Extension Stiffness Research Articles

Inertial and elastic properties of general composite beams

Slender composite structures can be modeled using engineering beam models with properties computed using a cross-sectional analysis program, such as VABS. These properties are given in terms of the mass matrix, stiffness matrix, and compliance matrix in a general coordinate system. The invariance of strain energy and kinetic energy is employed to rigorously transform sectional properties into different coordinate systems with parallel shifts and rotations. Additionally, the computation of commonly used inertial properties (mass center, principal inertial axes, and mass moments of inertia) from the mass matrix, and commonly used elastic properties (extension stiffness, bending stiffness, torsion stiffness, tension center, shear center, principal bending axes, principal shear axes, etc.) from the compliance matrix, is elucidated. The elastic properties are given for both the Timoshenko model and the Euler–Bernoulli model. The definitions for shear center and twist center are clarified and consistently generalized for composite beams. Isotropic homogeneous beams are used to illustrate how to relate commonly used engineering beam properties with the compliance matrix and the stiffness matrix for composite beams. Finally, engineering beam properties necessary for general-purpose aeromechanical analysis programs such as CAMRAD II are derived from the properties computed by VABS.

Towards a new frontier in wrist rehabilitation: The traction-free posture orthosis

This study presents the novel Traction-Free Posture Orthosis, designed to address wrist stiffness without the use of traditional traction methods. The orthosis employs a velcro system to stabilize the position of the wrist in flexion or extension, thereby avoiding the compression and rotational disadvantages associated with non-perpendicular traction forces. Triangular-shaped cuts in the brace allow for plastic material flexibility, ensuring movement and comfort. Significant is the absence of a traction strap, which traditionally reduces the support surface and could create pressure points leading to patient discomfort or treatment rejection. The design facilitates a wide contact surface with the hand, optimal load distribution, and the capacity to adjust dual traction straps independently, adapting to the natural wrist movement. This single-piece base orthosis offers a stable, cost-effective, and patient-friendly alternative to conventional splints. However, patients with stiffness in both flexion and extension may require two separate orthoses, potentially increasing costs and patient inconvenience. Overall, the Traction-Free Posture Orthosis represents an innovative step in wrist rehabilitation, providing a quick-to-construct, easy-to-wear solution with the promise of enhanced patient compliance and comfort.

KINEMATIC RESPONSES AND SEGMENTAL STIFFNESS OF NORMAL AND DEGENERATIVE L4/L5 MOTION SEGMENTS: FINITE ELEMENT STUDY

In this study, finite element (FE) models of an anatomical normal and a degenerated disc of L4–L5 motion segment, developed using different methodologies of volume mesh constructions, and ways of defining the spinal components’ material properties, were exercised and analyzed. The geometrics details were obtained using digitizing technique and segmentation of computed tomography (CT) scans; with material and structural properties of the spinal components defined based on the literature and greyscale values of CT images for the normal and degenerated L4–L5 motion segments, respectively. The predicted kinematic responses under five different physiological loadings in three anatomical reference planes for both models together with published data were analyzed. The predicted results correlated well within the range and in similar trends with published experimental results. The overall predicted responses showed different volume mesh constructions and the representation of spinal components’ material properties were accurate enough to predict the kinematic responses, although experimental results exhibit considerable divergence due to different experimental techniques. Both models exhibited different rotational and translation segmental stiffness in each corresponding loading configuration. The normal L4–L5 segment exhibited greatest axial torsional stiffness, and least extensional stiffness. The degenerated L4–L5 segment was least flexible (greatest stiffness) in extension and most flexible (least stiffness) in flexion. For compression, the axial stiffness of segment of normal segment was about 10% larger than that of the degenerated segment. The en-bloc efforts of all spinal components have contributed to the different nonlinear kinematic characteristics and segmental stiffness of these different L4–L5 motion segments.

Indications of Arthroscopy in the Treatment of Patellar Instability in Children.

