Objective To study the effect of articular step-off on knee joint contact pressures in fractures of the medial tibial plateau. Methods Eight specimens of embalmed adult knee joint were used to establish models of articular step-off of the medial tibial plateau by 0,1,2,3 mm respectively (Schatzker Ⅳ fracture) .The technique of pressure sensitive film was used to measure the contact pressures on the weight-bearing area of the knee joint in the 3 models. Results When the step-offs of medial tibial plateau were 0,1,2,3 mm,the average contact pressures on the lateral compartment were respectively 3.34 ± 0.06 MPa,3.48 ± 0.06 MPa,4.19 ± 0.05 MPa,4.19 ± 0.04 MPa,while the average contact pressures on the medial coMPartment were 4.04±0.17 MPa,4.57±0.20 MPa,5.64±0.20 MPa,5.64±0.19 MPa.When the step-off of medial tibial plateau was 2 mm,the average contact pressures on the medial and lateral plateaus increased by 39.6％ and 25.4％ compared with the 0 mm step-off,with statistically significant differences (P ＜0.05). Conclusions If the step-off of the medial tibial plateau reaches ≥ 2mm,open reduction and internal fixation should be indicated to prevent secondary traumatic arthritis.When the step-off of the medial tibial plateau is ＜ 2 mm,conservative treatment can be a proper choice.

BACKGROUND:Elderly patients with femoral neck fractures have poor regulatory mechanism, accompanied by a variety of comorbidities and complications, so the treatment and rehabilitation of perioperative femoral neck fracture is very important.
OBJECTIVE:To review the prosthesis selection and complication treatment in perioperative femoral neck fracture in elderly patients.
METHODS:A computer-based research was conducted in PubMed database and CNKI database for the articles published since 2000, the key words were“elderly, femoral neck fracture, perioperative, treatment and rehabilitation, hip fracture”in Chinese and English. The clinical researches were selected. The subjects were the femoral neck fracture patients with the age over 65 years. The review literatures and the literatures with smal cases and old were eliminated, and final y 20 literatures were included for analysis.
RESULTS AND CONCLUSION:Due to the osteoporosis of the elderly patients, the internal fixation often failed. For the Garden Ⅲ and Ⅳ femoral neck fracture patients with the age over 65 years, as long as there is no clear contraindication for surgery, the hip replacement is often used for the treatment. The tolerance of the patients should be accurately evaluated before replacement, and the blood pressure, blood glucose and various medical complications should be control ed;the rehabilitation training after replacement is also essential. The common complications in elderly patients after replacement include stress ulcer, deep venous thrombosis, neuropsychiatric symptoms, urinary tract infections and the surgical infection.

Objective To explore a new surgical procedure of open reduction and internal fixation for intraarticular fractures of calcaneus and its clinic outcome. Methods Between August 2004 and August 2005, 54 feet in 44 patients with calcaneal fracture were treated in our department. Based on the results of X-ray and coronal CT scan before and after treatment, small incision (2-3 cm) at lateral sides of calcaneus, self-made calcaneal anatomical plate and stud bolt were used. According to Sanders classification system, there were 12 cases of type Ⅱ, 32 cases of type Ⅲand 10 cases of type Ⅳ. Results The internal fixation with the calcaneal anatomical plate almost restored the height, length, width, Blher's and Gissane's angles of the calcaneus for the 44 patients. No infection of incision happened. The results were evaluated using Maryland Foot Score. 54 fractures were followed up for 2 to 12 months (averaging 8.3 months) after treatment. Excellent results were noted in 26 fractures,good in 24,fair in 4, and the excellent and good rates were 92.6%. Conclusion The open-reduction and internal fixation with self-made calcaneal anatomical plate and stud bolt is one of the best ways for treatment of fracture of calcaneus.

