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Background: Significant controversy surrounds ideal tunnel position for medial patellofemoral ligament (MPFL) reconstruction (MPFLR) in the pediatric setting. The start point for femoral tunnel positioning (the Schöttle point) relative to the distal medial femoral physis is not well defined. Previous studies provide conflicting data regarding position of the MPFL origin and the Schöttle point relative to the distal femoral physis. Hypothesis: The Schöttle point would be consistently distal to the distal medial femoral physis. Study Design: Descriptive laboratory study. Methods: The institutional picture archiving and communication system was queried for computed tomography (CT) imaging studies of pediatric knees. Data were imported to an open-source image computing platform. True lateral digitally reconstructed radiographs and 3-dimensional (3D) renderings were generated, and the Schöttle point was registered in 3D space. Then, 3D distance measurements were obtained from the Schöttle point to the distal medial femoral physis. Results: A total of 49 pediatric knee CT scans were included. Mean age was 13.0 ± 2.3 years. Mean minimum distance from the medial physis to the Schöttle point was 9.9 ± 3.0 mm (range, 3.4-16.1 mm). In 49 of 49 cases (100%), the Schöttle point was distal to the physis. Using a 6-mm reaming diameter would result in 3 of 49 (6%) femurs having violation of the distal medial femoral physis. Moving the start point 3 mm distally would result in 0 of 49 (0%) sustaining physeal injury. Conclusion/Clinical Relevance: The Schöttle point is consistently distal to the distal medial femoral physis. The mean minimum distance from the Schöttle point to the physis on the medial cortex is 9.9 mm. The Schöttle point provides a safe and reliable radiographic landmark for pediatric MPFLR, although reaming diameter should be considered.

PURPOSE OF REVIEW: To characterize current concepts in capsular repair and hip instability, and examine findings from biomechanical and clinical studies on hip capsular management strategies as they pertain to hip stability, patient outcomes, and hip arthroscopy failure. Further, we discuss the clinical evaluation and treatment of capsular deficiency. RECENT FINDINGS: There remains debate regarding the optimal capsular management strategies in hip arthroscopy, particularly concerning the necessity of routine capsular repair. A variety of capsulotomy techniques exist and may be used to access the hip joint. Additionally, a wide variety of techniques are employed to repair the hip capsule. Biomechanical evidence supports capsular closure restores hip joint stability to that of the intact, native state. Several clinical studies in both primary and revision hip arthroscopy settings have demonstrated improved pain and functional outcomes in patients who underwent capsular repair or capsular reconstruction. Studies have shown capsular repair may be especially important in patients with ligamentous laxity and hip dysplasia, and in competitive athletes. SUMMARY: Post-surgical hip instability secondary to capsular insufficiency is increasingly recognized as a cause of hip arthroscopy failure. Capsular closure restores native biomechanical stability to the hip joint, and several clinical studies report improved pain and functional outcomes following capsular repair or capsular reconstruction in both the primary and revision hip arthroscopy settings. There remains much to learn regarding capsular hip instability as it relates to optimal capsular management surgical technique, intra-operative capsular management decision-making, clinical diagnosis, and related advanced imaging findings.

Sloths exhibit almost obligatory suspensory locomotion and posture. These behaviors require both strength and fatigue resistance, although we previously found muscle fiber type characteristics in the forelimbs of sloths that belied these initial expectations. Based on locomotor roles of the forelimbs versus hindlimbs in propulsion and braking, respectively, sloth hindlimb musculature should be adapted for force production and energy savings by a near homogeneous expression of slow myosin heavy chain (MHC) fibers. This hypothesis was tested by determining MHC fiber type (%) distribution and energy metabolism in the hindlimbs of three-toed (B. variegatus, N = 5) and two-toed (C. hoffmanni, N = 3) sloths. A primary expression of the slow MHC-1 isoform was found in the hindlimbs of both species. Slow MHC fiber type (%) was significantly greater in the flexors of B. variegatus, whereas expression of fast MHC-2A fibers was significantly greater in the extensors of C. hoffmannni. MHC-1 fibers were largest in cross-sectional area (CSA) and comprised the greatest %CSA in each muscle sampled from both species. Enzyme assays showed elevated activity for anaerobic enzymes (CK and LDH) compared with low-to-moderate activity for aerobic enzymes (3-HAD and CS), and only CK activity was related to body size. These findings emphasize a joint stabilization role by the hindlimbs during suspension, especially in smaller three-toed sloths, and suggest that larger two-toed sloths could have muscles further modified for greater power output and/or prolonged arboreal maneuvering. Moreover, modifications to muscle metabolism rather than MHC expression may be more reflective of functional adaptation in sloth limbs.

