Repair of bucket handle meniscus tears improves patient outcomes versus partial meniscectomy at the time of ACL reconstruction.

Purpose: The aim of this study was to examine demographic and surgical factors that influence patient-reported knee function in patients who undergo anterior crucial ligament reconstruction (ACLR) with concurrent bucket-handle meniscal tear (BHMT) procedures. We hypothesized that repair of BHMT in the setting of concomitant ACLR and shorter time from injury to surgery would lead to improved patient-reported outcomes. Methods: Forty-one patients (mean age: 28.0 ± 9.8 years, 72% male) with BHMT at the time of ACLR completed the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) via online survey at an average of 15.2 months postop. Patient demographics and surgical characteristics, including time from injury to surgery, were compared between repair (n = 22) and meniscectomy (n = 19) groups using one-way analysis of variances; distributions of sex, graft source, BHMT compartment and zone were compared between groups using χ 2 tests. The association between IKDC-SKF score, demographics and surgical characteristics was evaluated using multivariable linear regression. A priori alpha level was p < 0.05. Results: Meniscal repair and meniscectomy groups differed based on graft source and BHMT zone but not IKDC-SKF score (p = 0.085). Patients undergoing ACLR with autograft (p = 0.003) and with red-red zone BHMT (p < 0.001) more often underwent meniscal repair. The regression model demonstrated longer time from injury to surgery (p = 0.049), red-red tear zone (p = 0.04) and meniscectomy (p = 0.008); these were predictive of poorer IKDC-SKF scores. Conclusion: BHMT repair was more likely performed in ACL autograft and on red-red zone tears. Longer time from injury to surgery is an indicator of poorer IKDC-SKF score, as this may increase the risk of concomitant pathologies. White-white zone BHMTs are associated with better IKDC-SKF scores than red-red zone BHMTs, which may be due to the smaller volume of tissue removed during meniscectomy of white-white zone tears and the avoidance of iatrogenic complications of meniscal repair. Level of Evidence: Level III, therapeutic study.

The Effect of Greater Area Deprivation and Medicaid Insurance Status on Timing of Care and Rate of Reinjury After Anterior Cruciate Ligament Reconstruction.

Background: Lower socioeconomic status and public insurance lead to a longer delay to surgery and a higher likelihood of concomitant pathology before undergoing anterior cruciate ligament reconstruction (ACLR). However, few studies have examined the influence of community deprivation on ACLR timing and outcomes. Purpose/Hypothesis: The primary aim of this study was to define the effect of the area deprivation index (ADI) and insurance classification on access to orthopaedic care after an ACL rupture, and the secondary aim was to determine whether these variables were associated with a second ACL injury after primary ACLR. It was hypothesized that patients with a greater national ADI percentile and Medicaid insurance would experience longer delays to care and an increased risk of reinjury after ACLR. Study Design: Cohort study; Level of evidence, 3. Methods: A retrospective study was performed to evaluate patients undergoing primary ACLR between 2016 and 2019. The national ADI percentile was obtained utilizing the Neighborhood Atlas website. The relationship between national ADI percentile and care characteristics (eg, time to specialized care) was investigated using the Spearman rho correlation coefficient (r). The association between patient and care characteristics and second ACL injury after the index procedure (ie, graft rerupture or contralateral ACL rupture) was investigated using binary logistic regression. Results: A total of 197 patients met the inclusion criteria. Longer times from injury to surgery (r = 0.238; P < .001) and from specialized care to surgery (r = 0.217; P = .002) were associated with a greater national ADI percentile. The second injury group reported significantly greater national ADI (P = .026) and included a greater percentage of patients with Medicaid insurance (31.3%) compared with the no second injury group. Patients experienced 5.1% greater odds of a second ACL injury for each additional month between evaluation and surgery. Conclusion: Greater national ADI percentile and Medicaid insurance status were associated with adverse ACLR timing and outcomes. Patients with a greater national ADI percentile took significantly longer to obtain surgery after ACL injury. Those who sustained a second ACL injury after ACLR had an overall higher mean national ADI percentile and included a greater proportion of patients with Medicaid compared with those who did not sustain a second ACL injury. Future studies should critically investigate the underlying factors of these associations to reach equity in orthopaedic care.

Dyslipidaemia is associated with Cutibacterium acnes hip and knee prosthetic joint infection.

