[Objective]To investigate the injury characteristics and treatment of the Hoffa facture associated with extensor mechanism injury.[Method]Four patients with Hoffa facture associated with extensor mechanism injury treated in author's hospital in recent 6 years were enrolled in this study.All the patients were multiple-injured,and associated with the ipsilateral limb fracture and retinacular and capsule laceration.The site of the extensor mechanism injury included 1 distal patellar tendon disruption,2 proximal patellar tendon disruption,and 1 distal quadriceps tendon disruption.No cruciate ligament injury was found in 3 ipsilateral bicondylar fractures.One unicondylar fracture was associated with anterior and posterior cruciate ligament and medial collateral ligament injury simultaneously.Emergency operation was performed along with the debridement in the three open fractures.In another patient with closed fracture,operation was performed one week after injury.Fractures were reduced and fixed with lag screws.Extensor apparatus were repaired and strengthened with a tension band wire through both patella and tibia.Ipsilateral limb fractures were reduced and internal fixed with hardware simultaneously. The knees were immobilized in extension with cast after operation,and flexion exercise was commenced four to six weeks later.[Result]Four patients wounds reached the first rate healing.There was no infection and necrosis of skin.All patients were followed-up for six months to three years.All 7 condyles of the 4 patients reached bone union.Healing time was about six to twelve weeks.According to Letenneur’s functional assessment system,excellent and good results were in 1 cases,fine in 3 cases.[Conclusion]Hoffa facture associated with extensor mechanism injury are usually accompanied with injuries in other part of the body.In open fracture,emergency operation is mandatory,and fracture reduction and internal fixation and extensor apparatus repair should be performed along with debridement.Tension band wire may strengthen the stability of the extensor mechanism and facilitated early mobilization.

[Objective]To explore the surgical technique for the treatment of different acetabular fractures.[Method]Consecutive 126 cases with displaced acetabular fractures were undergone an open reduction and internal fixation at our hospital from January 1995 to March 2006.Of them,there were 61 cases with simple type of fractures,65 cases with complicated type,and 14 cases with old fracture,112 with fresh fracture.The following precedures were taken according to the fracture type,namely,free fracture fragments in the hip joint were first dealed with,compressed or reversed subcartilage fracture blocks in the weight-bearing area of the joint should be reduced.By assistanee with some particular acetabular surgical instruments,the rotated or anterior/posterior(medial/lateral) displacement of the fracture was first reduced,then apart displacement of fracture was finally repositioned,and then fixed with reconstructed plate.[Result]No perioperative deaths occurred.After operation,anatomic reduction was achieved in 78 cases,good reduction in 42,incomplete reduction in 6.At a follow-up of 1 to 12 years,a excellent and good result was attained in 90.47% of the patients according to the American Academy of Orthopedic Surgeons(AAOS) score.[Conclusion]The different method of open reduction should be taken for different fracture of the acetabulum.The exact methods of the reduction are determined by the fracture type and its displacement direction as well as the operative approach.

[Objective]To provide Chinese morphological data for anterior C1、2 transarticular screw fixation.[Method]With a digital vernier and a goniometer made in China,the anatomic parameters related to anterior C1、2 transarticular screw fixation were measured from 50 pairs of dried Chinese adult human C1 and C2 vertebrae.[Result]In the anterior transarticular screw fixation,the lateral angulation of the screw tract to the sagittal plane ranged from(10.8?2.10)? to(25.13?3.12)?,the posterior anguation to the coronal plane from(8.85?2.12)? to(26.96?3.09)?,the screw tract length was from(17.48?2.1) mm to(25.4?2.59)mm,the distance from medial part of C2 foramen to the middle of C2 body was(14.12?1.28)mm.[Conclusion]It is optimal for the anterior C1、2 transarticular screw fixation to place the anterior C1、2 transarticular screw with the length of 17 mm to 25 mm in lateral angulation ranged from 10? to 25? and the posterior angulation ranged from 9? to 27?.During the procedure,the dissecting distance from the middle of C2 to lateral should not exceed 14 mm.

