Knee osteoarthritis accelerates amyloid beta deposition and neurodegeneration in a mouse model of Alzheimer's disease.

Knee osteoarthritis (OA) is characterized by knee cartilage degeneration and secondary bone hyperplasia, resulting in pain, stiffness, and gait disturbance. The relationship between knee OA and neurodegenerative diseases is still unclear. This study used an Alzheimer's disease (AD) mouse model to observe whether osteoarthritis accelerates dementia progression by analyzing brain histology and neuroinflammation. Knee OA was induced by destabilizing the medial meniscus (DMM) in control (WT) and AD (5xFAD) mice before pathological symptoms. Mouse knee joints were scanned with a micro-CT scanner. A sham operation was used as control. Motor and cognitive abilities were tested after OA induction. Neurodegeneration, ß-amyloid plaque formation, and neuroinflammation were analyzed by immunostaining, Western blotting, and RT-PCR in brain tissues. Compared with sham controls, OA in AD mice increased inflammatory cytokine levels in brain tissues. Furthermore, OA significantly increased ß-amyloid deposition and neuronal loss in AD mice compared to sham controls. In conclusion, knee OA accelerated amyloid plaque deposition and neurodegeneration in AD-OA mice, suggesting that OA is a risk factor for AD.

Three-dimensional morphologic features of Asian atypical femur and clinical implications of cephalomedullary nail fixation: Computational measurement at actual size.

PURPOSE: (1) To analyze three-dimensional (3D) morphologic features of atypical femur fracture at actual size without projection error; and (2) to provide clinical implications of cephalomedullary nail (CMN) fixation by separating the medullary canal and the cortex. MATERIALS AND METHODS: Fifty-nine atypical femurs (opposite non-fractured femurs) were reconstructed as 3D models with medullary canal by importing CT data into Mimics® software. A reference line was drawn from the tip of the greater trochanter to the center of the intercondylar notch and used for classifying bowing grade according to the centerline of medulla. Proximal and distal straight lines (length of 60 mm, diameter of 1 mm) were placed in the centerline of medulla. Acute angles between the two straight lines were measured as lateral and anterior bowing. The acute angle by straight line and reference line was measured as proximal and distal bowing in both AP and lateral view. The diameter of curve (DOC) of medulla along the posterior border was measured. RESULTS: The anterior bowing of all femur on lateral view was an average of 13.82° (range, 6.2°-31.1°, SD 3.91), and the values of proximal and distal anterior bowing were an average of 7.82° (range, 2.7°-14.3°, SD 2.23) and 6.0° (range, 2.2°-16.8°, SD 2.31), respectively. The lateral bowing of all femur on AP view was an average of 5.49° (range, 0.1°-17.3°, SD 4.48), and the values of proximal and distal anterior bowing were an average of 3.64° (range, 0.1°-11.3°, SD 2.70) and 2.48° (range, 0-7.4°, SD 1.98), respectively. The medullary canal was changed to be straightened and more bowed anteriorly. Concerning the lateral bowing grade of entire diaphysis, it was grade -I for 15 femurs, grade 0 for 21 femurs, grade I for nine femurs, grade II for five femurs, and grade III for nine femurs. Regarding anterior bowing grade, it was grade II for 14 femurs and grade III for 45 femurs. The average diameter of medullary canal was 1276.3 ± 232.25 mm. CONCLUSION: Asian atypical femur had three morphologic features: (1) straightened medullary canal, (2) positive values of lateral bowing, and (3) significantly increased ante-curvature of medullary canal. Considering that conventional CMN had about 4° of mediolateral angle, the disparity between implant and medullary canal might be clear. Thus, new nail design for Asian atypical femur that could increase the radius of curve (ROC) but decrease the mediolateral angle needs to be introduced.

Cortical Trajectory Screw Fixation in Lumbar Spine Surgery: A Review of the Existing Literature.

Posterior lumbar fusion is a safe and effective surgical method for diseases, such as lumbar stenosis, spondylolisthesis, lumbar instability, spinal deformity, and tumor. Pedicle screw (PS) fixation was first introduced by Bouche and has been adopted as the gold standard for posterior lumbar fusion. Santoni and colleagues introduced a new methodological screw insertion technique that uses a cortical bone trajectory (CBT), described as that from a medial to lateral path in the transverse axial plane and caudal to the cephalad path in the sagittal plane through the pedicle for maximum contact of the screw with the cortical bone. Owing to the lower invasiveness, superior cortical bone contact, and reduced neurovascular injury incidence, the CBT technique has been widely used in posterior lumbar fusion; however, these advantages have not been proven in clinical/radiological and biomechanical studies. We designed the present study to review the existing evidence and evaluate the merit of CBT screw fixation. Six electronic databases were searched for relevant articles published in August 2020 using the search terms "cortical bone trajectory," "CBT spine," "CBT fixation," "cortical pedicle screws," and "cortical screws." Studies were analyzed and divided into the following groups: "biomechanics investigation," "surgical technique," and "clinical/radiological studies." Most studies compared CBT and PS fixation, and the CBT screw fixation method showed better or similar outcomes.

