Biomechanical Analysis of Intra-articular Pressure After Coracoclavicular Reconstruction

2016 ◽  
Vol 45 (1) ◽  
pp. 150-156 ◽  
Author(s):  
Andreas Voss ◽  
Hardeep Singh ◽  
Felix Dyrna ◽  
Stefan Buchmann ◽  
Mark P. Cote ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Clinical Studies ◽  
Biomechanical Analysis ◽  
Materials Testing ◽  
Testing Time ◽  
Ac Joint ◽  
Suture Button ◽  
Lateral Clavicle ◽  
Increased Risk ◽  
Coracoclavicular Reconstruction

Background: Recent biomechanical and clinical studies have demonstrated the effectiveness of suture button and pulley-type fixations for surgical treatment of acromioclavicular instability. Concerns remain that such procedures can “overconstrain” (overreduce the lateral clavicle in relation to the acromion to a nonphysiological position) the joint. Purpose/Hypothesis: The purpose of this study was to investigate the intra-articular pressure of native and reconstructed acromioclavicular (AC) joints in relation to the configuration of the joint. Anatomic (0 mm), overconstrained (−3 mm), and underconstrained (+3 mm) AC joint reconstructions were simulated. The hypothesis was that reconstructions using suture pulley systems do not increase the intra-articular pressure of the AC joint. Study Design: Controlled laboratory study. Methods: Eleven fresh-frozen cadaveric shoulders were used in this study (mean age ± SD, 60.8 ± 6.7 years). Each specimen underwent radiographic analysis by using a Zanca view to determine the basic configuration of the AC joint. A pressure Tekscan sensor was inserted in the AC joint. A servohydraulic materials testing system was used for testing. The specimens were kept in the testing machine, and the native AC position was marked at 0 mm. This allowed moving the clavicle during the surgical procedure with reference to the native anatomic position. Intra-articular pressure in the native AC joint during cyclic loading (1000 cycles; 1 Hz) was measured. After native testing, the AC ligaments and coracoclavicular ligaments were cut and reconstructed using a cortical button technique. Anatomic, −3 mm, and +3 mm positions, relative to the acromion, were cyclically loaded, and intra-articular pressure was documented. Results: According to the AC joint classification of inclination, we identified five type 1 (46%), four type 2 (36%), one type 3 (9%), and one incongruous (9%) configurations. Changes in superior displacement across the 4 conditions were not statistically significant (0.5 ± 0.8 [native], 0.01 ± 0.00 [0 mm repair], 0.02 ± 0.02 [−3 mm repair], and 0.01 ± 0.01 [+3 mm repair]; P = .162). Before testing (time point 1), pressure in the −3 mm repair (62.9 ± 70.1) differed between the native state (11.3 ± 21.8; P = .042) and the +3 mm repair (7.1 ± 18.4; P = .023). All other changes at time points 2 (after cyclic loading unloaded) and 3 (after cyclic loading loaded) in pressure were not significant. ( P = .086 and .226, respectively). Conclusion: AC joint reconstruction (within −3 to +3 mm of reduction) with a coracoclavicular suture button device does not significantly increase the intra-articular pressure of the AC joint after cyclic loading in our experimental cadaveric setup. Clinical Relevance: Recent biomechanical and clinical studies have demonstrated the effectiveness of suture button and pulley-type fixations for coracoclavicular reconstruction of the joint. Concerns remain that such procedures would “overconstrain” the joint because of the high rigidity of these pulley systems and the preservation of the lateral clavicle. This overconstraining may potentially result in pain at the lateral end of the clavicle, osteolysis, or a later increased risk of early osteoarthritis. Therefore, our results indicate that within a range of ±3 mm to the anatomic position, overconstraining may not result in a higher intra-articular pressure.

scholarly journals Timing of Bisphosphonate Initiation After Fracture: What Does the Data Really Say?

