Tunnel Size Research Articles

Quantitative Analysis of the Carpal Tunnel and Its Inner Structures in Primates.

To explore the anatomical factors potentially involved in the high incidence of carpal tunnel syndrome in humans, we have quantified the anatomical variations of the carpal tunnel and its inner structures in humans, non-hominoid primates (monkeys), and hominoid primates (apes). In specimens of six humans, eight monkeys, and three apes, we assessed the size of the carpal tunnel, the tendons of the digit flexor muscles, and the median nerve. We compared the size of the carpal tunnel normalized by the wrist size, and the size of the median nerve and the tendons of the digit flexors normalized by the size of the carpal tunnel. Differences between humans and monkeys were calculated using the T test or Mann-Whitney U test, as appropriate. Data on the apes were not included in the statistical analyses due to the small sample size. The normalized size of the carpal tunnel was similar in all specimens. The normalized size of the tendons of the digit flexors was smaller in humans, while that of the median nerve was significantly larger. The median nerve was also larger in apes than in monkeys. The relatively larger median nerve observed in humans could suggest a greater vulnerability of the nerve to compression, which could predispose humans to carpal tunnel syndrome. However, the tendons of the digit flexor muscles were smaller in humans, and moreover, the proportional size of the median nerve was similar in apes, leading us to suggest that the factors predisposing humans to carpal tunnel syndrome must be sought beyond anatomical features and may be more closely related to functional or personal parameters.

Predictors of Residual Right to Left Shunt in Patients Undergoing Percutaneous Transcatheter Patent Foramen Ovale Closure: A New Clue "Inferior Vena Cava-Patent Foramen Ovale Angle".

Background: Many different devices are currently used for percutaneous patent foramen ovale (PFO) closure (pPFOc), aiming to achieve complete occlusion to prevent recurrent embolism. We aimed to reveal the association between residual right-to-left shunt (RLS) after pPFOc and baseline structural features of the PFO determined using transoesophageal echocardiography (TEE) before the procedure. Methods: This is a single-center cross-sectional study. A total of 123 patients who underwent pPFOc for cryptogenic stroke (CS) were screened, consecutively. Patients were compared based on the presence of residual RLS. The association of structural features of the PFO with residual RLS was evaluated using logistic regression analysis. Results: The procedure was successfully completed in a total of 103 patients included in the study after exclusion and 21% had significant residual RLS. During a median follow-up of 18 months, one patient died at 25 months due to malignancy, recurrent CS were observed in 5 (5%) patients, and atrial fibrillation was detected in 3 (3%) patients. No significant difference was observed in the baseline clinical characteristics and laboratory parameters among the patients. In addition to atrial septal aneurysm (ASA), aortic rim, tunnel width and length; inferior vena cava (IVC)-PFO tunnel angle was associated with residual RLS with a cut-off 11.3 (AUC: 0.786, 64% sensitivity, 87% specificity, p < 0.001). In individuals with residual RLS, longer and wider tunnel size, rudimentary aortic rim, acute IVC-PFO tunnel angle, and decreased tunnel length-left disc ratio were observed. Conclusions: IVC-PFO tunnel angle is a novel parameter and provides benefit to detect significant RLS in pPFOc patients.

The Tibial Tunnel Size Relative to the Proximal Tibia Affects the Tibial Tunnel Widening in Anatomical Anterior Cruciate Ligament Reconstruction.

