Abstract:[Objective] To compare the clinical efficacy of the 3D printed twistlock guider assisted transverse lengthening sacroiliac screw versus traditional freehand technique in the treatment of unstable pelvic fractures. [Methods] A retrospective study was conducted on 44 patients who received surgical treatment for unstable pelvic fractures in our hospital from July 2020 to July 2022. According to the consequence of doctor-patient communication, 25 patients had the screw placed with 3D printed twistlock guider (the guider group), while the other 19 patients were by the traditional freehand technique (the freehand group). The perioperative period, follow-up and imaging data of the two groups were compared. [Results] The guider group proved significantly superior to the freehand group in terms of operation time [(82.4±20.1) min vs (106.8±22.4) min, P＜0.05] and intraoperative fluoroscopy [(7.2±2.0) times vs (24.9±2.3) times, P＜0.05], despite that the former had significantly greater total incision length than the latter [(16.8±2.5) cm vs (8.1±1.5) cm, P＜0.05]. There were no significant differ- ences in intraoperative blood loss, walking time, incision healing grade and hospital stay between the two groups (P＞0.05). All patients in both groups were followed up for (21.5±3.4) months on an average, and there was no a significant difference in the time to resume full weight-bearing activities between the two groups (P＞0.05). The VAS score significantly decreased (P＜0.05), while Majeed score and Harris score significantly increased in both groups over time postoperatively (P＜0.05), whereas which were not statistically significant between the two groups at any time points accordingly (P＞0.05). Regarding imaging, the postoperative Matta's scales were significantly improved in both groups compared with those before surgery (P＜0.05). Although there was no a significant difference in Matta's grade between the two groups before surgery (P＞0.05), the guider group was significantly superior to the freehand group in Matta's grade postoperatively [excellent/good/fair/poor, (24/1/0/0) vs (14/5/0/0), P＜0.05]. In addition, the guider group was also significantly better than the freehand group in term of the position of implant placed [excellent/good/fair/poor, (23/2/0/0) vs (13/6/0/0), P＜0.05]. By the latest follow-up, fracture union on images was achieved in all patients of both groups without significant adverse imaging findings. [Conclusion] Compared with traditional freehand place- ment, the 3D printed twistlock guider assisted transverse lengthening sacroiliac screw for pelvic unstable fracture is more accurate, with shorter operation time, less fluoroscopy time, and better reduction quality.

Abstract:[Objective] To explore the factors of delaying hip arthroplasty 72 hours after admission for femoral intertrochanteric frac- tures in elderly. [Methods] A retrospective study was conducted on a total of 144 elderly patients who underwent hip arthroplasty combined with internal fixation to reconstruct the greater trochanter for femoral intertrochanteric fracture from October 2018 to February 2022. Ac- cording to whether the patient had operation completed 72 hours after admission, they were divided into delayed group and undelayed group. Univariate comparison and binary multifactor logistic regression analysis were used to search the factors related to delay surgery. [Results] Of 144 patients, 33 had surgical treatment performed within 72 hours after admission (the undelayed group), accounting for 22.9%; while the other 111 got surgical operation beyond 72 hours after admission (the delayed group), accounting for 77.1%. In term of uni- variate comparison, the delayed group was significantly younger than the undelayed group [(82.3±4.8) years vs (84.4±5.6) years, P=0.043], the delayed group had significantly higher proportion than the undelayed group in terms of urinary tract infections [26(23.4%) vs 0(0%), P= 0.002], arrhythmia [24(21.6%) vs 1(3.0%), P=0.013], and lung infection [35(31.5%) vs 2(6.0%), P=0.003]. In addition, the delayed group had significantly higher level of alanine aminotransferase than the undelayed group [(15.1±8.9) IU/L vs (11.8±5.5) IU/L, P=0.044]. Howev- er, there were no significant differences in gender composition, drinking history, smoking history, rate of hypertension, rate of diabetes and ASA classification between the two groups (P＞0.05), no significant differences in blood test indexes, including Hb, HCT, TB, ALB, Crea, GLU, K, Na, CI and Ca between the two groups (P＞0.05), and no significant differences in the results of lung CT, heart ultrasound and cra- niocerebral CT between 2 groups (P＞0.05). As results of multivariate logistic regression analysis, arrhythmia (OR=9.383, 95%CI 1.174~ 75.018, P=0.035), pulmonary infection (OR=7.342, 95%CI 1.539~35.035, P=0.012) were independent risk factors for delaying surgical op- eration 72 hours after admission for femoral intertrochanteric fractures. [Conclusion] In this study, arrhythmia and pulmonary infection are the risk factors for delayed operation intervention 72 hours after admission for femoral intertrochanteric fracture in the elderly.

