The impact of heating, ventilation, and air conditioning design features on the transmission of viruses, including the 2019 novel coronavirus: A systematic review of filtration.

Historically, viruses have demonstrated airborne transmission. Emerging evidence suggests the novel coronavirus (SARS-CoV-2) that causes COVID-19 also spreads by airborne transmission. This is more likely in indoor environments, particularly with poor ventilation. In the context of airborne transmission, a vital mitigation strategy for the built environment is heating, ventilation, and air conditioning (HVAC) systems. HVAC features could modify virus transmission potential. A systematic review was conducted to identify and synthesize research examining the effectiveness of filters within HVAC systems in reducing virus transmission. A comprehensive search of OVID MEDLINE, Compendex, and Web of Science Core was conducted to January 2021. Two authors were involved in study selection, data extraction, and risk of bias assessments. Study characteristics and results were displayed in evidence tables and findings were synthesized narratively. Twenty-three relevant studies showed that: filtration was associated with decreased transmission; filters removed viruses from the air; increasing filter efficiency (efficiency of particle removal) was associated with decreased transmission, decreased infection risk, and increased viral filtration efficiency (efficiency of virus removal); increasing filter efficiency above MERV 13 was associated with limited benefit in further reduction of virus concentration and infection risk; and filters with the same efficiency rating from different companies showed variable performance. Adapting HVAC systems to mitigate virus transmission requires a multi-factorial approach and filtration is one factor offering demonstrated potential for decreased transmission. For filtration to be effective, proper installation is required. Of note, similarly rated filters from different companies may offer different virus reduction results. While increasing filtration efficiency (i.e., increasing MERV rating or moving from MERV to HEPA) is associated with virus mitigation, there are diminishing returns for filters rated MERV 13 or higher. Although costs increase with filtration efficiency, they are lower than the cost of ventilation options with the equivalent reduction in transmission. Systematic review registration: PROSPERO 2020 CRD42020193968.

Compressive mechanical properties of vitrified porcine menisci are superior to frozen and similar to fresh porcine menisci.

The common practice of freezing meniscal allograft tissue is limited due to the formation of damaging ice crystals. Vitrification, which eliminates the formation of damaging ice crystals, may allow the mechanical properties of meniscal allograft tissue to be maintained during storage and long-term preservation. The primary objective of this study was to investigate the differences between fresh, frozen, and vitrified porcine lateral menisci examining compressive mechanical properties in the axial direction. Unconfined compressive stress-relaxation testing was conducted to quantify the mechanical properties of fresh, frozen and vitrified porcine lateral menisci. The compressive mechanical properties investigated were peak and equilibrium stress, secant, instantaneous and equilibrium modulus, percent stress-relaxation, and relaxation time constants from three-term Prony series. Frozen menisci exhibited inferior compressive mechanical properties in comparison with fresh menisci (significant differences in peak and equilibrium stress, and secant, instantaneous and equilibrium modulus) and vitrified menisci (significant differences in peak stress, and secant and instantaneous modulus). Interestingly, fresh and vitrified menisci exhibited comparable compressive mechanical properties (stress, modulus and relaxation parameters). These findings are significant because (1) vitrification was successful in maintaining mechanical properties at values similar to fresh menisci, (2) compressive mechanical properties of fresh menisci were characterized providing a baseline for future research, and (3) freezing affected mechanical properties confirming that freezing should be used with caution in future investigations of meniscal mechanical properties. Vitrification was superior to freezing for preserving compressive mechanical properties of menisci which is an important advance for vitrification as a preservation option for meniscal allograft transplantation.

The Impact of Heating, Ventilation, and Air-Conditioning Design Features on the Transmission of Viruses, Including SARS-CoV-2: Overview of Reviews.

