First Measurement of the |t| Dependence of Incoherent J/ψ Photonuclear Production

The first measurement of the cross section for incoherent photonuclear production of J/ψ vector mesons as a function of the Mandelstam |t| variable is presented. The measurement was carried out with the ALICE detector at midrapidity, |y|<0.8, using ultraperipheral collisions of Pb nuclei at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.02  TeV. This rapidity interval corresponds to a Bjorken-x range (0.3-1.4)×10^{-3}. Cross sections are given in five |t| intervals in the range 0.04<|t|<1  GeV^{2} and compared to the predictions by different models. Models that ignore quantum fluctuations of the gluon density in the colliding hadron predict a |t| dependence of the cross section much steeper than in data. The inclusion of such fluctuations in the same models provides a better description of the data.

The prognostic and predictive role of class III β-Tubulin and hENT1 expression in patients with advanced pancreatic ductal adenocarcinoma

BACKGROUND

FOLFIRINOX and gemcitabine-nabpaclitaxel (GnP) are standard first-line treatment regimens for advanced pancreatic ductal adenocarcinoma (PDAC). However, currently, there is a lack of predictive biomarkers to aid in the treatment selection. We aimed to explore the prognostic and predictive value of class III β-Tubulin (TUBB3) and human equilibrative nucleoside transporter 1 (hENT1) expression, which have previously been shown to be associated with taxane and gemcitabine resistance in advanced PDAC.

METHODS

We conducted a retrospective analysis of 106 patients with advanced PDAC treated with GnP and/or FOLFIRINOX at our institution. TUBB3 and hENT1 immunohistochemical staining was performed on tumor specimens and subsequently evaluated based on the intensity and percentage of expression.

RESULTS

In patients who received the GnP regimen, a high combined score (TUBB3low/hENT1high) was associated with a higher DCR and longer PFS compared to those with intermediate (TUBB3high/hENT1high or TUBB3low/hENT1low) and low score (TUBB3high/hENT1low). In the multivariate analysis, a high combined score was an independent predictor of higher DCR (OR:11.96; 95 % CI:2.61-54.82; p = 0.001) and longer PFS (HR:0.33; 95%CI:0.18-0.60; p < 0.001). However, there was no difference in response rates or PFS based on TUBB3 and hENT1 expression among patients receiving the FOLFIRINOX regimen.

CONCLUSION

Our findings indicate that tumor TUBB3 and hENT1 expression may predict the efficacy of the GnP regimen, and low TUBB3 and high hENT1 expression (TUBB3low/hENT1high) are associated with a higher DCR and longer PFS in patients treated with GnP. Evaluating TUBB3 and hENT1 jointly can identify the patients most (as well as least) likely to benefit from GnP chemotherapy.

Evaluation of Differences in Patellar Height After Patellar Stabilization Procedures Not Intended to Address Patella Alta: A Multicenter Study

Background

Recent studies have reported conflicting results as to whether isolated medial patellofemoral ligament reconstruction (MPFLr) leads to decreased patellar height.

Purpose

To investigate if patellar stabilization surgery not intended to address patella alta influences patellar height.

Study Design

Cohort study; Level of evidence, 3.

Methods

A multicenter retrospective chart review was conducted, and patients who underwent MPFLr, medializing tibial tuberosity osteotomy (TTO), and/or trochleoplasty between 2016 and 2020 were included. The Caton-Deschamps index (CDI) was calculated from radiographs obtained preoperatively, 2 weeks postoperatively, and 3 months postoperatively. The preoperative CDI value was compared with the 2-week postoperative and 3-month postoperative values according to stabilization procedure (isolated MPFLr, isolated TTO, MPFLr + TTO, MPFLr + trochleoplasty, and MPFLr + trochleoplasty + TTO) using the paired t test. Analyses of the 1-bundle versus 2-bundle MPFLr technique and the presence of lateral retinacular release or lateral retinacular lengthening were conducted on the isolated MPFLr and combined MPFLr + TTO cohorts.

Results

A total of 356 knees were included. Statistically significant pre- to postoperative decreases in CDI were seen in all stabilization procedures analyzed (P≤ .017 for all). Within the isolated MPFLr cohort, this significant decrease was seen at 2 weeks postoperatively with the 2-bundle technique (ΔCDI = -0.09; P < .001) but not with the 1-bundle technique (ΔCDI = -0.01; P = .621).

Conclusion

The different surgical techniques analyzed in the current study affected patellar height, even when a distalizing TTO was not performed. The decrease was dependent on surgical technique, with a 2-bundle MPFLr leading to a statistically significant decrease and a 1-bundle MPFLr effecting no change.

ψ(2S) Suppression in Pb-Pb Collisions at the LHC

The production of the ψ(2S) charmonium state was measured with ALICE in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV, in the dimuon decay channel. A significant signal was observed for the first time at LHC energies down to zero transverse momentum, at forward rapidity (2.5 Collapse

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The Effect of Aspiration and Corticosteroid Injection After ACL Injury on Postoperative Infection Rate

BACKGROUND

Injecting bioactive substances into the knee is common in orthopaedic practice, and recently it has been shown to mitigate risk factors for posttraumatic osteoarthritis. Therefore, understanding the influence of these injections on postoperative infection rate is imperative.

HYPOTHESIS

Postinjury aspiration and corticosteroid injection (CSI) of the knee before anterior cruciate ligament (ACL) reconstruction (ACLR) would not increase the risk of postoperative infection.

STUDY DESIGN

Cohort Study; Level of evidence, 3.

METHODS

All patients between the ages of 10 and 65 years who underwent primary bone-patellar tendon-bone ACLR by 1 fellowship-trained sports medicine orthopaedic surgeon between January 1, 2011, and September 8, 2020, at 1 of 2 major academic centers were evaluated for inclusion. A total of 693 patients were included, with 273 patients receiving postinjury and preoperative aspiration and CSI. A postoperative infection was defined as a patient returning to the operating room for an intra-articular washout. The intervals-measured in days-between the CSI and ACLR and between ACLR and the final follow-up were recorded. To further evaluate the infection risk in each cohort (total cohort; aspiration and injection cohort; no aspiration and injection cohort), the upper 95% confidence bound for the infection risk was calculated for each cohort.

RESULTS

There were no postoperative infections in the 693 patients included in this study. The upper 95% confidence bounds were 0.4%, 1.1%, and 0.7% for the total cohort, the cohort that underwent aspiration and injection, and the cohort that did not, respectively. The median number of days between the surgical date and that of the aspiration and injection was 34 days, and the mean follow-up for the entire cohort was 337.4 days (95% CI, 307.6-367.3).

CONCLUSION

Postinjury and preoperative aspiration and CSI is a safe intervention that can be used before ACLR. Future studies with larger sample sizes, longer patient follow-ups, and multiple surgeons would be helpful to both better understand infection risk and better identify the influence of CSI on preventing posttraumatic osteoarthritis.

Posteromedial tibial plateau bone bruises are associated with medial meniscal ramp lesions in patients with concomitant anterior cruciate ligament ruptures: a systematic review & meta-analysis

OBJECTIVE

To determine if posteromedial tibial plateau (PMTP) bone bruising on pre-operative MRI is significantly associated with a ramp lesion identified during arthroscopy in patients with concomitant ACL ruptures.

METHODS

PubMed, CINAHL, Scopus, Web of Sciences, EMBASE, and Cochrane Library were searched systematically for studies that investigated the association between PMTP bone bruises on preoperative MRI and ramp lesions confirmed during arthroscopy. Eight studies met inclusion criteria. The Methodological Index for Nonrandomized Studies (MINORS) checklist was used to assess quality. A meta-analysis was performed to analyze odds of a ramp lesion after PMTP bone bruising identified on magnetic resonance imaging (MRI). Publication bias was assessed by funnel plot and Egger's linear regression test.