PURPOSE: Optimization of medical factors including diabetes and obesity is a cornerstone in the prevention of prosthetic joint infection (PJI). Dyslipidaemia is another component of metabolic syndrome which has not been thoroughly investigated as an individual, modifiable risk factor. This study examined the association of dyslipidaemia with PJI caused by the lipophilic microbe Cutibacterium acnes (C. acnes). METHODS: A retrospective chart review examined patients with positive C. acnes culture at hip or knee arthroplasty explantation. A control group with methicillin-sensitive Staphylococcus aureus (MSSA) positive cultures at explantation was matched for age, sex, and surgical site, as well as a second control group with no infection. A total of 80 patients were included, 16 with C. acnes, 32 with MSSA, and 32 with no infection. All patients had a lipid panel performed within one year of surgery. Lipid values and categories were compared using multinomial logistic regressions. RESULTS: High or borderline triglycerides (TG) (relative risk ratio (RRR) = 0.13; P = 0.013) and low high-density lipoprotein (HDL) (RRR = 0.13; P = 0.025) were significantly associated with C. acnes PJI compared to MSSA-PJI. High or borderline TG (RRR = 0.21; P = 0.041) and low HDL (RRR = 0.17; P = 0.043) were also associated with a greater probability of C. acnes infection compared to no infection. CONCLUSIONS: The presence of elevated TG and low HDL were both associated at a statistically significant level with C. acnes hip or knee PJI compared to controls with either MSSA PJI or no infection. This may represent a specific risk factor for C. acnes PJI that is modifiable.

Machine learning classifiers for electrode selection in the design of closed-loop neuromodulation devices for episodic memory improvement.

Successful neuromodulation approaches to alter episodic memory require closed-loop stimulation predicated on the effective classification of brain states. The practical implementation of such strategies requires prior decisions regarding electrode implantation locations. Using a data-driven approach, we employ support vector machine (SVM) classifiers to identify high-yield brain targets on a large data set of 75 human intracranial electroencephalogram subjects performing the free recall (FR) task. Further, we address whether the conserved brain regions provide effective classification in an alternate (associative) memory paradigm along with FR, as well as testing unsupervised classification methods that may be a useful adjunct to clinical device implementation. Finally, we use random forest models to classify functional brain states, differentiating encoding versus retrieval versus non-memory behavior such as rest and mathematical processing. We then test how regions that exhibit good classification for the likelihood of recall success in the SVM models overlap with regions that differentiate functional brain states in the random forest models. Finally, we lay out how these data may be used in the design of neuromodulation devices.

A Control-Theoretical System for Modulating Hippocampal Gamma Oscillations Using Stimulation of the Posterior Cingulate Cortex.

Closed-loop stimulation for targeted modulation of brain signals has emerged as a promising strategy for episodic memory restoration. In parallel, closed-loop neuromodulation strategies have been applied to treat brain conditions including drug-resistant depression, Parkinson's Disease, and epilepsy. In this study, we seek to apply control theoretical principles to achieve closed loop modulation of hippocampal oscillatory activity. We focus on hippocampal gamma power, a signal with an established association for episodic memory processing, which may be a promising 'biomarker' for the modulation of memory performance. To develop a closed-loop stimulation paradigm that effectively modulates hippocampal gamma power, we use a novel data-set in which open-loop stimulation was applied to the posterior cingulate cortex and hippocampal gamma power was recorded during the encoding of episodic memories. The dataset was used to design and evaluate a linear quadratic integral (LQI) servo-controller in order to determine its viability for in-vivo use. In our simulation framework, we demonstrate that applying an LQI servo controller based on an autoregressive with exogenous input (ARX) plant model achieves effective control of hippocampal gamma power in 15 out of 17 experimental subjects. We demonstrate that we are able to modulate gamma power using stimulation thresholds that are physiologically safe and on time scales that are reasonable for application in a clinical system. We outline further experimentation to test our proposed system and compare our findings to emerging closed-loop neuromodulation strategies.

No Difference in Complications Between Elbow Ulnar Collateral Ligament Reconstruction With the Docking and Modified Jobe Techniques: A Systematic Review and Meta-analysis.

