Developing and Validating a Model of Humeral Stem Primary Stability, Intended for In Silico Clinical Trials

In silico clinical trials (ISCT) can contribute to demonstrating a device's performance via credible computational models applied on virtual cohorts. Our purpose was to establish the credibility of a model for assessing the risk of humeral stem loosening in total shoulder arthroplasty, based on a twofold validation scheme involving both benchtop and clinical validation activities, for ISCT applications. A finite element model computing bone-implant micromotion (benchtop model) was quantitatively compared to a bone foam micromotion test (benchtop comparator) to ensure that the physics of the system was captured correctly. The model was expanded to a population-based approach (clinical model) and qualitatively evaluated based on its ability to replicate findings from a published clinical study (clinical comparator), namely that grit-blasted stems are at a significantly higher risk of loosening than porous-coated stems, to ensure that clinical performance of the stem can be predicted appropriately. Model form sensitivities pertaining to surgical variation and implant design were evaluated. The model replicated benchtop micromotion measurements (52.1 ± 4.3 µm), without a significant impact of the press-fit ("Press-fit": 54.0 ± 8.5 µm, "No press-fit": 56.0 ± 12.0 µm). Applied to a virtual population, the grit-blasted stems (227 ± 78µm) experienced significantly larger micromotions than porous-coated stems (162 ± 69µm), in accordance with the findings of the clinical comparator. This work provides a concrete example for evaluating the credibility of an ISCT study. By validating the modeling approach against both benchtop and clinical data, model credibility is established for an ISCT application aiming to enrich clinical data in a regulatory submission.

A risk and credibility framework for in silico clinical trials of medical devices

BACKGROUND AND OBJECTIVE

The use of in silico clinical trials (ISCTs) to generate clinically-relevant data on new medical devices is an emerging area of regulatory research. Interest in ISCTs stems from recognized challenges in acquiring sufficient clinical data and the continued maturation of in silico technologies. There is currently no guidance in place for evaluating the credibility of ISCT applications. The objective of this work was to adapt an existing risk-based credibility framework specifically for ISCT applications, and demonstrate its utility on a contemporary case study.

METHODS

Expanding on guidance currently in place for assessing the risk of traditional modeling applications of medical devices and demonstrating model credibility through benchtop validation activities, a framework is proposed to (1) evaluate the model risk for ISCT applications based on the independent factors of scope, coverage, and severity, and (2) assess the credibility of clinical validation activities based on consideration of the clinical comparator, the validation model, the agreement between the two, and the applicability of the clinical validation activities to the ISCT application.

RESULTS

The resulting framework spans across the range of ISCT applications that may be envisioned, as well as the variety of clinical datasets that can be used to demonstrate model credibility. Credibility factors reflect the expected clinical variability in the validation comparator and validation model, the statistical power of the comparator, the rigor of agreement between the comparator and model in terms of both inputs and outputs, and the overall similarity of the device in the validation activities to the device within the intended ISCT. When applied to a high-risk case study, the framework reveals that planned clinical validation activities require additional rigor in order to achieve the credibility targets, enabling an assessment of the validation effort relative to the potential benefit prior to investing in the validation studies.

DISCUSSION

An objective and risk-based framework for establishing credibility requirements for ISCT applications is a critical step in advancing ISCT from theory to practice. The proposed framework enforces that appropriate validation of ISCT applications requires evidence that the intended clinical environment is accurately represented. The framework will contribute to reducing uncertainty amongst technical, clinical, and regulatory constituents on ISCT applications, and promote rational adoption.

Identifying the patient harms to include in an in silico clinical trial

BACKGROUND AND OBJECTIVE

Clinical trials represent a crucial step in the development and approval of medical devices. These trials involve evaluating the safety and efficacy of the device in a controlled setting with human subjects. However, traditional clinical trials can be expensive, time-consuming, and ethically challenging. Augmenting clinical trials with data from computer simulations, so called in silico clinical trials (ISCT), has the potential to address these challenges while satisfying regulatory requirements. However, determination of the patient harms in scope of an ISCT is necessary to ensure all harms are sufficiently addressed while maximizing the utility of the ISCT. This topic is currently lacking guidance. The objective of this work is to propose a general method to determine which patient harms should be included in an ISCT for a regulatory submission.

METHODS

The proposed method considers the risk associated with the harm, the impact of the device on the likelihood of occurrence of the harm and the technical feasibility of evaluating the harm via ISCT. Consideration of the risk associated with the harm provides maximum clinical impact of the ISCT, in terms of focusing on those failure modes which are most relevant to the patient population. Consideration of the impact of the device on a particular harm, and the technical feasibility of modeling a particular harm supports that the technical effort is devoted to a problem that (1) is relevant to the device in question, and (2) can be solved with contemporary modeling techniques.

RESULTS AND CONCLUSIONS

As a case study, the proposed method is applied to a total shoulder replacement humeral system. With this framework, it is hoped that a consistent approach to scoping an ISCT can be adopted, supporting investment in ISCT by the industry, enabling consistent review of the ISCT approach across device disciplines by regulators, and providing maximum impact of modeling technologies in support of devices to improve patient outcomes.

A multicentric multimodal in vivo microscopy MRI study of bipolar disorder reveals axonal loss and demyelination

Introduction

Bipolar disorder has been repeatedly associated with abnormalities of white matter. However, DTI is intrinsically limited and the precise cellular mechanisms that underlie these alterations remains unknown.

Objectives

Our aim was to investigate microscopical characteristics of white matter using MRI in patients with bipolar and healthy controls.

Methods

77 patients and 71 controls from 3 sites had a T1 structural MRI, a multi-shell HARDI MRI and at one site with a T1-weighted VFA-SPGR acquisition, and a T2 MSME acquisition. The volume fraction and the orientation dispersion was extracted using NODDI from DW images in each site. Myelin Water Fraction was extracted in 33 patients and 36 controls to probe myelin characteristics. White matter bundles were reconstructed using deterministic tractography. Statistical analyses were performed after harmonization by the ComBat algorithm and controlled for age, gender and handedness.

Results

We found significant lower axonal density in patients along the short fibers of the left cingulum, the left anterior arcuate and the left inferior fronto-occipital fasciculus. We found lower mean MWF in patients along the short fibers of the right cingulum, the left inferior fronto-occipital fasciculus, the left anterior arcuate and the splenium of the corpus callosum. We found higher mean orientation dispersion in patients only along the left uncinate fasciculus.

Conclusions

We report alterations of limbic and inter-hemispheric white matter tracts in patients with bipolar disorder reflecting axonal loss, demyelination and architecture alterations. These results contribute to better capture the plurality of the mechanisms involved in bipolar disorder that cannot be deciphered with classical diffusion MRI.

Disclosure

No significant relationships.

Computational analysis of subscapularis tears and pectoralis major transfers on muscular activity

BACKGROUND

Pectoralis major is the most common muscle transfer procedure to restore joint function after subscapularis tears. Limited information is available on how the neuromuscular system adjusts to the new configuration, which could explain the mixed outcomes of the procedure. The purpose of this study is to assess how muscles activation patterns change after pectoralis major transfers and report their biomechanical implications.

METHODS

We compare how muscle activation change with subscapularis tears and after its treatment by pectoralis major transfers of the clavicular, sternal, or both these segments, during three activities of daily living and a computational musculoskeletal model of the shoulder.