2020 ◽  
Vol 11 ◽  
pp. 215145932098036
Author(s):  
David W. Barton ◽  
C. Taylor Smith ◽  
Amit S. Piple ◽  
Sterling A. Moskal ◽  
Jonathan J. Carmouche
Keyword(s):  
Fracture Healing ◽  
Clinical Studies ◽  
Osteoporosis Treatment ◽  
The Body ◽  
Non Union ◽  
Increased Risk ◽  
Level I ◽  
Timing Of Initiation ◽  
The Impact ◽  
Published Research

Introduction: Osteoporosis is often not clinically recognized until after a fracture occurs. Individuals who have 1 fracture are at increased risk of future fractures. Prompt initiation of osteoporosis treatment following fracture is critical to reducing the rate of future fractures. Antiresorptives are the most widely used class of medications for the prevention and treatment of osteoporosis. Many providers are hesitant to initiate antiresorptives in the acute post-fracture period. Concerns include interference with bone remodeling necessary for successful fracture healing, which would cause increased rates of non-union, malunion, and refracture. While such concerns should not extend to anabolic medications, physicians may also hesitate to initiate anabolic osteoporosis therapies due to high cost and/or lack of familiarity. This article aims to briefly review the available data and present a digestible narrative summary to familiarize practicing orthopaedic surgeons with the essential details of the published research on this topic. Results: The results of 20 clinical studies and key pre-clinical studies related to the effect of anti-resorptive medications for osteoporosis on fracture healing are summarized in the body of this narrative review. Discussion & Conclusions: While few level I studies have examined the impact of timing of initiation of osteoporosis medications in the acute post-fracture period, the few that have been published do not support these concerns. Specifically, data from level I clinical trials indicate that initiating bisphosphonates as early as 2 weeks post-fracture does not increase rates of non-union or malunion. By reviewing the available data, we hope to give clinicians the confidence to initiate osteoporosis treatment promptly post-fracture.

Correlation between methylene tetrahydrofolate reductase (MTHFR) gene rs1801133 C>T polymorphisms and risk of osteoporosis

Pteridines ◽  
2021 ◽  
Vol 32 (1) ◽  
pp. 117-125
Author(s):  
Xiao Chen ◽  
Weiran Zhang ◽  
Jingmin Huang
Keyword(s):  
Clinical Studies ◽  
Meta Analysis ◽  
Recessive Gene ◽  
Fixed Effect Model ◽  
Gene Model ◽  
Methylene Tetrahydrofolate Reductase ◽  
Effect Model ◽  
Increased Risk ◽  
Regression Test ◽  
Methylene Tetrahydrofolate

Abstract Objective To evaluate the correlation between methylene tetrahydrofolate reductase (MTHFR) gene rs1801133 C>T polymorphisms and risk of osteoporosis. Methods We searched the clinical studies related to MTHFR gene rs1801133 C>T polymorphisms and risk of osteoporosis in the electronic databases of PubMed, Web of Science, EMBASE, China National Knowledge Infrastructure (CNKI), Chinese BioMedical Literature Database (CBM) and included the suitable publications in the present meta-analysis according to the inclusion and exclusion criteria. The data of included studies were extracted and pooled by a random or fixed-effect model. The odds ratio (OR) and 95% confidence interval (95% CI) were applied to demonstrate the correlation between MTHFR gene rs1801133 C>T polymorphisms and the risk of osteoporosis. Publication bias was assessed by Begg’s funnel plot and Egger’s line regression test. Results Seven case–control clinical studies were included and a data combination was made. The data was pooled by the fixed effect model because of no obvious statistical heterogeneity. The pooled results indicated that people with the T allele had increased risk of developing osteoporosis under the homologous gene model (TT vs CC) (OR = 2.36, 95% CI: 1.81–3.08, p < 0.05), dominant gene model (TT + CT) vs CC (OR = 1.47, 95% CI: 1.21–1.77, p < 0.05) and recessive gene model TT vs (CC + CT) (OR = 2.16, 95% CI: 1.71–2.74, p < 0.05). Egger’s line regression test indicated no significant publication bias for the present meta-analysis in the above homologous, dominant, and recessive gene models. Conclusion The MTHFR gene rs1801133 C>T polymorphisms are associated with osteoporosis and subjects with the T allele have an increased risk of developing osteoporosis.

scholarly journals Dopamine D1 receptor availability is not associated with delusional ideation measures of psychosis proneness

