Shoulder Arthroplasty in the Upper Extremity Weight-bearing Patient: A Systematic Review of Clinical Outcomes and Complications.

BACKGROUND: Patients who rely on their upper extremities for ambulation, or upper extremity ambulators (UEAs), place considerable stress on their shoulders through the use of assistive devices like walkers, crutches, canes, and wheelchairs. It has been postulated that UEAs may be at increased risk for complications following shoulder arthroplasty. This study aimed to systematically review the literature related to (1) patient-reported outcomes measures (PROMs), (2) functional outcomes, and (3) complications in UEAs who undergo shoulder arthroplasty. METHODS: A systematic review of the PubMed/MEDLINE, Embase, and Cochrane databases was performed to identify studies reporting clinical outcomes of shoulder arthroplasty in UEAs. Patient demographics, clinical characteristics, PROMs, radiographic outcomes, and postoperative range of motion were collected and compared to control patients (i.e. bipedal ambulators) from the constituent studies. RESULTS: A total of eight studies evaluating 248 UEA cases and 206 control cases were included for review. Ambulatory assistive devices utilized by UEAs included walkers (39%), wheelchairs (38%), canes (22%), and a crutch (<1%). Among UEA cases, 197 (79%) reverse total shoulder arthroplasty, 37 (15%) anatomic total shoulder arthroplasty, and 14 (6%) hemiarthroplasty were performed. Overall, patients exhibited significant improvements in mean American Shoulder and Elbow Surgeons (ASES) scores, Constant-Murley scores, Simple Shoulder Test (SST) scores, and Visual Analog Scale (VAS) scores postoperatively. Among 3 studies that included comparison with control groups of bipedal ambulators, no significant differences in outcomes were identified. The overall clinical complication rate was 17% for UEAs compared to 9.1% for controls. The rate of revision surgery was 7.7% for UEAs and 4.9% for bipedal ambulators. CONCLUSIONS: UEAs experience satisfactory pain relief, functional improvements, and good subjective outcomes following shoulder arthroplasty. However, complication and revision rates are higher compared to those for bipedal ambulators, and the majority of UEAs undergo reverse shoulder arthroplasty (RSA) compared to anatomic total shoulder arthroplasty (aTSA).

Deciphering the role of glycosaminoglycans in GPCR signaling.

G protein-coupled receptors (GPCR) and glycosaminoglycans (GAGs) are two essential components of the cell surface that regulate physiological processes in the body. GPCRs are the most extensive family of transmembrane receptors that control cellular responses to extracellular stimuli, while GAGs are polysaccharides that contribute to the function of the extracellular matrix (ECM). Due to their proximity to the plasma membrane, GAGs participate in signal transduction by interacting with various extracellular molecules and cell surface receptors. GAGs can directly interact with certain GPCRs or their ligands (chemokines, peptide hormones and neuropeptides, structural proteins, and enzymes) from the glutamate receptor family, the rhodopsin receptor family, the adhesion receptor family, and the secretin receptor family. These interactions have recently become an emerging topic, providing a new avenue for understanding how GPCR signaling is regulated. This review discusses our current state of knowledge about the role of GAGs in GPCR signaling and function.

Severe processing capacity limits for sub-lexical features of letter strings.

When reading, the visual system is confronted with many words simultaneously. How much of that information can a reader process at once? Previous studies demonstrated that low-level visual features of multiple words are processed in parallel, but lexical attributes are processed serially, for one word at a time. This implies that an internal bottleneck lies somewhere between early visual and lexical analysis. We used a dual-task behavioral paradigm to investigate whether this bottleneck lies at the stage of letter recognition or phonological decoding. On each trial, two letter strings were flashed briefly, one above and one below fixation, and then masked. In the letter identification experiment, participants indicated whether a vowel was present in a particular letter string. In the phonological decoding experiment, participants indicated whether the letter string was pronounceable. We compared accuracy in a focused attention condition, in which participants judged only one of the two strings, with accuracy in a divided attention condition, in which participants judged both strings independently. In both experiments, the cost of dividing attention was so large that it supported a serial model: participants were able to process only one letter string per trial. Furthermore, we found a stimulus processing trade-off that is characteristic of serial processing: When participants judged one string correctly, they were less likely to judge the other string correctly. Therefore, the bottleneck that constrains word recognition under these conditions arises at a sub-lexical level, perhaps due to a limit on the efficiency of letter recognition.

Posterolateral Corner of the Knee: An Update on Current Evaluation and Management Strategies.

