Intertrochanteric fractures of the femur are common hip fractures in the elderly. Their treatment goals include reducing incidence of complications, improving quality of life and increasing survival rate for the patients. Compared with traditional internal fixation, hip arthroplasty shows certain advantages in the primary treatment of intertrochanteric fractures of the femur and the revision following failure of internal fixation. It enables patients to do early weight-bearing activities to effectively improve their joint function, and reduces the risk of complications associated with long-term bed rest. However, at present, there has been no unified consensus in the academic community regarding the treatment plan of hip arthroplasty for intertrochanteric fractures of the femur. This paper mainly reviews the research progress in such aspects as indications of hip arthroplasty for primary intertrochanteric fractures of the femur and for revision after failure of internal fixation, anatomical and biomechanical characteristics of the femoral trochanter, principles for selection of types and models of joint prosthesis, key operative techniques like intraoperative fixation of bone fragments and prosthesis implantation, and methods of peri-operative comprehensive assessment.

Objective:To evaluate the value of intraoperative cone beam CT (CBCT) in robot-assisted iliosacral screw fixation for posterior pelvic ring injuries.Methods:The 70 patients' data with posterior pelvic ring injuries treated in Tianjin Hospital from March 2020 to October 2023 were retrospectively analyzed. According to the operation method and whether there was intraoperative CBCT verification, the patients were divided into the robot-assisted iliosacral screw fixation group verified by CBCT with 15 cases (robot+CT group), the simple robot-assisted iliosacral screw fixation group with 25 cases (robot group), the freehand iliosacral screw fixation group verified by CBCT with 10 cases (freehand+CT group), and the freehand iliosacral screw fixation group with 20 cases (freehand group). The operation time, the number of intraoperative fluoroscopies, the frequency of guide needle adjustment of each iliosacral screw, Majeed function score, Matta score, fracture healing time, Gras classification of screw position of the four groups were compared, and the iliosacral screw's perforation site were recorded.Results:All patients were followed up, and the follow-up time was 18.89±4.13 months (range, 12-30 months). There were no statistically significant differences in postoperative fracture Matta score, Majeed score and fracture healing time among the four groups ( P>0.05). Specifically, 26, 45, 15, and 32 iliacsacral screws were inserted in the robot+CT group, the robot group, the freehand+CT group, and the freehand group, respectively. The operation times for these groups were 20.19±1.24, 18.78±1.00, 38.13±2.32, and 37.56±1.80 min, respectively. The number of intraoperative fluoroscopies per screw were 20.50±1.37, 18.47±1.06, 39.80±3.56, and 39.34±1.93, respectively. The guide needle adjustment times were 0.54±0.15, 0.47±0.10, 9.33±1.34, and 8.56±0.86, respectively. Statistically significant differences were observed in the above three indicators among the four groups ( P<0.05). There was no statistically significant difference in Gras classification of screw positions among the four groups ( P>0.05). However, in the CBCT verification group (robot+CT group and freehand+CT group), the Gras classification results were 36 screws in Grade I, 4 in Grade II, 1 in Grade III, and 0 in Grade IV. In contrast, in the non-CBCT verification group (robot group and freehand group), there were 48 screws in Grade I, 17 in Grade II, 11 in Grade III, and 1 in Grade IV, with a statistically significant difference (χ 2=8.945, P=0.030). The screw perforation rate in the CBCT verification group was 2% (1/41), with no perforation observed in the robot+CT verification group, compared to 16% (12/77) in the non-CBCT verification group, showing a statistically significant difference (χ 2=4.716, P=0.030). Among the 13 perforating iliosacral screws, two were located in the anterior slope of the sacrum, while 11 were positioned in the posterior and inferior dangerous triangle area of the sacral vertebral body, and the screws were penetrated into the sacral nerve root channel. Conclusions:Robot-assisted iliosacral screw with short operation time, less fluoroscopies and less guide needle adjustments, the screws can be accurately placed according to the plan, with satisfactory clinical outcomes. The penetration sites of robot-assisted iliosacral screw based on two-dimensional X-ray planning were mostly located in the posterior and inferior of the vertebral body at the pedicle level. Intraoperative CBCT can significantly improve the accuracy of sacroiliac screw placement.