The impact of the bone tunnel size relative to body size on clinical results in anterior cruciate ligament (ACL) reconstruction remains unclear. This study aimed to assess the morphological alteration of the tibial tunnel aperture and relationship between the tibial tunnel size relative to the proximal tibia among the tibial tunnel widening (TW) and clinical results following ACL reconstruction. This study comprised 131 patients who had undergone anatomical ACL reconstruction utilizing bone-patellar tendon-bone autografts. The morphology and enlargement of the tibial tunnel were examined via three-dimensional computed tomography 1 week and 1 year postoperatively. The anteroposterior (AP) and mediolateral (ML) positions were determined as a percentage relative to the proximal AP and ML tibial dimensions, respectively. Clinical assessment was conducted 2 years postoperatively. The association between the primary tibial tunnel size among TW and clinical outcomes was examined. The tibial tunnel significantly migrated posterolaterally. The ML diameter significantly widened; however, the AP diameter did not exhibit widening. AP widening was associated with the AP diameter of the primary tibial tunnel (r = -0.482, p < 0.01), and ML widening correlated with the ML diameter of that tunnel (r = -0.478, p < 0.01). However, there was no significant correlation observed between the primary tibial tunnel size and clinical outcomes. The tibial tunnel migrated and enlarged laterally in the ML plane, but did not enlarge in the AP plane. The primary tibial tunnel diameter relative to the proximal tibia negatively correlated with the tibial TW in the AP and ML planes. Level of evidence: level IV.

Steady-State Temperature Prediction for Cluster-Laid Tunnel Cables Based on Self-Modeling in Natural Convection

Accurate temperature prediction of the operating tunnel cable is crucial for its safe and efficient function. To achieve a rapid and accurate prediction of the steady-state temperature of the tunnel cable, the self-modeling pattern in natural convection on the cable surface in the rectangular tunnel is investigated, and the self-modeling method for the convective heat transfer coefficient calculation is proposed. A thermal circuit model for single cables is further established to predict the cable core temperature, and the model is extended to predict the cluster-laid cable core temperature based on the combined method. The results show that when the tunnel size is neglected, the maximum relative deviation of the convective heat transfer coefficient between the self-modeling method and the finite element simulation is only 1.78% in the studied cases, indicating that the natural convection on the cable surface approximately satisfies the self-modeling method. Additionally, applying the self-modeling method to the thermal circuit can accurately predict the temperature of the single cable core. Furthermore, for the three-phase four-circuit cable, the maximum deviation between the temperature prediction results and the finite element results is within 2 K in the studied cases, which verifies the predictive accuracy of the combined method for the cluster-laid tunnel cable.

Surgical Technique for Revision of Anterior Cruciate Ligament Reconstruction, Combined with Postero-Lateral Corner and Anterolateral Ligament Reconstruction Using the Same Femoral Tunnel for Reconstruction of These Structures

Objectives The reconstruction of the anterior cruciate ligament (ACL) is the most performed knee surgery in Brazil; consequently, the number of failures in this reconstruction has increased. Each year, the exponential rise in ACL revision surgeries is linked to undiagnosed and untreated injuries. Possible causes of failures should be assessed, including the size and positioning of femoral and tibial tunnels, neglected ligament and meniscal injuries, rotational instabilities, and axis deviations. This article aims to describe a surgical technique for revising ACL reconstruction, associated with the posterolateral corner and anterolateral ligament, using the same femoral tunnel with autograft. Therefore, the article emphasizes the importance of preoperative diagnosis and the treatment of meniscal and ligament injuries associated with ACL injury. This new technique proves to be reliable, easily reproducible, providing adequate stability, reducing the number of femoral tunnels, and minimizing the chance of tunnel convergence, utilizing autologous grafts. Methods description of Surgical Technique for Revision of Anterior Cruciate Ligament Reconstruction, Combined with Posterolateral Corner and Anterolateral Ligament Reconstruction Using the Same Femoral Tunnel for Reconstruction of These Structures. Results Patients who underwent ACL revision with the technique described presented adequate anterolateral and rotational stability, compared to other reconstruction techniques of the posterolateral corner and anterolateral ligament. Conclusion The surgical technique described above generated stability in the revision of the ACL, as it was associated with simple peripheral ligament reconstruction using autologous tendons. This new technique appears to be reliable, easy to reproduce, generating adequate stability, thus reducing the number of femoral tunnels and the chance of confluence of these tunnels.

A Novel Machine Learning Model to Predict Revision ACL Reconstruction Failure in the MARS Cohort.