FINDINGS

Our results indicate that subscapularis tears require a compensatory activation of the supraspinatus and is accompanied by a reduced co-contraction of the infraspinatus, both of which can be partially recovered after transfer. Furthermore, although the pectoralis major acts asynchronously to the subscapularis before the transfer, its activation pattern changes significantly after the transfer.

INTERPRETATION

The capability of a transferred muscle segment to activate similarly to the intact subscapularis is found to be dependent on the given motion. Differences in the activation patterns between intact subscapularis and the segments of pectoralis major may explain the difficulty in adapting psycho-motor patterns during the rehabilitation period. Thereby, rehabilitation programs could benefit from targeted training on specific motion and biofeedback programs. Finally, the condition of the anterior deltoid should be considered to improve joint function.

[Enriching in vivo clinical trials with in silico models for orthopedic implants]

Clinical trials are used by the medical device industry to confirm products safety, performance, and clinical benefits. Traditional clinical studies typically follow a limited number of volunteers, which prevents capturing the full breath of patient demographics and implant use. New tools are required to overcome the limitations of traditional trials while fulfilling increasingly demanding regulatory requirements. Computer simulations have the potential to enrich traditional clinical trials with so called in silico clinical trials (ISCT) by providing data on a much broader spectrum of patients, clinical conditions and implant configurations. The historical use of simulation in the orthopedic device industry is described here to explain how it is now technically possible to model virtual populations. We also discuss the multiple benefits of such a translational research approach for the patients, healthcare systems, and manufacturers, but also the challenges to overcome. A more detailed version is available in English [1].

Influence of rotator cuff integrity on loading and kinematics before and after reverse shoulder arthroplasty

Reverse Shoulder Arthroplasty has become a very common procedure for shoulder joint replacement, even for scenarios where an anatomical reconstruction would traditionally be used. Our hypothesis is that implanting a reverse prosthesis with a functional rotator cuff may lead to higher joint reaction force (JRF) and have a negative impact on the prosthesis. Available motion capture data during anterior flexion was input to a finite-element musculoskeletal shoulder model, and muscle activations were computed using inverse dynamics. Simulations were carried out for the intact joint as well as for various types of rotator cuff tears: superior (supraspinatus), superior-anterior (supraspinatus and subscapularis), and superior-posterior (supraspinatus, infraspinatus and teres minor). Each rotator cuff tear condition was repeated after shifting the humerus and the glenohumeral joint center of rotation to represent the effect of a reverse prosthesis. Changes in compressive, shear, and total JRF were analyzed. The model compared favorably to in vivo JRF measurements, and existing clinical and biomechanical knowledge. Implanting a reverse prosthesis with a functional rotator cuff or with an isolated supraspinatus tear led to more than 2 times higher compressive JRF than with massive rotator cuff tears (superior-anterior or superior-posterior), while the shear force remained comparable. The total JRF increased more than 1.5 times. While a lower shear to compressive ratio may reduce the risk of glenosphere loosening, higher JRF might increase the risk for other failure modes such as fracture or polyethylene wear of the reverse prosthesis.

In Silico Clinical Trials in the Orthopedic Device Industry: From Fantasy to Reality?

The orthopedic device industry relies heavily on clinical evaluation to confirm the safety, performance, and clinical benefits of its implants. Limited sample size often prevents these studies from capturing the full spectrum of patient variability and real-life implant use. The device industry is accustomed to simulating benchtop tests with numerical methods and recent developments now enable virtual "in silico clinical trials" (ISCT). In this article, we describe how the advancement of computer modeling has naturally led to ISCT; outline the potential benefits of ISCT to patients, healthcare systems, manufacturers, and regulators; and identify how hurdles associated with ISCT may be overcome. In particular, we highlight a process for defining the relevant patient risks to address with ISCT, the utility of a versatile software pipeline, the necessity to ensure model credibility, and the goal of limiting regulatory uncertainty. By complementing-not replacing-traditional clinical trials with computational evidence, ISCT provides a viable technical and regulatory strategy for characterizing the full spectrum of patients, clinical conditions, and configurations that are embodied in contemporary orthopedic implant systems.

Chronic Pseudoparalysis Needs to Be Distinguished From Pseudoparesis: A Structural and Biomechanical Analysis

BACKGROUND

Chronic pseudoparalysis is generally defined as the inability to actively elevate the arm above 90° with free passive range of motion and no neurological deficits. It has been suggested that this arbitrary cutoff needs to be refined.

PURPOSE

To analyze whether there are structural and biomechanical differences in patients with chronic pseudoparalysis and those with chronic pseudoparesis.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

In this retrospective study, 50 patients with chronic massive rotator cuff tears (mRCTs; ≥2 tendons) and free passive and active scapular plane abduction <90° were divided into 2 groups: pseudoparalysis group (n = 24; active scapular plane abduction, <45°) and pseudoparesis group (n = 26; active scapular plane abduction, >45° and <90°). Radiographic measurements included the critical shoulder angle, acromiohumeral distance, posterior acromial tilt, anterior and posterior acromial coverages, and posterior acromial height on outlet views. Measurements on magnetic resonance imaging (MRI) included fatty infiltration of the rotator cuff muscles, anterior (subscapularis) and posterior (infraspinatus/teres minor) tear extensions, and global (anterior + posterior) tear extension in the parasagittal plane. A published musculoskeletal model was used to simulate the effect of different mRCTs on the muscle force required for scapular plane abduction.

RESULTS

Plain radiographs revealed no differences between patients with chronic pseudoparalysis and those with pseudoparesis. MRI assessment showed significant differences between patients with chronic pseudoparalysis and those with pseudoparesis with respect to fatty infiltration of the subscapularis (2.9 vs 1.6; P < .001) and infraspinatus (3.6 vs 3.0; P < .001) muscles, and anterior (-23° vs 4°; P < .001), posterior (-23° vs -14°; P = .034), and global rotator cuff (225° vs 190°; P < .001) tear extensions. The anterior tear extension in patients with chronic pseudoparalysis always involved more than 50% of the subscapularis, which was associated with an odds ratio of 5 for inability to actively abduct more than 45°. The biomechanical model was unable to find a combination of muscles that could balance the arm in space when the tear extended beyond the supraspinatus and the cranial subscapularis.

CONCLUSION

This study confirms that chronic pseudoparalysis and pseudoparesis are associated with different structural lesions. In the setting of a chronic mRCT, involvement of more than 50% of the subscapularis tendon with fatty infiltration of stage 3 is associated with pseudoparalysis of active scapular plane abduction <45°. The key function of the subscapularis was confirmed in the biomechanical model.

Differentiation between mechanically loose and fixed press-fit implants using quantitative acoustics and load self-referencing: A phantom study on shoulder prostheses in polyurethane foam

This study proposes to use cross-interface quantitative acoustics (ci-qA) and load self-referencing (LSR) to assess implant stability in a radiation-free, inexpensive, rapid, and quantitative manner. Eight bone analog specimens, made from polyurethane foam, were implanted with a cementless stemless shoulder implant—first in a fixed and later in a loose configuration—and measured using ci-qA under two load conditions. The loose implants exhibited higher micromotion and lower pull-out strength than their stable counterparts, with all values falling within the range of reported reference values. All acoustic characteristics differentiated between loose and fixed implants (maximum area-under-curve AUC = 1.0 for mean total signal energy, AUC = 1.0 for mean total signal energy ratio, AUC = 0.8 for harmonic ratio, and AUC = 0.92 for load self-referencing coefficient). While these results on bone substitute material will need to be confirmed on real bone specimen, ci-qA could ultimately facilitate the assessment of primary stability during implantation surgery and avoid unnecessary revision through quantitative evaluation of secondary stability during follow-up.

