This paper describes briefly the newest progress in the early diagnosis and prediction of the osteonecrosis of the femoral head (ONFH) after femoral head fracture. It is necessary that early operative intervention and aspiration of the intracapsular blood should be done in order to minimize the occurrence of ONFH. It is wise to avoid positioning the hip in extension and internal rotation until surgery. Traction with hip in flexion is recommended. Using the contrast enhanced (Gd DTPA) MRI with T1 fat saturation imaging within 24 hours after injury, the prediction of ONFH will be possible. It is recommended the ONFH should be divided into two types, namely silent and clinical ones.

To sum up the methods which can be used to prevent dislocation after total hip replacement.Recent original articles about the reasons of dislocation and methods which were used to treat or prevent dislocation were extensively reviewed,and retrospective and comprehensive analysis was performed.Dislocation after THA can be reduced by careful assessment of patients,selecting suitable prosthesis,improving the position of prosthesis and avoidance risk movements.Dislocation after THA can be reduced by careful pre-,intra-,and postoperative assessment.

BACKGROUND:Decel ularized scaffolds are special for retaining the tubular structure used for nutrition transport, and providing a similar inner environment for cel growth. OBJECTIVE:To study the preparation of the decel ularized whole liver bioscaffold and to explore its repair outcomes for liver injury. METHODS:Livers from 12 Sprague-Dawley rats were used for preparing the decel ularized whole liver bioscaffold by chemical detergent-enzymes decel ularized technology. Models of liver injury were established in another 24 Sprague-Dawley rats and randomized into two groups:the decel ularized whole liver bioscaffold was implanted into the rat liver lesions in experimental group, and controls were given the injection of normal saline. Thirty days later, the serum levels of alanine aminotransferase and glutamic-oxaloacetic transaminase were detected, and liver tissues were removed for hematoxylin-eosin staining. RESULTS AND CONCLUSION:Hematoxylin-eosin staining showed that extracel ular matrix-like structures existed in the decel ularized bioscaffold;cel components were completely removed from the liver, the col agen fibers in the scaffold arranged regularly and were not dissolved under electron microscope. The serum levels of alanine aminotransferase and glutamic-oxaloacetic transaminase in the experimental group were significantly lower than those in the control group (P<0.05). Hematoxylin-eosin staining showed a large number of blue-stained and dense distributed nuclei, and pink distribution of col agen fibers that had no overt breakages in the control group, while pink and dense structures in the experimental group. These results suggest that the decel ularized whole liver bioscaffold is easy to obtain, and can promote the injured liver repair.

Objective To investigate the natural history of mild adolescent idiopathic scoliosis in a period of 15 years and search for the risk factors of progress as well as to recommend the modification program of school screening for scoliosis. Methods From a group of 204 patients with adolescent idiopathic scoliosis who were detected from school screening for scoliosis among 20 418 school children in Beijing from May 1985 to January 1986, 90 of the patients were reevaluated 15 years later. The follow-up items of the therapeutic history, physical examination and standing spinal X-ray films were carried out. The late data were compared statistically with the original data at the time of school screening. The final results were divided into four groups: 1)Resolved group with a current curve less than 10 degrees; 2)Reduced group with a current curve more than 10 degrees but reducing less than 5 degrees regarding to the original status; 3)Unchanged group with a current curve more than 10 degrees while progressing less than 5 degrees compared to the original data; 4)Progressed group with a current curve was more than 10 degrees and aggravating more than 5 degrees than the original curve. Results Of 204 patients, 111 patients were followed up, and X-ray films were taken in 90. The follow-up results suggested that 29 cases showed resolved(32.2%), 21 cases reduced (23.3%), 30 cases unchanged (33.3%) and 10 cases progressed (11.1%). In 10 cases of progressed group, there were 8 females and 2 males, furthermore, 6 patients were found with the cobbs angle of curve between 10 and 19 degrees and 4 patient with the cobbs angle of curve more than 20 degrees when school screening. The curve pattern of the 10 progressed patients consisted of double thoracic curves in 2, double thoracic and lumbar curves in 2, right thoracic curve in 3, thoraco-lumbar curve in 2 and lumbar curve in 1. Conclusion Most of cases with less than 20 degrees curve are of no progress. The high risks of progress are as followed: curve more than 20 degrees, female, double thoracic curve, double thoracolumbar curve, right thoracic scoliosis and top vertebral rotation more than grade Ⅱ. The school screening for scoliosis should be carried out by school medical team who were trained by orthopaedists. The specialists should reexamine the suspected children and monitor the patients with high risk of progress.

