Professional baseball pitchers produce similar ball velocity and kinematics when pitching from the wind-up and stretch deliveries: a biomechanical analysis.

Historically, the wind-up delivery is considered a more biomechanically advantageous pitching motion compared to the stretch. Recently, some pitchers have shifted to pitching exclusively from the stretch regardless of the game situation. The goal of this study was to compare temporal, kinematic and kinetic variables between the wind-up and stretch deliveries. Professional pitchers (n = 52, 189.1 ± 4.8 cm, 92.8 ± 8.4 kg) threw fastballs evaluated by 3D-motion capture (480 Hz) from both the wind-up and stretch deliveries. Within a pitcher, there was no significant difference in ball velocity between the two deliveries (p = 0.15). The stretch delivery was significantly quicker to ball release at toe off 2 (p < 0.001) (the last frame the pitcher's foot contacts the ground before progressing to maximum knee height) and maximum knee height (p < 0.001). The majority of differences occurred prior to foot contact. The wind-up delivery produced greater maximum shoulder external rotation (p < 0.001) and lead knee flexion at ball release (p < 0.001). Pitching from the stretch incurred greater shoulder superior force (p < 0.001). It remains unknown if this is clinically significant as pooled means show only a 2% difference. Therefore, pitching a fastball from either the wind-up or stretch delivery provides comparable mechanics and throwing arm load with likely comparable risk of injury.

Trends in Payments for Facility and Surgeon Professional Fees for Shoulder Surgeries Performed at Ambulatory Surgery Centers.

BACKGROUND: It has previously been demonstrated that utilization of ambulatory surgery centers (ASCs) results in cost savings and improved outcomes. Despite these benefits, Medicare reimbursement for professional fees at ASCs are decreasing over time. In this study, we sought to analyze the discrepancy between facility fee and professional fee reimbursements for ASCs by Medicare for common shoulder procedures over time. We hypothesized that professional fees for shoulder procedures would decrease over the study period while facility fees kept pace with inflation. METHODS: Current Procedural Terminology (CPT) codes were used to identify shoulder specific procedures approved for ASCs by Centers for Medicare and Medicaid Services (CMS). Procedures were grouped into arthroscopic and open categories. Publicly available data from CMS was accessed via the Medicare Physician Fee Schedule Lookup Tool and used to determine professional fee payments from 2018-2024. Additionally, Medicare ASC Payment Rates files were accessed to determine facility fee reimbursements to ASCs from 2018-2024. Descriptive statistics were used to calculate means and percent change over time. Compound annual growth rates (CAGR) were calculated and discrepancies in inflation were corrected for using the Consumer Price Index. The Benjamini and Hochberg method was used to correct P values in the setting of multiple comparisons. RESULTS: A total of 33 common shoulder procedures were included for analysis (10 arthroscopic codes and 23 open codes). Reimbursements for facility fees have remained significantly higher than corresponding professional fees for both open and arthroscopic procedures (p<0.01). On average, facility fee reimbursements for common shoulder surgeries have risen on an annual basis in a manner consistent with inflation (p=0.838). However, professional fees for these procedures have experienced a nearly uniform decline over the study period both nominally and in inflation-adjusted dollars (p=0.064 and p=0.005, respectively). CONCLUSION: Facility fee payments for outpatient approved shoulder surgeries have matched or outpaced inflation. Over the same time period, professional fee reimbursements for surgeons are consistently decreasing, both in absolute and inflation-adjusted dollars. Reform to the physician fee schedule is necessary to ensure that Medicare patients retain access to high-quality physician care.

A Prospective, Randomized, Double-Blind Clinical Trial to Investigate the Efficacy of Autologous Bone Marrow Aspirate Concentrate During Arthroscopic Meniscectomy in Patients With Early Knee Osteoarthritis.

