Metal Interference Research Articles

Antioxidative response to abiotic and biotic stresses in mangrove plants: A review

The natural environment for mangrove plants is composed of a complex set of abiotic and biotic stress factors that include salinity, heavy metal, low oxygen, flooding, UV‐B, water logging, and biotic interferences of various magnitude. Salinity stress exerts adverse effects on plants by disrupting the ionic and osmotic equilibrium of the cells leading to decrease in plant growth and development. Similarly, presence of heavy metals in environment induces a disturbance of the cellular redox balance, thereby affecting growth and productivity of mangrove plants. Anaerobic environment in mangroves manifested by anoxic or hypoxic condition exhibit various metabolic changes in plants to overcome the stress condition. Besides, the mangrove plants are also permanently exposed to various biotic stress factors that include microbial pathogens (viruses, bacteria and fungi), nematodes, insects etc. More often, these stress factors result in the production of reactive oxygen species (ROS) within different cellular compartments of the plant cell that are detrimental to the survival of the plants. However, the mangrove plants can withstand these stress conditions through morphological and physiological adaptations and development of an efficient antioxidative defence system composed of non‐enzymatic and enzymatic systems. The antioxidant system works in concert to control the cascades of uncontrolled oxidation and protect plant cells from oxidative damage by scavenging of ROS produced owing to different abiotic and biotic stresses. The present review highlights various abiotic and biotic stress conditions that are prevalent in mangrove environment and the manner in which mangrove plants overcome these stress situations through metabolic changes and induction of antioxidant defence system.

Tibial Tunnel Cyst Formation after Anterior Cruciate Ligament Reconstruction Using a Non-Bioabsorbable Interference Screw.

Tibial cyst formation following the use of bioabsorbable interference screws in anterior cruciate ligament (ACL) reconstruction is well-described; however, cyst formation after the use of metallic interference screws is not well-documented. We describe a case of osteolytic lesion of the proximal tibia presenting to us 20 years after ACL reconstruction using an autologous bone-tendon-bone graft. The original graft fixation technique was interference fixation with a metal screw in the tibial and femoral tunnels. A two-stage revision reconstruction of the ACL was undertaken with curettage and bone grafting of the tibial lesion in the first stage and reconstruction using a four-strand hamstring tendon in the second stage. The patient recovered satisfactorily with complete healing of the cyst and returned to pre-injury level of activities. We have reviewed case reports and case series that describe the aetiology of intra-osseous cyst formation following ACL reconstruction.

Interference of heavy metals on the photosynthetic response from a Cr(VI)-resistant Dictyosphaerium chlorelloides strain.

The successful selection of a particular type of bioelement and its association to the appropriate transducer determines the specificity of a biosensor. Therefore, from a strain of chloroficea Dictyosphaerium chlorelloides, modified in laboratory to tolerate high Cr(VI) concentrations, the possible interferences of other heavy metals on photosynthetic activity were studied. After exposing wild type and Cr(VI)-resistant cells to increasing Ag(+1), Co(+2), Hg(+2), Cr(+3), Cu(+2), Zn(+2), Fe(+3) and Cd(+2) concentrations, both photosynthetic quantum yields was compared. Photosynthetic electron transport rates were measured with a TOXY-PAM chlorophyll fluorometer, non-linear regression analysis of each of the toxicity tests was done, and means of both groups were compared using unpaired t test. The results show no significant differences between both cell types when they were exposed to Ag(+1), Co(+2), Hg(+2), Cr(+3), Cu(+2), Fe(+3) and Cd(+2) metal ions, and extremely significant differences (p<0.0001) to Zn(+2) exposures. These results demonstrate the suitability of this Cr(VI)-resistant type D. chlorelloides strain as a suitable bioelement to be coupled to a biosensor based on dual-head microalgae strategy to detect and quantify Cr(VI) in water courses and waste water treatment plants. However, some disturbance may be expected, especially when certain analyte species such as zinc are present in water samples tested. The analysis of binary mixtures between Zn(+2) and other heavy metals showed a slight antagonistic phenomenon in all cases, which should not alter the potential Zn(+2) interference in the Cr(+6) detection process.