As machine learning becomes increasingly utilized in orthopaedic clinical research, the application of machine learning methodology to cohort data from the Multicenter ACL Revision Study (MARS) presents a valuable opportunity to translate data into patient-specific insights. To apply novel machine learning methodology to MARS cohort data to determine a predictive model of revision anterior cruciate ligament reconstruction (rACLR) graft failure and features most predictive of failure. Cohort study; Level of evidence, 3. The authors prospectively recruited patients undergoing rACLR from the MARS cohort and obtained preoperative radiographs, surgeon-reported intraoperative findings, and 2- and 6-year follow-up data on patient-reported outcomes, additional surgeries, and graft failure. Machine learning models including logistic regression (LR), XGBoost, gradient boosting (GB), random forest (RF), and a validated ensemble algorithm (AutoPrognosis) were built to predict graft failure by 6 years postoperatively. Validated performance metrics and feature importance measures were used to evaluate model performance. The cohort included 960 patients who completed 6-year follow-up, with 5.7% (n = 55) experiencing graft failure. AutoPrognosis demonstrated the highest discriminative power (model area under the receiver operating characteristic curve: AutoPrognosis, 0.703; RF, 0.618; GB, 0.660; XGBoost, 0.680; LR, 0.592), with well-calibrated scores (model Brier score: AutoPrognosis, 0.053; RF, 0.054; GB, 0.057; XGBoost, 0.058; LR, 0.111). The most important features for AutoPrognosis model performance were prior compromised femoral and tibial tunnels (placement and size) and allograft graft type used in current rACLR. The present study demonstrated the ability of the novel AutoPrognosis machine learning model to best predict the risk of graft failure in patients undergoing rACLR at 6 years postoperatively with moderate predictive ability. Femoral and tibial tunnel size and position in prior ACLR and allograft use in current rACLR were all risk factors for rACLR failure in the context of the AutoPrognosis model. This study describes a unique model that can be externally validated with larger data sets and contribute toward the creation of a robust rACLR bedside risk calculator in future studies. NCT00625885 (ClinicalTrials.gov identifier).

Morphological characteristics of rabbits’ carpal tunnel: Evaluation of its potential for carpal tunnel research

This study aimed to define the main anatomic components and describe the normal size and form of the carpal tunnel in rabbits using imaging techniques. It was also aimed to evaluate the potential of rabbits as an animal model for carpal tunnel research. The forelimbs of eight adult New Zealand rabbits were investigated using histology, magnetic resonance, and computed tomography. Two cadavers were used for anatomical dissection to support the findings. The carpal tunnel was examined at proximal and distal levels, and it was found that the flexor retinaculum is two-layered in rabbits. Both vascular nerve bundles, including the median nerve and the ramus palmaris of the ulnar nerve, were within two layers of it and passed through the carpal tunnel. The deep digital flexor, superficial digital flexor, and radial carpal flexor tendons were observed within the carpal tunnel. The flexor pollicis longus tendon is not found in rabbits. The area of the carpal tunnel narrowed towards the distal end in three methods, and its depth decreased in CT and MRI. The length of the accessory carpal bone determined this depth. The study found that rabbits' carpal tunnels are morphologically similar to those of humans compared to dogs. This situation is thought to pave the way for more accurate approaches to carpal tunnel research in rabbits.

Novel lateral tunnel Fontan operation in children promotes continued pathway growth into adulthood