Cerebellar parcellation in schizophrenia and bipolar disorder

OBJECTIVE

The cerebellum is involved in cognitive processing and emotion control. Cerebellar alterations could explain symptoms of schizophrenia spectrum disorder (SZ) and bipolar disorder (BD). In addition, literature suggests that lithium might influence cerebellar anatomy. Our aim was to study cerebellar anatomy in SZ and BD, and investigate the effect of lithium.

METHODS

Participants from 7 centers worldwide underwent a 3T MRI. We included 182 patients with SZ, 144 patients with BD, and 322 controls. We automatically segmented the cerebellum using the CERES pipeline. All outputs were visually inspected.

RESULTS

Patients with SZ showed a smaller global cerebellar gray matter volume compared to controls, with most of the changes located to the cognitive part of the cerebellum (Crus II and lobule VIIb). This decrease was present in the subgroup of patients with recent-onset SZ. We did not find any alterations in the cerebellum in patients with BD. However, patients medicated with lithium had a larger size of the anterior cerebellum, compared to patients not treated with lithium.

CONCLUSION

Our multicenter study supports a distinct pattern of cerebellar alterations in SZ and BD.

A larger critical shoulder angle requires more rotator cuff activity to preserve joint stability

Shoulders with rotator cuff tears (RCT) tears are associated with significantly larger critical shoulder angles (CSA) (RCT CSA = 38.2°) than shoulders without RCT (CSA = 32.9°). We hypothesized that larger CSAs increase the ratio of glenohumeral joint shear to joint compression forces, requiring substantially increased compensatory supraspinatus loads to stabilize the arm in abduction. A previously established three dimensional (3D) finite element (FE) model was used. Two acromion shapes mimicked the mean CSA of 38.2° found in patients with RCT and that of a normal CSA (32.9°). In a first step, the moment arms for each muscle segment were obtained for 21 different thoracohumeral abduction angles to simulate a quasi-static abduction in the scapular plane. In a second step, the muscle forces were calculated by minimizing the range of muscle stresses able to compensate an external joint moment caused by the arm weight. If the joint became unstable, additional force was applied by the rotator cuff muscles to restore joint stability. The model showed a higher joint shear to joint compressive force for the RCT CSA (38.2°) for thoracohumeral abduction angles between 40° and 90° with a peak difference of 23% at 50° of abduction. To achieve stability in this case additional rotator cuff forces exceeding physiological values were required. Our results document that a higher CSA tends to destabilize the glenohumeral joint such that higher than normal supraspinatus forces are required to maintain modeled stability during active abduction. This lends strong support to the concept that a high CSA can induce supraspinatus (SSP) overload. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:961-968, 2016.

Influence of resection geometry on fracture risk in the treatment of femoroacetabular impingement: a finite element study

BACKGROUND

A fracture is the most serious complication of surgical resection of the femoral head-neck junction in the treatment of cam-type femoroacetabular impingement (FAI).

PURPOSE

To investigate the influence of resection length, width, and depth on postoperative fracture risk in activities of daily living.

STUDY DESIGN

Descriptive laboratory study.

METHODS

The femoral anatomy used for the finite element model was based upon a publicly available standardized model. For descriptive validation, the fracture location was compared with radiographs of patients who had suffered from a femoral neck fracture after surgical treatment of FAI in our institution. Additionally, a 2-part quantitative validation against previously published experimental data was performed. To simulate surgery, round resections were made in which length and width were varied at 10%, 20%, and 30%. The fracture loads were compared with published in vivo loads measured during activities of daily living with telemetric hip implants.

RESULTS

Validation showed that the model predicted fracture locations comparable with clinical cases and fracture loads within published experimental values. Femoral fracture loads were 325% more sensitive to resection deepening and 70% more sensitive to widening than lengthening.

CONCLUSION

Although resection depth is the most important determinant of bone resistance, it should be considered in combination with resection length and width. Even a resection depth as low as 10% may lead to a fracture in case of stumbling.

CLINICAL RELEVANCE

We show that for resection depths of 20% or less and resection length of less than 35% of the femoral neck, normal activities of daily living are safe. Resection widths typically achieved in practice did not induce fractures during activities of daily living. Patients who have undergone surgical resection should be counseled on how to try to avoid stumbling.

Correlation of psychomotor findings and the ability to partially weight bear

Background

Partial weight bearing is thought to avoid excessive loading that may interfere with the healing process after surgery of the pelvis or the lower extremity. The object of this study was to investigate the relationship between the ability to partially weight bear and the patient's psychomotor skills and an additional evaluation of the possibility to predict this ability with a standardized psychomotor test.

Methods

50 patients with a prescribed partial weight bearing at a target load of 15 kg following surgery were verbally instructed by a physical therapist. After the instruction and sufficient training with the physical therapist vertical ground reaction forces using matrix insoles were measured while walking with forearm crutches. Additionally, psychomotor skills were tested with the Motorische Leistungsserie (MLS). To test for correlations Spearman's Rank correlation was used. For further comparison of the two groups a Mann-Withney test was performed using Bonferroni correction.

Results

The patient's age and body weight significantly correlated with the ability to partially weight bear at a 15 kg target load. There were significant correlations between several subtests of the MLS and ground reaction forces measured while walking with crutches. Patients that were able to correctly perform partial weight bearing showed significant better psychomotor skills especially for those subtests where both hands had to be coordinated simultaneously.

Conclusions

The ability to partially weight bear is associated with psychomotor skills. The MLS seems to be a tool that helps predicting the ability to keep within the prescribed load limits.

In vitro assessments of reverse glenoid stability using displacement gages are misleading - recommendations for accurate measurements of interface micromotion

BACKGROUND

Baseplate micromotion of the reverse shoulder glenoid component can lead to implant loosening. We hypothesized that a remotely positioned displacement gage measures elastic deformation of the system rather than actual micromotion at the implant/bone interface.

METHODS

Reverse glenoid components were implanted into polyurethane blocks of 3 different densities. A 700 N compressive load was maintained and a vertical 700 N shear load was applied for 1000 cycles. In addition to the typical gage measurement, a digital image analysis of micromotion at the implant/block interface using high resolution cameras was performed. The measurements were validated on human specimens. A finite element model was implemented to study the isolated effect of block deformation on baseplate displacements.

FINDINGS

With the gage, typically reported micromotions were measured. Two orders of magnitude lower micromotions were detected using interface image-based analysis. The finite element simulation showed that elastic deformation alone can cause micromotion magnitudes as measured with displacement gages. Polyurethane blocks of 20 and 15 lbs per cubic foot density best reproduced micromotions as measured on human specimens.

INTERPRETATION

We found considerably less relative micromotion at the implant/bone interface than previously assumed. Gage measurements quantify elastic deformation and not true interface micromotion. High resolution digital imaging at the implant/bone interface is strongly recommended for an accurate assessment of reverse glenoid component micromotion. Tests should further adopt 20 or 15 pcf bone test surrogates. Further studies are required to identify the failure modes encountered in vivo, and a corresponding in vitro testing methodology can then be developed.