RESULTS

There are 2.05 greater odds of medial meniscal ramp lesions in patients with an ACL rupture when PMTP bone bruising is found on preoperative MRI (95% CI, 1.29-3.25; p = 0.002). Heterogeneity of the pooled studies may be substantial (I2 = 65%; p = 0.006). Funnel plot analysis and Egger's linear regression test (p > 0.5) determined no publication bias among the studies included in the meta-analysis.

CONCLUSION

Patients with acute ACL injuries and PMTP bone bruising on MRI have 2.05 times greater odds of a concomitant medial meniscal ramp lesion than those without this bone bruise pattern.

Measurements of Groomed-Jet Substructure of Charm Jets Tagged by D^{0} Mesons in Proton-Proton Collisions at sqrt[s]=13 TeV

Understanding the role of parton mass and Casimir color factors in the quantum chromodynamics parton shower represents an important step in characterizing the emission properties of heavy quarks. Recent experimental advances in jet substructure techniques have provided the opportunity to isolate and characterize gluon emissions from heavy quarks. In this Letter, the first direct experimental constraint on the charm-quark splitting function is presented, obtained via the measurement of the groomed shared momentum fraction of the first splitting in charm jets, tagged by a reconstructed D^{0} meson. The measurement is made in proton-proton collisions at sqrt[s]=13  TeV, in the low jet transverse-momentum interval of 15≤p_{T}^{jet ch}<30  GeV/c where the emission properties are sensitive to parton mass effects. In addition, the opening angle of the first perturbative emission of the charm quark, as well as the number of perturbative emissions it undergoes, is reported. Comparisons to measurements of an inclusive-jet sample show a steeper splitting function for charm quarks compared with gluons and light quarks. Charm quarks also undergo fewer perturbative emissions in the parton shower, with a reduced probability of large-angle emissions.

Measurement of the Lifetime and Λ Separation Energy of _{Λ}^{3}H

The most precise measurements to date of the _{Λ}^{3}H lifetime τ and Λ separation energy B_{Λ} are obtained using the data sample of Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV collected by ALICE at the LHC. The _{Λ}^{3}H is reconstructed via its charged two-body mesonic decay channel (_{Λ}^{3}H→^{3}He+π^{-} and the charge-conjugate process). The measured values τ=[253±11(stat)±6(syst)]  ps and B_{Λ}=[102±63(stat)±67(syst)]  keV are compatible with predictions from effective field theories and confirm that the _{Λ}^{3}H structure is consistent with a weakly bound system.

Factors Associated With Increased Opioid Prescriptions Following Anterior Cruciate Ligament Reconstruction in Opioid-Naïve Patients

Purpose

To identify the mean morphine milligram equivalent (MME) opioid prescriptions for opioid-naïve patients undergoing isolated anterior cruciate ligament reconstruction (ACLR) between 4 weeks before surgery and the first 90 days after surgery and to describe opioid prescriptions filled per patient and mean MMEs per year within 90 days following ACLR.

Methods

Exclusion criteria were patients having concurrent other cruciate or collateral ligament repair or reconstruction, meniscus procedures (repair and debridement), any cartilage procedure, lower-extremity osteotomy, or knee procedures for fracture, infection, or neoplasms; patients with substance use disorder or chronic pain also were excluded. Opioid use between 4 weeks before surgery and the first 90 days after surgery was recorded. Prescribing physician specialty also was tracked. The correlation of patient factors and prescriber specialty of MME were compared using the Student's t-test. Significance was defined at P < .05.

Results

Opioid-naïve patients undergoing isolated ACLR were included. Isolated arthroscopic ACLRs performed between 2010 and Q3 2020 in opioid-naïve patients were identified within the PearlDiver M91 national database. A total of 37,200 patients were identified. Mean MME per patient was 340.9 ± 198.2, with an average MME per day of 59.9. Factors associated with increased opioid use during the 90 days following ACLR were older age (P < .001) and preoperative diagnosis of depression (P < .001). Orthopaedic surgeons were primarily responsible for the number of opioid prescriptions after ACLR (n = 29,326, 73.0%) but 27% (n = 10,797) of prescriptions came from nonorthopaedic surgeon medical providers who prescribed significantly greater MMEs of opioids than orthopaedic surgeons (456.5 vs 339.2, P < .001) per patient. Lastly, decreasing yearly opioid prescriptions per patient (2.4 to 1.6 prescriptions) and the mean MME per patient (428.4 to 257.1) occurred from 2010 to 2020.

Conclusions

Older age and preoperative diagnosis of depression are associated with greater opioid doses after ACLR. In addition, the vast majority of opioid prescriptions are written by orthopaedic surgeons on the day of ACLR and decreased considerably by four weeks after surgery. Patients receiving opioid prescriptions by nonorthopaedic surgeon medical providers receive significantly greater doses.

Level of Evidence

Level IV, retrospective cohort study.

Measurement of the J/ψ Polarization with Respect to the Event Plane in Pb-Pb Collisions at the LHC

We study the polarization of inclusive J/ψ produced in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV at the LHC in the dimuon channel, via the measurement of the angular distribution of its decay products. We perform the study in the rapidity region 2.5 Collapse

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First Measurement of Antideuteron Number Fluctuations at Energies Available at the Large Hadron Collider

The first measurement of event-by-event antideuteron number fluctuations in high energy heavy-ion collisions is presented. The measurements are carried out at midrapidity (|η|<0.8) as a function of collision centrality in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV using the ALICE detector. A significant negative correlation between the produced antiprotons and antideuterons is observed in all collision centralities. The results are compared with a state-of-the-art coalescence calculation. While it describes the ratio of higher order cumulants of the antideuteron multiplicity distribution, it fails to describe quantitatively the magnitude of the correlation between antiproton and antideuteron production. On the other hand, thermal-statistical model calculations describe all the measured observables within uncertainties only for correlation volumes that are different with respect to those describing proton yields and a similar measurement of net-proton number fluctuations.

Enhanced Deuteron Coalescence Probability in Jets

The transverse-momentum (p_{T}) spectra and coalescence parameters B_{2} of (anti)deuterons are measured in p-p collisions at sqrt[s]=13  TeV for the first time in and out of jets. In this measurement, the direction of the leading particle with the highest p_{T} in the event (p_{T}^{lead}>5  GeV/c) is used as an approximation for the jet axis. The event is consequently divided into three azimuthal regions, and the jet signal is obtained as the difference between the toward region, that contains jet fragmentation products in addition to the underlying event (UE), and the transverse region, which is dominated by the UE. The coalescence parameter in the jet is found to be approximately a factor of 10 larger than that in the underlying event. This experimental observation is consistent with the coalescence picture and can be attributed to the smaller average phase-space distance between nucleons in the jet cone as compared with the underlying event. The results presented in this Letter are compared to predictions from a simple nucleon coalescence model, where the phase-space distributions of nucleons are generated using pythia8 with the Monash 2013 tuning, and to predictions from a deuteron production model based on ordinary nuclear reactions with parametrized energy-dependent cross sections tuned on data. The latter model is implemented in pythia8.3. Both models reproduce the observed large difference between in-jet and out-of-jet coalescence parameters, although the almost flat trend of the B_{2}^{Jet} is not reproduced by the models, which instead give a decreasing trend.

Measurement of Direct-Photon Cross Section and Double-Helicity Asymmetry at sqrt[s]=510 GeV in p[over →]+p[over →] Collisions

We present measurements of the cross section and double-helicity asymmetry A_{LL} of direct-photon production in p[over →]+p[over →] collisions at sqrt[s]=510  GeV. The measurements have been performed at midrapidity (|η|<0.25) with the PHENIX detector at the Relativistic Heavy Ion Collider. At relativistic energies, direct photons are dominantly produced from the initial quark-gluon hard scattering and do not interact via the strong force at leading order. Therefore, at sqrt[s]=510  GeV, where leading-order-effects dominate, these measurements provide clean and direct access to the gluon helicity in the polarized proton in the gluon-momentum-fraction range 0.02<x<0.08, with direct sensitivity to the sign of the gluon contribution.