COMPARISON OF AN ELECTROMAGNETIC AND OPTICAL SYSTEM DURING DYNAMIC MOTION

Few studies have concurrently investigated the accuracy and repeatability of an optical and electromagnetic (EM) system during dynamic motion. The purposes of this study were to: (1) assess the accuracy of both an EM and optical system when compared to a gold standard and (2) to compare the intra- and inter-day repeatability during 3D kinematic motion of both systems. The gold standard used for accuracy assessment was a robot programmed to manipulate a carbon fiber beam through pre-defined motions within the capture volume of both systems at 30, 45 and 60°/s. A total of 12 healthy young adults were tested for intra- and inter-day repeatability of hip, knee and ankle joint angles during a sit-to-stand movement. Marker trajectories were captured using an 8-camera Motion Analysis system and a Polhemus Liberty system. Optical markers for both portions of the study were precisely marked to allow for digitization by the EM system, with collections taken at 120 Hz. Accuracy and repeatability were assessed using the RMS error and coefficient of multiple correlations (CMC), respectively. The optical system demonstrated a 1–2.5° lower RMS error in tracking the robot movements in the transverse and sagittal planes when compared to the EM system. However, it was possible that metal interference affected the accuracy of the EM system. High intra-day and inter-day repeatability was demonstrated by both systems during the sit-to-stand task. The optical system did demonstrate slightly higher CMC values for between day trials, though skin motion artifact might have affected the EM system to a greater extent. Overall, both systems demonstrated an adequate ability to track dynamic motion.

Coherence and aberration effects in surface plasmon polariton imaging.

We study theoretically and experimentally coherent imaging of surface plasmon polaritons using either leakage radiation microscopy through a thin metal film or interference microscopy through a thick metal film. Using a rigorous modal formalism based on scalar Whittaker potentials, we develop a systematic analytical and vectorial method adapted to the analysis of coherent imaging involving surface plasmon polaritons. The study includes geometrical aberrations due index mismatch which played an important role in the interpretation of recent experiments using leakage radiation microscopy. We compare our theory with experiments using classical or quantum near-field scanning optical microscopy probes and show that the approach leads to a full interpretation of the recorded optical images.

Automatic BSS-based filtering of metallic interference in MEG recordings: definition and validation using simulated signals

Objective. One of the principal drawbacks of magnetoencephalography (MEG) is its high sensitivity to metallic artifacts, which come from implanted intracranial electrodes and dental ferromagnetic prosthesis and produce a high distortion that masks cerebral activity. The aim of this study was to develop an automatic algorithm based on blind source separation (BSS) techniques to remove metallic artifacts from MEG signals. Approach. Three methods were evaluated: AMUSE, a second-order technique; and INFOMAX and FastICA, both based on high-order statistics. Simulated signals consisting of real artifact-free data mixed with real metallic artifacts were generated to objectively evaluate the effectiveness of BSS and the subsequent interference reduction. A completely automatic detection of metallic-related components was proposed, exploiting the known characteristics of the metallic interference: regularity and low frequency content. Main results. The automatic procedure was applied to the simulated datasets and the three methods exhibited different performances. Results indicated that AMUSE preserved and consequently recovered more brain activity than INFOMAX and FastICA. Normalized mean squared error for AMUSE decomposition remained below 2%, allowing an effective removal of artifactual components. Significance. To date, the performance of automatic artifact reduction has not been evaluated in MEG recordings. The proposed methodology is based on an automatic algorithm that provides an effective interference removal. This approach can be applied to any MEG dataset affected by metallic artifacts as a processing step, allowing further analysis of unusable or poor quality data.