Influence of test temperature on biomechanical properties of all-inside meniscal repair devices and inside-out meniscus sutures--evaluation of an isolated distraction loading, worst-case scenario

BACKGROUND

Studies on the biomechanical properties of meniscus repairs are usually performed at room instead of body temperature. However, various all-inside meniscal repair devices include bioabsorbable materials, which are mechanically sensitive to higher environmental temperatures. Therefore, we hypothesize that current test standards may systematically lead to a false overestimation of their performance.

METHODS

In 84 cadaveric bovine lateral menisci, an artificial vertical lesion was repaired with different all-inside meniscal repair devices (FasT-Fix, FasT-Fix AB, RapidLoc, Meniscus Arrow, Meniscus Screw) compared to a vertical inside-out Ethibond Excel 2.0 suture loop. Maximum load-to-failure, stiffness, and failure mode were tested in a uniaxial distraction loading at 20°C and 37°C.

FINDINGS

Most of the tested implants were not susceptible to the higher environmental test temperature with respect to maximum load-to-failure, stiffness, and failure mode. Only the RapidLoc showed a significantly decreased stiffness (-28.1%) and a statistical trend to lower maximum load-to-failure (-20.6%) at 37°C compared to 20°C.

INTERPRETATION

20°C environmental temperature seems to be an acceptable test condition for the most meniscal repair devices. However, if the bioabsorbable part of the implant is the weakest link, body temperature may be considered for testing to prevent false overestimation of the biomechanical properties. For future biomechanical in vitro testing of meniscal repair devices, this study may provide novel insight into biomechanical test protocols for considering the environmental test temperature as an influencing factor of the biomechanical properties of especially bioabsorbable meniscal repair devices.

Tensile and shear loading stability of all-inside meniscal repairs: an in vitro biomechanical evaluation

BACKGROUND

Most biomechanical studies for evaluation of the structural properties of meniscal repairs have been performed in tensile loading scenarios perpendicular to the circumferential meniscal fibers. However, meniscal repair constructs are also exposed to shear forces parallel to the circumferential meniscal fibers during healing, particularly in the midportion of the meniscus.

HYPOTHESIS

Material properties of meniscal repair devices cannot be extrapolated from tensile to shear load scenarios.

STUDY DESIGN

Controlled laboratory study.

METHODS

In 84 harvested and isolated bovine lateral menisci following removal of adjacent soft tissue, a standardized vertical lesion was set followed by repair using all-inside flexible (FasT-Fix, FasT-Fix AB, RapidLoc) and rigid (Meniscus Screw, Meniscus Arrow) meniscal repair devices. Vertical and horizontal 2.0 Ethibond sutures were used as controls. The repaired meniscal construct was tested in a tensile (parallel to the axis of the tested repair device) and shear load scenario (perpendicular to the axis of the tested repair device) at 5 mm/min and 37 degrees C environmental temperature. Maximum load to failure, stiffness, and failure mode were recorded.

RESULTS

The absolute load to failure values of each repair device in the shear scenario were only marginally different from the tensile load scenario. However, the stiffness of several tested devices was markedly reduced in the shear scenario. In both scenarios, large differences of the load to failure and the stiffness between the implant types up to 5-fold were found (P < .05). The failure mode of several all-inside flexible repair devices was different in the shear versus tensile load scenario, while the failure mode of the rigid systems was similar in both scenarios.

CONCLUSION

All-inside meniscal repair devices exposed to shear load scenarios have comparable maximum loads to failures as tensile load scenarios. However, the stiffness of the majority of the flexible meniscal repair implants in a shear load scenario is markedly reduced. The applied scenario also affects the failure mode in several flexible meniscal repair devices.

CLINICAL RELEVANCE

Meniscal repair devices with sufficient stiffness and stability against shear loads may be favored for meniscal repair, especially within the midportion of the meniscus where shear loads occur during healing.

The effect of component positioning on intrinsic stability of the reverse shoulder arthroplasty

HYPOTHESIS

Anterior instability is one of the most common complications in reverse shoulder replacement. This study hypothesized that intrinsic stability of a reverse prosthesis varies with the degree of version of the humerus and glenoid components. This should provide guidelines on how to best position the implant components to decrease the rate of dislocation.

MATERIALS AND METHODS

Resistance to anterior dislocation of a reverse implant was measured in a mechanical testing machine by means of the stability ratio (ratio of peak dislocation/axial compressive forces). Versions of the humeral and glenoid components were modified in 10 degrees steps in the 90 degrees abducted and resting positions.

RESULTS

In both tested positions, the effect of humeral component version was highly significant. Only a glenoid component retroversion of 20 degrees led to a statistically significant drop in stability ratio for the 20 degrees abducted position. Intrinsic stability in the typical component positioning (neutral glenoid version and 20 degrees humeral retroversion) yielded comparably low intrinsic stability, which could only be improved by increasing anteversion of the humeral component.

DISCUSSION

Version of the humeral component is the critical factor for intrinsic stability. Version of the glenoid component is less important for intrinsic stability, but special care should be given to avoid retroversions of more than 10 degrees . Within this range, the surgeon can concentrate primarily on other parameters critical for long-term outcome (range of motion, secure fixation) when choosing the appropriate glenoid version.

CONCLUSION

Anterior stability can be improved by implanting the humeral component in neutral or with some anteversion.

Misalignment of total ankle components can induce high joint contact pressures

BACKGROUND

A major cause of the limited longevity of total ankle replacements is premature polyethylene component wear, which can be induced by high joint contact pressures. We implemented a computational model to parametrically explore the hypothesis that intercomponent positioning deviating from the manufacturer's recommendations can result in pressure distributions that may predispose to wear of the polyethylene insert. We also investigated the hypothesis that a modern mobile-bearing design may be able to better compensate for imposed misalignments compared with an early two-component design.

METHODS

Two finite element models of total ankle replacement prostheses were built to quantify peak and average contact pressures on the polyethylene insert surfaces. Models were validated by biomechanical testing of the two implant designs with use of pressure-sensitive film. The validated models were configured to replicate three potential misalignments with the most

CLINICAL RELEVANCE

version of the tibial component, version of the talar component, and relative component rotation of the two-component design. The misalignments were simulated with use of the computer model with physiologically relevant boundary loads.

RESULTS

With use of the manufacturer's guidelines for positioning of the two-component design, the predicted average joint contact pressures exceeded the yield stress of polyethylene (18 to 20 MPa). Pressure magnitudes increased as implant alignment was systematically deviated from this reference position. The three-component design showed lower-magnitude contact pressures in the standard position (<10 MPa) and was generally less sensitive to misalignment. Both implant systems were sensitive to version misalignment.

CONCLUSIONS

In the tested implants, a highly congruent mobile-bearing total ankle replacement design yields more evenly distributed and lower-magnitude joint contact pressures than a less congruent design. Although the mobile-bearing implant reduced susceptibility to aberrant joint contact characteristics that were induced by misalignment, predicted average contact stresses reached the yield stress of polyethylene for imposed version misalignments of >5 degrees.