BACKGROUND: Despite being recognized as a safe procedure with minimal reported complications, injecting autologous bone marrow aspirate concentrate (BMAC) as an adjuvant to arthroscopic partial meniscectomy (APM) for symptomatic patients with meniscal tears and concomitant knee osteoarthritis (OA) has not been studied in randomized controlled trials. PURPOSE: To compare patient-reported outcome measure (PROM) scores and radiographic outcomes in symptomatic patients with meniscal tears and concomitant mild knee OA who underwent APM with and without an autologous BMAC injection administered at the time of surgery. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: Enrolled patients aged ≥18 years determined to have a symptomatic meniscal tear with concomitant mild knee OA suitable for APM and meeting inclusion and exclusion criteria were randomized into 2 groups: BMAC and control (no BMAC). The primary endpoint of the study was the International Knee Documentation Committee (IKDC) score at 1 year postoperatively. Secondary endpoints included radiographic outcomes (Kellgren-Lawrence grade) at 1 year postoperatively and various PROM scores, including those for the IKDC, Knee injury and Osteoarthritis Outcome Score (KOOS), visual analog scale, and Veterans RAND 12-Item Health Survey, at 3 months, 6 months, 1 year, and 2 years after meniscectomy. RESULTS: Of the 95 enrolled patients, 83 (87.4%) were included for final analysis. No significant differences were found between the groups with regard to patient characteristics, intraoperative variables, concomitant procedures, preoperative PROM scores, or preoperative radiographic findings. At 1 year postoperatively, the BMAC group failed to demonstrate significantly better IKDC scores (P = .687) or radiographic outcomes (P > .05 for all radiographic measures) compared with the control group. Secondary PROM scores also did not significantly differ between the groups (P > .05 for all PROMs). However, there were higher achievement rates of the minimal clinically important difference for the KOOS Sport (100.0% vs 80.0%, respectively; P = .023) and KOOS Symptoms (92.3% vs 68.0%, respectively; P = .038) at 1 year postoperatively in the BMAC group than in the control group. All PROMs, excluding the VR-12 mental score, showed significant improvements compared with baseline at all postoperative time points for both the BMAC and control groups. CONCLUSION: The addition of an autologous BMAC injection during APM did not result in significant changes in IKDC scores or radiographic outcomes at the 1-year postoperative mark. Secondary PROM scores were generally comparable between the 2 groups, but there was higher minimal clinically important difference achievement for the KOOS Sport and KOOS Symptoms at 1 year postoperatively in the BMAC group. In patients with symptoms consistent with a meniscal tear who had concomitant mild OA, the addition of BMAC to arthroscopic debridement did not affect the outcome. REGISTRATION: NCT02582489 (ClinicalTrials.gov).

The incidence and decompression rates of median and ulnar neuropathies following shoulder surgery.

Background: Upper extremity peripheral neuropathy is a known, but uncommon complication that can occur after shoulder surgery. The incidence rate is well documented, and most of these cases historically have been treated conservatively. However, we hypothesize peripheral compression neuropathy requires a much higher need for surgical decompression than originally reported. The purpose of this study was to evaluate the incidence, decompression rates, and prognostic factors for developing median and ulnar neuropathies following shoulder surgery. Methods: A retrospective chart review was performed examining patients who underwent open and arthroscopic shoulder surgery from a multisurgeon, single-institution database. Perioperative data and functional outcomes were recorded. Symptom resolution was assessed with both conservative and surgical management of compression peripheral neuropathy. Further analysis was made to compare open and arthroscopic procedures, the type of neuropathy developed, and electromyographic (EMG) severity. Results: The incidence rates of compression peripheral neuropathy following open arthroplasty and arthroscopic procedures was 1.80% (31/1722) and 0.54% (44/8150), respectively. 73.33% (55/75) of patients developed ipsilateral disease, while 20.00% (15/75) of patients had bilateral disease. Amongst the 75 included patients, there were 99 cases of neuropathy. Carpal tunnel syndrome was more common than cubital tunnel syndrome, comprising 61.61% (61/99) cases of neuropathy. 12.00% (9/75) of patients developed both carpal tunnel syndrome and cubital tunnel syndrome. Four patients were lost to follow-up. Decompression surgery was performed for 36.84% (35/95) cases of neuropathy with >90% obtaining symptom resolution with surgery. 63.16% (60/95) cases of neuropathy were managed conservatively, 71.67% (43/60) of which had persistent symptoms. When comparing arthroscopic versus open procedures, patients who underwent open procedures were significantly older (68.62 vs. 49.78 years, P < .001) and developed peripheral neuropathy significantly faster after the index procedure (87.24 vs. 125.58 days, P = .008). EMG severity did not correlate with decompression rates or symptom resolution. There were no differences in the subgroup analyses between beach chair and lateral positioning in regard to the type of neuropathy, laterality of symptoms, and/or treatment received. Conclusion: The overall incidence of peripheral neuropathy after shoulder surgery was 0.76% (75/9872). The development of peripheral neuropathy is multifactorial, with older patients undergoing open arthroplasty more at risk. Neuropathy symptoms were refractory to conservative management despite the type of shoulder surgery, type of neuropathy, or EMG severity. Decompression consistently led to resolution of symptoms.

ACL Reconstruction in Patients Over Fifty Years of Age Results in Improvements in Functional Outcomes and Broad Complication Rates: A Systematic Review.

