Hamstring Tendon Autograft Is Associated With Increased Knee Valgus Moment After Anterior Cruciate Ligament Reconstruction: A Biomechanical Analysis

BACKGROUND

There is limited evidence related to the effects of autograft type on functional performance after anterior cruciate ligament reconstruction (ACLR).

PURPOSE/HYPOTHESIS

This study aimed to compare biomechanical outcomes during a drop vertical jump (DVJ) between patients with a hamstring tendon (HT) autograft, quadriceps tendon (QT) autograft with bone block, QT autograft without bone block, and bone-patellar tendon-bone autograft at 6 months postoperatively in an adolescent population. The authors' hypothesized there would be differences in DVJ biomechanics between athletes depending on the type of autograft used.

STUDY DESIGN

Controlled laboratory study.

METHODS

Patients aged 8 to 18 years who underwent primary ACLR were included for analysis. Kinematic and kinetic data collected during a DVJ using a 3-dimensional computerized marker system were assessed at 6 months after ACLR and compared with the uninjured contralateral limb.

RESULTS

A total of 155 participants were included. There were no significant differences in terms of age, sex, or affected leg (P≥ .1973) between groups. The HT group was significantly associated with a larger knee valgus moment at initial contact compared with the QT group (28 × 10-2 vs -35 × 10-2 N·m/kg, respectively; P = .0254) and a significantly larger maximum hip adduction moment compared with the QT with bone block group (30 × 10-2 vs -4 × 10-2 N·m/kg, respectively; P = .0426). Both the QT with bone block (-12 × 10-2 vs -3 × 10-2 N·m/kg, respectively; P = .0265) and QT (-13 × 10-2 vs -3 × 10-2 N·m/kg, respectively; P = .0459) groups demonstrated significantly decreased mean knee extension moments compared with the HT group.

CONCLUSION

The findings of this study suggest that utilizing an HT autograft resulted in a significantly increased knee valgus moment at initial contact compared with a QT autograft without bone block at 6 months after ACLR in adolescent patients performing a DVJ. A QT autograft was found to be associated with significantly decreased extensor mechanism function compared with an HT autograft.

CLINICAL RELEVANCE

This study adds unique kinematic and kinetic information regarding various ACLR autograft options and highlights the biomechanical deficits that should be taken into consideration in rehabilitation.

Radiofrequency in arthroscopic shoulder surgery: a systematic review

BACKGROUND

Radiofrequency has seen an increase in use in orthopedics including cartilage lesion debridement in the hip and knee as well as many applications in arthroscopic shoulder surgery. The purpose of this systematic review is to evaluate the safety and usage of radiofrequency in the shoulder.

METHODS

This systematic review was registered with PROSPERO (international registry) and followed the preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) guidelines. Embase and PubMed were searched using: "shoulder," "rotator cuff," "biceps," "acromion" AND "monopolar," "bipolar," "ablation," "coblation," and "radiofrequency ablation." The title and abstract review were performed independently. Any discrepancies were addressed through open discussion.

RESULTS

A total of 63 studies were included. Radiofrequency is currently utilized in impingement syndrome, fracture fixation, instability, nerve injury, adhesive capsulitis, postoperative stiffness, and rotator cuff disease. Adverse events, namely superficial burns, are limited to case reports and case series, with higher-level evidence demonstrating safe use when used below the temperature threshold. Bipolar radiofrequency may decrease operative time and decrease the cost per case.

CONCLUSIONS

Shoulder radiofrequency has a wide scope of application in various shoulder pathologies. Shoulder radiofrequency is safe; however, requires practitioners to be cognizant of the potential for thermal burn injuries. Bipolar radiofrequency may represent a more efficacious and economic treatment modality. Safety precautions have been executed by institutions to cut down patient complications from shoulder radiofrequency. Future research is required to determine what measures can be taken to further minimize the risk of thermal burns.

Strains/Sprains and Fractures Are the Most Common Hand and Wrist Injuries in National Basketball Association Athletes Who Return to Preinjury Player Efficiency and Equal or Greater True Shooting Percentage Within Two Years of Injury

Purpose

To characterize the prevalence and incidence of in-game hand and wrist injuries in the National Basketball Association (NBA), to determine the factors associated with an equal or greater player efficiency rating (PER), and to determine the factors associated with an equal or greater true shooting percentage (TS%) 2 years after a hand and wrist injury using a large-scale national database of NBA players.

Methods

Injury data from seasons 2015-2016 to 2020-2021, with exclusion of the 2019-2020 because of abbreviated play due to the coronavirus disease 2019, were extracted from a public online database, Pro Sports Transactions. Injury characteristics and NBA player demographic information were assessed using descriptive statistics. Poisson logistic regression analyses were performed to identify risk factors associated with equal or increased PER and TS% 2years after injury.

Results

There were 214 reported hand and wrist injuries, and of these injuries, 173 (81%) were classified as structural. The most common injury types were a strain or sprain (0.63 per 1,000 game exposures), followed by fractures (0.37 per 1,000 game exposures). Older age (relative risk [RR] 0.89; 95% confidence interval [CI] 0.84-0.95) and more years played in the NBA were modestly associated with relative risk of having a decreased PER at 2 years after injury. Increased weight (RR 1.02; 95% CI 1-1.05) and increased body mass index (RR 1.14; 95% CI 1.01-1.29) were also modestly associated with having a decreased PER and TS%, respectively at 2 years after injury.

Conclusions

Strains/sprains and fractures are the most common hand and wrist injuries sustained by NBA players. Regardless of dominant or nondominant hand and wrist injuries, NBA players are likely to return to baseline overall player efficiency based on PER and TS% within 2 years of injury.

Clinical Relevance

Our study characterizes hand and wrist injuries of NBA players and provides an understanding for these injuries on player performance at 2 years.

Characterization of Ankle Injuries and Associated Risk Factors in the National Basketball Association: Minutes Per Game and Usage Rate Associated With Time Loss

Background

Ankle injuries are more common in the National Basketball Association (NBA) compared with other professional sports.

Purpose/Hypothesis

The purpose of this study was to report the incidence and associated risk factors of ankle injuries in NBA athletes. It was hypothesized that factors associated with an increased physiologic burden, such as minutes per game (MPG), usage rate, and associated lower extremity injury, would be associated with increased ankle injury risk and time loss.

Study Design

Descriptive epidemiology study.

Methods

Ankle injury data from the 2015-2016 through 2020-2021 NBA seasons were evaluated. The truncated 2019-2020 season due to the COVID-19 pandemic was omitted. The primary outcome was the incidence of ankle injuries, reported per 1000 game-exposures (GEs). Secondary analysis was performed to identify risk factors for ankle injuries through bivariate analysis and multivariable logistic regression of player demographic characteristics, performance statistics, injury characteristics, and previous lower extremity injuries. Factors influencing the time loss after injury were assessed via a negative binomial regression analysis.

Results

A total of 554 ankle injuries (4.06 injuries per 1000 GEs) were sustained by NBA players over 5 NBA seasons, with sprain/strain the most common injury type (3.71 injuries per 1000 GEs). The majority of ankle injury events (55%) resulted in 2 to 10 game absences. The likelihood of sustaining an ankle injury was significantly associated with a greater number of games played (P = .029) and previous injury to the hip, hamstring, or quadriceps (P = .004). Increased length of absence due to ankle injury was associated with greater height (P = .019), MPG (P < .001), usage rate (P = .025), points per game (P = .011), and a prior history of foot (P = .003), ankle (P < .001), and knee injuries (P < .001).

Conclusion

The incidence of ankle injuries was 4.06 per 1000 GEs in professional basketball players. Games played and prior history of hip, hamstring, or quadriceps injuries were found to be risk factors for ankle injuries. Factors associated with physiologic burden such as MPG and usage rate were associated with an increased time loss after injury.

Race and Sex Disparities in Lower Extremity Total Joint Arthroplasty: A Retrospective Database Study

INTRODUCTION

Total joint arthroplasty (TJA) is successful in improving health-related quality of life. However, outcomes vary in the literature due to modifiable and non-modifiable factors. Modifiable factors consist of body mass index (BMI), nutrition, and tobacco use. Non-modifiable risk factors include age, race, sex, and socioeconomic status. Prior literature has focused on racial disparities in terms of the utilization of lower extremity arthroplasty. The purpose of this study is to determine the effect of race and sex on the in-hospital complication rate, length of stay, and charges associated with primary TJA.

METHODS

This retrospective cohort utilized complex survey data from the National Inpatient Sample (NIS) between 2016 and 2019. The use of the International Classification of Disease-10 Procedure Codes (ICD-10 PCS) for right hip, left hip, right knee, and left knee TJA yielded a preliminary total of 2,660,280 patients. The exclusion criteria were bilateral arthroplasty and concomitant unilateral hip and knee arthritis. Major complications were defined as acute myocardial infarction, cardiac arrest, pulmonary embolism, adult respiratory distress syndrome, stroke, shock, and septicemia. Odds ratio (OR) and beta coefficients were adjusted for age, sex, primary payer, hospital region, hospital teaching status, and year. Total charges were adjusted for inflation using the Consumer Price Index data reported by the US Bureau of Labor Statistics.

RESULTS

A total of 2,589,510 patients met our inclusion criteria; 87.6%, 5.9%, 4.8%, 1.4%, and 0.3% of people were 'White', 'Black', 'Hispanic', 'Asian, or Pacific Islander', and 'Native American', as defined by the National (Nationwide) Inpatient Sample (NIS) Variable 'RACE'. Black individuals experienced a significantly greater major complication rate compared to White individuals (0.87% vs. 0.74%, OR 1.25, p-value = 0.0004). Black and Hispanic individuals experienced a significantly greater minor complication rate compared to White individuals (6.39% vs. 4.12%, odds ratio (OR) 1.61, p-value < 0.0001; 4.68% vs. 4.12%, OR 1.17, p-value < 0.0001). Black, Hispanic, Asian or Pacific Islander, and Native American individuals stayed, on average, 0.33, 0.19, 0.19, and 0.25 days longer than White individuals (2.78, 2.54, 2.55, 2.56 vs. 2.37 days, p<0.0001). None of these statistically significant differences exceeded the established minimal clinically important difference of two days. Black, Hispanic, and Asian or Pacific Islander patients were charged $5,751, $18,656, and $12,119 more than White patients ($72,122, $85,027, $78,490, and $59,297 vs. $66,371, p ≤ 0.0165). Native American patients were charged $7,074 less than White patients ($59,297 vs. $66,371, p < 0.0001).