BACKGROUND: The most commonly used techniques for elbow ulnar collateral ligament reconstruction (UCLR) are the docking and modified Jobe figure-of-8 techniques. Previous literature has suggested that UCLR with the docking technique is associated with fewer complications; however, these studies included results from the original classic Jobe technique without controlling for the effects of flexor pronator mass (FPM) detachment and routine submuscular ulnar nerve transposition (UNT). PURPOSE/HYPOTHESIS: This study sought to compare the rates of complications and subsequent unplanned surgical procedures between the docking and figure-of-8 techniques. We hypothesized that there would be no significant difference in the rates of complications or subsequent unplanned surgical procedures between the techniques when the FPM was preserved and no routine submuscular UNT was performed. STUDY DESIGN: Systematic review and meta-analysis; Level of evidence, 4. METHODS: This study was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A series of mixed-effects multivariate metaregression models were implemented using the restricted maximum likelihood method. Complications and subsequent unplanned surgical procedures were modeled as Freeman-Tukey transformed incidence rates for variance stabilization, and nerve-specific complications were assessed as the Freeman-Tukey transformed proportion of cases, with back-transformation to estimate summary effects. RESULTS: There were 19 studies eligible for qualitative analysis, consisting of 1788 cases of UCLR (303 docking, 1485 figure-of-8), 18 of which were suitable for quantitative analysis (1769 cases; 291 docking, 1478 figure-of-8). A total of 338 complications were reported (17 for docking, 321 for figure-of-8), the majority of which were nerve related. Additionally, a total of 75 subsequent unplanned surgical procedures were related to the index UCLR procedure. There was no significant difference in the rate of complications (P = .146) or proportion of cases with nerve-specific complications (P = .127) between the docking and figure-of-8 techniques when controlling for FPM preservation versus detachment with submuscular UNT. FPM detachment with submuscular UNT was independently associated with a significantly higher proportion of postoperative nerve-related complications (P = .004). There was also no significant difference in the rates of subsequent unplanned surgical procedures between the docking and figure-of-8 techniques (P = .961), although FPM detachment with routine submuscular UNT was independently associated with a significantly higher incidence of subsequent unplanned surgical procedures. CONCLUSION: The results of this study demonstrate no significant difference in the rates of complications or subsequent unplanned surgical procedures between the figure-of-8 and docking techniques for UCLR when controlling for FPM preservation versus detachment with submuscular UNT. With modern muscle-sparing approaches and avoiding submuscular UNT, the modified Jobe technique does not differ significantly from the docking technique in terms of complication rates, proportions of cases with nerve-specific complications, or rates of subsequent unplanned surgical procedures.

Treatment modalities and outcomes following acetabular fractures in the elderly: a systematic review.

PURPOSE: The treatment of geriatric acetabular fractures remains controversial. Treatment options include nonoperative management, open reduction and internal fixation (ORIF), total hip arthroplasty (THA) with or without internal fixation, and closed reduction with percutaneous pinning (CRPP). There is currently no consensus on the optimal treatment strategy for geriatric patients with acetabular fractures. The purpose of this study is to compare adverse event rates, functional and radiographic outcomes, and intraoperative results between the various treatment modalities in order to help guide surgical decision making. METHODS: We performed a systematic review (registration number CRD42019124624) of observational and comparative studies including patients aged ≥ 55 with acetabular fractures. RESULTS: Thirty-eight studies including 3,928 patients with a mean age of 72.6 years (range 55-99 years) and a mean follow-up duration of 29.4 months met our eligibility criteria. The pooled mortality rate of all patients was 21.6% (95% confidence interval [CI] 20.9-22.4%) with a mean time to mortality of 12.6 months, and the pooled non-fatal complication rate was 24.7% (95% CI 23.9-25.5%). Patients treated with ORIF had a significantly higher non-fatal complication rate than those treated with ORIF + THA, THA alone, CRPP, or nonoperative management (odds ratios [ORs] 1.87, 2.24, 2.15, and 4.48, respectively; p < 0.01). Patients that underwent ORIF were significantly less likely to undergo subsequent THA than these treated with CRPP (OR 0.49, 95% CI 0.32-0.77) but were more likely to require THA than patients treated nonoperatively (OR 6.81, 95% CI 4.63-10.02). CONCLUSION: Elderly patients with acetabular fractures tend to have favorable functional outcomes but suffer from high rates of mortality and complications. In patients treated with internal or percutaneous fixation, there was a high rate of conversion to THA. When determining surgical treatment in this population, THA alone or concurrent with ORIF should be considered given the significantly lower rate of non-fatal complications and similar mortality rate. Nonoperative management remains a viable option and was associated with the lowest non-fatal complication rate. LEVEL OF EVIDENCE: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Distinct neurophysiological correlates of the fMRI BOLD signal in the hippocampus and neocortex.