BACKGROUND: The COVID-19 or SARS-CoV-2 outbreak was declared a pandemic by the World Health Organization in March 2020. Almost 2 years later (early February 2022), the World Health Organization reported over 383 million cases of the disease caused by the virus, with over 5.6 million deaths worldwide. Debate regarding the routes of transmission was substantial early in the pandemic; however, airborne transmission emerged as an important consideration. Infectious airborne agents can spread within the built environment through heating, ventilation, and air-conditioning (HVAC) systems. Multiple features of HVAC systems can influence transmission (eg, ventilation, filtration, UV radiation, and humidity). Understanding how HVAC features influence airborne transmission is critical to mitigate the spread of infectious agents. OBJECTIVE: Given the airborne transmission of SARS-CoV-2, an overview of reviews was conducted to understand what is already known from the scientific literature about how virus transmission may be affected by HVAC design features in the built environment. METHODS: Ovid MEDLINE and Compendex were searched from inception to January 2021. Two reviewers independently screened the titles, abstracts, and full text of potentially relevant reviews, using a priori inclusion criteria: systematic reviews examining the effects of HVAC design features on virus transmission. Two reviewers independently assessed the methodological quality using AMSTAR2. RESULTS: Searching identified 361 citations, of which 45 (12.5%) were potentially relevant and 7 (2%) were included. Reviews were published between 2007 and 2021 and included 47 virus studies. Two earlier reviews (2007 and 2016) of 21 studies found sufficient evidence that mechanical ventilation (airflow patterns and ventilation rates) plays a role in airborne transmission; however, both found insufficient evidence to quantify the minimum mechanical ventilation requirements. One review (2017) of 9 studies examining humidity and indoor air quality found that influenza virus survival was lowest between 40% and 80% relative humidity; the authors noted that ventilation rates were a confounding variable. Two reviews (2021) examined mitigation strategies for coronavirus transmission, finding that transmission decreased with increasing temperature and relative humidity. One review (2020) identified 14 studies examining coronavirus transmission in air-conditioning systems, finding that HVAC systems played a role in virus spread during previous coronavirus outbreaks. One review (2020) examined virus transmission interventions in public ground transportation, finding ventilation and filtration to be effective. CONCLUSIONS: Seven reviews synthesizing 47 studies demonstrated a role for HVAC in mitigating airborne virus transmission. Ventilation, humidity, temperature, and filtration can play a role in the viability and transmission of viruses, including coronaviruses. Recommendations for minimum standards were not possible owing to few studies investigating a given HVAC parameter. This overview examining HVAC design features and their effects on the airborne transmission of viruses serves as a starting point for future systematic reviews and identifying priorities for primary research.

The impact of heating, ventilation and air conditioning (HVAC) design features on the transmission of viruses, including the 2019 novel coronavirus (COVID-19): A systematic review of humidity.

The aerosol route has been a pathway for transmission of many viruses. Similarly, recent evidence has determined aerosol transmission for SARS-CoV-2 to be significant. Consequently, public health officials and professionals have sought data regarding the role of Heating, Ventilation, and Air Conditioning (HVAC) features as a means to mitigate transmission of viruses, particularly coronaviruses. Using international standards, a systematic review was conducted to comprehensively identify and synthesize research examining the effect of humidity on transmission of coronaviruses and influenza. The results from 24 relevant studies showed that: increasing from mid (40-60%) to high (>60%) relative humidity (RH) for SARS-CoV-2 was associated with decreased virus survival; although SARS-CoV-2 results appear consistent, coronaviruses do not all behave the same; increasing from low (<40%) to mid RH for influenza was associated with decreased persistence, infectivity, viability, and survival, however effects of increased humidity from mid to high for influenza were not consistent; and medium, temperature, and exposure time were associated with inconsistency in results for both coronaviruses and influenza. Adapting humidity to mitigate virus transmission is complex. When controlling humidity as an HVAC feature, practitioners should take into account virus type and temperature. Future research should also consider the impact of exposure time, temperature, and medium when designing experiments, while also working towards more standardized testing procedures. Clinical trial registration: PROSPERO 2020 CRD42020193968.

Tensile mechanical properties of vitrified porcine menisci are superior to frozen and similar to fresh porcine menisci.

Vitrification inhibits crystallization of ice and may allow the mechanical properties of menisci to be preserved for transplantation without the damaging consequences of ice crystals formed during freezing. The primary objective of this study was to investigate the differences between fresh, frozen, and vitrified porcine lateral menisci examining tensile mechanical properties along the circumferential-peripheral, circumferential-central, longitudinal, and radial orientations. The secondary objective was to investigate the variations in the tensile mechanical properties of menisci comparing the circumferential-peripheral orientation to the three other orientations: circumferential-central, longitudinal, and radial. Quasi-static tensile testing was conducted to quantify the tensile mechanical properties of fresh, frozen and vitrified menisci. Ultimate tensile strength of frozen menisci were significantly decreased compared with fresh and vitrified menisci along three orientations: circumferential-peripheral, longitudinal, and radial. Along the circumferential-central orientation, tensile modulus of frozen menisci was significantly decreased compared with fresh menisci. The mechanical properties of vitrified menisci were comparable to fresh menisci along all four orientations. For all menisci (fresh, frozen and vitrified), ultimate tensile strength and failure strain along the circumferential-peripheral orientation were significantly increased compared with the three other orientations. Freezing was detrimental to the mechanical properties of menisci but vitrification likely avoided the negative effects of freezing thereby preserving mechanical properties that were comparable to fresh menisci. The findings of this study revealed that vitrification was superior to freezing for preserving mechanical properties of meniscal tissue; hence, vitrification is likely to be a competitive alternative to freezing for meniscal transplantation in the future.

