The efficacy of oral vitamin D supplements on fusion outcome in patients receiving elective lumbar spinal fusion-a randomized control trial.

BACKGROUND: Previous studies have reported that vitamin D supplement could improve fracture healing, but evidence regarding the role of vitamin D supplements in spinal fusion was limited. Thus, this study aimed to evaluate the effectiveness of oral vitamin D supplements on fusion outcomes in patients undergoing lumbar spinal fusion. METHODS: This randomized, double-blind, parallel-designed, active-control trial included the patients who planned for elective lumbar spinal fusion. Eligible patients were randomly assigned to receive either daily vitamin D3 (cholecalciferol) 800 IU and daily calcium citrate 600 mg (experimental group) or only daily calcium citrate 600 mg (control group). All supplements were given from postoperative day 1 and lasted for 3 months. Primary outcome was postoperative 1-year fusion rate, and secondary outcomes included time to fusion, Oswestry Disability Index (ODI), and visual analogue scale (VAS) for pain. RESULTS: Among the included 34 patients (21 in the experimental group and 13 in the control group), baseline 25-hydroxyvitamin D (25[OHVitD) level was 26.7 (10.4) ng/ml. Preoperative prevalence of vitamin D deficiency and insufficiency were 23.5% and 47.1%, respectively. Postoperative 1-year fusion rate was not significantly different between the two groups (95.2% vs. 84.6%, P = 0.544). The experimental group had significantly shorter time to fusion (Kaplan-Meier estimated: 169 days vs. 185 days [interquartile range: 88-182 days vs. 176-324 days], log-rank test: P = 0.028), lower postoperative 6-month ODI (P < 0.001), and lower postoperative 6-month VAS (P < 0.001) than the control group. Time to fusion was significantly and negatively correlated with preoperative, postoperative 3-month, and 6-month 25(OH)VitD levels (all P < 0.01). CONCLUSION: The patient with vitamin D supplements had shorter time to fusion, better spinal function and less pain after elective spinal fusion. Further research is warranted to identify the patients who can benefit the most from vitamin D supplements and the appropriate dose of vitamin D supplements. TRIAL REGISTRATION: ClinicalTrials.gov, NCT05023122. Registered 20 August 2021. Retrospectively registered, http://clinicaltrials.gov/ct2/show/NCT03793530 .

Surgical stabilization of the ipsilateral scapula and rib fractures using the mirror Judet approach: a preliminary result.

BACKGROUND: We report our preliminary results using a single approach, the mirror Judet approach, for patients with both ipsilateral scapula and multiple rib fractures. METHODS: Five consecutive patients [median age: 56 years (range: 44 ~ 60)] with ipsilateral scapula and multiple rib fractures that met the surgical indications were retrospectively reviewed. A single approach, the mirror Judet approach, was used for surgical stabilization of the scapula and targeted rib fractures. Thoracoscopic surgery was performed first for management of associated lung lesions and marking the targeted rib. All patients received the same rehabilitation protocol and a minimum 12-month follow-up. RESULTS: All surgically-fixed fractures eventually united without malunion. No complaints of intercostal neuralgia, infection, or other complications were seen. The mean range of motion in the injured shoulder returned to at least 90% of the contralateral side range. The mean Disabilities of the Arm, Shoulder, and Hand score at the 12th month was 2.0 (range: 0-7). All patients were able to return to their previous work. CONCLUSION: The mirror Judet approach allows for the surgical stabilization of the ipsilateral scapula and multiple rib fractures using the same approach and provides acceptable functional outcomes in well-selected patients. LEVEL OF EVIDENCE: Level IV.

Gender differences in femoral trochlea morphology.