Historically, the posterolateral corner (PLC) of the knee has been labelled as the "dark side" of the knee. The PLC is not a single structure but a confluence of multiple structures, including the lateral collateral ligament, popliteus muscle-tendon unit, and popliteofibular ligament. Understanding the individual components and their function is important to successfully identify these injuries. PLC injuries are commonly associated with cruciate injuries, and its early recognition is important to achieve successful outcomes. Injury to the PLC should be treated on a case-by-case basis, and an appropriate algorithm is required to manage them. Multiple surgical techniques ranging from primary repair to anatomic reconstruction have been reported in managing these injuries. We present the latest literature on the anatomy, biomechanics, clinical presentation, imaging, available techniques, and current management recommendations. There is a special focus on the pathoanatomy, which will help guide the treatment of these injuries.

Children with dyslexia show no deficit in exogenous spatial attention but show differences in visual encoding.

In the search for mechanisms that contribute to dyslexia, the term "attention" has been invoked to explain performance in a variety of tasks, creating confusion since all tasks do, indeed, demand "attention." Many studies lack an experimental manipulation of attention that would be necessary to determine its influence on task performance. Nonetheless, an emerging view is that children with dyslexia have an impairment in the exogenous (automatic/reflexive) orienting of spatial attention. Here we investigated the link between exogenous attention and reading ability by presenting exogenous spatial cues in the multi-letter processing task-a task relevant for reading. The task was gamified and administered online to a large sample of children (N = 187) between 6 and 17 years. Children with dyslexia performed worse overall at rapidly recognizing and reporting strings of letters. However, we found no evidence for a difference in the utilization of exogenous spatial cues, resolving two decades of ambiguity in the field. Previous studies that claimed otherwise may have failed to distinguish attention effects from overall task performance or found spurious group differences in small samples. RESEARCH HIGHLIGHTS: We manipulated exogenous visual spatial attention using pre-cues in a task that is relevant for reading and we see robust task effects of exogenous attention. We found no evidence for a deficit in utilizing exogenous spatial pre-cues in children with dyslexia. However, children with dyslexia showed reduced recognition ability for all letter positions. Children with dyslexia were just as likely to make letter transposition errors as typical readers.

Effects of Tourniquet Features on Application Processes.

BACKGROUND: We investigated emergency-use limb tourniquet design features effects on application processes (this paper) and times to complete those processes (companion paper). METHODS: Sixty-four appliers watched training videos and then each applied all eight tourniquets: Combat Application Tourniquet Generation 7 (CAT7), SOF™ Tactical Tourniquet-Wide Generation 3 (SOFTTW3), SOF™ Tactical Tourniquet-Wide Generation 5 (SOFTTW5), Tactical Mechanical Tourniquet (TMT), OMNA Marine Tourniquet (OMT), X8T tourniquet (X8T), Tactical Ratcheting Medical Tourniquet (Tac RMT), and RapidStop™ Tourniquet (RST). Application processes were scored from videos. RESULTS: Thirty-three appliers had no prior tourniquet experience. All 512 applications were placed proximal to the recipient's simulated distal thigh injury. Thirty-one appliers (13 with no experience) had 66 problem-free applications (18 by no experience appliers). Tightening-system mechanical problems were more frequent with windlass rod systems (26 losing hold of the rod, 27 redoing rod turns, and 58 struggling to secure the rod) versus ratchet systems (3 tooth skips and 16 advance failures). Thirty-five appliers (21 with no experience) had 68 applications (45 by no experience appliers) with an audible Doppler pulse when stating "Done"; causes involved premature stopping (53), inadequate strap pull (1 SOFTTW3, 1 RST), strap/redirect understanding problem (1 SOFTTW5, 1 X8T, 4 Tac RMT, 1 RST), tightening-system understanding problem (2 CAT7, 1 SOFTTW3, 1 TMT, 1 RST), and physical inability to secure (1 SOFTTW3). Fifty-three appliers (32 no experience) had 109 applications (64 by no experience appliers) not correctly secured. Six involved strap/redirect understanding problems: 4 Tac RMT, 1 X8T, 1 SOFTTW5; 103 involved improper securing of non-self-securing design features: 47 CAT7 (8 strap, 45 rod), 31 TMT (17 strap, 19 rod), 22 OMT (strap), and 3 SOFTTW3 (rod). CONCLUSION: Self-securing systems have process advantages. Because most emergent tourniquet recipients require transport, we believe tourniquet security is a critical design aspect. Decisions regarding tourniquet choices may become very different when both occlusion and tourniquet security are considered.