The impact of heating, ventilation, and air conditioning design features on the transmission of viruses, including the 2019 novel coronavirus: A systematic review of ultraviolet radiation.

Respiratory viruses are capable of transmitting via an aerosol route. Emerging evidence suggests that SARS-CoV-2 which causes COVID-19 can be spread through airborne transmission, particularly in indoor environments with poor ventilation. Heating, ventilation, and air conditioning (HVAC) systems can play a role in mitigating airborne virus transmission. Ultraviolet germicidal irradiation (UVGI), a feature that can be incorporated into HVAC systems, can be used to impede the ability of viruses to replicate and infect a host. We conducted a systematic review of the scientific literature examining the effectiveness of HVAC design features in reducing virus transmission-here we report results for ultraviolet (UV) radiation. We followed international standards for conducting systematic reviews and developed an a priori protocol. We conducted a comprehensive search to January 2021 of published and grey literature using Ovid MEDLINE, Compendex, and Web of Science Core. Two reviewers were involved in study selection, data extraction, and risk of bias assessments. We presented study characteristics and results in evidence tables, and synthesized results across studies narratively. We identified 32 relevant studies published between 1936 and 2020. Research demonstrates that: viruses and bacteriophages are inactivated by UV radiation; increasing UV dose is associated with decreasing survival fraction of viruses and bacteriophages; increasing relative humidity is associated with decreasing susceptibility to UV radiation; UV dose and corresponding survival fraction are affected by airflow pattern, air changes per hour, and UV device location; and UV radiation is associated with decreased transmission in both animal and human studies. While UV radiation has been shown to be effective in inactivating viruses and reducing disease transmission, practical implementation of UVGI in HVAC systems needs to consider airflow patterns, air changes per hour, and UV device location. The majority of the scientific literature is comprised of experimental, laboratory-based studies. Further, a variety of viruses have been examined; however, there are few studies of coronaviruses and none to date of SARS-CoV-2. Future field studies of UVGI systems could address an existing research gap and provide important information on system performance in real-world situations, particularly in the context of the current COVID-19 pandemic. This comprehensive synthesis of the scientific evidence examining the impact of UV radiation on virus transmission can be used to guide implementation of systems to mitigate airborne spread and identify priorities for future research. Trial registration PROSPERO 2020 CRD42020193968.

The impact of heating, ventilation, and air conditioning design features on the transmission of viruses, including the 2019 novel coronavirus: A systematic review of ventilation and coronavirus.

Aerosol transmission has been a pathway for the spread of many viruses. Similarly, emerging evidence has determined aerosol transmission for Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) and the resulting COVID-19 pandemic to be significant. As such, data regarding the effect of Heating, Ventilation, and Air Conditioning (HVAC) features to control and mitigate virus transmission is essential. A systematic review was conducted to identify and comprehensively synthesize research examining the effectiveness of ventilation for mitigating transmission of coronaviruses. A comprehensive search was conducted in Ovid MEDLINE, Compendex, Web of Science Core to January 2021. Study selection, data extraction, and risk of bias assessments were performed by two authors. Evidence tables were developed and results were described narratively. Results from 32 relevant studies showed that: increased ventilation rate was associated with decreased transmission, transmission probability/risk, infection probability/risk, droplet persistence, virus concentration, and increased virus removal and virus particle removal efficiency; increased ventilation rate decreased risk at longer exposure times; some ventilation was better than no ventilation; airflow patterns affected transmission; ventilation feature (e.g., supply/exhaust, fans) placement influenced particle distribution. Few studies provided specific quantitative ventilation parameters suggesting a significant gap in current research. Adapting HVAC ventilation systems to mitigate virus transmission is not a one-solution-fits-all approach. Changing ventilation rate or using mixing ventilation is not always the only way to mitigate and control viruses. Practitioners need to consider occupancy, ventilation feature (supply/exhaust and fans) placement, and exposure time in conjunction with both ventilation rates and airflow patterns. Some recommendations based on quantitative data were made for specific scenarios (e.g., using air change rate of 9 h-1 for a hospital ward). Other recommendations included using or increasing ventilation, introducing fresh air, using maximum supply rates, avoiding poorly ventilated spaces, assessing fan placement and potentially increasing ventilation locations, and employing ventilation testing and air balancing checks. Trial registration: PROSPERO 2020 CRD42020193968.

