Objective To discuss the complications following internal fixation of intra-articular calcaneal fractures and its prevention and treatment. Methods From January 1997 to July 2002, 59 sides of calcaneal fractures in 54 patients were treated with open reduction and Y-shaped plate fixation through lateral approach, most of them supplemented by autogenous bone grafting. According to Sanders classification, 20 sides were accounted for typeⅡ, 24 for type Ⅲ, 15 for type Ⅳ. During operation, lateral roentgenograms were made to assess Bler angle and Gissane angle, Broden view was made to evaluate congruency of the posterior facet. The wounds were drained underneath the lateral flap to prevent hematoma formation. Perioperative antibiotics were used routinely. All the cases were followed-up for an average of 17 months(range, 9 to 48 months). Results The clinical results were evaluated according to Maryland Foot Score, excellent results achieved in 30 cases, good in 21, fair in 6, poor in 2; excellent and good rate was 86.4%. Early complications were found in 4 cases(6.8%). Among them, 2 cases of wound necrosis were treated with suture after resection of necrotic tissue or covered with flap grafts, 1 case of wound infection recovered after dressing changes, 1 case of sural nerve injury recovered uncompletely without any special treatment. Late complications were found in 2 cases(3.4%) with obvious chronic pain, the patients were treated by subtalar arthrodesis and relieved from pain later. Conclusion The complications of internal fixation to fractures are related to anatomic features of calcaneus and their injury mechanism. Serious complications can be minimized in several ways as follows: optimal time for operation and preoperative design should be carefully considered, a full-thickness flap is recommended in avoidance of excessive distraction, bone grafting is needed to support intra-articular fracture fragments and to enhance the stability of internal fixation, the affected extremity should be immobilized by plaster and elevated, and perioperative use of antibiotics.The appropriate management should be taken in cases of complications.

[Objective]To explore the effect of continuous physiological osteogenic stress on the bone healing of canine iliopectineal crest.[Method]Ten adult mixed breed dogs without significant individual difference were made transverse fracture at bilateral iliopectineal crest 1.5 cm above the dome of acetabulum,which were fixed with ATMFS or steel plate respectively. The animals were sacrificed and specimens were procured at 2,4,6,8 and 12 weeks after operation.Samples from the fracture gaps were investigated by histology of HE and Masson staining,image pattern analysis of new bone formation.[Result]The formation of cartilaginous tissue and the maturity of cortical and trabecular bone and collagen fibers of ATMFS sides were earlier than that of steel sides obviously.There was significant difference of the integrated optical density (IOD) of new bone formation between two groups (P

Objective To introduce a new technique for treatment acetabular fractures with nitinol tridimensional internal fixation system. Methods According to the characteristics of nitinol and acetabular anatomy, a new internal fixation system for acetabular fracture, acetabular tridimensional memoryalloy-fixation system (ATMFS), was designed. This system consisted of anterior column, posterior column, arch teeth and trochanter device. During operation, these devices were transformed in iced water first, after fracture reduction they were inserted into bones, finally, these devices were reverted to their original shape by warm saline. Till October 2001, 41 cases acetabular fractures were treated with this system. All these cases were followed from 6 to 28 months. Results This system could transform the complicated and comminuted fracture to its anatomic position, and was easy to use in operation. Bone healing time averaged 1.6 months in 38 cases, and the hip function recovered time averaged 2.5 months. Heterotopic ossification which led to joint functional disturbance in one case, and myositis ossificans which caused joint dysfunction in two cases. One case was complicated by infection which was cured and good function was reserved. Conclusion ATMFS provides a new and efficacious method for the anatomic reduction or reconstruction of comminuted acetabular fractures.