PURPOSE: This study aimed to analyze the morphology of the anterior femoral condyle using a quantitative three-dimensional reconstruction method. The morphological data were compared between genders. METHODS: Computed tomography scans of femurs were taken from 90 healthy subjects and then reconstructed in 3D modeling software. Coaxial cutting planes were created at 10° increments to measure the lateral and medial anterior condylar heights (LACH and MACH, respectively), lateral and medial trochlear groove widths (LTW and MTW, respectively), and for trochlear groove tracking. The absolute values and normalized data were compared between male and female subjects. The sulcus angle and deepest point of the trochlear groove at each cross-section were also analyzed to determine the differences in the depth of the trochlear groove. RESULTS: The absolute dimensions of LACH, MACH, LTW, and MTW were significantly smaller in the female subjects, by 10.5%, 36.9%, 10.3%, and 11.0%, respectively, than in the males (p < 0.05). After normalization, no significant difference was found in the condylar height between the genders. However, the female subjects had a significantly larger value of approximately 7.9% for the normalized trochlear width. CONCLUSION: Male subjects had greater condylar heights and widths than the female subjects. Although the trajectory of the trochlear groove varied greatly among the subjects, the trochlear groove appeared to be wider and shallower in the female subjects than in the male subjects. These results provide important information for the design of femoral trochlea to fit Asian female patients. LEVEL OF EVIDENCE: III.

Clinical feasibility of the augmented reality computer-assisted spine surgery system for percutaneous vertebroplasty.

PURPOSE: This study aimed to demonstrate that the augmented reality computer-assisted spine surgery (ARCASS) system is clinically feasible for percutaneous vertebroplasty (PVP). METHODS: This prospective case-control study included the patients undergoing PVP under the assistance of the ARCASS system between July 1, 2013, and October 31, 2014. The control group was the age- and gender-matched patients who underwent standard PVP and met the same eligible criteria as the case group. Primary outcome was the frequency of fluoroscopy. Secondary outcomes were the accuracy of bony entry point and operative time. RESULTS: Eighteen patients were included in this study: 9 patients with 11 levels of lesions in the ARCASS group and 9 patients with 10 levels of lesions in the control group. Compared with the control group, the ARCASS group had significantly less frequency of fluoroscopy (6 vs. 18, P < 0.001) and shorter operative time (78 vs. 205 s, P < 0.001) during the process of entry point identification and local anesthesia, which started from the registration of skin entry point at lesion site to the end of bony entry point identification. Regarding accuracy, the ARCASS group had significant greater proportion of 'good' entry point than the control group on lateral views (81.8% vs. 30.0%, P = 0.028) and anteroposterior views (72.7% vs. 20.0%, P = 0.020). CONCLUSION: This study revealed that the ARCASS system was clinically feasible for PVP. The guidance of ARCASS system provided more accurate bony entry point with reduced operative time and unnecessary radiation exposure.

Dual-acting antibacterial porous chitosan film embedded with a photosensitizer.

This study proposes to develop a dual-acting antibacterial film of porous chitosan (Cs) embedded with small molecular compound, which possesses photosensitive characteristics with bactericidal efficacy, to promote the accelerated recovery of infectious wounds. The Cs/small molecular compound (Cs-cpd.2) dressing was prepared using the freeze-drying method. Characterization of the synthesized Cs-cpd.2 indicated that it has high porosity and moisture absorption effect, hence enhancing the absorption of wound exudate. Experimental results showed that Cs-cpd.2 dressing has good bactericidal and bacteriostatic effects on Staphylococcus aureus under visible-light irradiation and has antibacterial effect in the dark. It was also found that the small molecular compound does not have cytotoxicity at a dose of 0-5 µM. Furthermore, Cs-cpd.2 that contained small molecular compound with a concentration of 0.3-1 µM has positive effect on both the cell viability rate and cell proliferation rate of human fibroblast CG1639. Cs-cpd.2 can significantly promote cell proliferation when the small molecular compound and the basic fibroblast growth factor bFGF were added together. Therefore, the proposed Cs-cpd.2 dressing is feasible for photodynamic therapy (PDT) and clinical wound dressing applications.

Anatomic Locking Plate for Displaced Intraarticular Calcaneal Fracture: Design and Application.