A case of traumatic complete lumbosacral spondylolisthesis combined with unstable pelvic fracture is reported. A 55-year-old male patient was admitted to the hospital 8 h after being hit by a heavy object on the lumbosacral region. Admission diagnosis: (1) traumatic hemorrhagic shock; (2) bilateral pulmonary contusion with pleural effusion, and dislocation of the right 12th costovertebral joint; (3) left renal contusion with subcapsular hematoma; (4) traumatic lumbosacral spondylolisthesis (Meyerding grade V), L 5 lamina fracture, L 2 and L 5 spinous process fractures, left L 3-L 5 transverse process fractures, right L 5 inferior articular process fracture, and L 1-L 3 and L 5 transverse process fractures; (5) lumbosacral Morel-Lavallée lesion; (6) pubic symphysis separation, left sacral wing fracture, and sacroiliac joint dislocation (Young-Burgess APC type III); (7) Multiple incomplete injuries of bilateral lumbosacral nerves, and cauda equina syndrome (Gibbons type Ⅳ). The patient underwent open reduction of pelvic fracture and pubic symphysis separation, closed reduction of sacroiliac joint dislocation and combined internal and external fixation, and open reduction and internal fixation of lumbosacral spondylolisthesis. At the 1-year follow-up after surgery, the pelvis achieved anatomical reduction with good fracture healing, the spinal anatomical alignment returned to normal, and lumbosacral bony fusion was observed, and weakness of both lower limbs and abnormal urodynamics caused by residual lumbosacral nerve injury were observed.

Objective:To evaluate the value of intraoperative cone beam CT (CBCT) in robot-assisted iliosacral screw fixation for posterior pelvic ring injuries.Methods:The 70 patients' data with posterior pelvic ring injuries treated in Tianjin Hospital from March 2020 to October 2023 were retrospectively analyzed. According to the operation method and whether there was intraoperative CBCT verification, the patients were divided into the robot-assisted iliosacral screw fixation group verified by CBCT with 15 cases (robot+CT group), the simple robot-assisted iliosacral screw fixation group with 25 cases (robot group), the freehand iliosacral screw fixation group verified by CBCT with 10 cases (freehand+CT group), and the freehand iliosacral screw fixation group with 20 cases (freehand group). The operation time, the number of intraoperative fluoroscopies, the frequency of guide needle adjustment of each iliosacral screw, Majeed function score, Matta score, fracture healing time, Gras classification of screw position of the four groups were compared, and the iliosacral screw's perforation site were recorded.Results:All patients were followed up, and the follow-up time was 18.89±4.13 months (range, 12-30 months). There were no statistically significant differences in postoperative fracture Matta score, Majeed score and fracture healing time among the four groups ( P>0.05). Specifically, 26, 45, 15, and 32 iliacsacral screws were inserted in the robot+CT group, the robot group, the freehand+CT group, and the freehand group, respectively. The operation times for these groups were 20.19±1.24, 18.78±1.00, 38.13±2.32, and 37.56±1.80 min, respectively. The number of intraoperative fluoroscopies per screw were 20.50±1.37, 18.47±1.06, 39.80±3.56, and 39.34±1.93, respectively. The guide needle adjustment times were 0.54±0.15, 0.47±0.10, 9.33±1.34, and 8.56±0.86, respectively. Statistically significant differences were observed in the above three indicators among the four groups ( P<0.05). There was no statistically significant difference in Gras classification of screw positions among the four groups ( P>0.05). However, in the CBCT verification group (robot+CT group and freehand+CT group), the Gras classification results were 36 screws in Grade I, 4 in Grade II, 1 in Grade III, and 0 in Grade IV. In contrast, in the non-CBCT verification group (robot group and freehand group), there were 48 screws in Grade I, 17 in Grade II, 11 in Grade III, and 1 in Grade IV, with a statistically significant difference (χ 2=8.945, P=0.030). The screw perforation rate in the CBCT verification group was 2% (1/41), with no perforation observed in the robot+CT verification group, compared to 16% (12/77) in the non-CBCT verification group, showing a statistically significant difference (χ 2=4.716, P=0.030). Among the 13 perforating iliosacral screws, two were located in the anterior slope of the sacrum, while 11 were positioned in the posterior and inferior dangerous triangle area of the sacral vertebral body, and the screws were penetrated into the sacral nerve root channel. Conclusions:Robot-assisted iliosacral screw with short operation time, less fluoroscopies and less guide needle adjustments, the screws can be accurately placed according to the plan, with satisfactory clinical outcomes. The penetration sites of robot-assisted iliosacral screw based on two-dimensional X-ray planning were mostly located in the posterior and inferior of the vertebral body at the pedicle level. Intraoperative CBCT can significantly improve the accuracy of sacroiliac screw placement.

