Objective To explore the efficacy of Krackow locking loop technique combined with the modified Kessler suture technique in the treatment of acute closed Achilles tendon rupture.Methods From January 2020 to January 2022,162 cases of acute closed Achilles tendon rupture were treated with Krackow locking loop technique combined with the modified Kessler suture technique.The patients were treated with the same postoperative rehabilitation plans.The American Orthopaedic Foot and Ankle Society(AOFAS)hindfoot score and Achilles Tendon Total Rupture Score(ATRS)were collected to evaluate the functions.Results The operation time was 24-40 min(mean,31.9±4.6 min).All incisions healed in one stage without infection or sural nerve injury.Complications occurred in 2 patients,including 1 case of deep venous thrombosis and 1 case of trauma-related re-rupture.The recovery time of ankle flexion and extension motion was4-12 weeks(mean,7.6±1.9 weeks),the recovery time of single-legged heel rise height on the affected side was 10-18 weeks(mean,13.3±1.8 weeks),and the recovery time of fast walking or jogging was 14-26 weeks(mean,19.1±1.8 weeks).The 162 patients was followed up for 14-25 months(mean,19.0 months).The AOFAS hindfoot score increased from(54.4±4.4)points preoperatively to(98.0±4.0)points at the last follow-up(t =-104.402,P =0.000).The ATRS score increased from(52.0±8.3)points preoperatively to(91.2±2.4)points at the last follow-up(t =-62.823,P = 0.000).Conclusions For young and middle-aged patients with acute closed Achilles tendon rupture,Krackow locking loop technique combined with the modified Kessler suture technique can achieve good clinical outcomes.Early functional exercise is required to return to work and life.

Objective To observe the effect of different synovial cell secretions on chondrocytes after LPS-induced inflammation,and to explore the mechanism of two synovial cell secretions causing cartilage damage in the progres-sion of KOA disease.Methods Two kinds of synovial cells were co-cultured at 1∶4 and LPS-induced inflamma-tion.The supernatant and exocrine were extracted,and then the normal and LPS-induced inflammation were extrac-ted.The human cartilage tissue obtained during the operation was isolated and cultured into chondrocytes,which were divided into five groups:the first group was added with FLS secretion,the second group was added with nor-mal FLS secretion,the third group was added with secretion after co-culture of two kinds of synovial cells,the fourth group was added with inflammatory MLS secretion,and the fifth group was added with inflammatory FLS se-cretion.CCK-8 was used to detect the viability of chondrocytes in each group.TNF-α,IL-1β,IL-6 level in the su-pernatant of chondrocytes in each group was detected by ELISA.The protein expression of TLR4,NF-κB,IkK,IκB,ADAMTS5 in chondrocytes of each group was detected by Western blot method.Results CCK-8 showed that the activity of chondrocytes in the three groups of inflammatory secretions decreased compared with the secretions from normal synovial cells(P＜0.05);ELISA showed TNF-α,IL-1 β,IL-6 level in the supernatant of group Ⅲ,Ⅳ and V was higher than that of group Ⅰ and Ⅱ(P＜0.05),TNF-α,IL-1 β,IL-6 level in group Ⅲ was higher than that in group Ⅳ but lower than that in group Ⅴ(P＜0.05).Western blot showed the protein expression of TLR4,NF-κB,IkK,IκB,ADAMTS5 in chondrocytes of group Ⅲ,Ⅳ and Ⅴ was higher than that in group Ⅰ and Ⅱ(P＜0.05),the protein expression of TLR4,NF-κB,IkK,IκB,ADAMTS5 in group Ⅲ was higher than that in group Ⅳbut lower than that in group Ⅴ(P＜0.05).Conclusion Two kinds of synovial cell-derived secretions after LPS-induced inflammation can regulate cartilage TLRs/NF-κB signal pathway,causing cartilage inflammation.The in-flammatory effect of MLS secretion is stronger than that of FLS secretion,but the inflammatory effect of MLS secre-tion under two co-cultures is weaker than that of MLS secretion alone.