Challenges with organization, discoverability and access in Canadian open health data repositories.

Introduction: Open health data provides healthcare professionals, biomedical researchers and the general public with access to health data which has the potential to improve healthcare delivery and policy. The challenge is to create and implement appropriate metadata, or structured data about the data, to ensure that data are easy to discover, access and re-use. The goal of this study is to identify, evaluate and compare Canadian open health data repositories for their searching, browsing and navigation functionalities, the richness of their metadata description practices, and their metadata-based filtering mechanisms. Methods: Metadata-based search and browsing was evaluated in addition to the number and nature of metadata elements. Six Canadian open health data repositories across national, provincial and institutional levels were evaluated. Data collected using verbatim text recording was evaluated using an analytical framework based on the 2019 Dataverse North Metadata Best Practices guide and 2019 Data Citation Implementation Project roadmap. Results: All repositories required filtering to access "open health data." All repositories included 'subject' facets for filtering, and 'title' and 'description' on the Results List. Use case evaluations suggest improvements including advanced search, health-specific search terms, records for all repositories, and links to related publications. Discussion: Consistent use of 'title' and 'description' suggests that an interoperable interface is possible. Inconsistencies in records indicate the need for explicit, easy to find mechanisms to access metadata in repositories. The analytical framework represents first draft guidelines for metadata creation and implementation to improve organization, discoverability, and access to Canadian open health data.

Long-term outcomes following isolated arthroscopic Bankart repair: a 9- to 12-year follow-up.

BACKGROUND: The long-term outcomes following arthroscopic Bankart repair have been rarely reported. Because of its relative novelty, little is known about recurrent instability, postoperative arthritis, and patient satisfaction, particularly for well-established modern procedures. The purpose of the study was to evaluate the long-term outcomes following arthroscopic Bankart repair. METHODS: Patients who underwent isolated arthroscopic Bankart repair from 2003 to 2006 were retrospectively reviewed. Recurrent instability, radiographic, and clinical scores (American Shoulder and Elbow Surgeons [ASES], Simple Shoulder Test [SST], and Rowe scores) were evaluated. Patient factors (ie, age, gender, side, number of instability episodes, contact sports, and bone loss) were analyzed to determine the correlation with outcome measures. RESULTS: Among the 98 patients (102 shoulders), we were able to contact 50 patients (51 shoulders, mean age 27.0 years, mean follow-up 121.2 months). Significant bone loss in glenoid and humerus was arthroscopically observed in 16 (31.4%) and 28 (54.9%) shoulders, respectively. Sixteen shoulders (31.4%) experienced recurrent instability. Recent radiographs were obtained for 38 shoulders, 14 (36.8%) of which showed moderate to severe arthritis. Clinical outcomes at follow-up were 89.3, 10.8, and 76.0 for ASES, SST, and Rowe scores, respectively. Neither recurrent instability nor arthritis was correlated with any patient factors. CONCLUSION: When isolated arthroscopic Bankart repair was used in all patients with shoulder instability regardless of bony defect, postoperative recurrent instability and arthritis rates were unacceptably high. Additional procedures should be chosen after careful consideration of multiple patient factors.

Full-Thickness Rotator Cuff Tears: What Is the Rate of Tear Progression? A Systematic Review.

PURPOSE: To systematically review the literature and determine the rate of radiographic tear progression of nonoperatively treated full-thickness rotator cuff tears. METHODS: The PubMed, Embase, and Cochrane Library databases were systematically reviewed to identify all articles related to nonoperatively treated rotator cuff tears. English-language studies of Level I through IV evidence examining chronic, full-thickness rotator cuff tears in adults were included. Partial-thickness tears were excluded. Rotator cuff tears were analyzed according to the presence or absence of symptoms. The primary outcome was radiographic tear progression defined as an increase in tear size of 5 mm or greater on magnetic resonance imaging or ultrasound. RESULTS: Eight studies were included for statistical analysis, and 411 tears were analyzed for progression. No difference in the rate of tear progression was detected between the asymptomatic and symptomatic groups (40.6% at 46.8 months and 34.1% at 37.8 months, respectively; P = .65). Calculation of the number needed to treat showed that for an 8% retear rate at 2-year follow-up, approximately 7 patients with rotator cuff tears would have to undergo operative repair to prevent 1 tear from progressing radiographically. CONCLUSIONS: This study showed that with the data available, asymptomatic and symptomatic rotator cuff tears carry similar rates of tear progression over time. Most of these tears will not progress significantly over short- to intermediate-term follow-up. LEVEL OF EVIDENCE: Level IV, systematic review of Level I through IV evidence.