The Centers for Medicare and Medicaid Services (CMS) recently eliminated the requirement for preoperative history and physicals (HPs) prior to ambulatory surgery. We sought to assess variations in separately billed preoperative HP utilization prior to low-risk ambulatory surgery, describe any relationship with preoperative testing, and identify independent predictors of these consultations prior to this policy change to help characterize the potential unnecessary utilization of these consultations and potential unnecessary preoperative testing prior to low-risk surgery.A retrospective cohort study was performed using claims data from a hospital value collaborative in Michigan from January 2015 to June 2019 and included patients undergoing one of three ambulatory procedures: breast lumpectomy, laparoscopic cholecystectomy, and laparoscopic inguinal hernia repair. Rates of preoperative HP visits within 30 d of surgical procedure were determined. HP and preoperative testing associations were explored, and patient-level, practice-level, and hospital-level determinants of utilization were assessed with regression models. Risk and reliability-adjusted caterpillar plots were generated to demonstrate hospital-level variations in utilization.50,775 patients were included with 50.5% having a preoperative HP visit, with these visits being more common for patients with increased comorbidities (1.9 ± 2.2 vs 1.4 ± 1.9; P 0.0001). Preoperative testing was associated with HP visits (57.2% vs 41.4%; P 0.0001). After adjusting for patient case-mix and interhospital and intrahospital variations in HP visits, utilization remained with significant associations in patients with increased comorbidities.Preoperative HP visits were common before three low-risk ambulatory surgical procedures across Michigan and were associated with higher rates of low-value preoperative testing, suggesting that preoperative HP visits may create clinical momentum leading to unnecessary testing. These findings will inform strategies to tailor preoperative care before low-risk surgical procedures and may lead to reduced utilization of low-value preoperative testing.

To determine the incidence of screw impingement on dynamic exam during hip arthroscopy in patients undergoing treatment for femoroacetabular impingement after previous slipped capital femoral epiphysis fixation and to evaluate screw characteristics with hardware impingement.A retrospective review from 2008 to 2020 was performed of slipped capital femoral epiphysis (SCFE) patients that underwent arthroscopy for symptoms of hip impingement. Patients underwent a dynamic exam under direct arthroscopic visualization to assess for sources of impingement, including bony anatomy and fixation hardware. Slip angle was calculated on lateral radiographs prior to arthroscopy, and screw length was noted in the initial operative reports at treatment of SCFE and reported in millimeters. Normality of data was assessed using Shapiro-Wilk tests, with statistical analysis performed using independent sampleThirty-nine hips were included, with 13 (33.3%) having screw impingement on dynamic exam. Slip angle was found to be increased in the screw impingement group (42.4° vs 35.5°;Shorter screws (55 mm or less) are at greater risk of causing hardware hip impingement after in situ SCFE fixation. When considering hip arthroscopy for the treatment of femoroacetabular impingement in patients with a previous SCFE, hardware impingement and subsequent hardware removal should be considered in hips with shorter screws and in hips that show objective hardware impingement on dynamic exam.Level IV, therapeutic case series.

Juvenile osteochondritis dissecans (OCD) of the knee is a defect of subchondral bone seen primarily in active children and adolescents. Studies have evaluated the incidence of surgery in knee OCD, but the incidence of subsequent surgery in patients with stable, healing lesions cleared to return to activities is unknown. This study sought to determine the incidence of surgery in participants with knee OCD lesions cleared to return to activities and evaluate predictors of subsequent surgery.A single center, retrospective review was performed of participants aged 7 to 18 with knee OCD. Inclusion criteria were stable lesion, skeletal immaturity, no history of previous knee surgery, release to activity without surgery, and at least 12 months of follow-up. Documentation of subsequent surgery was queried in the electronic health record. Participants with no recorded surgery were contacted through phone. Analysis included bivariate and logistic regression.Twenty-five individuals were included in this study, with 7 undergoing surgery after returning to activity. Medial femoral condyle lesions were less likely to undergo surgery (B=-2.6, P=0.038). Average lesion size for the Surgery and No Surgery groups was 1.76±0.65 and 1.32±0.81 cm2, respectively, though not significantly different (P=0.21). The Surgery group returned to activity sooner (3.7 mo, range 1.1 to 6.4) than the No Surgery group (8.1 mo, range 1.8 to 35.4), though not significantly different (P=0.18). Mean follow-up time for the study was 42.7 (range 12.6 to 77.6) months. No participants contacted by phone progressed to surgery or reported symptoms that limited their activities.While the majority of participants with stable, healing, and asymptomatic knee OCD lesions have favorable outcomes with nonoperative management, some lesions may progress to surgery. Lesions on the medial femoral condyle may be predictive of lower likelihood of progression to surgery. Our study provides insight on the outcomes of nonoperative management of OCD lesions.Level IV-prognostic study.