[Objective]To explore the techniques and effect of atlantoaxial instability with posterior transarticular screw fixation.[Method]A prospective clinical analysis was performed for the results of the modified posterior C1、2 transarticular screw fixation,in which the middle site of lower margin in the axial inferior articular process was used as the screw entry point in the procedure.Twenty cases of atlantoaxial instability underwent the modified C1、2 stabilization with morselized autograft from September 2001 to September 2006.There were 15 males and 5 females,averaged 32.2 years(range 17 to 49 years).Of them,4 cases suffered from fresh injuries,14 from old trauma,1 from congenital deformity,and 1 from intraspinal tumor.Postoperative indexes including the reduction extent of vertebral body,internal fixation,bone fusion,clinical symptoms and their complication were observed periodically.[Result]Bilateral screw fixation was used alone in 17 cases,with Gallie interspinous wiring for added stability in 3.Anatomical reduction of the atlantoaxial joints was achieved in19 cases,while rotational dislocation was restored to a great extent in 1.Fixation of all the internal devices was very well in the group.All cases were followed up from 16 to 64 months(21 months on average).C1、2 bony fusion was obtained in postoperative 2 to 3 months,clinical symptoms relieved and no complications occurred.[Conclusion]The modified posterior transarticular screw fixation using new screw entry site is recommended as an effective treatment for C1、2 instability due to its simple procedure and satisfying curative effect.

[Objective]To study the screw trajectory in the posterior atalanto-axial transarticular screw fixation.[Methods](1)The anatomical parameters related to the screw fixation were measured on 30 paired dry atlantoaxial specimens;(2)The X ray and CT scan were taken after C1、2 was fixed by posterior transarticular screws on 6 cadavers.These iterms were used to explore the anatomical relation of the vertebral artery and the screw trajectory in the posterior C1、2 fixation.[Results]The depth of the vertebral artery groove on the inferior surface of the superior facet of the axial was(5.86 1.45)mm;the vertebral artery groove extented the superior facet up to its medial third in 15 sides,up to the middle third and its lateral third respective in 35 and 9 sides,and the ideal screw trajectory medial angle of these specimens were(26.4?3.44)?,(16.1?2.44)?,(15.1?2.24)? respectively。The shortest distance between the vertebral artery and the screw trajectory lied in the topmost point of the vertebral artery groove of the axial on CT images,and the interval was(2.75～5.78)mm.[Conclusion]The position of vertebral artery groove of the axial is the key to decide the angle of the screw trajectory.The shortest interval between screw trajectory and vertebral artery,safe for posterior atalanto-axial transarticular screw fixation,locates on the inferior surface of the superior facet of the axial.

0.05). JOA scores of group A is higher than those of group B on 1, 2, 4 weeks postoperatively and the difference is of statistical significance (P

[Objective]To study the surgical technique for the treatment of acetabular fractures.[Method]Retrospective analysis on consecutive acetabular fractures operatively treated at our hospital from January 1995 to March 2005 was made to find out the correlation factors influenced on the operative approaches.[Result]A total of 107 cases had surgery for an acetabular fracture in the meamtime.Of them,44 were exposed through a Kocher-Langenbeck approach,5 through an extended iliofemoral route,30 through an ilioinguinal or an anterior extensile approach,and 28 through a combined anterior and posterior incisions.After operation,anatomic reduction was obtained in 66 cases,good reduction in 36,incomplete reduction in 5.According to AAOS score,the satisfactory rate was 89.72% after following-up 1 to 11 years.[Conclusion]To determine reasonable surgical exposure of an acetabular fracture,the key factors are fracture type and its displacement direction,and the important reference factors include associated injuries with the fracture,operative time and complications related to different operative routes.

Objective To study method and timing of internal fixation for long bone fractures in polytraumatized patients with fat embolism syndrome (FES). Methods Twenty-eight cases of polytraumatized patients with FES received internal fixation for their long bone fractures in our hospital from January 1990 to August 2004. The method and timing of internal fixation were analyzed retrospectively. The long bone fractures in 27 cases were treated 5 to 7 days after their clinic FES symptoms disappeared, while one fracture was treated five days after the FES symptoms were relieved and the vital signs became stable. Eleven cases of long bone fracture were treated with open fixation by unreamed or slightly reamed intramedullary nailing while 27 cases were fixated with plate internally. Results Of the 27 patients who received open reduction and internal fixation for their fractures 5 to 7 days after disappearance of FES symptoms, 22 cases experienced no postoperative complications but fever and quickened pulse reoccurred in five cases after the first osteosynthesis. However, FES-like symptoms reoccurred in the one case who received the first operation when FES did not disappear. Conclusions Internal fixation by plate and intramedullary nailing without reaming are safe for polytraumatized patients with FES and long bone fractures. Proper timing of the first surgery for this kind of patient should be 5 to 7 days after the disappearance of FES.