Abstract:[Objective] To investigate the clinical outcomes of arthroscopic cannulated screw fixation for Garden type III-IV femoral neck fractures in young adults. [Methods] A retrospective study was conducted on 40 young adults who underwent surgical treatment for Garden type III-IV femoral neck fractures in our department from January 2018 to December 2020. According to doctor-patient communi- cation, 18 patients underwent the arthroscopic reduction and fixation with percutaneous cannulated screws (the arthroscopic group), while the other 22 patients underwent traditional open reduction and internal fixation with cannulated screw (the traditional group). The periopera- tive, follow-up and imaging results were compared between the two groups. [Results] All patients in both groups had corresponding surgi- cal procedures performed successfully. Although the arthroscopic group consumed significantly longer operation time than the traditional group [(98.0±7.6) min vs (72.8±6.0) min, P＜0.05], the former proved significantly superior to the latter in terms of incision length [(36.27± 4.3) mm vs (94.7±5.8) mm, P＜0.05], fluoroscopy times [(3.1±0.8) times vs (7.2±1.5) times, P＜0.05], intraoperative blood loss [(38.7±5.6) ml vs (245.5±39.6) ml, P＜0.05] and hospital stay [(7.1±1.2) days vs (9.0±1.8) days, P＜0.05]. All the patients were followed up for a mean of (41.4±10.4) months, and the arthroscopic group resumed full weight-bearing activity significantly earlier than the traditional group [(92.6± 1.8) days vs (106.4±4.3) days, P＜0.05]. The VAS and Harris scores, as well as ranges of motion (ROMs) of hip extension-flexion and hip in- ternal-external rotation significantly improved over time in both groups (P＜0.05). There was no significant difference in VAS scores be- tween the two groups before surgery (P＞0.05), however, the arthroscopic group was significantly better than the traditional group in terms VAS score, Harris score, hip extension-flexion ROM and hip internal-rotation ROM at all corresponding time point after surgery (P＜0.05). Radiographically, there were no significant differences in Garden index, shaft-neck angle and T?nnis hip osteoarthritis grade between the two groups at any time points accordingly (P＞0.05). [Conclusion] The arthroscopic reduction and fixation with cannulated screws for dis-placed femoral neck fracture in young adults achieves manipulations under direct vision, with advantages of less intraoperative bleeding, less surgical trauma, less fluoroscopy times, shorter hospital stay, faster fracture healing, and better hip function recovery after surgery.