Shoulder abduction moment arms in three clinically important positions

The abduction moment arms of 4 shoulder muscles were calculated in clinically important positions to evaluate the best test situation for the supraspinatus based on its mechanical advantage.Moment arms of the supraspinatus, infraspinatus, and middle and anterior deltoid in 18 individuals were computed using individual magnetic resonance imaging data and a computer-assisted design tool for simulation. Three tests with the arm in the neutral position (arm hanging on side), at 90 of scaption,and at 90 of scaption and full internal humeral rotation (Jobe test) were investigated. The supraspinatushas a greater mechanical advantage vs the other tested muscles in the neutral arm position. In the Jobe position, the supraspinatus' abduction moment arm is reduced with increased internal humeral rotation.Comparing these results with the literature indicates that this new method is adequate for calculation of moment arms and may be used in any desired joint configuration.

Numerical modelling of the shoulder for clinical applications

Research activity involving numerical models of the shoulder is dramatically increasing, driven by growing rates of injury and the need to better understand shoulder joint pathologies to develop therapeutic strategies. Based on the type of clinical question they can address, existing models can be broadly categorized into three groups: (i) rigid body models that can simulate kinematics, collisions between entities or wrapping of the muscles over the bones, and which have been used to investigate joint kinematics and ergonomics, and are often coupled with (ii) muscle force estimation techniques, consisting mainly of optimization methods and electromyography-driven models, to simulate muscular action and joint reaction forces to address issues in joint stability, muscular rehabilitation or muscle transfer, and (iii) deformable models that account for stress-strain distributions in the component structures to study articular degeneration, implant failure or muscle/tendon/bone integrity. The state of the art in numerical modelling of the shoulder is reviewed, and the advantages, limitations and potential clinical applications of these modelling approaches are critically discussed. This review concentrates primarily on muscle force estimation modelling, with emphasis on a novel muscle recruitment paradigm, compared with traditionally applied optimization methods. Finally, the necessary benchmarks for validating shoulder models, the emerging technologies that will enable further advances and the future challenges in the field are described.

Primary isolated subtalar arthrodesis: outcome after 2 to 5 years followup

BACKGROUND

Favorable to excellent clinical results have been reported for isolated subtalar joint arthrodesis. Pedobarography after subtalar bone-block distraction arthrodesis have demonstrated a more laterally shifted gait line. However pedobarographic measurements after primary in-situ isolated subtalar arthrodesis have not been reported. This is the first study considering this.

MATERIALS AND METHODS

Physical examination, AOFAS Hindfoot score, full weightbearing anterior/posterior and lateral radiographs were assessed in 15 feet. Peak pressures, ground reaction force and force distribution at foot-flat and push-off were measured.

RESULTS

Average AOFAS-Score significantly improved. Subjective satisfaction was high. Non-union was found in 1 foot (7%), screws were removed in 4 of the 15 feet (27%). One new asymptomatic arthritic talonavicular joint was found. The pressure and force distributions under the operated and contralateral foot showed a different pattern compared to a normal foot. Ground reaction force under both the operated and contralateral feet were lower than a normal foot.

DISCUSSION

This study found good clinical, subjective and radiographic results matching that of the reported literature. However, pedobarographic assessment suggests that great functional differences still remain when compared to a normal foot. Subtalar arthrodesis may induce an abnormal gait pattern by preventing compensation of axial rotation of the tibia. This is also reflected in the unaffected side, which may indicate an effort in the general locomotor control to keep a symmetrical gait pattern. This finally alters the pressure and force distribution under both feet. Nevertheless, subtalar arthrodesis is considered a valuable treatment for various isolated subtalar disorders.

Latissimus dorsi transfer to restore external rotation with reverse shoulder arthroplasty: a biomechanical study

In patients with pseudoparesis of the shoulder resulting from irreparable rotator cuff tears, reverse shoulder arthroplasty (RSA) can restore active elevation, but external rotation remains less predictable. Latissimus dorsi transfer (LDT) has been shown to be effective in restoring external rotation in patients with posterosuperior tears of the rotator cuff. The aim of this study is to determine the capacity of the LDT to restore external rotation in combination with RSA and to investigate the mechanical advantage produced by 3 different insertion sites. A biomechanical model was created using a reverse total shoulder prosthesis with 3 different transfer insertions. Moment arms were measured for 2 static positions and 1 motion of the humerus. The moment arm analysis showed that LDT can improve active external rotation in the setting of a reverse prosthesis. An insertion site on the posterior side of the greater tuberosity (adjacent to the teres minor insertion) produced a greater external rotation moment arm.

Influence of component positioning on impingement in conventional total shoulder arthroplasty

BACKGROUND

Clinical experience suggests that component impingement can lead to eccentric implant loading and thereby cause glenoid loosening in conventional total shoulder arthroplasty. This study tests the hypothesis that certain implant component positioning configurations may lead to impingement within the physiological range of motion.

METHODS

A rigid-body model of the shoulder comprising the scapula and humerus was constructed. Within this 3D model, a commercially available total shoulder arthroplasty implant was positioned according to manufacturer guidelines. The configuration was modified around this default position to investigate the associated angle of inferior and superior impingement during glenohumeral elevation, as well as in lateral impingement during axial rotation at both 0 degrees and 60 degrees of glenohumeral elevation. Glenoid component size, version, inclination and inferior-superior offset as well as humeral component size, torsion, inclination, offset and height were examined. The influence of the humeral calcar anatomy was also investigated.

FINDINGS

Certain implant configurations caused component impingement in the physiological range of motion. The most sensitive parameters affecting impingement were: (1) the inclination of the glenoid component, (2) the inferior-superior position of the humeral component along the resection line and (3) the prominence of the humeral calcar. Glenoid offset and inclination and humeral head offset and height directly affected subacromial impingement.

INTERPRETATION

This study suggests that several intraoperatively adjustable implant positioning parameters can influence the likelihood of implant impingement in conventional total shoulder arthroplasty, and that the geometry of the humeral calcar should be taken into consideration when designing an operative strategy for shoulder joint replacement.

The role of the subscapularis in preventing anterior glenohumeral subluxation in the abducted, externally rotated position of the arm

BACKGROUND

Current literature suggests that the subscapularis muscle is the main active stabilizer when the humerus is abducted and externally rotated. Conservative treatment of anterior shoulder instability therefore aims at strengthening this muscle. Empirical models, however, have questioned the role of the subscapularis muscle as it has been observed to potentially support dislocation of the subluxated humeral head.

METHODS

Ten human shoulders were loaded with an anterior dislocating force and the effect of different subscapularis tensions on humeral translation was measured with the Motion Analysis system, for the abducted and externally rotated arm and neutral positions. Also, lines of action of the subscapularis segments were measured on a 3D epoxy model.

FINDINGS

Shoulders in which the humeral head migrated antero-superiorly under an external antero-inferior load were observed to dislocate under simulated active subscapularis tension in both positions. In contrast, shoulders in which the head migrated antero-inferiorly remained stable. Twice as many specimens dislocated in the abducted - externally rotated position than in the neutral position. The change in line of action of the subscapularis may account for this change.

INTERPRETATION

Exercises alone are unlikely to be adequate for all patients with anterior instability symptoms. Passive motion pattern of the humeral head might serve as an indicator as to whether the effect of strengthening the subscapularis might stabilize a shoulder without further operation. Development of a clinical test based on these findings might differentiate the non-operative from operative candidates among patients presenting with anterior instability of the shoulder.