Objective:To explore the short-term outcomes of 3D-printing stand-alone artificial vertebral body(AVB)in the surgical procedure of anterior cervical corpectomy and fusion(ACCF).Methods:Following the proposal of IDEAL(idea,development,exploration,assessment,and long-term follow-up)framework,we designed and conducted this single-armed,retrospective cohort study.The patients with cervical spondylotic myelopathy were recruited,and these patients exclusively received the surgical procedure of single-level ACCF in our single center.After the process of corpectomy,the size was tailored using different trials and the most suitable stand-alone AVB was then implanted.This AVB was manufactured by the fashion of 3D-printing.Two pairs of screws were inserted in an inclined way into the adjacent vertebral bodies,to stabilize the AVB.The participants were regularly followed-up after the operation.Their clinical data were thoroughly reviewed.We assessed the neurological status according to Japanese Orthopedic Association(JOA)scale.We determined the fusion based on imaging examination six months after the operation.The recorded clinical data were analyzed using specific software and they presented in suitable styles.Paired t test was employed in comparison analysis.Results:In total,there were eleven patients being recruited eventually.The patients were all followed up over six months after the operation.The mean age of the cohort was(57.2±10.2)years.The mean operation time was(76.1±23.1)min and the median bleeding volume was 150(100,200)mL.The postoperative course was uneventful for all the cases.Dysphagia,emergent hematoma,and deterioration of neurological func-tion did not occur.Mean JOA scores were 13.2±2.2 before the operation and 16.3±0.8 at the final follow-up,which were significantly different(P＜0.001).The mean recovery rate of neurological func-tion was 85.9％.By comparing the imaging examinations postoperatively and six months after the opera-tion,we found that the average subsidence length was(1.2±1.1)mm,and that there was only one ca-ses(9.1％)of the severe subsidence(＞3 mm).We observed significant improvement of cervical lor-dosis after the operation(P=0.013).All the cases obtained solid fusion.Conclusion:3D-printing stand-alone AVB presented favorable short-term outcome in one-level ACCF in this study.The fusion rate of this zero-profile prosthesis was satisfactory and the complication rate was relatively low.

Objective To investigate the satisfaction of patients with Crowe Ⅲ-Ⅳ developmental dysplasia of the hip(DDH)after total hip arthroplasty and the related factors.Methods A retrospective study included 169 patients with Crowe type Ⅲ-Ⅳ DDH who underwent total hip arthroplasty between March 2013 and March 2018.Patients were surveyed through WeChat,covering overall satisfaction with the operation,satisfaction with ten daily functions,and the top five questions per-ceived to have a great impact on daily life.Preoperative and postoperative hip function was evaluated by Harris score.Results One hundred and forty-five questionnaires were received,with a follow-up period ranging from 1 to 5 years with an average of(3.23±1.22)years.Among these patients,118 patients were satisfied with the surgical outcomes,while 27 patients were dissat-isfied,with the overall satisfaction rate of 81.38％(118/145).The top five problems affecting patient life were postoperative hip pain,limb length discrepancy,walking,stair climbing,and squatting.There were no statistical differences in age,sex,body mass index,preoperative Harris scores(P＞0.05).However,the dissatisfied group had lower postoperative Harris scores.Post-operative hip pain and limb length discrepancy were identified as direct factors contributing to postoperative surgical dissatis-faction.Conclusion Total hip arthroplasty for patients with Crowe type Ⅲ-Ⅳ DDH is challenging.Postoperative hip pain(mild or severe)and limb length discrepancy(＞2 cm)are independent risk factors for postoperative dissatisfaction.