CONCLUSIONS

Black and Hispanic TJA patients may have higher complication rates than White TJA patients. The differences in length of stay between race groups may not affect outcomes. Hispanic patients received significantly more charges than White patients, and Native American patients received significantly fewer charges than White patients after controlling for non-modifiable risk factors. Addressing the charge disparities may reduce the total national cost burden associated with TJA. The present study highlights the need for further studies on healthcare outcomes related to race and sex.

Primary Fibular Osteomyelitis in Children: A Systematic Review

Osteomyelitis of the fibula is rare and is especially rare in children. The published literature is limited to case series and is thus lacking a comprehensive description of the disease. The purpose of this systematic review is to provide the first comprehensive summary of the demographics, presenting symptoms, laboratory values, microbiology, and treatment results of osteomyelitis of the fibula in children based on the existing literature. This institutional review board (IRB)-exempt systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol (PRISMA-P) guidelines. Three search engines were used for a total of 239 studies. Twenty-six studies were screened by full text. Twelve articles underwent a quantitative analysis. Due to limited data and heterogenous reporting, the data were summarized descriptively. The methodologic quality of the studies was evaluated based on the Newcastle-Ottawa scale. The average age was 7.71±3.49 years, and males comprised 57% of the 21 cases. The most common presenting symptoms were fever (86%), antalgic gait (57%), and localized tenderness (81%). The most common site of involvement was the distal third of the fibula (90%). The average C-reactive protein (CRP) was 90.1±38.3 mg/L, and the average erythrocyte sedimentation rate (ESR) was 58.8±21.2 mm/hour. Staphylococcus aureus was the most cultured pathogen reported in 10/21 cases (48%). Open surgery was performed in 17/21 cases (81%), and there were no reported complications. Fever, antalgic gait, and localized tenderness should raise the index of suspicion. Prompt laboratory and radiographic evaluations can help reduce delays in diagnosis and improve outcomes. Blood and tissue cultures are currently performed in about half of the cases. Improvement in our microbiologic diagnosis has the potential to improve antibiotic selection. Local methicillin-resistant Staphylococcus aureus (MRSA) prevalence must be taken into consideration when starting empiric antibiotic treatment. Surgical treatment is often required with a low complication rate. The clinical and laboratory parameters identified in this study have the potential for integration into a composite clinical score.

Continuous Epidural Analgesia Versus Continuous Peripheral Nerve Block in Unilateral Lower Extremity Pediatric Orthopedic Surgery: A Matched Case Comparison Study

Introduction Continuous epidural analgesia (CEA) provides effective postoperative pain relief but includes a substantial side effect profile. Continuous peripheral nerve blocks (CPNBs) have fewer side effects and may quicken ambulation. The purpose of this study was to compare the morphine milligram equivalents (MMEs), need for analgesic rescue, visual analog scale (VAS) pain scores, time to ambulation, postoperative blood pressures, length of stay (LOS), and adverse event rates. Methods This was a matched case comparison study of pediatric patients (ages 8-17) undergoing unilateral lower limb surgery (41 CEA and 36 CPNB). Patients with a history of chronic pain, previous lower extremity surgery, and developmental delay were excluded. The Chi-square test and Student's t-test were used, and p-values < 0.05 were considered significant. Results There were no statistically significant differences in demographics or the American Society of Anesthesiologists (ASA) grade. There were no significant differences in postoperative MMEs, the need for analgesic rescue, or VAS scores on any postoperative day. The CEA group had a longer time to ambulation (2.56 ± 0.93 days versus 1.89 ± 0.69 days, p = 0.004). The CEA group demonstrated a higher number of days of systolic hypotension (0.61 ± 0.97 mmHg versus 0.06 ± 0.23 mmHg, p = 0.0009) and diastolic hypotension (1.90 ± 1.24 mmHg versus 1.00 ± 0.93 mmHg, p = 0.0006). There were no significant differences in the length of stay between the CEA and CPNB groups (5.08 versus 4.24, p = 0.28). There was no statistically significant difference between the rates of pruritus, light-headedness, and altered mental status. The CEA group demonstrated higher rates of nausea (51.2% versus 13.9%, p = 0.001), constipation (36.6% versus 8.3%, p = 0.004), urinary retention (9.8% versus 0%, p = 0.006), and average number of minor adverse events per patient (1.02 versus 0.25, p = 0.002). Conclusions CPNBs and CEAs demonstrate equivalent postoperative opioid use after unilateral lower extremity surgery in the pediatric population. In our population, a low complication rate and a decreased time to ambulation were seen in the CPNB group. There may be certain select scenarios priorly managed with a CEA that can be appropriately managed with a CPNB. A prospective multicenter study incorporating patient satisfaction data could further facilitate the incorporation of CPNB in pediatric pain management protocols after orthopedic surgery.

Prenatal radiographic evaluation of congenital transverse limb deficiencies: A scoping review

BACKGROUND

Congenital transverse deficiencies are horizontal deficiencies of the long bones that occur with a reported incidence as high 0.38%. They can occur alone or represent a manifestation of a various clinical syndromes. Diagnosis has traditionally comprised of conventional radiography and prenatal imaging studies. There has been much advancement regarding prenatal imaging modalities to allow for early diagnosis and appropriate treatment.

AIM

To summarize the current state of knowledge on congenital transverse limb deficiencies and to provide an update regarding the radiographic evaluation of congenital transverse limb deficiencies.

METHODS

This IRB-exempt scoping review followed the PRISMA-ScR checklist for scoping reviews strictly. Five search engines were searched for a total of 265 publications. Four authors reviewed these during the screening process. Of these, 51 studies were included in our article. Prenatal magnetic resonance imaging (MRI), 3D Ultrasound, and multidetector Computed tomography (CT) exist are emerging modalities that have the potential to improve diagnosis.

RESULTS

Use of the appropriate classification system, three-dimensional ultrasonography with a maximum intensity projection, and appropriate use of prenatal MRI and prenatal CT can improve diagnosis and inter-provider communication.

CONCLUSION

Further scholarly efforts are required to develop improve standardized guidelines regarding the pre-natal radiographic evaluation of congenital limb deficiencies.

Medial-Sided Ligamentous Injuries of the Athlete's Knee: Evaluation and Management

The superficial medial collateral ligament (sMCL) is the most commonly injured ligamentous structure in the knee. The other medial knee stabilizers include the deep medial collateral ligament, the posterior oblique ligament, and the medial meniscus. Medial collateral ligament injuries frequently occur in young athletes. As a result of the good healing capacity of the sMCL, the majority of acute medial-sided knee injuries can be treated nonoperatively with good outcomes. However, missed concomitant injuries can lead to residual laxity and instability of the knee when treated conservatively. When surgical management is warranted, numerous techniques exist, including repair, augmentation, and reconstruction. Recent anatomic and biomechanical studies defining the attachment sites and functional roles of the individual medial knee structures have led to advancements in diagnosis, treatment, and rehabilitation. These studies have allowed for the development of an anatomic reconstruction technique that restores the native stability and load-sharing relationships among the medial knee structures. The purpose of this narrative review is to summarize the recent updates in the anatomy, biomechanics, evaluation, and treatment of ligamentous injuries on the medial side of the athlete's knee.

Biomechanical Gender Differences in the Uninjured Extremity After Anterior Cruciate Ligament Reconstruction in Adolescent Athletes: A Retrospective Motion Analysis Study

Introduction Subsequent anterior cruciate ligament (ACL) injury is more common in the pediatric population and encompasses graft failure and subsequent contralateral tears. Females are at a higher risk. The purpose of the present study was to compare the knee valgus angles at initial contact, knee extension moments, anterior and lateral knee joint forces, hip flexion angles, hip adduction moments, and ankle inversion during the drop vertical test in the uninjured extremity between adolescent males and females who had previously undergone an anterior cruciate ligament reconstruction (ACLR). Methods This IRB-approved retrospective chart review included patients aged 8-18 years who were seen at the five to seven month postoperatively following ACL reconstruction. A total of 168 patients met our inclusion criteria (86 girls and 82 boys.) Using three-dimensional motion capture technology (CORTEX software, Motion Analysis Corp., Rohnert Park, CA), data were collected while the subject performed the drop vertical test over floor-mounted force plates (FP-Stairs, AMTI, Watertown, MA) under the direct supervision of a pediatric physical therapist. The Wilcoxon rank sum was used, and p < 0.05 was considered statistically significant. Results Females demonstrated a larger average knee joint extension moment (0.31 vs 0.28 N*m/kg, p = 0.0408), a larger anterior knee joint force at initial contact (3.51 vs. 2.79, N/kg, p = 0.0458), larger average hip flexion angle (41.50° vs. 35.99°, p = 0.0005), a smaller maximum hip adduction moment (0.92 vs. 1.16, N*m/kg, p = 0.0497), and a smaller average ankle inversion angle (5.08° vs. 6.41°, p = 0.03231). No significant differences were found regarding knee abduction angle or lateral knee joint force. Conclusions The biomechanical profile of the contralateral extremity varies significantly between the genders after ACLR. In the uninjured extremity, females may have larger hip flexion angles, smaller hip adduction moments, larger anterior knee joint forces, larger knee extension moments, and smaller ankle inversion angles as compared to males after ACLR. These findings may explain the higher incidence of subsequent contralateral injury in female adolescent athletes. Further work is required to develop a composite score that determines at-risk athletes.

Biomechanical Comparison of Adjustable-Loop Femoral Cortical Suspension Devices for Soft Tissue ACL Reconstruction

Background

Several new adjustable-loop devices (ALDs) for anterior cruciate ligament reconstruction (ACLR) have not been tested in vitro.

Purpose

To compare the biomechanical performances of 5 ALDs under a high cyclic load and forces representative of the return-to-play conditions seen in the recovering athlete.

Study Design

Controlled laboratory study.

Methods

A total of 10 devices for each of 5 chosen ALDs (UltraButton [Smith & Nephew], RigidLoop [DePuy Mitek], ProCinch [Stryker], TightRope [Arthrex], and ToggleLoc [Biomet]) were tested in a device-only model. The devices were secured to a servohydraulic test machine and preconditioned from 10 to 75 N at a rate of 0.5 Hz for 20 cycles. They were then subjected to high cyclic forces (100-500 N for 4000 cycles) and subsequently pulled to failure at 50 mm/min. The preconditioning displacement, permanent deformation, cumulative peak displacement, stiffness coefficient, and load to failure data were collected.

