Objective To determine safe zones at the medial and lateral calcaneus for percutaneous pin placement in Chinese patients.Methods Fourteen cadaveric specimens of normal Chinese adult foot and ankle joints were dissected in this study.At the medial calcaneus of each foot, the most medial and posteroinferior point, the most inferior medial malleolus and the navicular tuberosity were identified and labeled as points A, B and C respectively.The medial calcaneal nerve, the most posterior branch of the lateral plantar nerve, the lateral plantar nerve, the medial plantar nerve, the posterior tibial artery, the lateral plantar artery and the medial plantar artery were carefully dissected and identified.A relative safe zone at the medial calcaneus was marked off according to where the neurovascular structures crossed lines AB and AC.At the lateral calcaneus, the most lateral and posteroinferior point and the inferior lateral malleolus were identified and labeled as points D and E respectively.The lateral calcaneal nerve, the sural nerve and the trunk of the small saphenous vein were carefully dissected and identified.A relative safe zone at the lateral calcaneus was marked off in the same way as that at the medial calcaneus.Results At the medial calcaneus, the medial calcaneal nerve, the most posterior branch of the lateral plantar nerve, the lateral plantar nerve, the medial plantar nerve and the posterior tibial artery crossed line AB respectively at posteroinferiorly 22%, 50%,56%, 64% and 58% of the line.The medial calcaneal nerve, the most posterior branch of the lateral plantar nerve, the lateral plantar nerve, the medial plantar nerve, the lateral plantar artery and the medial plantar artery crossed line AC respectively at posteroinferiorly 14%, 39%, 49%, 63%, 41% and 57% of the line.At the lateral calcaneus, the lateral calcaneal nerve, the sural nerve and the trunk of the small saphenous vein crossed line DE respectively at posteroinferiorly 19%, 65% and 61% of the line.Conclusions At the medial calcaneus, the circular region posterior to the 1/2 of line AB and to the 1/3 of line AC may be considered as a relative safe zone for percutaneous pin placement; at the lateral calcaneus, the region posterior to the perpendicular at the midpoint of line DE may be considered as a relative safe zone for percutaneous pin placement.

[Objective]To observe the changes of contact characteristics of the subtalar joint after calcaneus fracture in load condition, so as to provid a theoretical basis for its clinical treatment.[Method]Six fresh speciments consisting of foots and lower legs were harvested.A specimen,including an intact foot and 15~20cm of the distal tibia and fibula prepared by removing the skin,muscle and tendons down to the level of the hindfoot and the ligaments and joint capsules were kept intact with the exception of the posterior aspect of the posterior facet and the lateralaspect of middle and anterior facets of the talocalcaneal joint.The pressure sensitive film was inserted into the posterior and anterior-middle facets of the talocalcaneal articulation,and 500-N load was applied in the neutral position.After testing of the intact foot,the calcaneus was splited into anterointernal and posterolateral compoments using microoscillating saw to simulate primary fracture of calcaneus.The test was repeated after tile posterolateral fragment was anatomically reduced and displaced 2mm,5mm and 10mm respectively in a planter direction.The changes of contact characteristics of the subtalar joint ware recorded.[Result]The average pressure area of the intact posterior facet was(275.67?46.02) mm~2,the average stress to bear the weight was(1.83?0.56) MPa.The bearing average pressure area decreased to(167.67?25.09) mm~2 when the posterolateral compoment was displaced to plantar in 2 mm,it was significantly lower(P0.05).The bearing stress the anterior and middle facets significant increased only in a 1 10mm plantar displacement of the posterolateral component(P

[Objective]To evaluate the effect of fibula shortening on biomechanical characters of tibiotalar joint and prescribe the most acceptable extent of fibula shortening.[Method]Six fresh cadaveric specimens were disarticulated though the knee,and the soft tissues were removed from the knee to the level of the ankle joint.The position of the ankle joint during testing simulated the single leg stance phase of gait.Every group of specimen carried out a biomechanical test in the turn of intact,fibula 2mm shortening,4mm shortening,6mm shortening.The biomechanical change of the tibiotalar joint after fibular shortening was found.[Result]The total contact area of the tibiotalar joint tended to decrease in the fibular shortening model.The contact area and contact pressure in anteromedial and posteromedial quadrant tended to decrease,while,the contact area and contact pressure in anterolateral and posterolateral quadrant tended to increase.[Conclusion]The 2 mm fibular shortening(including 2 mm) significantly alter the biomechanical characters in tibiotalar joint.