PURPOSE: To assess the patient-reported outcomes measures (PROMs), functional knee measures, and incidence of complications in patients aged 50 and older undergoing anterior cruciate ligament reconstruction (ACLR). METHODS: A literature search was conducted across PubMed, Embase, and Scopus databases, spanning from their inception to November 2023, in accordance with the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Inclusion criteria consisted of clinical studies reporting PROMs, measures of knee stability, and complication rates, following ACLR in patients aged ≥ 50 with minimum 2 year follow-up. The Methodological Index for Non-Randomized Studies (MINORS) criteria was used to assess study quality. Primary outcome measures consisted of changes PROMs and complication rates following ACLR. RESULTS: A total of 17 studies, consisting of 1,163 patients undergoing ACLR were identified. Autografts were utilized in 90.3% of patients, compared to 9.7% of patients treated using allografts. At minimum 24-month follow-up, the mean International Knee Documentation Score (IKDC) ranged from 67.4 to 92.96, while mean Lysholm scores ranged from 84.4 to 94.8, and mean Tegner scores ranged from 0.3 to 5.4. The mean side to side difference at final follow-up ranged from 1.2 to 2.4mm while the rates of recurrent instability ranged from 0 to 18%. Complications and revisions ranged from 0% to 40.4% and 0% to 37.5% of cases, with the highest rates observed in studies noting a high incidence of intraoperative cartilage lesions. CONCLUSION: Anterior cruciate ligament reconstruction in patients above the age of 50 results in favorable IKDC, Lysholm and Tegner activity scores and improvements in functional knee measures. However, a wide range of reoperation and complications are reported, attributed to varying levels of chondral injury and osteoarthritis which warrant consideration when discussing expectations in patients 50 and above undergoing ACLR. LEVEL OF EVIDENCE: IV, Systematic Review of Level II-IV studies.

Anterior Cruciate Ligament Repair Results in Similar Patient Reported Outcome Measures as Anterior Cruciate Ligament Reconstruction: A Systematic Review of Prospective Comparative Studies.

PURPOSE: To investigate the patient-reported outcomes (PROs), knee stability, and complications in prospective comparative studies of patients undergoing augmented anterior cruciate ligament (ACL) repair compared to ACL reconstruction (ACLR). METHODS: A literature search was performed according to the 2020 PRISMA guidelines. Human clinical studies of level I-II evidence comparing PROs, knee stability and complications following ACL repair and reconstruction were included, and a qualitative analysis was performed. Excluded studies included those lacking reporting outcomes, studies that performed open ACLR or repair, studies published prior to the year 2000 and studies with evidence levels III-IV. Study quality was assessed using the Cochrane Collaboration's risk of bias tool. RESULTS: Seven level of evidence I-II studies were retained including 190 ACLR and 221 repairs (75 Bridge-Enhanced ACL Repair (BEAR), 49 Suture Augmentation (SA), and 97 Dynamic Intraligamentary Stabilization (DIS)). At final follow-up, re-rupture rates varied between 0-14% (BEAR) vs 0-6% (ACLR) and mean side-to-side differences measured using KT-1000 testing ranged from 1.6-1.9mm (BEAR) vs 1.7-3.14mm (ACLR). For DIS vs ACLR, mean anterior tibial translation values at final follow-up were 1.7mm (DIS) vs. 1.4mm (ACLR), and re-rupture rates ranged from 20.8%-29% (DIS) vs. 17%-27.2% (ACLR). For SA vs ACLR, the mean side to side difference ranged from 0.2-0.39mm (SA) vs 0.33-0.4mm (ALCR), while the re-rupture rates were 10% (SA) vs. 0% (ACLR). International Knee Documentation Committee (IKDC), Tegner, Lysholm and Knee Injury and Osteoarthritis Outcome (KOOS) scores across both cohorts exhibited statistically significant, and comparable improvement, from baseline to final follow-up ranging from 1 to 5 years. CONCLUSION: Augmented ACL repair results in similar patient reported outcomes measures in comparison to ACL reconstruction. However, augmented ACL repair may be associated with higher rates of failure given re-rupture rates of up to 14%, 29% and 10% for BEAR, DIS and SA, respectively. LEVEL OF EVIDENCE: II; Systematic review of level I-II studies.

Neuroanatomical and clinical factors predicting future cognitive impairment.

Identifying cognitively normal (CN) older adults who will convert to cognitive impairment (CI) due to Alzheimer's disease is crucial for early intervention. Clinical and neuroimaging measures were acquired from 301 CN adults who converted to CI within 15 years of baseline, and 294 who did not. Regional volumes and brain age measures were extracted from T1-weighted magnetic resonance images. Linear discriminant analysis compared non-converters' characteristics against those of short-, mid-, and long-term converters. Conversion was associated with clinical measures such as hearing impairment and self-reported memory decline. Converters' brain volumes were smaller than non-converters' across 48 frontal, temporal, and subcortical structures. Brain age measures of 12 structures were correlated with shorter times to conversion. Conversion prediction accuracy increased from 81.5% to 90.5% as time to conversion decreased. Proximity to CI conversion is foreshadowed by anatomic features of brain aging that enhance the accuracy of predicting conversion.

Influence of Lead Knee Extension on Ball Velocity and Elbow Varus Torque in Professional and High School Baseball Pitchers.