The contralateral foot in children with unilateral clubfoot: a study of pressures and forces involved in gait

The unaffected contralateral side of patients with unilateral clubfeet has sometimes been taken as control in foot pressure measurement studies. However, it has never been shown that the pressure pattern under the contralateral foot is similar to a normal foot. Sixteen patients with unilateral clubfoot and 110 normal subjects took part in this study. All participants were aged from 4 to 8 years. Studies comprised clinical examination and foot pressure measurements in barefoot walking. Evaluations of the measurements were completed by the calculation of forces acting under 10 anatomical foot areas normalized to ground reaction force at foot-flat and push-off. Significant differences in peak pressure were observed between the control group and the contralateral foot of patients under the heel and the metatarsals 1 to 4. Significant differences in the forces at foot-flat and push-off are seen especially in the midfoot. Both sides of the patients with unilateral clubfeet exert significantly less ground reaction force than normal subjects. Different pressure and force distributions of clubfoot children on their contralateral side compared with the normal feet of the control group may indicate differences in the general control pattern generated by the central nervous system. Differences can still be observed after normalization of the forces. We therefore conclude that when foot pressure measurements are made with clubfeet, it might be advisable to use a collective of normal feet, instead of the contralateral foot, for comparison.

Metatarsophalangeal joint arthrodesis after failed Keller-Brandes procedure

BACKGROUND

Keller-Brandes resection arthroplasty for correction of symptomatic hallux valgus deformity can obtain early good results, but late complications, such as recurrence of the deformity and instability of the first ray, have been described. Arthrodesis of the first metatarsophalangeal, (MTP) joint can be done as a salvage procedure. The aim of this prospective study was to evaluate the clinical outcome of the arthrodesis and its effect on the biomechanics of the first ray.

METHODS

Between October, 1999, and December, 2002, arthrodesis of the MTP joint was done after a failed Keller-Brandes procedure in 28 feet of 26 consecutive patients. Twenty patients (22 feet) with a minimum of 24 months followup were available for clinical and radiographic assessment. Pedobarographic measurements were obtained at latest followup in 16 patients (17 feet).

RESULTS

Sixteen feet (72%) were pain-free and six feet (28%) had mild, occasional pain. The American Orthopaedic Foot and Ankle Society (AOFAS) forefoot score increased from a preoperative 44 (range 29 to 67) points to 85 (range 73 to 90) points at longest clinical followup (average 34 months, range 23 to 48, p < 0.001). The average hallux valgus angle was corrected from 24.0 (range 7 to 47) degrees preoperatively to 16.0 (range 0 to 40) degrees postoperatively (p < 0.001). Two feet had pseudoarthroses. Biomechanically, the MTP joint arthrodesis could not fully restore the function of the hallux but produced a significant improvement, allowing a more physiologic loading pattern under the hallux and the metatarsal heads.

CONCLUSIONS

First MTP joint arthrodesis after a failed Keller-Brandes procedure is a technically safe and reliable technique. It resulted in a marked reduction of pain and gain of function that produced high patient satisfaction.

Mechanical and handling properties of braided polyblend polyethylene sutures in comparison to braided polyester and monofilament polydioxanone sutures

PURPOSE

This study was designed to comprehensively compare the mechanical properties of 4 types of braided polyblend sutures with widely used braided polyester and monofilament polydioxanone sutures.

METHODS

Polyblend polyethylene sutures (FiberWire [Arthrex, Naples, FL], Herculine [Linvatec, Largo, FL], Orthocord [DePuy Mitek, Raynham, MA], and Ultrabraid [Smith & Nephew Endoscopy, Andover, MA]), a braided polyester suture (Ethibond; Ethicon, Somerville, NJ), and an absorbable monofilament polydioxanone suture (PDS II; Ethicon), all USP No. 2, were mechanically tested. Fraying resistance was tested on eyelets of metallic and absorbable suture anchors. Cartilage abrasion caused by an intra-articularly placed suture knot was simulated by fraying on distal porcine femora.

RESULTS

All polyblend sutures were stronger than Ethibond or PDS II sutures by at least a factor of 2, with or without a knot. When knotted, Herculine (261 +/- 44 N) was strongest, followed by Ultrabraid (244 +/- 3 N). FiberWire was most resistant against fraying on metallic anchors. Orthocord was by far least abrasive with absorbable anchors. Resistance to fraying was 100- to 500-fold (absorbable anchors) and 6- to 30-fold (metallic anchor) better for all polyblend sutures than for Ethibond. All braided sutures caused a similar amount of abrasion of joint cartilage, but they caused significantly more abrasion (>20-fold) than the monofilament degradable suture.

CONCLUSIONS

The ultimate strength of polyblend suture material was 2- to 2.5-fold greater than that of polyester or polydioxanone sutures, but the resistance to fraying was up to 500-fold greater than that of polyester or polydioxanone sutures. With regard to strength, this makes polyblend sutures particularly advantageous for use with metallic edges of anchors or prostheses or with absorbable anchor eyelets.

CLINICAL RELEVANCE

With a high resistance to fraying against metallic edges or a decrease in cutting of absorbable suture eyelets being up to 500-fold greater than with polyester or polydioxanone sutures, the new polyblend sutures appear to fill a void in the armamentarium of the surgeon, provided that at least 2 throws more than with conventional sutures are used for knot tying.

Effects of glenoid component version on humeral head displacement and joint reaction forces: an experimental study

The purpose of this study was to determine whether changes in glenoid version are associated with humeral head displacement and changes in the joint reaction forces, as these might contribute to instability or loosening in total shoulder replacement. A total shoulder prosthesis was implanted in neutral version in 6 cadaveric shoulders. Glenoid version was then changed in steps of 4 degrees toward more anteversion and retroversion. An increase in anteversion resulted in anterior translation of the humeral head and in eccentric loading of the anterior part of the glenoid. Retroversion was associated with posterior displacement and posterior loading of the glenoid. A change in rotation of the humeral component did not compensate for altered version of the glenoid component. These results suggest that both instability and glenoid component loosening may be related to the version of the glenoid component. Therefore, assessment of loosening and instability justifies precise assessment of glenoid component version.

Moment arms of forearm rotators

BACKGROUND

Rotation about a longitudinal axis of the forearm has been a matter of investigation for over 100 years. However, most studies were limited to only a few muscles and to their action in specific set positions of elbow and forearm rotation. This investigation aims at determining the moment arms of muscles that contribute to pronation and supination at three different angles of elbow flexion throughout the entire range of forearm rotation.

METHODS

Muscle moment arms were derived from tendon excursions that were recorded on a full-size epoxy model of the radioulnar complex. The results were verified on a fresh cadaver specimen.

FINDINGS

Moment arms of all major supinators exhibit peak values in 40-50 degrees of pronation, for all three positions of the elbow. These peak values vary with elbow position, the biceps muscle showing the highest dependency with its greatest moment arm in 90 degrees of elbow flexion. The pronators show a maximum of moment arm about the neutral position, with little dependency on elbow flexion. Brachioradialis brings the pronated, or supinated forearm into the neutral position. The bow of the radius is in function comparable to the 'throw' of a crankshaft, forming a greater lever arm between the point of insertion of the muscles and the axis of rotation of the radius.

INTERPRETATION

The observations drawn from this study could be of eminent value in planning rotator muscle transplantation, in understanding functional disorders after injury, and in the physical treatment of forearm rotator muscle deficiency. Reconstruction of the physiological anatomical arrangement in the treatment of injuries is strongly recommended for restoration of function.