To investigate the relation of hip capsular thickness as measured on preoperative magnetic resonance imaging (MRI) and intraoperative hip joint axial distraction distance on an examination under anesthesia.A retrospective review of primary arthroscopic hip procedures performed between November 2018 and June 2021 was conducted. The inclusion criteria included a diagnosis of femoroacetabular impingement syndrome and preoperative radiographic imaging and MRI. Fluoroscopic images were obtained at 0 lb and 100 lb of axial traction force. Total distraction distance was calculated by comparing the initial joint space with the total joint space at 100 lb. Hip capsular thickness was measured on MRI. Analysis was conducted using multiple linear regression, independent-samples t tests, and Mann-Whitney U tests.Eighty patients were included. Bivariable regression showed an association between an increased distraction distance and female sex (β = 4.303, R = 0.561, P.001), as well as decreased anterior axial (β = -1.291, R = 0.365, P.001) and superior coronal (β = -1.433, R = 0.501, P.001) capsular thickness. Multivariable regression (R = 0.645) showed an association between an increased distraction distance and female sex (β = 3.175, P.001), as well as decreased superior coronal capsular thickness (β = -0.764, P = .022). Independent-samples t tests showed that female patients had significantly decreased superior coronal capsular thickness (2.92 ± 1.14 mm vs 3.99 ± 1.15 mm, P.001).Female sex and decreased hip capsular thickness in the superior aspect of the coronal plane on magnetic resonance scans were found to be predictors of increased hip joint axial distraction distance on examination under anesthesia prior to hip arthroscopy, with anterior axial capsular thickness being a moderate predictor. Poor predictors of distraction distance were posterior axial and inferior coronal capsular thickness, age, body mass index, and lateral center-edge angle. Female patients were also found to have thinner hip capsules in the superior region, which may explain the association between female patients and increased distraction. These findings further characterize the relation between capsular thickness and hip laxity.Level IV, case series.

Background: Rehabilitation is an important component of care in postsurgical knee patients, especially as it pertains to return to preinjury activity level. Despite the established significance of rehabilitation in improving outcomes after certain surgical procedures, there is a lack of investigation into compliance rates and factors that affect compliance in pediatric patients. Purpose/Hypothesis: The purpose of this study was to evaluate sociodemographic factors associated with noncompliance in pediatric patients after knee surgery to characterize health disparities in this population. Our hypothesis was that certain sociodemographic factors would be associated with decreased compliance. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A retrospective review of medical records was used to gather data on compliance rate, demographics, and socioeconomic factors for pediatric patients undergoing rehabilitation after knee surgery. Compliance rate was determined by counting the total scheduled appointments, cancellations, and no-shows (defined as visits for which patients did not show up and did not provide notification of cancellation). Various types of knee injuries were included in this study. Data were evaluated using bivariate analyses in addition to hierarchical linear and binary logistic regression to assess for associations between sociodemographic factors and compliance rate. Results: Our total sample size was 186 patients. When compared with patients from non–single-parent households, patients from single-parent households were found to have a lower rate of physical therapy compliance (72.2% vs 80.1%; P < .001), were less likely to reach the 85% compliance threshold (9.1% vs 42.4%; P < .001), and had an increased amount of cancellations and no-shows (16.7 vs 11.7 visits; P = .02). Although a small sample size, Hispanic/Latino patients were shown to have a lower achievement of the 85% compliance threshold compared with non-Hispanic/Latino patients (0% vs 38.2%; P = .04). Increased distance from the rehabilitation clinic was associated with lower achievement of the 85% compliance threshold ( P = .033). Conclusion: Overall, there were several significant demographic and socioeconomic variables associated with rehabilitation compliance, specifically single-parent status, distance to rehabilitation clinic, and ethnicity. These results suggest potential predictors of decreased compliance that warrant prospective investigation.