[Objective]Through the clinical investigation of the conversative treatment of undisplaced femoral necks,to analyze the occurrence of secondary displacement and femoral head necrosis.[Method]The medical records of 216 patients with undisplaced femoral neck fractures who were primarily treated conservatively from January,2000 to January,2004 were analyzed.Among that,186 cases is in accordance with the selected standard,which were consisted of 82 men and 104 women.(the average age 67.5).One hundred and forty-one fractures were given to bed rest in rotation-proof shoes,and walking on the crutches was followed after four weeks.Forty-five patients began to get out of bed with double crutches on the third day.When displacement happened,the operation was carried out.Once X-rays showed the fracture line unclearly,it is considered as bone healing.The early stage of femoral head necrosis was defined by sclerotic region or cyst in the femoral head.[Result]Sixty-eight fractures(36.6%) united and secondary considered displacement occurred in 118 cases(63.4%); the average time was 16 days (2～68 d) after injury when the displacement is found.In all primary healing patients,femoral head necrosis rate was 25%.The discovery time of necrosis was between 4 and 18 months,the most was 36 cases in the interval of 6 to 12 months.As for patients of secondary displacement,92 for closed reduction and hollow screws fixation,and the head necrosis happened in 55 patients(59.8%).The discovery time was from 4 to 18 months,the most in 6 to 12 months was 36 cases.The operation of open reduction and internal fixation with hollow screws was in 26 cases,73% of necrosis rate for it.The time was range from 3 to 12 months,11 case was the most in the period of 3 to 6 months.[Conclusion]Undispalced femoral neck fractures treated conservatively bear higher risk of secondary displacement and femoral head necrosis.In addition with more mortality and general complications,we therefore recommend primary operative stabilization of undisplaced femoral neck fractures.

Objective To assess the efficacy of double-level bone transport for treatment of extensive post-infectious tibial bone defects.Methods From January 2010 to May 2014,12 consecutive patients suffering from massive postinfectious tibial bone defects were treated by the Ilizarov technique of double-level bone lengthening.The study population included 8 males and 4 females,with mean 40.9 years (range,16-65 years).Mechanisms of initial injury included motor-vehicle injury in eight patients,explosive injury in two and crush-related injury in two.After bony resection for infection,skin defect was 8.7 cm ×5.8 cm (range,4.5 cm × 2.0 cm-20.0 cm × 10.0 cm) and bone defect averaged 11.0 cm (range,6.0-20.0 cm).All patients were treated with a double-level transport (three distal-to-proximal,six both-ends-to-center and three proximal-to-distal).Three patients were candidates for flap coverage before bone transport because of large wounds,one patient had direct closure of the wound after tibial partly shortening,and the remaining patients kept the wound open during bone transport.Bone and functional results were evaluated according to the criteria given by Association for the Study and Application of the Method of Ilizarov (ASAMI).Results After removal of the apparatus,follow-up was (30.0 ±5.6) months (range,12-36 months).All patients achieved complete union and successful eradication of infection.Mean bone transport time was (55.4 ± 26.2)d (range,30-125 d),with the lengthening index of (5.0 ± 0.6) d/cm (range,3.9-6.3 d/cm).Wound union time was (3.6 ± 1.4) months (range,1.5-6.0 months).Mean consolidation time of the distraction gap was (10.9 ± 3.8)d (range,4.0-18.0 d).Mean union time of the docking site was (8.4 ± 3.8)months (range,3-16.5 months).Mean external fixation time was (12.5 ±4.1)months (range,5-18 months),and mean external fixation index was (1.2 ± 0.3) months/cm(rang,0.8-2 months/cm).According to the ASAMI,bony results were excellent in seven patients (58％) and poor in five (42％);functional results were excellent in nine patients (75％) and good in three (25％).Conclusion Double-level bone transport is an effective method that can reduce bone transport time and external fixation time.

Objective To assess the efficacy of using the Ilizarov bone transport combined with open bone grafting and vacuum sealing drainage (VSD) to treat infected tibial bone defect.Methods A retrospective case series study was made on 8 patients sustaining posttraumatic infectious tibial bone defect treated between March 2010 and May 2015.There were 7 male and 1 female patients between 22 and 51 years (mean,39.4 years).All patients underwent radical resection of the infected/necrotic bone and debridement of the soft tissue.Length of bone defects after debridement averaged 8 cm (range,3.5-13.5 cm) and wound size averaged 4.8 cm ×2.5 cm (range,2.3 cm× 1.1 cm-8.5 cm ×6.0 cm).Stabilization was finished with Ilizarov circular external frame in all patients.Six patients were candidates for single-or double-level bone transport,and the cancellous bone autograft was placed openly within the butterfly defect after docking.Other 2 patients were treated with one-stage shortening of the fracture ends and open cancellous bone grafting,and the bone lengthening was performed.Then the grafted wounds were covered by VSD.Data were recorded including the bone transport or lengthening time,wound healing time,union time of docking sites,consolidation time of regenerate zones,external fixation time and external fixation index.Bone results and functional results were evaluated according to the criteria given by association for the study and application of the method of Ilizarov (ASAMI).Results Duration of follow-up was 10.2-36.4 months (mean,12.2 months).All the wounds achieved successful healing and eradication of infection.Mean bone transport time was 50 days (range,30-69 days).Seven patients showed selfhealing wounds,and mean healing time was 3.4 months (range,1.2-6 months).One patient experienced wound closure by skin grafting.Union and consolidation were achieved in all docking sites and regenerate zones.Mean union time of docking sites after bone grafting was 6.8 months (range,5.3-10 months).Mean consolidation time of regenerate zones was 6.2 months (range,4.8-8.5 months).Mean external fixation time was 8.6 months (range,6.5-11.5 months) with a mean external fixation index of 1.2 months/cm(range,0.7-1.9 months/cm).According to the criterion of ASAMI,bony results were excellent in 7 patients and poor in 1 patient,and functional results were excellent in 4 patients and good in 4 patients.Conclusion Ilizarov bone transport technique combined with open bone grafting and VSD for infectious tibial bone defect can accelerate bone union and wound healing at docking sites and reduce external fixation time.