BACKGROUND: As the result of estrogen shortage due to ovariectomy,osteoporosis occursin the general and local bones, displaying bone loss and changes in bone microstructure and growth factor mRNA expression,which definitely has an important effect on fracture healing. OBJECTIVE: To probe into the effect of estrogen on bone microstructure and bone morphogenetic protein-4 mRNA expression and location during fracture healing. DESIGN: Randomized controlled study. SETTING:Laboratory of the Department of Molecular Biology of Yunnan University. MATERIALS: This study was conducted at the laboratory of Molecular Biology Department of Yunnan University between July 1999 and July 2002. We recruited 96 healthy female SD rats of 2 months old and with the mean body mass of 160 to 200 g. METHODS:①Of the 96 rats that received intraperitoneal anesthesia, 48rats were subjected to bilateral ovariectomy(osteoporotic group), and the other 48 rats received sham operation (control group). One month later, bilateral tibia fracture at the middle segment was artificially made on all rats under anesthesia, and no treatment was given so as to prepare fracture healing model. Then rats of both groups were put to death for collecting callus and the surrounding parenchyma at postoperative 1, 3, 5, 7, 14, 28,56 and 112 days, with 6 rats in each time point. ② The tibia bone microstructure was observed under electron microscope. ③ The mRNA expression of bone morphogenetic protein-4 at callus and the surrounding paranchyma was detected by RT-PCR method; no probe in hybrid fluid was used as negative controls. Six in situ hybridization slices with positive expression were selected from both groups at postoperative 1 and 3 days time points, and 3 visual fields were randomly selected from each slice for observing the positive granules under 25 times field lens. MAIN OUTCOME MEASURES: ①The tibia bone microstructure;② bone morphogenetic protein-4 mRNA expression at callus and the surrounding parenchyma. RESULTS: All the 96 rats entered the final results analysis. ① Observation of the tibia bone microstructure: at 28 days after tibia fracture, osseous callus and ostein fibers were found arranged densely in control group. Osteocytes, small with fewer cytoplasts, were observed in osseous lacuna, but osteoclasts were found surrounding small-sized bone trabecula. In osteoporotic group, fibrous callus and collagenous fibers in bone matrix were arranged loosely, lots of big osteoblasts could be observed with osteocytes easily seen. ② Bone morphogenetic protein-4 mRNA expression at callus and the surrounding parenchyma: it was less expressed in control group than in osteoporotic group at postoperative 1 to 3 days (23.714 3±5.056 8,21.714 3±5.023 8 vs 51.285 7±8.138 7,49.571 4±9.071 1, P ＜ 0.01) and the expression was mainly observed in parenchyma surrounding the fracture where callus was formed. CONCLUSION: Bone morphogenetic protein-4 mRNA expression is increased in osteoporotic group and is mainly observed in parenchyma surrounding the fracture, displaying a manner of regional expression. However,the formation and quality of callus matrix during fracture are obviously poorer than in control group.

Objective To determine the applicability of locally continuo u s application of alendronate for the prevention of prosthesis aseptic loosening. Methods Using the method of in vitro cell culture to detect the influence of a lendronate with different concentrations(1?10－11mol/L,1?10－9mol/L,1?10－7mo l/L,1?10－6mol/L,1?10－5mol/L) on the proliferation, secretion and osteogenesi s of human osteoblasts as well as the effect of the motility, respiration, phago cytosis and bactericidal ability. Results Higher concentration of alendronate(1 ?10－6mol/L,1?10－5mol/L) improved local antiinfection ability, but inhibited osteogenesis (1?10－5mol/L). Lower concentration(1?10－11mol/L,1?10－9mol/L,1 ?10－7mol/L) inhibited the bactericidal effect of neutrophils, but stimulated o steogenesis(1?10－11mol/L,1?10－9mol/L). Conclusion Locally continuously usin g alendronate around prosthesis to prevent and treat aseptic loosening must be h andled with discretion. Its concentration should not be below 1?10－6mol/L in the early period after arthroplasty operation, but the concentration should be 1?10－11mol/L or 1?10－9mol/L in the late period.

Objective To explore the risk factors of collapse of osteonecro si s of the femoral head (ONFH) with a retrospective study, and put forward a treat ment protocol according to this study results. Methods From October 1993 to Apri l 2000, 40 cases (56 hips) were followed-up. The term of follow-up ranged from 1 2 to 68 months (average 29.2 months). The age of patients was from 16 to 60 year s old (average 36.8 years old). Preoperatively, the AP and frog view X-ray film, coronal and sagittal MRI were taken. The staging of ONFH proposed by ARCO was a dopted. Clinically the Harris score was used to assess the clinical outcome. The patients were divided into three groups: 1) Non-operative: 10 cases (14 hips), stage Ⅰin 7 hips(ⅠA 4,ⅠC 3),stageⅡin 7 hips (ⅡA 1,ⅡB 3,ⅡC 3); 2) Core dec ompression with vascularized iliac bone graft (VICBG): 18 cases (24 hips ), stag eⅠin 6 hips (ⅠB 4,ⅠC 2), stageⅡin 16 hips (ⅡA 4,ⅡB 8,ⅡC 4), stageⅢ in 2 hips (ⅢA); 3) Transtrochanteric rotational osteotomy(TRO): 12 cases (18 hips), stageⅡin 1 hip (ⅡC), stageⅢ in 17 hips (ⅢA 8, ⅢB 7,ⅢC 2). Harris score was 46 to 82 (mean 62.9). Results Collapse of the femoral head occurred in 9 hips a mong the 14 hips in the nonoperative group, in 10 hips among the 24 hips in the VICBG group. In TRO group, further deterioration was prevented in all but one hi p. Whether theres surgical intervention or not, no collapse occurred in both s tageⅠA and ⅡA, collapse occurred in both stage ⅠB and ⅡB was 7 hips among 15 hips (46.7%), 13 hips progressed into collapse of the femoral head with ⅠC and ⅡC (100%). The Harris score was 47 to 93(mean 77.4) postoperatively. Conclusio n With MR imaging, it is possible to predict the possibility of collapse of ONFH . The lower risk is below 30 percent of necrotic area, the higher risk is 30 to 60 percent of necrotic area, and the higherest risk is beyond 60 percent of necr otic area. The best results can be obtained if selection of treatment individual ly according to ARCO stage, patient age and necrotic extent.

