Objective To evaluate mid-term clinical and radiographic outcomes associated with cementless total hip arthroplasty(THA) in a consecutive series of patients with osteonecrosis of the femoral head. Methods This study examined the mid-term (equal to or more than 5 years) results of THA. From January 1998 to March 2001, a series of 71 patients (80 hips) who had undergone THA with cementless components in our hospital were involved in this study. All patients were evaluated both clinically and radiographically. Clinical outcomes were evaluated according to Harris evaluation score. Components migration, bone changes around the implant, the polyethylene wear rate and direction of the acetabular polyethylene wear were measured radiologically. Kaplan-Meier analysis was performed to evaluate the survival of the femoral and acetabulum components. End point was radiographical loosening or revision of the acetabular component, and revision of the femoral component for any reason. Results 62 hips in 54 patients were followed up at least 5 years. The mean Harris hip score improved from preoperation (44.0?8.4) points to (92.4?5.7) points at the time of final follow-up. No component was seen to be loose radiographically or had been revised because of any reason at the time of final follow-up. Only one focal area of pelvic osteolysis in one patient and twelve small focal areas of femoral osteolysis in another patient were identified. The mean linear wear rate was (0.125?0.074) mm/year. When loosening was used as the end point for failure, the survival rate of the acetabular and femoral components was 1.0 (95% confidence interval, 0.98 to 1.00) in both groups. Conclusion Cementless THA in patients with osteonecrosis of the hip had a satisfactory clinical and radiographic outcome at a minimum of five years follow-up. Because polyethylene wear and osteolysis can not avoided, radiographical follow-up for cementless components is very important.

[Objective]To evaluate the safety and efficacy of total hip resurfacing arthroplasty in treating osteoarthritis secondary to congenital dysplastic hip.[Method]From May 2005 to June 2005,13 hips in 12 cases with osteoarthritis secondary dysplastic hip were adopted in this study.There were 8 females and 4 males,aged from 30 to 59 years,average 47 years.All the 13 hips were subluxation according to Hartofilakidis classification system.Posterolateral approach was used during operation and all the acetabular cups were reconstructed at the true acetabular location.The pronthesis were cementless acetabular cup and cement femoral head.[Result]The average operation time was 110 min,blood loss volume was 387 ml during operation,drainage volume was 200 ml and the extremity was lengthened for about 9 mm.All the incision healed well and there have not any complications such as femoral neck fracture,infection,dislocation and neurovascular injury.Follow-up for 12 to 13 months,all the joints had good or excellent clinical results.The average range of motion of the hip:flexion improved from 106.7? to 120?,abduction improved from 25.8? to 46.4?,external rotation improved from 20.8? to 45?,internal rotation improved from 3.3? to 28.6?.The Harris score increased from 42 preoperatively to 96 postoperatively.Radiographically,the positions of the prostheses were normal,the average abduction angle of the cup was 39?,the average stem-shaft angle wes 141?,the positions of acetabular rotation centre were moved down and medially for average 9 mm and 11.5 mm respectively,the acetabular superolateral bone coverage of the hips was 89.5%,no radiolucent line was observed.[Conclusion]Total hip resurfacing arthroplasty has got good short-term results in the treatment of osteoarthritis secondary to dysplastic hip.Because of the less quantity and short follow-up time,the long-term results and indications for other kinds of dysplastic hip are worthy of further studying.

Objective To discuss the therapeutic method of the chronical septic hip replacements with discharging sinuses. Methods Ten cases of infected hip replacement with discharging sinuses, including 6 males and 4 females with a mean age of 59 years old (from 48 to 65 years old ) were reported. The preoper ative mean Harris score was 31 (range 26 to 38), mean erythrocyte sedimentation rate (ESR) was 56 mm/h (38 to 74 mm/h). Cultures and sensitive test before and d uring operation were both carried out. One stage revision was performed in eig ht cases, two stage revision was performed in two cases. Results Preoperation microorganism cultures of joint aspiration or pus in sinus were positive in eigh t cases and negative in two cases; six had staphylococcus and two Gram negative microorganism. Intraoperation microorganism cultures were positive in nine cases and negative in 1 case; seven had staphylococcus and two had Gram negative. Acc ording to the results of preoperation microorganism cultures, six cases of staph ylococcus infection two negative cases of microorganism culture were treated wit h one stage revision, the other two cases of infection by Gram negative microo rganism had undergone two stage revision. No recurrence was found after 19 mon ths (8 to 30 months) follow up. ESR after operation decreased to normal range. Mean Harris score increased significantly to 82.5 (78 to 89) after revision(t- test, P