Background: When the lead leg of a pitcher contacts the ground, the knee braces and then rapidly extends, initiating energy transfer to begin pelvis and trunk rotation. Purpose: To investigate the relationship of lead knee extension during the pitching delivery with peak lead knee extension velocity, ball velocity, and elbow varus torque in high school and professional pitchers. Study Design: Descriptive laboratory study. Methods: Data from 50 professional (PRO) and 50 high school (HS) pitcher groups were retrospectively analyzed. Pitchers threw 8 to 12 fastballs under 3-dimensional motion analysis (480 Hz). The groups were divided according to high or low lead knee extension: PRO-high (n = 18), PRO-low (n = 16), HS-high (n = 16), and HS-low (n = 17). Lead knee flexion, lead knee extension velocity, ball velocity, and elbow varus torque were analyzed between groups. Regression analyses were performed to quantify associations between lead knee extension and ball velocity and elbow varus torque for all pitchers. Results: At foot contact, all pitchers landed with similar knee flexion. PRO-high and HS-high pitchers had significantly greater lead knee extension through remaining pitching time points compared with the PRO-low and HS-low pitchers. PRO-high pitchers had faster ball velocity than PRO-low pitchers (39.8 ± 1.1 vs 39.3 ± 1.3 m/s, respectively), and HS-high pitchers had faster ball velocity than HS-low pitchers (34.1 ± 2.6 vs 31.2 ± 1.8 m/s, respectively) (P < .05). PRO-high pitchers had decreased elbow varus torque compared with PRO-low pitchers (85.3 ± 10.7 vs 95.4 ± 13.3 N·m, respectively); conversely, HS-high pitchers had greater elbow varus torque than HS-low pitchers (64.2 ± 14.7 vs 56.3 ± 12.2 N·m, respectively). For every 1° increase in lead knee extension, ball velocity increased by 0.47 m/s (P < .001) and elbow varus torque increased by 0.27 N·m (P = .025). Conclusion: Proper lead knee extension allowed efficient energy transfer through the kinetic chain to produce optimal ball velocity and minimize elbow varus torque in professional pitchers. Conversely, while proper lead knee extension improved ball velocity among high school pitchers, this did not minimize elbow varus torque. Clinical Relevance: Professional pitchers can extend their lead knee with minimal impact at the elbow. In high school pitchers, cognizance of proper full-body pitching mechanics remains a priority over increased velocity.

Editorial Commentary: Arthroscopic Subacromial Balloon Spacer for Massive Rotator Cuff Tears Results in Fast Recovery and Lasting Pain Relief.

Repair of rotator cuff tear is challenging because poor biologic factors can negatively impact tendon healing and risk complications. Sometimes, instead of attempting complex procedures with a guarded prognosis to reconstruct or replace rotator cuff like tissue, less is more. Minimally invasive, arthroscopic subacromial balloon spacer (SBS) for massive rotator cuff tears, demonstrates excellent long-term outcomes. Radiographically, SBS outcomes may be concerning, but clinically, patients do well. If pain is the primary complaint and function is maintained, the balloon spacer is an excellent option with a fast recovery. However, if function is deficient, or if the patient prioritizes strength recovery as their primary desired outcome, then more invasive procedures are often indicated.

3D chromatin-based variant-to-gene maps across 57 human cell types reveal the cellular and genetic architecture of autoimmune disease susceptibility.

A portion of the genetic basis for many common autoimmune disorders has been uncovered by genome-wide association studies (GWAS), but GWAS do not reveal causal variants, effector genes, or the cell types impacted by disease-associated variation. We have generated 3D genomic datasets consisting of promoter-focused Capture-C, Hi-C, ATAC-seq, and RNA-seq and integrated these data with GWAS of 16 autoimmune traits to physically map disease-associated variants to the effector genes they likely regulate in 57 human cell types. These 3D maps of gene cis-regulatory architecture are highly powered to identify the cell types most likely impacted by disease-associated genetic variation compared to 1D genomic features, and tend to implicate different effector genes than eQTL approaches in the same cell types. Most of the variants implicated by these cis-regulatory architectures are highly trait-specific, but nearly half of the target genes connected to these variants are shared across multiple autoimmune disorders in multiple cell types, suggesting a high level of genetic diversity and complexity among autoimmune diseases that nonetheless converge at the level of target gene and cell type. Substantial effector gene sharing led to the common enrichment of similar biological networks across disease and cell types. However, trait-specific pathways representing potential areas for disease-specific intervention were identified. To test this, we pharmacologically validated squalene synthase, a cholesterol biosynthetic enzyme encoded by the FDFT1 gene implicated by our approach in MS and SLE, as a novel immunomodulatory drug target controlling inflammatory cytokine production by human T cells. These data represent a comprehensive resource for basic discovery of gene cis-regulatory mechanisms, and the analyses reported reveal mechanisms by which autoimmune-associated variants act to regulate gene expression, function, and pathology across multiple, distinct tissues and cell types.