Objective To introduce a new technique for vascular pedicle elongation in island flap transplantation, and evaluate its clinical results. Methods From February 1994 to October 2001, 16 cases were treated with island flap transplantation with Y-V vascular pedicle elongation technique. There were 10 males and 6 females with the age ranging from 19 to 45 years ( average 26.8 years). The locations of the primary injury were as follows: the fingers in 6 cases, the great toe in 2 cases, the other toes in 2 cases, the knee joint in 3 cases and the proximal tibia in 1 case. The flaps vascularized by a branch of "Y" pattern bifurcation were used. Both branches of "Y" shaped vascular pedicle arising form the same main vessel trunk were dissected, then the main vessel trunk was severed at the division of the branches, the arc of "Y" bifurcations was then turned into "V" pattern, the length of pedicle was significantly elongated than the original pedicle. Results The operative procedures were smooth in the patients, and all of the flaps were successfully transferred, the elongated length of pedicle ranged from 3 cm to 12 cm, with the average length of 6 cm. The transplanted island flaps were rich in blood supply, and the vascular pedicle were not tight. No vascular crisis signs occurred, and the island flaps survived in all patients with stage I of wound healing. The quality and color of the flaps were similar to the skin of receptive area. Conclusion The lengthening technique of Y-V vascular pedicle can enlarge not only the scope of application for island flaps, but also improve the success rate of flap transplantation.

Objective To explore the effects of swan-like memory compressive connector(SMC) made of Ni-Ti shape memory alloy on stress shielding rate, struct ure and mechanical properties as well as the blood flow of cortical bone of expe rimental fracture healing. Methods Mid-shaft osteotomies of bilateral humerus we re performed in 56 rabbits. One side was randomly fixed with SMC, and the other side was plated with a 4-holes dynamic compressive plate (DCP). At 2, 4, 8, 12, 16,and 20 weeks after operations, the humeri in 8 rabbits were harvested. The st ress-shielding rate was measured using axial compressive test in situ samples. T he geometrical structure and bone density were examined by CT scans, and the mec hanical property was assessed by torsion tests. Blood flow was measured in real time using Laser-Doppler flowmetry. The cortical bone perfusion of 16 rabbits wa s measured at 10 time intervals (after periosteotomy, after fracture, instant af ter fixation, at 1, 3, and 7 days, and 2, 4, 8, and 12 weeks postoperatively). B lood flow was measured at outer and inner cortical bone beneath the fixation. Si multaneously, anteroposterior radiograph of the humerus was taken. Results The s tress-shielding rate in SMC group was significantly lower than that of DCP group (P

Objective To explore effect of swan-like memory connector (SMC) on bioelectric potential changes during the course of experimental fracture healing and its relation with fracture healing. Methods Bilateral humerus of 33 New Zealand rabbits were osteotomized in midshaft. One random side was fixed with SMC and the other one plated by the four-hole dynamic compression plate (DCP). The bioelectric potential changes of the fractured humerus in eight animals were determined using modified Friedenberg's technique,at eight time intervals (prefracture,postfracture,postfixation immediately,1, 2,4,8 and 12 weeks after surgery). The rabbits were killed at the 1st,2nd,4th,8th and 12th weeks respectively postoperatively and the humerus in 5 rabbits harvested for HE sections. Results The bioelectric potential of fracture site remained invariably negative all the time in the Group SMC. However,the bioelectric potential began to recover from the 2nd week after operation and reached the normal level of prefracture at the 4th week in the Group DCP,with a significant difference compared with the Group SMC ( P

[Objective]To explore the cause and treatment of refractory nonunion of patella combined with handicapped joint function.[Method]Retrospective analysis was given to twenty-four patients diagnosed as patellar nonunion that had been admitted to our hospital from Jan 1992 to Jan 2006.The series included fifteen males and nine females with an average age of 36(range 12-71) years.Initial treatment of the original fractures was nonoperative in 3,cerclage with wiring or suture silk in 11,tension band wiring in 6 and modified tension band wiring in 4.All fractures progressed to symptomatic nonunion at an average of 18 months from original injury(range 5-32).All patients were given open reduction and internal fixation,which consisted of Nickel-Titanium patella concentrator(NT-PC) in 9,NT-PC combined with cannulated compression screws in 6,combined with Kirschner wire in 5 and tension band wiring in 4.[Result]Twenty-four patients were followed up with an average of 35(range 6-168) months.The time of bone union averaged 4.2(range 3-6) months.No bone block displacement,loosening or breakage of internal fixation happened.According to Xu Shaoting' s knee function scores,the results were excellent in 14 cases,good in 6 cases,fair in 3 cases and poor in 1 cases.The excellent and good rate was 83.3%.[Conclusion]Operative reconstruction of smooth joint surface,rigid internal fixation and early functional exercise are effective remedies to refractory nonunion of patella combined with handicapped joint function.