Objective To summarize the experiences of total hip replacement in the treatment of osteoarthritis secondary to congenital dislocation of hip in adults. Methods From April 1998 to April 2000, fourteen hips in nine adult patients with osteoarthritis secondary to congenital dislocation of hip undergone total hip replacement were included in this study. There were seven females and two males. The age of the patients at surgery ranged from 27-53 years (mean, 45.56 years). Five patients underwent bilateral total hip replacements and 4 had unilateral total hip replacement. Results The incision healed smoothly. The duration of follow up ranged from 6 months to 2 years. All the patients could walk independently after the surgery. They could take care of themselves and restored to previous job. The average Harris score was increased from 33.93 to 89.21 points after the surgery. Conclusion Total hip replacement is an effective method in the treatment of osteoarthritis secondary to congenital dislocation of hip in adults. The four special problems encountered in the procedure such as the position of the acetabular component, the implantation of the femoral stem, the reconstruction of the abductor power, and correction of the leg length discrepancies should be considered. It is a challenging work to the orthopaedic surgeon and the careful preoperative planning is recommended.

[Objective]To observate the successive status of chondrocyte apoptosis after impacting injury of articular cartilage by TUNEL marking method and transmission electron microscope(TEM).[Method]Fifty-six New Zealand adult rabbits were divided randomly into low-energy and high-energy two groups,each group was 28.Femoral medial condylar cartilage of one side was injuked by impacting in experimental group,the opposite side as control group.Four rabbits were killed and their medial femoral condylar cartilages were taken at each of the following intervals:4 days,1,2,4,8,16,32 weeks after impacting injury.The specimens were observed as pathology histological sections and strained by TUNEL to measured the rate of chondrocyte apoptosis.[Result]In early stage of post-injury,the rate of chondrocyte apoptosis in and high-energy is significantly higher than that of control group.After 4 weeks,the rate of chondrocyte apoptosis decreases to the level of that of control group in low-energy.In high-energy group,the rate of chondrocyte apoptosis is constantly upgraded-phase,higer significantly than the level of that of control group.[Conclusion]In early stage of post-injury,the rate of chondrocyte apoptosis in low and high-energy was significantly higher than that of control group.After 4 weeks,the rate of chondrocyte apoptosis decreased to the level of control group in low-energy.In high-energy group,the rate of chondrocyte apoptosis is constantly upgraded-phase,higer significantly than the level of control group.

[Objective]To assess the early diagnosis and treatment and outcome of patients with crush syndrome in earthquake disaster.[Method]We conducted a retrospective analysis of 27 patients with crush syndrome and subsequent acute renal failure (ARF) and wound complication who were treated in our university hospital.All of patients had been extricated from buildings that collapsed in the Wenchuan earthquake.Crush injury involved the upper extremities and low extremities.Each patient received intravenous fluids and diuretic drugs.Twenty-one patients received hemodialysis.Emergency fasciotomy performed in 11 patients and amputation were performed in 16 patients,4 to 102 hours after extrication.[Result]No patient died.Twenty-one patients among the ARF patients were retracted from hemodialysis.Among the patients who were performed fasciotomy or amputation,13 patients had wound complication including infection,however,the wounds in 10 patients were healed by dressing change,debridement and coordinate treatment with ICU and related subjectives.[Conclusion]Crush syndrome requires urgent recognition and prompt surgical treatment with simultaneous measures to control hyperkalemia and ARF.Wound healing is a difficult task for the crush syndrome patients.The authors believe that immediate intensive care therapy and multisubjective coordination would improve the survival rate.

