Objective To construct a lentiviral vector of RNA interference (RNAi) of PKCγ gene. Methods The effective sequence of siRNA targeting PKCγ gene was confirmed in our previous study. The complementary DNA containing both sense and antisense oligo DNA of the targeting sequence was designed, synthesized and cloned into the pGCSIL-GFP vector, which contained U_6 promoter and green fluorescent protein (GFP) . The resulting lentiviral vector containing PKCγshRNA was named lentivinis RNAi vector of PKCγ, and it was confirmed by realtime PCR and sequencing. 293T cells were cotransfected with lentiviral vector pGCSIL-CTP, pHelper 1.0 and pHelper 2.0. All virus stocks were produced by calcium phosphate-mediated transfection. The titer of virus was tested according to the expression level of GFP. Results PCR and DNA sequencing demonstrated that the lentivirus RNAi vector of PKCγ producing PKCγshRNA was constructed successfully. The titer of concentrated virus was 1 ×10~9 TU/ml. Conclusion The lentivinis RNAi vector of PKCy was constructed successfully.

Objective To compare cable tension band fixation with other 3 fixations in terms of biomechanical stability for tibial avulsion fractures of the anterior cruciate ligament (ACL).Methods Eighty fresh porcine knees were randomized into 4 equal groups (n =20).For each knee,all the soft tissues were removed only to keep the femur-ACL-tibia complex.The knee complexes were used to create fracture models of standard Meyers-Mc Keever type Ⅲ at the ACL attachment region using a swing saw.The fracture fragments in the 4 groups were subjected to fixation respectively with intramedullary lag screws,high-strength suture,tension band wire and cable tension band.All the specimens were subsequently tested on a Material Testing Machine at a load rate of 60 mm/mm.The 4 groups were compared in terms of ultimate failure load,yield load,and fragmental displacement under single-cycle loading and multi-cyclic loadings.Results Cable tension band fixation displayed significantly higher ultimate failure,higher yield load and lower fragmental displacement than all the other 3 fixations (P ＜ 0.05).Conclusion As cable tension band fixation,which is convenient and economical,provides better biomechanical stability than other 3 fixations for tibial avulsion fractures of the ACL,it may allow earlier functional and weight-bearing exercise after operation.

Objective To investigate the therapeutic effect of anteromedial ankle approach for talus fracture.Methods From January 2012 to October 2018,the data of 28 cases of talus fracture treated by anteromedial ankle approach were retrospectively analyzed,including 26 males and 2 females,aged 24-61 years with an average of 38.6 years.All 25 cases of closed injuries and 3 cases of open injuries were fresh injuries.There were 16 cases of traffic injuries,8 falling injuries,2 heavy object injuries and 2 sprains.Among the 28 patients,17 were talus neck fractures,and according to Hawkins talus neck fracture classification,there were 1 case of type Ⅰ,12 type Ⅱ,and 4 type Ⅲ.There were 11 cases of talus fracture,which were classified according to Sneppen talus fracture types:2 cases of type Ⅰ,8 cases of type Ⅱ and 1 case of type Ⅴ.Among them,2 cases of talus neck fracture complicated with T12 vertebral body fractures and 2 cases complicated with calcaneal fractures.The time from injury to operation for 3 patients with open fracture was 3-6 hours.25 cases of closed fracture injuries took 2-10 hours to operate,with an average time of 5.6 hours.All patients were fixed with cannulated screws through the anteromedial ankle approach.The weight-bearing time and strength of lower limbs were determined according to fracture healing after surgery.The ankle function was evaluated by American Orthopaedic Foot and Ankle Society (AOFAS) Score.Results All 28 patients were followed up for 23 to 82 months,with an average of 37.5 months.All fractures healed.The healing time of talus neck fracture was 3.5-8 months,with an average of 5 months.The healing time of talus fracture was 3-7 months,averaging 4.5 months.At the latest follow-up,AOFAS score ranged from 68 to 100,with an average of 82.5 points,including excellent in 15 cases,good in 8 cases,fair in 4 cases and poor in 1 case,with the excellent and good rate of 82.1％ (23/28).There were no signs of fracture displacement,malunion,loosening and prolapse of internal fixation,fracture and ischemic necrosis of talus after operation.Traumatic arthritis occurred in 9 patients,with an incidence rate of 32.1％ (9/28).Tibial joint was involved in 5 cases,talus joint in 3 cases,tibialis in 1 case and talus joint in 1 case.Among them,traumatic arthritis occurred in 2 cases of open injury.Nine patients (32.1％) suffered from traumatic arthritis 6-10 months after operation,with an average of 8 months.According to conservative treatments such as weight control,ankle immobilization,physiotherapy,anti-inflammatory and analgesic,nutrition of articular cartilage drugs,joint traction and plasty were given.The patients' conditions improved to different degrees and could tolerate walking and normal life and work.Conclusion The anteromedial ankle approach has the advantages of minimal vessel injuries,clear exposure for direct reduction,low rate of necrosis of talus and satisfactory curative effect.