Calcaneal fracture can lead to long-term disability and have a considerable economic effect. Most calcaneal fractures are intraarticular fractures involving the posterior facet of the subtalar joint. Treating displaced intraarticular calcaneal fractures is complicated because of the lack of an optimal treatment option. Internal fixation typically involves screw-and-plate implants, which can be unfavorable owing to the lack of an anatomic design and the intraoperative bending required for the plate to contour to the irregular surface of the calcaneus. We assessed the outcomes of 30 patients treated using innovative, anatomically designed calcaneal locking plates and the perceived advantages for surgeons. Postoperative computed tomography images of the affected feet were obtained, and the functional performance was recorded. The mean average Böhler angle had increased significantly from 16.8° ± 14.9° to 28.5° ± 9.4° (p < .001). The mean average maximal fracture gap and maximal step-off in the posterior facet of the subtalar joint in the coronal computed tomography images also decreased significantly from 2.8 ± 3.7 mm to 0.8 ± 1.3 mm (p < .01) and from 3.3 ± 2.8 mm to 0.8 ± 1.2 mm (p < .001), respectively. The mean average American Orthopaedic Foot and Ankle Ankle-Hindfoot scale score was 93.9 ± 7.1 at the final follow-up visit. In addition, the surgical time was reduced because bending the plate was not required and the quality of reduction could be assessed easily by examining the gap between the cortex and the plate. The results were promising, revealing that the anatomic locking plate can be used effectively in the treatment of displaced intraarticular calcaneal fractures using simple reduction techniques with a potentially shortened operating time.

Beneficial effects of bipolar hemiarthroplasty replacement and fosamax in the retrospective cohort study of refracture and mortality of hip fractured patients.

The epidemiological hip fracture leads to a high death rate in the elderly with osteoporosis worldwide. However, the appropriate surgical styles or anti-osteoporotic therapy could prevent these patients with hip fractures from suffering refracture, but the efficacy of such treatment remains elusive for first hip fractured patients. Our retrospective analysis was conducted on 508 hip fracture patients who were enrolled from Show Chwan Memorial Hospital from January 2005 through December 2011 and followed up until the end of 2012. However, bipolar hemiarthroplasty replacement and open reduction internal fixation (ORIF) are treatment options for femoral neck and intertrochanic hip fracture in our study population. Among these patients, 82 suffered 2nd hip fracture (refracture) with femoral neck or intertrochanteric fracture and 39 died after surgical intervention accompanied complications. Kaplan-Meier analysis revealed a better outcome in patients with bipolar hemiarthroplasty replacement or fosamax therapy of hip fractured patients than those with femoral neck/ORIF and intertrochanteric/ORIF or without fosamax therapy. Multivariate cox regression analysis revealed the lowest incidence of refracture and mortality in hip fracture patients with received bipolar hemiarthroplasty replacement surgical intervention (OR=0.732, CI=0.587-0.912; P=0.006). It is therefore concluded that fosamax therapy may improve bone density and increase bone tissue repair to prevent patients with hip fracture from refracture, and bipolar hemiarthroplasty replacement may promote patients who undertake outdoor activities to produce more vitamin D than those who have received ORIF.

Proximal femoral morphology and the relevance to design of anatomically precontoured plates: a study of the Chinese population.

Adequately shaped femoral plate is critical for the fixation of fracture in the pertrochanteric regions. Lateral aspect of greater trochanter is an important region where the proximal femoral plate anchored. However, little is known regarding the morphology of greater trochanter. The objective of this study was to measure main dimensions of greater trochanter and other regions in the proximal end of the femur to provide an anatomical basis for the design of the proximal femoral plate. Anthropometric data on the proximal femur were performed utilizing three-dimensional computational modeling. Computed tomography images of healthy femurs in 53 women and 47 men were contributed to three-dimensional femur modeling. All data were compared between male and female femora. The results showed that mean values for male group were found to be greater in most of measured femoral dimensions. Oppositely, females demonstrated higher neck-shaft angle on anteroposterior view and femoral anteversion angle. The anthropometric data can be used for the anatomical shape design of femoral plates for osteosynthesis of fractures in the trochanteric regions. A distinct plate design may be necessary to accommodate differences between the genders.