Effects of Tourniquet Features on Application Processes Times.

BACKGROUND: We investigated emergency-use limb tourniquet design features effects on application processes (companion paper) and times to complete those processes (this paper). METHODS: Sixty-four appliers watched training videos then each applied all eight tourniquets: Combat Application Tour- niquet Generation 7 (CAT7), SOF™ Tactical Tourniquet-Wide Generation 3 (SOFTTW3), SOF™ Tactical Tourniquet-Wide Generation 5 (SOFTTW5), Tactical Mechanical Tourniquet (TMT), OMNA Marine Tourniquet (OMT), X8T-Tourniquet (X8T), Tactical Ratcheting Medical Tourniquet (Tac RMT), and RapidStop Tourniquet (RST). Application processes times were captured from videos. RESULTS: From "Go" to "touch tightening system" was fastest with clips and self-securing redirect buckles and without strap/redirect application process problems (n, median seconds: CAT7 n=23, 26.89; SOFTTW3 n=11, 20.95; SOFTTW5 n=16, 20.53; TMT n=5, 26.61; OMT n=12, 25.94; X8T n=3, 18.44; Tac RMT n=15, 30.59; RST n=7, 22.80). From "touch tightening system" to "last occlusion" was fastest with windlass rod systems when there were no tightening system understanding or mechanical problems (seconds: CAT7 n=48, 4.21; SOFTTW3 n=47, 5.99; SOFTTW5 n=44, 4.65; TMT n=38, 6.21; OMT n=51, 6.22; X8T n=48, 7.59; Tac RMT n=52, 8.44; RST n=40, 8.02). For occluded, tightening system secure applications, from "touch tightening system" to "Done" was fastest with self-securing tightening systems tightening from a tight strap (occluded, secure time in seconds from a tight strap: CAT7 n=17, 14.47; SOFTTW3 n=22, 10.91; SOFTTW5 n=38, 9.19; TMT n=14, 11.42; OMT n=44, 7.01; X8T n=12 9.82; Tac RMT n=20, 6.45; RST n=23, 8.64). CONCLUSIONS: Suboptimal processes in- crease application times. Optimal design features for fast, occlusive, secure tourniquet applications are self-securing strap/ redirect systems with an easily identified and easily used clip and self-securing tightening systems.

Nonspecific membrane bilayer perturbations by ivermectin underlie SARS-CoV-2 in vitro activity.

Since it was proposed as a potential host-directed antiviral agent for SARS-CoV-2, the antiparasitic drug ivermectin has been investigated thoroughly in clinical trials, which have provided insufficient support for its clinical efficacy. To examine the potential for ivermectin to be repurposed as an antiviral agent, we therefore undertook a series of preclinical studies. Consistent with early reports, ivermectin decreased SARS-CoV-2 viral burden in in vitro models at low micromolar concentrations, five- to ten-fold higher than the reported toxic clinical concentration. At similar concentrations, ivermectin also decreased cell viability and increased biomarkers of cytotoxicity and apoptosis. Further mechanistic and profiling studies revealed that ivermectin nonspecifically perturbs membrane bilayers at the same concentrations where it decreases the SARS-CoV-2 viral burden, resulting in nonspecific modulation of membrane-based targets such as G-protein coupled receptors and ion channels. These results suggest that a primary molecular mechanism for the in vitro antiviral activity of ivermectin may be nonspecific membrane perturbation, indicating that ivermectin is unlikely to be translatable into a safe and effective antiviral agent. These results and experimental workflow provide a useful paradigm for performing preclinical studies on (pandemic-related) drug repurposing candidates.

The transposed word effect is consistent with serial word recognition and varies with reading speed.

The scientific study of reading has long been animated by questions of parallel vs. serial processing. Do readers recognize words serially, adding each one sequentially to a representation of the sentence structure? One fascinating phenomenon to emerge from this research is the transposed word effect: when asked to judge whether sentences are grammatical, readers often fail to notice grammatical errors caused by transposing two words. This effect could be evidence that readers recognize multiple words in parallel. Here we provide converging evidence that the transposed word effect is also consistent with serial processing because it occurs robustly when the words in each sentence are presented serially. We further investigated how the effect relates to individual differences in reading speed, to gaze fixation patterns, and to differences in difficulty across sentences. In a pretest, we first measured the natural English reading rate of 37 participants, which varied widely. In a subsequent grammatical decision task, we presented grammatical and ungrammatical sentences in two modes: one with all words presented simultaneously, and the other with single words presented sequentially at each participant's natural rate. Unlike prior studies that used a fixed sequential presentation rate, we found that the magnitude of the transposed word effect was at least as strong in the sequential presentation mode as in the simultaneous mode, for both error rates and response times. Moreover, faster readers were more likely to miss transpositions of words presented sequentially. We argue that these data favor a "noisy channel" model of comprehension in which skilled readers rely on prior knowledge to rapidly infer the meaning of sentences, allowing for apparent errors in spatial or temporal order, even when the individual words are recognized one at a time.