Graft tendon slippage with metallic and bioabsorbable interference screws under cyclic load: a biomechanical study in a porcine model

Introduction The rupture of the anterior cruciate ligament (ACL) is the most common type of knee injury. Reconstructive surgery is the ‘gold standard’ treatment. During the immediate post-operative period, the fixation of the graft is entirely dependent on the ability of the grafted implant to be secured inside the bone tunnel under the cyclical loads associated with daily tasks. Poor fixation can lead to graft slippage, thus impairing the healing and integration of the graft. The aim of this study was to evaluate the biomechanical performance of tendon graft fixation devices with metallic and bioabsorbable interference screws. Methods Twenty ACL reconstructions were carried out in porcine tibias using deep flexor tendons to fix 9 × 20 mm metallic (n=10) and PLLA 70/30 bioabsorbable screws (n=10). To verify the ability of a construct to resist immediate postoperative (PO) rehabilitation protocols for immediate load bearing, a cyclic loading test was applied with 50-250 N of tensile force at 1 Hz for 1000 cycles, and the displacement was measured at 10, 50, 100, 500 and 1000 load cycles to quantify the slippage of the graft during the test. After the cyclic loading test, a single-cycle load-to-failure test was applied. Results The slippage of the graft using metallic screws did not differ (P = 0.616) from that observed when using bioabsorbable screws. Conclusion The results obtained in this experiment indicate that metallic screws may promote a similar amount of graft slippage during low cyclic loading as bioabsorbable screws. Additionally, there was no difference in the biomechanical performance of these two types of screws during high failure loads.

Sensitive electrochemical sensor using a graphene–polyaniline nanocomposite for simultaneous detection of Zn(II), Cd(II), and Pb(II)

This work describes the development of an electrochemical sensor for simultaneous detection of Zn(II), Cd(II), and Pb(II) using a graphene–polyaniline (G/PANI) nanocomposite electrode prepared by reverse-phase polymerization in the presence of polyvinylpyrrolidone (PVP). Two substrate materials (plastic film and filter paper) and two nanocomposite deposition methods (drop-casting and electrospraying) were investigated. Square-wave anodic stripping voltammetry currents were higher for plastic vs. paper substrates. Performance of the G/PANI nanocomposites was characterized by scanning electron microscopy (SEM) and cyclic voltammetry. The G/PANI-modified electrode exhibited high electrochemical conductivity, producing a three-fold increase in anodic peak current (vs. the unmodified electrode). The G/PANI-modified electrode also showed evidence of increased surface area under SEM. Square-wave anodic stripping voltammetry was used to measure Zn(II), Cd(II), and Pb(II) in the presence of Bi(III). A linear working range of 1–300μgL−1 was established between anodic current and metal ion concentration with detection limits (S/N=3) of 1.0μgL−1 for Zn(II), and 0.1μgL−1 for both Cd(II) and Pb(II). The G/PANI-modified electrode allowed selective determination of the target metals in the presence of common metal interferences including Mn(II), Cu(II), Fe(III), Fe(II), Co(III), and Ni(II). Repeat assays on the same device demonstrated good reproducibility (%RSD<11) over 10 serial runs. Finally, this system was utilized for determining Zn(II), Cd(II), and Pb(II) in human serum using the standard addition method.

Changes of transmission characteristics for different optic radiation incidence angles in filters protecting against hazardous infrared radiation

AbstractThe paper presents the fundamental information concerning the types of protective optical filters used for protection against hazardous radiation within the visible and near-infrared spectrum range. The changes of transmission characteristics for different optic radiation angles of incidence with metallic reflective filters and interference filters have been analyzed. The results demonstrate that such changes exert no effect on the level of protection provided by the filters.

Development of magnetic separation and quantum dots labeled immunoassay for the detection of mercury in biological samples