Mechanical behaviors of titanium, nickel-titanium, and stainless elastic intramedullary nail in fixation of tibial diaphyseal fractures.

INTRODUCTION: Elastic nails have been widely used in the diaphyseal fracture fixation of long bones in adolescents. However, high complication rates have been reported in cases involving weights exceeding 55 kg. The existing nails are fabricated with different metals in clinical settings; however, the effect of the materials on the mechanical responses of the fractured bone remains unclear. Hence, the present study is conducted to compare the mechanical responses of typically used metals, namely titanium, stainless, and nickel-titanium, for elastic nails in the fixation of tibial diaphyseal fractures. MATERIAL AND METHODS: A sawbone tube is used to determine the contact force, which is developed after constraining the nail inside the narrow canal using different nail materials. Furthermore, a finite element (FE) model of the tibial diaphyseal fracture is developed to predict the fracture gap deformation based on different nail materials under axial compression and bending loads. The push-out force in the FE simulation is compared with that of a case without an end cap. RESULTS: In the sawbone tube, the results indicate that the contact force developed by the titanium nail is significantly higher than those developed by stainless and nickel-titanium nails. The contact forces developed by the titanium, stainless steel, and nickel- titanium nails are 385 (SD 34), 358 (SD 49), and 258 (SD 42) N, respectively. In the FE simulation, the titanium nail yields the highest push-out force when an end cap is not used, and the push-out forces in axial compression are 201, 183, and 87 N in the titanium, stainless, and nickel-titanium nails under axial compression, respectively. By contrast, the stainless nail yields the smallest gap deformation when an end cap is used. CONCLUSION: Results of the present study show that the end cap is an important factor affecting the mechanical responses of nails fabricated using different materials. Titanium nails are preferred when an end cap is not used, whereas stainless nails are preferred when an end cap is used.

Enriched Peripheral Blood-Derived Mononuclear Cells for Treating Knee Osteoarthritis.

Osteoarthritis (OA) is a common chronic skeletal disease in the elderly. There is no effective therapy to reverse disease severity and knee OA (KOA) progression, particularly at the late stage. This study aims to examine the effect of peripheral blood-derived mononuclear cells (PBMNCs) on pain and motor function rescue in patients with Kellgren-Lawrence (KL) grade II to IV KOA. Participants received one intra-articular (IA) injection of autologous PBMNCs. The mononuclear cells were isolated from peripheral blood, enriched by a specialized medium (MoFi medium), and separated by Ficoll-Paque solution. The isolated and enriched PBMNCs could differentiate into M1 and M2 macrophages in vitro. The in vivo anti-inflammatory effect of the PBMNCs was similar to that of bone marrow mesenchymal stem cells, evaluated by complete Freund's adjuvant-induced arthritis in rodents. A single-arm and open-label pilot study showed that patients' knee pain and motor dysfunction were significantly attenuated after the cell transplantation, assessed by visual analogue scale (VAS) and Knee injury and Osteoarthritis Outcome Score (KOOS) at 6 and 12 months post-treatment. Notably, the therapeutic effect of the PBMNCs treatment can be stably maintained for 24 months, as revealed by the KOOS scores. These preclinical and pilot clinical data suggest that IA injection of MoFi-PBMNCs might serve as a novel medical technology to control the pain and the progress of KOA.

The Butterfly Fragment in Wedge-Shaped Femoral Shaft Fracture: Comparison of Two Different Surgical Methods.