Use Of POCUS for the Paediatric Patient with an Undifferentiated Upper Limb Injury.

A 2-year-old girl presented to the Paediatric Emergency Department following an unwitnessed injury to her left arm while playing at nursery limiting further examination. On assessment she was reluctant to use her left arm and further examination was difficult. In cases of unwitnessed and undifferentiated elbow injuries point of care ultrasound (POCUS) can be used to evaluate for elbow joint effusion, fracture, or radial head subluxation, also known as nursemaid's elbow. Pulled elbow is a commonly encountered paediatric injury but based on the history and examination findings it may not always be obvious. We present an approach to the child with an undifferentiated elbow injury incorporating POCUS as a means of increasing the reliability of findings on clinical examination.

Rice-Body Synovitis, Foreign Body Reaction, and Rotator Cuff Failure After Subacromial Balloon Spacer Augmentation of a Rotator Cuff Repair: A Case Report.

CASE: A 66-year-old woman presented with shoulder pain and weakness 4 months after augmentation of a rotator cuff repair with a Stryker InSpace subacromial balloon spacer. A magnetic resonance imaging (MRI) demonstrated a failed rotator cuff repair, large effusion with rice bodies, synovitis, axillary lymphadenopathy, loose anchors, and erosive changes to the greater tuberosity. Arthroscopy revealed balloon fragmentation surrounded by diffusely hyperemic synovium without repairable cuff tissue. Final cultures proved negative for infection. Histologic evaluation revealed ulcerated synovium with diffuse chronic and focal acute inflammation. CONCLUSION: Despite promising early results, augmentation of a rotator cuff repair with a subacromial balloon spacer introduces a risk of inflammatory reaction that may mimic a deep infection and compromise rotator cuff healing.

Engaging in word recognition elicits highly specific modulations in visual cortex.

A person's cognitive state determines how their brain responds to visual stimuli. The most common such effect is a response enhancement when stimuli are task relevant and attended rather than ignored. In this fMRI study, we report a surprising twist on such attention effects in the visual word form area (VWFA), a region that plays a key role in reading. We presented participants with strings of letters and visually similar shapes, which were either relevant for a specific task (lexical decision or gap localization) or ignored (during a fixation dot color task). In the VWFA, the enhancement of responses to attended stimuli occurred only for letter strings, whereas non-letter shapes evoked smaller responses when attended than when ignored. The enhancement of VWFA activity was accompanied by strengthened functional connectivity with higher-level language regions. These task-dependent modulations of response magnitude and functional connectivity were specific to the VWFA and absent in the rest of visual cortex. We suggest that language regions send targeted excitatory feedback into the VWFA only when the observer is trying to read. This feedback enables the discrimination of familiar and nonsense words and is distinct from generic effects of visual attention.

Molecular Mechanisms of PTH/PTHrP Class B GPCR Signaling and Pharmacological Implications.

The classical paradigm of G protein-coupled receptor (GPCR) signaling via G proteins is grounded in a view that downstream responses are relatively transient and confined to the cell surface, but this notion has been revised in recent years following the identification of several receptors that engage in sustained signaling responses from subcellular compartments following internalization of the ligand-receptor complex. This phenomenon was initially discovered for the parathyroid hormone (PTH) type 1 receptor (PTH1R), a vital GPCR for maintaining normal calcium and phosphate levels in the body with the paradoxical ability to build or break down bone in response to PTH binding. The diverse biological processes regulated by this receptor are thought to depend on its capacity to mediate diverse modes of cyclic adenosine monophosphate (cAMP) signaling. These include transient signaling at the plasma membrane and sustained signaling from internalized PTH1R within early endosomes mediated by PTH. Here we discuss recent structural, cell signaling, and in vivo studies that unveil potential pharmacological outputs of the spatial versus temporal dimension of PTH1R signaling via cAMP. Notably, the combination of molecular dynamics simulations and elastic network model-based methods revealed how precise modulation of PTH signaling responses is achieved through structure-encoded allosteric coupling within the receptor and between the peptide hormone binding site and the G protein coupling interface. The implications of recent findings are now being explored for addressing key questions on how location bias in receptor signaling contributes to pharmacological functions, and how to drug a difficult target such as the PTH1R toward discovering nonpeptidic small molecule candidates for the treatment of metabolic bone and mineral diseases.