Partial-thickness rotator cuff tears: clinical and imaging outcomes and prognostic factors of successful nonoperative treatment.

PURPOSE: The purpose of this study was to determine the clinical success rate of nonoperative treatment of partial-thickness rotator cuff tears (PT-RCTs), to determine baseline clinical factors predictive of outcome of nonoperative treatment of PT-RCTs, and to determine the imaging outcome of nonoperative treatment of PT-RCTs. PATIENTS AND METHODS: All patients with a primary diagnosis of a PT-RCT were eligible for inclusion. Seventy-six patients (48 males, 28 females) with an average age of 52±10 years were included in the study. Patients were evaluated using a standardized format including clinical, imaging, and shoulder specific quality-of-life outcomes. Patients were assessed and treated either successfully nonoperatively or consented to undergo surgical intervention of their PT-RCT. Patients treated nonoperatively underwent follow-up by MRI arthrogram. RESULTS: Thirty-seven patients (49%) underwent nonoperative treatment. Logistic regression analysis indicated that the baseline variables of side (dominant or nondominant side involved), onset (traumatic or atraumatic), and thickness of tendon tear (<50% or >50%) were significant predictors of outcome. At a mean 46±7 months of follow-up, nonoperatively treated patients demonstrated a mean American Shoulder and Elbow Surgeons score of 85.1±16.0, and a Simple Shoulder Test score of 10.0±2.5. Overall, 76% of tears treated nonoperatively did not show a tear progression on anatomic imaging. Nine patients (24%) demonstrated tear progression, of which three patients (8%) demonstrated full-thickness tearing. CONCLUSION: Nonoperative treatment was utilized in ~50% of the patients and resulted in improved clinical outcomes. Onset, shoulder involved, and thickness of the tear were predictive of the success of nonoperative treatment.

Are re-injured ligaments equivalent mechanically to injured ligaments: The role of re-injury severity?

The consequences of ligament re-injury have received limited attention. Although the mechanical properties of injured ligaments improve over time, these properties are never fully recaptured, rendering these injured ligaments susceptible to re-injury. Previous injury is a significant risk factor for recurrent injury, and this re-injury can result in longer absence from activity than the initial injury. A rabbit medial collateral ligament model was used to compare mechanically re-injured right medial collateral ligaments to injured left medial collateral ligaments. Two groups of different re-injury severity were investigated: 'minor' re-injury comparing transection re-injured right medial collateral ligaments to transection injured left medial collateral ligaments; 'major' re-injury comparing gap re-injured right medial collateral ligaments to transection injured left medial collateral ligaments. Initial injuries for both groups were right medial collateral ligament transections 1 week before re-injury. After 5-6 weeks of healing, mechanical testing was performed to determine (dimensionally) cross-sectional area; (structurally) medial collateral ligament laxity, failure load, and stiffness; and (materially) cyclic creep strain and failure stress. Because we wanted to evaluate whether the mechanical properties of re-injured ligaments were equivalent or, at least, no worse than injured ligaments, we used equivalence/noninferiority testing. This approach evaluates a research hypothesis of equivalence, rather than difference, and determines whether comparisons are 'statistically equivalent', 'noninferior', or 'potentially inferior'. Transection re-injured and gap re-injured ligaments were 'statistically equivalent' structurally to transection injured ligaments. Transection re-injured ligaments were 'noninferior' both materially and dimensionally to transection injured ligaments. Gap re-injured ligaments were 'potentially inferior' both materially and dimensionally to transection injured ligaments. Two differences between the re-injuries, which affect healing, may explain the mechanical outcomes: the presence or lack of healing products and the proximity of ligament ends at the time of re-injury. Our findings suggest that (in the short term) there is a severity of re-injury below which there is no additional disadvantage to the healing process, mechanical behaviour, and resulting potential for re-injury.

Mechanical and imaging evaluation of the effect of sutures on tendons: tape sutures are protective to suture pulling through tendon.