Purpose Understanding the relevant risk factors for patellar instability and the clinical and radiographic testsnecessary to determine optimal treatment. This case series intends to evaluate arthroscopic indications in the treatment of patellar instability in children. Methods From 2013 to 2021, 33 patients (seven to 16 years of age) with 35 knees sustaining first-time dislocation with loose bodies, recurrent dislocation or subluxation, and habitual dislocation were arthroscopically operated on according to the flow chart. Periods of follow-up were two to 10 years (avg. 5.5 years). Follow-up assessment included the recurrence, complications (joint stiffness and excessive reduction), and the final function outcomes by using the Kujala score. Results Among 35 knees, there were two (5.7%) first dislocations, 30 (85.7%) recurrent dislocations, and three (8.6%) habitual dislocations, lateral release 27/35 (77.1%), medial reefing 23/35 (65.7%), reconstruction of the medial patellofemoral ligament(MPFL) 12/35 (34.3%). The major complication was a knee of extensive stiffness after medial reefing and lateral release. Recurrence was in 4/35 (11.4%) of knees, not correlated to lateral release (p=0.21), medial reefing, or reconstruction of MPFL (p=0.07); in about 23 knees of medial reefing, recurrence was significantly correlated to number of knots (p=0.045). The final functional results according to Kujala were 88-100 (avg. 95.5). Conclusions This study showed the role of arthroscopy in both medial reefing and reconstruction of MPFL in children by low recurrence rate and high Kujala score at final follow-up. There was no significant correlation between recurrence and the procedures as arthroscopic indications counted on the flow chart.

Research and Development of a 3D-Printed Dynamic Finger Flexion Orthosis for Finger Extension Stiffness-A Preliminary Study.

Finger extension stiffness is a common post-traumatic complication that results in the hand's functional impairment. In clinical practice, a dynamic splint enables the patient to stretch the affected finger independently. However, current dynamic splints have drawbacks, such as limited stretching efficacy, and interfere with the hand's functional activities. Therefore, this study aimed to develop a dynamic finger flexion orthosis capable of stretching each finger joint using additive manufacturing (AM) technology, thereby enabling hand functional activity, and analyze the clinical improvement in the range of motion (ROM). One subject with a hand fracture was recruited while undergoing a 7-week home-based rehabilitation program for the orthosis. The outcome measurements included the total active motion (TAM), the tip-to-finger distance (TPD), and the score on the Disability of Arm, Shoulder, and Hand (DASH) questionnaire. The results show that the TAM of the participant's fingers increased by 72.7 degrees on average, the TPD decreased by 3.5 cm on average, and the DASH score decreased to 9.5 points. The 7-week home-based rehabilitation program for the orthosis resulted in a 53.6% increase in the TAM on average. The developed orthosis improved hand function and enabled a more complete ROM in finger flexion.

Analyzing deformations in fiber-reinforced soft membranes undergoing axisymmetric inflation: Continuum model and experimental validation

By incorporating arrays of nearly inextensible fibers into soft membranes capable of undergoing large strains, this research explores the impact of these fibers on the deformations occurring during axisymmetric inflation. Our investigation focuses on the influence of various fiber configurations on the resulting deformed shapes. These fibers exhibit high stiffness in extension while offering minimal resistance to bending, allowing them to reorient freely upon deformation and thereby induce distinctive deformations under simple loading conditions. To predict and understand these deformations, we present a continuum model for hyperelastic membranes in generalized curvilinear coordinates, allowing for arbitrary fiber orientations, thus enhancing its adaptability to diverse configurations. Through experimental validation across multiple fiber configurations, we demonstrate the model’s accuracy in predicting deformations and showcase how the initial fiber orientation can be leveraged to create different motion patterns. We present two such motion patterns—one capable of azimuthal shear and another emphasizing extension. This study offers valuable insights for the integration of fiber reinforcement into soft morphing surfaces, with particular relevance to applications in robotics and beyond.

Cadaveric biomechanical assessment of different configurations for a novel pin and plate fixation method in distal humerus fractures

Use of dual pre-contoured plates has been accepted as the treatment of choice in distal humerus fractures despite challenges especially in very distal or highly fragmented fractures. Aiming to improve results in such instances, our newly proposed method uses several K-wires fixated by a small reconstruction plate. Drawing on the results of previous finite element studies, the current study aims to compare the stiffness of three clinically common variations of this method using biomechanical testing in cadaveric humeri. 24 samples were divided into three groups and fractures were simulated. Groups I and II used 1.5 mm K-wires in differing configurations while 2 mm wires were used in group III. All samples underwent compression, anterior and posterior bending, and torsional testing as well as failure testing. Our results indicated that Group III had significantly higher stiffness in flexion, extension, and torsion (p < 0.05). In failure, group III had the highest mean stiffness in anterior bending and torsion (861.2 N, 30.9 Nm). Based on previous and current results, this new Persian fixation method, especially when implemented using 2 mm K-wires, shows promise in achieving suitable stability and may be useful as an alternative approach in complex distal humerus fractures.