[Objective]To evaluate the effect of continuous dynamic pressure stress on experimental humeral fracture healing and to explore the role of COX-2 /PGE2 /cAMP signaling pathway in healing promotion induced by the special biomechanical condition.[Method]A total of 120 New Zealand rabbits were divided randomly into three groups: Group A,unilateral humeral fracture was fixed with shape memory connector(SMC),producing axial continuous dynamic pressure stress on fracture gap.Group B,fixed with 4-hole DCP,and Group C,fixed with SMC and gavaged with aqueous suspensions of celecoxib(3 mg/kg/day) after fracture.COX-1 and COX-2 mRNA expressions in fracture gap were determined by real-time RT-PCR at 0,3,7,14,21,28 and 56 days after operation,as well as the contents of PGE2 and cAMP were measured by radioimmunoassay(RIA).Bone-specific alkaline phosphatase(B-ALP) activity was determined by measuring p-nitrophenol and osteocalcin concentrations were measured using enzyme-linked immunosorbent assay(ELISA) for serial collected blood samples.Callus specimens fixed by formalin were used for histopathological examination.[Result]The COX-2 mRNA levels normalized with GAPDH mRNA as well as the contents of PGE2 and cAMP showed significant difference along with the 56-day period and also between the two internal fixations.Histopathological observation and determination of serum biochemical markers of bone formation revealed that the endochondral bone formation and the callus remodelling took place earlier in Group A than in Group B.The accelerated healing process and increased serum values of the bone formation markers induced by continuous dynamic pressure stress of SMC were inhibited by celecoxib,a specific COX-2 inhibitor.[Conclusion]The persistent dynamic longitudinal pressure stress produced by SMC contributed to endochondral bone formation and callus remodelling,resulting in an acceleration of fracture healing,which was considered to be closely correlated with the COX-2/PGE2/cAMP signal transduction pathway.

Objective To explore the effect of persistent stress on the ultrastructure of cancellous bone in the process of fracture healing.Method A transverse osteotomy on both sides of the femoral tuberositas was performed in 20 adult dogs. One side was fixed with a self-designed tuberositas memofy-pressure connector (TMC) which was made of NiTi shape memory alloy, and the other with compressive steel-wire (SW) cerclage.Five animals in each group were sacrificed at 2, 4, 8, 12 weeks after operation and observed under transmission electron microscope.Results The fracture healing was accelerated in the TMC group.The osteoblasts, chondroblasts and collagen fibers at the fracture sites showed significantly different morphology between the 2 groups at every observation time.Most cells and collagen fibers in the TMC group grew along the same direction as the stress, but those in the SW group grew in disorder.Both the number and functional activity of the osteoblasts and chondroblasts were higher in the TMC group than in the SW group.Conclusion Persistent stress can enhance healing and bone reconstruction following a cancellous bone fracture.

Objective To investigate the effects of swan shaped memory connector(SMC) on the bone mineral density and mechanical properties of humeral fracture in rabbits in order to disclose the mechanism of SMC stimulating fracture healing. Methods Shafts of both humeri of 40 rabbits were osteotomized. One side was selected to fix with SMC, but the contralateral side was fixed with the 4 hole dynamic compression plate (DCP). Eight rabbits were sacrificed and the humeri were harvested respectively at 2, 4, 8, 12 and 16 weeks after operation. The bone mineral density(BMD) was examined by dual energy radiographic absorptiometry(DRA). The mechanical properties were assessed by mechanical traction test. Results From 4 to 16 weeks after operation, the BMD in SMC group was significantly higher than that in DCP group ( P