BACKGROUND: High-strength sutures, including #2 and tape-type, are popular when performing arthroscopic rotator cuff repair. Although the most common mechanism of anatomic failure of rotator cuff repair is suture pulling through tendon, the effect of sutures on the suture-tendon interface has rarely been investigated. We evaluated the effect of commercially available modern high-strength standard #2 and tape-type sutures on tendon. METHODS: Isolated sutures (FiberTape, #2 FiberWire [Arthrex Inc., Naples, FL, USA], Ultratape, and #2 Ultrabraid [Smith & Nephew, Andover, MA, USA]) and suture-tendon constructs using sheep infraspinatus tendons were evaluated using mechanical testing and imaging (microcomputed tomography) techniques. RESULTS: For the 4 suture-tendon constructs evaluated, maximum and residual displacements were all less than 3 mm. Whether evaluating isolated sutures or suture-tendon constructs, tape-type sutures had smaller displacements than standard #2 sutures when products from the same company were compared. On initial suture passing and after mechanical testing, hole volume was larger in constructs with tape-type rather than standard #2 sutures comparing within the same company. Collectively, constructs with larger hole volumes after mechanical testing had stiffer sutures. The percentage difference in hole volume was larger for standard #2 than tape-type sutures: FiberWire (43%), Ultrabraid (17%), FiberTape (11%), and Ultratape (9%). CONCLUSIONS: Tape-type sutures created larger final holes than standard #2 sutures from the same company. When initially passed through the tendon, tape-type sutures produced larger holes than standard #2 sutures; however, standard #2 sutures enlarged their initially smaller holes more and displaced more than tape-type sutures during cyclic loading, which suggests that tape-type sutures may be protective to suture pulling through tendon.

Gene-expression changes in knee-joint tissues with aging and menopause: implications for the joint as an organ.

BACKGROUND: When considering the "joint as an organ", the tissues in a joint act as complementary components of an organ, and the "set point" is the cellular activity for homeostasis of the joint tissues. Even in the absence of injury, joint tissues have adaptive responses to processes, like aging and menopause, which result in changes to the set point. PURPOSE: The purpose of this study in a preclinical model was to investigate age-related and menopause-related changes in knee-joint tissues with the hypothesis that tissues will change in unique ways that reflect their differing contributions to maintaining joint function (as measured by joint laxity) and the differing processes of aging and menopause. METHODS: Rabbit knee-joint tissues from three groups were evaluated: young adult (gene expression, n=8; joint laxity, n=7; water content, n=8), aging adult (gene expression, n=6; joint laxity, n=7; water content, n=5), and menopausal adult (gene expression, n=8; joint laxity, n=7; water content, n=8). Surgical menopause was induced with ovariohysterectomy surgery and gene expression was assessed using reverse-transcription quantitative polymerase chain reaction. RESULTS: Aging resulted in changes to 37 of the 150 gene-tissue combinations evaluated, and menopause resulted in changes to 39 of the 150. Despite the similar number of changes, only eleven changes were the same in both aging and menopause. No differences in joint laxity were detected comparing young adult rabbits with aging adult rabbits or with menopausal adult rabbits. CONCLUSION: Aging and menopause affected the gene-expression patterns of the tissues of the knee joint differently, suggesting unique changes to the set point of the knee. Interestingly, aging and menopause did not affect knee-joint laxity, suggesting that joint function was maintained, despite changes in gene expression. Taken together, these findings support the theory of the joint as an organ where the tissues of the joint adapt to maintain joint function.

Long-term outcomes of the Bankart and Latarjet repairs: a systematic review.

The most common surgical techniques for the treatment of recurrent anterior shoulder instability include the arthroscopic Bankart repair, the open Bankart repair and the open Latarjet procedure. The purpose of this study was to evaluate and compare the long-term outcomes following these procedures. A systematic review of modern procedures with a minimum follow-up of 5 years was completed. The objective outcome measures evaluated were post-operative dislocation and instability rate, the Rowe score, radiographic arthritis and complications. Twenty-eight studies with a total of 1652 repairs were analyzed. The estimated re-dislocation rate was 15.1% following arthroscopic Bankart repair, 7.7% following open Bankart repair and 2.7% following Latarjet repair, with the comparison between arthroscopic Bankart and open Latarjet reaching statistical significance (p<0.001). The rates of subjective instability and radiographic arthritis were consistently high across groups, with no statistical difference between groups. Estimated complication rates were statistically higher in the open Latarjet repair (9.4%) than in the arthroscopic Bankart (0%; p=0.002). The open Latarjet procedure yields the most reliable method of stabilization but the highest complication rate. There are uniformly high rates of post-operative subjective instability symptoms and radiographic arthritis at 5 years regardless of procedure choice.