Results

The UltraButton displayed the greatest preconditioning displacement (0.22 ± 0.20 mm), followed by the RigidLoop (0.11 ± 0.03 mm), ProCinch (0.07 ± 0.04 mm), TightRope (0.07 ± 0.02 mm), and ToggleLoc (0.02 ± 0.03 mm). The TightRope displayed the greatest permanent deformation (3.19 ± 1.03 mm) followed by the UltraButton (2.14 ± 0.92 mm), ToggleLoc (2.02 ± 1.09 mm), RigidLoop (1.67 ± 0.1 mm), and ProCinch (1.38 ± 0.18 mm). The TightRope displayed the greatest cumulative peak displacement (3.69 ± 1.03 mm) followed by the UltraButton (2.46 ± 0.92 mm), ToggleLoc (2.37 ± 1.08 mm), RigidLoop (2.01 ± 0.1 mm), and ProCinch (1.75 ± 0.19 mm). The UltraButton displayed the largest stiffness coefficient (1347.22 ± 136.33 N/mm) followed by the RigidLoop (1325.4 ± 116.37 N/mm), ToggleLoc (1216.62 ± 131.32 N/mm), ProCinch (1155.56 ± 88.04), and TightRope (848.48 ± 31.94). The ToggleLoc displayed the largest load to failure (1874.42 ± 101.08 N) followed by the RigidLoop (1614.12 ± 129.11 N), UltraButton (1391.69 ± 142.04 N), ProCinch (1384.85 ± 58.62 N), and TightRope (991.8 ± 51.1 N.).

Conclusion

The 5 ALDs exhibited different biomechanical properties. None of them had peak cumulative displacements for which the confidence interval lay above 3 mm, thus no single device was determined to have a higher rate of clinical failure compared with the others.

Clinical Relevance

ALD choice may affect biomechanics after ACLR.

An Analysis of Global Orthopedic Organizations Through the Lens of the Four Pillars of Global Surgery

Introduction The mortality of orthopedic trauma is very high, however, a large proportion is considered preventable. Global orthopedics was historically centered around the direct delivery of nonsurgical and surgical medical care. There has been an evolution towards increased sustainability. Purpose The purpose of this paper is to evaluate the accomplishment of the four pillars of global surgery by five commonly referenced orthopedic global surgery organizations. Methods This institutional review board (IRB)-exempt cross-sectional data studied Global Orthopedic Alliance, Operation Rainbow, the Institute for Global Orthopaedics and Traumatology (IGOT), One World Surgery (OWS), and the Canadian Orthopedic Association for Global Surgery (COAGS) through the lens of the four pillars of global surgery: knowledge exchange, advocacy, research initiative, surgical education. The knowledge exchange pillar was examined through the three most popular online knowledge exchange platforms in orthopedics. The advocacy pillar was examined through each organization's individually created website. The research initiative was examined through a comprehensive literature search. The surgical education pillar was examined through resident-level educational resources. The data was summarized descriptively. Results A total of four organizations demonstrated activity within the pillar of knowledge exchange. A total of three organizations demonstrated activity with the pillar of advocacy. A total of three groups demonstrated activity within the pillar of the research initiative. A total of two groups had activity within the pillar of surgical education. Conclusions The landscape regarding global orthopedic surgery programs has evolved greatly to encompass the four pillars of global surgery. Within the past 10 years, there has been increased emphasis on the knowledge exchange and research initiative pillars. Surgical education remains the pillar with the least emphasis. As global orthopedic surgery programs continue to evolve, increasing emphasis should be placed on all four of these pillars to increase sustainability.

Femoral-Sided Avulsion Fracture of the Anterior Cruciate Ligament in a Skeletally Immature Patient: A Case Report

CASE

A 10-year-old boy presented to the clinic with sharp left knee pain after sustaining an injury while hiking. The patient was unable to bear weight. Physical examination demonstrated a moderate effusion and lateral joint line tenderness. Imaging studies revealed a femoral-sided avulsion of the anterior cruciate ligament. Arthroscopic suture fixation of the avulsed fragment resulted in good radiographic and clinical results at the 13-month follow-up.

CONCLUSION

Physeal-sparing suture-fixation of femoral-sided anterior cruciate ligament avulsion injuries can be performed using an all-arthroscopic approach and may be a viable treatment option.

Current applications of gait analysis after total knee arthroplasty: A scoping review

Introduction

The biomechanics of the knee do not return to normal after knee replacement. The purpose of this scoping review is to summarize the current use of gait analysis in total knee arthroplasty and to identify the preoperative motion analysis parameters for which a systematic review aimed at determining the reliability and validity may be warranted.

Materials and methods

This IRB-exempt scoping review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist. The 279 articles from the five search engines underwent a title/abstract and full-text screening. Included articles were categorized as either: the role of gait analysis as a research tool for operative decisions, other research applications for motion analysis in total knee arthroplasty, gait analysis as a tool in predicting radiologic outcomes, or gait analysis as a tool in predicting clinical outcomes.

Results

Eleven articles studied gait analysis as a research tool in studying operative decisions. Five articles studied other research applications for motion analysis in total knee arthroplasty. Other research applications for motion analysis currently include studying the role of the unicompartmental knee arthroplasty and novel physical therapy protocols aimed at optimizing post-operative care. Two articles studied motion analysis as a tool for predicting radiographic outcomes. 15 articles studied motion analysis in conjunction with clinical scores.

Conclusions

There is a broad range of research applications for motion analysis in knee reconstruction. Current limitations include vague definitions of 'gait analysis' or 'motion analysis' and a limited number of articles with preoperative and postoperative outcomes. Knee adduction moment, knee adduction impulse, total knee range of motion, varus angle, cadence, stride length, and velocity have the potential for integration into composite clinical scores. A systematic review to determine the psychometric properties of these variables is warranted.

Clinical Results Following Conservative Management of Tarsal Tunnel Syndrome Compared With Surgical Treatment: A Systematic Review

Introduction

Posterior tarsal tunnel syndrome involves entrapment of the posterior tibial nerve as it travels in the groove posterior to the medial malleolus. Conventional wisdom dictates that patients with tarsal tunnel syndrome be treated with conservative treatment and medical management, with surgical options available for patients with refractory symptoms and good candidacy. Minimally invasive options for neuropathic entrapment syndromes have developed in recent years and may provide a therapeutic role in tarsal tunnel syndrome.

Objective

The present investigation provides a summary of the current state of knowledge on tarsal tunnel syndrome and a comparison between minimally invasive and surgical treatment options.

Methods

The literature search was performed in Mendeley. Search fields were varied until redundant. All articles were screened by title and abstract and a preliminary decision to include an article was made. A full-text screening was performed on the selected articles. Any question regarding the inclusion of an article was discussed by 3 authors until an agreement was reached.

Results

Most commonly tarsal tunnel syndrome is idiopathic. Other reported causes include post-traumatic, lipomas, cysts, ganglia, schwannomas, ganglia, varicose plantar veins, anatomic anomalies, and systematic inflammatory conditions. Several risk factors have been described including female gender, athletic participation, hypothyroidism, diabetes mellitus, systemic sclerosis, chronic renal failure, and hemodialysis use. A few recent studies demonstrate anatomic variants that have not previously been summarized. Three articles describe clinical outcomes after conservative treatment with acceptable results for first line treatment. Two primary articles report on the use of minimally invasive treatment for tarsal tunnel syndrome. Fourteen articles report on the clinical outcomes after surgical management.

Conclusion

Clinical understanding of tarsal tunnel syndrome has evolved significantly, particularly with regards to the pathoanatomy of the tarsal canal over the past twelve years. A few novel anatomic studies shed light on variants that can be helpful in diagnosis. Conservative management remains a good option that can resolve the symptoms of many patients. As more prospective cohorts and clinical trials are performed on minimally invasive options, pulsed radiofrequency and neuromodulation may evolve to play a larger role in the treatment of this condition. Currently, surgical treatment is only pursued in a very select group of patients with refractory symptoms that do not respond to medical or minimally invasive options. Surgical outcomes in the literature are good and current evidence is stronger than that for minimally invasive options.

Treatment and Management of Xiphoidalgia

Xiphodynia is a rare but debilitating condition that can be described as a form of pain on the xiphisternal joint or any related structures that are anchored to the xiphoid process. Although xiphodynia is a musculoskeletal pain in nature, the pain located in the anterior chest can commonly mislead physicians into pursuing other diagnoses such as cardiac diseases. This leads to a prolonged duration of pain before receiving treatment. In the attempt to alleviate pain resulting from this condition, physicians have previously utilized a range of treatment options, including conservative management, injections, or in severe cases, xiphoidectomy. In this review, we aim to give a brief overview of xiphodynia, including clinical diagnoses and current treatment modalities.

Key Summary Points

1. Xiphodynia can be described as pain radiating from an irritated xiphoid process that can travel to the chest, abdomen, throat, and arms2. Risk factors for developing secondary xiphoidalgia include GERD, gall-bladder disease, angina pectoris, and coronary-artery disease3. The treatment of xiphodynia can range from conservative management to injections or a xiphoidectomy4. Further research is required to develop a standardized treatment protocol and currently the choice of treatment depends on the patient's individual case and the degree of severity.

Back pain in adolescent athletes: a narrative review

BACKGROUND

Back pain in young athletes is common. Adolescents are at an increased risk for back pain related to several factors including rapid growth. Traditionally, the conversation around back pain in the adolescent age group has been centered around diagnosis and treatment; however, there are emerging studies regarding prevention.

OBJECTIVE

The purpose of the present investigation is to summarize sport-specific risk factors, to describe the growing emphasis on prevention/screening, and report results on minimally invasive and surgical options.

METHODS

The literature search was performed in Mendeley. Search fields were varied until redundant. All articles were screened by title and abstract and a preliminary decision to include an article was made. The full-text screening was performed on the selected articles. Any question regarding the inclusion of an article was discussed by at least 3 authors until an agreement was reached.

RESULTS

Adolescent athletes have a higher risk of developing spondylolysis and spondylolisthesis than their non-athletic counterparts. Participation in athletic activity alone, increased body mass index, varsity status, and nationally/internationally competitive status are identified are demographic risk factors. Weightlifters, gymnasts, football players, and combat athletes may be at higher risks. Increased lumbar lordosis, abdominal muscle weakness, hip flexor tightness, hamstring tightness, thoracolumbar fascia tightness, femoral anteversion, genu recurvatum, and thoracic kyphosis also predispose. Recent cadaveric and kinematic studies have furthered our understanding of pathoanatomic. There is some evidence to suggest that isokinetic testing and electromyographic data may be able to identify at-risk individuals. Perturbation-based exercise interventions can reduce the incidence of adolescent athletic back pain. There is a large body of evidence to support the efficacy of physical therapy. There is some data to support minimally invasive treatments including external bone growth simulators, steroid injections, and chemonucleolysis for specific pathologies. Endoscopic surgery results for a limited subset of patients with certain disease processes are good.