[Objective]To explore the causes and treatments of recurrent dislocation after total hip replacement.[Method]From July 1999 to January 2007,there were 47 cases of dislocation after total hip replacement.Thirteen cases were recurrent.CT and serial X-rays were taken to observe the position of prosthesis.The strength of their hip abductor was also tested.Stability test was used to value the stability of hip.Closed reduction,modular adjustments and revision were adopted according to patients,willingness,prosthesis and stability.[Result]All of the 13 patients had malposition.Eleven cases were tested with instability.Five cases were successfully treated by closed reduction.Despite dislocation reoccurred 1～2 times every year in 3 patients treated by closed reduction,patients felt satisfactory.In the 4 cases with modular revision procedure,2 cases changed the neck length,1 case used elevated liner and larger neck length,1 cases treated by using larger offset and adjusting abnormal liner.Another one treated by revision.[Conclusion]Malposition is the major causes of recurrent dislocation.The prosthesis test whowed instability.The treatments of recurrent dislocation after THA should use different ways according to the causes of dislocation,stability of prosthesis and the willingness of patients.

[Objective]To investigate the role of CT measurement of distal femur rotational angle in total knee arthroplasty. [Methods]From April 1998 to April 2005,eighty-four patients(106 knees)underwent total knee arthroplasty(TKA),including 48 rheumatoid arthritis(RA)knees,and 67 osteoarthritis(OA) knees and one case of pigmented villonodullar synovitis.All the patients in the study were measured by computed tomographic scanning (CT). The examination was positioned in supination,or neutral position of the lower limbs.The distal femur was micro-scanned by 3 mm width.On the screen one line was made between the two hypocondyles of the femur,and another line was made between the medial epicondyle fossa and the external epicondyl fossa of the femur.The angles of the two lines were measured.The bone resection of femur antero-posterior condyle was performed according to the preoperatively measured angles.Six months after operation,the range-of-motion of knee was examined. A control group(49 knees in 40 patients) to the conventional TKA of the 3 degree external rotation bone resection was comparatively studied. All the operations were made by the same surgeon,and all the prostheseswere the type of PFC ( Press Fit Condyle).[Results]The results indicated that the rotational angles of the distal femur were above 3 degrees in north Chinece population with the male of 5.1 degrees (SD 1.7) and female of 5.8 degrees(SD1.5).[Conclusion]The rotational angler of the distal femur are above 3 degrees in north Chinece population. If the bone resection of femur was performed according to the preoperatively measured angles,the postoperative result is more favourable than the conventional bone resection according to the 3 degree external rotation.

Objective To explore the indication, to describe the key of operative technique in detail and to summarize the early results in mini-incision and minimally invasive surgery (MIS) total hip arthroplasty (THA) for hip disorders. Methods From Mar. 2003 to Mar. 2005, 43 patients (49 hips) were performed with MIS THA. The mean age of patients was 53.2 years ranging from 22 to 79 years. There were 22 males and 21 females. The average body mass index (BMI) was 23.4 ranging from 17.1 to 30.2. Using the modified postero-lateral approach, MIS THA was performed with cementless prostheses. For comparison, 35 patients (43 hips) were performed with standard THA at the same period. The age and BMI of patients in both groups were similar, but the pattern of disorders was different. The comparative items included preoperative bleeding, operative time, incisional length, postoperative functional recovery, and prosthetic position. Results 31 patients (MIS THA) and 25 patients (standard THA) were followed from 6 to 24 months (mean 13.1 months). No complications occurred in MIS THA. Dislocation appeared in one patient with standard THA at the two days after operation. The length of incision was 9.3 cm (range, 8.7 to 10.5 cm) in MIS group and 16.8 cm (range, 14 to 20 cm) in standard THA group. The difference was significant statistically (P