BACKGROUND: The main pathological change of intervertebral disc herniation is that nucleus pulposus protrudes from ruptured annulus fibrosus, thus we can hypothesize that it is possible to prevent disc herniation prior to its protrusion by coagulating it as a whole.OBJECTIVE: To observe the coagulation effects of intervertebral disc nucleus pulposus by alum solution.DESIGN, TIME AND SETTING: A randomized controlled animal experiment was performed between September 2002 and April 2003 at Department of Animal Experiment, Peking University First Hospital, Beijing China.MATERIALS: Twenty-six healthy adult hybrid dogs, 9 for in vitro experiment and 17 for in vivo experiment, weighing 16-21kg, with no restrictions on male and female, were obtained from Department of Animal Experiment, Peking University First Hospital, Beijing, China.METHODS: Twenty canine in vitro intervertebral discs obtained from 5 dogs were randomly divided into 4 groups, with 5 discs in each group, and were put into 2.5%, 5%, 10% alum solutions and 0.9% physiological saline, respectively. Effects of disc coagulation were observed after immersing for 1 day and 10 days, respectively. Another 16 in vitro intervertebral discs obtained from 4 dogs, composed of L2/3, L3/4, L4/5, L5/6, were also injected with the above 4 experimental solutions, 0.15ml, respectively. Sixty-eight in vivo intervertebral discs were obtained from 17 dogs and divided into 4 groups: blank control group, physiological saline group, 10% alum solution+one puncture point group, and 10% alum solution+two puncture points group, 17 discs in each group. Harvesting time: 3 days, 2 weeks, 1 month and 3 months postoperation.MAIN OUTCOME MEASURES: Effects of alum solutions on the coagulation of the intervertebral discs and related histological changes were observed and an alum solution of suitable concentration was preliminarily selected. General observation, light microscopic observation and scanning electron microscopic observation were made of the nucleus pulposuses.RESULTS: In the in vitro and in vivo experiments, it was found that physiological saline did not produce the effect of coagulation on the nucleus pulposus, while immersion in the alum solution induced nucleus pulposus coagulation in the in vitro intervertebral discs. Also, as the concentration of the alum solution increased, the volume of the coagulated nucleus pulposus gradually decreased. After alum solution was injected into the in vitro intervertebral discs, no nucleus pulposus coagulation appeared. When the 10% alum solution was injected into the in vivo intervertebral discs, nucleus pulposus coagulation occurred, with the strongest coagulation effect reached at 1 month postoperation. This was manifested in the agglutination reaction centered around the puncture point. When there were 2 puncture points, 2 coagulated lumps might appear. There was an increase in the mesenchymal component of the coagulated nucleus pulposus. Histochemical and scanning electron microscopic examinations confirmed the proliferation of large numbers of collagen fibers in the mesenchyme.CONCLUSION: Alum can promote nucleus pulposus to coagulate around the injection point. This may be related to the increase of collagens and the fibrosis resulting from stimulation of the nucleus pulposus by alum solution.

[Objective]To investigate the effect of coagulation of intervertebral disc nucleus pulposus(IDNP) by alum.[Method]In vitro,20 canine intervertebral discs(I D) were divided into 4 groups,and immersed into 2.5%,5%,10% alum solution and normal saline respectively.Another 16 I D also randomized into 4 groups and were injected into I D with corresponding solution.In vivo,6 canine ID were grouped into 4:A.blank control;B.one injection of alum;C.two points injection of alum;D.injection of N.S.Experimental dogs were sacrificed and disc samples were taken at 3 days,2 wks,and 1 month post-injection.Gross observation,histological exam by microscopy and scan electron microscopy(SEM) and histochemical test were performed.[Result]NS did not coagulate the IDNP in vivo and in vitro,while in vivo,coagulation was seen around the injection points,two points with two coagulation blocks,and grew with time culminating on one month after injection,but there was no coagulation appeared after alum injection.In vitro,histological study showed aboundant collagenous fibers gathered in coagulation lock representing manifold function of mesenchyme.[Conclusion]The alum can make the IDNP to be coagulated in vivo,the mechanism of coagulation is the collagenous fiber proliferation and fibrosis due to manifold function of mesenchyme.

