Disruption of blood supply to the femoral head and subsequent hypoxia are implicated in the pathogenesis of osteonecrosis of the femoral head(ONFH),which frequently leads to the progressive collapse of the femoral head,thus causing degenerative arthritis of the hip joint.But the pathophysiology of osteonecrosis of the femoral head has not been completely elucidated.It is accepted that steroids and alcohol intake are two most common causes of ONFH.Now many theories have been proposed to decipher the etiology and pathogenesis of ONFH,including abnormal lipid metabolism,elevated intraosseous pressure,intravascular coagulation,second collision theory,etc.The purpose of this review is to summarize the etiology and pathogenesis of osteonecrosis of the femoral head.

[Objective]To investgate the expression of vascular endothelial growth factor in osteonecrosis of the femoral head during the repairing with biodegradable strontium-doped calcium polyphosphate in glucocorticoid-induced rabbits.[Method]Twenty mg/kg methylprednisolone was injected into right gluteus medius muscle at intervals of 24 hours for three times in 21 adult male Japanese white rabbits.Three rabbits were killed randomly at 2 weeks after methylpednisolone injection,both the femora and humeri were histologically examined for the presence of osteonecrosis. The remaining 18 animals with a total of 36 cylindrical 2.5?5 mm femoral head defects were created following the trapdoor procedure. Eighteen animals with femoral head bone defects were randomly divided into three groups. Group A:the defects filled with strontium-doped calcium polyphosphat,Group B:the defects filled with calcium polyphosphate and Group C:the defects filled with autologous cancellous bone alone. Roentgenographic and histological examinations were performed postoperatively. Finally,immunohistochemical analysis using monoclonal antibodies anti-VEGF was performed.[Result]No hip joint dislocation occurred. In Group A,the results of VEGF expression had a significantly difference from those in the other groups 12 weeks after operation. Most of the biodegradable strontium-doped calcium polyphosphate was resorbed and was largely replaced by newly formed trabecular bone at 12 weeks. While in Group B,a major part of defect were repaired. New formed trabecular bone in the defect was very thin. In Group C,morsellized cancellous bone was completely surrounded by fibrous and newly formed trabecular bone. [Conclusion]VEGF expression in the defect of osteonecrosis of the femoral head during the repairing with biodegradable strontium-doped calcium polyphosphate may play a role in stimulating vascular invasion and granulation tissue formation.This may be an important step toward facilitating the resorption in the osteonecrosis,thus impooring the repairing proceduce of femoral head defect.

[Objective]To analyze the early diagnosis and treatment of the popliteal artery injury associated with the dislocation and fracture of the knee.[Method]A total of 71 cases of popliteal artery injury associated with the dislocation and fracture of the knee were treated from March 1998 to May 2005.Properative(vascular examization) and operative(methods of arterial repair,venous repair-ligation,anticoagulation-thrombolytic therapy,fracture reduction and internal fixation,fasciotomy) treatment were studied.[Result]Totally 15 cases were primary amputation and 56 cases were performed vascular repair and the fractures and dislocations were reduced and fixed by internal or external fixation.Two cases had thrombosis at the repaired site confirmed by Doppler and had to perform second operation to remove thrombus and repair the popliteal by autograft of the saphena magna vein.At the follow-up,2 cases had chronic osteomyelitis and 2 cases had traumatic arthritis.[Conclusion]It is postulated that a rational and prompt diagnosis and treatment of popliteal artery injury associated with dislocation and fracture around the knee would decrease the adverse effects of ischemia and reduce the overall morbidity.

Objective To retrospectively analyze the diagnosis and treatment of the extra-articular inflammatory pseudotumor after well-fixed metal-polyethylene total hip arthroplasty (THA).Methods From March 2006 to June 2011,7 patients (7 hips) who presented with a progressive pain and/or swelling,discomfort in groin or upper thigh after metal-polyethylene THA were admitted to our hospital.There were 2 males and 5 females,with an average age of 48.8 years (range,32-65 years).All 7 patients were identified with a periprosthetic osteolysis at the acetabular and/or femoral components and a mass in the iliac fossa or the thigh; however,the components were all well-fixed.The masses were confirmed by CT scanning and/or ultrasound examination.The revision procedures were done through ilioinguinal approach and posterior-lateral approach,and the pseudotumors were excised and osteolytic lesions were debrided and packed tightly with morselized cancellous allograft.The liner and femoral head were also exchanged at the same time.Clinical and radiographic outcomes of revision THA were evaluated.Results All 7 patients were followed up for 3-42 months (average,30 months).At final follow-up,all hips were functioning well and the average Harris hip score was 92.4.All acetabular components remained radiographically well-fixed.All cavitary defects had complete radiographic incorporation of the bone grafts.There were no new pseudotumor or osteolytic lesions identified,and no revision of the components.Conclusion The presence of abdominal or pelvic pseudotumor in patient with a THA may be associated with polyethylene wear.Once the extra-articular pseudotumor and the periprosthetic osteolysis are identified,the surgical treatment,including pseudotumor excise,osteolytic lesion debride and bone defect grafting and bearing surface exchange,can achieve retention of well-fixed components.