0.05).There was statistic significance in blood lose with more lose in initial conservative group(P

[Objective]To study the imageologic characteristic of pelvic arterial anastomosis and the method of ultraselection arterial embolism for pelvic fracture with hemorrhage.[Method]From 1999.1-2005.6,60 patients were undergone pelvic arteriography.The patient ages ranged from 21 to 52 years of age(mean,34.5),and 42 were male,18 were female.Measure the types and number of pelvic arterial anastomosis.[Result]The types and number of pelvic arterial anastomosis were observed by pelvic arteriography as follows: the lumbar artery with iliolumbal artery 100%;the iliolumbal artery with deep iliac circumflex artery 83.33%;the obturator artery with inferior epigastric artery(or external iliac artery) 36.67%;the lateral sacral artery with coccygeal artery 100%;the inferior gluteal artery with internal pudendal artery 26.67%;the inferior gluteal artery with deep femoral artery 56.67%;the superior gluteal artery with inferior gluteal artery 61.67%.[Conclusion]For pelvic fracture whith hemorrahge,the best treatment of the pelvic arterial disruption is embolization of injured arteries and their anastomosis.

Objective To study the risk factors,methods of etiologic diagnosis and treatment of disunion of fracture due to delayed infection after the internal fixation. Methods The clinical data including bacterial tests, clinical manifestation and the administration of antibiotics , of 24 cases of disunion of fracture due to delayed infec-tion after the internal fixation were retrospectively analyzed. Results 22 strains of pathogenic bacteria were distin-guished with a detection rate of 91.67% in the 24 cases. 16 strains of these bacteria were gram-positive,and 6 gram-negative. The gram-positive ones were all sensitive to vancomycin and teicoplanin. The gram-negative ones were all sensitive to imipenem and meropenem. It was common for patients to take antibiotic after operation. Conclusion More infection is caused by gram-positive bacteria than by gram-negative ones. Antibiotic therapy based on the bacte-rial test is reasonable and necessary besides surgeries.

Objective To investigate the clinical application of epinephrine hydrochloride in the prevention of bone cement implantation syndrome in the cemented hip replacement. Methods The clinical data of 48 patients treated with cemented hip replacement from July 2008 to April 2009 were retrospectively analyzed. All the patients were divided into control group and intervention group. The bone marrow cavities of 24 patients in the control group were not pretreated with saline epinephrine hydrochloride before implantation of bone cement; the bone marrow cavities of 24 patients in the intervention group were pretreated with saline epinephrine hydrochloride before implantation of bone cement. Systolic blood pressure (SBP), diastolic blood pressure (DBP), the mean arterial pressure (MAP), heart rate (HR)and pulse oxygen saturation ( SPO2 ) were compared between the two groups before bone cement implantation and 1,2, 3, 4, 5, 6, 7, 8, 9, 10 minutes after bone cement implantation. The data were analyzed with variance analysis and Q test. Results (1) In the control group: the blood pressure was decreased in control group one minute after bone cement implantation and a significant decrease of the blood pressure was observed at 2-6 minutes after the implantation ( P ＜ 0. 01 ). The blood pressure was increased seven minutes after the implantation, with the most significant increase of DBP ( P ＜ 0.05 ).The blood pressure recovered to normal 10 minutes later. The SPO2 was decreased significantly ( P ＜0.05 ) but no significant change was observed in HR ( P ＞ 0.05). (2) In the intervention group: the bone marrow cavity was pretreated with saline epinephrine hydrochloride before implantation of bone cement.ity. No significant difference was found in SBP, DBP, MAP, HR and SPO2 at different time points before and after bone cement implantation (P ＞0.05 ). Significant decrease of blood pressure and SPO2 was observed in control group and a significant hemodynamic change was detected at 2-6 minutes after the bone cement implantation. In the intervention group, no hemodynamic change was found in all the patients except that one patient was found with decrease of blood pressure and another one with the occasional premature ventricular contractions. Conclusion Pretreatment of bone marrow cavity with saline epinephrine hydrochloride can effectively prevent bone cement implantation syndrome.