Dorsal capsule release and lateral band translocation for a stiff swan neck deformity without articular involvement.

The treatment for proximal interphalangeal joint (PIP) stiffness in extension requires extensor tenolysis, concomitant procedures to restore flexion, and intensive therapy. A stiff swan neck deformity without articular involvement is rare and the treatment is always challenging. Six patients with stiff swan neck deformities were operated between 2016 and 2023, and the outcome was analyzed retrospectively. A dorsal capsule release and radial lateral band translocation volar to the PIP joint axis were done. This translocation was maintained by a sling formed by the flexor digitorum superficialis and the free margins of the accessory collateral ligament. The range of movements in the PIP joint, visual analog scale (VAS), and functional outcomes were analyzed by the Michigan Hand Outcome Questionnaire (MHOQ) score. The mean follow-up was 49.5months (range 48-52months). The mean preoperative PIP joint extension was 8 (range 5-10) degrees of extension), and the mean preoperative PIP joint flexion was 0. All patients improved after the surgery and the mean flexion of the PIP joint at follow-up was 95 degrees; extension was 1 degree (range 0-5 degrees). The mean Michigan Hand Outcomes Questionnaire (MHOQ) score was 92 (range 90-95) and the VAS was 0. Dorsal capsule contracture release and lateral band translocation to the volar axis of the PIP joint seem to be the possibilities for correcting stiff swan neck deformity. IV, retrospective case study.

Static and fatigue cracking of thick carbon/glass hybrid composite laminates with complex wrinkle defects

This study presents an experimental investigation of cracking behavior of thick carbon/glass fiber hybrid composite laminates with manufacturing-induced ply wrinkles. Both pure glass fiber and glass/carbon fiber hybrid epoxy composite laminates are tested under static and cyclic tension. Stress–strain responses of the specimens under static tension are recorded and the failure sequences are identified. The cyclic loading is applied to the specimens under tension–tension fatigue. The stiffness degradation of the specimens is measured and the cracking events during the fatigue test are identified. The study shows that the glass/carbon fiber epoxy composite laminates first crack at a lower stress level than the pure glass ones despite their higher extension stiffness. The first cracking in the hybrid laminates occurs at the interface between different glass fiber layers while the first cracking in the pure glass laminates occurs between the rich region and the adjacent glass fiber layer in the wrinkled region. Under fatigue loading, the first cracking in hybrid laminates occurs within the carbon fiber layer while the one in the pure glass laminates occurs within the unidirectional glass fiber layer. This study also proposes a novel yet simple image difference analysis method, that by only using optical images of the specimens under fatigue loading, can accurately and efficiently pinpoint the stiffness drops at different fatigue cycles. This study provides new experimental insights into the failure of glass/carbon hybrid laminates toward a more damage-tolerant design.

Poster 327: Objectively measuring knee extension is critical when analyzing long term outcomes after an anterior cruciate ligament reconstruction