CONCLUSIONS

Back pain in adolescent athletes is common and may not lead to appropriate alterations in athletes' level of participation. Athletes with a higher body mass index should be counseled regarding the benefits of losing weight. Isokinetic testing and electromyographic data have the potential as diagnostic and screening tools. Strength deficits and postural control could be used to identify patients requiring early intervention and thus reduce the incidence. External bone growth simulators, steroid injections, and chemonucleolysis could potentially become conservative options in the future. When surgery is indicated, the endoscopic intervention has the potential to decrease operative time, decrease cost, and promote healing.

Liposomal Bupivacaine Decreases Post-Operative Opioid Use after Anterior Cruciate Ligament Reconstruction: A Review of Level I Evidence

Introduction

Anterior Cruciate Ligament tears are common after a non-contact injury and several thousand reconstructions (ACLR) occur yearly in the United States. Multimodal pain management has evolved greatly to include nerve blocks to minimize physical therapy losses post-operatively, pericapsular and wound injections, and other adjunctive measures. However, there is a surprisingly high use of opioid use after ACLR.

Objective

The purpose of present investigation is to summarize the current state of knowledge regarding opioid use after ACLR and to synthesize the literature regarding the use of liposomal bupivacaine and its potential to reduce post-operative opioid use in ACLR patients.

Methods

The literature search was performed in Mendeley. Search fields were varied until redundant. All articles were screened by title and abstract and a preliminary decision to include an article was made. A full-text screening was performed on the selected articles. Any question regarding the inclusion of an article was discussed by three authors until an agreement was reached.

Results

Eighteen articles summarized the literature around the opioid epidemic in ACL surgery and the current context of multimodal pain strategies in ACLR. Five primary articles directly studied the use of liposomal bupivacaine as compared to reasonable control options. There remains to be over prescription of opioids within orthopedic surgery. Patient and prescriber education are effective methods at decreasing opioid prescriptions. Many opioid pills prescribed for ACLR are not used for the correct purpose. Several risk factors have been identified for opioid overuse in ACLR: American Society of Anesthesiologists score, concurrent meniscal/cartilage injury, preoperative opioid use, age < 50, COPD, and substance abuse disorder. Liposomal bupivacaine is effective in decreasing post-operative opioid use and reducing post-operative pain scores as compared to traditional bupivacaine. LB may also be effective as a nerve block, though the data on this is more limited and the effects on post-operative therapy need to be weighed against the potential therapeutic benefit. LB is associated with significantly greater costs than traditional bupivacaine.

Discussion

The role for opioid medications in ACLR should continue to decrease over time. Liposomal bupivacaine is a powerful tool that can reduce post-operative opioid consumption in ACLR.

Pathoanatomy, biomechanics, and treatment of upper cervical ligamentous instability: A literature review

BACKGROUND

Cervical spine instability broadly refers to compromise of the articular congruity. It can be stratified according to spinal level, functional compromise, and mechanism of instability. Conventional wisdom advocates for use of bracing and physical therapy with only a subset of patients proceeding to obtain surgical treatment.

OBJECTIVE

The purpose of this review article is to summarize the current state of knowledge on upper cervical ligamentous instability.

METHODS

The literature search was performed in Mendeley. Search fields were varied until redundant. All articles were screened by title and abstract and a preliminary decision to include an article was made. The full-text screening was performed on the selected articles. Any question regarding the inclusion of an article was discussed by 3 authors until an agreement was reached.

RESULTS

Many articles report on the etiological factors including ligamentous laxity, traumatic injury, syndrome instability, iatrogenic instability, congenital, and inflammatory causes. A few recent studies elucidate new findings regarding pathoanatomy through the use of finite element analysis. A few articles demonstrate the diagnosis and show that radiographs alone have a low diagnostic rate and that functional MRI may be able to better quantify instability. Conservative treatment has been described, but there are no outcome studies in the literature. Surgical treatment has been described in many different populations with good radiologic and clinical outcomes. Recently the use of preoperative 3D CT reconstruction has been described with radiographic and immediate postoperative patient-reported outcomes.

CONCLUSION

The presentation of upper cervical spinal instability can be asymptomatic, symptoms of isolated instability, symptoms of nerve irritation, vertebrobasilar insufficiency, or severe neurologic compromise. 3D fine element analysis models and motion-capture systems have the potential to increase our understanding of the pathoanatomic cascade in both traumatic and non-traumatic cases of upper cervical spinal instability. A few modalities on the horizon could increase diagnostic potential. More efforts are needed regarding the use of fine element analysis in understanding the pathoanatomic cascade, the long-term outcomes of children over a spectrum of syndromic causes, and the potential of preoperative virtual simulation to improve surgical outcomes.

Outcomes after minimally invasive and surgical management of suprascapular nerve entrapment: A systematic review

Background

The prevalence of suprascapular neuropathy is higher than previously estimated. Recent literature highlights a myriad of treatment options for patients ranging from conservative treatment and minimally invasive options to surgical management. However, there are no comprehensive review articles comparing these treatment modalities.

Objective

The purpose of this review article is to summarize the current state of knowledge on suprascapular nerve entrapment and to compare minimally invasive treatments to surgical treatments.

Methods

The literature search was performed in Mendeley. Search fields were varied redundant. All articles were screened by title and abstract and a preliminary decision to include an article was made. A full-text screening was performed on the selected articles. Any question regarding the inclusion of an article was discussed by 3 authors until an agreement was reached.

Results

Recent studies have further elucidated the pathoanatomy and described several risk factors for entrapment ranging. Four studies met our inclusion criteria regarding peripheral nerve stimulation with good pain and clinical outcomes. Two studies met our inclusion criteria regarding pulsed radiofrequency and showed promising pain and clinical outcomes. One study met our inclusion criteria regarding transcutaneous electrical nerve stimulation and showed good results that were equivalent to pulsed radiofrequency. Surgical treatment has shifted to become nearly all arthroscopic and surgical outcomes remain higher than minimally invasive treatments.

Conclusions

Many recently elucidated anatomical factors predispose to entrapment. A history of overhead sports or known rotator cuff disease can heighten a clinician’s suspicion. Entrapment at the suprascapular notch is more common overall, yet young athletes may be predisposed to isolated spinoglenoid notch entrapment. Pulsed radiofrequency, peripheral nerve stimulation, and transcutaneous electrical nerve stimulation may be effective in treating patients with suprascapular nerve entrapment. Arthroscopic treatment remains the gold-standard in patients with refractory entrapment symptoms.

The role for high volume local infiltration analgesia with liposomal bupivacaine in total hip arthroplasty: A scoping review

Introduction

Liposomal bupivacaine has been integrated into clinical practice within many surgical disciplines to reduce post-operative pain and opioid consumption. This novel agent has been utilized in this regard in many subdisciplines of orthopedic surgery. Total hip arthroplasty has significant opioid use post-operatively as compared to many other orthopedic disciplines.

Objectives

The purpose of the present investigation is to summarize the current use of liposomal bupivacaine after total hip arthroplasty and to shed light on the prospect of liposomal bupivacaine to reduce opioid use after total hip arthroplasty. A tertiary purpose is to identify future areas of adjunctive pain measures that can assist in the reduction of opioid use after total hip arthroplasty.

Methods

This IRB-exempt scoping review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist strictly. The literature search was performed in Mendeley. Search fields were varied until redundant. All articles were screened by title and abstract and a preliminary decision to include an article was made. The full-text screening was performed on the selected articles. Any question regarding the inclusion of an article was discussed by three authors until an agreement was reached.

Results

A total of 21 articles were included for qualitative description of the opioid epidemic, opioid overuse in total hip arthroplasty, and risk factors for opioid overuse in total hip arthroplasty. A total of 9 articles were included regarding the use of liposomal bupivacaine in total hip arthroplasty. Several risk factors have been identified for opioid overuse after total hip arthroplasty. These include younger age, an opioid risk tool score of > 7, a higher body mass index, chronic obstructive pulmonary disease, immunodeficiency syndromes, preexisting pain syndromes, peripheral vascular disease, anxiety and mood disorders, and substance abuse disorders. Liposomal bupivacaine reduces postoperative opioid use, patient-reported outcomes, length of stay, and time to ambulation, yet is more expensive than traditional bupivacaine.

Conclusions

Liposomal bupivacaine represents a useful adjunct for multimodal pain strategies in total hip arthroplasty with sufficient evidence to suggest that it may be useful in decreasing postoperative opioid use. The high costs of LB represent a barrier to institutional acceptance of LB into standardized multimodal pain strategies. Further efforts should be aimed toward better understanding the current state of integration of LB into academic and private practice settings, industry movements to decrease the cost, and the role other adjunctive measures may have in reducing post-operative opioid use.

Clinical Scores Predict Acute and Chronic Complications in Pediatric Osteomyelitis: An External Validation

BACKGROUND

Pediatric acute hematogenous osteomyelitis (AHO) outcomes are highly dependent on the disease severity. Recently, the A-SCORE and C-SCORE, were proposed as predictors of an acute complicated course and chronic morbidity, respectively. The purpose of this study was to externally validate the A-SCORE and C-SCORE at a single institution.

METHODS

This IRB-approved retrospective chart review included AHO patients admitted at a tertiary referral hospital between October 1, 2015 and December 31, 2019. The inclusion criteria were ages 0 to 18 and clinical response to treatment. The exclusion criteria were immunocompromised status or penetrating inoculation.

RESULTS

The A-SCORE demonstrated an area under the receiver operator curve (ROC area) of >86% with regards to all acute complications. It also demonstrated sensitivities >85% and specificities >92% at the cut-off of 4 (Youden index) for all acute complications. The C-SCORE demonstrated an ROC area of 100% with regards to chronic osteomyelitis. It also demonstrated sensitivities >70% and specificities >93% for the chronic morbidity variables seen in our population at the cut-off of 3 (Youden index.).

CONCLUSIONS

These novel composite clinical scores, in combination with clinical judgment, could help guide early care decisions. The A-SCORE and C-SCORE are useful risk stratification tools in the management of pediatric AHO and in predicting acute complicated courses or chronic sequelae of AHO, respectively. These scoring systems, if integrated into standardized pediatric AHO guidelines, can allow clinicians to stratify the AHO population and guide clinical decision making.