ObjectiveMost Fontan operation techniques currently used in children are limited by a blood flow pathway with no growth potential. The external pericardial lateral tunnel Fontan is a novel technique using the patient's pedicled pericardium and atrial wall in situ to create a Fontan pathway. We hypothesize that viable, autologous tissue will allow growth potential of the pathway and adapt to increasing physiologic demands of somatic growth. MethodsWe performed a single-center retrospective review of serial echocardiographic measurements of the inferior vena cava junction and mid tunnel in patients with an external pericardial lateral tunnel Fontan. Linear mixed model and Pearson correlation tests were used for analysis of changes in pathway size with time and body surface area. ResultsA total of 1592 echocardiographic studies from 172 patients up to 23 years after the procedure were identified. Significant enlargement of the pathway at the inferior vena cava junction and mid tunnel was observed over time (P < .0001, P < .0001, respectively). There is a strong positive correlation between increasing size of the inferior vena cava junction and increasing body surface area (R = 0.81, P < .0001). There is also a strong positive correlation between increasing size of the mid tunnel with increasing body surface area (r = 0.67, P < .0001). ConclusionsThe external pericardial lateral tunnel Fontan technique creates a Fontan pathway that enlarges into adulthood. The correlation of increasing pathway size with increasing body surface area suggests pathway growth, responding to increasing physiologic demands of somatic growth into adulthood. Further studies are needed to investigate the impact of this novel technique on Fontan physiology and long-term patient outcomes.

A disulfide bond mutant of Pseudoalteromonas porphyrae κ-carrageenase conferred improved thermostability and catalytic activity and facilitated its utilization in κ-carrageenan industrial waste residues recycling

In this study, Discovery Studio was employed to predict the potential disulfide bond mutants of the catalytic domain of Pseudoalteromonas porphyrae κ-carrageenase to improve the catalytic activity and thermal stability. The mutant N205C-G239C was identified with significantly increased catalytic activity toward κ-carrageenan substrate, with activity 4.28 times that of WT. The optimal temperature of N205C-G239C was 55 °C, 15 °C higher than that of WT. For N205C-G239C, the t1/2 value at 50 °C was 52 min, 1.41 times that of WT. The microstructural analysis revealed that the introduced disulfide bond N205C-G239C could create a unique catalytic environment by promoting favorable interactions with κ-neocarratetraose. This interaction impacted various aspects such as product release, water molecule network, thermodynamic equilibrium, and tunnel size. Molecular dynamics simulations demonstrated that the introduced disulfide bond enhanced the overall structure rigidity of N205C-G239C. The results of substrate tunnel analysis showed that the mutation led to the widening of the substrate tunnel. The above structure changes could be the possible reasons responsible for the simultaneous enhancement of the catalytic activity and thermal stability of mutant N205C-G239C. Finally, N205C-G239C exhibited the effective hydrolysis of the κ-carrageenan industrial waste residues, contributing to the recycling of the oligosaccharides and perlite.

An analytical model for the penetration of flat-nosed long rods into semi-infinite concrete targets

An analytical model is presented herein on the penetration of a flat-nosed long rod into a semi-infinite concrete target based on the previous theoretical studies and experimental observations. The nose shape of the flat-nosed long rod in deformable penetration state is assumed to be a circular arc and the length of plastic region of the long rod in hydrodynamic penetration is taken into account. The behavior of an erosive penetrator is further divided into two penetration stages (namely semi-hydrodynamic penetration and hydrodynamic penetration) and a new critical impact velocity (i.e. erosive velocity) is derived to characterize the beginning/incipient erosion in accordance with plastic wave propagation theory. According to the new theoretical considerations, the relationship of dimensionless instantaneous mushrooming head radius versus impact velocity is rewritten and the method for predicting semi-hydrodynamic penetration tunnel radius is proposed. It transpires that the present model predictions are in good agreement with available experimental results for the penetration of flat-nosed long rods into semi-infinite concrete targets in terms of penetration depth, penetration modes, penetration tunnel size, residual mass and residual length.

Arthroscopic Bone Grafting of Anterior Cruciate Ligament and Posterior Cruciate Ligament Tibial and Femoral Tunnels as a First-Stage Procedure

Recurrent multiligament knee injuries present unique challenges when performing revision ligament reconstructions. Bone tunnel widening is relatively common and considered a multifactorial condition that involves both biomechanical and biologic factors. When indicated, two-stage procedures ensure optimal revision reconstruction tunnel sizes and locations before ligament reconstruction and promote improved outcomes. Staged bone grafting is required when addressing significant tunnel widening and improper tunnel placement that puts graft incorporation at increased risk in ligament reconstructions of the knee. In this Technical Note, we describe the first stage of a two-stage procedure to address meniscus/chondral conditions, tunnel osteolysis from previous reconstructions, and tibial and femoral bone grafting for the anterior cruciate ligament and posterior cruciate ligament.