A case of traumatic complete lumbosacral spondylolisthesis combined with unstable pelvic fracture is reported. A 55-year-old male patient was admitted to the hospital 8 h after being hit by a heavy object on the lumbosacral region. Admission diagnosis: (1) traumatic hemorrhagic shock; (2) bilateral pulmonary contusion with pleural effusion, and dislocation of the right 12th costovertebral joint; (3) left renal contusion with subcapsular hematoma; (4) traumatic lumbosacral spondylolisthesis (Meyerding grade V), L 5 lamina fracture, L 2 and L 5 spinous process fractures, left L 3-L 5 transverse process fractures, right L 5 inferior articular process fracture, and L 1-L 3 and L 5 transverse process fractures; (5) lumbosacral Morel-Lavallée lesion; (6) pubic symphysis separation, left sacral wing fracture, and sacroiliac joint dislocation (Young-Burgess APC type III); (7) Multiple incomplete injuries of bilateral lumbosacral nerves, and cauda equina syndrome (Gibbons type Ⅳ). The patient underwent open reduction of pelvic fracture and pubic symphysis separation, closed reduction of sacroiliac joint dislocation and combined internal and external fixation, and open reduction and internal fixation of lumbosacral spondylolisthesis. At the 1-year follow-up after surgery, the pelvis achieved anatomical reduction with good fracture healing, the spinal anatomical alignment returned to normal, and lumbosacral bony fusion was observed, and weakness of both lower limbs and abnormal urodynamics caused by residual lumbosacral nerve injury were observed.

Intertrochanteric fractures of the femur are common hip fractures in the elderly. Their treatment goals include reducing incidence of complications, improving quality of life and increasing survival rate for the patients. Compared with traditional internal fixation, hip arthroplasty shows certain advantages in the primary treatment of intertrochanteric fractures of the femur and the revision following failure of internal fixation. It enables patients to do early weight-bearing activities to effectively improve their joint function, and reduces the risk of complications associated with long-term bed rest. However, at present, there has been no unified consensus in the academic community regarding the treatment plan of hip arthroplasty for intertrochanteric fractures of the femur. This paper mainly reviews the research progress in such aspects as indications of hip arthroplasty for primary intertrochanteric fractures of the femur and for revision after failure of internal fixation, anatomical and biomechanical characteristics of the femoral trochanter, principles for selection of types and models of joint prosthesis, key operative techniques like intraoperative fixation of bone fragments and prosthesis implantation, and methods of peri-operative comprehensive assessment.

Objective To establish a fluoroscopic percutaneous vertebral augmentation model in dogs by measuring and analyzing canine spinal anatomy.We also assessed the effectiveness and safety of this modeling method by postoperative radiological analysis.Methods Morphological measurements were taken in six dogs,aged approximately 12～24 months,and the following parameters of the lumbar vertebrae were determined:height of the L1～L7 vertebrae,width of the vertebral base,distance from the upper edge of the intervertebral disc to the narrowest part of the vertebra,distance from the vertical line of the spinous process to the upper edge of the intervertebral disc,and vertical distance from the midpoint of the transverse process to the lower edge of the intervertebral disc.These measurements were obtained to clarify the anatomical characteristics of the canine vertebrae and determine the optimal location,direction,and depth for bone-cement injection.A percutaneous vertebral augmentation model was subsequently established in the L4,L5,and L6 vertebrae of six healthy Beagle dogs,weighing 20～25 kg.The dogs were euthanized 4 weeks post-surgery and examined radiologically.Primary observations included the surgical duration,postoperative distribution of the implanted bone cement,and integrity of the vertebral canal and anterior edge of the vertebrae.Results Anatomical observation of the canine vertebrae revealed that the vertebral height increased gradually from L1～L5 and then decreased from L5～L7.The width of the vertebral base increased consistently from L1～L7.The distance from the vertical line of the spinous process to the upper edge of the intervertebral disc showed an increasing trend from L1～L7(1.9～4.0 mm).The distance between the midpoint of the base of the transverse process and the lower edge of the intervertebral disc increased gradually from L1～L5(4.7～6.9 mm).There was no significant difference in the distance between the midpoint of the base of the transverse process and the lower edge of the intervertebral disc in the L4,L5,and L6 segments among the dogs(P=0.925).The midpoint of the root of the transverse process of the spine was taken as the puncture point,and the insertion direction and horizontal plane were at an angle of 20°～30°,with a head tilt of 5°～15° and a puncture depth of 1.2～1.5 cm.If the puncture was directed towards the caudal side of the vertebra,the angle of the needle tail was 30°～35°,with a penetration depth of 1.5～1.8 cm.This technique allowed the successful construction of a canine vertebral puncture surgical model.A total of 15 canine vertebral puncture surgical models were successfully created,with an average surgery time of 22.7±4.6 min(15～30 min)per vertebral segment.During surgery,one vertebral segment experienced spinal cord injury result ing in paralysis of the hind limbs and bowel and bladder incontinence.Two vertebral cortical bones fractured,but there were no deaths due to anesthesia or infection.Four weeks post-surgery,micro-computed tomography-based three-dimensional reconstructions consistently showed bone cement distributed within the trabecular bone of the canine vertebrae,with newly formed bone tissue enveloping the implanted material.There was no leakage,and no complications such as damage to the vertebral canal or the anterior wall of the vertebrae.Conclusions A safe and reliable canine vertebral augmentation puncture model can be successfully established based on the anatomy of the canine lumbar vertebrae(L4～L6)and using the midpoint of the base of the transverse process as a bony landmark.