Effect of experimental suprascapular nerve block on active glenohumeral translations in vivo

Static superior shoulder instability is associated with long-standing rotator cuff tears. Factors or mechanisms which can prevent superior migration of the humeral head, and therefore allow preservation or restoration of shoulder function despite nonanatomical cuff repair, are poorly understood. The question has therefore arisen, whether centering of the humeral head was the result of active shoulder muscle function. It was the goal of this experimental investigation to (1) determine the pattern of glenohumeral translations during active shoulder abduction measured by open-magnetic resonance imaging (MRI) techniques, and to (2) determine the influence of experimental paralysis of the infra- and supraspinatus muscles on these translations. In contrast to prior experimental investigations, the humeral head remained always centered in the glenoid fossa during active abduction. No superior migration of the humeral head could be provoked with experimental paralysis of the supra- and/or infraspinatus muscles. The hypothesis that static or dynamic superior humeral head displacement is prevented by active-supra- and/or infraspinatus muscle function must therefore be rejected, for the shoulder with a structurally intact muscle-tendon-bone unit.

An algorithm for estimation of shoulder muscle forces for clinical use

BACKGROUND

The shoulder joint represents an indeterminate mechanical system, making it difficult to predict individual muscle forces required to equilibrate a given arbitrary external force. Although considerable work has been published on this matter, no model exhibits the adaptability required for the analysis involving different positions of the humerus and for any external load. An algorithm involving decision-making loops is developed to predict forces exerted by muscles that cross the shoulder joint in equilibrating a given external force acting in an arbitrary direction, with the humerus in any one of 12 selected positions.

METHODS

Muscle lever arms and directions of action collected from a full-size epoxy model of the shoulder joint are used together with the external force as input. The algorithm selects an appropriate group of muscles and step by step attributes small force increments to withstand the external moment while aiming at minimising the forces involved. Each muscle force increment is stored after every loop and eventually summed up. Stability of the glenohumeral joint is the final determining factor.

FINDINGS

Six worked-out examples show interesting features of probable muscular activity. Muscle segmentation is of paramount importance for spatial control. Although stability can be achieved by increasing the overall rotator cuff activity (co-contraction), this is rarely necessary.

INTERPRETATION

The strategy of force sharing among the muscles opens up the possibility to examine the outcome of muscle deficiencies and to investigate causes of joint instability as encountered in clinical practice. Further validation of the model is still needed, but certain clinical observations can be explained.

Uncemented short-length diaphyseal segmental replacement prosthesis fixation--finite element analysis and long-term results

INTRODUCTION

Extensively porous coated segmental replacement prostheses with intramedullary cementless fixation to bone over the whole length of stem often exhibit resorption of the surrounding bone due to stress-shielding. This makes them particularly susceptible to aseptic loosening.

STUDY

A finite element analysis of the state of loading of a short-length fixation in a new prosthetic stem design has shown a definite advantage over long-length fixation. The stress pattern within the bone surrounding the prosthesis confirmed that shortening of the ongrowth area in length increases the stress values at the resection level significantly. This stem (Endlock) has been used for diaphyseal anchorage in the treatment of tumors in combination with an artificial joint of proven design in order to reduce stress shielding.

RESULTS

No Endlock stem fractures or aseptic loosenings were observed at recent follow-up. The early clinical results comply with the theoretical assumptions.

CONCLUSIONS

A short-length fixation system based on intramedullary anchorage of segmental replacement endoprostheses would possibly support physiologic adaptive processes more than fixation over the full length of the stem.

L’information du sujet schizophrène en pratique clinique : données actuelles

Social isolation has got to be one of the greatest losses in schizophrenia. For many authors, people with schizophrenia can have no friends, no spouse, and sometimes no family. Two thirds of patients with schizophrenia return to their parents' house after discharge from a hospital for the first psychosi episode. Family members generally receive very little education as to what they can expect. They may not know the importance of medication compliance. Family members are the primary victims of violence from psychotic individuals, usually their own son or daughter, and most families cannot believe their own son or daughter would be capable of such a thing. Although families are usually the main care givers at the beginning of schizophrenia they often find their experience very frustrating for a number of reasons, and relationships suffer. Family education and support have been shown to improve outcomes considerably and family education is the second strongest factor in relapse prevention. Without education and good relapse prevention families often burst out. Most of the homeless mentally ill in downtown city cores have lost their family relationships. It is not a reflection on their families so much as the lack of adequate treatment and support. The families tried and tried and lost their ill relative. A patient writes: "My father lives just outside of Monaco. My mother developed Alzheimer's a couple of years ago or so and with a series of mild strokes died recently. I haven't seen either of them very much in the last fifteen years. I have a sister, Nicole, who also lives in Paris. I lost those relationships to some degree over the years. I am rebuilding them now. Enter the professional friend, the case manager, usually in cases where the individual is quite disabled by schizophrenia and/or at considerable risk of relapse, and usually when the individual has lost their family relationships to some degree. I had a case manager for several years and always looked forward to her visits. Case managers help negotiate compliance to medication, housing, meaningful activity, substance abuse, poverty, isolation, and everything else living in the community can throw at you. Without a spouse you tend to spend a lot of time alone. One of the main reasons Marie-Claude and I moved in with each other was that neither of us was enjoying living alone. It was very romantic at first but now we are just friends who see less and less of each other. I suspect schizophrenia interferes with the quality and depth of relationships you have with other people. Amongst the people I know, schizophrenia has meant a pretty solitary life of poverty. I have a lot of acquaintances, and colleagues, but few close friends when not at work. Over the last ten years of living with schizophrenia on medication it is celibacy that has hurt the most. It saps the life out of you, your self confidence, your self esteem. In some Scandinavian countries and Holland disabled people are allowed monthly visits by state approved sex workers. To me that is only common sense. To live without sex is unnatural and can only cause emotional suffering. We don't recognize the importance of quality sexual experience in keeping people healthy and happy in France. That doesn't mean it isn't I have a pretty high profile in my community through the meaningful activity I do. From having a half dozen names and faces to remember, I now have what seems like hundreds. I have a lot of trouble remembering people's names and faces. I am still meeting new people but I'm rarely invited to socialize with any after work. They have families, full time jobs, kids, cars, cottages, etc. My life at home is pretty solitary. It's a nuisance to travel across the city to visit people. There are few people that I share a similar background with. Since people with schizophrenia tend to have trouble learning new things, and change very little as a result, we tend to have trouble making new friends. People with schizophrenia can come alive talking about things in the past before they became ill. It's as if their life grinded to halt when they became sick. I'm stuck in the mid seventies, and that's the music I like. Everybody I know with schizophrenia is quite isolated socially and I don't really know why. That is especially true for the older people in my age group. Younger people seem to be doing much better. Many still live with their parents. Most older people live alone. There is also the odd person who recovers well, returns to a career, and marries someone without schizophrenia. In cases where marriage predates the onset of schizophrenia, the outcome is often divorce although women are more likely to stick with their husbands with schizophrenia than vice versa, especially if there are already children. I hope the next generation who appears to be less disabled survives better than people of my age with schizophrenia. The goal of community integration is one that requires: more effective treatments and/or more financial support and/or a compassionate non-discriminating community. The combination of early diagnosis and atypical medications will change the face of schizophrenia. I'm not expecting more financial support from the government, but many more people with schizophrenia will start working again instead. Their social networks will develop but social networks are probably the hardest hit in schizophrenia. It's better that you never lose your friends in the first place". This testimony shows how the information of the schizophrenic patient is necessary, and underlines the importance of the relationships between the patient and his family. Our article insists on this theme, rarely developed in the literature.