Objective To study the early diagnosis and treatment of the blunt popliteal artery injury without fracture or dislocation of the knee. Methods From March 1984 to November 2002, 11 cases of blunt popliteal artery injury without fracture or dislocation of the knee were diagnosed as earlier as possible based on clinical analysis including injury condition, clinical examination and Doppler-Duplex ultrasonography and treated with early repair of the injured arteries, intraoperative or postoperative anticoagulation, immediate fasciotomy and thorough debridement of the ischemic and necrotic muscules and soft tissue. Results There was one with amputation and two with slight dysfunction of the lower extremity, as did not affect normal daily lives. One case had serious dysfunction of the lower extremity due to thrombosis at the injured popliteal artery after first operation and had to receive second operation so as to remove thrombus and repair the popliteal by autograft of the saphena magna vein. However, there left severe function disorder of the extremities. Conclusion A rational and prompt diagnosis and treatment for blunt popliteal artery injury without fracture or dislocation of the knee will decrease the adverse effect of ischemia and reduce overall morbidity.

Objective To investigate the efficacy and safety of tranexamic acid on bleeding in rheumatoid arthritis (RA) patients undergoing total hip arthroplasty (THA). Methods A retrospective study was performed in 197 RA patients (Steinbrock?er III-IV) following primary unilateral THA from June 2012 to June 2014. The patients were divided to three groups based on the regimen of tranexamic acid:68 patients received a single intravenous dosage of 15 mg/kg tranexamic acid 20 min prior to opera?tion (single dose group);74 patients received an intravenous dosage of 15 mg/kg preoperatively and a second dosage of 10 mg/kg 3 hours postoperatively (repeated dose group);the other 55 patients didn't receive tranexamic acid (control group). The primary out?comes were total blood loss, transfusion rate, the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE). The sec?ondary outcomes were postoperative drainage, hemoglobin (Hb) drop on third day postoperatively and other wound related compli?cations. Results There was less total blood loss (816.80 ± 245.09 ml vs 975.15 ± 216.33 ml vs 1 295.68 ± 263.85 ml), drainage (221.60 ± 70.05 ml vs 337.20 ± 113.10 ml vs 479.74 ± 120.66 ml), transfusion requirement (5.41%vs 10.29%vs 25.45%) and Hb drop (2.71±0.74 g/dl vs 3.18±0.62 g/dl vs 3.83±0.70 g/dl) in experimental group when compared with control group. And the effect was better in repeated dose group, with less total blood loss (816.80 ± 245.09 ml), less transfusion requirement (5.41%) and less postoperative drainage (221.60±70.05 ml). No episode of DVT or PE occurred in either group. There were 8 wound complications in single dose group, 6 in repeated group, and 8 in control group, and there were no statistically difference. Conclusion Intrave?nous administration of tranexamic acid was effective and safe on decreasing blood loss and transfusion requirement in RA patients following THA. Compared with a single dosage of tranexamic acid preoperatively, a second dosage of tranexamic acid 3 hours post?operatively was recommended.

Objective To retrospectively analyze the short-term clinical effects of the two-stage cementless total hip arthroplasty in the treatment of chronic infection after the internal fixation of the adult proximal femoral fracture.Methods From June 2006 to June 2011,9 patients who had suffered a chronic infection after an internal fixation of the proximal femoral fracture,including 8 males and 1 female,aged from 31 to 74 years (average,52.6 years),were treated with two-stage cementless total hip arthroplasty.There were 3 cases of femoral neck fracture,and 6 cases of intertrochanteric fracture.In the first stage,after surgical debridement and thorough removal of all the implants,an antibiotic-loaded cement spacer was implanted.All patients postoperatively underwent intravenous and oral antibiotics,and the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were tested.When the values of ESR and CRP become normal,the second stage operation using cementless components was performed.Results The presence of infection was confirmed by a positive culture of joint fluid obtained intraoperatively in two cases;one case was staphylococcus aureus and another one was staphylococcus epidermidis.The second stage arthroplasty was performed 6-14 months (average,9 months) after the first stage operation.All 9 patients were followed up for an average of 23.2 months (range,6 to 50 months).No recurrent infection,component loosening,bone osteolysis and cement spacer or component dislocation occurred.The Harris score improved from 74.6 (range,64 to 86) before the first stage operation to 90.9 (range,86 to 97) at the final follow-up.Conclusion The two-stage cementless total hip arthroplasty is an effective strategy for the treatment of chronic infection after the internal fixation of the adult proximal femoral fracture.