BACKGROUND:Intervertebral disc degeneration is clinically considered to be the main cause of low back pain,but due to the unclear pathogenesis of intervertebral disc degeneration,there is still a lack of effective means to delay the progression of the disease.Single-cell RNA sequencing technology can amplify and sequence mRNA at the single-cell level,reveal the gene expression intensity of a single cell,discover different cell subsets in tissues according to the heterogeneity of cells,study the pathogenesis of intervertebral disc degeneration at the molecular level,and provide a new theoretical basis for its early diagnosis and treatment. OBJECTIVE:To introduce the basic principles of single-cell RNA sequencing technology and review the research progress of single-cell RNA sequencing technology in intervertebral disc degeneration in recent years. METHODS:A computer was used to search PubMed,Web of Science,CNKI and WanFang databases for the literature published from 2012 to 2022.Key words were"single-cell RNA sequencing,intervertebral disc degeneration,sequencing Technology"in Chinese and English.Duplicate,poor-quality and irrelevant articles were excluded;a total of 70 articles were eventually included. RESULTS AND CONCLUSION:(1)We identified new cell subsets such as homeostatic chondrocytes,hypertrophy chondrocyte-like nucleus pulposus cells and fibrous nucleus pulposus cells,identified the marker genes and transcription factors of these cell subsets,and described the functions,differentiation paths and cell fate of these cell subsets during the development and progression of intervertebral disc degeneration,and proposed the concept of progenitor nucleus pulposus cells.A cell subpopulation with progenitor nucleus pulposus cells properties was identified and its effectiveness in treating intervertebral disc degeneration was verified in mice.(2)Fibro chondrocyte-like annulus fibrosus cells and annulus fibrosus stem cells with both cartilage and fiber properties were identified,and a new type of composite hydrogel was prepared by combining fibrous cartilage inducers silk fibroin and hyaluronic acid in vitro.Experiments in mice demonstrated that this hydrogel could repair both annulus fibrosus tissue and cartilage matrix,and was remarkably effective in the treatment of intervertebral disc degeneration.(3)Regulatory chondrocytes were found in endplate cartilage.Two distinct fates in the progression of intervertebral disc degeneration were analyzed and the differential genes in the two fates were identified.Intercellular communication analysis indicated that regulatory chondrocytes interact with endothelial cells to promote angiogenesis.(4)Immune cells such as macrophages,T cells,myeloid progenitor cells and neutrophils were identified in the degenerated intervertebral disc tissues,demonstrating the existence of immune response during intervertebral disc degeneration.It was found that apolipoprotein induced the polarization of macrophages M1 and M2 subtypes,and this polarization process affected the activity of progenitor nucleus pulposus cells by amplifying the inflammatory response through the MIF signaling pathway.