Can the cortical bone trajectory screw technique be an alternative method to the pedicle screw in posterior lumbar fusion? A systematic review and metaanalysis.

OBJECTIVE: The aim of this study was to verify the practicability of the cortical bone trajectory (CBT) method by comparing the clinical outcomes including the complications between the CBT method and pedicle screws (PSs). METHODS: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), web of Science, and SCOPUS electronic databases were searched for relevant articles published through March 2021 that compared the outcomes of the CBT and PSs. The data search, extraction, analysis, and quality assessment were performed according to the Cochrane Collaboration guidelines. The clinical and radiological outcomes of both techniques were evaluated using various outcome measures. RESULTS: Sixteen studies with a total of 1173 patients were included in the study. The outcomes in the meta-analysis indicated that the use of CBT fixation showed better results for overall complications (P < 0.0001), symptomatic adjacent segment disease (sASD) (P = 0.007), superior facet joint violation (SFJV) rate (P = 0.007), operating time (P = 0.007), intraoperative blood loss (P < 0.00001), incision length (P = 0.002), length of hospital stay (P = 0.0006), and revision rates (P = 0.02). However, there were no statistically significant differences in fusion rates or detailed complications including hardware complications, wound infections (all P > 0.05) between the CBT method and PS fixation groups. CONCLUSIONS: The present study revealed that the CBT method was associated with higher functional recovery, lower surgical morbidity rates, lower revision rates, and lower overall complication rates including sASD and SFJV rates. However, both the CBT method and PSs had similar fusion rates, complications including hardware complications (screw malposition, screw loosening, and screw pullout) and wound infections. Thus, the CBT method did not outperform the PSs in all aspects. Therefore, it is recommended to select a surgical method in consideration of the patient's bone mineral density, the condition of the pars interarticularis, or the skill level of the surgeon. Prognostic evaluation through long-term follow-up is required, and more high-quality randomized controlled trials are required to verify and strengthen our results. LEVEL OF EVIDENCE: Level III, Therapeutic Study.

Comparison of anterior-only versus combined anterior and posterior fusion for unstable subaxial cervical injuries: a meta-analysis of biomechanical and clinical studies.

OBJECTIVE: The purpose of the present study was to perform a meta-analysis comparing biomechanical and clinical outcomes between anterior-only and combined anterior and posterior fusions to determine which method of cervical fusion yielded better results for unstable cervical injuries. METHODS: The MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Web of Science and SCOPUS electronic databases were searched for relevant articles published through 2000-2019 that compared the biomechanical and clinical outcomes of anterior-only and combined anterior and posterior fusion for unstable cervical fracture. RESULTS: Eight biomechanical and four clinical studies were included in the analysis. There were significant biomechanical differences between the groups with respect to flexion-extension, axial rotation and lateral bending. Combined fusion provided better biomechanical stability for unstable cervical injuries than anterior-only fusion, regardless of the number of corpectomies or the presence of a posterior column injury. However, despite significant biomechanical differences, there were no significant differences in clinical outcomes, such as the degree of neurologic improvement and complications between the two groups. CONCLUSION: Anterior-only and combined anterior and posterior fusions for unstable subaxial cervical injuries can both restore cervical stability. Although combined fusion might have some advantages in terms of stability biomechanically, there were no significant differences in clinical outcomes, such as the degree of neurologic improvement and perioperative complications. Therefore, rather than the routine use of combined fusion for unstable cervical injuries, the selective use of anterior-only or combined fusion according to the type of injury is recommended.

Biomechanical comparison of single-bundle versus double-bundle anterior cruciate ligament reconstruction: a meta-analysis.

BACKGROUND: Of the many issues regarding surgical techniques related to anterior cruciate ligament reconstruction (ACLR), single-bundle (SB) or double-bundle (DB) ACLR is one of the most debated topics. However, it is unclear which of the techniques yields better outcomes after ACLR for ACL injury. The purpose of this meta-analysis was to compare the benefits of SB versus DB ACLR in terms of biomechanical outcomes. METHODS: The electronic databases MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, Web of Science, and Scopus were searched for relevant articles comparing the outcomes of SB-ACLR versus DB-ACLR that were published until November 2019. RESULTS: Seventeen biomechanical studies were included. The anterior laxity measured using the anterior drawer test showed significantly better results in DB-ACLR when compared with SB-ACLR. In addition, outcomes of the anterior tibial translation test under a simulated pivot shift presented with better results at low flexion and 30° in DB-ACLR, compared with SB-ACLR. However, there were no significant biomechanical differences between the groups in internal rotation. CONCLUSIONS: The present study demonstrated that both techniques for ACLR are associated with restoration of normal knee kinematics. DB-ACLR is superior to SB-ACLR in terms of restoration of anteroposterior stability. However, which technique yields better improvement in internal rotation laxity, and internal rotation laxity under a simulated pivot shift at a specific angle, remains unclear. LEVEL OF EVIDENCE: This is a level II meta-analysis.

