Objective:To investigate whether endogenous hydrogen sulfide (H2 S)was involved in the pathogenesis of osteoarthritis (OA)and its underlying mechanism,to detect H2 S and its synthases ex-pression in knee cartilage in patients diagnosed with different severity of OA,and to explore the transcrip-tion and expression of gene MMP-13 in chondrocytes treated with IL-1βor H2S.Methods:Synovial fluids of the in-patients with different severity of OA hospitalized in Peking University First Hospital were collected for measurement of H2 S content using methylene blue assay.Articular cartilages of the patients who underwent knee arthroplasty were collected for the cell culture of relatively normal chondrocytes.The chondrocytes were cultured to the P3 generation and H2 S molecular probes were used for detection of endogenous H2 S generation in the chondrocytes.Immunocytochemistry was used to detect the localization of H2 S synthases including cystathionine β-synthase (CBS),cystathionine-γ-lyase (CSE),and mercap-topyruvate sulfurtransferase (MPST)in OA chondrocytes.Western blot was used to quantify the protein expressions of CSE,MPST,and CBS in cartilage tissues of the patients who were diagnosed with OA and underwent knee arthroplasty.The relatively normal human chondrocytes were cultured to passage 3 and then divided into 4 groups for different treatments:(1 )the normal control group,no reagent was added;(2)the IL-1βgroup,5 μg/L of IL-1βwas added;(3)the IL-1β+H2S group,200 μmol/L of NaHS was added 30 min before adding 5 μg/L of IL-1β;(4)the H2 S group,200 μmol/L of NaHS was added. The transcription and expression of gene MMP-13 in chondrocytes of each group were determined with Real-time PCR and Western blot,respectively.And the total NF-κB p65 and phosphorylated NF-κB p65 in chondrocytes were detected with Western blot.Results:The content of H2 S in the synovial fluid of degenerative knee was (14.3 ±3.3)μmol/L.Expressions of endogenous H2 S and its synthases including CBS,CSE and MPST were present in the cytoplasm of chondrocytes.CSE protein expression in Grade 3 (defined by outerbridge grading)cartilage tissues was significantly increased as compared with that of Grade 1 cartilage tissues (1.67 ±0.09 vs.1.26 ±0.11,P<0.05).However,no significant difference of CBS or MPST expression among the different groups was observed.The expression of MMP-13 protein in the IL-1βgroup was significantly higher than that in the normal chondrocytes (1 .87 ±0.67 vs.0.22 ± 0.10,P<0.05 ),and that in the IL-1β+H2 S group was significantly decreased than that in the IL-1βgroup (0.55 ±0.11 vs.1.87 ±0.67,P<0.05),and that in the H2S group had no significant difference compared with that in the normal control group.The transcription of MMP-13 protein in the IL-1βgroup was significantly higher than that in the normal chondrocytes (31.40 ±0.31 vs.1.00 ±0.00,P<0.05), and that in the IL-1β+H2 S group was significantly decreased than that in the IL-1βgroup (24.41 ± 1.28 vs.31.40 ±0.31,P<0.05),and that in the H2S group had no significant difference compared with that in the normal control group.The total NF-κB p65 in the IL-1βgroup was significantly higher than that in the normal chondrocytes (2.13 ±0.08 vs.0.73 ±0.08,P<0.05),and that in the IL-1β+H2S group was significantly decreased than that in the IL-1βgroup (1 .24 ±0.13 vs.2.13 ±0.08,P<0.05 ),and that in the H2 S group had no significant difference compared with that in the normal control group.The phosphorylated NF-κB p65 in IL-1βgroup was significantly higher than that in the normal chondrocytes (1.30 ±0.13 vs.0.19 ±0.04,P<0.05),and that in IL-1β+H2S group was significantly decreased than that in the IL-1βgroup (0.92 ±0.26 vs.1.30 ±0.13,P<0.05),and that in the H2S group had no significant difference compared with that in the normal control group.Conclusion:H2 S affected the cartilage degeneration by partly inhibiting the degradation of extracellular matrix.

Objective To investigate the role of hybrid bone grafting using autograft and freezedried allograft bone in restoration of acetabular bone defect,as well as to evaluate the clinical results of this grafting technique combined with acetabular scaffold in dealing with massive acetabular deficiency.Methods Between April 1999 to December 2007,18 patients (19 hips) underwent acetabular revision by using a mixture of autograft and allogenic freeze-dried cancellous bone particles plus acetabular scaffold.There were 8males and 10 females,aged from 33 to 76 years (average,64.7 years).The acetabular defects were caused by aseptic loosening of primary total hip arthroplasty in 17 patients and osteoarthritis secondary to osteotomy in 1 case of acetabular dysplasia.There were 5 cases of Paprosky Ⅱ B defect,2 Paprosky Ⅱ C defect,6 Paprosky ⅢA defect and 6 Paprosky ⅢB defect.Results All patients were followed up for 3.6 to 12.3 years (average,6.5 years).Harris hip score improved from preoperative 38.7±9.6 to 87.6±7.8 at final follow-up.According to X-rays,bone incorporation evidenced by trabecular bridging of the host-donor interface was found at 3to 6 months postoperatively,and effective bone incorporation was achieved in all cases one year postoperatively.Polyethylene wear occurred in one case.Acetabular component loosening was not found at final follow up.Conclusion Impacted bone grafting using a mixture of autograft and freeze-dried allograft bone can efficiently restore acetabular bone defect.Adding autograft bone to freeze-dried allograft bone is a highly effective way of achieving graft incorporation.Hybrid bone grafting technique with acetabulum scaffold is an attractive option for the treatment of extensive acetabular deficiency.