Abstract:[Objective] To evaluate the effects of physical exercise on quality of life and clinical manifestations of mild to moderate knee osteoarthritis (KOA). [Methods] A total of 76 patients who visited Outpatients Department of Joint Surgery of our hospital for Kell- gren-Lawrence grade I to II KOA from September 2022 to December 2022 were included in this study. The general data of patients were collected, and the World Health Organization Quality-of-Life Scale (WHOQOL-Brief), as well as HSS, KOOS, WOMAC scores and knee flexion-extension range of motion (ROM) were measured for evaluating the quality of life and clinical manifestations. Univariate compari- son, Pearson correlation analysis and logistic regression analysis were conducted on the data. [Results] Of the 76 patients included into this study, 29 patients fall into the exercise group, accounting for 38.2%, while the remaining 47 patients were classified as the non-exercise group, accounting for 61.8%. The exercise group proved significantly lower than the non-exercise group in terms of BMI [(23.8±1.3) vs (25.0±1.7), P=0.002], as well as incidence of diabetes (62.0% vs 91.8%, P＜0.001), hypertension (75.9% vs 91.8%, P=0.010) and coronary heart disease (65.5% vs 87.2%, P＜0.001), while the former had significantly higher levels of education and personal income than the latter (P＜0.05). However, there were no significant differences between the two groups in age, sex, course of disease, number of knee side in- volved, and imaging K-L grade (P＞0.05). The exercise groups was significantly greater than the non-exercise group in terms of WHOQOLBrief scores, including physical health [(63.8±4.8) vs (54.6±3.4), P＜0.001], mental health [(62.6±5.3) vs (53.7±3.4), P＜0.001], social rela-tions (60.9±5.0) vs (53.6± 3.1), P＜0.001] and the surrounding environment [(61.6±4.5) vs (54.0±4.8), P＜0.001], as well as the HSS score [(74.1±4.2) vs (68.3 ±2.5), P＜0.001], KOOS score [(73.7±4.1) vs (68.4±3.3), P＜0.001] and knee ROM [(139.3±9.2)° vs (129.4±13.3)°, P= 0.001], while the former got significantly lower WOMAC score than the latter [(31.2±5.8) vs (43.3±3.0), P＜0.001]. The WHOQOL-Brief scores were significantly positively correlated with HSS, KOOS and knee ROM (P＜0.05), whereas significantly negatively correlated with WOMAC score (P＜0.05). As results of logistic regression the high social relationship score was a positive factor for exercise participation (OR=0.664, P=0.026), while high WOMAC was a risk factor for non-exercise participation (OR=1.681, P=0.001). [Conclusion] Physical exercise does control BMI, reduce the incidences of chronic diseases, and improve quality of life and clinical manifestations in patients with mild to moderate KOA. There is a correlation between WHOQOL-Brief score and clinical score, and WOMAC score could better reflect the situation of the patients.

Abstract:[Objective] To evaluate the clinical efficacy of Wiltse approach transforaminal lumbar interbody fusion (W-TLIF), by com- parison with the traditional posterior midline approach transforaminal lumbar interbody fusion (TLIF) in the treatment of lumbar spinal ste- nosis. [Methods] A retrospective study was conducted on 40 patients who received TLIFs for lumbar spinal stenosis in our hospital from No- vember 2021 to September 2022. According to doctor-patient communication, 19 patients were treated with W-TLIF, while other 21 pa- tients were treated with traditional TLIF. The clinical and multifidus examination data of the two groups were compared. [Results] All pa- tients in both groups had corresponding surgical procedures performed successfully without significant differences in operation time, total incision length, intraoperative blood loss, postoperative drainage volume, and intraoperative fluoroscopy times between the two groups (P＞ 0.05), while the patients in the W-TLIF group resumed postoperative ambulation significantly earlier than those in the TLIF group [(2.3± 0.8) days vs (4.0±1.1) days, P＜0.05]. With time of the follow-up period lasted for (7.1±0.9) months on a mean, the VAS and ODI scores were significantly decreased in both groups (P＜0.05). The W-TLIF group were significantly better than the TLIF group 6 months after oper- ation in terms of VAS score [(1.0±0.5) vs (2.0±1.0), P=0.013] and ODI socre [(11.6±1.8) vs (16.0±3.7), P＜0.001]. Regarding multifidus de- tection, the lean mutifidus cross sectional area (LMCSA) and motor unit action potential (MUAP) were significantly decreased in both groups 1, 3 and 6 months after operation compared with those before operation (P＜0.05), while the denervated potential ratio (DPR) re- mained unchanged (P＞0.05). Although there were no significant differences in LMCSA and MUAP between the two groups before surgery (P＞0.05), the W-TLIF group was significantly superior to the TLIF group in terms of LMCSA [(510.8±54.9) mm² vs (280.7±32.2) mm² , P＜ 0.05] and MUAP [(504.4±58.1) μV vs (313.7±71.0) μV, P＜0.05] 6 months postoperatively, additionally, the former was also significantly better than the latter in term of DPR at all time points postoperatively accordingly (P＜0.05). [Conclusion] The Wiltse approach TLIF has lower damage to the multifidus muscle than the traditional posterior midline approach TLIF, which does reduce pain and is conducive to early rehabilitation.