Graft Augmentation Versus Bridging for Large to Massive Rotator Cuff Tears: A Systematic Review.

PURPOSE: To systematically review the literature on the healing rates and clinical outcomes of the 2 different graft indications (i.e., augmentation vs bridging) during rotator cuff repair. METHODS: A systematic literature review was performed for clinical studies of rotator cuff repair using grafts for large to massive tears. The primary outcome was tendon healing on either magnetic resonance imaging or ultrasound. The secondary outcomes included visual analog scale for pain, American Shoulder and Elbow Surgeons score, and University of California at Los Angeles score, and forward elevation. Studies were divided into augmentation and bridging groups, and outcomes were compared statistically. RESULTS: Twelve studies with 13 study groups were included: 167 repairs in the augmentation group and 247 repairs in the bridging group. For augmentation and bridging groups, the mean age was 62.2 and 62.8 years and the mean follow-up was 28.5 and 37.7 months, respectively. The estimated healing rates were 64.0% for augmentation and 77.9% for bridging. Although both procedures had improved clinical outcomes, no statistical difference between groups was detected except lower visual analog scale in the bridging group at follow-up. CONCLUSIONS: Bridging grafts had no significant difference in healing or clinical outcomes when compared with a graft used for augmentation. Bridging grafts may be considered for this difficult patient population with large to massive rotator cuff tears. LEVEL OF EVIDENCE: Level IV, systematic review of Level II to IV studies.

Arthroscopic Repair of Articular Surface Partial-Thickness Rotator Cuff Tears: Transtendon Technique versus Repair after Completion of the Tear-A Meta-Analysis.

Articular surface partial-thickness rotator cuff tears (PTRCTs) are commonly repaired using two different surgical techniques: transtendon repair or repair after completion of the tear. Although a number of studies have demonstrated excellent clinical outcomes, it is unclear which technique may provide superior clinical outcomes and tendon healing. The purpose was to evaluate and compare the clinical outcomes following arthroscopic repair of articular surface PTRCT using a transtendon technique or completion of the tear. A systematic review of the literature was performed following PRISMA guidelines and checklist. The objective outcome measures evaluated in this study were the Constant Score, American Shoulder and Elbow Surgeons score, Visual Analogue Scale, physical examination, and complications. Three studies met our criteria. All were prospective randomized comparative studies with level II evidence and published from 2012 to 2013. A total of 182 shoulders (mean age 53.7 years; mean follow-up 40.5 months) were analyzed as part of this study. Both procedures provided excellent clinical outcomes with no significant difference in Constant Score and other measures between the procedures. Both procedures demonstrated improved clinical outcomes. However, there were no significant differences between each technique. Further studies are required to determine the long-term outcome of each technique.

Increased lubricin/proteoglycan 4 gene expression and decreased modulus in medial collateral ligaments following ovariohysterectomy in the adult rabbit: Evidence consistent with aging.

This study investigated whether ovariohysterectomy (OVH) surgery to induce menopause resulted in changes to modulus, failure strain and lubricin/proteoglycan 4 (PRG4) gene expression in rabbit medial collateral ligaments (MCLs), similar to aging (Thornton et al., 2015a). The MCLs from adult rabbits that underwent OVH surgery as adolescents (15-week-old) and adults (1-year-old) were compared by evaluating mechanical behaviour (adolescent OVH, n=8; adult OVH, n=7; normal, n=7), gene expression (adolescent OVH, n=9; adult OVH, n=8; normal, n=8), and collagen and glycosaminoglycan (adolescent OVH, n=9; adult OVH, n=8; normal, n=8) and water (adolescent OVH, n=9; adult OVH, n=8; normal, n=8) content. Mechanical behaviour evaluated cyclic, static and total creep strain, and ultimate tensile strength, modulus and failure strain. The RT-qPCR assessed mRNA levels for matrix regulatory genes. Adult OVH MCLs exhibited increased cyclic creep and failure strain, and decreased modulus with increased mRNA levels for lubricin/PRG4 and collagen I compared with normal MCLs. Adolescent OVH MCLs exhibited increased cyclic, static and total creep strain with decreased mRNA levels for the progesterone receptor. Lubricin/PRG4 plays a role in the lubrication of collagen fascicles which is likely related to the decreased modulus and increased failure strain observed in ligaments from adult OVH rabbits. Progesterone and its receptor are thought to play a role in the stretching of ligaments in pelvic organ prolapse and pregnancy which is likely related to the increase in creep strain observed in ligaments from adolescent OVH rabbits. Ovariohysterectomy in adult rabbits resulted in changes that were consistent with the aging MCL.