Dynamic wake conditions tailored by an active grid in the wind tunnel

Well characterized test environments are required for novel wind turbine and wind farm control concepts. Aeroelastic simulations are mostly used to model turbine aerodynamic and structural response. For wind farm control, also the wake behaviour needs to be represented, including the impacts of dynamic wind direction changes, wake meandering and the interaction of wakes with the atmospheric boundary layer. This paper shows how wake-like inflow conditions can be emulated with an active grid in a wind tunnel, exciting a broad band of turbulent scales. The artificial wake conditions can be used as inflow for an exposed model turbine. A focus is put on the meandering dynamics, which are driven by large transversal turbulence patterns in the atmospheric boundary layer. Following the conjecture of the Dynamic Wake Meandering (DWM) model, such turbulent scales must have the size of multiple rotor diameters, to impact the entire wake deficit like a passive tracer. In conventional wind tunnel experiments, such spatial scale ratios are hard to reach, since wind tunnel sizes are bounded while the model turbines must be sufficiently large to have appropriate aerodynamic scaling and instrumentation. In this work, quasi-stochastic meandering trajectories are created, using scaled Ornstein-Uhlenbeck processes. Thus, the intrinsically stochastic process of wake meandering is made repeatable. The paper focuses at a thorough characterization of the inflow conditions with both lidar and hot-wire measurements, considering wake shape and spectral features. The results show an approximately axi-symmetric Gaussian deficit, which meanders as a coherent structure while having spectral features similar to a turbine wake.

Graft Suturing Method Affects on Graft Diameter in Hamstring-Based Anterior Cruciate Ligament Reconstruction.

Various benefits of needleless suture loop techniques in anterior cruciate ligament reconstruction graft preparation have been discussed, yet their impact on graft diameter remains unexplored. We hypothesized that the suture loop technique would reduce the graft diameter compared to the conventional locking suture technique. Fifty-seven patients whose grafts were made with the Krackow stitch (group K) and 54 patients with the suture loop (group SL) were analyzed retrospectively. (1) The distal (sutured side) diameter of each anteromedial bundle and posterolateral bundle was compared to the proximal (non-sutured side) diameter, and (2) the average of the proximal and distal graft diameters in each group was calculated. In group K, 78.9% of anteromedial bundles and 40.3% of posterolateral bundles exhibited a larger distal diameter than the proximal, while in group SL, 42.6% of anteromedial bundles and 3.7% of posterolateral bundles showed a larger distal diameter. In both bundles, there were significantly fewer grafts with larger distal diameters in group SL (p < 0.001). The mean distal diameter of anteromedial bundles was smaller in group SL (6.33 ± 0.43 mm vs. 6.07 ± 0.43 mm, p < 0.005). Consequently, the distal cross-sectional area of anteromedial bundles in group SL was 8% smaller than that in group K. The use of the suture loop technique resulted in a significantly smaller distal diameter of the anteromedial bundle. This reduces the size of the tibial tunnel and may contribute to a reduction in potential damage to adjacent structures.

Computer Patient-Specific 3D Modeling and Custom-Made Guides for Revision ACL Surgery.