2018 ◽  
Author(s):  
Granville James Matheson ◽  
Pontus Plavén-Sigray ◽  
Anaïs Louzolo ◽  
Jacqueline Borg ◽  
Lars Farde ◽  
...  
Keyword(s):  
Clinical Studies ◽  
Dopamine D1 Receptor ◽  
D1 Receptor ◽  
Psychotic Symptoms ◽  
Antipsychotic Treatment ◽  
Exact Nature ◽  
Healthy Controls ◽  
Psychosis Proneness ◽  
Delusional Ideation ◽  
Increased Risk

AbstractThe dopamine D1 receptor (D1R) is thought to play a role in psychosis and schizophrenia, however the exact nature of this involvement is not clear. Positron emission tomography studies comparing D1R between patients and control subjects have produced inconsistent results. An important confounding factor in most clinical studies is previous exposure to antipsychotic treatment, which is thought to influence the density of D1R. To circumvent some of the limitations of clinical studies, an alternative approach for studying the relationship between D1R and psychosis is to examine individuals at increased risk for psychotic disorders, or variation in subclinical psychotic symptoms such as delusional ideation within the general population, referred to as psychosis proneness traits. In this study, we investigated whether D1R availability is associated with delusional ideation in healthy controls using data from 76 individuals measured with PET using [11C]SCH23390 and 217 individuals who completed delusional ideation questionnaires, belonging to three different study cohorts. We first performed exploratory, hypothesis-generating, analyses by creating and evaluating a new measure of delusional ideation (n=132 and n=27), which was then found to show a negative association with D1R availability (n=24). Next, we performed confirmatory analyses using Bayesian statistical modelling, in which we first attempted to replicate this result (n=20), and then evaluated the association of Peters Delusion Inventory scores with D1R availability in two independent cohorts (n=41 and 20). Collectively, we found strong evidence that there is little to no linear association between delusional ideation and D1R availability in healthy controls. If differences in D1R can be confirmed in drug-naive schizophrenia patients compared to controls, further studies are needed to ascertain whether these changes occur at the onset of psychotic symptoms or if they are associated with specific behavioural or genetic aspects of psychosis proneness other than delusional ideation.

Transmural supraspinatus tendon tear caused by suture anchor tip 19-month postacromioclavicular joint stabilisation

2021 ◽  
Vol 14 (7) ◽  
pp. e242511
Author(s):  
Manuel Waltenspül ◽  
Karl Wieser ◽  
Samy Bouaicha
Keyword(s):  
Case Report ◽  
Rotator Cuff ◽  
Suture Anchor ◽  
Supraspinatus Tendon ◽  
Anatomical Location ◽  
Ac Joint ◽  
Tendon Tear ◽  
Paediatric Patients ◽  
Lateral Clavicle ◽  
Rotator Cuff Injuries

Rotator cuff injuries present rarely in paediatric patients due to the tendon strength at this age. There are reports of ruptures caused by either irritation of the lateral clavicle or acromioclavicular (AC) joint in fractures or after usage of hook plates. In this case report, we present a patient with an acute complete supraspinatus rupture caused by a suture anchor tip from a previously performed AC joint stabilisation. After the diagnosis of a new complete supraspinatus, the causative prominent suture anchor was removed, and the tendon subsequently repaired. This case highlights the close anatomic relation of the AC joint and the rotator cuff, which is imperative to adequately address in injuries to this anatomical location.

scholarly journals Medial migration in cephalomedullary nail fixation of pertrochanteric hip fractures

2019 ◽  
Vol 8 (7) ◽  
pp. 313-322 ◽  
Author(s):  
G. W. Law ◽  
Y. R. Wong ◽  
A. K-S. Yew ◽  
A. C. T. Choh ◽  
J. S. B. Koh ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Hip Fractures ◽  
Tensile Loading ◽  
Biomechanical Analysis ◽  
Cephalomedullary Nail ◽  
Compression Loading ◽  
Medial Migration ◽  
Group 3 ◽  
Group 2