Geniculate Artery Embolization for the Treatment of Mild to Moderate Knee Osteoarthritis Improves Pain and Function at Short-Term Follow-Up With Significant Procedural Heterogeneity Described Across the Literature: A Systematic Review.

PURPOSE: To evaluate procedural heterogeneity, patient-reported outcomes (PROs), and complications following geniculate artery embolization (GAE) for knee osteoarthritis (OA). METHODS: A literature search was performed using PubMed, Embase, and Scopus databases from inception to August 2023 according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Human clinical studies reporting PROs following GAE for treatment of knee OA were included, and a qualitative comparison across PROs, procedural descriptions, and complications was performed. Study quality was assessed using the Cochrane Collaboration's risk of bias tool and the Methodological Index for Non-Randomized Studies criteria. The primary outcome measures included changes in PROs at 12 months and variances in procedural methodology. RESULTS: A total of 17 studies, consisting of 533 patients and 620 knees, were identified. The reported mean improvement at 12 months for visual analog scale for pain and Western Ontario and McMaster Universities Arthritis Index scores ranged from 10 to 59 and 35.3 to 47, respectively. At 12 months, median improvements were observed in Knee injury and Osteoarthritis Outcome Score subscales such as Pain (range, 8.3-19.5), Quality of Life (15.49-25.0), Sport (7.5-26.3), and Symptoms (1.8-25.0). Decreasing minimal clinically important difference (MCID) achievement was observed between the 3-month and 6-month follow-up points. Patients with advanced OA and degenerative findings on magnetic resonance imaging exhibited lower rates of MCID achievement. Transient adverse events occurred in up to 80% of patients. Limited evidence from serial magnetic resonance imaging assessments suggests that GAE improves levels of synovitis. Significant heterogeneity exists among the GAE methodology as 4 different definitions of technical success, 4 distinct embolization targets, and use of 5 embolization agents were noted. CONCLUSIONS: GAE results in short-term improvements in pain and function with decreasing MCID achievement observed after 3 to 6 months. Patients with severe OA also demonstrate lower rates of MCID achievement. A high rate of transient complications is reported, including skin discoloration and access site hematomas. Significant protocol heterogeneity exists, which contributes to variable outcomes. LEVEL OF EVIDENCE: Level IV, systematic review of Level IV studies.

Greater Postoperative Biceps Tendon Migration After Arthroscopic Suprapectoral or Open Subpectoral Biceps Tenodesis Correlates With Lower Patient-Reported Outcome Scores.

PURPOSE: To assess the relation between tendon migration, as measured by radiostereometric analysis, and patient-reported outcome measures (PROMs) after biceps tenodesis (BT); to determine the likelihood of achieving clinically significant outcomes (CSOs) after BT; and to identify factors that impact CSO achievement. METHODS: Patients undergoing arthroscopic suprapectoral or open subpectoral BT at a single, high-volume academic medical center were prospectively enrolled. A tantalum bead sutured to the tenodesis construct was used as a radiopaque marker. Biceps tendon migration was measured on calibrated radiographs at 12 weeks postoperatively. PROMs (Constant-Murley, Single Assessment Numeric Evaluation [SANE], and Patient-Reported Outcomes Measurement Information System-Upper Extremity [PROMIS-UE] scores) were collected preoperatively and at minimum 2-year follow-up. RESULTS: Of 115 patients enrolled, 94 (82%) were included (median age, 52 years; median body mass index, 31.4). At a mean follow-up of 2.9 years, the median Constant-Murley, SANE, and PROMIS-UE scores were 33 (interquartile range [IQR], 26-35), 90 (IQR, 80-99), and 47 (IQR, 42-58), respectively. Median tantalum bead migration was 6.5 mm (IQR, 1.8-13.8 mm). There were significant correlations between migration and Constant-Murley score (r2 = 0.222; ß = -0.554 [95% confidence interval (CI), -1.027 to -0.081]; P = .022), SANE score (r2 = 0.238; ß = -0.198 [95% CI, -0.337 to -0.058]; P = .006), and PROMIS-UE score (r2 = 0.233; ß = -0.406 [95% CI, -0.707 to -0.104]; P = .009). On univariable analysis, higher body mass index was associated with achievement of substantial clinical benefit (unadjusted odds ratio [OR], 1.078 [95% CI, 1.007 to 1.161]; P = .038). Greater bead migration was negatively associated with achievement of the minimal clinically important difference (unadjusted OR, 0.969 [95% CI, 0.943 to 0.993]; P = .014) and patient acceptable symptomatic state (unadjusted OR, 0.965 [95% CI, 0.937 to 0.989]; P = .008) on all 3 instruments. CONCLUSIONS: A 1-cm increase in post-tenodesis biceps tendon migration was associated with a decrease in the Constant-Murley, SANE, and PROMIS-UE scores of 6, 2, and 4 points, respectively, at a mean of 2.9 years after surgery. Most patients achieved CSOs for these PROMs by latest follow-up, and greater biceps tendon construct migration was negatively associated with the likelihood of CSO achievement. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Inlay Scaffold Augmentation of Rotator Cuff Repairs Enhances Histologic Resemblance to Native Enthesis in Animal Studies: A Systematic Review.