Examining the Schenck KD I Classification in Patients With Documented Tibiofemoral Knee Dislocations: A Multicenter Retrospective Case Series

Background

Acute tibiofemoral knee dislocations (KDs) with a single cruciate ligament remaining intact are rare and can be classified as Schenck KD I. The inclusion of multiligament knee injuries (MLKIs) has contributed to a recent surge in Schenck KD I prevalence and has convoluted the original definition of the classification.

Purpose

To (1) report on a series of true Schenck KD I injuries with radiologically confirmed tibiofemoral dislocation and (2) introduce suffix modifications to further subclassify these injuries based on the reported cases.

Study Design

Case series; Level of evidence, 4.

Methods

A retrospective chart review identified all Schenck KD I MLKIs at 2 separate institutions between January 2001 and June 2022. Single-cruciate tears were included if a concomitant complete disruption of a collateral injury was present or injuries to the posterolateral corner, posteromedial corner, or extensor mechanism. All knee radiographs and magnetic resonance imaging scans were retrospectively reviewed by 2 board-certified orthopaedic sports medicine fellowship-trained surgeons. Only documented cases consistent with a complete tibiofemoral dislocation were included.

Results

Of the 227 MLKIs, 63 (27.8%) were classified as KD I, and 12 (19.0%) of the 63 KD I injuries had a radiologically confirmed tibiofemoral dislocation. These 12 injuries were subclassified based on the following proposed suffix modifications: KD I-DA (anterior cruciate ligament [ACL] only; n = 3), KD I-DAM (ACL + medial collateral ligament [MCL]; n = 3), KD I-DPM (posterior cruciate ligament [PCL] + MCL; n = 2), KD I-DAL (ACL + lateral collateral ligament [LCL]; n = 1), and KD I-DPL (PCL + LCL; n = 3).

Conclusion

The Schenck classification system should only be used to describe dislocations with bicruciate injuries or with single-cruciate injuries that have clinical and/or radiological evidence of tibiofemoral dislocation. Based on the presented cases, the authors recommend the suffix modifications for subclassifying Schenck KD I injuries with the goal of improving communication, surgical management, and the design of future outcome studies.

Incidence of Early Adverse Events After Tibial Tubercle Osteotomy

Background

Tibial tubercle osteotomy (TTO) is a commonly utilized surgical procedure for the treatment of patellofemoral instability. Although midterm and long-term outcomes are known, perioperative complications have not been consistently reported.

Purpose

To identify the incidence and predictors of adverse events in the first 90-day perioperative period after TTO.

Study Design

Case series; Level of evidence, 4.

Methods

Patients undergoing primary TTO between January 1, 2010, and December 31, 2019, were included. Readmissions in the first 90 days after surgery were collected, and data were collected for the following variables: age, sex, smoking status, body mass index, laterality, preoperative diagnosis, presence of trochlear dysplasia, tourniquet use, TTO procedure, tibial tubercle distalization, trochleoplasty, chondral procedure, number of screws, and use of an epidural catheter. Predictors of readmission for any reason were identified using multivariable logistic regression analysis.

Results

A total of 345 TTO procedures were included in the final analysis. The incidence of readmissions for any reason was 20.6% (71/345). The most common reason for readmission was postoperative pain (26/345 [7.5%]), followed by wound complications (19/345 [5.5%]) and epidural catheter-related complications (overall: 16/345 [4.6%]; specific: 16/167 [9.6%]. The incidence of major complications was 2.0% (7/345). The number of patients with each major complication was as follows: 1 for deep vein thrombosis, 2 for pulmonary embolism, 1 for septic arthritis, 1 for tibial tubercle fracture, and 2 for loss of fixation. Female sex and smoking were associated with readmission for pain.

Conclusion

The incidence of major complications after TTO was very low (2.0%), but 20.6% of cases required readmission, primarily for an indwelling epidural catheter (3.5%) and postoperative pain (7.5%). Concomitant soft tissue procedures and the number of screws were associated with readmission after TTO. Utilizing individualized postoperative pain management and preoperative discussions about expected pain may help to avoid readmission for pain after TTO.

Opioid Prescription Patterns 90 Days After Arthroscopic Rotator Cuff Repair: A 10-Year National Database Analysis

Background

Arthroscopic rotator cuff repair (ARCR) is a common procedure that typically requires opioid prescription for postoperative pain management.

Purpose

To investigate the current prescription patterns and factors influencing 90-day postoperative opioid prescription trends for opioid-naïve patients who underwent ARCR.

Study Design

Case series; Level of evidence, 4.

Methods

Opioid-naïve adult patients who underwent ARCR between January 2010 and September 2020 and had a record of opioid prescriptions during the 90-day postoperative period were identified in the PearlDiver Mariner91 national administrative database. Exclusions included patients with prior shoulder procedures, a history of chronic pain, and opioid prescription records dated earlier than 4 weeks before surgery. Covariates included age group, sex, Elixhauser Comorbidity Index, and prescriber specialty (orthopaedic or nonorthopaedic). The primary outcome-90-day postoperative morphine milligram equivalents (MMEs) prescribed per patient-was compared using univariate and multivariate regression analyses, and 90-day postoperative opioid prescription trends over the 10-year study period were analyzed with linear regression.

Results

In total, 55,345 ARCR cases were identified. The mean ± SD amount prescribed within the first 90 days was 742.4 ± 256.5 MMEs, and the median was 487.5 MMEs. Multivariate linear regression analysis predicted higher 90-day postoperative MMEs for female patients and younger patients (P < .01 for both). From 2010 to 2020, there was a 66% decrease in mean MME prescribed per patient (▵ = 660.4 MME; P < .01), with a mean reduction of 55.1 MME per patient per year. In 2020, the mean 90-day postoperative amount prescribed was 341.1 MME, which is equivalent to 51 tablets of 5-mg oxycodone (Percocet).

Conclusion

Female sex and younger age were predictors of more MME being prescribed after ARCR. While opioid prescriptions following ARCR have substantially decreased over the past decade, the amount prescribed warrants further attention.

Dual Posteromedial Portal Technique for Surgical Repair of an Unstable Medial Meniscal Ramp Lesion

Background:

Medial meniscal ramp lesions, which commonly occur in the setting of anterior cruciate ligament (ACL) ruptures, are defined as structural lesions at the medial meniscocapsular junction and can involve the posteromedial capsular attachments or most peripheral aspect of the meniscus. Unstable ramp lesions can lead to rotational instability within the knee and may play a role in ACL graft failure if left untreated. The novel use of dual posteromedial portals, similar to those used in an arthroscopic labral repair, may allow for enhanced visualization, optimal access to the posteromedial compartment, and easier manipulation of the instrumentation for successful surgical repair of hidden ramp lesions.

Indications:

Surgical repair of medial meniscal ramp lesions is indicated in patients with a clinically unstable meniscus when probed during arthroscopy.

Technique Description:

This surgical technique video demonstrates a dual posteromedial portal arthroscopic approach to repair an unstable medial meniscal ramp lesion using a case example from a patient with a concomitant ACL rupture.

Results:

Surgical repair of medial meniscal ramp lesions has been reported to show improvements in meniscus healing and knee stability.

Discussion/Conclusion:

The use of dual posteromedial portals offers improved accessibility to the posteromedial compartment of the knee and provides excellent visibility during the surgical repair of a medial meniscal ramp lesion. The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Preoperative Magnetic Resonance Imaging Offers Questionable Clinical Utility, Delays Time to Hip Arthroscopy, and Lacks Cost-Effectiveness in Patients Aged ≤40 Years With Femoroacetabular Impingement Syndrome: A Retrospective 5-Year Analysis

PURPOSE

To assess the clinical utility of preoperative magnetic resonance imaging (MRI) and quantify the delay in surgical care for patients aged ≤40 years undergoing primary hip arthroscopy with history, physical examination, and radiographs concordant with femoroacetabular impingement syndrome (FAIS).