Abstract:[Objective] To evaluate the clinical outcomes of lateral transverse incision used for locking plate fixation of displaced calca- neal fractures in the elderly. [Methods] A retrospective study was done on 42 elderly patients (42 feet) who received open reduction and in- ternal fixation with locking plate for intraarticular calcaneal fractures from January 2015 to June 2021. According to doctor-patient commu- nication preoperatively, lateral transverse incision was used in 21 patients, while the traditional L-shaped incision was used in other 21 pa- tients. The perioperative, follow- up and imaging data of the two groups were compared. [Results] All patients in both groups had corre- sponding surgical procedures performed successfully without serious complications. The transverse group proved significantly superior to the L-shaped group in terms of incision length [(8.5±1.5) cm vs (17.3±1.7) cm, P=0.029], intraoperative blood loss [(72.4±10.5) ml vs (96.8± 11.2) ml, P=0.007], incision healing grade [A/B/C, (19/2/0) vs (14/6/1), P=0.048] and hospital stay [(8.0±4.6) days vs (18.0±4.9) days, P= 0.012]. However, the transverse group got significantly greater times of intraoperative fluoroscopy than the L- shaped group [(13.5±2.5) times vs (5.8 ± 2.3) times, P＜0.001]. There was no significant difference in operation time and time to resume walking between the two groups (P＞0.05). The follow- up period lasted for more than 12 months, and there was no a significant difference in time to resume full weight activity between the two groups (P＞0.05). The VAS score for pain decreased significantly (P＜0.05), while AOFAS score and inver- sion- eversion ROM in both groups increased significantly over time (P＜0.05), which were not statistically significant between the two groups at any time points accordingly (P＞0.05). Radiographically, calcaneus length, Bohler angle and Gissane angle significantly increased (P＜0.05), while calcaneus width significantly decreased (P＜0.05) in both groups at 2 days and the last follow-up after surgery compared with those preoperatively. At the corresponding time points, there were no significant differences in the above image measurements between the two groups (P＞0.05). [Conclusion] Compared with the traditional L-shaped incision, the lateral transverse incision has the advantages of less trauma and fewer complications in open reduction and internal fixation of displaced calcaneal fractures in the elderly.