OBJECTIVE: Our study compared the results of wedge-shaped femoral shaft fracture following intramedullary (IM) nailing with or without fixation of the third fragment. METHODS: We retrospectively reviewed patients presenting with femoral shaft fracture with AO/OTA type 32-B from 2011 to 2016. Patients were divided into two groups: closed reduction without touching the third fragment and open reduction with fixation of the third fragment. The fragment ratio, fragment length, nail size, dynamization or not, mRUST scores, union rate, and union time were compared between the two groups. Risk factors of non-union were also investigated, including sex, age, fracture pattern, fracture location, dynamization, nail size, fragment ratio, fragment size, and postoperative fragment displacement. RESULTS: A total of 80 patients met inclusion criteria, 20 patients with wedge-shaped shaft femoral fracture were managed with IM nailing and open reduction with fixation of the third fragment. Sixty patients were treated with IM nail without touching the third fragment. The union rate for the fixation and non-fixation groups were 60.0% and 81.7%, respectively. The mean union time for the fixation group was 19 months vs 14 months for the non-fixation group. Multi-regression analysis showed larger nail size (odds ratio: 2.26) and fixation of the third fragment (odds ratio: 0.18) influenced fracture healing. CONCLUSIONS: Fixation of the third fragment in wedge-shaped shaft femoral fracture results in a longer union time and lower union rate. In the management of femoral fracture with a third fragment, a larger nail size is recommended and fixation should be performed in a closed manner. Fixation of the fragment may achieve better fracture reduction. However, disruption of the vasculature and surrounding structures may further result in nonunion of the fracture site.

Amelioration of experimental tendinopathy by lentiviral CD44 gene therapy targeting senescence-associated secretory phenotypes.

CD44 exerts anti-senescence effects in many disease models. We examined senescence in tendinopathy and the effect of CD44 on senescence-associated secretory phenotypes (SASPs). Senescent markers were determined in human tendinopathic long head of bicep (LHB) and normal hamstring tendons. CD44 gene transfer in rat tendinopathic tenocytes stimulated with interleukin (IL)-1ß and a rat Achilles tendinopathy model were performed using lentiviral vectors. Expression levels of p53, p21, and p16 and senescence-associated ß-galactosidase (SA-ß-gal) activity were positively correlated with the severity of human tendinopathy and were higher in rat and human tendinopathic tenocytes than in normal controls. CD44 overexpressed tenocyte transfectants exhibited reduced levels of IL-6, matrix metalloproteinases (MMPs), cyclooxygenase (COX)-2, p53, p21, p16, SA-ß-gal, and phospho-nuclear factor (NF)-κB, whereas their collagen type I alpha 1 (COL1A1) and tenomodulin (tnmd) levels were increased when compared with control transfectants under IL-1ß-stimulated conditions. In the animal model, CD44 overexpression lowered the ultrasound and histology scores and expression levels of the senescent and SASP markers COX-2 and phospho-NF-κB. Bromodeoxyuridine (BrdU)- and tnmd-positive cell numbers were increased in the LVCD44-transduced tendinopathic tendons. Senescence is positively correlated with tendinopathic severity, and CD44 overexpression may protect the tendinopathic tendons from SASPs via anti-inflammation and maintenance of extracellular matrix homeostasis.

Neutral Nonenzymatic Glucose Biosensors Based on Electrochemically Deposited Pt/Au Nanoalloy Electrodes.