METHODS

From August 2015 to December 2020, 1,786 consecutive patients were reviewed from the practice of 1 fellowship-trained hip arthroscopist. Inclusion criteria were FAIS, primary surgery, and age ≤40 years. Exclusion criteria were MRI contraindication, reattempt of conservative management, or concomitant periacetabular osteotomy. After nonoperative treatment options were exhausted and a surgical plan was established, patients were stratified by those who presented with versus without MRI. Those without existing MRI received one, and any deviations from the surgical plan were noted. All preoperative MRIs were compared with office evaluation and intraoperative findings to assess agreement. Demographic data, Hip Disability and Osteoarthritis Outcome Score (HOOS)-Pain, and time from office to MRI or arthroscopy were recorded.

RESULTS

Of the patients indicated by history, physical examination, and radiographs alone (70% female, body mass index 24.8 kg/m², age 25.9 years), 198 patients presented without MRI and 934 with MRI. None of the 198 had surgical plans altered after MRI. Patients in both groups had MRI findings demonstrating anterosuperior labral tears that were visualized and repaired intraoperatively. Mean time from office to arthroscopy for patients without MRI versus those with was 107.0 ± 67 and 85.0 ± 53 days, respectively (P < .001). Time to MRI was 22.8 days. No difference between groups was observed among the 85% of patients who surpassed the HOOS-Pain minimal clinically important difference (MCID).

CONCLUSION

Once indicated for surgery based on history, physical examination, and radiographs, preoperative MRI did not alter the surgical plan for patients aged ≤40 years with FAIS undergoing primary hip arthroscopy. Moreover, preoperative MRI delayed time to arthroscopy. The necessity of routine preoperative MRI in the young primary FAIS population should be challenged.

Posteromedial Tibial Bone Bruise After Anterior Cruciate Ligament Injury: An MRI Study of Bone Bruise Patterns in 208 Patients

Background:

Bone bruise patterns after anterior cruciate ligament (ACL) rupture may predict the presence of intra-articular pathology and help explain the mechanism of injury. Lateral femoral condyle (LFC) and lateral tibial plateau (LTP) bone bruises are pathognomic to ACL rupture. There is a lack of information regarding medial tibial plateau (MTP) and medial femoral condyle (MFC) bone bruises.

Purpose:

To summarize the prevalence and location of MTP bone bruises with acute ACL rupture and to determine the predictors of MTP bone bruises.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Inclusion criteria were patients who underwent ACL reconstruction between February 2015 and November 2017, magnetic resonance imaging (MRI) within 90 days of injury, and participation in the database. Exclusion criteria included previous ipsilateral surgery, multiligamentous injuries, and incomplete imaging. Due to the large number of cases remaining (n = 600), 150 patients were selected randomly from each year included in the study, for a total of 300 patients. Two readers independently reviewed injury MRI scans using the Costa-Paz bone bruise grading system. Logistic regression was used to identify factors associated with MTP bone bruises.

Results:

Included were 208 patients (mean age, 23.8 years; mean body mass index, 25.6). The mechanism of injury was noncontact in 59% of injuries, with over half from soccer, basketball, and football. The median time from injury to MRI scan was 12 days. Of the 208 patients, 98% (203/208) had a bone bruise, 79% (164/208) had an MTP bone bruise, and 83% (172/208) had bruises in both medial and lateral compartments. The most common pattern, representing 46.6% of patients (97/208), was a bruise in all 4 locations (MFC, LFC, MTP, and LTP). Of the 164 MTP bruises, 160 (98%) involved the posterior third of the plateau, and 161 were grade 1. The presence of an MFC bruise was the only independent risk factor for an MTP bruise (odds ratio, 3.71). The resulting nomogram demonstrated MFC bruise, sport, and mechanism of injury were the most important predictors of an MTP bruise.

Conclusion:

MTP bruise after acute ACL rupture was as prevalent as lateral bruises. The presence of a posterior MTP bruise suggested anterior tibial translation at the time of injury and could portend more medial compartment pathology at the time of injury than previously recognized.

Twenty-Year Outcomes After Anterior Cruciate Ligament Reconstruction: A Systematic Review of Prospectively Collected Data

BACKGROUND

Several long-term (≥20 years) follow-up studies after anterior cruciate ligament (ACL) reconstruction have been published in recent years, allowing for a systematic evaluation of outcomes.

PURPOSE

To summarize outcomes at ≥20 years after ACL reconstruction and identify patient and surgical factors that affect these results.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

Prospective studies of primary ACL reconstructions with hamstring or bone-patellar tendon-bone (BTB) autograft via an arthroscopic or a mini-open technique and with a mean follow-up of ≥20 years were identified. When possible, the mean scores for each outcome measure were calculated. Factors identified in individual studies as predictive of outcomes were described.

RESULTS

Five studies met the inclusion and exclusion criteria with a total of 2012 patients. The pooled mean follow-up for patient-reported outcome measures was 44.2% (range, 29.6%-92.7%) and in-person evaluation was 33.2% (range, 29.6%-48.9%). Four studies (n = 584) reported graft tears at a mean rate of 11.8% (range, 2%-18.5%) and 4 studies (n = 773) reported a contralateral ACL injury rate of 12.2% (range, 5.8%-30%). Repeat non-ACL arthroscopic surgery (4 studies; n = 177) to the ipsilateral knee occurred in 10.4% (range, 9.5%-18.3%) and knee arthroplasty (1 study; n = 217) in 5%. The pooled mean of the International Knee Documentation Committee subjective knee function (IKDC) score was 79.1 (SD, 21.8 [3 studies; n = 644]). In 2 studies (n?= 221), 57.5% of patients continued to participate in strenuous activities. The IKDC-objective score was normal or nearly normal in 82.3% (n = 496; 3 studies), with low rates of clinically significant residual laxity. Moderate-severe radiographic osteoarthritis (OA) (IKDC grade C or D) was present in 25.9% of patients (n = 605; 3 studies). Medial meniscectomy is associated with increased risk of radiographic OA. Radiographic OA severity is associated with worse patient-reported knee function, but the association with knee pain is unclear.

CONCLUSION

Currently available prospective evidence for ACL reconstruction with hamstring or BTB autograft provides several insights into outcomes at 20 years. The rates of follow-up at 20 years range from 30% to 93%. IKDC-objective scores were normal or nearly normal in 82% and the mean IKDC-subjective score was 79 points.

Factors Associated With Pain and Function Before Medial Patellofemoral Ligament Reconstruction

Background:

Medial patellofemoral ligament (MPFL) reconstruction is performed to treat recurrent patellar instability. Measurement of joint pain and function at the time of surgery has been demonstrated to be a predictor of the final outcomes in many surgical procedures.

Purpose/Hypothesis:

The purpose of this study was to evaluate the relationship between baseline patient characteristics, mental health, and intraoperative findings and patient-reported knee pain and function at the time of MPFL reconstruction. We hypothesized that patient characteristics and associated pathology would be associated with the degree of pain and dysfunction.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Included were skeletally mature patients who underwent unilateral open MPFL reconstruction between 2015 and 2020 at a single institution. Baseline descriptive information was collected, and the following outcome measures were administered preoperatively: the Veterans RAND 12-Item Health Survey Mental Component Score (VR-12 MCS) and the Knee injury and Osteoarthritis Outcome Score (KOOS) Pain, Physical Function Short Form (PS), and Quality of Life (QoL) subscales. Intraoperative findings were collected in a standardized format. Patient characteristics, preoperative variables, intraoperative findings, and VR-12 MCS were used as risk factors, and multivariate analysis was conducted to assess for relationships with the KOOS subscale scores.