A rapid and sensitive immunoassays of mercury (Hg) in biological samples was developed using quantum dots (QDs) and magnetic beads (MBs) as fluorescent and separated probes, respectively. A monoclonal antibody (mAb) that recognizes an Hg detection antigen (BSA-DTPA-Hg) complex was produced by the injection of BALB/c mice with an Hg immunizing antigen (KLH-DTPA-Hg). Then the ascites monoclonal antibodies were purified. The Hg monoclonal antibody (Hg-mAb) is conjugated with MBs to separate Hg from biological samples, and the other antibody, which is associated with QDs, is used to detect the fluorescence. The Hg in biological samples can be quantified using the relationship between the QDs fluorescence intensity and the concentration of Hg in biological samples following magnetic separation. In this method, the detection linear range is 1–1000ng/mL, and the minimum detection limit is 1ng/mL. The standard addition recovery rate was 94.70–101.18%. The relative standard deviation values were 2.76–7.56%. Furthermore, the Hg concentration can be detected in less than 30min, the significant interference of other heavy metals can be avoided, and the simultaneous testing of 96 samples can be performed. These results indicate that the method could be used for rapid monitoring Hg in the body.

Mechanical properties of orthodontic wires made of super engineering plastic.

Most orthodontic equipment is fabricated from alloys such as stainless steel, Co-Cr and Ni-Ti because of their excellent elastic properties. In recent years, increasing esthetic demands, metal allergy and interference of metals with magnetic resonance imaging have driven the development of non-metallic orthodontic materials. In this study, we assessed the feasibility of using three super engineering plastics (PEEK, PES and PVDF) as orthodontic wires. PES and PVDF demonstrated excellent esthetics, although PEEK showed the highest bending strength and creep resistance. PEEK and PVDF showed quite low water absorption. Because of recent developments in coloration of PEEK, we conclude that PEEK has many advantageous properties that make it a suitable candidate for use as an esthetic metal-free orthodontic wire.

Strength of lime-cement stabilized tropical lateritic clay contaminated by heavy metals

Cement and lime are considered as stabilizers of contaminated land since they can reduce the leachability of contaminants. The contaminated soils can generally have higher strength after stabilization. However, the presence of heavy metal contaminants in soil interferes with stabilizer hydration which inhibits strength development in treated soils. Stabilizing products also have different strength properties due to heavy metals that affect levels of chemical fixation in different contaminated soil mixes. This paper presents an experimental study that evaluates strength development in cement-lime stabilized/solidified soils contaminated with either copper or zinc. Unconfined compressive strength was used to determine the suitability of cement and lime stabilization of contaminated laterite clay soils. Control samples (cement-lime stabilized soils without heavy metals) were prepared for comparison. Results confirmed the interference of heavy metals in the process of cement and lime hydration as a direct reflection of varied strength developments in tested soil samples. It was found that metal concentration, stabilizer content, type of stabilizer, and heavy metal type were factors that affected stabilizer hydration and strength development. The most significant ones of these were the type of stabilizer used and heavy metal concentration.

The effect of UV irradiation on PSf/TiO2 mixed matrix membrane for chromium rejection

The study investigated a novel approach for surface modification of membranes and sustainable water recovery from chromium contaminated water by employing a lab scale dead-end cell filtration unit. Various PSf/TiO2 composite membranes prepared with different concentrations of TiO2 nanoparticles were exposed to UV radiations for surface modification. On exposure to UV light, TiO2 nanoparticles emit electrons and create a surface roughness with a charge on the membranes which resulted in enhanced chromium rejection as well as flux. The surface modification has been analyzed by AFM and SEM (surface and cross sectional) images. The structural modification was investigated by ATR-IR and UV–Visible spectroscopy. The expected enhancement in hydrophilicity was studied by water uptake and contact angle measurements. The analysis of water flux and chromium rejection performed in a dead end filtration unit revealed a high water flux and 100% chromium rejection with 2wt.% of TiO2 composite membrane in acidic pH. The pH of feed plays an important role in chromium rejection. The rejection of chromium decreases with an increase in feed concentration due to the variation in ion distribution. The effect of interference of other metals in chromium rejection is investigated. The overall work not only demonstrates the positive effects of surface modification, but also effective removal of hazardous chromium.

Fixation techniques for the anterior cruciate ligament reconstruction: early follow-up. A systematic review of level I and II therapeutic studies.