With rising healthcare costs and campaigns aimed at avoiding low-value care, reducing cancer overtreatment has emerged as an important measure of cancer care quality. The extent to which avoidance of low-value care has been incorporated in cancer-specific quality measures is unknown. We aimed to identify and characterize cancer quality measures that promote the avoidance of low-value care, and identify gaps that may guide future measure development.We systematically identified cancer-specific quality measures from leading quality measure organizations [e.g., National Quality Forum (NQF), National Quality Measures Clearinghouse (NQMC)]. We reviewed measures promoting the avoidance of low-value cancer care and subclassified them into disease site- or non-disease site-specific categories and the phase of care they targeted.We reviewed 313 quality measures from six organizations. Of these, 18% (n = 55) focused on avoidance of low-value care. Quality measures focused on end-of-life care were most likely to focus on low-value care [n = 13 (50%)], followed by breast [n = 12 (18%)], lung [n = 9 (31%)], colon [n = 8 (20%)], prostate [n = 5 (38%)], general cancer care [n = 4 (3%)], symptoms and toxicities [n = 2 (40%)], and palliative cancer care [n = 2 (11%)] measures. The phases of care quality measures targeted included low-value screening [n = 5 (9%)], diagnostic testing and staging [n = 7 (13%)], treatment [n = 19 (34%)], surveillance [n = 6 (11%)], and clinical outcomes [n = 18 (33%)]. All categories had a treatment-specific quality measure, but no category had a representative measure for every phase of care.A minority of cancer quality measures are aimed at avoiding low-value care, and multiple evidence-based recommendations targeting low-value care have not been incorporated.

Hip arthroscopy has proven to be an effective surgical approach for the treatment of femoroacetabular impingement (FAI) syndrome. Studies have shown that patients typically have improved functional outcomes and high rates of return to activity following cam lesion resection and reshaping of the femoral head-neck junction. However, despite these favorable outcomes, there is still a steep and well-recognized learning curve in FAI hip arthroscopy. Although it is common dogma to consider an ideal reshaping of the femoral head-neck junction as being perfectly spherical, the ability to achieve this intraoperatively can be quite challenging. A new tool is the "femoroacetabular impingement resection (FAIR) arc," measured on a 45° Dunn lateral radiograph where a best-fit circle incorporates the region immediately inferior to the anteroinferior iliac spine, the subspine region, and lateral femoral neck base. The maximal radial distance height is then measured from the circumference of this circle to the apex of the cam lesion. This radiographic aid may assist with intraoperative estimate of appropriate cam lesion resection depth. While I tend to utilize preoperative radiographs and intra-operative neck sclerosis to determine cam resection depth, I continue to seek out other ways to effectively perform a femoral osteoplasty. While my initial attempt to utilize the FAIR index in my practice did not seem effective, I will continue to test this measurement in my patients.

Purpose: To quantify the magnetic resonance arthrography (MRA) capsular morphologic findings associated with postarthroscopy hip instability. Methods: Among patients with clinically significant iatrogenic hip instability at a single center, patients with preindex and postindex surgery MRAs were identified. These MRAs were compared regarding effective intracapsular volume calculated by semi-automated 3-dimensional pixel intensity region segmentation, 2-dimensional anterior proximal intracapsular area in the femoral neck axial plane reconstruction, maximal anterior fluid pocket depth, capsule retraction distance, and capsular instability grade. Morphological measurements were conducted using Horos image processing software. Paired t-test, paired Wilcoxon signed rank test, and the McNemar test were used for identifying statistical significance. Results: In 42 patients, mean effective intracapsular volume was significantly greater in the postindex surgery MRAs (19.44 cm3 vs 17.26 cm3; P = .006). Proximal anterosuperior (12-3 o'clock) intracapsular area was also significantly greater after index surgery (2.84 cm2 vs 1.43 cm2; P < .001. Proximal anteroinferior (3-6 o'clock) intracapsular area (1.34 cm2 vs 0.97 cm2; P = .002), capsule deficiency grade (P < .001), anterior capsule retraction distance (4.83 mm vs 0.34 mm; P < .001), and maximum anterior fluid depth (8.33 mm vs 4.90 mm; P