BACKGROUND: Type I diabetes occurs when the pancreas can only make limited or minimal insulin. Patients with type 1 diabetes need effective approaches to manage diabetes and maintain their blood-glucose concentration. Recently, continuous glucose monitoring (CGM) has been used to help control blood-glucose levels in patients with type 1 diabetes. Patients with type 2 diabetes may also benefit from CGM on multiple insulin injections, basal insulin, or sulfonylureas. Enzyme-free glucose detection in a neutral environment is the recent development trend of CGM. MATERIALS AND METHODS: Pt/Au alloy electrodes for enzyme-free glucose detection in a neutral environment were formed by electrochemically depositing Pt/Au alloy on a thin polycarbonate (PC) membrane surface with a uniformly distributed micro-hemisphere array. The PC membranes were fabricated using semiconductor microelectromechanical manufacturing processes, precision micro-molding, and hot embossing. Amperometry was used to measure the glucose concentration in PBS (pH 7.4) and artificial human serum. RESULTS: The Pt/Au nanoalloy electrode had excellent specificity for glucose detection, according to the experimental results. The device had a sensitivity of 2.82 µA mM-1 cm-2, a linear range of 1.39-13.9 mM, and a detection limit of 0.482 mM. Even though the complex interfering species in human blood can degrade the sensing signal, further experiments conducted in artificial serum confirmed the feasibility of the proposed Pt/Au nanoalloy electrode in clinical applications. CONCLUSION: The proposed Pt/Au nanoalloy electrode can catalyze glucose reactions in neutral solutions with enhancing sensing performance by the synergistic effect of bimetallic materials and increasing detection surface area. This novel glucose biosensor has advantages, such as technology foresight, good detection performance, and high mass production feasibility. Thus, the proposed neutral nonenzymatic glucose sensor can be further used in CGMs.

Synthesis of Multi-Functional Nano-Vectors for Target-Specific Drug Delivery.

Magnetic nanoparticles have gained attention in cancer therapy due to their non-toxic properties and high bio-compatibility. In this report, we synthesize a dual-responsive magnetic nanoparticle (MNP) that is sensitive to subtle pH and temperature change as in the tumor microenvironment. Thus, the functional doxorubicin (DOX)-loaded MNP (DOX-PNIPAM-PMAA@Fe3O4) can perform specific DOX releases in the cancer cell. The particle was characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), zeta-potential, Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The microscopy data revealed the particle as having a spherical shape. The zeta-potential and size distribution analysis data demonstrated the difference for the stepwise modified MNPs. The FTIR spectrum showed characteristic absorption bands of NH2-SiO2@Fe3O4, CPDB@Fe3O4, PMAA@Fe3O4, and PNIPAM-PMAA@Fe3O4. Drug-loading capacity and releasing efficiency were evaluated under different conditions. Through an in vitro analysis, we confirmed that PNIPAM-PMAA@Fe3O4 has enhanced drug releasing efficiency under acidic and warmer conditions. Finally, cellular uptake and cell viability were estimated via different treatments in an MDA-MB-231 cell line. Through the above analysis, we concluded that the DOX-loaded particles can be internalized by cancer cells, and such a result is positive and prospective.

Sanders classification of calcaneal fractures in CT images with deep learning and differential data augmentation techniques.

BACKGROUND: Classification of the type of calcaneal fracture on CT images is essential in driving treatment. However, human-based classification can be challenging due to anatomical complexities and CT image constraints. The use of computer-aided classification system in standard practice is additionally hindered by the availability of training images. The aims of this study is to 1) propose a deep learning network combined with data augmentation technique to classify calcaneal fractures on CT images into the Sanders system, and 2) assess the efficiency of such approach with differential training methods. METHODS: In this study, the Principle component analysis (PCA) network was selected for the deep learning neural network architecture for its superior performance. CT calcaneal images were processed through PCA filters, binary hashing, and a block-wise histogram. The Augmentor pipeline including rotation, distortion, and flips was applied to generate artificial calcaneus fractured images. Two types of training approaches and five data sample sizes were investigated to evaluate the performance of the proposed system with and without data augmentation. RESULTS: Compared to the original performance, use of augmented images during training improved network performance accuracy by almost twofold in classifying Sanders fracture types for all dataset sizes. A fivefold increase in the number of augmented training images improved network classification accuracy by 35%. The proposed deep CNN model achieved 72% accuracy in classifying CT calcaneal images into the four Sanders categories when trained with sufficient augmented artificial images. CONCLUSION: The proposed deep-learning algorithm coupled with data augmentation provides a feasible and efficient approach to the use of computer-aided system in assisting physicians in evaluating calcaneal fracture types.

Treating AO/OTA 44B lateral malleolar fracture in patients over 50 years of age: periarticular locking plate versus non-locking plate.