Botulinum toxin as adjunct therapy in surgical management of a periprosthetic scapular spine fracture: a case report.

Six months after undergoing reverse shoulder arthroplasty (RSA) a 73-year-old woman sustained a periprosthetic scapular spine fracture following a fall. She was treated with open reduction and internal fixation (ORIF), followed by botulinum toxin injection into the deltoid muscle to temporarily minimize strain at the fracture. Fracture union was achieved by 3 months, with excellent clinical function more than 1 year following fracture fixation and full resolution of deltoid function. Scapular spine fracture following RSA can be treated with ORIF and temporary deltoid paralysis using botulinum toxin in the immediate postoperative period to safely support fracture healing.

The Outcome of Hip Arthroscopy in the Setting of Lumbar Spine Disease Is Beneficial, Yet Limited: A Systematic Review of Existing Evidence.

PURPOSE: To compare hip arthroscopy outcomes in femoroacetabular impingement (FAI) patients with concurrent symptomatic lumbar spine disease to the outcomes of arthroscopic FAI patients without spine disease. METHODS: A systematic review was performed according to PRISMA guidelines via PubMed, Cochrane, Embase, and Google Scholar databases. Studies were valid for inclusion if they had an average follow-up ≥12 months and compared patient-reported outcome measures (PROMs) in hip arthroscopy patients with and without concurrent spinal disease. Data collected included study characteristics, patient demographics, follow-up intervals, surgical indications, spinal pathology, PROMs, and reoperation rates. RESULTS: Twelve studies were included in this systematic review. 3,107 patients who underwent hip arthroscopy were evaluated: 1,056 with coexisting lumbar spine disease (spine cohort) and 2,051 control subjects without spine disease (control cohort). The average follow-up period was 24 months. Across included studies, there were 35 instances wherein postoperative PROM scores reported by each cohort were compared. In all 35 instances, the spine cohort reported inferior postoperative PROM scores with the difference being significant (P < .05) on 23 PROMs. Collectively, 23 cases were available contrasting the proportion of each cohort to achieve the minimal clinically important difference (MCID). In 22 (95.65%) of these cases, the spine cohort achieved the MCID at a lower rate than the control cohort. There were 14 PROMs, wherein intragroup analyses were reported that compared the preoperative and postoperative score reported by the spine cohort. On all 14 PROMs, the spine cohort reported significant (P < .05) improvement after arthroscopic intervention. CONCLUSION: FAI patients with coexisting lumbar spine pathology experience significant improvement from baseline state after arthroscopic intervention. However, the postoperative outcomes reported are inferior, and the improvement from arthroscopy was limited when compared to surgical control subjects with FAI and normal spinal anatomy. LEVEL OF EVIDENCE: Level IV: systematic review of Level II, III, and IV studies.

Arthroscopic Subdeltoid Transfer of the Long Head of the Biceps Tendon to the Conjoint Tendon.

Surgical intervention is often recommended for refractory pathology affecting the biceps-labrum complex. Tenodesis of the long head of the biceps tendon (LHBT) is a widely accepted treatment modality; however, the optimal technique remains elusive. Arthroscopic subdeltoid transfer of the LHBT to the conjoint tendon, as described in this technical note, continues to demonstrate excellent clinical results. Its advantages include soft tissue-to-soft tissue healing, an advantageous biomechanical construct, and comprehensive evaluation and decompression of the LHBT including the extra-articular bicipital tunnel. The primary limitation of this procedure is the perceived learning curve for safe navigation within the subdeltoid space.

Medial Ulnar Collateral Ligament Injuries in Contact Athletes.