Objective To evaluate the effect of internal iliac artery or abdominal aorta blockade on the pressure of internal iliac artery net in order to provide theoretical basis for reasonable option of arterial blockade in management of arterial bleeding of pelvic fractures.Methods Five goats were included in the study.The measurement of the pressure of internal iliac artery net was made in the following steps:( 1 ) measurement of the pressure of normal internal iliac artery,(2) measurenent of the pressure following blockade of unilateral internal iliac artery,(3) measurement of the pressure following blockade of bilateral internal iliac arteries,(4) measurement of the pressure following blockade of abdominal aorta and bilateral internal iliac arteries simultaneously,(5) measurement of the pressure following blockade of abdominal aorta only.Results The normal internal iliac artery pressure was ( 57.84 ± 13.46 ) mm Hg.The pressures following the blockade of unilateral internal iliac artery,bilateral internal iliac arteries,abdominal aorta and bilateral internal iliac arteries sinultaneously,and abdominal aorta only were (38.40±17.39) mm Hg,(29.70 ± 12.16) mmHg,(32.80 ± 17.02) mm Hg and (29.20 ± 18.52) mm Hg,respectively.All the blocking designs had obvious effect on the pressure of normal internal iliac artery ( P ＜ 0.05 ),while the various blockade modes themselves showed no statistical differences (P ＞ 0.05). Conclusion The upper described four modes of blockade are similar in decreasing the pressure of the internal iliac artery net.Thereby,only one of them is enough in management of artery hemorrhage following pelvic fractures.

Objective The tissue engineering technique and the microsurgery technology is combined to construct the uncellular tissue engineering complex with vascularization and membrane guided dual effect. Through comparing study of using the simple biomembrane guided bone regeneration technique to construct the uncellular tissue engineering complex to repair the large segment bone defect in the animal body,the bone reparative effect of the tissue engineering bone wrapped by pedical fascial flap with vessels and that wrapped by the simple biomembrane was compared, thus to provide experimental evidence for the clinical application. Methods Twenty-four Newzland 5-month-old rabbits were used to build the bilateral periosteumincluded bone defect modelsin the middle piece of the ulna and the length of the defect was 1 cm. Autologous red bone marrow was implanted in the tissue engineering bone which was prepared by osteoinductive absorbing material including BMP. The prepared tissue engineering bone was implanted in the bone defect area. The right side was wrapped by the simple absorbable biomembrane, whereas the left side was wrapped by pedical fascial flap with blood supply. At the fourth, eighth, twelfth and sixteenth week after the operation each group was examined by the radiograph (x-ray), the light density measurement, gross morphology and histological inspection,bone shape measurement analysis in the repairing area and the biomechanics measurement at the twelfth week. The data was analyzed to test the difference of the bond defect repair. Results The radiograph, gross morphology and histological inspection showed the growth of vessels in the implant area, the quantity and the forming speed of the bone trabecula and, the cartilaginous tissue, the formation of the mature bone structure,remodeling of the diaphysis, recanalization of the cavum ossis and the absorption and the degradation of the implant of the group of pedical fascial flap with blood supply was superior to that of the group of the simple absorbable biomembrane. At the fourth, eighth, twelfth and sixteenth week after the operation the bone trabecula area were( 20. 35 ± 2. 41 ) %, ( 40. 21 ± 1.97 ) %, (66. 67 ± 3.44 ) % and ( 86. 47 ± 3.99) % respectively in the group of pedical fascial flap with blood supply, and were ( 7. 46 ± 2.64 ) %, ( 20. 66 ± 2. 28 ) % , ( 40. 22 ±1.84)% and(58. 18 ± 1.79) respectively in the group of the simple absorbable biomembrane. At the same time point after the operation the light density were 0. 636 ± 0. 012,0. 596 ± 0. 062,0. 552 ± 0. 009 and 0. 451 ±0. 008 respectively in the group of pedical fascial flap with blood supply, and 0. 742 ± 0. 032,0. 713 ± 0. 022,0. 655 ±0. 018 and 0. 606 ±0. 015 respectively in the group of the simple absorbable biomembrane. The units of blood vessel reproductive area in the bone repair junctional zone were ( 18.75 ± 2. 09 ) %, ( 37.41 ± 3.22 ) %,(53. 06 ±2. 18)% and (36.72 ±4. 73)% respectively in the group of pedical fascial flap with blood supply,and (5. 34 ± 1.17 ) %, (9. 48 ± 2.96) %, ( 22.43 ± 2. 21 ) % and ( 26. 27 ± 3. 14 ) % respectively in the group of the simple absorbable biomembrane. The biomechanics intension was 26.62 ± 3.96 in the group of pedical fascial flap with blood supply and 18. 38 ±0. 71 in the group of the simple absorbable biomembrane at the twelfth week after the operation. All of the differences were significant( P ＜0. 05 ). Conclusion The pedical fascial flap with blood supply has significant effect in promoting the tissue engineering bone to vascularize and promoting the bone formation by vascularization. The membrane guided bone regeneration technique restricted not only the growth of the fibrous connective tissue in the reparative process of the large segment bone defect effectively, but also the ability of fast and effective vascularization, thus the chronic creep and substitution process would be needed. Simple application of the biomembrane can compensate the shortcoming of chronic creep of the implanted material by the growth of the external callus.

