BACKGROUND:Atlantoaxial fusion is currently the main surgical treatment of atlantoaxial dislocation, but the premise is at the expense of atlantoaxial range of motion, especial y the rotation motion. Restricted non-fusion fixation is a method that can maintain the atlantoaxial stability, while retain the atlantoaxial range of motion. Further research should be performed to compare the biomechanical characteristics between the two methods. OBJECTIVE:To develop a three-dimensional finite element model of atlantoaxial instability, compare and determine the biomechanical properties of posterior atlantoaxial restricted non-fusion fixation system and posterior atlantoaxial screw-rod fixation system. METHODS:A verified intact finite element upper cervical (C0-C3) model was established and analyzed by Simpleware 3.0, Geomagic 8.0, Hypermesh 10.0, Abaqus 6.9, and Rhino 4.0 softwares based on the CT data col ected from a 31-year-old healthy male volunteer. The moment couple of 1.5 N?m was loaded, which made the model movement in flexion-extension, lateral bending, and rotating direction, respectively. The range of motion was recorded and compared with the in vitro biomechanical experimental data to verify the effectiveness of the model. The ranges of motion of the posterior atlantoaxial restricted non-fusion fixation system model and the posterior atlantoaxial screw-rod fixation system model were analyzed using the finite element method under flexion, extension, lateral bending, and axial rotation;meanwhile, stress nephograms of the posterior atlantoaxial restricted non-fusion fixation system model were observed. RESULTS AND CONCLUSION:(1) There were 206 747 elements and 72 500 nodes in the intact model of upper cervical spine (C0-C3) in this experiment, and the range of motion of intact model validated with the reported cadaveric experimental data. (2) The range of motion of the posterior atlantoaxial restricted non-fusion fixation system group was similar to which of the posterior atlantoaxial screw-rod fixation system group in flexion-extension direction. (3) In lateral bending direction, the range of motion of the posterior atlantoaxial restricted non-fusion fixation system model was obviously limited, respectively. The range of motion of the posterior atlantoaxial restricted non-fusion fixation system model was larger than that of the atlantoaxial dislocation model and basical y same as that of the normal atlantoaxial model. (4) As to the rotating direction, the range of motion of the posterior atlantoaxial restricted non-fusion fixation system mainly disappeared at the atlantoaxial segment;by contrast, a majority of rotating motion was stil retained in the posterior atlantoaxial restricted non-fusion fixation system group. (5) The stress concentration occurred in the contact part between the screw and the connecting rod in posterior atlantoaxial restricted non-fusion fixation system model. (6) Results suggest that posterior atlantoaxial restricted non-fusion fixation system is effective and useful for atlantoaxial fixation. It not only restricted atlantoaxial flexion-extension, but also preserved axial rotation and lateral bending at the atlantoaxial joint.

Objective To observe if subclinical lesion exists during and after tibia lengthening and investigate the repair mechanism of the nerve. MethodsTwenty-three cases(with 42 tibia) were lengthened by traction with the velocity of 1mm/d. The somatosensory evoked potentials (SEP) induced by stimulation of tibial nerve were recorded before operation and 2,3 months and 2 years after operation. The tibia was lengthened for a total of 4～10cm. ResultsAll cases had no significant symptoms except for 1 case with mild symptoms of nerve lesion when his tibia was lengthened for 9.5cm. However, the subclinical lesion was found by SEP record in all the cases, and this lesion could be repaired mostly in 3 months and completely recovered in 2 years. ConclusionThe peripheral nerves have good adaptability to tibia lengthening with a velocity of 1mm/d and the tibia could be lengthened to a great extend as long as there were no clinical symptoms manifestated.

BACKGROUND: Multilevel cervical disc herniation accompanying ossification of posterior longitudinal ligament (OPLL) can seriously hurt the spinal cord. Which way of operative approach is more preferable is still uncertain. Whether one-stage combined anterior and posterior operation can achieve better effects remains unclear.OBJECTIVE: To explore the therapeutic effect of one-stage anterior and posterior operation for the treatment of multilevel cervical disc herniation accompanying OPLLMETHODS: Seventeen patients with multilevel cervical disc herniation and OPLL were treated by one-stage anterior and posterior operation at the Department of Orthopaedics, Tongji Hospital, were selected, including 11 males and 6 females, aged 42-74 years,mean aged 51.5 years. X-ray film, CT or MRI before operation showed the cervical cord was compressed by the multilevel herniated cervical discs or the ossified posterior longitudinal ligament. The stability and fusion of the injured segments were observed by regular postoperative X-ray film.RESULTS AND CONCLUSION: All patients were received a 6-36 months follow-up (24.5 months on average). The postoperative JOA scores were (12.88±2.47) points, which was greater than that of preoperatively [(6.41±1.28) points, P<0.05]. The improvement-rate of the spinal function after 6 months included 5 excellent cases, 7 good cases, and 4 fair cases. The excellent-good rate was 71%. All the patients got completely reduction, and all grafts got fused at 3-4 months after operation. The cervical intervertebral height and lordosis were satisfied maintained and there was no complication related to internal fixation breakage, loosening or displacement. It suggested that one-stage anterior and posterior operation can provide satisfied decompression earlier and rebuild the spinal stability in time, which is a safe and effective surgical intervention for multilevel cervical spondylotic myelopathy accompanying OPLL.