The Importance of Early Surgical Decompression for Acute Traumatic Spinal Cord Injury.

BACKGROUND: Traumatic spinal cord injury (SCI) is a tragic event that has a major impact on individuals and society as well as the healthcare system. The purpose of this study was to investigate the strength of association between surgical treatment timing and neurological improvement. METHODS: Fifty-six patients with neurological impairment due to traumatic SCI were included in this study. From January 2013 to June 2017, all their medical records were reviewed. Initially, to identify the factors affecting the recovery of neurological deficit after an acute SCI, we performed univariate logistic regression analyses for various variables. Then, we performed a multivariate logistic regression analysis for variables that showed a p-value of < 0.2 in the univariate analyses. The Hosmer-Lemeshow test was used to determine the goodness of fit for the multivariate logistic regression model. RESULTS: In the univariate analysis on the strength of associations between various factors and neurological improvement, the following factors had a p-value of < 0.2: surgical timing (early, < 8 hours; late, 8-24 hours; p = 0.033), completeness of SCI (complete/incomplete; p = 0.033), and smoking (p = 0.095). In the multivariate analysis, only two variables were significant: surgical timing (odds ratio [OR], 0.128; p = 0.004) and completeness of SCI (OR, 9.611; p = 0.009). CONCLUSIONS: Early surgical decompression within 8 hours after traumatic SCI appeared to improve neurological recovery. Furthermore, incomplete SCI was more closely related to favorable neurological improvement than complete SCI. Therefore, we recommend early decompression as an effective treatment for traumatic SCI.

Acute lumbosacral hemorrhagic ganglion cyst after transforaminal epidural steroid injection.

Epidural steroid injection is one of the most commonly used non-surgical treatments for degenerative lumbar vertebral disease. Its use has increased as degenerative lumbar vertebral disease has increased in frequency. Concomitant complications are being reported more often. In this report, we report a rare case of iatrogenic hemorrhagic cyst following epidural steroid injection. The patient underwent operative treatment with complete resolution of his symptoms.

A Comparison of Results after Anterior Cruciate Ligament Reconstruction in over 40 and under 40 Years of Age: A Meta-Analysis.

PURPOSE: Anterior cruciate ligament (ACL) injury is one of the most common injuries that occur in the knee, and ACL reconstruction (ACLR) is commonly performed for preventing aggravation of degenerative changes and restoring of knee stability in young, athletic patients. This meta-analysis has a purpose of evaluating the clinical and arthrometrical outcomes of ACLR in a group of middle age patients (40 years and older) and comparing with patients under 40 years of age. METHODS: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Web of Science, and SCOPUS electronic databases were searched for relevant articles comparing the outcomes of ACLR between younger and older than 40 years of age until December 2016. Data searching, extraction, analysis, and quality assessment were performed based on the Cochrane Collaboration guidelines. Clinical outcomes were evaluated and compared between groups. The results were presented as mean difference for continuous outcomes with 95% confidence intervals whereas risk ratio for binary outcomes. RESULTS: Seven studies were included in the meta-analysis. Based on International Knee Documentation Committee classification, side-to-side difference, Tegner activity score, Lysholm knee score, there were no significant clinical and mechanical differences between the groups. CONCLUSIONS: This meta-analysis confirmed that after ACLR, middle age (＞40 years) and young age (＜40 years) patients did not present with significant difference in clinical and arthrometric results.

Effect of oleanolic acid on the activity, secretion and gene expression of matrix metalloproteinase-3 in articular chondrocytes in vitro and the production of matrix metalloproteinase-3 in vivo.

In the present study, we tried to examine whether oleanolic acid regulates the activity, secretion and gene expression of matrix metalloproteinase-3 (MMP-3) in primary cultured rabbit articular chondrocytes, as well as the production of MMP-3 in the knee joint of rat to evaluate the potential chondroprotective effect of oleanolic acid. Rabbit articular chondrocytes were cultured in a monolayer, and reverse transcription-polymerase chain reaction (RT-PCR) was used to measure interleukin-1ß (IL-1ß)-induced gene expression of MMP-3, MMP-1, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS-4), ADAMTS-5 and type II collagen. In rabbit articular chondrocytes, the effects of oleanolic acid on IL-1ß-induced secretion and proteolytic activity of MMP-3 were investigated using western blot analysis and casein zymography, respectively. The effect of oleanolic acid on in vivo MMP-3 protein production was also examined, after intra-articular injection to the knee joint of rat. The results were as follows: (1) oleanolic acid inhibited the gene expression of MMP-3, MMP-1, MMP-13, ADAMTS-4, and ADAMTS-5, but increased the gene expression of type II collagen; (2) oleanolic acid reduced the secretion and proteolytic activity of MMP-3; (3) oleanolic acid suppressed the production of MMP-3 protein in vivo. These results suggest that oleanolic acid can regulate the activity, secretion and gene expression of MMP-3, by directly acting on articular chondrocytes.