The purpose of our study was that to systematically review the fixation techniques for the ACL reconstruction and associated clinical outcomes at the early follow-up. Systematic search on three electronic databases (Cochrane register, Medline and Embase) of fixation devices used for primary ACL reconstruction with doubled semitendinosus and gracilis and bone-patellar tendon-bone autografts in randomized clinical trials of level I and II of evidence published from January 2001 to December 2011. Therapeutic studies collected were with a minimum 12-month follow-up, and the clinical outcomes were evaluated by at least one of International Knee Documentation Committee, Lysholm and Tegner functional scales and at least one of the following knee stability tests: arthrometric AP tibial translation, Lachman test and pivot-shift test. Nineteen articles met the inclusion criteria. At the femoral side cross-pin, metallic interference screw, bioabsorbable interference screw, and suspensory device were used in 32.3, 27.3, 24.8, 15.5% of patients, respectively. At the tibial side fixation was achieved with metallic interference screw, bioabsorbable interference screw, screw and plastic sheath, screw post and cross-pin in 38.7, 31, 15.7, 12.8, and 1.7% of patients, respectively. Side-to-side anterior-posterior tibial translation was 1.9 ± 0.9, 1.5 ± 0.9, 1.5 ± 0.8, 2.2 ± 0.4 mm for metallic interference screw, bioabsorbable screw, cross-pin and suspensory device, respectively. At least two-third of all the patients achieved good-to-excellent clinical outcomes. Rate of failure was 6.1, 3.3, 1.7 and 1.2% for bioabsorbable interference screw, metallic interference screw, cross-pin and suspensory device, respectively. Clinical outcomes are good to excellent in almost two-third of the patients but several pitfalls that affect the current fixation techniques as graft tensioning such as graft-tunnel motion are still unaddressed.

The chromium detoxification pathway in the multimetal accumulator Silene vulgaris.

Phytomanagement could be a viable alternative in areas polluted with wastes from chromium-using industries. This study investigated the ability of Silene vulgaris to take up Cr(III) and Cr(VI) with special attention on the mechanism used by this species to tolerate high doses of Cr(VI). Plants were grown semihydroponically with different concentrations of either Cr(III) or Cr(VI). A combination of synchrotron X-ray spectroscopic techniques, scanning electron and light microscopy and infrared spectroscopy were used to determine the distribution and speciation of Cr. S. vulgaris accumulated more Cr when grown with Cr(VI) resulting in an overall reduction in biomass. Starch accumulation in leaves may be attributed to an impartment between carbon utilization and assimilation resulted from stunted plant growth but not the complete inhibition of photosynthesis indicating that S. vulgaris possess tolerance mechanisms that allows it to survive in Cr(VI) rich environments. These primary tolerance mechanisms are (a) the total reduction of Cr(VI) to Cr(III) in the rhizosphere or just after uptake in the fine lateral root tips and (b) chelation of Cr(III) to the cell wall both of which reduce metal interference with critical cell functions. These mechanisms make S. vulgaris suitable for in situ remediation of Cr polluted soils.

Write Once, Read Forever (WORF): Low-energy storage in perpetuity of high-density, multi-state data

Successful archiving of data requires a storage medium capable of persisting for times measured in centuries, and providing an absolute trust in supportable and permanent hardware. While all media decay, data on magnetic media, solid-state drives and conventional optical disks must be cyclically refreshed over relatively short time frames, requiring energy and labor resources. We propose a "Write-Once, Read Forever" (WORF) module specifically engineered for long-term preservation of digital data. It uses a novel high-density data storage medium based on silver halide, which has been demonstrated to last for more than a century under normal ambient environmental conditions. Once data is written to WORF, energy is needed only for reading&#x2014;no periodic refresh is necessary, and data is both immutable and truly permanent. Human readable text and images are embedded in the WORF module adjacent to the digital data. This text and imagery contains metainformation about the media's content, and instructions for decoding for future generations. WORF digital data is stored as microscopic, metallic interference gratings (representing wavelengths or "colors") embedded in a modern, super-resolution, dye-free, photosensitive emulsion. Wavelengths encode multiple states per data region; current spectroscopic technology makes 400 states per 2 micron diameter data region feasible. Multi-state data architecture within each domain enhances data integrity, error-checking, and accelerates writing and reading for the entire media module.