LEVEL OF EVIDENCE

Level III (prognostic study, retrospective chart review).

Acute Isolated Irreducible Proximal Interphalangeal Joint Dislocation of the Fifth Toe in a Toddler: A Case Report

A male child aged three years and three months presented after stubbing his right fifth toe. Imaging revealed a dorsolateral dislocation of the proximal interphalangeal joint (PIPJ). After failed attempts at closed reduction, open reduction and internal fixation was pursued. At the one-year follow-up, the patient was found to be doing well clinically and radiographically. These types of injuries require a high degree of clinical suspicion to obtain the proper imaging. The interposition of adjacent soft tissues can render these injuries irreducible. When irreducible, open reduction and pin fixation may be appropriate after an adequate trial of closed reduction under anesthesia. Concomitant ligamentous injuries, avulsion injuries, and fracture-dislocations often accompany these injuries; however, they can also occur in isolation.

Multidisciplinary Management of Infantile Hypophosphatasia Resulting in Radiographic and Clinical Improvement: A Case Report

Hypophosphatasia (HPP) is a rare genetic condition that can manifest from the prenatal period to adulthood. Clinical presentation is characterized by six major forms. HPP can be complex and debilitating. A two-year-old male with a past medical history of HPP presented to our emergency room with a non-displaced supracondylar fracture after minor trauma. Non-accidental trauma was considered in addition to inadequate medical control of his HPP. He was referred to our multidisciplinary clinic and asfotase alfa was increased to an appropriate dose. A multidisciplinary approach is the standard of care for the management of children with HPP, allowing for routine evaluation by tertiary specialists. This includes medication dosing surveillance with serum studies and imaging. Enzyme replacement therapy, appropriately dosed by considering weight and laboratory values, may reduce orthopedic complications. A multidisciplinary team's surveillance of patients with HPP ensures proper medication management, decreases the likelihood of bony injury and encourages continued patient follow-up.

Extreme Genu Recurvatum Deformity in a Pediatric Patient With Spondyloepiphyseal Dysplasia: Gradual Correction With Z-plates and Hexapod Frame

Spondyloepiphyseal dysplasia is a type II collagenopathy with resulting spinal and extremity deformities. The clinical manifestations include short stature, hearing loss, kyphoscoliosis, and complex knee deformities. Genu recurvatum can be a challenging surgical problem, especially when the deformity is severe. In this report, we present a case of severe genu recurvatum in a 14-year-old female that was treated with a pediatric circular fixator with the addition of two z-plates. At one year follow-up, the patient demonstrated improved knee range of motion, tibial alignment with the radiographic union, and good ambulatory ability. The hexapod fixator with the use of two Z-plates may help ensure that appropriate ring strut angles are achieved. Larger studies regarding the efficacy of this treatment option in spondyloepiphyseal dysplasia are required.

Progressive Ankle Subluxation Following Panfibular Osteomyelitis Requiring Fibular Resection

A 10-month-old boy presented with fever, a swollen left leg, and septicemic shock. He was diagnosed with panfibular osteomyelitis. Failure of combined medical and surgical treatment to achieve source control necessitated fibular resection. He subsequently developed a progressive superolateral subluxation of his left ankle, valgus deformity, and brace intolerance. Tibiotalar arthrodesis resulted in a stable plantigrade ankle, excellent weight-bearing ability, and a minor leg-length discrepancy at the 14-month postoperative follow-up.

Shoulder Synovial Chondromatosis in an Adolescent Athlete: A Case Report

Introduction

Synovial chondromatosis refers to a benign proliferative disease of the synovium. Reports in children are rare and reports involving the pediatric shoulder are even more rare. In this review of the literature and case report, we provide a summary of all published cases in children and a report of a case of shoulder synovial chondromatosis in an adolescent female athlete.

Case Presentation

A 15-year-old female cheerleader presented to the clinic with gradual onset right shoulder pain with a severity of 5/10. On physician examination, the patient had tenderness over the proximal humerus, limited abduction to 160°, limited forward flexion, and a total arc of motion of <180°. Radiograph of the shoulder demonstrated multiple calcific intra-articular loose bodies consistent with synovial chondromatosis. Arthroscopic removal resulted in resolution of symptoms at the 36-week follow-up.

Conclusions

Our literature search revealed only eight case reports on shoulder synovial chondromatosis in children. The location of the chondromatosis within the shoulder joint can be intra-articular, extra-articular, within the biceps sheath, or combined. In general, for chondomatoses confined to the glenohumeral joint space, open surgery is not required. Bony erosions can occur in the setting of chondromatosis though may not need to be addressed surgically. Although rare, this diagnosis should be considered when confronted with shoulder pain that is exacerbated during long athletic events with limited range of motion on physical examination in the adolescent athlete. Arthroscopic treatment in conjunction with physical therapy and early mobilization can lead to a successful outcome.

A Comprehensive Review of Viscosupplementation in Osteoarthritis of the Knee

Purpose of Review

The purpose of this systematic review is to discuss emerging evidence in the field of viscosupplementation for chronic knee pain secondary to Osteoarthritis (OA). This review focuses on types of viscosupplementation that are clinically available currently, evidence to support their use, contraindications, and adverse events.

Recent Findings

OA, also known as degenerative joint disease, is the most common form of arthritis in the United States, affecting 54.4 million, or 22.7% of the adult population. The knee is the most common joint affected in OA, with up to 41% involvement, 30% in the hands, and 19% in the hips. The pathophysiology of OA is complex, with contributing factors including mechanical stress to the joint, as well as many person-specific factors such as genetic susceptibility, ethnicity, nutrition, and sex. Treatment modalities include weight control, exercise, non-steroidal and steroidal anti-inflammatory drugs, opioids, intra-articular platelet-rich plasma, placebo, corticosteroid injection, intra-articular viscosupplementation, and surgery. Viscosupplementation consists of injection of hyaluronic acid (HA) into affected joints, intending to restore the physiologic viscoelasticity in the synovial fluid (SF) in the absence of inflammation. HA has also been shown to downregulate pro-inflammatory factors, such as PGE2 and NFkB, and proteases and proteinases known to break down the joint matrix.The contraindications for HA injection are similar to any other injection therapy, and adverse events are usually mild, local, and transient. Viscosupplementation (VS) is effective over placebo and more effective than NSAIDs and corticosteroids in pain reduction and improved functionality; however, guidelines recommend neither for nor against its use, demonstrating variability in the existing evidence base.Current VS options divide primarily into native vs. cross-linked and low-molecular-weight vs. high-molecular-weight. Current treatment options include Hylan g-f-20, Sodium Hyaluronate preparations (Suparts Fx, Euflexxa, Gelsyn-3, Durolane, Hyalgen), single-use agents (Gel-One, Synvisc-One, Monovisc), and Hyaluronan (Orthovisc, Monovisc, Hymovic). They share a common safety profile, and all have evidence supporting their efficacy. Their specific details are reviewed here.

Summary

OA is the most common form of arthritis. It is a chronic, debilitating illness with a high impact on the functionality and quality of life of a significant part of the population in the western world. Treatments include medical management, physical therapy, activity modification, injection, and surgery. VS effectively reduces pain, increases functionality, and delays surgery in the knee to treat osteoarthritis. While previous studies have demonstrated variable results, more evidence is becoming available generally supportive of the benefit of VS in the treatment of knee OA.

Primary Bacterial Pyomyositis in Children: A Systematic Review

BACKGROUND

Tropical pyomyositis has had a recent increase in the United States, Europe, and other nontropical areas. The purpose of this study was to provide an accurate description of the demographics, presenting features, sites of involvement, microbiology, imaging modalities, medical and surgical management, complications, and predictors of clinical course.

METHODS

We searched PubMed, Cochrane, Web of Science Collection, Scopus, and Embase databases yielding 156 studies. Of these, 23 articles were selected for statistical analysis.

RESULTS

The average age at presentation was 8.4±1.9 years with males more commonly affected. Fever, painful limp, and localized pain were the most common presenting symptoms. Pelvis, lower extremity, trunk and spine, in descending order, were the most commonly affected locations. Iliopsoas, obturator musculature, and gluteus musculature were the most commonly affected muscle groups. The mean time to diagnosis was 6.6±3.05 days. Staphylococcus aureus was the most common offending organism. The mean length of hospital stay was 12.0±4.6 days. Medical management alone was successful in 40% of cases (143/361) with an average duration of 9.5±4.0 and 22.7±7.2 days of intravenous and oral antibiotics, respectively. Surgical management consisted of open drainage in 91.3% (199/218) or percutaneous drainage in 8.7% (19/218) of cases. Painful limp, fever, and larger values of white cell count and erythrocyte sedimentation rate were associated with an increased need for surgery. Obturator and calf muscle involvement were strongly associated with multifocal involvement. There were 42 complications in 41 patients (11.3%). Methicillin-resistant S. aureus was associated with an increased risk of complications. The most common complications were osteomyelitis, septicemia, and septic arthritis.

CONCLUSIONS

Primary pyomyositis should be considered in cases suggesting pediatric infection. Magnetic resonance imaging is the most commonly used imaging modality; however, ultrasound is useful given its accessibility and low cost. Medical management alone can be successful, but surgical treatment is often needed. The prognosis is favorable. Early diagnosis, appropriate medical management, and potential surgical drainage are required for effective treatment.

LEVEL OF EVIDENCE

Level IV-systematic review.

Tension-Sided Femoral Neck Stress Fracture in an Adolescent with Vitamin D Deficiency and Osteomalacia: A Case Report

CASE

An adolescent girl presented with groin pain without any history of trauma. Imaging showed a tension-sided stress fracture of the femoral neck. Vitamin D deficiency (VDD), and raised alkaline phosphatase and parathyroid hormone levels were found. Pain relief was not achieved with nonoperative treatment. Considering the risk of fracture progression and displacement, the fracture was fixed with cannulated cancellous screws. Fracture healed without any complications.

CONCLUSION

A tension-sided femoral neck stress fracture, with VDD and osteomalacia, is a rare cause of hip pain in an adolescent. Surgical fracture stabilization is necessary in addition to medical treatment.

Diversity and Inclusion in an Orthopaedic Surgical Society: A Longitudinal Study

BACKGROUND

Diversity and inclusion are critical to providing the best possible health care. Previous studies have shown that diversity among physicians increases cultural competency, which in turn enhances the quality of care provided and increases minoritized patients' participation in decisions regarding their health care. However, physician diversity in both race and sex is lacking in orthopaedic surgery. This study seeks to determine the sex and racial diversity in the membership and leadership of the Pediatric Orthopaedic Society of North America (POSNA).