Objectives:To investigate the risk factors of cage retropulsion(CR)after posterior lumbar inter-body fusion(PLIF).Methods:Retrospective analysis was made on 17 patients(13 males and 4 females,with an average age of 63.7±9.9 years)who underwent revision surgery due to CR after PLIF in our hospital from September 2017 to September 2021.And the patients were included into the CR group.Another 34 patients without CR were matched in a ratio of 2∶1 according to the same fusion and fixation segments,time of initial surgery(±1 year),gender,and age(±2 years),including 26 males and 8 females,with an average age of 65.2±10.2 years.They were included in the control group.In the CR group,the average number of fixed segments was 1.8±0.8,and the average number of fused segments was 1.5±0.6;The time of CR was 7(0.75-132)months after the first operation;15 patients had single segmental CR and 2 patients had two segmental CR.The lumbar lordosis(LL),pelvic tilt(PT),sacral slope(SS),and pelvic incidence(PI)were measured on full-spine X-ray before operation of the two groups of patients,the disc height(DH)of the diseased segment was mea-sured on lateral lumbar X-ray,and the intervertebral range of motion(ROM)was measured on flexion-exten-sion X-ray.The CT value of lumbar vertebrae was measured in CT examination before operation;The shape of disc was defined through MRI examination.The cage position was measured on X-ray immediately after operation(The ratio of the distance between the marker line of the posterior margin of the cage and the pos-terior upper margin of the lower vertebral body to the length of the upper endplate of the lower vertebra).The paired sample t-test was used for single factor analysis to analyze the data of the two groups,after which,the parameters with statistical significance were analyzed with logistic regression to determine the inde-pendent risk factors of CR.Results:The mean vertebral CT value in the CR group was lower than that in the control group(124.8±39.7 vs 147.7±38.2,P=0.011);The cage position in the CR group was more posterior than that in the control group(0.15±0.09 vs 0.31±0.07,P＜0.001).There was no significant difference between the two groups in LL(40.8°±12.9° vs 42.4°±7.5°,P=0.717),PT(19.6°±7.1° vs 17.1°±6.7°,P=0.356),SS(27.7°±6.5° vs 31.0°±4.3°,P=0.144),PI(44.3°±13.8° vs 44.7°±13.9°,P=0.926),DH(10.1±2.4mm vs 8.8±1.4mm,P=0.066),ROM(4.3°±2.8° vs 4.4°±2.2°,P=0.950),and Pear-shaped intervertebral discs(33.3％vs 21.4％,P=0.40).Logistic regression analysis showed that low vertebral CT value(osteoporosis)(OR=0.975,P=0.043)and cage po-sition(OR=28.393,P=0.003)were the independent risk factors.Conclusions:Osteoporosis and posterior placement of cage are the risk factors for CR after PLIF.