Objectives: Structural abnormalities, such as meniscus tears and chondral injuries, seen at the time of an anterior cruciate ligament (ACL) reconstruction, as well as abnormal objective measures, like knee extension stiffness, can lead to unfavorable short term outcomes following surgery. Furthermore, a lack of full knee extension in the short term has been shown to lead to a lack of full knee extension in the long term. However, long term outcomes based on knee extension are unknown as they are typically judged with subjective data only or are based on whether or not the patient had meniscus tears or chondral injuries seen at the time of surgery. The purpose of this study was to determine long term functional outcome differences after an ACL reconstruction, for those with varying structural abnormalities, based on normal and abnormal knee extension. Methods: Between 1982 and 2012, 3432 patients having an ACL reconstruction using a patellar tendon graft were enrolled into the study. Exclusion criteria included revisions, bilateral involvement, and osteoarthritis (OA) at the time of surgery. Patients were split into four groups based on structural abnormalities, normal (group 1), meniscus tear (group 2), chondral injury (group 3), and a combination of meniscus tear and chondral injury (group 4). Patients followed up for data collection and radiographs at a minimum 10 years postoperative. Abnormal knee extension was defined as more than 2° off compared to the noninvolved knee, per the International Knee Documentation Committee (IKDC) objective criteria. The IKDC subjective was collected and radiographs were graded based on the medial and lateral compartment. Additionally, short term knee extension at 2 months postoperative was compared to long term knee extension. Results: Of the 3432 patients, 899 (26%) had subjective, objective, and radiographic data at a mean 17.7 ± 6.2 years (range, 10-39) while another 898 (26%) had subjective data only at a mean 20.2 ± 7.4 years (range, 10-39). Patients with abnormal knee extension at 2 months postoperative were 6.4 times more likely to have abnormal knee extension at long term follow up ( p&lt;.001). At long term follow up, 84% of patients had normal knee extension. The rate of moderate to severe knee OA for groups 1-4 was 6%, 12%, 18%, and 25%, respectively ( p&lt;.05). The rate of moderate to severe OA and IKDC scores, when spilt based on knee extension, can be seen in table 1. Overall, patients with abnormal knee extension were 4.8 times more likely to have OA compared to those with normal knee extension. Patients with a meniscus tear were 2.1 times more likely to have OA and those with chondral injuries were 2.7 times more likely to have OA, when compared to those without a structural abnormality, p&lt;.05. Conclusions: Abnormal knee extension early after surgery can negatively affect knee extension long term as those that are lacking motion early rarely have normal knee extension long term. Abnormal knee extension long term can lead to lower subjective scores and higher rates of OA when compared to those with normal knee extension. A loss of knee extension long term results in more negative outcomes than meniscus tears or chondral injuries. Objectively measuring knee extension long term after surgery can help explain positive and negative outcomes for patients, regardless of their meniscus or chondral status at the time of surgery. [Table: see text]

Radial versus dorsal plating for trapeziometacarpal arthrodesis: a comparative biomechanical study.

Trapeziometacarpal arthrodesis is used for the treatment of advanced arthritis. Insufficient stabilization of the joint may lead to nonunion or hardware problems after arthrodesis. The purpose of this study was to compare the biomechanical properties of dorsal versus radial plate fixation of the trapeziometacarpal joint in ten pairs of fresh-frozen cadaveric hands. The biomechanical performance of each group was measured for stiffness in extension and flexion and load to failure using cantilever bending tests. The stiffness in extension was lower in the dorsally positioned group than in the radially positioned group (12.1 versus 15.2 N/mm, respectively). Load to failure was comparable between both groups (53.9 versus 50.9 N, respectively). A radially positioned locking plate for trapeziometacarpal arthrodesis may be biomechanically advantageous.

A Multi-DoF Exoskeleton Haptic Device for the Grasping of a Compliant Object Adapting to a User's Motion Using Jamming Transitions

In the recently growing field of virtual reality, the virtual grasping sensation remains in its infancy, and the discrepancy between real and virtual grasping has become a problem. This article develops a new haptic glove that presents the sensation of different types of grasping (e.g., power/precision/intermediate grasping) a compliant object. To this end, we develop an exoskeleton that fixes the movements of fingers to present a braking force and a flexible pad that reproduces a wide range of stiffness. By applying the “string jamming mechanism,” our exoskeleton has functions that existing devices do not. In that, it constrains the motion of finger extension/flexion and adduction/abduction with only one actuator and presents the braking force to all surfaces of the finger. In addition, we propose a lightweight and compact variable-stiffness pad that reproduces an extensive stiffness range based on the layer jamming technique. We conducted experiments to evaluate the mechanical performance of the prototype integrating the exoskeleton and the variable-stiffness pad and demonstrated the usefulness of the proposed glove.

Biomechanical evaluation of effects of percutaneous cement discoplasty and percutaneous cement interbody fusion on spinal stability