Objectives The paradoxical migration of the femoral neck element (FNE) superomedially against gravity, with respect to the intramedullary component of the cephalomedullary device, is a poorly understood phenomenon increasingly seen in the management of pertrochanteric hip fractures with the intramedullary nail. The aim of this study was to investigate the role of bidirectional loading on the medial migration phenomenon, based on unique wear patterns seen on scanning electron microscopy of retrieved implants suggestive of FNE toggling. Methods A total of 18 synthetic femurs (Sawbones, Vashon Island, Washington) with comminuted pertrochanteric fractures were divided into three groups (n = 6 per group). Fracture fixation was performed using the Proximal Femoral Nail Antirotation (PFNA) implant (Synthes, Oberdorf, Switzerland; n = 6). Group 1 was subjected to unidirectional compression loading (600 N), with an elastomer (70A durometer) replacing loose fracture fragments to simulate surrounding soft-tissue tensioning. Group 2 was subjected to bidirectional loading (600 N compression loading, 120 N tensile loading), also with the elastomer replacing loose fracture fragments. Group 3 was subjected to bidirectional loading (600 N compression loading, 120 N tensile loading) without the elastomer. All constructs were tested at 2 Hz for 5000 cycles or until cut-out occurred. The medial migration distance (MMD) was recorded at the end of the testing cycles. Results The MMDs for Groups 1, 2, and 3 were 1.02 mm, 6.27 mm, and 5.44 mm respectively, with reliable reproduction of medial migration seen in all groups. Bidirectional loading groups showed significantly higher MMDs compared with the unidirectional loading group (p < 0.01). Conclusion Our results demonstrate significant contributions of bidirectional cyclic loading to the medial migration phenomenon in cephalomedullary nail fixation of pertrochanteric hip fractures. Cite this article: G. W. Law, Y. R. Wong, A. K-S. Yew, A. C. T. Choh, J. S. B. Koh, T. S. Howe. Medial migration in cephalomedullary nail fixation of pertrochanteric hip fractures: A biomechanical analysis using a novel bidirectional cyclic loading model. Bone Joint Res 2019;8:313–322. DOI: 10.1302/2046-3758.87.BJR-2018-0271.R1.

The Integrity of the Acromioclavicular Capsule Ensures Physiological Centering of the Acromioclavicular Joint Under Rotational Loading

2018 ◽  
Vol 46 (6) ◽  
pp. 1432-1440 ◽  
Author(s):  
Felix G.E. Dyrna ◽  
Florian B. Imhoff ◽  
Andreas Voss ◽  
Sepp Braun ◽  
Elifho Obopilwe ◽  
...  
Keyword(s):  
Translational Motion ◽  
Measuring System ◽  
Resistance Force ◽  
Materials Testing ◽  
Detailed Knowledge ◽  
Native State ◽  
Ac Joint ◽  
Axial Forces ◽  
Resistance Torque ◽  
Posterior Translation

Background: The acromioclavicular (AC) capsule is an important stabilizer against horizontal translation and also contributes to the strut function of the clavicle, which guides rotation of the scapula. To best reproduce the biomechanical properties and the complex 3-dimensional (3D) guidance of the AC joint, detailed knowledge of the contribution of each of the distinctive capsular structures is needed. Purpose/Hypothesis: To perform a detailed biomechanical evaluation of the specific capsular structures of the AC joint and their contribution to translational and rotational stability. The hypothesis was that successive cutting of each quadrant of the AC capsule would result in increased instability and increased amplitude of the clavicle’s motion in relation to the acromion. Study Design: Controlled laboratory study. Methods: Thirty-two fresh-frozen human cadaveric shoulders were used. Each scapula was fixed to a swivel fixture of a servohydraulic materials testing system. The AC capsule was dissected in serial steps with immediate rotational and horizontal testing after each cut. A 3D optical measuring system was used to evaluate 3D movement. Posterior translation, rotation, and displacement of the lateral clavicle in relation to the center of rotation were measured. Torques and axial forces required to rotate and translate the clavicle were recorded. Results: When posterior translational force was applied, all specimens with a completely cut AC capsule demonstrated a significant loss of resistance force against the translational motion when compared with the native state ( P < .05). The resistance force against posterior translation was reduced to less than 27% of the native state for all specimens. Sequential cutting of the AC capsule resulted in a significant reduction of resistance torque against anterior rotation for all specimens with less than 22% of resistance force compared with the native state. Cutting 50% of the capsule reduced the resistance torque for all segments and all testing modalities (posterior translation as well as anterior and posterior rotation) significantly compared with the native state ( P < .05). Cutting the entire AC capsule resulted in a significant increase in motion within the joint as a sign of decentering of the AC joint when torque was applied. All groups demonstrated a significant increase of motion in all directions when the AC capsule was cut by 50%. Conclusion: Cutting the entire capsule (with intact coracoclavicular [CC] ligaments) reduced the resistance force to less than 25% compared with the native state during translational testing and less than 10% compared with the native state during rotational testing. However, the anterior segments of the capsule provided the greatest stability under rotational loading. Second, the amplitude of the joint’s motion significantly increased under rotational stress, indicating increased amplitude of the clavicle’s motion in relation to the acromion when the ligamentous structures of the AC capsule are dissected. Clinical Relevance: To best restore stability to the AC joint, the relevance and function of each section of the circumferential AC capsule need to be understood. Our findings support the synergistic contribution of the CC ligaments and AC capsular structures to AC joint stability. This synergy supports the need to address both structures to achieve anatomic reconstruction.