Objectives:To evaluate the biomechanical state of the I4-L5 segment after unilateral laminotomy for bilateral decompression(ULBD)surgery using finite element analysis,providing a theoretical basis for the treatment of lumbar degenerative diseases with ULBD.Methods:Thin-slice CT scan data from the lumbar spine of a healthy volunteer were extracted,and high-fidelity three-dimensional finite element methods were applied to establish normal I4-L5 model,post-ULBD surgery model,and post-lumbar fenestration(LF)surgery model.The L5 vertebral body's lower endplate was fully fixed in all the models,and a 500N axial load was applied at the L4 upper endplate,along with a 10N·m bending moment load in six directions of flexion,ex-tension,left lateral bending,right lateral bending,left rotation,and right rotation.Comparative analysis of the biomechanical characteristics such as intervertebral disc compression height,intervertebral range of motion(ROM),stress distribution within the intervertebral disc,and facet joint pressure was conducted under different loads for the three models.Results:The ROMs under six directions of movements were within the range of the measured results of previous cadaveric studies,verifying that the normal model was valid.Under the 500N axial load,the intervertebral disc compression heights for the normal model,post-ULBD and post-LF surgery models were 0.74mm,0.85mm,and 0.85mm,respectively.With an additional 10N·m bending moment load,the intervertebral ROM in flexion,extension,left lateral bending,right lateral bending,left rotation,and right rotation for the normal model were 6.1°,4.2°,5.1°,4.6°,2.9°,and 2.6°,respectively;for the post-ULBD model,they were 6.5°,4.8°,6.0°,5.2°,3.2°,and 2.9°,respectively;and for the post-LF model,they were 6.4°,4.6°,5.6°,5.1°,3.0°,and 2.8°,respectively.There was no significant difference in the stress dis-tribution within the intervertebral disc for the three models,with the maximum von Mises stress occurring at the outer annulus fibrosus on the compressed side of the disc.The maximum von Mises stress in the inter-vertebral disc for the normal model under flexion,extension,left lateral bending,right lateral bending,left ro-tation,and right rotation was 0.52MPa,0.66MPa,0.81 MPa,0.87MPa,0.46MPa,and 0.40MPa,respectively;for the post-ULBD model,it was 0.64MPa,0.76MPa,1.06MPa,1.13MPa,0.60MPa,and 0.64MPa,respectively;and for the post-LF model,it was 0.65MPa,0.80MPa,1.00MPa,1.06MPa,0.66MPa,and 0.65MPa,respec-tively.Significant facet joint contact pressure was observed under left and right rotation,with the normal mod-el showing contact pressure of 60N and 69N,the post-ULBD model showing 30N and 87N,and the post-LF model showing 79N and 120N.Conclusions:After ULBD surgery,there is an increase in lumbar interverte-bral disc compression height,intervertebral ROM,stress within the intervertebral disc,and facet joint pressure.Compared with LF surgery,ULBD has a smaller impact on the biomechanical stability of the lumbar segment.

Lumbar spinal stenosis(LSS) is a common degenerative spinal disease. Over the past 30 years, under the concept of minimally invasive spine surgery (MISS), spinal endoscopy has seen significant advancements, particularly in endoscopic unilateral laminotomy for bilateral decompression (ULBD). This technique, utilizing a fluid medium and small incision, achieves spinal canal decompression while maintaining spinal stability, resulting in satisfactory clinical outcomes. However, endoscopic spinal decompression surgery still has some complications, such as nerve injury, dural tears, myeloid hypertension, and epidural hematomas. Some scholars have begun exploring robotic endoscopic spinal surgery to reduce complications and improve clinical outcomes. This article provides an overview of the current state of endoscopic treatment for LSS, aiming to equip surgeons with a comprehensive understanding of this surgical approach to deliver better patient care.

The training of orthopedic residents in Taiwan, China includes post graduate year and specialist training, which contain continuous orthopedic specialist training, humanistic training, and holistic education to ensure the high post competency of orthopedic residents. The training process is oriented towards competency and outcome, emphasizing the cultivation of core competencies. Comprehensive quantitative standards have been established to comprehensively evaluate the post competency of residents through theoretical, technical, and clinical work assessments. In this paper, the literature on medical education and resident training in Taiwan was reviewed. The overall training system, assessment requirements, and humanistic training of orthopedic residents in Taiwan were introduced. In addition, the models of training orthopedic specialists were compared between Taiwan and Mainland of China represented by Peking University Medical Department to provide reference for the training program of orthopedic residents.