PURPOSE: To investigate the outcomes of inlay positioned scaffolds for rotator cuff healing and regeneration of the native enthesis after augmentation of rotator cuff tendon repairs in preclinical studies. METHODS: A literature search was performed using the PubMed, Embase, and Cumulative Index to Nursing and Allied Health Literature databases according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Preclinical studies reporting on outcomes after inlay tendon augmentation in rotator cuff repair were included. Preclinical study quality was assessed using an adapted version of the Gold Standard Publication Checklist for animal studies. The level of evidence was defined based on the inclusion of clinical analyses (grade A), biomechanical analyses (grade B), biochemical analyses (grade C), semiquantitative analyses (grade D), and qualitative histologic analyses (grade E). RESULTS: Thirteen preclinical studies met the inclusion criteria. Quality assessment scores ranged from 4 to 8 points, and level-of-evidence grades ranged from B to E. Sheep/ewes were the main animal rotator cuff tear model used (n = 7). Demineralized bone matrix or demineralized cortical bone was the most commonly investigated scaffold (n = 6). Most of the preclinical evidence (n = 10) showed qualitative or quantitative differences regarding histologic, biomechanical, and biochemical outcomes in favor of interpositional scaffold augmentation of cuff repairs in comparison to controls. CONCLUSIONS: Inlay scaffold positioning in preclinical studies has been shown to enhance the healing biology of the enthesis while providing histologic similarities to its native 4-zone configuration. CLINICAL RELEVANCE: Although onlay positioned grafts and scaffolds have shown mixed results in preclinical and early clinical studies, inlay scaffolds may provide enhanced healing and structural support in comparison owing to the ability to integrate with the bone-tendon interface.

Deciphering the molecular landscape of human peripheral nerves: implications for diabetic peripheral neuropathy.

Diabetic peripheral neuropathy (DPN) is a prevalent complication of diabetes mellitus that is caused by metabolic toxicity to peripheral axons. We aimed to gain deep mechanistic insight into the disease process using bulk and spatial RNA sequencing on tibial and sural nerves recovered from lower leg amputations in a mostly diabetic population. First, our approach comparing mixed sensory and motor tibial and purely sensory sural nerves shows key pathway differences in affected nerves, with distinct immunological features observed in sural nerves. Second, spatial transcriptomics analysis of sural nerves reveals substantial shifts in endothelial and immune cell types associated with severe axonal loss. We also find clear evidence of neuronal gene transcript changes, like PRPH, in nerves with axonal loss suggesting perturbed RNA transport into distal sensory axons. This motivated further investigation into neuronal mRNA localization in peripheral nerve axons generating clear evidence of robust localization of mRNAs such as SCN9A and TRPV1 in human sensory axons. Our work gives new insight into the altered cellular and transcriptomic profiles in human nerves in DPN and highlights the importance of sensory axon mRNA transport as an unappreciated potential contributor to peripheral nerve degeneration.

Balloon Spacer Implant Is an "Intermediate Value" Innovation Relative to Partial Repair for Full-Thickness Massive Rotator Cuff Repairs: A Cost-Utility Analysis.

PURPOSE: To evaluate the cost-utility of a balloon spacer implant relative to partial repair (PR) for the surgical treatment of full-thickness massive rotator cuff tears (MRCTs). METHODS: A decision-analytic model comparing balloon spacer with PR was developed using data from a prospective, randomized, single-blinded, multicenter-controlled trial of 184 randomized patients. Our model was constructed on the basis of the various event pathways a patient could have after the procedure. The probability that each patient progressed to a given outcome and the quality-adjusted life years (QALY) associated with each outcome were derived from the clinical trial data. Incremental cost utility ratio (ICUR) and incremental net monetary benefit were calculated on the basis of a probabilistic sensitivity analysis using Monte Carlo simulations of 1,000 hypothetical patients progressing through the decision-analytic model. One-way sensitivity and threshold analyses were performed by varying cost, event probability, and QALY estimates. RESULTS: The balloon spacer had an ICUR of $106,851 (95% confidence interval $96,317-$119,143) relative to PR for surgical treatment of MRCT. Across all patients, the balloon spacer was associated with greater 2-year QALY gain compared with PR (0.20 ± 0.02 for balloon spacer vs 0.18 ± 0.02 for PR), but with substantially greater total 2-year cost ($9,701 ± $939 for balloon spacer vs $6,315 ± $627 for PR). PR was associated with a positive incremental net monetary benefit of $1,802 (95% confidence interval $1,653-$1,951) over balloon spacer at the $50,000/QALY willingness-to-pay threshold. CONCLUSIONS: Compared with PR, the balloon spacer is an "intermediate-value" innovation for treatment of MRCT over a 2-year postoperative period with an ICUR value that falls within the $50,000 to $150,000 willingness-to-pay threshold. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Comparing MRI and arthroscopic appearances of common knee pathologies: A pictorial review.