To investigate the effects of percutaneous cement discoplasty (PCD) and percutaneous cement interbody fusion (PCIF) on spinal stability by in vitro biomechanical tests. Biomechanical test was divided into intact (INT) group, percutaneous lumbar discectomy (PLD) group, PCD group, and PCIF group. Six specimens of L 4, 5 (including vertebral bodies and intervertebral discs) from fresh male cadavers were taken to prepare PLD, PCD, and PCIF specimens, respectively. Before treatment and after the above treatments, the MTS multi-degree-of-freedom simulation test system was used to conduct the biomechanical test. The intervertebral height of the specimen was measured before and after the axial loading of 300 N, and the difference was calculated. The range of motion (ROM) and stiffness of the spine in flexion, extension, left/right bending, and left/right rotation under a torque of 7.5 Nm were calculated. After axial loading, the change of intervertebral height in PLD group was more significant than that in other three groups ( P<0.05). Compared with INT group, the ROM in all directions significantly increased and the stiffness significantly decreased in PLD group ( P<0.05). Compared with INT group, the ROM of flexion, extension, and left/right rotation in PCD group significantly increased and the stiffness significantly decreased ( P<0.05); compared with PLD group, the ROM of flexion, extension, and left/right bending in PCD group significantly decreased and the stiffness significantly increased ( P<0.05). Compared with INT group, ROM of left/right bending in PCIF group significantly decreased and stiffness significantly increased ( P<0.05); compared with PLD group, the ROM in all directions significantly decreased and the stiffness significantly increased ( P<0.05); compared with PCD group, the ROM of flexion, left/right bending, and left/right rotation significantly decreased and stiffness significantly increased ( P<0.05). Both PCD and PCIF can provide good biomechanical stability. The former mainly affects the stiffness in flexion, extension, and bending, while the latter is more restrictive on lumbar ROM in all directions, especially in bending and rotation.

Quantitative measurement of resistance force and subsequent attenuation during passive isokinetic extension of the wrist in patients with mild to moderate spasticity after stroke

BackgroundSpasticity is evaluated by measuring the increased resistance to passive movement, primarily by manual methods. Few options are available to measure spasticity in the wrist more objectively. Furthermore, no studies have investigated the force attenuation following increased resistance. The aim of this study was to conduct a safe quantitative evaluation of wrist passive extension stiffness in stroke survivors with mild to moderate spastic paresis using a custom motor-controlled device. Furthermore, we wanted to clarify whether the changes in the measured values could quantitatively reflect the spastic state of the flexor muscles involved in the wrist stiffness of the patients.Materials and methodsResistance forces were measured in 17 patients during repetitive passive extension of the wrist at velocities of 30, 60, and 90 deg/s. The Modified Ashworth Scale (MAS) in the wrist and finger flexors was also assessed by two skilled therapists and their scores were averaged (i.e., average MAS) for analysis. Of the fluctuation of resistance, we focused on the damping just after the peak forces and used these for our analysis. A repeated measures analysis of variance was conducted to assess velocity-dependence. Correlations between MAS and damping parameters were analyzed using Spearman’s rank correlation.ResultsThe damping force and normalized value calculated from damping part showed significant velocity-dependent increases.There were significant correlations (ρ = 0.53–0.56) between average MAS for wrist and the normalized value of the damping part at 90 deg/s. The correlations became stronger at 60 deg/s and 90 deg/s when the MAS for finger flexors was added to that for wrist flexors (ρ = 0.65–0.68).ConclusionsThis custom-made isokinetic device could quantitatively evaluate spastic changes in the wrist and finger flexors simultaneously by focusing on the damping part, which may reflect the decrease in resistance we perceive when manually assessing wrist spasticity using MAS.Trial registration UMIN Clinical Trial Registry, as UMIN000030672, on July 4, 2018

Spinopelvic Mobility Pattern and Acetabular Anteversion in Stiff Hips With Ankylosing Spondylitis After Total Hip Arthroplasty

BackgroundFused hips with spine stiffness in ankylosing spondylitis (AS) reduce spinopelvic mobility. We aimed to assess spinopelvic mobility pattern and acetabular anteversion in AS after total hip arthroplasty (THA). Material and methodsNinety-four stiff hips in 58 AS individuals (mean age: 37.05) who underwent THA between 2012 and 2018 with a modified lateral approach were included. Twenty-three hips were fused, and 71 hips had mean flexion of 37.67°. Pelvic tilt, pelvic inclination, sacral slope (SS), and lumbar lordosis were correlated with THA, and functional outcomes were assessed at 34.6-month mean follow-up. ResultsThirty-seven had a stuck sitting pattern with stuck standing seen in 4 individuals. SS standing before and after THA were 25.08° and 27.30°. SS sitting was 8.99° compared to 16.80°. SS from sitting to standing was reduced (17.7°) in 17 individuals. Spine stiffness in extension was seen in 4 out of 37. Mean acetabular inclination after THA was 42.67°, and acetabular anteversion was 17.48°. Flexion after THA improved to mean 98.47°. Changes in SS from sitting to standing were correlated with THA (r-value: 0.93, P-value: .0001). The Harris Hip Score improved from 25.31 to 82.39 (P-value <.05), and the mean 12-item Short Form Survey at review was 52.18 and 59.55 (physical and mental components). The mean Western Ontario and Mc Master Universities Arthritis Index score was 17.56. ConclusionsSpinopelvic mobility change was <10° after THA in AS, stuck sitting was seen in 37 of 58 (63.8%), and stuck standing was seen in 4 of 58 (6.9%), including spine stiffness in flexion or extension. Acetabular anteversion assessed was 17.48° (standard deviation: 4.41), with significant functional improvement. Level of EvidenceLevel 4.