Posterior Rotational and Translational Stability in Acromioclavicular Ligament Complex Reconstruction: A Comparative Biomechanical Analysis in Cadaveric Specimens

2020 ◽  
Vol 48 (10) ◽  
pp. 2525-2533
Author(s):  
Daichi Morikawa ◽  
Joel B. Huleatt ◽  
Lukas N. Muench ◽  
Cameron Kia ◽  
Daniel P. Berthold ◽  
...  
Keyword(s):  
Surgical Techniques ◽  
Biomechanical Analysis ◽  
Rotational Stability ◽  
Posterior Instability ◽  
Ligament Repair ◽  
Ac Joint ◽  
Improved Stability ◽  
Horizontal Stability ◽  
Posterior Translation ◽  
Joint Biomechanics

Background: Persistent posterior instability of the acromioclavicular (AC) joint is a reported complication after isolated coracoclavicular (CC) reconstruction. Thus, multiple techniques have been proposed attempting to restore biomechanics of the AC ligament complex (ACLC). Purpose/Hypothesis: The purpose was to evaluate the posterior translational and rotational stability of an ACLC reconstruction with a dermal allograft (ACLC patch) as compared with 3 suture brace constructs. It was hypothesized that the ACLC patch would better restore AC joint posterior stability. Study Design: Controlled laboratory study. Methods: A total of 28 cadaveric shoulders (mean ± SD age, 57.6 ± 8.3 years) were randomly assigned to 1 of 4 surgical techniques: ACLC patch, oblique brace, anterior brace, and x-frame brace. The force and torque to achieve 10 mm of posterior translation and 20° of posterior rotation of the AC joint were recorded in the following conditions: intact, transected ACLC, ACLC patch/brace repair, ACLC patch/brace repair with dissected CC ligaments, and ACLC patch/brace repair with CC ligament repair. Results: For posterior translation, transection of the ACLC reduced resistance to 16.7% of the native. With the native CC ligaments intact, the ACLC patch (59.1%), oblique brace (54.1%), and anterior brace (60.7%) provided significantly greater stability than the x-frame brace (33.2%; P < .001, P = .008, P < .001, respectively). ACLC patch, oblique brace, and anterior brace continued to have significantly higher posterior translational resistance than the x-frame (35.1%; P < .001, P = .003, P < .001) after transection and subsequent CC ligament repair. For posterior rotation, transection of the ACLC decreased the resistance to 5.4% of the intact state. With the CC ligaments intact, the ACLC patch (77.1%) better restored posterior rotational stability than the oblique (35.3%), anterior (48.5%), and x-frame (23.0%) brace repairs ( P < .001, P = .002, P < .001). CC ligament transection and subsequent repair demonstrated the ACLC patch (41.0%) to have improved stability when compared with the oblique (16.0%), anterior (14.0%), and x-frame (12.7%) repairs ( P = .006, P = .003, P = .002). Conclusion: ACLC reconstruction with a dermal allograft better restored native posterior rotational stability than other brace constructs, with translational stability similar to the oblique and anterior brace technique at the time of surgery. Clinical Relevance: Horizontal stability of the AC joint is primarily controlled by the ACLC. Inability to restore AC joint biomechanics can result in persistent posterior instability and lead to functional impairment.