Objective To evaluate the results and complications of hip arthroplasty performed as a salvage procedure after the failed treatment of intertrochanteric hip fractures in elderly patients. Methods Between 2004 and 2009,10 patients were treated with hip arthroplasty after the failed treatment of intertrochanteric fracture.There were six females and four males,at mean age of 75.7 years ( range,68-84 years).The initial treatment of fractures included dynamic hip screw (DHS) fixation in three cases,dynamic condyle screw (DCS) fixation in one,proximal femur fixation with reconstruction interlocking nail in three and conservative treatment without internal fixation in three.The failed procedures included avascular necrosis in four cases,cephalic implant cutting in three,nonunion in two and malunion associated with osteoarthritis in one.Joint hip replacement was performed except for pre-operative infection.Harris score at follow-up was recorded and prosthesis position was evaluated by imaging. Results Six patients were treated with total hip arthroplasty with a cemented cup (three patients) and an uncemented cup ( three patients) and four with a bipolar hemiarthroplasty.A long-stem implant was used in 5 of the 10 hips.The average duration of follow-up was 4.6 years (2-7 years).The mean duration of surgery was 128 minutes and mean blood loss was 764 ml.The mean Harris hip score increased from 37 preoperatively to 85 postoperatively.The functional results were satisfactory.One 84-year-old patient with the implant intact died 2 years postoperatively from a brain hemorrhage. Conclusions Hip arthroplasty is an effective salvage procedure after the failed treatment of intertrochanteric fractures in elderly patient.Most patients have better pain relief and functional improvements in spite of technical difficulties than primary arthroplasty.In the meantime,attention should be paid to patients with poor bone quality,bone loss,or articular cartilage damage.

ObjectiveTo analyze the influencing factors and clinical results of radial shortening after operation of intra-articular fractures. MethodsA total of 54 patients with intra-articular fractures of the distal radius treated surgically from January 2003 to January 2008 were followed up and divided into radial shortening group ( ＞ 4 mm) and control group ( ＜ 4 mm) by whether radial shortening was more than 4 mm. Fracture types, comminution and defection degree, age, surgical approach and internal fixation method, whether bone implant in operation, post-operative volar tilting angle and ulnar inclination angle, and wrist function score were investigated and compared between the two groups. ResultsThe incidence of radial shortening in post-operation of intra-articular fractures of the distal radius was 30％.Age and whether bone implant in operation were significantly different between the two groups. Type C fractures were more liable to radial shortening than type B fractures. Operation approach and internal fixation method have no significant influence on the radial shortening. Volar tilting angle and ulnar inclination angle were not significantly different between the two groups and the excellent and good rate of function score was lower in the radial shortening group. ConclusionThere is a high incidence of radial shortening after operation for the intra-articular fractures of the distal radius, which affects the clinical results of operation. Therefore, we should pay more attention to the influencing factors and take corresponding precaution methods during operation.

Objective To summarize the perioperative characters of femoral neck fractures in patients aged at over 80 years by analyzing the surgical treatment procedures. Methods A retrospective study was done on data of patients with femoral neck fractures treated surgically from June 2000 and June 2008. There were 25 males and 36 females, at average age of 83.4 years (80-94 years). Of all, there were 53 patients with fresh fractures including six with type Garden Ⅰ or Ⅱ fractures and 47 with type Garden Ⅲ or Ⅳ fractures, eight with old fractures ( all type Garden Ⅳ). Fifty-one patients (84%) were accompanied with preexisted internal medical or neurological diseases. Six patients with type Garden Ⅰ or Ⅱ fractures were treated with cannulated screw fixation (CSF). Among 55 patients with type Garden Ⅲ or Ⅳ fractures inclu-ding 47 fresh fractures and 8 old ones, 53 patients were treated by hip hemiarthroplasty (HHA) but the other two by cemented total hip arthroplasty (THA) because of preexisting hip osteoarthritis. Results The average operation duration and blood loss were 51 minutes and 50 ml in CSF group, 81 minutes and 180 ml in HHA group, 105 minutes and 350 ml in THA group. Fifteen patients (25%) had postoperative com-plications, mostly hypotension, cardiac insufficiency and atrial fibrillation, accounting for 12%. Postoperative hemoglobin was decreased by 11.9%, 17.1% and 18. 1% on average respectively in CSF group, HHA group and THA group, and postoperative albumin decreased by 10.8%, 18. 1% and 20.2% on average respectively in CSF group, HHA group and THA group. There were 17 patients (28%) with hemoglobin below 100 g/L and four (7%) with albumin below 30 g/L after operation. Conclusions The patients aged ≥80 years with femoral neck fractures are usually accompanied with preexisted internal medical or neurological diseases and have high risk in operation. Adequate preoperative preparation and active prevention and treatment of perioperative complications are important for successful operation and good postoperative results.

[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 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 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.