METHODS

POSNA membership and leadership were reviewed for the years 2010, 2015, and 2020. This data was gathered from membership directories and committee reference books. All North American Active Members' race/ethnicity and sex were recorded for each year. The categories for race/ethnicity are Caucasian, East/South/Middle Eastern Asian American (Asian), Hispanic/Latin/South American (HLSA), and African American.

RESULTS

From 2010 to 2020, Active Members of POSNA increased from 608 to 818, and the percentage of female (14.6% to 23.7%), Asian (7.4% to 11.2%), HLSA (2.5% to 2.9%), and African American membership (1.6% to 1.8%) increased. Male (85.4% to 76.3%) and Caucasian (88.5% to 84.0%) membership decreased. From 2010 to 2020, male leadership decreased on both the Board of Directors and Committee Chairs (89.5% to 81.8% and 86.4% to 64.7%, respectively), as did Caucasians (94.7% to 81.8% and 90.9% to 88.2%, respectively). The number of Asian members holding positions on both the Board of Directors and Committee Chairs increased (0% to 18.2% and 4.5% to 11.8%, respectively) as did the number of females (10.5% to 18.2% and 13.6% to 35.3%, respectively). HLSA and African American members were proportionally represented in leadership for the years 2010 and 2015.

CONCLUSIONS

Membership in POSNA has increased between 2010 to 2020 for every diversity category examined and POSNA membership exhibits significantly more diversity than the orthopaedic specialty as a whole. Leadership as a whole is more diverse in 2020 than it was in 2010.

LEVEL OF EVIDENCE

Level II-retrospective.

Etiology Diagnosis and Management of Radial Nerve Entrapment

Context

The anatomy of the radial nerve is prone to entrapment, each with different symptomology. Compression of entrapment of the radial nerve can occur near the radiocapitellar joint, the spiral groove, the arcade of Frohse, the tendon of the extensor carpi radialis brevis (ECRB), and at the radial tunnel. Those who require repetitive motions are at increased risk of peripheral neuropathy syndromes, including repetitive pronation and supination, trauma, or systemic disease; however, t the influence of all risk factors is not well understood. Depending on the location of entrapment, radial nerve entrapment syndrome presents different symptoms. It may include both a motor component and a sensory component. The motor component includes a dropped arm, and the sensory component can include pain and paresthesia in the distribution of the radial nerve that resolves with rest and exacerbates by repetitive pronation and supination.

Evidence Acquisition

Diagnostic evaluation for radial nerve entrapment, apart from clinical symptoms and physical exam, includes electromyography, nerve conduction studies, ultrasonography, and magnetic resonance imaging. Conservative management for radial nerve entrapment includes oral anti-inflammatory medications, activity modification, and splinting. Some recently performed studies mentioned promising minimally invasive techniques, including corticosteroid injections, peripheral nerve stimulation, and pulsed radiofrequency.

Results

When minimally invasive techniques fail, open or endoscopic surgery can be performed to release the nerve

Conclusions

Endoscopic surgery has the benefit of decreasing incision size and reducing time to functional recovery.

Prognosis-Based Early Intervention Strategies to Resolve Exacerbation and Progressive Lung Function Decline in Cystic Fibrosis

Cystic fibrosis (CF) is a genetic disease caused by a mutation(s) in the CF transmembrane regulator (CFTR), where progressive decline in lung function due to recurring exacerbations is a major cause of mortality. The initiation of chronic obstructive lung disease in CF involves inflammation and exacerbations, leading to mucus obstruction and lung function decline. Even though clinical management of CF lung disease has prolonged survival, exacerbation and age-related lung function decline remain a challenge for controlling the progressive lung disease. The key to the resolution of progressive lung disease is prognosis-based early therapeutic intervention; thus, the development of novel diagnostics and prognostic biomarkers for predicting exacerbation and lung function decline will allow optimal management of the lung disease. Hence, the development of real-time lung function diagnostics such as forced oscillation technique (FOT), impulse oscillometry system (IOS), and electrical impedance tomography (EIT), and novel prognosis-based intervention strategies for controlling the progression of chronic obstructive lung disease will fulfill a significant unmet need for CF patients. Early detection of CF lung inflammation and exacerbations with the timely resolution will not only prolong survival and reduce mortality but also improve quality of life while reducing significant health care costs due to recurring hospitalizations.

Surgical and Non-surgical Treatment Options for Piriformis Syndrome: A Literature Review

Context

Piriformis syndrome is a solely clinical diagnosis that often eludes the practitioner and goes underdiagnosed. PS is a pain syndrome and for those it affects, causes persistent pain and limits daily activity and work capacity. It is a form of deep gluteal syndrome that needs to be considered on the differential of low back pain as it comprises between 0.3% - 6% of all low back pain cases and is frequently underdiagnosed. Piriformis syndrome may be primary due anatomic anomalies or secondary, though the majority of cases are secondary to some insult. The objective of this manuscript is to provide a description of the epidemiology and presentation of piriformis as well as both non-operative and operative treatment options. We review all of the recent clinical evidence regarding the aforementioned therapies.

Evidence Acquisition

Literature searches were performed using the below MeSH Terms using Mendeley version 1.19.4. Search fields were varied until further searches revealed no new articles. All articles were screened by title and abstract. Decision was made to include an article based on its relevance and the list of final articles was approved three of the authors. This included reading the entirety of the article. Any question regarding the inclusion of an article was discussed by all authors until an agreement was reached.

Results

Medical management and physical therapy show some promise; however, when conservative treatment fails minimally invasive methods such as steroid injections, botulinum toxin injections, dry needling are all efficacious and there is substantial clinical evidence regarding these therapies. In those patients in which minimally invasive techniques do not result in an adequate relief of pain and return of function, endoscopic release can be considered. Endoscopic release is far superior to open release of the piriformis syndrome given the higher success and lower rate of complications.

Conclusions

Piriformis syndrome is an important differential diagnosis in the work up of lower back pain and should not be ruled out with proper examination and testing. Clinicians should consider medical management and conservative management in the initial treatment plan for piriformis syndrome. There are many options within the conservative management and the literature shows much promise regarding these. Physical therapy, steroid injections, botulinum toxin injections, and dry needling are all potentially effective therapies with few adverse effects. Surgical options remain as gold standard, but only when conservative management has failed and the symptoms are significant to affect daily living activities. Endoscopic decompression of the sciatic nerve with or without release of the piriformis muscle has a reported high likelihood of success and a low complication rate. Current literature supports the preference of the endoscopic approach over the open approach due to improved outcomes and decreased complications. Further research is to well define the metrics for the diagnosis of piriformis syndrome and may include a need to develop diagnostic criteria.

Synthesis and Evaluation of Dendrimers for Autophagy Augmentation and Alleviation of Obstructive Lung Diseases

Preservation of cellular homeostasis requires constant synthesis of fresh proteins and cellular organelles and efficient degradation or removal of damaged proteins and cellular components. This involves two cellular degradation processes or molecular mechanisms: the ubiquitin-proteasome and autophagy-lysosomal systems. Impairment of these catabolic processes has been linked to pathogenesis of a variety of chronic obstructive lung diseases such as COPD (chronic obstructive pulmonary disease) and CF (cystic fibrosis). Proteosomal and autophagic functions (proteostasis) are known to decline with advancing age leading to accumulation of cellular debris and proteins, initiating cellular senescence or death and accelerating lung aging. Obstructive lung diseases associated with airway hyperinflammation and mucus obstruction provide major challenges to the delivery and therapeutic efficacy of nanotherapeutics systems as they need to bypass the airway defense. Targeted autophagy augmentation has emerged, as a promising therapeutic utility for alleviating obstructive lung diseases, and promoting healthy aging. A targeted dendrimer-based approach has been designed to penetrate the airway obstruction and allow the selective correction of proteostasis/autophagy in the diseased cells while circumventing the side effects. This report describes methods for synthesis and therapeutic evaluation of autophagy augmenting dendrimers in the treatment of obstructive lung disease(s). The formulations and methods of autophagy augmentation described here are currently under clinical development in our laboratory for alleviating pathogenesis and progression of chronic obstructive lung diseases, and promoting healthy aging.

An Update on Treatment Modalities for Ulnar Nerve Entrapment: A Literature Review

CONTEXT

Ulnar nerve entrapment is a relatively common entrapment syndrome second only in prevalence to carpal tunnel syndrome. The potential anatomic locations for entrapment include the brachial plexus, cubital tunnel, and Guyon's canal. Ulnar nerve entrapment is more so prevalent in pregnancy, diabetes, rheumatoid arthritis, and patients with occupations involving periods of prolonged elbow flexion and/or wrist dorsiflexion. Cyclists are particularly at risk of Guyon's canal neuropathy. Patients typically present with sensory deficits of the palmar aspect of the fourth and fifth digits, followed by motor symptoms, including decreased pinch strength and difficulty fastening shirt buttons or opening bottles.

EVIDENCE ACQUISITION

Literature searches were performed using the below MeSH Terms using Mendeley version 1.19.4. Search fields were varied until further searches revealed no new articles. All articles were screened by title and abstract. Decision was made to include an article based on its relevance and the list of final articles was approved three of the authors. This included reading the entirety of the artice. Any question regarding the inclusion of an article was discussed by all authors until an agreement was reached.

RESULTS

X-ray and CT play a role in diagnosis when a bony injury is thought to be related to the pathogenesis (i.e., fracture of the hook of the hamate.) MRI plays a role where soft tissue is thought to be related to the pathogenesis (i.e., tumor or swelling.) Electromyography and nerve conduction also play a role in diagnosis. Medical management, in conjunction with physical therapy, shows limited promise. However, minimally invasive techniques, including peripheral percutaneous electrode placement and ultrasound-guided electrode placement, have all been recently studied and show great promise. When these techniques fail, clinicians should resort to decompression, which can be done endoscopically or through an open incision. Endoscopic ulnar decompression shows great promise as a surgical option with minimal incisions.

CONCLUSIONS

Clinical diagnosis of ulnar nerve entrapment can often be delayed and requires the suspicion as well as a thorough neurological exam. Early recognition and diagnois are important for early institution of treatment. A wide array of diagnostic imaging can be useful in ruling out bony, soft tissue, or vascular etiologies, respectively. However, clinicians should resort to electrodiagnostic testing when a definitive diagnois is needed. Many new minimally invasive techniques are in the literature and show great promise; however, further large scale trials are needed to validate these techniques. Surgical options remains as a gold standard when adequate symptom relief is not achieved through minimally invasive means.