[Objective]To analyze the effect of renal replacement therapy on the wound of crush syndrome patients,and to provide better clinic evidence for scheduling the therapy strategy of crush syndrome.[Method]The clinic data of patients suffering from crush syndrome during Wenchuan earthquake were collected and classified into Group A treated by renal replacement therapy and Group B theraped by other treatments except renal replacement therapy.Wound infection rate,wound active artery bleeding occurrence,and the volume of oozes in fasciotomy wound between these two groups were compared.[Result]There was statistically significant difference in the rate of wound infection between Group A and Group B(P=0.006).The most common pathogens were acinetobacter spp,pseudomonas aeruginosa,and enterobacter spp in Group A,and these pathogens were all multi drug-resistant.There was statistically significant difference in the volume of oozes in incisive wound between these two groups(P=0.000).[Conclusion]Renal replacement therapy would increase the volume of oozes,raise the rate of wound infection,and be susceptiblely infected by multi drug-resistant pathogen.

[Objective]To investigate the pathological change of articular cartilage after impacting injury.[Method]Fifty-six New Zealand adult rabbits were divided randomly into low-energy and high-energy groups,with 28 rabbits in each group.One side of hind limb was designed as experimental side and the opposite one as control side.Four rabbits were killed at 4 days,1,2,4,8,16 weeks after impacting injury.Histological sections of the specimens were observed and stained by HE and Safranin O.the values of gray scale were obtained by imaging analysis.[Result]In low-energy group,the Mankin's score and the value of gray scale of Safranin O in experiment side was not significantly different from the control side.In high-energy group,the Mankin's score and the value of gray scale of Safranin O in experiment side increased gradually,and was significantly different from the control side.[Conclusion]In the low-energy group,the cartilage returned to the normal level at 4 weeks.In the high-energy group,the cartilage failed to be restored.The degeneration of articular cartilage was very obvious after 4 weeks.

Objective To analyze the effect of reconstruction for the proximal or distal femoral defect by a composite of massive frozen allograft and prosthesis replacement. Methods According to Enneking's classification, malignant bone tumors of the proximal or distal femur were widely resected in 28 cases. Reconstruction of the affected hip or knee joint after major joint removal was done by a composite of allograft and prosthesis. A conventional femoral component with a stem long enough to provide good fixation in the femoral shaft was threaded over a customized allograft. After the assembly had been reduced and checked for size and position, the allograft was cemented to the femoral component, and the composite was in turn cemented into the femoral shaft with PMMA. Results 26 patients were followed up from 6 to 78 months with an average of 41 months. 3 cases died within 18 months following operation; 4 case sustained recurrences within 8 months postoperatively, and underwent re-resection; and the others were alive without diseases. All patients had no dislocation, loosening or breakage of prosthesis. X-rays showed the time of bone healing between allograft and host femur was an average of 7.4 months (range, 5 to 11 months), and the rate of bone healing was 92% (24/26). Absorption was seen around allograft greater trochanter of femur in 9 cases and at femoral condyle in 6 cases. 13 cases with total hip composite replacement had good active extension-flexion degrees of an average of 85?( range, 71? to 124?), and 13 with total knee composite replacement had a rang of motion of 92?(range, 68? to 135?). The postoperative average ISOLS scale score of 26 cases by Enneking's system was 26.2 point (range, 22 to 28). Conclusion The clinical result demonstrated the composite of massive frozen allograft and prosthesis replacement has the advantages of both allograft and prosthesis. Its best indications are that the patients with a major femoral defect from benign or low grade malignant tumor have longer survival expectancy.

[Objective]To evaluate the initial effect of the computer-assisted total knee replacement system.[Method]The 24 computer-navigated knees in our department were involved,and were matched at ratio of 1∶3 by previous cases at sex,age and disease.All cases anteroposterior and lateral projection X-ray films were checked postoperatively.We compared ? and ? angles at anteroposterior films,? and ? angles ant lateral films of all involved cases[Result]Although there was no significant differences existing between two groups,we still observed the obvious reduce risk of malplacement both for femoral and tibial prosthesis,and improvement of mechanical alignment.[Conclusion]By using computer-navigated total knee replacement system during operating,the precise and repeatability could be ensured.