Case A 13-year-old boy sustained an acute, grade III medial collateral ligament (MCL) distal periosteal avulsion injury while playing noncontact football. Treatment consisted of diagnostic knee arthroscopy with open physeal-sparing MCL repair. At approximately 1-year follow-up, new development of genu valgum in the operative extremity was noted. After 8 months of nonoperative treatment with deformity progression, the patient underwent correction with proximal medial tibial hemiepiphysiodesis. Conclusion Although Cozen's phenomenon commonly occurs after a proximal metaphyseal tibial fracture in children aged 2 to 7 years, it can occur as a rare complication of MCL injury/repair and remains a possible outcome in skeletally immature patients.

INTRODUCTION: Guidelines allow for the omission of sentinel lymph node biopsy (SLNB) and post-lumpectomy radiotherapy in women ≥70 years old with hormone receptor positive (HR+) breast cancer. Despite this, national data suggest these procedures have not been widely de-implemented. Our objectives were to evaluate trends in SLNB and post-lumpectomy radiotherapy utilization in patients who are eligible for omission and evaluate patient preferences as a target for de-implementation of low-value care. METHODS: We performed a sequential explanatory mixed-methods study by first analyzing an institutional database of patients ≥70 years old with HR+ breast cancer who received surgical treatment from 2014-2018. Based on the quantitative data, we conducted semi-structured interviews with women identified as high or low utilizers of breast cancer treatments to elicit patient perspectives on de-implementation. RESULTS: SLNB and post-lumpectomy radiotherapy were performed in 68% and 43% of patients who met criteria for omission, respectively. There was a significant decrease in SLNB rates from 2014-2018. Forty-nine percent of patients were classified as high utilizers and 26% were classified as low utilizers. Qualitative analysis found that the most important factors influencing decision-making regarding SLNB and post-lumpectomy radiotherapy omission for both high and low utilizers were trust in their provider and desire for peace of mind. CONCLUSIONS: Despite efforts to de-implement low-value care, older women with HR+ breast cancer remain at risk of overtreatment. Patient perspectives suggest that multi-level de-implementation strategies will need to target provider practice patterns and patient-provider communication to promote high quality decision-making and reduction in breast cancer overtreatment.

Background Patients undergoing deep vein thrombosis (VT) have over 30% recurrence, directly increasing their risk of post-thrombotic syndrome. Current murine models of inferior vena cava (IVC) VT model host one thrombosis event. Objective We aimed to develop a murine model to study IVC recurrent VT in mice. Materials and Methods An initial VT was induced using the electrolytic IVC model (EIM) with constant blood flow. This approach takes advantage of the restored vein lumen 21 days after a single VT event in the EIM demonstrated by ultrasound. We then induced a second VT 21 days later, using either EIM or an IVC ligation model for comparison. The control groups were a sham surgery and, 21 days later, either EIM or IVC ligation. IVC wall and thrombus were harvested 2 days after the second insult and analysed for IVC and thrombus size, gene expression of fibrotic markers, histology for collagen and Western blot for citrullinated histone 3 (Cit-H3) and fibrin. Results Ultrasound confirmed the first VT and its progressive resolution with an anatomical channel allowing room for the second thrombus by day 21. As compared with a primary VT, recurrent VT has heavier walls with significant up-regulation of transforming growth factor-β (TGF-β), elastin, interleukin (IL)-6, matrix metallopeptidase 9 (MMP9), MMP2 and a thrombus with high citrullinated histone-3 and fibrin content. Conclusion Experimental recurrent thrombi are structurally and compositionally different from the primary VT, with a greater pro-fibrotic remodelling vein wall profile. This work provides a VT recurrence IVC model that will help to improve the current understanding of the biological mechanisms and directed treatment of recurrent VT.