Abstract:[Objective] To evaluate the value of 3D printing technology in open reduction and internal fixation (ORIF) of displaced ace- tabular fractures. [Methods] Clinical data of 32 patients with acetabular fracture admitted from January 2018 to June 2022 were retrospec- tively analyzed. According to the results of doctor-patient communication, 16 patients had ORIF performed by using 3D printing simulation preoperatively (3D group), while the 16 patients received traditional ORIF (traditional group). The perioperative, follow- up and imaging consequences were compared between the two groups. [Results] The 3D group proved significantly superior to the traditional group in terms of operation time [(203.4±47.2) min vs (248.2±72.1) min, P＜0.05], total incision length [(22.8±8.9) cm vs (31.3±12.9) cm, P＜0.05], fluoros- copy times [(7.3±1.8) vs (12.3±3.6) times, P＜0.05], intraoperative blood loss [(587.5±401.9) ml vs (885.0±417.7) ml, P＜0.05], blood transfu- sion volume [(132.8±154.4) ml vs (436.9±546.5) ml, P＜0.05] and ambulation time [(5.8±1.1) days vs (8.4±2.2) days, P＜0.05]. All patients in both groups were followed up for a mean of (23.5±10.1) months, and the 3D group resumed full weight-bearing activity significantly earlier than the traditional group [(89.1±3.8) days vs (94.6±4.9) days, P＜0.05]. The VAS scores, hip flexion-extension and internal-external rota- tion ROM, and Harris scores significantly improved over time in both groups (P＜0.05). The 3D group was significantly better than the tradi- tional group in terms of VAS score [1 month postoperatively, (3.5±1.5) vs (5.3±1.0), P＜0.05; 6 months postoperatively, (1.6±1.4) vs (3.4± 1.3), P＜0.05], Harris score [1 month after surgery, (56.4±5.3) vs (51.1±8.1), P＜0.05; 6 months after surgery, (78.1±5.1) vs (72.8±4.8), P＜ 0.05], nevertheless there were no significant differences between the two groups in hip flexion- extension and internal- external rotation ROM at any matching time points, and VAS and Harris scores at the latest follow-up (P＞0.05). Regarding to imaging, the 3D group was sig- nificantly better than the traditional group in fracture reduction quality (P＜0.05). Although there was no significant difference in fracture healing time between the two groups (P＞0.05), the 3D group was significantly superior to the traditional group in Tonnis grade for hip osteo- arthritis at the latest follow-up (P＜0.05), whereas with no femoral head necrosis in anyone in both groups. [Conclusion] 3D printing assist- ed ORIF of displaced acetabular fractures has the advantages of shortening operation time, decreasing trauma, reducing bleeding and X-ray radiation exposure, improving reduction quality and rapid recovery of hip function with fewer complications.

Abstract:[Objective] To investigate the efficacy of different extracorporeal shock wave therapies (ESWTs) in the treatment of deep, relatively deep and superficial fracture nonunion, and explore relative impacting factors. [Methods] From November 2011 to September 2022, a total 87 patients received ESWTs, including focused ESWT (fESWT) used for deep fracture nonunion, fESWT combined with radial ESWT (rESWT), (f- rWSWT) for relatively deeper nonunion, and rESWT for superficial nonunion. The fracture nonunion healing was ob- served and the related factors affecting the healing rate were analyzed. [Results] No adverse events occurred in 87 patients during treat- ment. At the last follow- up, the deep bone nonunion healed in 24 cases (75.0%), while relatively deeper nonunion healed in 36 cases (78.3%), and superficial nonunion healed in 7 cases (77.8%). There were no statistically significant differences in age, sex, bone nonunion type, clinical healing time and healing rate at different time points on images among the three groups based on treatment methods (P＞ 0.05). According to whether the patients had achieved nonunion healed on images at the last follow-up, the healed group were significantly young- er in age than the non-healed group [(34.3±10.5) years vs (40.5±10.1) years, P=0.042], the healed group got significantly more times of treatment than the non-healed group [(22.6±9.8) times vs (8.3±3.6) time, P=0.011], despite insignificant differences between the two groups in gender, type of bone nonunion and interval between diagnosis and first treatment (P＞0.05). As results of multivariate logistic regression, the age was a negative factor for nonunion healing (OR=0.920, P=0.040), while the treatment times of ESWT was a positive factor for non- union healing (OR=1.125, P=0.004). [Conclusion] The individualized ESWT based on depth of fracture nonunion site, does obtain satisfac- tory curative effect. Treatment times and age are important factors impacting ESWT treatment of fracture nonunion.