Objective:To investigate the application effect of the comprehensive innovative teaching model with "3D printed model combined with visual surgical simulation" as the core in the clinical teaching of extremity bone defects.Methods:The physicians who participated in the clinical management of patients with extremity bone defects in Department of Orthopedics, Peking University Third Hospital, from March 2019 to December 2021 were selected as subjects and were divided into standardized training group with 52 physicians and refresher physician group with 58 physicians. Teaching and training was performed for the special disease of extremity bone defects, including basic knowledge teaching, dressing change for infected wounds, multidisciplinary discussion, digital surgical simulation, and practical surgical operation. The assessment indices for teaching quality included the assessment of theoretical knowledge and clinical skills, the objective evaluation of the clinical ability of patient management, and an investigation of the degree of satisfaction. SPSS 22.0 was used for the t-test and the chi-square test. Results:After training, both groups had significant increases in the assessment scores of theoretical knowledge [(32.4±6.7）and (42.2±3.8)] and clinical practice skills [(19.6±2.0), (20.8±2.2), (20.5±2.5), (21.5±2.3)]( P<0.05). After training, the standardized training group had significant increases in the scores of six objective evaluation indicators [(8.3±0.8) vs. (6.9±1.1), (7.4±0.7) vs. (6.3±1.5), (7.2±1.3) vs. (5.0±1.4), (7.9±1.2) vs. (4.0±1.5), (8.4±0.8) vs. (6.4±1.6), (40.3±2.6) vs. (28.6±2.4)]( P<0.01), while the refresher physician group had significant improvements in four aspects, i.e., the understanding of extremity bone defects [(8.1±0.9) vs. (7.2±1.1)], the self-confidence in facing complex extremity bone defects [(8.1±1.2) vs. (6.6±0.9)], spatial thinking ability in repair surgery for bone defects [(8.6±0.8) vs. (7.3±0.9)], and overall clinical performance in actual management of patients with bone defects [(41.4±2.3) vs. (37.3±1.8)] ( P<0.01). The satisfaction score for this comprehensive innovative teaching model was (95.3±3.2) points in the standardized training group and (94.8±2.8) points in the refresher physician group. Conclusions:The comprehensive innovative teaching model with "3D printed model combined with visual surgical simulation" as the core can significantly improve the basic knowledge and clinical skills of physicians in a short period of time and meet the needs for learning surgical techniques and advanced diagnosis and treatment concepts among refresher physicians.

Objective:To explore the correlation between mechanical complications and paraspinal muscle degeneration following posterior single-segment osteotomy corrective surgery for chronic osteoporotic vertebral compression fractures (OVCF).Methods:A retrospective analysis was conducted on 80 patients who underwent surgery between January 2008 and January 2021 at Peking University Third Hospital. These patients, who developed kyphotic deformity following OVCF, included 17 males and 63 females with a mean age of 63.21±8.07 years (range, 47-77 years). Postoperative mechanical complications included proximal junctional kyphosis (PJK), screw loosening, adjacent segment degeneration (ASD), and distal junctional kyphosis or failure. Patients were compared based on the occurrence of mechanical complications in relation to fat infiltration (FI), relative gross cross-sectional area (rGCSA), and relative functional cross-sectional area (rFCSA) of the paraspinal muscles. Binary logistic regression analysis was used to identify risk factors for postoperative complications.Results:Among the 80 patients, 19 developed PJK, while 61 did not. The PJK group exhibited significantly higher paraspinal muscle FI (0.44±0.05) compared to the non-PJK group (0.38±0.10, P<0.05). Screw loosening occurred in 7 cases, with 73 cases remaining stable. Those with screw loosening demonstrated higher paraspinal muscle FI (0.47±0.05) than those without (0.38±0.09, P<0.05). Thirty patients experienced ASD, while 50 did not. The ASD group had higher paraspinal muscle FI (0.45±0.07) and lower rFCSA (0.09±0.03) compared to the non-ASD group (0.36±0.10 and 0.13±0.06, respectively, P<0.05). Logistic regression analysis indicated that paraspinal muscle FI and rFCSA were not independent risk factors for developing ASD. Twenty-three patients experienced distal junctional kyphosis or failure, while 57 did not; those with complications exhibited higher paraspinal muscle FI (0.48±0.08) and lower rGCSA (0.16±0.04) and rFCSA (0.09±0.03) compared to those without complications (0.37±0.09, 0.20±0.09, and 0.13±0.06, respectively, P<0.05). Logistic regression analysis suggested that paraspinal muscle FI, rGCSA, and rFCSA were not independent risk factors for developing distal junctional kyphosis or failure. Conclusion:Mechanical complications following corrective surgery for chronic OVCF-related kyphosis may be associated with increased paraspinal muscle FI. Additionally, the occurrence of ASD and distal junctional kyphosis or failure may correlate with reduced paraspinal muscle rFCSA