BACKGROUND: The role of locking plate in lateral malleolar fracture fixation for the elderly remains unclear. The aim of our study is to compare radiological and functional outcomes in older patients (> 50 years) with AO/OTA 44B lateral malleolar fractures after locking plate (PLP) or one-third non-locking tubular plate (TP) lateral fixation. METHODS: We retrospectively reviewed the medical records of 72 patients (PLP group, 34 patients; TP group, 38 patients; mean age, 61.9 ± 7.6 years; range, 51-80 years; follow-up, 1 year). Patients with open fractures, syndesmosis injuries, and a previous ankle trauma or surgery were excluded. Demographic data, union rate, complications, radiographic outcomes, visual analog scale (VAS) scores, and foot and ankle outcome scores (FAOSs) between the groups were recorded and compared. We also investigated the association of clinical features with pain and function. Statistically, the Fisher's exact test was used for categorical variables and the Mann-Whitney U test for the continuous variables. The final model for the multiple regression analysis was used to predict factors related to functional outcomes. RESULTS: There were no significant between-group differences in demographic data, complication rates, immediately postoperative distal fibula lengths, ankle osteoarthritis (OA) grades, talar tilt angles (TTAs) ≥ 2°, or reduction accuracy. All fractures achieved union. The PLP group had significantly lower rates of distal screw loosening, fibula shortening > 2 mm, OA grade progression, and TTAs ≥ 2°, and better FAOSs and VAS scores than was the case for the TP group after 1 year of follow-up (all p < 0.05). The severity of OA, TTA ≥ 2°, and distal screw loosening were positively associated with VAS scores, and negatively associated with FAOSs. CONCLUSIONS: When treating AO/OTA 44B fractures in patients over 50 years of age, PLPs provided better VAS scores, FAOSs, and radiological outcomes, including less fibula shortening > 2 mm, less osteoarthritic (OA) ankle progression, less implant removal rate, and fewer TTAs ≥ 2° than was the case for TPs after a 1-year follow-up. LEVEL OF EVIDENCE: Therapeutic level III.

A supplemental screw enhances the biomechanical stability in medial open-wedge high tibial osteotomy.

BACKGROUND: The supplemental screw technique was introduced for salvage of lateral hinge fracture in medial open-wedge high tibial osteotomy (owHTO). The efficacy of its use in protection of lateral hinge fracture and corresponding biomechanical behaviors remained unclear. The current study was aimed to clarify if a supplemental screw can provide better protection to lateral hinge in biomechanical perspective. MATERIALS: An in vitro biomechanical test was conducted. Tibial sawbones, commercial owHTO plates and a cannulated screw were utilized for preparing the intact, owHTO, and owHTO with cannulated screw insertion specimens. A "staircase" dynamic load protocol was adopted for axial compressive test with increasing load levels to determine structural strength and durability by using a material testing system, while a motion capture system was applied for determining the dynamic changes in varus angle and posterior slope of the tibia plateau with various specimen preparation conditions. RESULTS: Type II lateral hinge fracture were the major failure pattern in all specimens prepared with owHTO. The insertion of a supplemental cannulated screw in medial owHTO specimens reinforced structural stability and durability in dynamic cyclic loading tests: the compressive stiffness increased to 58.9-62.2% of an intact specimen, whereas the owHTO specimens provided only 23.7-29.2% of stiffness of an intact specimen. In view of tibial plateau alignment, the insertion of a supplemental screw improved the structural deficiency caused by owHTO, and reduced the posterior slope increase and excessive varus deformity by 81.8% and 83.2%, respectively. CONCLUSION: The current study revealed that supplemental screw insertion is a simple and effective technique to improve the structural stability and durability in medial owHTO.

Extra-articular endoscopic excision of symptomatic popliteal cyst with failed initial conservative treatment: A novel technique.