BACKGROUND:Hydroxyapatite is the main inorganic component of bone tissue.The polymer has the structure and function of a biomimetic extracellular matrix.The composites of hydroxyapatite and polymer have been widely studied. OBJECTIVE:To summarize the research status of hydroxyapatite composite polymer materials for bone tissue repair. METHODS:The articles collected in PubMed,Web of Science,CNKI and WanFang databases were searched from January 2010 to April 2023.The Chinese and English search terms were"hydroxyapatite,polymer,composites,degradability,bone defect,bone repair".Finally,75 articles were included for review. RESULTS AND CONCLUSION:Polymers often used in composite with hydroxyapatite for bone tissue repair include natural polymers(collagen,chitosan,alginate,serine protein,cellulose,hyaluronic acid,and polyhydroxybutyrate)and synthetic polymers[polylactic acid,polylactic acid-hydroxyacetic acid copolymer,poly(has-lactide),poly(amino acid)and poly(vinyl alcohol)].The mechanical properties and osteoinductivity of hydroxyapatite/polymer composites were improved compared with pure hydroxyapatite.Hydroxyapatite composite with polymers can be made into porous scaffolds,hydrogels,and coatings for bone repair.Hydroxyapatite/polymer composites can accelerate bone reconstruction with a slow release of loaded drugs and cytokines due to their bionic extracellular matrix structure and function.Based on the diversity of causes of bone defects and the fact that bone repair is a complex continuous process involving multiple biological factors and proteins,repair materials with mechanical properties matching bone tissue,degradation processes synchronized with bone repair,and efficient osteogenesis and vascularization need to be further investigated.

Objective:To compare the efficacy of the horizontal plate plus raft screws above the acetabulum and fixation with screws only for acetabular fractures combined with dome impaction in the aged patients.Methods:A retrospective cohort study was conducted to analyze the clinical data of 20 aged patients with acetabular fractures combined with dome impaction, who were admitted to Tianjin hospital between May 2013 and January 2023, including 5 males and 15 females, aged 61-84 years [(72.2±7.3)years]. According to Letournel and Judet classification, 13 patients had anterior column fracture, 5 anterior column fracture combined with posterior transverse fracture and 2 two-column fracture. All the patients underwent open reduction and internal fixation through an anterior approach. Of them, 11 patients were treated with the fixation with the horizonal plate plus raft screws above the acetabulum (plate plus raft screw group) and 9 with the screws only (screw only group). The operative time, intraoperative blood loss, and intraoperative fluoroscopy times were compared between the two groups. The quality of fracture reduction was evaluated with the Matta′s radiographic criteria at 3 days after surgery and the function of the hip joint was assessed with Merle D′Aubigné and Postel scoring system at 3 months after surgery and at the last follow-up as well as the excellent and good rate at te last follow-up. The occurrence of postoperative complications was observed.Results:All the patients were followed up for 6-18 months [(13.1±3.1)months]. There were no significant differences in the operative time, intraoperative blood loss or intraoperative fluoroscopy times between the two groups ( P>0.05). According to the Matta′s radiographic criteria at 3 days after surgery, patients with anatomical reduction and satisfactory reduction accounted 6 and 5 in the plate plus raft screw group, compared to 5 and 4 respectively in the screw only group ( P>0.05). The values of Merle D′Aubigné and Postel score at 3 months after surgery and at the last follow-up were (14.0±2.4)points and (15.8±2.2)points in the plate plus raft screw group, which were higher than those in the screw only group [(11.0±2.6)points and (13.0±3.1)points] ( P<0.01). The values of Merle D′Aubigné and Postel score at the last follow-up of both groups were further enhanced from those at 3 months after surgery ( P<0.01). At the last follow-up, 3 patients were rated excellent, 6 good, 1 fair and 1 poor in the plate plus raft screw group, with an excellent and good rate of 81.8%, while in the screw only group, 3 were rated good, 2 fair and 4 poor, with an excellent and good rate of 33.3% ( P<0.05). One patient in the plate plus raft screw group and 5 in the screw only group had displacement of the dome impaction fragment combined with traumatic arthritis after surgery ( P<0.05). Conclusion:For acetabular fractures combined with dome impaction in the aged patients, the horizontal plate plus raft screw above the acetabulum can effectively improve the function restoration of the hip joint and reduce the occurrence of the displacement of the dome impaction fragment and traumatic arthritis after surgery compared to the fixation with screws only.