Autophagy Augmentation to Alleviate Immune Response Dysfunction, and Resolve Respiratory and COVID-19 Exacerbations

The preservation of cellular homeostasis requires the synthesis of new proteins (proteostasis) and organelles, and the effective removal of misfolded or impaired proteins and cellular debris. This cellular homeostasis involves two key proteostasis mechanisms, the ubiquitin proteasome system and the autophagy–lysosome pathway. These catabolic pathways have been known to be involved in respiratory exacerbations and the pathogenesis of various lung diseases, such as chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), idiopathic pulmonary fibrosis (IPF), acute lung injury (ALI), acute respiratory distress syndrome (ARDS), and coronavirus disease-2019 (COVID-19). Briefly, proteostasis and autophagy processes are known to decline over time with age, cigarette or biomass smoke exposure, and/or influenced by underlying genetic factors, resulting in the accumulation of misfolded proteins and cellular debris, elevating apoptosis and cellular senescence, and initiating the pathogenesis of acute or chronic lung disease. Moreover, autophagic dysfunction results in an impaired microbial clearance, post-bacterial and/or viral infection(s) which contribute to the initiation of acute and recurrent respiratory exacerbations as well as the progression of chronic obstructive and restrictive lung diseases. In addition, the autophagic dysfunction-mediated cystic fibrosis transmembrane conductance regulator (CFTR) immune response impairment further exacerbates the lung disease. Recent studies demonstrate the therapeutic potential of novel autophagy augmentation strategies, in alleviating the pathogenesis of chronic obstructive or restrictive lung diseases and exacerbations such as those commonly seen in COPD, CF, ALI/ARDS and COVID-19.

Use of spinal cord stimulation for the treatment of post total knee arthroplasty pain

Total knee arthroplasty (TKA), a common elective surgical procedure, is indicated in patients with knee pain that becomes refractory to nonsurgical interventions, such as weight loss, physical activity, physical therapy, and pharmacologic treatment. However, postoperative chronic pain is frequently reported and may lead to opioid use and dependence. Due to the increasing concern of the overuse of opioids in medical treatments, a search for other viable options is recognized. As a consequence, alternative therapies, such as transcutaneous electrical nerve stimulation (TENS), pulsed radiofrequency (PRF), and spinal cord stimulation (SCS) are being tried to potentially replace traditional opioid use in treating persistent postsurgical pain (PPSP), thus reducing opioid dependence across the nation. Here, we provide a brief overview of persistent pain following TKA procedures, with a particular emphasis on the role of promising therapies, such as TENS, PRF, and SCS for the treatment of post-TKA pain.

Novel cystamine-core dendrimer-formulation rescues ΔF508-CFTR and inhibits Pseudomonas aeruginosa infection by augmenting autophagy

BACKGROUND

Cystic fibrosis (CF) is challenged with pathophysiological barriers for effective airway drug-delivery. Hence, we standardized the therapeutic efficacy of the novel dendrimer-based autophagy-inducing anti-oxidant drug, cysteamine.

RESEARCH DESIGN AND METHODS

Human primary-CF epithelial-cells, CFBE41o-cells were used to standardize the efficacy of the dendrimer-cystamine in correcting impaired-autophagy, rescuing ΔF508-CFTR and Pseudomonas-aeruginosa (Pa) infection.

RESULTS

We first designed a novel cystamine-core dendrimer formulation (G4-CYS) that significantly increases membrane-ΔF508CFTR expression in CFBE41o-cells (p < 0.05) by forming its reduced-form cysteamine, in vivo. Additionally, G4-CYS treatment corrects ΔF508-CFTR-mediated impaired-autophagy as observed by a significant decrease (p < 0.05) in Ub-LC3-positive aggresome-bodies. Next, we verified that in non-permeabilized CFBE41o-cells, G4-CYS significantly (p < 0.05) induces ΔF508-CFTR's forward-trafficking to the plasma membrane. Furthermore, cysteamine's known antibacterial and anti-biofilm properties against Pa were enhanced as our findings demonstrate that both G4-CYS and its control DAB-core dendrimer, G4-DAB, exhibited significant (p < 0.05) bactericidal-activity against Pa. We also found that both G4-CYS and G4-DAB exhibit marked mucolytic-activity against porcine-mucus (p < 0.05). Finally, we demonstrate that G4-CYS not only corrects the autophagy-impairment by rescuing ΔF508-CFTR in CFBE41o-cells but also corrects the intrinsic phagocytosis defect (p < 0.05).

CONCLUSIONS

Overall, our data demonstrates the efficacy of novel cystamine-dendrimer formulation in rescuing ΔF508-CFTR to the plasma membrane and inhibiting Pa bacterial-infection by augmenting autophagy.

Adapting Proteostasis and Autophagy for Controlling the Pathogenesis of Cystic Fibrosis Lung Disease

Cystic fibrosis (CF), a fatal genetic disorder predominant in the Caucasian population, is caused by mutations in the cystic fibrosis transmembrane conductance regulator (Cftr) gene. The most common mutation is the deletion of phenylalanine from the position-508 (F508del-CFTR), resulting in a misfolded-CFTR protein, which is unable to fold, traffic and retain its plasma membrane (PM) localization. The resulting CFTR dysfunction, dysregulates variety of key cellular mechanisms such as chloride ion transport, airway surface liquid (ASL) homeostasis, mucociliary-clearance, inflammatory-oxidative signaling, and proteostasis that includes ubiquitin-proteasome system (UPS) and autophagy. A collective dysregulation of these key homoeostatic mechanisms contributes to the development of chronic obstructive cystic fibrosis lung disease, instead of the classical belief focused exclusively on ion-transport defect. Hence, therapeutic intervention(s) aimed at rescuing chronic CF lung disease needs to correct underlying defect that mediates homeostatic dysfunctions and not just chloride ion transport. Since targeting all the myriad defects individually could be quite challenging, it will be prudent to identify a process which controls almost all disease-promoting processes in the CF airways including underlying CFTR dysfunction. There is emerging experimental and clinical evidence that supports the notion that impaired cellular proteostasis and autophagy plays a central role in regulating pathogenesis of chronic CF lung disease. Thus, correcting the underlying proteostasis and autophagy defect in controlling CF pulmonary disease, primarily via correcting the protein processing defect of F508del-CFTR protein has emerged as a novel intervention strategy. Hence, we discuss here both the rationale and significant therapeutic utility of emerging proteostasis and autophagy modulating drugs/compounds in controlling chronic CF lung disease, where targeted delivery is a critical factor-influencing efficacy.

Autophagy augmentation alleviates cigarette smoke-induced CFTR-dysfunction, ceramide-accumulation and COPD-emphysema pathogenesis

In this study, we aimed to investigate precise mechanism(s) of sphingolipid-imbalance and resulting ceramide-accumulation in COPD-emphysema. Where, human and murine emphysema lung tissues or human bronchial epithelial cells (Beas2b) were used for experimental analysis. We found that lungs of smokers and COPD-subjects with increasing emphysema severity demonstrate sphingolipid-imbalance, resulting in significant ceramide-accumulation and increased ceramide/sphingosine ratio, as compared to non-emphysema/non-smoker controls. Next, we found a substantial increase in emphysema chronicity-related ceramide-accumulation in murine (C57BL/6) lungs, while sphingosine levels only slightly increased. In accordance, the expression of the acid ceramidase decreased after CS-exposure. Moreover, CS-induced (sub-chronic) ceramide-accumulation was significantly (p < 0.05) reduced by treatment with TFEB/autophagy-inducing drug, gemfibrozil (GEM), suggesting that autophagy regulates CS-induced ceramide-accumulation. Next, we validated experimentally that autophagy/lipophagy-induction using an anti-oxidant, cysteamine, significantly (p < 0.05) reduces CS-extract (CSE)-mediated intracellular-ceramide-accumulation in p62 + aggresome-bodies. In addition to intracellular-accumulation, we found that CSE also induces membrane-ceramide-accumulation by ROS-dependent acid-sphingomyelinase (ASM) activation and plasma-membrane translocation, which was significantly controlled (p < 0.05) by cysteamine (an anti-oxidant) and amitriptyline (AMT, an inhibitor of ASM). Cysteamine-mediated and CSE-induced membrane-ceramide regulation was nullified by CFTR-inhibitor-172, demonstrating that CFTR controls redox impaired-autophagy dependent membrane-ceramide accumulation. In summary, our data shows that CS-mediated autophagy/lipophagy-dysfunction results in intracellular-ceramide-accumulation, while acquired CFTR-dysfunction-induced ASM causes membrane ceramide-accumulation. Thus, CS-exposure alters the sphingolipid-rheostat leading to the increased membrane- and intracellular- ceramide-accumulation inducing COPD-emphysema pathogenesis that is alleviated by treatment with cysteamine, a potent anti-oxidant with CFTR/autophagy-augmenting properties.

Inhibition of histone-deacetylase activity rescues inflammatory cystic fibrosis lung disease by modulating innate and adaptive immune responses

Background

Chronic lung disease resulting from dysfunctional cystic fibrosis transmembrane conductance regulator (CFTR) and NFκB-mediated neutrophilic-inflammation forms the basis of CF-related mortality. Here we aimed to evaluate if HDAC inhibition controls Pseudomonas-aeruginosa-lipopolysaccharide (Pa-LPS) induced airway inflammation and CF-lung disease.

Methods

For in vitro experiments, HEK293-cells were transfected with IL-8 or NFκB-firefly luciferase, and SV40-renilla- luciferase reporter constructs or ΔF508-CFTR-pCEP, followed by treatment with suberoylanilide hydroxamic acid (SAHA), Trichostatin-A (TSA) and/or TNFα. For murine studies, Cftr^+/+ or Cftr^−/− mice (n = 3) were injected/instilled with Pa-LPS and/or treated with SAHA or vehicle control. The progression of lung disease was monitored by quantifying changes in inflammatory markers (NFκB), cytokines (IL-6/IL-10), neutrophil activity (MPO, myeloperoxidase and/or NIMP-R14) and T-reg numbers.

