BACKGROUND:Artificial hip replacement by the posterolateral approach is generally introduced as a treatment for femoral neck fracture in the elderly, but it is limited by the need for a large incision, cutting off the extortor, and postoperative hip dislocation. The supercapsular percutaneously-assisted total hip (SuperPATH) approach was developed based on the original lateral approach. The SuperPATH approach for hip replacement is characterized by the reduced chance of damaging blood vessels and nerves, reducing intraoperative blood loss, retaining all the joint capsules and supinator, and significantly reducing the incidence of postoperative hip dislocation. OBJECTIVE:We hypothesized that the SuperPATH approach for hip replacement can achieve better efficacy in the elderly with femoral neck fractures and promote the recovery of postoperative hip function compared with the posterolateral approach. METHODS/DESIGN:This is a prospective, single-center, open-label, randomized control ed clinical trial that will be completed at the Pudong Hospital of Fudan University, Shanghai, China. Forty patients with femoral neck fractures were randomly divided into two groups to undergo femoral head replacement by the SuperPATH approach in the experimental group, and by the conventional posterior approach in the control group. The follow-up period is 1 week and 6 months. The main outcome measures are Harris hip scores at baseline, and at 1 week and 6 months postoperatively to assess functional recovery of the hip. Secondary outcome measures to evaluate the advantages of the SuperPATH approach include the length of surgical incision, intraoperative blood loss, operative time, 24-hour postoperative drainage, and hospital stay. Other outcome measures include the incidence of adverse reactions at 1 week and 6 months after surgery. The study protocol was approved by the Ethics Committee of the Pudong Hospital of Fudan University, China, and performed in accordance with the guidelines of the Declaration of Helsinki, formulated by the World Medical Association. Written informed consent was obtained from all participants. DISCUSSION:The aim of this trial is to test our hypothesis that the SuperPATH approach is safer and more reliable for hip functional recovery compared with the posterolateral approach for the artificial hip replacement in femoral neck fractures of the elderly.

BACKGROUND: Three-dimensional (3D) printing technique has showed unparalleled advantages in the field of tissue engineering scaffold preparation because of its outstanding merits of convenience, efficiency, controllability and ability to construct complex shapes.OBJECTIVE: To fabricate Fe-containing mesoporous calcium-silicate (MCS) /poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) composite scaffolds using the 3D printing technique and to test the characterization and cellular biocompatibility of the composite scaffolds.METHODS: Four groups of Fe-containing MCS/PHBHHx composite scaffolds were fabricated using 3D printing technique. The molar percentage of Fe in these four groups was 0%, 5%, 10%, 15%, respectively and they were marked as 0Fe-MCS/PHBHHx, 5Fe-MCS/PHBHHx, 10Fe-MCS/PHBHHx and 15Fe-MCS/PHBHHx. The scanning electron microscopy was used to observe the microstructure of the scaffolds after being soaked in the simulated body fluid.Osteoblast cell lines MC3T3-E1 were seeded on these four groups of scaffolds as well. Cell counting kit-8 method was adopted to test the cell proliferation at 1, 3, 7 days of culture. Intracellular alkaline phosphatase activity was tested at 7 and 14 days of culture.RESULTS AND CONCLUSION: (1) Compared with the scaffolds with no soaking process, spherical particles were formed on the scaffolds because of mineralization after soaking 3 days in the simulated body fluid. (2) At 1 day of culture,there was no difference in cell proliferation among the four groups. At 3 days of culture, the proliferation rate of the 15Fe-MCS/PHBHHx scaffold was remarkably higher than that of the rest three groups (P < 0.05). At 7 days of culture,the proliferation rate was significantly higher in the 10Fe-MCS/PHBHH and 15Fe-MCS/PHBHHx scaffolds than the 0Fe-MCS/PHBHH scaffold (P < 0.05), as well as significantly higher in the 15Fe-MCS/PHBHHx scaffold than the 10Fe-MCS/PHBHH scaffold (P < 0.05). (3) At 7 days of culture, no difference in alkaline phosphatase activity could be found among these four groups of scaffolds; however, at 14 days, the 5Fe-MCS/PHBHHx, 10Fe-MCS/PHBHHx and 15Fe-MCS/PHBHHx scaffolds exhibited an enhanced alkaline phosphatase activity compared with the 0Fe-MCS/PHBHHx scaffold. Meanwhile, the 15Fe-MCS/PHBHHx showed the highest alkaline phosphatase activity.These findings indicate that the MCS/PHBHH scaffolds containing Fe could promote the proliferation and osteogenic differentiation of the MC3T3-E1 cells.