Abstract:[Objective] To explore the clinical efficiency of the intraoperative navigation system used in pedicle screw placement for correction of scoliosis. [Methods] A retrospective study was conducted on 40 patients who underwent surgical correction with pedicle screw-rod system for scoliosis in our hospital from July 2015 to July 2018. According to the preoperative doctor-patient communication, 21 patients had the pedicle screws placed assisted by intraoperative three- dimensional real-time navigation system (the navigation group), while the remaining 19 patients had screws placed by the traditional freehand technique (the freehand group). The perioperative, follow-up and imaging data of the two groups were compared. [Results] All patients in both groups had corresponding surgical procedures performed smoothly without serious complications. The navigation group proved significantly superior to the freehand group in terms of accuracy of screw placement [A/B/C/D/E, (221/8/5/0/0) vs (174/19/12/7/0), P＜0.001], operation time [(43.7±12.2) min vs (65.4±19.7) min, P＜0.001], in- traoperative blood loss [(623.2±40.5) ml vs (1024.3±38.3) ml, P＜0.001], a single screw insertion time [(2.2±1.3) min vs (5.1±2.4) min, P＜ 0.001], but there was no significant difference in walking time and hospital stay between the two groups (P＞0.05). As time went during fol- low-up period lasted for 12~24 months, with an average of (18.2±4.6) months, both VAS and ODI scores in both groups significantly de- creased (P＜0.05). At any corresponding time points, there were no significant differences in VAS and ODI scores between the two groups (P＞0.05). There was no complications, such as later deformity aggravation and revision surgery in any patients in both groups. Regarding im- aging, the Cobb angle of main curvature, kyphotic Cobb angle, C₇PL-CSVL and SVA significantly improved in both groups 2 weeks after surgery and at the last follow- up compared with those preoperatively (P＜0.05), which were not statistically significant between the two groups at any time points accordingly (P＞0.05). [Conclusion] Application of the intraoperative real-time 3D navigation system makes pedi- cle screw placement for correction of scoliosis more accurate and rapid, reduces the risk of surgery, and achieve significantly improved clini- cal efficiency.

Abstract:Cartilage degeneration is the core feature of osteoarthritis (OA), while chondrocyte senescence and the related metabolic im- balance are critical reasons for the continuous progression of cartilage degeneration. Acetylation/deacetylation is one of the key mechanisms in mitochondrial quality control (MQC) and is mainly mediated by deacetylase (SIRT). In recent years, it has been found that MQC imbal- ance is closely related to OA chondrocyte senescence and cartilage degeneration, while SIRT1/3 is differentially expressed in normal and OA chondrocytes, and participates in the regulation of MQC imbalance and senescence of OA chondrocytes. This study reviews the regulato- ry role of MQC in OA chondrocytes, mainly from the perspective of SIRT1/3 and cellular senescence, to sort out ideas and potential targets for subsequent studies on OA pathogenesis and therapeutics.

Abstract:Posteromedial process fracture of the talus, also known as Cedell avulsion fracture or Cedell fracture, is extremely rare and prone to be misdiagnosed clinically. This article combines a clinical case report with reviews the literature to provide a reference for clini- cians. The Cedell's fracture was mostly caused by sports injury (61.3%), followed by high-energy injury (38.7%), and missed diagnosis rate was of 64.5% at initial diagnosis. The current treatment methods include mainly open reduction and internal fixation, bone block resection, brace or plaster fixation. Based on current studies, it is not possible to identify the typical traumatic mechanism of Cedell's fracture or sug- gest which treatment option is better.

Abstract:Previous studies have shown that diabetes mellitus, a systemic metabolic disease, is closely related to the prognosis of posteri- or lumbar interbody fusion (PLIF), whereas the specific mechanism remains unclear. Although relevant literatures suggest that diabetic pa- tients have a high incidence of postoperative complications after PLIF, they could also obtain good surgical outcomes by effectively evaluat- ing patients' physical condition and controlling perioperative blood glucose to ensure it stability. The purpose of this article is to summarize the systemic and perioperative complications, as well as other long-term adverse role diabetes on PLIF by reviewing previous articles, to ex- plore and improve the parameters for predicting postoperative complications in diabetes patients, to analyze the mechanisms by which diabe- tes affects prognosis, and to evaluate the effectiveness and safety of PLIF under this condition to provide a reference for clinician.