Revision anterior cruciate ligament reconstruction (ACLR) is a challenging surgery occurring in 3 to 24% of primary reconstructions. A meticulous planning to study the precise size and location of both femoral and tibial bone tunnels is mandatory. The aim of the study was to evaluate the intra- and interoperator differences in the decision-making process between experienced surgeons after they were asked to make preoperative planning for ACL revision reconstruction with the use of both the computed tomography (CT) scan and a three-dimensional (3D)-printed model of the knee. Data collected from 23 consecutive patients undergoing revision of ACLR for graft failure at a single institute between September 2018 and February 2020 were prospectively reviewed. The double-blinded collected data were presented to three board-certificate attending surgeons. Surgeons were asked to decide whether to perform one-stage or two-stage revision ACLR based on the evaluation of the CT scan images and the 3D-printed custom-made models at two different rounds, T0 and T1, respectively, 7 days apart one from the other. Interoperator consensus following technical mistake was 52% at T0 and 56% at T1 using the CT scans, meanwhile concordance was 95% at T0 and 94% at T1 using the 3D models. Concordance between surgeons following new knee injury was 66% at T0 and 70% at T1 using CT scans, while concordance was 96% both at T0 and T1 using 3D models. Intraoperative variability using 3D models was extremely low: concordance at T0 and T1 was 98%. McNemar test showed a statistical significance in the use of 3D model for preoperative planning (p < 0.005). 3D-printed model reliability resulted to be higher compared with CT as intraoperator surgery technique selection was not modified throughout time from T0 to T1 (p < 0.005). The use of 3D-printed models had the most impact when evaluating femoral and tibial tunnels, resulting to be a useful instrument during preoperative planning of revision ACLR between attending surgeons with medium-high workflow.

GRAFTS COMPARISON BETWEEN QUADRICEPS TENDON AUTOGRAFT VS. ALLOGRAFT FOR ANTERIOR CRUCIATE LIGAMENT REVISIOON RECONSTRUCTION: A LITERATURE REVIEW

Introduction: Anterior cruciate ligament (ACL) reconstruction is one of the most common orthopaedic surgeries performed on active people in the world. One of the most important surgical decisions is graft type for use in the reconstruction. Recently, the quadriceps tendon has gained popularity for use as a graft source for ACL reconstruction. The graft choice is broadly between an autograft or allograft. This review aims to understand the current concepts in graft comparison between quadriceps tendon autograft vs. allograft for anterior cruciate ligament revision reconstruction. Methods: This literature review study was reported following the preferred reporting items for systematic reviews and adhered to a structured review protocol. The author searched the PubMed, ScienceDirect, and British Medical Journal databases. The authors comparing selected publications reporting patient outcomes with all types of reviews or descriptions of ACL revision reconstruction and its graft being used or other related subjects. Published in English is included. The author then formulates a synthesis to support the previously determined research objectives. Results: ACL reconstruction with partial thickness soft tissue quadriceps tendon graft is a reliable option. Where there are differences in the failure rates of ACL reconstructions between allografts and autografts, these can mostly be explained by irradiated grafts. Giving sufficient radiation to achieve sterility will likely weaken grafts and make them more likely to fail; therefore, irradiating grafts is not recommended. The evidence shows no significant differences in clinical effectiveness between autografts and non-irradiated allografts. Failure rates with both grafts are now low. Discussion: The primary goals of rehabilitation after ACL reconstruction do not vary considerably based on graft type and emphasize: (1) restoration of the full range of motion, (2) normalization of quadriceps strength, (3) improvement of overall lower extremity muscle strength, and (4) re-training of movement patterns to return to pre-injury sports participation while decreasing injury risk. Achieving full motion and quadriceps strength contributes to a rapid return to normal weight bearing, gait, and activities of daily living. In the setting of revision ACL reconstruction, there are various considerations regarding graft choice due to tunnel size or position, previous usage of other grafts, and reconstructions in the other leg, which may mean that allografts would be preferred to autografts. The other population not covered sufficiently in the literature is the elite sprinting athlete, where autograft choices may be influenced by the effect of graft harvesting on their sport. However, in most cases, allograft ACL reconstruction with non-irradiated grafts is as safe but more expensive than autograft ACL reconstruction, which is preferred as it is more cost-effective. Conclusion: There is little difference in the results of ACL reconstruction with autografts or non-irradiated allografts, with any advantage being with autografts. The cost is higher with allografts. So if autografts are available, allografts are not cost-effective.