Therapeutic and preventive properties of honey and its bioactive compounds in cancer: an evidence-based review

2019 ◽  
Vol 33 (1) ◽  
pp. 50-76 ◽  
Author(s):  
Sadia Afrin ◽  
Shoja M. Haneefa ◽  
Maria J. Fernandez-Cabezudo ◽  
Francesca Giampieri ◽  
Basel K. al-Ramadi ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Bioactive Compounds ◽  
Clinical Studies ◽  
Natural Antioxidants ◽  
Cancer Models ◽  
Increased Risk ◽  
Anti Cancer ◽  
Preclinical Animal Models

AbstractDespite the much improved therapeutic approaches for cancer treatment that have been developed over the past 50 years, cancer remains a major cause of mortality globally. Considerable epidemiological and experimental evidence has demonstrated an association between ingestion of food and nutrients with either an increased risk for cancer or its prevention. There is rising interest in exploring agents derived from natural products for chemoprevention or for therapeutic purposes. Honey is rich in nutritional and non-nutritional bioactive compounds, as well as in natural antioxidants, and its potential beneficial function in human health is becoming more evident. A large number of studies have addressed the anti-cancer effects of different types of honey and their phenolic compounds using in vitro and in vivo cancer models. The reported findings affirm that honey is an agent able to modulate oxidative stress and has anti-proliferative, pro-apoptotic, anti-inflammatory, immune-modulatory and anti-metastatic properties. However, despite its reported anti-cancer activities, very few clinical studies have been undertaken. In the present review, we summarise the findings from different experimental approaches, including in vitro cell cultures, preclinical animal models and clinical studies, and provide an overview of the bioactive profile and bioavailability of the most commonly studied honey types, with special emphasis on the chemopreventive and therapeutic properties of honey and its major phenolic compounds in cancer. The implications of these findings as well as the future prospects of utilising honey to fight cancer will be discussed.

Cyclic Testing of Flexible All-Inside Meniscus Suture Anchors: Biomechanical Analysis

2005 ◽  
Vol 33 (3) ◽  
pp. 388-394 ◽  
Author(s):  
Thore Zantop ◽  
Ann K. Eggers ◽  
Volker Musahl ◽  
Andre Weimann ◽  
Wolf Petersen
Keyword(s):  
Cyclic Loading ◽  
Biomechanical Properties ◽  
Meniscus Repair ◽  
Biomechanical Analysis ◽  
Suture Techniques ◽  
Suture Anchors ◽  
Pull Out ◽  
Meniscus Suture ◽  
Significant Difference ◽  
Pull Out Strength

Background Flexible meniscus repair devices are designed to combine the benefits of rigid all-inside meniscus anchors with the biomechanical properties of sutures. Hypothesis Stiffness and pull-out strength of flexible all-inside suture anchors and conventional sutures under cyclic loading conditions will be comparable. Study Design Controlled laboratory study Methods In 50 fresh frozen bovine menisci, artificial meniscus lesions were repaired with different meniscus fixation techniques: horizontal and vertical FasT-Fix, RapidLoc, and horizontal and vertical 2-0 Ethibond sutures. The specimens were cycled 1000 times between 5 and 20 N and then loaded to failure. Results All devices survived the cyclic loading protocol. There was no significant difference in the displacement between all repair techniques tested (horizontal FasT-Fix, 6.23 mm; vertical FasT-Fix, 5.34 mm; RapidLoc, 6.84 mm; horizontal 2-0 Ethibond, 6.03 mm; vertical 2-0 Ethibond, 5.61 mm (P >. 05). Vertical and horizontal FasT-Fix suture anchors had a significantly higher stiffness and pull-out strength (94.1 N and 80.8 N, respectively) than did horizontal sutures (50.2 N) and RapidLoc devices (30.3 N) (P >. 05). Conclusions In this study, flexible all-inside meniscus anchors (FasT-Fix) had higher pull-out strength than did conventional vertical suture techniques. Biomechanical characteristics of the flexible RapidLoc are comparable to those of horizontal sutures. Clinical Relevance Flexible all-inside meniscus repair devices are an alternative to conventional suture techniques.

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