Objective To analyze clinical outcome of anterior atlantoaxial transarticular screw fixation in treatment of atlantoaxial instability.Methods Thirty-two patients with atlantoaxial instability treated between March 2004 and June 2009 were enrolled in the study.The patients consisted of 21 males and 11 females,at age of 22-64 years (mean 49 years).Atlantoaxial instability was attributed to old odontoid fracture in 10 patients,free odontoid malformation in 16,transverse ligament rupture in two,and rheumatoid arthritis in four.Anterior atlantoaxial transarticular screw fixation under monitoring of cortical somatosensory evoked potential (CSEP) was performed for all patients.Operation time,intraoperative blood loss,and complications were recorded.Japanese Orthopedic Association (JOA) scoring system was used to evaluate neurologic function preoperatively and at one year postoperatively.Results Operation lasted for average 98 minutes and intraoperative blood loss averaged 110 ml.Injuries on esophagus,nerve and vertebral arteries as well as leakage of cerebrospinal fluid were not observed in operation.All patients received a follow-up of 12-31 months.JOA score was increased from preoperative 9.8 points to 15.8 points at one year postoperatively,with improvement rate of 83％.Bone fusion and satisfactory internal fgxation were achieved in all patients.Hypoglossal nerve injury symptom was found in two patients postoperatively and was recovered two months later.Conclusion Anterior atlantoaxial transarticular screw fixation is an effective treatment for atlantoaxial instability.

BACKGROUND: Repair of segmental bone defects is one of the difficult problems in orthopaedics. Although the therapeutic effect on bone autograft is the best, the source is limited and there is lack of suitable substitutive materials for autologous bone.OBJECTIVE: To probe into the therapeutic effects of surface-decalcified bone matrix gelation(SDBMG) and the substitutive possibility of autologous bone on repair of segmental bone defects.DESIGN: The research was designed as completely randomized controlled experiment. The clinical research was designed as pre- and post-controlled study on the basis of diagnosis.SEETING: Department of Orthopaedics, Wuhan General Hospital of Guangzhou Military Area Command.MATERLALS and PARTICIPANTS: The experiment was accomplished in Laboratory of Wuhan General Hospital of Guangzhou Military Area Command, and Testing Center of Wuhan University of Technology. Thirty-two local healthy adult male rabbits were employed as the materials in the experiment, 2.5 kg in body mass, bought from Hubei Academy of Medical Sciences. The clinical subjects were 31 patients(male 25 and female 6, a meanage of 9 years old) with segmental bone defects hospitalized in the Department of Orthopaedics, Wuhan General Hospital of Guangzhou Military Area Command during January 1991 to May 2001.METHODS: The 32 rabbits were randomized into group A and group B. The bilateral radial bones were prepared into 1-cm bone defect in both groups. In both groups, SDBMG was grafted on the left side; in Group A, wholly-decalcffied bone matrix gelatin(WDBMG) was grafted on the right side;and in Group B, the autologous bone was grafted on the right side. Human SDBMG was provided to treat 31 cases of segmental bone defects.MAIN OUTCOME MEASURES: ① Regular X-ray and histological examinations after operation in animals(Group A) and biomechanical deterruination (Group B ). ② Regular X-ray examinations after operation.RESULTS: SDBMG induced osteogenesis process "gradually" from exterior to interior. The bone repair with SDBMG was similar to that with autologous bone, and there was no significant difference in compressive strength compared with autologous bone. After clinical follow-up, except failure in 1 case due to improper selection of indication, the other 30 cases were all cured.CONCLUSION: SDBMG provides satisfactory osteogenesis and reliable mechanical property. It can be taken as the suitable substitutive material for autologons bone in the repair of segmental bone defects. But it is cautious for the application of SDBMG to infective bone defect in the active phase.