Objective To evaluate the effect of different degrees of pubic symphysis diastasis on the stress distribution of posterior pelvic ring. Methods Eight embalmed pelvis and articulated proximal 1/3 of the femurs were harvested for this study. The samples were positioned as both legs standing straight and loaded to 600 N on the on the CSS-44020 biomechanical machine. The strain gages were adhered to 38 sites distributed symmetrically on the two sides of sacroiliac joint, anterior sacrum and posterior ilium. The strain gages were connected to WS3811 digital strainometer to record strain changes of the intact pelvic ring and at 1,2, 2.5 cm of pubic symphysis diastasis. Results Elastic changes occurred in the cortical bone of the pelvis under 600 N load. The symmetrical sites had similar strain changes without significant difference in the intact pelvic ring and at 1,2, 2.5 cm of pubic symphysis diastasis ( P ＞0.05 ). The sites with more strain changes were distributed on the iliofemoral arch in the intact pelvis.The strain changes were increased significantly frona the posterolateral sites to the iliofemoral arch. But the strain changes on the iliofemoral arch were decreased significantly during pubic symphysis diastasis.Conclusion The conduction of vertical load runs along the sacrofemoral arch in the intact pelvic ring and redistributes posterolaterally during pubic symphysis diastasis.

Objective To observe the curative effect of internal compression in the treatment of intra-articular fracture of the calcaneus by anatomical plate with compression bolt through the sinus tarsi approach.Methods Forty-nine patients with 62 calcaneal fractures treated with anatomical plate with compression bolt through sinus tarsi approach from September 2006 to May 2009 were enrolled in the study.According to Sanders classification,there were 39 patients with type Ⅱ fractures,20 with type Ⅲ fractures and three with type Ⅳ fractures.The axial and lateral view X-ray radiographs and the axial,semi-coronal and sagittal computed tomography (CT) images of the heel were taken before and after operation.The reduction of posterior articular surface of calcaneus and calcaneal shape was observed and the width,height,length,B(o)hler' s angle and Gissan' s angle were measured on the radiographs,respectively.Partial weight bearing was allowed 12 weeks after operation and full weight beating was allowed 16 weeks after operation.The anatomical plates were removed 8-15 months after operation.The Maryland hindfoot score system was applied to evaluate the function of the hindfoot postoperatively.Results All the patients were followed up for 7.5-23 months (average 10.6 months),which showed no wound infection.The reduction of the posterior facet was nearly anatomical (less than 3 mm articular displacement) in all patients and the shape of the calcaneus was satisfactory.The width,height,length,B(o)hler' s angle and Gissan' s angle were improved significantly in all patients (P ＜0.01 ).According to Maryland hindfoot scoring system,29 feet scored 90-100 points (excellent),18 feet scored 80-90 points (good),10 feet scored 70-80 points (moderate) and 5 feet scored 60-70 points (poor).A total of 40 patients (82％) were able to return to their original occupations at mean 9.1 months ( 6.0-12.9 months ) after the injury.Conclusion The anatomical plate with compression bolt internal fixation through sinus tarsi approach is an ideal method for the treatment of displaced intra-articular calcaneus fracture.

Objective To observe the results of treatment by open reduction and humeral head replacement for proximal humeral fracture-dislocation. Methods According to Neers classification, the cases included two-part proximal humeral fracture-dislocation 15 cases, three-part proximal humeral fracture-dislocation 29 cases, and four-part proximal humeral fracture-dislocation 21 cases. Fifty-four patients received T shaped steel plate and 11 patients received humeral head replacement. Early rehabilitation was started postoperatively. Results Fifty-four patients who received T shaped steel plate were followed up from 1 to 5 years (in average of 2.5 years), final results of all the patients were evaluated according to the HUANG Gong-yi′s criterion. The rate of excellent or good in patients of two-part fracture-dislocation were 100%, three-part fracture-dislocation was 79%, humeral head necrosis was 25%, four-part fracture-dislocation was 60%, and humeral head necrosis was 53%. Eleven patients who received humeral head replacement were followed up from 6 months to 5 years (in average of 1.5 years). According to SSMH of UCLA, the average score was 25.6. Score was above 27 in 1 case, 24~27 in 8 cases, 18~ 23 in 2 cases, less than 18 in 0. These cases were with an excellence rate of 82%. Average score was 9.0 in pain, 8.2 in function and 7.5 in muscle power. Conclusions T shaped steel plate to treat the two-part proximal humeral fracture-dislocation is effective in the functional recovery of the shoulder joint, but the rate of satisfaction as well as the necrosis in the three-part and four-part is poor. Satisfactory results can be obtained in humeral head replacement for the treatment of proximal humeral fractures especially for the treatment of three and four-part fracture-dislocation.