Are rotational passive stiffness and translational passive stiffness correlated? A porcine in vitro study

BackgroundQualitative clinical assessments of spinal stiffness have been demonstrated to show moderate correlations with one-another. We hypothesized that these correlations would improve in an in vitro model of the functional spinal unit. If the stiffness of spinal units are different across loading regimes (e.g. flexion-extension versus shear), then it may provide one explanation as to the variability in findings from clinical assessments, since these tests tend not to discriminate rotational and translational degrees-of-freedom. Therefore, the purpose of this investigation was to quantify the relationships between rotational and translational stiffness measures in vitro. MethodsForty-eight porcine cervical spine functional units were used in this investigation (20 C3-C4, 28 C5-C6). While under constant 300 N compressive load, range-of-motion tests for both flexion-extension (± 8 Nm, 0.5 deg./s) and anteroposterior shear (± 400 N, 0.2 mm/s) were conducted, to quantify moment-angle and force-deflection curves. Representative stiffness values were then obtained for flexion, extension, anterior shear, and posterior shear using segmented regression. The correlation matrix between these four measures was then used to explore their potential relationships. FindingsOf the six correlations conducted, only the relationship between posterior shear and extension stiffness was statistically significant (p = 0.014), despite featuring a low correlation coefficient (R2 = 0.123). InterpretationThe poor correlations between stiffness metrics in this study supports the disparate findings of tissue stiffness in vivo. Results from this investigation suggest that clinicians should be cognizant of which degrees-of-freedom they are assessing in the spine, as their stiffness values vary independently.

Assessment of the SARS-CoV-2 and comorbidities impact on some parameters of the cardiovascular system in intensive care patients

Modern prospective studies report that an increase in the stiffness of the vascular wall is a predictor of diseases of the cardiovascular system (CVS) due to impaired shock-absorbing function of the main arteries. Shock absorption (reduction of fluctuations) of the walls of the arteries is determined by their extensibility (stiffness) and elasticity; it is indispensable in order to smooth out periodic systolic waves of blood flow and reduce the damaging effect of the pulse wave on the vascular wall. The novel coronavirus infection SARS-CoV-2 predominantly affects the lung tissue, but it can also impact the cardiovascular system. Numerous studies support the development of myocarditis, heart failure, arrhythmias, and thrombotic complications in patients hospitalized for COVID-19.

Significant risk of arthrolysis after simultaneous anterior cruciate ligament reconstruction and treatment of dislocated bucket-handle meniscal tear

IntroductionPostoperative stiffness is a feared complication after anterior cruciate ligament (ACL) reconstruction. In case of associated dislocated bucket-handle meniscal tear (BHMT), reduction is urgent, with ligament reconstruction in the same surgical step. HypothesisTreatment of associated dislocated BHMT in ACL reconstruction incurs increased risk of arthrolysis for stiffness in flexion and/or extension. Material and methodsA retrospective exposure/non-exposure study included 208 patients undergoing ACL reconstruction between January 2009 and December 2018. Those showing dislocated medial or lateral BHMT at surgery (group A) were compared versus those free of meniscal lesions (group B). The main objective was to assess the risk of surgical revision for arthrolysis within 12 months. Group A included 69 patients: 40 male (58%), 29 female (42%); mean age, 29.0±11.2 years. Group B included 139 patients: 68 male (49%), 71 female (51%); mean age, 30.0±10.4 years. Patients were classified according to age of ACL tear, as acute (<6 weeks), subacute (6 weeks to 6 months), or chronic (>6 months). ResultsRisk of revision surgery for arthrolysis was greater in Group A than in Group B, with 7 (10.1%) and 4 (2.9%) cases respectively (p=0.044), with 12-month arthrolysis-free survival of 89.7% (95% CI, 82.7–97.2) and 97.1% (95% CI, 94.3–99.9) respectively (p=0.023). Stiffness in flexion and extension was more frequent in Group A at 6 weeks and at 6 months (p>0.05). Risk of arthrolysis did not significantly differ according to accident-to-surgery time in the overall series (p=0.421) or specifically in Group A (p=0.887). The BHMT was sutured in 39 cases (56.5%), including 3 failures (7.7%) at 12 months’ follow-up. Arthrolysis was required in 6 patients treated by meniscal suture (15.4%) and just 1 patient treated by meniscectomy (3.3%) (p=0.128). ConclusionThe present study confirmed increased risk of surgical revision for arthrolysis after ACL reconstruction in case of dislocated BHMT treated in the same surgical step. Age of ACL tear and type of BHMT treatment (suture or meniscectomy) showed no impact on postoperative stiffness. Level of evidenceIV, retrospective exposure/non-exposure cohort study.