BACKGROUND:Macropore morphology of a composite scaffold prepared by the three-dimensional printing technique is of great importance in determining the physicochemical and biological properties of tissue engineering scaffolds.OBJECTIVE:To fabricate strontium-containing mesoporous (Sr-MBG) bioactive glass (PCL) scaffolds by the three-dimensional printing technique, and to explore the effect of these scaffolds on MC3T3-E1 proliferation and osteogenic differentiation, thereby to find out the optimal macropore morphology.METHODS: Sr-MBG/PCL composite scaffolds were fabricated by the three-dimensional printing technique. The angles between fibrous latitudes and longitudes were set to 45°, 60° and 90°. Then the proliferation and alkaline phosphatase activity of MC3T3-E1 cells on the scaffolds were tested.RESULTS AND CONCLUSION: Cell counting kit-8 results showed that MC3T3-E1 cells could proliferate on all the three kinds of scaffolds. The proliferation rate of MC3T3-E1 cells on the 45° Sr-MBG/PCL scaffolds was just slightly higher than that on the 60° and 90° Sr-MBG/PCL scaffolds at days 1 and 4 (P > 0.05), but there was a significant increase at day 7 (P < 0.05). The 45° Sr-MBG/PCL scaffolds exhibited a significant increase in alkaline phosphatase activity of MC3T3-E1 cells compared to the 60° and 90° Sr-MBG/PCL scaffolds at day 14 (P < 0.05), while there was no significant difference among three groups at day 21 (P > 0.05). These results indicate that the 45° Sr-MBG/PCL scaffold is more suitable to promote the proliferation and osteogenic differentiation of the MC3T3 cells than the 60° and 90° Sr-MBG/PCL scaffolds.

Objective:To evaluate the mid- and long-term outcomes of Dynesys hybrid surgery (in some segments act as a non-fusion device, in other segments act as an alternative of rigid fixation in combination with interbody fusion) in the treatment of multi-segmental lumbar degenerative disease (LDD).Methods:The data of 27 patients who received Dynesys hybrid surgery (hybrid group) for the treatment of LDD from May 2011 to September 2016 and completed the follow-up were retrospectively analyzed. Among them, there were 8 males and 19 females; their average age was 59.1±11.9 years (23-78 years). Main diagnosis: 13 cases of lumbar spinal stenosis, 14 cases of lumbar disc herniation; 4 cases of combined lumbar dynamic position instability, 7 cases of combined lumbar spondylolisthesis. There were 15 cases of two-segment disease, 11 cases of three-segment disease, and 1 case of four-segment disease. Segments distribution: 9 cases of L 3-L 5, 6 cases of L 4-S 1, 7 cases of L 3-S 1, 4 cases of L 2-L 5, and 1 case of L 2-S 1. Midline incision was used to exposure, followed by bilateral pedicle screws implantation, and interbody fusion cage with bone grafting were performed at the fusion level. Twenty-seven patients who underwent TLIF+rigid internal fixation during the same period were included as the control group. Clinical outcomes were measured by visual analog scale (VAS) for low back pain and leg pain, and Oswestry disability index (ODI). Radiological outcomes included fusion rate, intervertebral disc height (DH) of surgical segments and the proximal adjacent segment, range of motion (ROM) of non-fusion segments and the proximal adjacent segment. At the same time, the occurrence of complications was observed. Results:Patients of Hybrid group and control group were followed up for an average of 83.8±20.9 months (48-112 months) and 87.3±16.2 months (53-114 months), respectively. Baseline data of the two groups (average follow-up time, age, gender, surgical level, diagnosis) showed no significant difference. The operation time (183.0±27.8 min) and intraoperative blood loss (301.9±178.9 ml) in the hybrid group were significantly lower than those in the control group (operation time t=2.337, P=0.023; blood loss t=2.706, P=0.01). At the final follow-up, the VAS scores of low back pain and leg pain (low back pain t=12.164, P<0.001; leg pain t=20.603, P<0.001), as well as ODI were significantly improved ( t=22.827, P<0.001). A total of 32 segments received TLIF+Dynesys stabilization and 35 segments received Dynesys non-fusion stabilization in the hybrid group, with 28 segments (87.5%) achieved solid fusion at 1-year follow-up. There were 67 fusion segments in the control group, and the fusion rate at 1-year follow-up was 85.1%. DH of non-fusion segments were lower than that before surgery with statistical significance at final follow-up ( t=2.647, P=0.012), while DH of the fusion segments in the hybrid group and the surgical segments in the control group increased compared with that before surgery at the final follow-up. A certain degree of ROM (2.4°±1.5°) was retained of the non-fusion segments at the final follow-up; the ROM of proximal adjacent segments of non-fused segments was significantly smaller than that of proximal adjacent segments of fused segments ( t=2.126, P=0.044). In the hybrid group, screw loosening occurred in 4 patients (8 screws) and adjacent segment degeneration (ASD) occurred in 5 patients. In the control group, screw loosening occurred in 3 patients (6 screws), while ASD occurred in 8 patients. No screw fracture was observed during the follow-up period and no patients received reoperation. Conclusion:Hybrid surgery of Dynesys stabilization combined with interbody fusion is a safe and effective method for the treatment of multi-segmental LDD. Compared with multi-segmental fusion, this lumbar hybrid surgery has the advantages of less trauma and retaining partial segmental ROM.

Objective A finite element analysis was conducted on the biomechanics of the locking plate and intramedullary nail fixation for the treatment of distal tibial fractures,and the resuhs were verified combined with clinical cases,so as to provide references for clinical treatment.Methods (1) Finite element analysis:the three-dimensional CT data of the lower limbs of a healthy male volunteer were used to establish a finite element model.The internal stress distribution of the tibial plateau was set to 60％ of the total load by intramedullary nail and locking plate respectively,and the tibia end was fixed effectively.400 N axial pressure load which equaled to that of adult knee joint during single axis standing was simulated.The equivalent stress and displacement of the model by different fixations were compared.(2) Clinical verification:a retrospective case control study was performed on the clinical data of 37 cases of distal tibia1 fractures treated with internal fixation from June 2015 to December 2016,including 17 cases in intramedullary nail group and 20 in locking plate group.The operation time,intraoperative blood loss,postoperative fracture healing time,and postoperative Johner-Wruhs score of patients were recorded for comprehensive assessment of recovery.Results (1) The finite element analysis results:the maximum stress value was 5.907 MPa for intramedullary nail and 5.821 MPa for locking plate model (P ＞0.05),respectively.The maximum displacement of intramedullary nail model was 2.313 mm,lower than that of locking plate fixation system (3.854 rmm) (P ＜ 0.05).(2) Clinical verification:the operation time and intraoperative blood loss of intramedullary nail were both lower than those of locking plate [(114.1 ±21.6)minutes):(129.8±21.4)minutes and (152.9 ±64.88)ml:(212.5 ±98.5)ml](P ＜0.05).The average fracture healing time was (17.7 ± 2.8)weeks for intramedullary nail and (20.6 ± 4.1) weeks for locking plate (P ＜ 0.05),respectively.In the intramedullary nail group,the Johner Wruhs score was excellent in 13 cases and good in four cases,with excellent and good rate of 100％,while in the locking plate group,nine cases were excellent,eight were good,and three were fair,with excellent and good rate of 85％ (P ＞ 0.05).Conclusions In terms of biomechanics and clinical effect,intramedullary nail fixation is superior than the medial locking plate fixation for the treatment of the distal tibial fractures.Intramedullary nail fixation can reduce surgical trauma and bone displacement after fixation and promote fracture healing.