Anterior cruciate ligament femoral side retained stump technique reduces enlargement of the femoral bone tunnel after anterior cruciate ligament reconstruction

BackgroundEnlargement of the bone tunnel has become an unavoidable early complication after anterior cruciate ligament (ACL) reconstruction, whether it is a single or double-bundle ACL reconstruction. Preservation of the ACL stump in ACL reconstruction reduces enlargement of the bone tunnel. The purpose of this study was to investigate the question of whether single-bundle ACL reconstruction using the ACL femoral side retained stump technique reduces enlargement of the femoral tunnel.MethodsForty patients who underwent single-bundle reconstruction of the ACL were included in this study. The patients were categorized into a Remnant preservation group (Group R) and the Non-remnant preservation group (Group N). In the Remnant preservation group, a high-flexion femoral side retained stump technique was used intraoperatively for the establishment of the femoral side bone tunnel, and in the Non-remnant preservation group, the conventional femoral positioning method was used (we used a femoral positioning drill for localization and drilling of the femoral bone tunnel), and MRI of the operated knee joints was performed at 6 months postoperatively. We measured the internal diameter of the femoral bone tunnel at 5 mm from the intra-articular outlet of the femoral bone tunnel on an MRI scan image perpendicular to the femoral bone tunnel. The size of the tunnel was compared between the intraoperative drilling of the bone tunnel and the size of the bone tunnel at 6 months postoperatively. Postoperative clinical assessment was Lysholm score.ResultsAfter a 6-month follow-up of 40 patients, the diameter of the femoral tunnel at a distance of 5 mm from the inner opening of the femoral tunnel was 10.96 ± 0.67 mm and 10.11 ± 0.62 mm in patients of group N and group R, respectively, and the difference was statistically significant (P < 0.05).The diameter of the femoral tunnel at 6 months postoperatively in group N and group R compared to the intraoperative bone tunnel increased by 2.58 ± 0.24 mm and 1.94 ± 0.31 mm, and the difference was statistically significant (P < 0.05).The femoral tunnel enlargement rates of group N and group R were 30.94 ± 3.00% and 24.02 ± 5.10%, respectively, and the differences were significant (P < 0.05).ConclusionACL femoral side retained stump technique does not sacrifice the ideal location of the femoral tunnel and is able to preserve the possible benefits of the ACL stump: reduced femoral tunnel enlargement.

Stage I Revision ACL Reconstruction With Allograft Bone Dowels

Background: When evaluating a patient with a failed anterior cruciate ligament (ACL) reconstruction, a detailed history and physical examination is paramount. The position and size of original femoral and tibial tunnels are critical in the surgical decision-making in the setting of revision ACL reconstruction. This video presents a case of stage I revision ACL reconstruction with the use of allograft bone dowels due to increased size and poor position of original fixation tunnels. Indications: Indications for staging revision ACL reconstruction include significant tunnel osteolysis or dilation (&gt;14 mm), or any situation in which the previous bone tunnels will interfere with anatomic graft placement and fixation. Technique Description: The patient is placed in the supine position with a standard setup for knee arthroscopy, including lateral thigh post and foot stop for maintained knee flexion at 90°. After diagnostic arthroscopy, the ACL graft remnant is debrided. The femoral tunnel is then debrided and re-cannulated, followed by reaming with cannulated reamers until adequate cortical chatter is achieved, ensuring the presence of a bleeding rim of bone throughout the tunnel to confirm that the correct diameter reamer has been reached. The appropriately sized bone dowel is inserted along the guide pin until fully seated and flush with lateral wall of the notch. This process is then repeated for the tibial tunnel, accessing the tunnel from the previous incision along the medial tibia. Results: This video presents a technique to achieve adequate bone grafting of previously used tunnels that are not suitable for single-stage revision ACL reconstruction. Patients undergo second-stage revision ACL reconstruction at roughly 4 to 6 months following stage I, when bone graft has fully incorporated on radiographs. Discussion/Conclusion: Stage I revision ACL reconstruction with tunnel grafting using allograft bone dowels is a minimally invasive method of grafting previously used fixation tunnels to allow for anatomic second-stage graft placement and fixation. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Thin-airfoil aerodynamics in a rarefied gas wind tunnel: A theoretical study