To reduce the damage to posteromedial knee capsule, we developed a direct extra-articular arthroscopic approach for excision of symptomatic popliteal cysts. This study aimed to demonstrate the surgical technique and present the 2-year follow-up results. Cystectomy is performed by extra-articular surgical approach through a high posteromedial portal. Twenty-one consecutive patients diagnosed of symptomatic popliteal cysts with failed initial conservative treatments were included. At a median follow-up of 29.4 months, all knees had improved clinical function assessed by Rauschning and Lindgren knee classification (p<0.001). The cysts were either disappeared (95.2%) or reduced in size (4.8%). Only one (4.8%) patient had recurrent cyst, which was solved after ultrasound-guided aspiration. This direct extra-articular arthroscopic technique could be a feasible alternative for treatment of symptomatic popliteal cysts.

Comparison of Mechanical Stability of Elastic Titanium, Nickel-Titanium, and Stainless Steel Nails Used in the Fixation of Diaphyseal Long Bone Fractures.

Elastic nails made of the nickel-titanium shape memory alloy (Nitinol) have been reported to control bone modeling in animal studies. However, the mechanical stability of the Nitinol nail in the fixation of long bone fractures remains unclear. This study compared mechanical stability among nails made of three materials, namely Nitinol, titanium, and stainless steel, in the fixation of long bone fractures. These three materials had identical shapes (arc length: π/2 and radius: 260 mm). A cylindrical sawbone with a 10-mm gap and fixed with two C-shaped elastic nails was used to examine the stability of the nails. A finite element (FE) model was developed based on the sawbone model. The end cap for elastic nails was not used in the sawbone test but was considered based on a constraint equation in FE simulation. The results of stability tests appeared to depend on the presence or absence of the end cap. In the sawbone test, the titanium nail yielded a higher ultimate force against the applied load than did the stainless steel and Nitinol nails before the gap completely closed; the difference in linear stiffness between the nails was nonsignificant. In FE simulation, the titanium nail produced smaller gap shortening than did stainless steel and Nitinol nails without the end cap; the difference in gap shortening between the nails was minor with the end cap. The titanium elastic nail should be a better choice in managing diaphyseal long bone fractures when the end cap is not used. For Nitinol and stainless steel nails, the end cap should be used to stop the nail from dropping out and to stabilize the fractured bone.

Fibroblast-seeded collagen gels in response to dynamic equibiaxial mechanical stimuli: A biomechanical study.

The remodeling of fibroblast-seeded collagen gels in response to dynamic mechanical stimuli was investigated by using a newly developed biaxial culture system capable of cyclically stretching planar soft tissues. Fibroblast-seeded collagen gels were subjected to three distinct dynamic mechanical conditions for six days: Cyclic Equibiaxial Stretching at two constant strain magnitudes (CES-7% and CES-20%), and Cyclic Equibiaxial Stretching with incrementally Increasing stain magnitude (ICES, 7% → 15% → 20% each for two days). The frequency of cyclic stretching was set at 1 Hz. At the end of culture, mechanical properties of the gels were examined by biaxial mechanical testing and checked again upon the removal of seeded cells. Collagen microstructure within the gels was illustrated by multiphoton microscopy. The mRNA levels of collagen type I and type III and fibronectin in the cells were examined by reverse transcription PCR. The protein expression of α-smooth muscle actin was detected by immunohistochemistry. We found that the gels cultured under cyclic stretching were stiffer than those cultured under static stretching. Particularly, the stiffness appeared to be significantly enhanced when the ICES was employed. The enhancement of mechanical properties by cyclic stretching appeared to persist upon cell removal, suggesting an irreversible remodeling of extracellular matrix. Second harmonic generation images showed that collagen fibers became thicker and more compact in the gels cultured under cyclic stretching, which may explain the mechanical findings. The mRNA expression of collagen type I in the cells of the ICES was significantly greater than that of the other groups except for the CES-20%. This study suggests that when cyclic stretching is to be used in engineering soft tissues, incrementally increasing strain magnitude may prove useful in the development of the tissue.