Pour une amélioration de la prise en charge du diabète des résidents en EHPAD

Postoperative stiffness is a feared complication after anterior cruciate ligament (ACL) reconstruction. In case of associated dislocated bucket-handle meniscal tear (BHMT), reduction is urgent, with ligament reconstruction in the same surgical step.Treatment of associated dislocated BHMT in ACL reconstruction incurs increased risk of arthrolysis for stiffness in flexion and/or extension.A retrospective exposure/non-exposure study included 208 patients undergoing ACL reconstruction between January 2009 and December 2018. Those showing dislocated medial or lateral BHMT at surgery (group A) were compared versus those free of meniscal lesions (group B). The main objective was to assess the risk of surgical revision for arthrolysis within 12 months. Group A included 69 patients: 40 male (58%), 29 female (42%); mean age, 29.0 ± 11.2 years. Group B included 139 patients: 68 male (49%), 71 female (51%); mean age, 30.0 ± 10.4 years. Patients were classified according to age of ACL tear, as acute (< 6 weeks), subacute (6 weeks to 6 months), or chronic (> 6 months).Risk of revision surgery for arthrolysis was greater in Group A than in Group B, with 7 (10.1%) and 4 (2.9%) cases respectively (p = 0.044), with 12-month arthrolysis-free survival of 89.7% (95% CI, 82.7–97.2) and 97.1% (95% CI, 94.3–99.9) respectively (p = 0.023). Stiffness in flexion and extension was more frequent in Group A at 6 weeks and at 6 months (p > 0.05). Risk of arthrolysis did not significantly differ according to accident-to-surgery time in the overall series (p = 0.421) or specifically in Group A (p = 0.887). The BHMT was sutured in 39 cases (56.5%), including 3 failures (7.7%) at 12 months’ follow-up. Arthrolysis was required in 6 patients treated by meniscal suture (15.4%) and just 1 patient treated by meniscectomy (3.3%) (p = 0.128).The present study confirmed increased risk of surgical revision for arthrolysis after ACL reconstruction in case of dislocated BHMT treated in the same surgical step. Age of ACL tear and type of BHMT treatment (suture or meniscectomy) showed no impact on postoperative stiffness.IV, retrospective exposure/non-exposure cohort study.

Biomechanical Analysis of Sagittal Plane Pin Placement Configurations for Pediatric Supracondylar Humerus Fractures

Anterior to posterior (AP) pinning is the recommended sagittal pin configuration in divergent lateral entry coronal pinning of pediatrics supracondylar fractures. However, there was still a lack of evidence regarding alternative sagittal pins configurations. We aimed to compare the construct stiffness of alternative sagittal pin configurations by using synthetic bone models. Sixty synthetic pediatric humeri were osteotomized to create a supracondylar fracture. After the fracture reduction, all specimens were fixed in the coronal plane with divergent lateral entry pin configurations in four different patterns in the sagittal plane: AP, crossed, divergent and parallel sagittal pin configuration. Each configuration was tested with five loading patterns. The AP sagittal pin had significantly lower construct stiffness than the divergent (p = 0.003) and the parallel sagittal pin configuration (p = 0.005) in external rotation loading tests. The divergent sagittal pin had the highest construct stiffness in extension, valgus, and external rotation loads, but the parallel sagittal pin had lower construct stiffness under extension load than the divergent and crossed sagittal pin configurations. The divergent sagittal pin configuration provides greater construct stiffness than other sagittal pin configurations due to the maximal pin spreading distance at the fracture site and the pin angle lock mechanism.