We study the steady aerodynamic field and loadings about a thin flat plate placed in a wind tunnel under non-continuum conditions. Considering a two-dimensional straight tunnel configuration, the flow is driven by either density or temperature differences between the inlet and outlet tunnel reservoirs, producing a pressure gradient across the channel. Focusing on highly rarefied conditions, we derive a semi-analytic description for the gas flow field in the free-molecular limit for diffuse- and specular-wall configurations. The solution is valid at arbitrary differences between the inlet and outlet reservoirs as well as plate angles of attack α. The results are compared with direct simulation Monte Carlo calculations, indicating that the free-molecular description is valid through O(1) plate-size-based Knudsen numbers. The aerodynamic lift and drag forces are evaluated and their variations with α, reservoir conditions, and tunnel size are analyzed. At a fixed pressure ratio between the outlet and inlet reservoirs, the density-driven flow generates higher aerodynamic loads compared with its counterpart temperature-driven configuration, in line with the associated larger mass flow rate in the former. The results are discussed in light of the existing rarefied-gas description of the free-stream (non-confined) problem.

An Evaluation of Variations in the Carpal Tunnel Dimensions of Adult Subjects in a Hospital-Based Population: An Ultrasonographic Cross-Sectional Study.

Background The carpal tunnel is a groove that spans the palm as a 'U.' The ulnar and radial sides of the wrist are made up of the scaphoid tubercle and trapezium while the palmar aspect is made up of carpal bones. Our study aimed to see whether there were differences in carpal tunnel size between men and women. Material and methods The study was conducted on 65 healthy adults, 13 (20%) were males and 52 (80%) were females (both non-pregnant and pregnant). Inclusion criteria were healthy adults and bilaterally symmetrical limbs. Exclusion criteria were chronic disease, diabetes, hypertension, immunological disorders, any visible abnormalities, and a history of upper extremity pain on either side. A high-resolution ultrasound machine with a linear transducer was used to perform an ultrasound scan of the carpal tunnel. The anteroposterior dimension was measured at the midline, or along the axis of the middle finger, and the transverse diameter was measured at the midpoint of the flexor retinaculum. The cross-sectional area of the tunnel was measured at its largest diameter within the carpal tunnel. All the dimensions were measured in centimeters. Results The mean transverse diameter of the right side was 1.824 ± 0.223 cm (p-value 0.002) and of the left side was 1.742 ± 0.197 cm (p-value 0.004). The mean cross-sectionalarea of the carpal tunnel on the right side was 1.417 ± 0.379 cm2 (p-value 0.008) and on the left side was 1.306 ± 0.303 cm2(p-value 0.004), respectively. Age, sex, weight, and BMI were discussed. The carpal tunnels of females were found to be comparatively squarer and smaller than those of males. Conclusion The transverse diameter and cross-sectional area of the carpal tunnel and their correlation with carpal tunnel syndromeare predicted by age, sex, weight, and BMI. Both sexes had the same wrist ratio.

Ammonia absorption by water droplet in a small controlled atmosphere wind tunnel

The mass transfer characteristics during ammonia absorption into a sessile water droplet in a small controlled-atmosphere wind tunnel were investigated using particle tracking velocimetry (PTV) with polystyrene microspheres. The results showed that the flow field inside the droplet transformed from Marangoni convection to Rayleigh convection in the absence of gas flow. As the gas velocity increased, the drag force-induced circulation inhibited the Marangoni convection in the initial stage of the mass transfer process and Rayleigh convection in the advanced stage. However, the suppressed Marangoni convection cells recurred at high initial ammonia concentrations. Compared with the initial ammonia concentration in the wind tunnel and droplet size, the gas velocity significantly increased the gas-phase mass transfer coefficient. Furthermore, a calculation model for ammonia absorption by a moving droplet was derived based on the Colburn analogy and the two-film theory. The gas-phase mass transfer coefficients calculated using the model coincided with the experimental results. These results will help the design of water curtains.