Knee pathology, including anterior cruciate ligament (ACL) tears, meniscal tears, articular cartilage lesions, and intra-articular masses or cysts are common clinical entities treated by orthopedic surgeons with arthroscopic surgery. Preoperatively, magnetic resonance imaging (MRI) is now standard in confirming knee pathology, particularly detecting pathology less evident with history and physical examination alone. The radiologist's MRI interpretation becomes essential in evaluating intra-articular knee structures. Typically, the radiologist that interprets the MRI does not have the opportunity to view the same pathology arthroscopically. Thus, the purpose of this article is to illustratively reconcile what the orthopedic surgeon sees arthroscopically with what the radiologist sees on magnetic resonance imaging when viewing the same pathology. Correlating virtual and actual images can help better understand pathology, resulting in more accurate MRI interpretations. In this article, we present and review a series of MR and correlating arthroscopic images of ACL tears, meniscal tears, chondral lesions, and intra-articular masses and cysts. Short teaching points are included to highlight the importance of radiological signs and pathological MRI appearance with significant clinical and arthroscopic findings.

Blood Flow Restriction Enhances Recovery After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

PURPOSE: To conduct a systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating neuromuscular and clinical outcomes of blood flow restriction (BFR) training after anterior cruciate ligament reconstruction (ACLR) compared with non-BFR rehabilitation protocols. METHODS: A systematic review was performed in accordance with the 2020 Preferred Reporting Items for Systematic reviews and Meta Analyses guidelines by querying PubMed, MEDLINE, Scopus, the Cochrane Database for Systematic Review, and the Cochrane Central Register for Controlled Trials databases from inception through December 2023 to identify Level I and II RCTs evaluating outcomes of BFR training after ACLR compared with non-BFR rehabilitation. A meta-analysis was performed using random-effects models with standardized mean difference (SMD) for pain, muscle strength, and muscle volume, whereas mean difference was calculated for patient-reported outcome measures. RESULTS: Eight RCTs, consisting of 245 patients, met inclusion criteria, with 115 patients undergoing non-BFR rehabilitation compared with 130 patients undergoing BFR after ACLR. Mean patient age was 27.2 ± 6.7 years, with most patients being male (63.3%, n = 138/218). The length of the BFR rehabilitation protocol was most commonly between 8 and 12 weeks (range, 14 days to 16 weeks). Most studies set the limb/arterial occlusion pressure in the BFR group at 80%. When compared with non-BFR rehabilitation, BFR resulted in significant improvement in isokinetic muscle strength (SMD: 0.77, P = .02, I2: 58%), International Knee Documentation Committee score (mean difference: 10.97, P ≤ .00001, I2: 77%), and pain (SMD: 1.52, P = .04, I2: 87%), but not quadriceps muscle volume (SMD: 0.28, P = .43, I2: 76%). CONCLUSIONS: The use of BFR after ACLR led to improvements in pain, International Knee Documentation Committee score, and isokinetic muscle strength, with variable outcomes on the basis of quadriceps strength, volume, and thickness when compared with non-BFR rehabilitation. LEVEL OF EVIDENCE: Level II, systematic review and meta-analysis of Level I and II studies.

Lower Range of Recurrent Instability Rates Following Bankart Repair and Remplissage Compared to Isolated Bankart Repair in Patients With "Nonengaging/On-Track" Hill-Sachs Lesions and <20% Glenoid Bone Loss.

PURPOSE: To compare recurrent instability and return-to-sport rates along with external rotation differences between on-track (nonengaging) Hill-Sachs lesion patients undergoing either an isolated Bankart repair (IBR) or a Bankart repair augmented with a remplissage procedure (B+R). METHODS: A search was conducted using 3 databases (PubMed, EMBASE, CINAHL) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Only clinical comparative (level of evidence I-III) studies were considered for inclusion. Quality assessment was performed using the Methodological Index for Non-Randomized Studies criteria. RESULTS: Six level of evidence III studies, totaling 537 patients (202 B+R and 335 IBR) were included for analysis. All patients had <20% glenoid bone loss and a nonengaging, on-track Hill-Sachs lesion. At a median final follow-up of 34.7 months, recurrent dislocation rates ranged from 0% to 7.7% and 3.5% to 30% in the B+R and IBR groups, respectively. Moreover, subjective instability and revision surgery rates presented lower ranges in the B+R upon comparison with the IBR cohort (0%-32% vs 5%-71.4% and 0%-5% vs 0%-35%, respectively). Furthermore, return to preinjury level of sports ranged from 64% to 100% in the remplissage-augmented group and 50% to 90% in the IBR cohort. Postoperative external rotation at side varied from 50° to 63° in the B+R and 55° to 63° in the IBR arm. Additional subgroup analysis revealed recurrent dislocation rates in athletes and patients with near-track Hill-Sachs lesions undergoing remplissage augmentation to be 0% to 5% and 2% to 47% while ranging from 8.8% to 30% and 9% to 66% for IBR patients, respectively. CONCLUSIONS: Upon qualitative analysis, ranges of recurrent instability measures, including recurrent dislocation rates, are higher in patients undergoing IBR in comparison to B+R. Activity level influences outcomes as athletes were found to have a higher range of recurrent dislocation rates in the IBR group. The addition of remplissage showed a higher range of return-to-sport rates with comparable postoperative external rotation between groups. LEVEL OF EVIDENCE: Level III, systematic review of Level III studies.