Objective To evaluate the outcome of posterior screw-rod fixation system in reduction and internal fixation of atlantoaxial dislocation. Methods A retrospective study was done on 27 patients with atlantoaxial instability including 18 male and 9 female (at age range of 13-51 years, mean 31 years) from January 2007 to May 2009. There were 11 patients with chronic odontoid fractures, five with isolated bone odontoid, seven with transverse ligament rupture of atlas and four with rheumatoid arthritis. Skeletal reduction was performed in all the patients. The anterior atlantodens interval (ADI)ranged from 8 mm to 15 mm, average 11 mm. All the patients underwent an intraoperative reduction by posterior C1 lateral mass and C2 pedicle screws with rod fixation. According to American Spine Injury Association (ASIA) impairment scale, there were eight patients at grade B, 15 at grade C and four at grade D. Results All patients were followed up for 6-24 months (average 13 months), which showed that the neck symptoms were improved, with bony union. The ADI was reduced to 2-4 mm (average 2.8 mm)postoperatively. Postoperative ASIA scale was grade C in four patients, grade D in 12 and grade E in 11.There were no neurologic or vascular complications occurred, or no failure of the internal fixtors, pseudarthrosis or instability. Conclusion Posterior screw-rod fixation system has advantages of simple procedures, few complications and good results and can be used for intraoperative reduction of atlantoaxial dislocation.

Objective:To analyze the epidemiological characteristics of geriatric acetabular fractures in western China.Methods:A retrospective case series study was made on data of geriatric patients with acetabular fracture hospitalized in 4 grade A hospitals in western China from 2015 to 2020. The investigation content included gender, age, incidence rate, injury mechanism, combined injuries, comorbidities, fracture types and treatment plans.Results:A total of 299 geriatric patients with acetabular fractures were included, including 203 males and 96 females, aged 60-97 years [(68.6±7.6)years]. The mean age of the patients was increased from 67.5 years to 71.1 years. The incidence rate was increased from 36 cases per year to 64 cases per year. The injury mechanism was mainly traffic accidents (42.47%), followed by falls (30.44%). Thoracic injury was the most common type of combined injuries (39.81%). Hypertension was the main comorbidity (28.76%). The most common fracture type was anterior column posterior hemitransverse fracture (31.32%). Of 299 patients, 210 received surgical treatment, with the surgery rate of 70.23%.Conclusions:Geriatric acetabular fracture is characterized by gradually increased age and incidence rate, traffic accidents as the main cause of injury, thoracic injury as the main combined injury, hypertension as the main comorbidity, anterior column posterior hemitransverse fracture as the main fracture type and surgery as the main treatment option.

Osteoporotic proximal humeral fracture (OPHF) is one of the common osteoporotic fractures in the aged, with an incidence only lower than vertebral compression fracture, hip fracture, and distal radius fracture. OPHF, secondary to osteoporosis and characterized by poor bone quality, comminuted fracture pattern, slow healing, and severely impaired shoulder joint function, poses a big challenge to the current clinical diagnosis and treatment. In the field of diagnosis, treatment, and rehabilitation of OPHF, traditional Chinese and Western medicine have accumulated rich experience and evidence from evidence-based medicine and achieved favorable outcomes. However, there is still a lack of guidance from a relevant consensus as to how to integrate the advantages of the two medical systems and achieve the integrated diagnosis and treatment. To promote the diagnosis and treatment of OPHF with integrated traditional Chinese and Western medicine, relevant experts from Orthopedic Expert Committee of Geriatric Branch of Chinese Association of Gerontology and Geriatrics, Youth Osteoporosis Group of Orthopedic Branch of Chinese Medical Association, Osteoporosis Group of Orthopedic Surgeon Branch of Chinese Medical Doctor Association, and Osteoporosis Committee of Shanghai Association of Integrated Traditional Chinese and Western Medicine have been organized to formulate Expert consensus on the diagnosis and treatment of osteoporotic proximal humeral fracture with integrated traditional Chinese and Western medicine ( version 2024) by searching related literatures and based on the evidences from evidence-based medicine. This consensus consists of 13 recommendations about the diagnosis, treatment and rehabilitation of OPHF with integrated traditional Chinese medicine and Western medicine, aimed at standardizing, systematizing, and personalizing the diagnosis and treatment of OPHF with integrated traditional Chinse and Western medicine to improve the patients ′ function.

Periarticular fracture of the shoulder is a common type of fractures in the elderly. Postoperative adverse events such as internal fixation failure, humeral head ischemic necrosis and upper limb dysfunction occur frequently, which seriously endangers the exercise and health of the elderly. Compared with the fracture with normal bone mass, the osteoporotic periarticular fracture of the shoulder is complicated with slow healing and poor rehabilitation, so the clinical management becomes more difficult. At present, there is no targeted guideline or consensus for this type of fracture in China. In such context, experts from Youth Osteoporosis Group of Chinese Orthopedic Association, Orthopedic Expert Committee of Geriatrics Branch of Chinese Association of Gerontology and Geriatrics, Osteoporosis Group of Youth Committee of Chinese Association of Orthopedic Surgeons and Osteoporosis Committee of Shanghai Association of Chinese Integrative Medicine developed the Chinese expert consensus on the diagnosis and treatment of osteoporotic periarticular fracture of the shoulder in the elderly ( version 2023). Nine recommendations were put forward from the aspects of diagnosis, treatment strategies and rehabilitation of osteoporotic periarticular fracture of the shoulder, hoping to promote the standardized, systematic and personalized diagnosis and treatment concept and improve functional outcomes and quality of life in elderly patients with osteoporotic periarticular fracture of the shoulder.