Results:

In total, 201 patients with patella dislocations were included in this analysis. Intraoperatively, 122 patients (60.7%) had either normal cartilage or grade 1 or 2 cartilage injury, 79 patients (39.3%) had grade 3 or 4 cartilage injury, 35 patients (17.4%) had a loose body, and 3 patients (1.49%) had evidence of synovitis. Younger age (P = .012), male sex (P < .001), never having smoked (P = .029), and lower baseline VR-MCS (P < .001) were significantly associated with higher baseline KOOS Pain scores. Older age (P = .035), female sex (P = .003), higher body mass index (P = .005), and lower baseline VR-12 MCS (P < .001) were significantly associated with higher baseline KOOS PS scores. Younger age (P = .003), male sex (P < .001), lower baseline VR-12 MCS (P < .001), and no dysplasia (P = .023) were significantly associated with higher baseline KOOS QoL scores.

Conclusion:

Patient age, sex, and baseline VR-12 MCS were associated with all 3 baseline KOOS subscale scores, whereas intraoperative findings outside of trochlear dysplasia were not associated with any of the KOOS subscale scores.

Treatment options for complex shoulder osteoarthritis with posterior humeral head subluxation and glenoid bone loss (Walch B): A systematic review

Background

Shoulder osteoarthritis (OA) with eccentric (B) glenoids has generally been associated with poor patient-reported outcomes and increased complications. The purpose of this study was to outline all the described treatment options and their outcomes and complications in order to better guide treatment.

Methods

This systematic review was performed according to the Preferred Reporting Items for Systematic review and Meta-analysis guidelines. Searches were performed up to December 19, 2019, using Medline, EMBASE, Scopus, and Cochrane databases. Inclusion criteria included studies for glenohumeral OA reporting posterior humeral head subluxation and/or posterior glenoid erosion. Studies were excluded if they were review papers, abstracts, or conference papers; had heterogeneity of included Walch types; or were not written in English.

Results

Twenty-one studies met inclusion criteria. The mean follow-up duration was 47.5 months (range, 14-300), and the mean patient age 62 years (38-88). Six different discernible techniques were identified: asymmetric reaming with onlay glenoid (AROG) in 267 shoulders, posterior glenoid bone grafting (PGBG) with onlay glenoid in 79 shoulders, augmented glenoid (AG) in 160 shoulders, reverse shoulder arthroplasty (RSA) with or without bone grafting in 118 shoulders, hemiarthroplasty with concentric reaming (HACR) in 57 shoulders, and humeral head arthroplasty with inlay glenoid (HAIG) in 36 shoulders. All techniques reported improved patient outcomes and range of motion. Short-term (<5 years) studies reported glenoid loosening leading to revisions in 3% of AROG, 2.7% PGBG, 0.8% AG, 1.4% RSA, and 0% HAIG shoulders. HACR had a high revision rate (12.3%) due to persistent pain and stiffness. Midterm (>5 years) studies demonstrated increased rates of glenoid loosening with AROG (14.5%), PGBG (21% loose, 23.8% "at risk"), and AG (18.9% "at risk"), as well as increased rates of subluxation or revision due to instability. HAIG did not demonstrate loosening, subluxation, or revision at 55.2 months.

Conclusion

Various techniques exist to manage complex primary glenohumeral OA with posterior subluxation and posterior glenoid erosion. Glenoid component survival is a concern with ASOG, PGBG, and AG. HACR has the highest early revision rate. RSA offers promising short-term and midterm results likely due to the advantage of more secure fixation as well as a constrained design to prevent posterior subluxation. HAIG has the lowest complication and revision rates although further long-term studies are needed.

Do Patellar Tendon Repairs Have Better Outcomes than Quadriceps Tendon Repairs? A Prospective Cohort Analysis

Patellar tendon (PT) and quadriceps tendon (QT) ruptures represent significant injuries and warrant surgical intervention in most patients. Outcome data are predominantly retrospective analyses with low sample sizes. There are also minimal data comparing QT and PT repairs and the variables impacting patient outcomes. The level of evidence of the study is level II (prognosis). From the prospective OME cohort, 189 PT or QT repairs were performed between February 2015 and October 2019. Of these, 178 were successfully enrolled (94.2%) with 1-year follow-up on 141 (79.2%). Baseline demographic data included age, sex, race, BMI, years of education, smoking status, and baseline VR-12 MCS score. Surgical and follow-up data included surgeon volume, fixation technique, baseline, and 1-year Knee Injury and Osteoarthritis Outcome Score-Pain (KOOS-Pain), Knee Injury and Osteoarthritis Outcome Score-Physical Function (KOOS-PS), and 1-year Patient Acceptable Symptom State (PASS) scores and complications. Multivariable regression analysis was utilized to identify prognosis and significant risk factors for outcomes-specifically, whether KOOS-Pain or KOOS-PS were different between QT versus PT repairs. There were 59 patients in the PT cohort and 82 patients in QT cohort. Baseline demographic data demonstrated that PT cohort was younger (45.1 vs. 59.5 years, p <0.001), included significantly fewer patients of White race (51.7 vs. 80.0%, p = 0.001), lesser number of years of education (13.9 vs. 15.2 years, p = 0.020), a higher percentage of "high" surgeon volume (72.9% vs. 43.9%, p = 0.001) and 25.4% of PT repairs had supplemental fixation (QT had zero, p <0.001). Multivariable analysis identified gender (female-worse, p = 0.001), years of education (higher-better, p = 0.02), and baseline KOOS-Pain score (higher-better, p <0.001) as the risk factors that significantly predicted KOOS-Pain score. The risk factors that significantly predicted KOOS-PS were gender (female worse, p = 0.033), race (non-White-worse, p <0.001), baseline VR-12 MCS score (higher-better, p <0.001), and baseline KOOS-PS score (higher better, p = 0.029). KOOS-Pain and KOOS-PS scores improved after both QT and PT repairs. Patient reported pain and function at 1 year were similar between PT and QT repairs after adjusting for known risk factors. Multivariable analysis identified female gender and low baseline KOOS scores as predictors for worse outcomes.

Hypertriton Production in p-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

The study of nuclei and antinuclei production has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. The first measurement of the production of _{Λ}^{3}H in p-Pb collisions at sqrt[s_{NN}]=5.02  TeV is presented in this Letter. Its production yield measured in the rapidity interval -1<y<0 for the 40% highest-multiplicity p-Pb collisions is dN/dy=[6.3±1.8(stat)±1.2(syst)]×10^{-7}. The measurement is compared with the expectations of statistical hadronization and coalescence models, which describe the nucleosynthesis in hadronic collisions. These two models predict very different yields of the hypertriton in charged particle multiplicity environments relevant to small collision systems such as p-Pb, and therefore the measurement of dN/dy is crucial to distinguish between them. The precision of this measurement leads to the exclusion with a significance larger than 6.9σ of some configurations of the statistical hadronization model, thus constraining the theory behind the production of loosely bound states at hadron colliders.

Polarization of Λ and Λ[over ¯] Hyperons along the Beam Direction in Pb-Pb Collisions at sqrt[s]_{NN}=5.02 TeV

The polarization of the Λ and Λ[over ¯] hyperons along the beam (z) direction, P_{z}, has been measured in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV recorded with ALICE at the Large Hadron Collider (LHC). The main contribution to P_{z} comes from elliptic flow-induced vorticity and can be characterized by the second Fourier sine coefficient P_{z,s2}=⟨P_{z}sin(2φ-2Ψ_{2})⟩, where φ is the hyperon azimuthal emission angle and Ψ_{2} is the elliptic flow plane angle. We report the measurement of P_{z,s2} for different collision centralities and in the 30%-50% centrality interval as a function of the hyperon transverse momentum and rapidity. The P_{z,s2} is positive similarly as measured by the STAR Collaboration in Au-Au collisions at sqrt[s_{NN}]=200  GeV, with somewhat smaller amplitude in the semicentral collisions. This is the first experimental evidence of a nonzero hyperon P_{z} in Pb-Pb collisions at the LHC. The comparison of the measured P_{z,s2} with the hydrodynamic model calculations shows sensitivity to the competing contributions from thermal and the recently found shear-induced vorticity, as well as to whether the polarization is acquired at the quark-gluon plasma or the hadronic phase.