PURPOSE OF REVIEW: The purpose of this article is to review medial ulnar collateral ligament (UCL) injuries in contact athletes. UCL injuries in overhead throwing athletes are typically chronic attenuation due to repetitive valgus stress on the elbow during the throwing motion. As such, UCL reconstruction is commonly performed for these athletes. In contrast, UCL injuries in contact athletes are usually acute ligament tears or avulsions of a ligament with otherwise normal tissue. Nonoperative treatment is typically the first-line treatment for partial injuries. UCL repair may work well for acute complete injuries and may avoid the donor site morbidity of UCL reconstruction. RECENT FINDINGS: Most of the literature regarding UCL injuries have been performed in baseball players. Historically, UCL repair has had poor outcomes in baseball players due to the chronic ligament attenuation. Therefore, much of the recent literature has focused on outcomes of UCL reconstruction, which are generally excellent. However, there is a paucity of literature studying outcomes of UCL injuries in contact athletes and those studying UCL repair. One recent study looked at a new technique for UCL repair with collagen-coated fiber tape augmentation in baseball players and found good short-term outcomes. UCL injuries in contact athletes occur typically as acute tears or avulsions. While UCL reconstruction has typically been recommended as the accepted treatment for UCL tears that require operative treatment, UCL repair may be a good alternative in contact athletes.

Biased GPCR signaling by the native parathyroid hormone-related protein 1 to 141 relative to its N-terminal fragment 1 to 36.

The parathyroid hormone (PTH)-related protein (PTHrP) is indispensable for the development of mammary glands, placental calcium ion transport, tooth eruption, bone formation and bone remodeling, and causes hypercalcemia in patients with malignancy. Although mature forms of PTHrP in the body consist of splice variants of 139, 141, and 173 amino acids, our current understanding on how endogenous PTHrP transduces signals through its cognate G-protein coupled receptor (GPCR), the PTH type 1 receptor (PTHR), is largely derived from studies done with its N-terminal fragment, PTHrP1-36. Here, we demonstrate using various fluorescence imaging approaches at the single cell level to measure kinetics of (i) receptor activation, (ii) receptor signaling via Gs and Gq, and (iii) receptor internalization and recycling that the native PTHrP1-141 displays biased agonist signaling properties that are not mimicked by PTHrP1-36. Although PTHrP1-36 induces transient cAMP production, acute intracellular Ca2+ (iCa2+) release and ß-arrestin recruitment mediated by ligand-PTHR interactions at the plasma membrane, PTHrP1-141 triggers sustained cAMP signaling from the plasma membrane and fails to stimulate iCa2+ release and recruit ß-arrestin. Furthermore, we show that the molecular basis for biased signaling differences between PTHrP1-36 and properties of native PTHrP1-141 are caused by the stabilization of a singular PTHR conformation and PTHrP1-141 sensitivity to heparin, a sulfated glycosaminoglycan. Taken together, our results contribute to a better understanding of the biased signaling process of a native protein hormone acting in conjunction with a GPCR.

Oculomotor freezing indicates conscious detection free of decision bias.

The appearance of a salient stimulus rapidly and automatically inhibits saccadic eye movements. Curiously, this "oculomotor freezing" response is triggered only by stimuli that the observer reports seeing. It remains unknown, however, whether oculomotor freezing is linked to the observer's sensory experience or their decision that a stimulus was present. To dissociate between these possibilities, we manipulated decision criterion via monetary payoffs and stimulus probability in a detection task. These manipulations greatly shifted observers' decision criteria but did not affect the degree to which microsaccades were inhibited by stimulus presence. Moreover, the link between oculomotor freezing and explicit reports of stimulus presence was stronger when the criterion was conservative rather than liberal. We conclude that the sensory threshold for oculomotor freezing is independent of decision bias. Provided that conscious experience is also unaffected by such bias, oculomotor freezing is an implicit indicator of sensory awareness.NEW & NOTEWORTHY Sometimes a visual stimulus reaches awareness, and sometimes it does not. To understand why, we need objective, bias-free measures of awareness. We discovered that a reflexive freezing of small eye movements indicates when an observer detects a stimulus. Furthermore, when we biased observers' decisions to report seeing the stimulus, the oculomotor response was unaltered. This suggests that the threshold for conscious perception is independent of the decision criterion and is revealed by oculomotor freezing.

Journey around the Notch: A Systematic Review on the History of ACL Reconstruction in the United States.

The evolution of anterior cruciate ligament (ACL) surgery, seemingly circular at times, informs and provides context for past and current controversies in ACL management. The purpose of this systematic review is to objectively summarize the historical course of ACL reconstruction and repair in the United States over the last 40 years. Femoral tunnel drilling and graft selection have evolved dramatically over the last few decades. An initial focus on restoring ACL anatomy was for a period sacrificed for decreased operative morbidity. However, recent developments in operative techniques aim to restore ACL anatomy while also achieving minimal operative morbidity. Despite this historically iterative process, there remains no perfect choice for the treatment of ACL tears. Continued research on ACL repair, anatomic graft placement, graft choice, and augmentation will help our patients over the next generation.