Results

SAHA treatment significantly (p < 0.05) suppresses TNFα-induced NFκB and IL-8 reporter activities in HEK293-cells. Moreover, SAHA, Tubacin (selective HDAC6-inhibitor) or HDAC6-shRNAs controls CSE-induced ER-stress activities (p < 0.05). In addition, SAHA restores trafficking of misfolded-ΔF508-CFTR, by inducing protein levels of both B and C forms of CFTR. Murine studies using Cftr^+/+ or Cftr^−/− mice verified that SAHA controls Pa-LPS induced IL-6 levels, and neutrophil (MPO levels and/or NIMP-R14), NFκB-(inflammation) and Nrf2 (oxidative-stress marker) activities, while promoting FoxP3⁺ T-reg activity.

Conclusion

In summary, SAHA-mediated HDAC inhibition modulates innate and adaptive immune responses involved in pathogenesis and progression of inflammatory CF-lung disease.

Electronic supplementary material

The online version of this article (10.1186/s12931-017-0705-8) contains supplementary material, which is available to authorized users.

Cigarette Smoke Exposure Inhibits Bacterial Killing via TFEB-Mediated Autophagy Impairment and Resulting Phagocytosis Defect

INTRODUCTION

Cigarette smoke (CS) exposure is the leading risk factor for COPD-emphysema pathogenesis. A common characteristic of COPD is impaired phagocytosis that causes frequent exacerbations in patients leading to increased morbidity. However, the underlying mechanism is unclear. Hence, we investigated if CS exposure causes autophagy impairment as a mechanism for diminished bacterial clearance via phagocytosis by utilizing murine macrophages (RAW264.7 cells) and Pseudomonas aeruginosa (PA01-GFP) as an experimental model.

METHODS

Briefly, RAW cells were treated with cigarette smoke extract (CSE), chloroquine (autophagy inhibitor), TFEB-shRNA, CFTR(inh)-172, and/or fisetin prior to bacterial infection for functional analysis.

RESULTS

Bacterial clearance of PA01-GFP was significantly impaired while its survival was promoted by CSE (p < 0.01), autophagy inhibition (p < 0.05; p < 0.01), TFEB knockdown (p < 0.01; p < 0.001), and inhibition of CFTR function (p < 0.001; p < 0.01) in comparison to the control group(s) that was significantly recovered by autophagy-inducing antioxidant drug, fisetin, treatment (p < 0.05; p < 0.01; and p < 0.001). Moreover, investigations into other pharmacological properties of fisetin show that it has significant mucolytic and bactericidal activities (p < 0.01; p < 0.001), which warrants further investigation.

CONCLUSIONS

Our data suggests that CS-mediated autophagy impairment as a critical mechanism involved in the resulting phagocytic defect, as well as the therapeutic potential of autophagy-inducing drugs in restoring is CS-impaired phagocytosis.

Dendrimer-based selective autophagy-induction rescues ΔF508-CFTR and inhibits Pseudomonas aeruginosa infection in cystic fibrosis

Background

Cystic Fibrosis (CF) is a genetic disorder caused by mutation(s) in the CF-transmembrane conductance regulator (Cftr) gene. The most common mutation, ΔF508, leads to accumulation of defective-CFTR protein in aggresome-bodies. Additionally, Pseudomonas aeruginosa (Pa), a common CF pathogen, exacerbates obstructive CF lung pathology. In the present study, we aimed to develop and test a novel strategy to improve the bioavailability and potentially achieve targeted drug delivery of cysteamine, a potent autophagy-inducing drug with anti-bacterial properties, by developing a dendrimer (PAMAM-DEN)-based cysteamine analogue.

Results

We first evaluated the effect of dendrimer-based cysteamine analogue (PAMAM-DEN^CYS) on the intrinsic autophagy response in IB3-1 cells and observed a significant reduction in Ub-RFP and LC3-GFP co-localization (aggresome-bodies) by PAMAM-DEN^CYS treatment as compared to plain dendrimer (PAMAM-DEN) control. Next, we observed that PAMAM-DEN^CYS treatment shows a modest rescue of ΔF508-CFTR as the C-form. Moreover, immunofluorescence microscopy of HEK-293 cells transfected with ΔF508-CFTR-GFP showed that PAMAM-DEN^CYS is able to rescue the misfolded-ΔF508-CFTR from aggresome-bodies by inducing its trafficking to the plasma membrane. We further verified these results by flow cytometry and observed significant (p<0.05; PAMAM-DEN vs. PAMAM-DEN^CYS) rescue of membrane-ΔF508-CFTR with PAMAM-DEN^CYS treatment using non-permeabilized IB3-1 cells immunostained for CFTR. Finally, we assessed the autophagy-mediated bacterial clearance potential of PAMAM-DEN^CYS by treating IB3-1 cells infected with PA01-GFP, and observed a significant (p<0.01; PAMAM-DEN vs. PAMAM-DEN^CYS) decrease in intracellular bacterial counts by immunofluorescence microscopy and flow cytometry. Also, PAMAM-DEN^CYS treatment significantly inhibits the growth of PA01-GFP bacteria and demonstrates potent mucolytic properties.

Conclusions

We demonstrate here the efficacy of dendrimer-based autophagy-induction in preventing sequestration of ΔF508-CFTR to aggresome-bodies while promoting its trafficking to the plasma membrane. Moreover, PAMAM-DEN^CYS decreases Pa infection and growth, while showing mucolytic properties, suggesting its potential in rescuing Pa-induced ΔF508-CF lung disease that warrants further investigation in CF murine model.

Augmentation of S-Nitrosoglutathione Controls Cigarette Smoke-Induced Inflammatory-Oxidative Stress and Chronic Obstructive Pulmonary Disease-Emphysema Pathogenesis by Restoring Cystic Fibrosis Transmembrane Conductance Regulator Function

AIMS

Cigarette smoke (CS)-mediated acquired cystic fibrosis transmembrane conductance regulator (CFTR)-dysfunction, autophagy-impairment, and resulting inflammatory-oxidative/nitrosative stress leads to chronic obstructive pulmonary disease (COPD)-emphysema pathogenesis. Moreover, nitric oxide (NO) signaling regulates lung function decline, and low serum NO levels that correlates with COPD severity. Hence, we aim to evaluate here the effects and mechanism(s) of S-nitrosoglutathione (GSNO) augmentation in regulating inflammatory-oxidative stress and COPD-emphysema pathogenesis.

RESULTS

Our data shows that cystic fibrosis transmembrane conductance regulator (CFTR) colocalizes with aggresome bodies in the lungs of COPD subjects with increasing emphysema severity (Global Initiative for Chronic Obstructive Lung Disease [GOLD] I - IV) compared to nonemphysema controls (GOLD 0). We further demonstrate that treatment with GSNO or S-nitrosoglutathione reductase (GSNOR)-inhibitor (N6022) significantly inhibits cigarette smoke extract (CSE; 5%)-induced decrease in membrane CFTR expression by rescuing it from ubiquitin (Ub)-positive aggresome bodies (p < 0.05). Moreover, GSNO restoration significantly (p < 0.05) decreases CSE-induced reactive oxygen species (ROS) activation and autophagy impairment (decreased accumulation of ubiquitinated proteins in the insoluble protein fractions and restoration of autophagy flux). In addition, GSNO augmentation inhibits protein misfolding as CSE-induced colocalization of ubiquitinated proteins and LC3B (in autophagy bodies) is significantly reduced by GSNO/N6022 treatment. We verified using the preclinical COPD-emphysema murine model that chronic CS (Ch-CS)-induced inflammation (interleukin [IL]-6/IL-1β levels), aggresome formation (perinuclear coexpression/colocalization of ubiquitinated proteins [Ub] and p62 [impaired autophagy marker], and CFTR), oxidative/nitrosative stress (p-Nrf2, inducible nitric oxide synthase [iNOS], and 3-nitrotyrosine expression), apoptosis (caspase-3/7 activity), and alveolar airspace enlargement (Lm) are significantly (p < 0.05) alleviated by augmenting airway GSNO levels. As a proof of concept, we demonstrate that GSNO augmentation suppresses Ch-CS-induced perinuclear CFTR protein accumulation (p < 0.05), which restores both acquired CFTR dysfunction and autophagy impairment, seen in COPD-emphysema subjects.

INNOVATION

GSNO augmentation alleviates CS-induced acquired CFTR dysfunction and resulting autophagy impairment.

CONCLUSION

Overall, we found that augmenting GSNO levels controls COPD-emphysema pathogenesis by reducing CS-induced acquired CFTR dysfunction and resulting autophagy impairment and chronic inflammatory-oxidative stress. Antioxid. Redox Signal. 27, 433-451.

Cigarette smoke induced autophagy-impairment regulates AMD pathogenesis mechanisms in ARPE-19 cells

Age related macular degeneration (AMD) is one of the leading causes of blindness. Genetics, environmental insult, and age-related factors all play a key role in altering proteostasis, the homeostatic process regulating protein synthesis, degradation and processing. These factors also play a role in the pathogenesis of AMD and it has been well established that cigarette smoking (CS) initiates AMD pathogenic mechanisms. The primary goal of this study is to elucidate whether CS can induce proteostasis/autophagy-impairment in retinal pigment epithelial (RPE) cells. In our preliminary analysis, it was found that cigarette smoke extract (CSE) induces accumulation of ubiquitinated proteins in the insoluble protein fraction (p < 0.01), which was subsequently mitigated through cysteamine (p < 0.01) or fisetin (p < 0.05) treatment. Further, it was verified that these CSE induced ubiquitinated proteins accumulated in the peri-nuclear spaces (p<0.05) that were cleared- off with cysteamine (p < 0.05) or fisetin (p < 0.05). Moreover, CSE-induced aggresome-formation (LC3B-GFP and Ub-RFP co-localization) and autophagy-flux impairment was significantly (p<0.01) mitigated by cysteamine (p<0.05) or fisetin (p<0.05) treatment, indicating the restoration of CSE-mediated autophagy-impairment. CSE treatment was also found to induce intracellular reactive oxygen species (ROS, p < 0.001) while impacting cell viability (p < 0.001), which was quantified using CMH2DCFDA-dye (ROS) and MTS (proliferation) or propodium iodide staining (cell viability) assays, respectively. Moreover, cysteamine and fisetin treatment ameliorated CS-mediated ROS production (p < 0.05) and diminished cell viability (p < 0.05). Lastly, CSE was found to induce cellular senescence (p < 0.001), which was significantly ameliorated by cysteamine (p < 0.001) or fisetin (p < 0.001). In conclusion, our study indicates that CS induced proteostasis/autophagy-impairment regulates mechanisms associated with AMD pathogenesis. Moreover, autophagy-inducing drugs such as cysteamine or fisetin can ameliorate AMD pathogenesis mechanisms that warrant further investigation in pre-clinical murine models.