Functional magnetic resonance imaging (fMRI) is among the foremost methods for mapping human brain function but provides only an indirect measure of underlying neural activity. Recent findings suggest that the neurophysiological correlates of the fMRI blood-oxygen-level-dependent (BOLD) signal might be regionally specific. We examined the neurophysiological correlates of the fMRI BOLD signal in the hippocampus and neocortex, where differences in neural architecture might result in a different relationship between the respective signals. Fifteen human neurosurgical patients (10 female, 5 male) implanted with depth electrodes performed a verbal free recall task while electrophysiological activity was recorded simultaneously from hippocampal and neocortical sites. The same patients subsequently performed a similar version of the task during a later fMRI session. Subsequent memory effects (SMEs) were computed for both imaging modalities as patterns of encoding-related brain activity predictive of later free recall. Linear mixed-effects modelling revealed that the relationship between BOLD and gamma-band SMEs was moderated by the lobar location of the recording site. BOLD and high gamma (70-150 Hz) SMEs positively covaried across much of the neocortex. This relationship was reversed in the hippocampus, where a negative correlation between BOLD and high gamma SMEs was evident. We also observed a negative relationship between BOLD and low gamma (30-70 Hz) SMEs in the medial temporal lobe more broadly. These results suggest that the neurophysiological correlates of the BOLD signal in the hippocampus differ from those observed in the neocortex.Significance Statement:The blood-oxygen-level-dependent (BOLD) signal forms the basis of fMRI but provides only an indirect measure of neural activity. Task-related modulation of BOLD signals are typically equated with changes in gamma-band activity; however, relevant empirical evidence comes largely from the neocortex. We examined neurophysiological correlates of the BOLD signal in the hippocampus, where the differing neural architecture might result in a different relationship between the respective signals. We identified a positive relationship between encoding-related changes in BOLD and gamma-band activity in frontal and parietal cortex. This effect was reversed in the hippocampus, where BOLD and gamma-band effects negatively covaried. These results suggest regional variability in the transfer function between neural activity and the BOLD signal in the hippocampus and neocortex.

Player age and initial helmet contact among American football players.

OBJECTIVE: Concussions and chronic traumatic encephalopathy (CTE) related to professional football has received much attention within emergency care and sports medicine. Research suggests that some of this may be due to a greater likelihood of initial helmet contact (IHC), however this association has not been studied across all age groups. This study aims to investigate the association between player age and IHC in American football. METHODS: Retrospective review of championship games between 2016 and 2018 at 6 levels of amateur tackle football as well as the National Football League (NFL). Trained raters classified plays as IHC using pre-specified criteria. A priori power analysis established the requisite impacts needed to establish non-inferiority of the incidence rate of IHC across the levels of play. RESULTS: Thirty-seven games representing 2912 hits were rated. The overall incidence of IHC was 16% across all groups, ranging from 12.6% to 18.9%. All but 2 of the non-NFL divisions had a statistically reduced risk of IHC when compared with the NFL, with relative risk ratios ranging from 0.55-0.92. IHC initiated by defensive participants were twice as high as offensive participants (RR 2.04, p < 0.01) while 6% [95% CI 5.4-7.2] of all hits were helmet-on-helmet contact. CONCLUSIONS: There is a high rate of IHC with a lower relative risk of IHC at most levels of play compared to the NFL. Further research is necessary to determine the impact of IHC; the high rates across all age groups suggests an important role for education and prevention.

Cross-regional phase amplitude coupling supports the encoding of episodic memories.

Phase amplitude coupling (PAC) between theta and gamma oscillations represents a key neurophysiological mechanism that promotes the temporal organization of oscillatory activity. For this reason, PAC has been implicated in item/context integration for episodic processes, including coordinating activity across multiple cortical regions. While data in humans has focused principally on PAC within a single brain region, data in rodents has revealed evidence that the phase of the hippocampal theta oscillation modulates gamma oscillations in the cortex (and vice versa). This pattern, termed cross-regional PAC (xPAC), has not previously been observed in human subjects engaged in mnemonic processing. We use a unique dataset with intracranial electrodes inserted simultaneously into the hippocampus and seven cortical regions across 40 human subjects to (1) test for the presence of significant cross-regional PAC (xPAC), (2) to establish that the magnitude of xPAC predicts memory encoding success, (3) to describe specific frequencies within the broad 2-9 Hz theta range that govern hippocampal-cortical interactions in xPAC, and (4) compare anterior versus posterior hippocampal xPAC patterns. We find that strong functional xPAC occurs principally between the hippocampus and other mesial temporal structures, namely entorhinal and parahippocampal cortices, and that xPAC is overall stronger for posterior hippocampal connections. We also show that our results are not confounded by alternative factors such as inter-regional phase synchrony, local PAC occurring within cortical regions, or artifactual theta oscillatory waveforms.