[Objective]To analyze the failure mechanisms in patients undergoing revision surgery in different time after index total hip arthroplasty(THA).[Method]The clinical records and radiographs of 78 revision hip surgeries between June 1995 and June 2005 loere reviewed.Forty-two cases were total hip arthroplasty and 36 were hemiarthroplasty.Thirty-six patients had revision surgery within 5 years and 42 more than 5 years.[Result]The causes of early revision THA included infection(16 cases),aseptic loosening,acetabular erosion,and mechanical failure.In the late revision THA,aseptic loosening was the most common reason,and the next common reason were acetabular wear and osteolysis around a well-fixed implant.[Conclusion]Infection is a common reason for the early revision.Aseptic loosening is the major cause for the late revision total hip arthroplasty.

[Objective] To evaluate the efficacy and safety of drainage blood autotransfusion after total knee or hip arthroplasty.[Methods]Drainage blood in the first 6 hours postoperation was collected and reinfused using the ContavacTM CBCⅡ system in 30 patients taken total knee or hip arthroplasty.The efficacy was evaluated basing on the amount of the allogenic transfusion,the decreasing of the hemoglobin level and the morphology of the red blood cells in the drainage blood.The safety was evaluated basing on whether the patients had autotransfusion complications including fever,hemolytic reaction,coagulation disorders,pulmonary embolism and systemic infection.[Results]The volumes of total blood drainage,autotransfusion and allogenic transfusion were(946?433)ml,(622?313)ml and(233?348)ml,respectively.The average hemoglobin level of drainage blood was 99.67g/L and no apparente haemolysis happened.However,the hemoglobin level significantly decreased after operation in the peripheral blood.Only one rheumatoid arthritis patient had an abnormal fever during autotransfusion process,no other complication was observed.[Conclusion]Drainage blood in the first 6 hours postoperation is valid blood content.Drainage blood autotransfusion is an effective and safe way to slow down the hemoglobin reduction and reduce allogenic blood transfusion in patients being treated with total knee or hip arthroplasty.

[Objective] To evaluate clinical effect of total hip arthroplasty(THA)with a short-neck and straight stem in patients with osteoarthritis secondary to developmental dysplastic hip with high dislocation.[Methods]From June 2002 to October 2007,total hip arthroplasties with a short-neck and straight stem were performed for 11 patients(12 hips)with osteoarthritis secondary to developmental dysplastic hip with high dislocation.All were females with an average age of 51 years(range from 41 to 68 years).The operations were performed through a posterolateral approach.All the acetabular cups were reconstructed at the original anatomic location,and structural autogenous bone-grafting was performed if the cup was not covered enough by host bone.Short-neck and straight femoral stems were used with cement fixation.During operation,the soft tissue around hip was released extensively.[Results]After surgery,the center of the hip had an average distal translation of 4.5cm(range from 3.8 to 4.8 cm)and the limb length had an average increase of 3.9cm(range from 3.6 to 4.3 cm).All the patients were followed up for a mean time of 36 months(range from 10 to 66 months).All structural autografts united and none of acetabular and femoral components showed loosening.No radiolucent line was observed at the bone-cement and at the implant-cement interface around femoral stem.No patient had sciatic or femoral nerve palsy.The mean Harris score increased from preoperative 41.8 points to postoperative 86.2 points.[Conclusion]THA with a short-neck and straight stem for treatment of osteoarthritis secondary to developmental dysplastic hip with high dislocation avoids femoral shortening osteotomy and greater trochanter osteotomy when the center of hip had a distal translation less than 5cm in preoperative plan,and this choice provides satisfactory results at early-term follow-up.

[Objective] To investigate the radiographic changes of patella after total knee arthroplasty(TKA)with non-resurfaced patellar.[Methods]Fifty-one patients(64 knees)underwent TKA with patellar non-resurfaced.Average age was 68.5 years(range,57~78 years).Average follow-up was 4.8 years(range,2.5~8 years).The radiographic changes of patella,patellar tilt,and patellar lateral shift were evaluated.The functional results of patellofemoral joint were analyzed.[Results]The patellar tilt and lateral shift were improved obviously after surgery.Most patella tracking lied in the middle and there were no obvious degeneration with the time passing.Osteophytes formation and deterioration of patellar tracking were the most common abnormal radiographic changes.There were no obvious relationship between symptoms of patellofemoral joint and patellar degeneration.[Conclusion]Patellar tracking can be improved immediately after non-resurfaced total knee arthroplasty in osteoarthritis patients.There will not be obvious patellar degenerative changes with time passing.