Measurement of the Groomed Jet Radius and Momentum Splitting Fraction in pp and Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

This article presents groomed jet substructure measurements in pp and Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV with the ALICE detector. The soft drop grooming algorithm provides access to the hard parton splittings inside a jet by removing soft wide-angle radiation. We report the groomed jet momentum splitting fraction, z_{g}, and the (scaled) groomed jet radius, θ_{g}. Charged-particle jets are reconstructed at midrapidity using the anti-k_{T} algorithm with resolution parameters R=0.2 and R=0.4. In heavy-ion collisions, the large underlying event poses a challenge for the reconstruction of groomed jet observables, since fluctuations in the background can cause groomed parton splittings to be misidentified. By using strong grooming conditions to reduce this background, we report these observables fully corrected for detector effects and background fluctuations for the first time. A narrowing of the θ_{g} distribution in Pb-Pb collisions compared to pp collisions is seen, which provides direct evidence of the modification of the angular structure of jets in the quark-gluon plasma. No significant modification of the z_{g} distribution in Pb-Pb collisions compared to pp collisions is observed. These results are compared with a variety of theoretical models of jet quenching, and provide constraints on jet energy-loss mechanisms and coherence effects in the quark-gluon plasma.

Design Features and Rationale of the BEAR-MOON (Bridge-Enhanced ACL Restoration Multicenter Orthopaedic Outcomes Network) Randomized Clinical Trial

Background:

BEAR (bridge-enhanced anterior cruciate ligament [ACL] restoration), a paradigm-shifting technology to heal midsubstance ACL tears, has been demonstrated to be effective in a single-center 2:1 randomized controlled trial (RCT) versus hamstring ACL reconstruction. Widespread dissemination of BEAR into clinical practice should also be informed by a multicenter RCT to demonstrate exportability and compare efficacy with bone--patellar tendon–bone (BPTB) ACL reconstruction, another clinically standard treatment.

Purpose:

To present the design and initial preparation of a multicenter RCT of BEAR versus BPTB ACL reconstruction (the BEAR: Multicenter Orthopaedic Outcomes Network [BEAR-MOON] trial). Design and analytic issues in planning the complex BEAR-MOON trial, involving the US National Institute of Arthritis and Musculoskeletal and Skin Diseases, the US Food and Drug Administration, the BEAR implant manufacturer, a data and safety monitoring board, and institutional review boards, can usefully inform both clinicians on the trial’s strengths and limitations and future investigators on planning of complex orthopaedic studies.

Study Design:

Clinical trial.

Methods:

We describe the distinctive clinical, methodological, and operational challenges of comparing the innovative BEAR procedure with the well-established BPTB operation, and we outline the clinical motivation, experimental setting, study design, surgical challenges, rehabilitation, outcome measures, and planned analysis of the BEAR-MOON trial.

Results:

BEAR-MOON is a 6-center, 12-surgeon, 200-patient randomized, partially blinded, noninferiority RCT comparing BEAR with BPTB ACL reconstruction for treating first-time midsubstance ACL tears. Noninferiority of BEAR relative to BPTB will be claimed if the total score on the International Knee Documentation Committee (IKDC) subjective knee evaluation form and the knee arthrometer 30-lb (13.61-kg) side-to-side laxity difference are both within respective margins of 16 points for the IKDC and 2.5 mm for knee laxity.

Conclusion:

Major issues include patient selection, need for intraoperative randomization and treatment-specific postoperative physical therapy regimens (because of fundamental differences in surgical technique, initial stability construct, and healing), and choice of noninferiority margins for short-term efficacy outcomes of a novel intervention with evident short-term advantages and theoretical, but unverified, long-term benefits on other dimensions.

Measurement of Prompt D^{0}, Λ_{c}^{+}, and Σ_{c}^{0,++}(2455) Production in Proton-Proton Collisions at sqrt[s]=13 TeV

The p_{T}-differential production cross sections of prompt D^{0}, Λ_{c}^{+}, and Σ_{c}^{0,++}(2455) charmed hadrons are measured at midrapidity (|y|<0.5) in pp collisions at sqrt[s]=13  TeV. This is the first measurement of Σ_{c}^{0,++} production in hadronic collisions. Assuming the same production yield for the three Σ_{c}^{0,+,++} isospin states, the baryon-to-meson cross section ratios Σ_{c}^{0,+,++}/D^{0} and Λ_{c}^{+}/D^{0} are calculated in the transverse momentum (p_{T}) intervals 2<p_{T}<12 and 1<p_{T}<24  GeV/c. Values significantly larger than in e^{+}e^{-} collisions are observed, indicating for the first time that baryon enhancement in hadronic collisions also extends to the Σ_{c}. The feed-down contribution to Λ_{c}^{+} production from Σ_{c}^{0,+,++} is also reported and is found to be larger than in e^{+}e^{-} collisions. The data are compared with predictions from event generators and other phenomenological models, providing a sensitive test of the different charm-hadronization mechanisms implemented in the models.

Measurement of the Cross Sections of Ξ_{c}^{0} and Ξ_{c}^{+} Baryons and of the Branching-Fraction Ratio BR(Ξ_{c}^{0}→Ξ^{-}e^{+}ν_{e})/BR(Ξ_{c}^{0}→Ξ^{-}π^{+}) in pp Collisions at sqrt[s]=13 TeV

The p_{T}-differential cross sections of prompt charm-strange baryons Ξ_{c}^{0} and Ξ_{c}^{+} were measured at midrapidity (|y|<0.5) in proton-proton (pp) collisions at a center-of-mass energy sqrt[s]=13  TeV with the ALICE detector at the LHC. The Ξ_{c}^{0} baryon was reconstructed via both the semileptonic decay (Ξ^{-}e^{+}ν_{e}) and the hadronic decay (Ξ^{-}π^{+}) channels. The Ξ_{c}^{+} baryon was reconstructed via the hadronic decay (Ξ^{-}π^{+}π^{+}) channel. The branching-fraction ratio BR(Ξ_{c}^{0}→Ξ^{-}e^{+}ν_{e})/BR(Ξ_{c}^{0}→Ξ^{-}π^{+})=1.38±0.14(stat)±0.22(syst) was measured with a total uncertainty reduced by a factor of about 3 with respect to the current world average reported by the Particle Data Group. The transverse momentum (p_{T}) dependence of the Ξ_{c}^{0}- and Ξ_{c}^{+}-baryon production relative to the D^{0} meson and to the Σ_{c}^{0,+,++}- and Λ_{c}^{+}-baryon production are reported. The baryon-to-meson ratio increases toward low p_{T} up to a value of approximately 0.3. The measurements are compared with various models that take different hadronization mechanisms into consideration. The results provide stringent constraints to these theoretical calculations and additional evidence that different processes are involved in charm hadronization in electron-positron (e^{+}e^{-}) and hadronic collisions.

Λ_{c}^{+} Production and Baryon-to-Meson Ratios in pp and p-Pb Collisions at sqrt[s_{NN}]=5.02 TeV at the LHC

The prompt production of the charm baryon Λ_{c}^{+} and the Λ_{c}^{+}/D^{0} production ratios were measured at midrapidity with the ALICE detector in pp and p-Pb collisions at sqrt[s_{NN}]=5.02  TeV. These new measurements show a clear decrease of the Λ_{c}^{+}/D^{0} ratio with increasing transverse momentum (p_{T}) in both collision systems in the range 2<p_{T}<12  GeV/c, exhibiting similarities with the light-flavor baryon-to-meson ratios p/π and Λ/K_{S}^{0}. At low p_{T}, predictions that include additional color-reconnection mechanisms beyond the leading-color approximation, assume the existence of additional higher-mass charm-baryon states, or include hadronization via coalescence can describe the data, while predictions driven by charm-quark fragmentation processes measured in e^{+}e^{-} and e^{-}p collisions significantly underestimate the data. The results presented in this Letter provide significant evidence that the established assumption of universality (colliding-system independence) of parton-to-hadron fragmentation is not sufficient to describe charm-baryon production in hadronic collisions at LHC energies.