A randomized prospective controlled study with 5-year follow-up of cross-pin femoral fixation versus metal interference screw fixation in anterior cruciate ligament reconstruction.

The purpose of this study was to determine and compare mid- to long-term results of cross-pin versus metal interference screw fixation of ACL graft. In a prospective trial, 62 patients were randomized into two groups based on method of fixation. Transtibial drilling technique was used in the cross-pin and outside-in femoral drilling in the interference screw fixation group. Clinical and radiographical outcomes were assessed 2 and 5years postoperatively. The study showed no clinically significant difference with respect to method of graft fixation. Mean anteroposterior side-to-side instrumented laxity difference was 2.4mm in the cross-pin group and 2.5mm in the screw group (n.s.). Median Tegner and mean Lysholm scores at 5years were 6 (range 3-9) and 92.2 (range 69-100) in the screw group and 7 (3-10) and 93.3 (82-100), respectively, in the cross-pin group. Radiographical osteoarthritis increased in both groups from 2 to 5years after reconstruction (p<0.05), especially in the medial and patellofemoral joint spaces. Widening of the drill tunnels continued from 2 to 5years without clinical significance. The method of graft fixation did not yield a difference in clinical or radiographical outcome at 5years. Results were excellent in both groups. I.

Comparison of Pull-out Strength for Different Bone Block Length in a Porcine Anterior Cruciate Ligament Model.

Background:Bone block length for bone–patellar tendon–bone (BPTB) anterior cruciate ligament (ACL) reconstruction has traditionally been 25 mm in length. The previous surgical technique did not require the surgeon to pay particular attention to the length of the bone block, and therefore, there is scant evidence in the literature describing ideal lengths. With the gaining popularity of accessory medial portal drilling of the femoral tunnel, concerns with tunnel length and graft shuttling have surfaced. Newer techniques have advised shortening of the femoral bone block to accommodate the shorter tunnel and for ease of bone block manipulation into the aperture of the tunnel.Purpose:To compare the effects of bone block length on the pull-out strength of patellar tendon grafts using metal interference screws in a porcine ACL reconstruction model. The hypothesis was that the pull-out strength of each length of bone block under cyclic and ultimate load to failure testing would surpass the physiologic loads experienced by a normal ACL.Study Design:Controlled laboratory study.Methods:This study used 27 unmatched porcine femurs and BPTB constructs. Specimens were randomly assigned to a 10-, 15-, or 20-mm bone block reconstruction and a cycle load of 100, 500, or 1000 cycles. This resulted in 9 specimen groups with 3 specimens in each group. A central composite design (CCD) for the test matrix was selected, as this was optimum for requiring relatively few experiments while still exploring the complete range of interest for 2 independent variables. Each reconstruction used a 7 × 20–mm titanium interference screw. All reconstructions were performed on the femoral side using 10-mm-wide patellar tendon grafts, and tensile tests were performed. The loading protocol started with a 20-N preload, then cyclic testing to the appropriate number of cycles in the elastic region between 50 and 150 N at a strain rate of 200 mm/min, and then ended with ultimate load-to-failure testing. Ultimate load to failure, peak stress, elongation, and stiffness were all recorded. The patellar tendon graft mode of failure was measured by visual inspection.Results:During load-to-failure testing, 5 of 9 graft constructs in the 10-mm group failed at the bone block, while 2 of 9 failed in the 15-mm group at this interface. In the 20-mm group, all 9 specimens failed at the tendon, and none failed at the bone block. There was a statistically significant difference in modes of failure between the bone block length groups in the reconstructed ACL grafts. Analysis indicates that a smaller bone block length graft is more likely to fail due to a bone block failure than a tendon failure. The average ± standard deviation failure load for all specimens was 573 ± 171 N. The mean failure loads for the 10-, 15-, and 20-mm groups were 614 ± 110, 658 ± 92, and 540 ± 203 N, respectively. There was no statistical significance between the groups in any of these measurements.Conclusion:Bone blocks of 20 to 25 mm in length are normally used in surgical practice. Thus, the purpose of this study was to explore the effects of a smaller bone block length in the fixation strength of a graft. This study could not yield a significant difference in failure load for differently sized bone blocks. There was a significant tendency of shorter bone block lengths to fail due to bone block failure.Clinical Relevance:Bone block failure was defined as slippage of the bone block or interference screw. These results show that using a smaller bone block may increase the likelihood of a graft failure in an ACL reconstruction.