[Characteristics of patients hospitalized in a specialized hospital center after after attempted suicide]

Authors have counted, during a period of one year, the totality of patients having been admitted to the Centre Hospitalier Spécialisé de la Savoie (Chambéry) following a volunteer medicinal intoxication; 227 patients have been thus included, this type of acting out concerning third more women than men. The higher impact is found in young adults (20-40 years). Professional inactivity appears as a favoring factor, while the way of life (bachelor or in couple) does not seem to have consequence on the frequency of occurrence of the suicidal attempts. Relapses are numerous, and happen in most cases during the year. Concerning used medicines, they have been generally prescribed by a practitioner or a psychiatrist. The prominent fact is the presence of a very short period between the prescription, the deliverance of the medicine and the acting out. Plurimedicinal intoxications are increasingly frequent, with often concurrent absorption of alcohol. The diminution of the use of barbiturics in ambulatory medicine to the profit of other molecules, and especially the benzodiazepines, has reduced the frequency of their use in volunteers medicinal intoxications. Benzodiazepines are the most employed medicines in this type of acting out. This epidemiological and toxicological study confirms that used substances during volunteer medicinal intoxication are a reflection of the general medicinal consumption.

[Restraint and seclusion in psychiatry: review and prospects]

In this article, the authors reviewed the literature published since 1965 concerning restraint and seclusion. They synthesized the contents of the articles reviewed using the categories of indications and contraindications; rates of seclusion and restraint as well as demographic, clinical, and environmental factors that affect these rates; effects on patients and staff; implementation; and training. The literature on restraint and seclusion supports the following: 1) Seclusion and restraint are basically efficacious in preventing injury and reducing agitation; 2) It is nearly impossible to operate a program for severely symptomatic individuals without some form of seclusion or physical or mechanical restraint; 3) Demographic and clinical factors have limited influence on rates of restraint and seclusion; 4) Training in prediction and prevention of violence, in self-defense, and in implementation of restraint and/or seclusion is valuable in reducing rates and untoward effects; 5) Studies comparing well-defined training programs have potential usefulness.

[Apropos of using patient isolation in psychiatry: point of view of nurses]

Seclusion continues to be used in the care of acutely disturbed psychiatric patients despite often emotionally charged debate about its appropriateness within mental health services. Powerful legal and moral arguments about the use of seclusion emphasize an urgent need to critically examine its role in the care of mentally ill people. This paper examines the use of seclusion on psychiatric departments in the management of acutely disturbed patients: 36 psychiatric nurses working in 6 departments in a specialized hospital (the CHS de la Savoie, in Chambery) were interviewed in relation to their perceptions of the role of seclusion. Data were analysed using grounded theory methodology revealing the core conceptual category "controlling" and two sub-categories "watching out for" and "watching over". Seclusion was found to be used as an adjunctive treatment in the care of individuals considered to be "out of control". Clinicians expressed comfort with the use of seclusion, citing a strict protocol that provided parameters for its use. While expert therapeutic interventions were described by clinicians, they are contextualized within a framework of power and control--a framework that stands in stark contrast to contemporary philosophies of nursing care, providing impetus for a reconsideration of the use of constraining practices in the care of mentally ill people.

[Vulnerability to schizophrenia. III: Importance and limits of the Identical Pairs Continuous Performance Test]

Since several investigations have shown attentional deficits both in patients with schizophrenia and in subjects at high risk for schizophrenia, these deficits could be valuable vulnerability markers for schizophrenia. The aim of this study was to investigate wether non psychotic relatives of schizophrenic probands have deficits in sustained attention as measured by the Continuous Performance Test, Identical Pairs (CPT-IP) version. The study subjects were 25 schizophrenic probands, 50 of their first-degree relatives and 46 normal controls. For each subject, attention was assessed during 6 experimental conditions (2 standard, 2 slow, 2 easy conditions) of visual stimuli (digit-numbers and shapes). In each of the six conditions, the value of the sensitive index d' in the first-degree relative group was at an intermediate level between the patient and control groups. Moreover, in the standard shape condition, the d' value was significantly lower in the schizophrenic and in the relative groups than in the control group. This deficit was all the more interesting since it was not explained by a deficit in general intellectual abilities or by psychopathology such as anxiety or depression. Furthermore, the schizophrenic patients made more random errors in the standard and in the slow number conditions than both other groups. All groups improved their performance when the stimulus duration increased and when the processing load decreased. As a conclusion, this investigation seems: 1) to confirm the existence of an attentional deficit in the first-degree relatives of patients with schizophrenia; 2) to demonstrate the interest of the CPT-IP to detect this deficit. It must be emphasized that in order to detect the deficit, one only needs to explore the standard shape condition and that under such circumstances, the CPT-IP test has the advantage of being less time consuming than tests used in previous studies.

Examiner agreement on periodontal indices during dental surveys of elders

Indices used to evaluate periodontal health have been widely accepted in epidemiological studies, yet their reliability cannot be guaranteed. The aim of this study was to evaluate the reliability of periodontal indices applied on elders. 19 elderly subjects, 73-years-old on average, were examined at a 1st appointment by 2 independent examiners. They were re-examined 2 weeks later during a 2nd session. The examinations were performed in a dental chair with good illumination. Periodontal health was evaluated using the community periodontal index of treatment need, and tooth mobility was evaluated using 2 different indices. Inter and intra-examiner agreements were evaluated using kappa statistics. Taken as an overall measurement, the CPITN was a reliable assessment of periodontal treatment need in elders. Disagreement occurred mainly on the evaluation of bleeding and shallow pockets. The detection of fairly mobile teeth was reliable; however, the performance of the more sensitive scale was deceptive. it seems that, in the case of tooth mobility, a choice has to be made between sensitivity or reproducibility. It can be concluded that examiners should be trained carefully since the reliability of the CPITN and tooth mobility evaluation were good but close to a critical level for which an agreement is classified as poor.

Examiner agreement on caries detection and plaque accumulation during dental surveys of elders

Indices used to evaluate plaque accumulation and coronal caries have been widely accepted in epidemiological studies, yet their reliability cannot be guaranteed. The aim of this study was to evaluate the reliability of clinical criteria used in coronal and root caries diagnosis and oral hygiene evaluation as applied in elders. Nineteen elderly subjects, 73 years old on average, were examined at a first appointment by two independent examiners. They were re-examined two weeks later. Plaque accumulation was evaluated using the Plaque Index (PI) and coronal and root caries were detected according to the WHO criteria and Fejerskov et al. (1991), respectively. Recurrent caries was recorded as recommended by WHO and by probing at the interface tooth-restoration. Inter- and intra-examiner agreement was evaluated using kappa statistics. The PI score showed good reliability except for examiner b, for whom a simplification of the 4-point scale in 3-point scale improved significantly the reliability. The prevalence of coronal caries was very low and intra- and inter-examiner agreement was poor. Most of the root caries lesions were covered by plaque and the kappa values indicated only poor agreement. Recurrent caries were found with good agreement using WHO criteria but the detection with the probe was not reliable. In conclusion, it seems that examiners should be trained carefully to maximise their reliability and that plaque should be removed to obtain reliable diagnoses of caries. Retraining and calibration may be necessary for surveys continuing over a long period.