Excessive screen time and lower psychosocial well-being among preschool children

OBJECTIVE

Too much screen time is a common and severe threat to child health and excessive screen exposure exists in the early childhood population in Turkey. We aimed to investigate the associations between excessive screen time and psychosocial well-being in a sample of Turkish preschool children.

METHODS

Mothers and their healthy children aged 2-5 years who applied to general pediatric outpatient clinics for well-child examinations were enrolled in this descriptive cross-sectional study. Children with a daily screen time of less than 1 h (low) or more than or equal to 4 h (excessive) were included. Psychosocial well-being was assessed using the parent version of the Strengths and Difficulties Questionnaire.

RESULTS

In all, 220 mother-child pairs participated in this study. Emotional symptoms, conduct problems, peer relationship problems, and total difficulties scores were significantly higher in the children with excessive screen time (p<0.05), while the hyperactivity-inattention and prosocial scores were not different between the low and excessive screen time groups (p>0.05). After adjusting for potential confounders, the children with excessive screen time had significantly increased odds ratios for having conduct and peer relationship problems (OR [95% CI]: 2.62 [1.11-6.19], p = 0.028 and 2.57 [1.25-5.26], p = 0.010, respectively).

CONCLUSION

Turkish preschool children with excessive screen time were significantly more likely to have poor psychosocial well-being. Preschool children with behavioral problems should be evaluated for excessive screen time.

Experimental Evidence for an Attractive p-ϕ Interaction

This Letter presents the first experimental evidence of the attractive strong interaction between a proton and a ϕ meson. The result is obtained from two-particle correlations of combined p-ϕ⊕ p[over ¯]-ϕ pairs measured in high-multiplicity pp collisions at sqrt[s]=13  TeV by the ALICE Collaboration. The spin-averaged scattering length and effective range of the p-ϕ interaction are extracted from the fully corrected correlation function employing the Lednický-Lyuboshits approach. In particular, the imaginary part of the scattering length vanishes within uncertainties, indicating that inelastic processes do not play a prominent role for the p-ϕ interaction. These data demonstrate that the interaction is dominated by elastic p-ϕ scattering. Furthermore, an analysis employing phenomenological Gaussian- and Yukawa-type potentials is conducted. Under the assumption of the latter, the N-ϕ coupling constant is found to be g_{N-ϕ}=0.14±0.03(stat)±0.02(syst). This work provides valuable experimental input to accomplish a self-consistent description of the N-ϕ interaction, which is particularly relevant for the more fundamental studies on partial restoration of chiral symmetry in nuclear medium.

Probing Gluon Spin-Momentum Correlations in Transversely Polarized Protons through Midrapidity Isolated Direct Photons in p^{↑}+p Collisions at sqrt[s]=200 GeV

Studying spin-momentum correlations in hadronic collisions offers a glimpse into a three-dimensional picture of proton structure. The transverse single-spin asymmetry for midrapidity isolated direct photons in p^{↑}+p collisions at sqrt[s]=200  GeV is measured with the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). Because direct photons in particular are produced from the hard scattering and do not interact via the strong force, this measurement is a clean probe of initial-state spin-momentum correlations inside the proton and is in particular sensitive to gluon interference effects within the proton. This is the first time direct photons have been used as a probe of spin-momentum correlations at RHIC. The uncertainties on the results are a 50-fold improvement with respect to those of the one prior measurement for the same observable, from the Fermilab E704 experiment. These results constrain gluon spin-momentum correlations in transversely polarized protons.

Outcomes of Pediatric Posterior Cruciate Ligament Reconstruction: A Systematic Review

Background

Little has been reported in the literature regarding surgical treatment of posterior cruciate ligament (PCL) injuries in pediatric patients.

Purpose/Hypothesis

The purpose was to evaluate presentation, injury pattern, outcomes, and complications of surgically managed PCL injuries in pediatric patients. It was hypothesized that pediatric patients would have good patient-reported outcomes and no significant radiographic changes or complications.

Study Design

Systematic review; Level of evidence, 4.

Methods

A literature search was performed using PubMed, Medline, EMBASE, Scopus, and Cochrane databases between 1975 and December 16, 2019. Search terms included "posterior cruciate ligament," "peel-off injury," "avulsion," "PCL," "pediatric," "skeletally immature," and "adolescent." Included were studies on pediatric patients with PCL injuries managed operatively. Exclusion criteria included case reports, studies not reporting clinical results, reviews, abstract or conference papers, or papers not in the English language. Quality assessment was performed on all included studies using the MINORS (Methodological Index for Non-Randomized Studies) criteria.

Results

Four articles comprising 43 knees in 42 patients met the criteria and were included. Motor vehicle accidents were the most common mechanism of injury (39.5%; n = 17/43), followed by sports-related injuries (35%; n = 15/43). All studies commented on tear pattern, with the following distribution: 42% (n = 18/43) midsubstance tears, 37% (n = 16/43) tibial avulsions, and 21% (n = 9/43) femoral avulsions. Overall, good patient-reported outcomes (Knee injury and Osteoarthritis Outcome Score and Pediatric International Knee Documentation Committee, Tegner, and Lysholm scores) and return to activity, as well as satisfactory posterior stability (KT-1000 arthrometer, posterior drawer test, and kneeling radiographs) and range of motion, were reported. There was no significant leg-length discrepancy or angular deformity reported. Arthrofibrosis was reported in 7% of postoperative knees and was the most commonly reported complication. Osteoarthritis was reported in 21% (n = 9/43) of knees. The average MINORS score was 7 (range, 6-8) for noncomparative studies and 10 for comparative studies.

Conclusion

Good patient-reported outcomes and return to activity can be obtained using repair or reconstruction. This evidence was limited by the quality of the included studies and overall small sample size; however, this review serves as a baseline for futures studies on PCL repair/reconstruction in pediatric patients.

Multiharmonic Correlations of Different Flow Amplitudes in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV

The event-by-event correlations between three flow amplitudes are measured for the first time in Pb-Pb collisions, using higher-order symmetric cumulants. We find that different three-harmonic correlations develop during the collective evolution of the medium when compared to correlations that exist in the initial state. These new results cannot be interpreted in terms of previous lower-order flow measurements since contributions from two-harmonic correlations are explicitly removed in the new observables. A comparison to Monte Carlo simulations provides new and independent constraints for the initial conditions and system properties of nuclear matter created in heavy-ion collisions.