[Objective]To refine operative indications of rotating hinge prostheses and report the medium term results of these implants,and to analyze the reasons for postoperative complications.[Method]From 1999 to 2007,42 Endo-Model(Link) rotating hinge prostheses were used in 34 patients.The cases were all gonarthrosis with severe genu varus,genu valgus or flexion contracture.Bone defect or instability was found in these cases before operation.The mean follow-up was 6.4 years(2.3-10.4 years).[Result]One case of deep infection,and one periprosthetic fracture were noted.And 3 cases of patella subluxation or tilt were detected by postoperative X-ray.All patients had excellent pain relief and restoration of walking capability.The average HSS score improved from 40.5 points to 89 points after surgery.[Conclusion]Besides being used in revision surgery,rotating hinge prostheses are indicated in primary arthroplasties for patients with severe ligament laxity,substantial deformity or bone losses.With appropriate indication selection and accurate operative skill,satisfactory medium term result can be obtained.

Objective To study the causes and symptoms about locking knee of unclear causes and analyze the thrapeutic effects of arthroscopy. Methods Arthroscopy was performed for 47 cases who suffered from locking knee of unclear causes.The main focuses observed were synovial shelf(16 cases),synovial hyperplasia(15 cases),synovial cyst(3 cases),Hoffa disease(4 cases)and patellofemoral malalignment(9 cases).These synovial focuses were resected by arthroscopic shaving.For Hoffa disease,arthroscopic partial resection of the infrapatellar fat pad was done.For patellofemoral malalignment,the procedures consisted of a standard lateral retinacular release and distal realignment of the patella. Results All patients were followed up for 2 months to 3 years on (an average of 1 year).The locking of knee disappeared for all cases and painless of knee for 46 cases.The functional recoveries of Knee joint were mostly excellent. Conclusions The main causes consisted of synovial shelf?hyperplasia?cyst,Hoffa disease and patellofemoral malalignment for locking knee of unclear causes.Arthroscopy is not only an important diagnostic method,but also a significant procedure of treatment and the therapeutic effects are satisfactory.

Objective To investigate the immunologic reactions around prosthesis and the relationship between immunologic reactions and aseptic loosening. Methods Nine specimens of bone- implant interface membranes obtained during revision of loosened total joint replacements were examined in order to investigate the evidence of hypersensitivity. T lymphocytes and it's subgroup (CD 3, CD 4, CD 8),macrophages (CD 68),IL－ 2 receptor (CD 25) and HLA－ DR antigens were demonstrated by immunohistochemistry on tissue sections. The relationship between the changes of T lymphocytes and inflammatory reactions was also evaluated. Results Histological examinations showed granuloma with a plenty of macrophages and foreign body giant cells in all sections of interface membranes. The number of T lymphocytes increased in five of nine cases, and three of them expressed IL－ 2 receptor. The distribution of T lymphocytes and subpopulations was similar in all cases. The increase of T lymphocytes and IL－ 2 receptor expression showed positive correlation with an increase of macrophages and inflammation reactions. Conclusion Hypersensitivity to the prosthetic materials can exist after total joint replacement. Hypersensitivity may be one of the reasons of prosthetic aseptic loosening.

Objective To elucidate the characteristics and treatment options of the primary joint arthroplasty in patients who had a previous history of the joint infection. Methods Eight total joint arthro-plasties in patients who had previous infection of the joint, were analyzed retrospectively from 1992 to 2001. The diagnosis of joint infection was pyogenic infection in six cases, and tuberculous infection in two cases. Total hip arthroplasty was performed in six cases, the average age of which was 38.1 years (24 to 51 years), and the average quiescent period of infection was 22 years ranging from 6 to 30 years. In these six cases, the average age of infection was 16 years (6 to 31 years); the quiescent period of all five pyogenic infections was more than 20 years, and the quiescent period of other one with tuberculous infection was six years. Total knee arthroplasty was performed in two cases. Results The count of WBC, ESR and CRP were examined routinely with normal values before surgery. While, there were no evidences of infection through intraopertive exploration, and bacterial culture of joint fluids and synovial tissue. The duration of follow-up was 2 to 11 years. The affected limbs had significant shortened deformity of 2 to 6 cm before surgery in hip infections. The hip joints had mal-development and flexion-contracture deformity. All of the patients had no active in-fection before arthroplasty. 5 patients with a quiescent period of pyogenic infection of more than 20 years had no recurrence of infection after total hip arthroplasty. One patient with a quiescent period of 6 months had recurrence of the infection after total knee arthroplasty. There were no recurrence of infection in 2 pa-tients who had tuberculous infection. The results were good except aseptic loosening in one total hip arthro-plasty. Conclusion The total joint replacement for patients with previous joint infection is more difficult in performing in one-stage and on younger patients. The good results can be achieved only on condition that the active infection healed completely, and the patients must keep a definite long period of quiescent time after infection.