bone defect being operated on by the first author were summarized and analyzed. The patients included 17 males and 15 females, with the age of 40 to 90 years. 28 cases (29 hips) underwent revision for the first time, 2 cases (2 hips) for the second time,1 case (1 hip) for the third and the other 1 case (1 hip)for the fourth time. The primary surgery were artificial femoral head replacement in 8 cases (8 hips) and total hip replacement in 24 cases (25 hips). Except of 2 saddle protheses replacement, bone grafts, mainly cancellous bone grafts, were used in 31 hips, of which 22 hips were non- structural bone grafts and 9 hips were allografts of femoral head or autograft of ilium. After grafting, ready- made acetabular prostheses were implanted in 9 hips, while special prostheses were used in 24 hips, chiefly computer- aided custom- made acetabular prostheses, including winged prostheses, 2- layer metal mesh, acetabular reinforcing rings (ARR), bi- spherical prostheses, crested prostheses and saddle type prostheses. Results In the course of 0.5 to 11 years' follow- up, re- displacement or relapse of bone absorption was not found in any of the cases. The Harris hip function score rose to 54－ 89 from the pre- operative level of 17－ 48. The computer- aided custom- made acetabular prostheses could better meet the requirements of different conditions of disease, thereby reducing the difficulties of surgery. Conclusion Special prostheses have the advantages of better compatibility with the individual requirements, prevention of displacement or collapse of the bone graft and higher primary stability. The proper application of bone graft and choice of suitable prosthesis to achieve the reconstruction of acetabular fossa and the integrity of acetabular circumference will markedly improve the success rate of revision surgery.

Computer aided design of individualized hemipelvic prosthesis and its clinical application / 中华骨科杂志

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.

The balance of the soft tissue in total knee arthroplasty for patients with knee flexion contracture / 中华骨科杂志

Objective To explore the way of soft tissue balance in total knee arthroplasty for patient with flexion contracture. Methods A relevant protocol of soft tissue balance was designed and used in 33 TKA cases with knee flexion contracture of at least 20? (from 20? to 60? ). Tight medial collateral ligament or lateral collateral ligament was released firstly, followed by the release of posterior capsule. Osteotomy or a second osteotomy at tibial or femoral side were performed at final step. Results Twenty cases (60.6%) whose flexion deformities could be corrected solely by soft tissue release, the rest 13 (