Effect of temperature manipulation during incubation on body weight, plasma parameters, muscle histology, and expression of myogenic genes in breast muscle of embryos and broiler chickens from two commercial strains

1. This study evaluated the effect of a higher incubation temperature on body weight, plasma profile, histology and expression of myogenin (MYOG), insulin-like growth factor-I (IGF-I) and vascular endothelial growth factor A (VEGFA) genes in breast muscle of embryos and broilers from two commercial strains.2. A total of 784 eggs from Ross 308 and Cobb 500 broiler breeder flocks were used. Half of the eggs per strain were incubated at control temperature (37.8°C), whereas the other half were exposed to heat treatment (HT) of 38.8°C between embryonic day (ED) 10 and 14, for 6 h/day. Embryos and chicks were sampled on ED 19 and at hatch. A total of 480, one-day-old chicks per strain and incubation temperature were reared up to 42 d post-hatch.3. The HT increased hatch weight of Ross chicks and 42-d body weight of broilers from both strains. Lower plasma triacylglycerol levels were measured for HT embryos and broilers on ED 19 and 42 d post-hatch, respectively. HT reduced plasma T₃ levels in Ross embryos and broilers for the same periods. Hepatic TBARS concentrations were elevated by HT compared to the control incubation.4. The HT reduced breast muscle VEGFA gene expression of Cobb embryos on ED 19, whereas expression was stimulated in day-old chicks. At 42 d post-hatch, fibre area was increased by HT regardless of strain. Compared to the control incubation, HT increased the breast yield of Ross broilers and leg yield of Cobb. Ross-HT broilers had a higher pH at 24 h after slaughter and better water holding capacity than Cobb-HT broilers.5. These results suggested that HT increased body weight, fibre area, IGF-I gene expression and lowered plasma triacylglycerol levels of broiler chickens from both strains at 42 d. However, HT influenced the expression of VEGF-A and MYOG genes and meat quality differently between the broiler strains.

Clinical and Radiographic Outcomes of Total Shoulder Arthroplasty With a Nonspherical Humeral Head and Inlay Glenoid in Elite Weight Lifters: A Prospective Case Series

Background:

Weight lifting after total shoulder arthroplasty (TSA) can place significant stresses on implants that could lead to instability, loosening, and increased wear. A TSA system with nonspherical humeral head resurfacing and inlay glenoid—which improves the biomechanics and thus reduces instability, wear, and potential loosening—may be able to tolerate repetitive loads from weight lifting.

Purpose:

To determine clinical and radiographic outcomes after TSA in weight lifters.

Study Design:

Case series; Level of evidence, 4.

Methods:

We prospectively enrolled 16 weight lifters (mean ± SD age, 57.2 ± 7.8 years; 15 male) undergoing primary anatomic TSA (n = 17 shoulders, 1 staged bilateral) with nonspherical humeral head resurfacing and inlay glenoid replacement for glenohumeral osteoarthritis between February 2015 and February 2019. Exclusion criteria were rotator cuff deficiency, revision TSA, post-traumatic arthritis, and inflammatory arthritis. Outcome measures included the rate of return to weight lifting, results of patient-reported outcome measures (Penn Shoulder Score, Kerlan-Jobe Orthopaedic Clinic, and 12-Item Veterans RAND Health Survey), radiographic outcomes, and complication rate.

Results:

Follow-up was obtained on all patients at a mean of 38 months (range, 14-63 months). All patients returned to competitive weight lifting at 15.6 ± 6.9 weeks. Compared to the preoperative weight lifting level, at last follow-up patients reported performance at the following level: lighter weight, 1 (6%); same weight, 8 (50%); heavier weight, 7 (44%). Preoperative eccentric posterior glenoid wear was common (71% Walch B2 classification; 12/17), but posterior humeral subluxation improved at follow-up according to the Walch index (mean, 55.5% preoperative vs 48.5% postoperative; P < .001) and contact point ratio (mean, 63.9% preoperative vs 50.1% postoperative; P < .001). Pre- to postoperative improvements were seen in Penn Shoulder Score (44.3 vs 82.6; P < .001), Kerlan-Jobe Orthopaedic Clinic (50.6 vs 91.1; P < .001), and 12-Item Veterans RAND Health Survey physical component score but not mental component score. No signs of radiographic loosening were detected in follow-up images, nor were there any postoperative instability episodes or revision surgeries.

Conclusion:

There were substantial improvements in shoulder function and a high rate of return to weight lifting after TSA with a nonspherical humeral head resurfacing and inlay glenoid component. Radiographically, the humeral head centralized on the glenoid after surgery, and there was no evidence of component loosening at a mean 38-month follow-up.

Soft-Dielectron Excess in Proton-Proton Collisions at sqrt[s]=13 TeV

A measurement of dielectron production in proton-proton (pp) collisions at sqrt[s]=13  TeV, recorded with the ALICE detector at the CERN LHC, is presented in this Letter. The data set was recorded with a reduced magnetic solenoid field. This enables the investigation of a kinematic domain at low dielectron (ee) invariant mass m_{ee} and pair transverse momentum p_{T,ee} that was previously inaccessible at the LHC. The cross section for dielectron production is studied as a function of m_{ee}, p_{T,ee}, and event multiplicity dN_{ch}/dη. The expected dielectron rate from hadron decays, called hadronic cocktail, utilizes a parametrization of the measured η/π^{0} ratio in pp and proton-nucleus collisions, assuming that this ratio shows no strong dependence on collision energy at low transverse momentum. Comparison of the measured dielectron yield to the hadronic cocktail at 0.15<m_{ee}<0.6  GeV/c^{2} and for p_{T,ee}<0.4  GeV/c indicates an enhancement of soft dielectrons, reminiscent of the "anomalous" soft-photon and soft-dilepton excess in hadron-hadron collisions reported by several experiments under different experimental conditions. The enhancement factor over the hadronic cocktail amounts to 1.61±0.13(stat)±0.17(syst,data)±0.34(syst,cocktail) in the ALICE acceptance. Acceptance-corrected excess spectra in m_{ee} and p_{T,ee} are extracted and compared with calculations of dielectron production from hadronic bremsstrahlung and thermal radiation within a hadronic many-body approach.

Total Shoulder Arthroplasty Using OVO®/OVO® Motion with Inlay Glenoid Shoulder Arthroplasty System

The incidence of patients undergoing total shoulder arthroplasty (TSA) for glenohumeral osteoarthritis has been steadily increasing in the United States. TSA with humeral head resurfacing with an inlay glenoid using OVO®/OVO® Motion (Arthrosurface, Inc., Franklin, Massachusetts) is an anatomic implant solution to shoulder arthritis. Anatomic resurfacing has demonstrated promising clinical- and patient-reported outcomes in the literature in both active and low-demand patients. Furthermore, patients are capable of returning to high-demand activities, such as weightlifting, which are restricted with conventional total shoulder replacement designs. Resurfacing designs offer a simple solution to a complex problem.

Patellar Tendon Imbrication

Background:

Patella alta is a common cause of patellar instability. Patellar tendon imbrication is a successful surgery addressing the deformity by shortening the patellar tendon without necessitating an osteotomy.

Indications:

Symptomatic patella alta causing patellar instability in both skeletally immature and adult patients.

Technique Description:

The patellar tendon is exposed, and levels of imbrication as determined preoperatively by radiographic measurements are outlined on the tendon with a marking pen. A third line is then made proximal to the level of dissection that is half the distance of the lengthening. From the distal marking, a flap of tendon, the anterior half, is elevated by sharp dissection using a fresh No. 15 blade proximal to the predetermined level. Next, “redundancy-reducing” 2-0 vicryl sutures are placed and left untied by entering at the proximal marking, passing deep to the tendon, and emerging at the middle of the intact posterior section of tendon, followed by placement of 3 structural #2 Ethibond/Ti-Cron horizontal sutures into the patellar tendon that will create and maintain the imbrication. These sutures are then tied proximally while applying downward pressure to the patella to avoid tying under tension. Next, the “redundancy-reducing” sutures are tied thus imbricating the redundant posterior section of tendon. In a “pants over vest” fashion, the distal end of the anterior section of isolated tendon is repaired with ‘‘0’’ absorbable suture. The knee is then flexed beyond 90° to assess competence of the suture lines and to assess the need for quadriceps lengthening.

Results:

Radiographic shortening is maintained at a minimum of 2 years on 27 patients/32 knees. There were no complications directly related to the technique.

Discussion/Conclusion:

Patellar tendon imbrication is a safe and effective procedure to correct patella alta in the setting of lateral patellar instability. On average, the technique allowed 1 cm of patellar tendon shortening and maintained the correction at a minimum 2-year follow-up. In the skeletally immature patient, this technique allows correction of patella alta by avoidance of a tibial tuberosity osteotomy.