Abstract:[Objective] To explore the prognostic model of IncRNA for osteosarcoma (OS), and create competing endogenouse RNA (ceRNA) regulatory networks. [Methods] High- throughput sequencing data and corresponding clinical data were downloaded from the TARGET database after R software was used to filter low-abundance genes and collate corresponding clinical information, sequencing data of 85 cases were obtained, and lncRNA and FRGs were extracted. Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Ge- nomes (KEGG) pathway enrichment analysis were conducted and the lncRNA, miRNA and FRGs genes were finally screened by Spearman correlation analysis. [Results] A total of 7 658 lncRNA and 175 FRGs were extracted from the TARGET-OS database and 1 158 lncRNAs were significantly associated with ferroptosis. GO analysis showed that CC mainly involved extracellular matrix, osteogenesis, cell-matrix adhesion and receptor-mediated endocytosis, while BP mainly involved cell-base junction, adhesion plaque, extracellular matrix contain- ing collagen, cell contact front and free ribosome. lncRNA PVT1 was found to have certain binding targets with miRNA (hsa-miR-106a5p, hsa-miR-17-5p, hsa-miR-20a-5p). Further analysis showed that lncRNA PVT1 gene was associated with OS immunity (R=-0.27, P= 0.014). The expressions of PDCD1LG2 and CD27 in high-risk group were lower than those in low-risk group (T-test, P＜0.05). [Conclu- sion] The prognosis model of lncRNA related to ferroptosis has good predictive ability, which provides a basis for optimizing the manage- ment of OS. lncRNA ceRNA networks related to ferroptosis may provide valuable data support for the molecular mechanism of OS occur- rence and development.

Abstract:[Objective] To introduce the surgical technique and preliminary clinical results of percutaneous cannulated screws under navigation for Day typeⅡcrescent fracture dislocation of the pelvis (CFDP). [Methods] From January 2015 to December 2018, 23 patients received abovesaid surgical treatment for Day typeⅡ CFDP. As Mimics 17.0 software was used to plan screws fixation before operation, an orthopedic 3D navigation was used during the operation. After the screw track was determined, the registration of navigation was completed centering on the sacroiliac joint of the affected side to obtain the relative position of the crescent fracture line passing through the sacroiliac joint. Under navigation, sacroiliac screws were used to fix the sacroiliac joint in front of the crescent fracture, and then LC-Ⅱ screws were placed under the navigation posterior to the "teardrop". Subsequently, the CLIC point was used as the entering point to place the second screw parallel to the LC-Ⅱ screw. [Results] All the 23 patients had operation performed successfully without complications such as neuro- vascular injury. The time for LC-II screw placement ranged from 1.8 min to 3.0 min with an average of (2.3±0.3) min. The Majeed functional score significantly increased 6 months postoperatively compared with that preoperatively [(87.3±1.6) vs (18.5±1.1), P＜0.05]. According to Gras classification, the safe screw placement rate was of 95.6% (22/23). In addition, the excellent and good rate of fracture reduction was 91.3% (21/23) based on Matta's imaging criteria. [Conclusion] This percutaneous cannulated screw under navigation for Day type Ⅱ CFDP has the advantages of low radiation exposure, accurate screw placement, satisfactory fracture reduction, and good functional recovery.