Objective To evaluate the results of using focus clearance and morselized bone graft to treat a well-fixed socket osteolysis after total hip arthroplasty (THA) during cementless acetabular revisions.Methods From March 2006 to March 2009, 23 patients (23 hips) who had an acetabular revision hip arthroplasty of well-fixed socket for osteolysis were retrospectively reviewed, including 13 males and 10 females with an average age of 46.6 years (range, 39-54), and the mean interval from primary to revision THA was 5.5 years (range, 4.6-7.4). The preoperative Harris hip score was 74. The operative technique included debridement of soft tissues with removal of granulomata and packed tightly with morselized cancellous allograft through ilioinguinal approach, and exchanging the liner and femoral head through the posterior-lateral approach of the hip. Results The mean duration of follow-up after revision was 28 months (range, 8-38). At final follow-up, all hip were functioning well and the average Harris hip score was 93.8. Osteogenesis in bone graft were well-developed in 16 patients. Twelve bone grafts were completely incorporated into surrounding bone through creeping substitution. All acetabular components remain radiographically well-fixed and no loosening and shifting. There were no new osteolytic lesions, ectopic ossification, deep venous thrombosis, hip dislocation or infection during follow-up. Conclusion Our revision strategies included debridement and bone grafting, a revision of femoral heads and polyethylene liner and retention of the cups and femoral stems. The method can reduce the amount of the wear particle from polyethylene. The short-term outcome is excellent.

Objective To investigate the middle-term results of anti-protrusio cage combining with allograft bone graft for revision arthroplasty of Paprosky type Ⅲ acetabular bone defect.Methods A retrospective analysis was done for 19 patients (20 hips) with Paprosky type Ⅲ acetabular bone defect who received acetabular revisions using anti-protrusio cage from January 2002 to December 2009.There were 11 males and 8 females,aged from 42 to 76 years (average,57.4 years).There were 7 hips (35％) of Paprosky type ⅢA acetabular bone defect,and 13 hips (65％) of type ⅢB.The follow-up time was (5.8±2.4) years.Hip function of patients was judged by Harris hip scores pre-and post-operation.The outcome of acetabular prostheses and bone grafts were assessed by radiologic evaluation.The five-year cage failure-free survival rate was assessed by Kaplan-Meier survivorship analysis.Results The Harris hip scores improved from preoperative 14.6±4.3 to 83.5±7.9 at the final follow-up.Lower limb discrepancy improved from preoperative (26.3±9.1) mm to postoperative (1.2±3.4) mm.The hip rotation center was reconstructed from preoperative(23.6±7.4) mm up-toward and (4.4±14.7) mm lateral-toward dislocation to inside Ranawat triangle.All the allograft bone was incorporated with host bone.None of cage displacement,screw fracture,progressive radiolucency and cement fracture was observed.Mild allograft bone resorption was observed in 3 hips (15％).There was no moderate or severe bone resorption found at the final follow-up.The five-year cage failure-free survival rate was 100％ (95％ CI,0.95-1.00).Conclusion The revision using anti-protrusio cage combined with allograft bone graft shows satisfying middle-term clinical and radiological results in the treatment of Paprosky type Ⅲ acetabular bone defect.

Objective To investigate the perioperative management,coagulation factor regulation in total knee arthroplasty (TKA) for hemophilia arthritis and evaluate its short-term clinical efficacy.Methods A retrospective study was performed in hemophilia arthritis patients who had undergone TKA from March,2009 to March,2014.Patients with type A hemophilia received Lyophilized Human Factor Ⅷ,and type B hemophilia patients received Prothrombin Complex.Perioperative accurate dosage of coagulation factor was determined by preliminary test.AORI T1,T2 bone defects were filled with PMMA,and severe contained AORI T3 defects were fixed with impaction allograft and screws,and for non-contained AORI T3 bone defects,structural allografts and stem extension may be considered.Knee function was evaluated by HSS score,and imaging change was evaluated by anteroposterior and lateral radiographs of knee at latest follow-up.Results Eight patients (10 knees) were included with a mean age of 38.3±5.0 years,in which 6 were type A,and the other 2 were type B.Preoperative APTT was 63.9±4.0 s,and coagulation factor activity was 2.6％±0.9％.All the patients had flexion deformity with extension of-12.0°±5.9° and flexion of-88.0°± 11.4°.Three patients (3 knees) had valgus deformity with-3.0°±5.4°,and 2 patients (4 knees) had varus deformity with-4.5°±6.0°.All the 8 patients were followed for a mean of 14.3 months.The range of motion was improved with 0°-98.5°±6.7° at latest follow-up,and the postoperative HSS score was 88.3±4.6 compared with 42.3±10.9 preoperatively.Bone-grafting was survival,and no loosening of prosthesis or screws were detected from X-ray at latest follow-up.Conclusion The early results of TKA in Hemophilia arthritis patients are satisfactory.Preoperative preliminary test was helpful to determine the accurate dosage of coagulation factor.A stable high level of coagulation factor was vital to control bone-cement bleeding and make prosthesis stable.Tibial bone defects involving ＜ 1/3 area and ＜ 1 cm in depth could be filled with PMMA,and impaction allograft and screws could be used to fix severe contained bone defects.For segmental bone defects,except of structural allograft,stem extension was recommended to reduce stress and increase stability.