Can Grafts Provide Superior Tendon Healing and Clinical Outcomes After Rotator Cuff Repairs?: A Meta-analysis.

BACKGROUND: Arthroscopic repair of large to massive rotator cuff tears commonly retear. To improve healing rates, a number of different approaches have been utilized, including the use of grafts, which may enhance the biomechanical and biologic aspects of the repair construct. However, the outcomes after the use of grafts are diverse. PURPOSE: To systematically review the literature for large to massive rotator cuff tears to determine whether the use of grafts generally provides superior tendon healing and clinical outcomes to the repairs without grafts. STUDY DESIGN: Systematic review; Level of evidence, 3. METHODS: A systematic review of the literature was performed. Clinical studies comparing the repairs with (graft group) and without grafts (control group) were included and analyzed. The primary outcome was tendon healing on either magnetic resonance imaging or ultrasound. The secondary outcome measures included visual analog scale for pain, University of California at Los Angles (UCLA) score, and forward elevation range. Differences between groups in all outcome measures were statistically analyzed. RESULTS: Six comparative studies (level of evidence 2 or 3) with 13 study groups were included. A total of 242 repairs in the graft group (mean age, 62.5 ± 4.6 years) and 185 repairs in the control group (mean age, 62.5 ± 5.0 years) were analyzed. The graft types utilized included autograft (fascia lata) in 1 study, allograft (human dermis) in 2 studies, xenograft (bovine pericardium, porcine small intestine submucosa) in 2 studies, synthetic graft (polypropylene) in 1 study, and a combination of autograft (the long head of biceps) and synthetic graft (polypropylene) in 1 study. The overall mean follow-up time was 28.4 ± 9.0 months. When 1 or 2 studies/study groups were excluded due to practical or statistical reasons, the graft group demonstrated significantly improved healing (odds ratio, 2.48; 95% CI, 1.58-3.90; P < .0001) and all clinical outcome measures at final follow-up (P ≤ .02). CONCLUSION: The use of grafts generally provides superior tendon healing and clinical outcomes compared to repairs without grafts, except for some specific graft types (eg, porcine small intestine submucosa, bovine pericardium). Further investigations are required to determine the benefits of the use of grafts.

Magnetic resonance imaging arthrography following type II superior labrum from anterior to posterior repair: interobserver and intraobserver reliability.

BACKGROUND: Arthroscopic repair of type II superior labrum from anterior to posterior (SLAP) lesions is a common surgical procedure. However, anatomic healing following repair has rarely been investigated. The intraobserver and interobserver reliability of magnetic resonance imaging arthrography (MRA) following type II SLAP repair has not previously been investigated. This is of particular interest due to recent reports of poor clinical results following type II SLAP lesion repair. PURPOSE: To evaluate the MRA findings following arthroscopic type II SLAP lesion repair and determine its intraobserver and interobserver reliability. STUDY DESIGN: Cohort study (diagnosis), Level of Evidence, 2. METHODS: Twenty-five patients with an isolated type II SLAP lesion (confirmed via diagnostic arthroscopy) underwent standard suture anchor-based repair. At a mean of 25.2 months post-operatively, patients underwent a standardized MRA protocol to investigate the integrity of the repair. MRAs were independently reviewed by two radiologists and a fellowship trained shoulder surgeon. The outcomes were classified as healed SLAP repair or re-torn SLAP repair. RESULTS: On average, 54% of MRAs were interpreted as healed SLAP repairs while 46% of MRAs were interpreted as having a re-torn SLAP repair. Overall, only 43% of the studies had 100% agreement across all interpretations. The intraobserver reliability ranged from 0.71 to 0.81 while the interobserver reliability between readers ranged from 0.13 to 0.44 (Table 1). CONCLUSION: The intraobserver agreement of MRA in the evaluation of type II SLAP repair was substantial to excellent. However, the interobserver agreement of MRA was poor to fair. As a result, the routine use of MRA in the evaluation of type II SLAP lesion repair should be utilized with caution. A global evaluation of the patient, including detailed history and physical examination, is paramount in determining the cause of failure and one should not rely on MRA alone.