Abstract:[Objective] To introduce the surgical technique and preliminary clinical results of a new combined reduction frame for su- pracondylar fractures of the humerus in children. [Methods] A retrospective study was made on 30 children who received closed reduction under the new combined reduction frame and percutaneous internal fixation with Kirschner wire for humeral supracondylar fractures. The patients were placed in the lateral decubitus position with the affected limb and body rested on the new combined reduction frame that at- tached with the operating table to resist the traction force in the opposite direction. After manual reduction of the fracture, its position was temporarily maintained by the forearm weight in suspension with elbow flexion at 90 degrees. As a satisfactory reduction was checked by fluoroscopy, Kirschner wires were percutaneously placed in a cross manner to fix the fracture stably. [Results] All the patients got operation conducted smoothly without complications such as nerve injury, whereas with operation time of (28.0±3.7) min, fluoroscopy of (4.5±0.9) times, intraoperative blood loss of (23.5±6.9) ml and hospital stay of (3.5±0.9) days. A month after operation, all the children got complete fracture healing with excellent and good rate of 98.7% based on Flynn score, and had the implant removed. [Conclusion] Utilizing this new combine reduction frame, fracture reduction and internal fixation do be realized by single-person operation for humeral supracondylar frac- tures in children, which reduces the need for medical staff, declines radiation exposure, shorten the operation time and save cost of patients.

Abstract:[Objective] To introduce the surgical technique and preliminary clinical results of one-stage anteroposterior flat osteotomy for correction of cervical hemivertebra deformity. [Methods] A 7-year girl received the abovesaid operation for congenital C₆ hemivertebra deformity, who had right hemivertebra of C₆ with vertebral artery passing through the transverse foramen. Before surgery a real cervical mod- el was made by 3D printing to design osteotomy. The anterior approach was conducted firstly to cut off part of the vertebral body of C₆ and C₇, so that the corresponding part of C₆ and C₇ was levelled without the need to deal with the right vertebral artery of C₆. The posterior approach was secondarily made to conduct posterior osteotomy of C₆, C₇, and had pedicle screw fixation of C₅~T₁. Finally, the anterior plate fixation was performed again through the anterior approach. [Results] The patient had operation performed successfully without complications such as spinal nerve and vertebral artery injury, while with operation time of 5 hours, and the intraoperative blood loss about 400 ml. The patient's torticollis improved significantly after surgery, with the Cobb angle of the cervical scoliosis improved from 33° before surgery to 5° after sur- gery and well cervical balance on the coronal plane on images and satisfactory placement of internal fixation implants. [Conclusion] This one-stage anteroposterior flat osteotomy achieves satisfactory preliminary clinical outcome for correction of cervical hemivertebra deformity, which does avoid interference of vertebral artery during osteotomy and improve the safety of the surgery.

Abstract:[Objective] To evaluate the clinical outcomes of short-segment pedicle screw fixation (SPSF) combined with vertebroplasty (VP) through Wiltse approach for Genant grade III osteoporotic vertebral compression fractures (Genant III OVCFs). [Methods] A retrospec- tive study was performed on 48 patients who received abovementioned procedures for Genant III OVCFs from April 2019 to June 2020. The clinical and imaging consequences were evaluated. [Results] All the 48 patients were successfully operated on with the average operation time of (72.9±8.1) min, intraoperative blood loss of (52.7±9.5) ml, and the volume of bone cement injected of (6.1±0.4) ml. All the 48 pa- tients were followed up for 12~24 months, with an average of (17.4±4.4) months. Compared with those preoperatively, 7 days postoperative- ly and the latest follow-up the VAS scores [(7.5±0.7), (2.2±0.5), (2.1±0.6), P＜0.05] and ODI score [(82.4±3.1), (28.3±3.0), (26.9±3.3), P＜ 0.05] significantly reduced. Radiographically, the local kyphotic Cobb angle and relative vertebral body height significantly improved 7 days after surgery and at the last follow- up compared with those preoperatively (P＜0.05). [Conclusion] The SPSF combined with VP through Wiltse approach is safe and effective to restore vertebral height, correct kyphotic deformity, strengthen vertebral body, and reestab- lish biomechanical stability for the Genant III OVCFs