Surgical Predictors of Early Revision Surgery After Anterior Cruciate Ligament Reconstruction

Background: An important objective of anterior cruciate ligament (ACL) registries is to detect and report early graft failure and revision surgery after ACL reconstruction. Purpose: To investigate surgical variables and identify predictors of revision surgery after ACL reconstruction. Study Design: Prospective cohort study; Level of evidence, 2. Methods: This prospective cohort study was based on data from the Swedish National Knee Ligament Register during the years 2005 through 2011. Eight surgical variables were investigated: graft selection, graft width, single-bundle or double-bundle techniques, femoral graft fixation, tibial graft fixation, injury-to-surgery interval, injuries to menisci, and injuries to cartilage. The primary endpoint was the 2-year incidence of revision surgery. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated and adjusted for confounders by use of multivariate statistics. Results: A total of 13,102 patients were included (5541 women [42%] and 7561 men [58%]; P < .001). Hamstring tendon autografts accounted for 90% (11,764 patients) of all reconstructions, of which 96% were performed with a single-bundle technique (11,339 patients). Patellar tendon autografts accounted for the remaining 10% (1338 patients). At index reconstruction, observed injuries to menisci and cartilage were common (40% and 28%, respectively). The overall 2-year incidence of revision surgery was 1.60% (women, 1.57%; men, 1.63%; P = .854). Patients with metal interference screw fixation of a semitendinosus tendon autograft on the tibia had a significantly reduced risk of early revision surgery (RR = 0.32; 95% CI, 0.12-0.90; P = .031). Conclusion: Metal interference screw fixation of a semitendinosus tendon autograft on the tibia was an independent predictor of significantly lower 2-year incidence of revision surgery. Graft selection, graft width, a single-bundle or a double-bundle technique, femoral graft fixation, the injury-to-surgery interval, and meniscus injury were not predictors of early revision surgery.

A Comparison of Functional Outcomes After Metallic and Bioabsorbable Interference Screw Fixations in Arthroscopic ACL Reconstructions.

Anterior Cruciate Ligament (ACL) is as one of the most frequently injured ligaments in the modern contact sports scenario. Graft fixations can be achieved during anterior cruciate ligament (ACL) reconstructions by using either bioabsorbable screws or metal screws. The objective of this study was to compare the functional outcomes after bioabsorbable and metallic interference screw fixations in arthroscopic anterior cruciate ligament reconstructions done by using hamstring grafts. This was a prospective, randomized study. Patients in Group 1 received bioabsorbable interference screws and patients in Group 2 received metallic interference screws. Arthroscopic assisted, anterior cruciate ligament reconstructions with the use of hamstring grafts which were fixed proximally with endobuttons and distally with bioabsorbable or metallic interference screws, were undertaken. Progress in functional outcomes was assessed by using Mann Whitney U- test. Functional outcomes in the two groups were compared by using independent t-test. In each group, there were statistically significant improvements in functional outcomes over successive follow-ups, which were seen on basis on Mann-Whitney U-test. The comparison of functional outcomes between the two groups, done by using independent t-test, showed no statistically significant differences between the two groups at 3 months, 6 months and 1 year of follow-up. p-value <0.05 was considered to be significant in our study. In our prospective study of comparison of functional outcomes between bioabsorbable and metallic interference screws in arthroscopic anterior cruciate ligament reconstuctions, which were evaluated by using Tegner activity scale and Lysholm knee scoring scale for a period of 1 year, no statistically significant difference was found. However, further authentication is required by doing long term studies.