Objective To evaluate the biomechanical effect of cortical screw support technique in fixation of the femoral neck fractures. Methods The models of subcapital femoral neck fracture were made in eight matched pairs of embamled cadaver femurs and decided into experiment group and control group (four pairs per group). The side of experiment group was fixed using three cannulated compression screws with cortical screw support and that of control group with conventional screw placement. The speci-mens in two groups were tested in aspects of torsion and axial loading. Results In axial load test at load of 600 N and 800 N, the displacements in cortical screw support group were (0.677±0.135) mm and (0.907±0.132) mm respectively, while those of femoral head in conventional screw placement group were (0.899±0.160) mm and (1.202±0.152) nun respectively (P <0.05). There was signifi-cant difference between the two groups (P < 0.05). The maximal vertical loading for failure of the fixa-tion was (2 782±228) N in cortical screw support group and (1 950±281) N in conventional screw placement group (P < 0.01). In torsibility test at 4° and 6° torsibility, the torque-moments of cortical screw support group were (10.406±1.515) Nm and (15.328 ±1.471) Nm respectively and those of conventional screw placement group (6.628±1.163) Nm and (9.072±1.570) Nm respectively, with statistical difference between two groups (P <0.01). The maximal torque-moment for failure of the fixa-tion was (25.437±5.213) Nm in cortical screw support group and (13.235±3.012) Nm in conven-tional screw placement group (P < 0.01). Conclusion Fixation of femoral neck fractures by using cortical screw support can significantly enhance anti-torsion and anti-compression of internal fixation.

Objective To determine the curative effect of stabilizing unstable pelvic ring fracture using the anterior subcutaneous internal fixator (INFIX).Methods From July 2013 to June 2014,15 cases who suffered from anterior pelvic ring fracture were treated with the device.There were 11 males and 4 females,with mean age of 38.5 years (range,23-65 years).Eight cases sustained fracture in traffic accidents,4 in high falls,and 3 in crush injury.According to the Young-Burgess and AO/OTA classification systems,type APC2 or 61-B1 was noted in one case,LC1 or 61-B2.1 in 4 cases,LC2 or 61-B2.2/61-B2.3 in 6 cases,and VS or 61-C1/61-C2 in 4 cases.Basic method in anterior ring fixation was one pedicle screw was respectively inserted into the area between the anterior superior iliac spine and anterior inferior iliac spine of both sides.The precontoured rod was then tunneled subcutaneously from one screw to the other.For the stable posterior injury in pelvic ring fracture,the anterior pelvic ring was stabilized only using the technique.For the unstable posterior injury in pelvic ring fracture,the anterior and posterior ring were both fixed using the technique.During follow-up visits,patients' tolerance to the device,wound infection,myositis ossificans,internal fixation lessening,and lateral femoral cutaneous nerve injury were evaluated.Results Follow-up ranged from 6-12 months (mean,7.5 months).The device was well tolerated by the patients for comfort.None had surgical site infection and internal fixation loosening.Injuries healed without loss of reduction at the 3-month follow-up.Injury of the lateral femoral cutaneous nerve at the both side was reported in 4 cases and at one side in 2 cases,but all restored 3 month after operation.Conclusion The reported technique is minimally invasive with few complications and reliable results,hinting an ideal method to stabilize the anterior pelvic ring fracture.