A biomechanical study to optimize superior capsular reconstruction operative technique.

Background: The goals of this study were to optimize superior capsular reconstruction by assessing the relative fixation strength of 4 suture anchors; evaluating 3 glenoid neck locations for fixation strength and bone mineral density (BMD); determining if there is a correlation between BMD and fixation strength; and determining which portal sites have optimal access to the posterosuperior and anterosuperior glenoid neck for anchor placement. Methods: Twenty cadaveric specimens were randomized into 4 groups: all-suture anchor (FiberTak), conventional 3.0-mm knotless suture anchor (SutureTak), 3.9-mm knotless PEEK (polyetheretherketone) Corkscrew anchor, and 4.5-mm Bio-Corkscrew anchor. Each specimen was prepared with 3 anchors into the glenoid: an anterosuperior anchor, superior anchor, and posterosuperior anchor. All anchors were inserted into the superior glenoid neck 5 mm from the glenoid rim. A materials testing system performed cyclic testing (250 cycles) followed by load-to-failure testing at 12.5 mm/s. Cyclic elongation, first cycle excursion, maximum load, and stiffness were recorded. Using custom software, BMD was calculated at each anchor location. This software was also used to assess access to the posterosuperior and anterosuperior glenoid neck from standard arthroscopic portal positions. Results: There was no significant difference in cyclic elongation (P = .546), first cycle excursion (P = .476), maximum load (P = .817), or stiffness (P = .309) among glenoid anchor positions. Cyclic elongation was significantly longer in the PEEK Corkscrew group relative to the other implants (P ≤ .002). First cycle excursion was significantly greater in the FiberTak group relative to all other implants (P ≤ .008). For load-to-failure testing, the Bio-Corkscrew group achieved the highest maximum load (P ≤ .001). No other differences in cyclic or failure testing were observed between the groups. No differences in stiffness testing were observed (P = .133). The superior glenoid rim had the greatest BMD (P = .003), but there was no correlation between BMD and cyclic/load outcomes. The posterior portal (80% of specimens) and the anterior portal (60% of specimens) demonstrated the best access to the posterosuperior and anterosuperior glenoid neck, respectively. Conclusion: The 4.5-mm Bio-Corkscrew anchor provided the most robust fixation to the glenoid during superior capsular reconstruction as it demonstrated the strongest maximum load, had minimal elongation, had minimal first cycle excursion, and did not fail during cyclic testing. The superior glenoid neck had the highest BMD; however, there was no correlation between BMD or glenoid anchor location and biomechanical outcomes. The posterior portal and anterior portal provided optimal access to the posterosuperior glenoid neck and anterosuperior glenoid neck, respectively.

Increases in regional brain volume across two native South American male populations.

Industrialized environments, despite benefits such as higher levels of formal education and lower rates of infections, can also have pernicious impacts upon brain atrophy. Partly for this reason, comparing age-related brain volume trajectories between industrialized and non-industrialized populations can help to suggest lifestyle correlates of brain health. The Tsimane, indigenous to the Bolivian Amazon, derive their subsistence from foraging and horticulture and are physically active. The Moseten, a mixed-ethnicity farming population, are physically active but less than the Tsimane. Within both populations (N = 1024; age range = 46-83), we calculated regional brain volumes from computed tomography and compared their cross-sectional trends with age to those of UK Biobank (UKBB) participants (N = 19,973; same age range). Surprisingly among Tsimane and Moseten (T/M) males, some parietal and occipital structures mediating visuospatial abilities exhibit small but significant increases in regional volume with age. UKBB males exhibit a steeper negative trend of regional volume with age in frontal and temporal structures compared to T/M males. However, T/M females exhibit significantly steeper rates of brain volume decrease with age compared to UKBB females, particularly for some cerebro-cortical structures (e.g., left subparietal cortex). Across the three populations, observed trends exhibit no interhemispheric asymmetry. In conclusion, the age-related rate of regional brain volume change may differ by lifestyle and sex. The lack of brain volume reduction with age is not known to exist in other human population, highlighting the putative role of lifestyle in constraining regional brain atrophy and promoting elements of non-industrialized lifestyle like higher physical activity.