Sloths exhibit almost obligatory suspensory locomotion and posture. These behaviors require both strength and fatigue resistance, although we previously found muscle fiber type characteristics in the forelimbs of sloths that belied these initial expectations. Based on locomotor roles of the forelimbs versus hindlimbs in propulsion and braking, respectively, sloth hindlimb musculature should be adapted for force production and energy savings by a near homogeneous expression of slow myosin heavy chain (MHC) fibers. This hypothesis was tested by determining MHC fiber type (%) distribution and energy metabolism in the hindlimbs of three-toed (B. variegatus, N = 5) and two-toed (C. hoffmanni, N = 3) sloths. A primary expression of the slow MHC-1 isoform was found in the hindlimbs of both species. Slow MHC fiber type (%) was significantly greater in the flexors of B. variegatus, whereas expression of fast MHC-2A fibers was significantly greater in the extensors of C. hoffmannni. MHC-1 fibers were largest in cross-sectional area (CSA) and comprised the greatest %CSA in each muscle sampled from both species. Enzyme assays showed elevated activity for anaerobic enzymes (CK and LDH) compared with low-to-moderate activity for aerobic enzymes (3-HAD and CS), and only CK activity was related to body size. These findings emphasize a joint stabilization role by the hindlimbs during suspension, especially in smaller three-toed sloths, and suggest that larger two-toed sloths could have muscles further modified for greater power output and/or prolonged arboreal maneuvering. Moreover, modifications to muscle metabolism rather than MHC expression may be more reflective of functional adaptation in sloth limbs.

Background: Rehabilitation is paramount to recovery following surgery for ligamentous and meniscal knee injuries, but there exists little research regarding adherence with rehabilitation in pediatric populations, especially how this relates to health disparities in this population. Hypothesis/Purpose: Our study aimed to evaluate the effect of patient socioeconomic/demographic factors on adherence with physical therapy appointments following surgical repair or reconstruction of knee injuries. This information would be used to raise awareness of health disparities and potentially develop a set of predictors for a higher risk of non-adherence with prescribed rehabilitation. Methods: This study was a retrospective chart review of patients under the age of 18 who underwent physical therapy at the authors’ institution following initial surgical repair or reconstruction of a knee injury (ACL, MCL, LCL, PCL, meniscus, patellar tendon, and tibial eminence injuries included). Surgeries from 1 January 2015 to 31 December 2016 were considered, with physical therapy being considered for dates extending to 1 January 2018. Rate of adherence with physical therapy, reasons for lack of attendance, and socioeconomic/demographic variables were gathered. Data was evaluated utilizing bivariate and separate hierarchical linear regression analyses. Results: Our study population was comprised of 108 individuals with a mean age of 15.15 ± 2.04 years and a mean compliance rate with physical therapy of 80.2 ± 11.8%. Bivariate analysis revealed Hispanic/Latino patients were more likely to cancel/no show (18 ± 22.82) than non-Hispanic/Latino patients (7.55 ± 6.88, p = 0.010). Logistic regression revealed patients were significantly less likely to attend 85% of rehabilitation visits if in single-parent households ( p = 0.024). The interaction of insurance type and residence stability (maintaining a single residence during treatment) found patients with public insurance and stable housing were less likely to reach the 85% compliance threshold (Table 1). At trend level, linear regression revealed an inverse relationship with distance and physical therapy attendance ( p = 0.082), in addition to linear regression showing unstable residence ( p = 0.052) and public insurance ( p = 0.067) as significant at trend level of patients not reaching 85% compliance. Conclusion: Our study revealed single-parent households and Hispanic/Latino patients were significantly correlated with lower rehabilitation adherence, in addition to trends showing distance to physical therapy, unstable housing, and public insurance correlated with lower compliance. Our work highlights potential predictors of rehabilitation noncompliance and allows for targeted efforts to increase adherence in patients with these factors. [Table: see text]

Sloths are canopy-dwelling inhabitants of American neotropical rainforests that exhibit suspensory behaviors. These abilities require both strength and muscular endurance to hang for extended periods of time; however, the skeletal muscle mass of sloths is reduced, thus requiring modifications to muscle architecture and leverage for large joint torque. We hypothesize that intrinsic muscle properties are also modified for fatigue resistance and predict a heterogeneous expression of slow/fast myosin heavy chain (MHC) fibers that utilize oxidative metabolic pathways for economic force production. MHC fiber type distribution and energy metabolism in the forelimb muscles of three-toed ( Bradypus variegatus, n = 5) and two-toed ( Choloepus hoffmanni, n = 4) sloths were evaluated using SDS-PAGE, immunohistochemistry, and enzyme activity assays. The results partially support our hypothesis by a primary expression of the slow MHC-1 isoform as well as moderate expression of fast MHC-2A fibers, whereas few hybrid MHC-1/2A fibers were found in both species. MHC-1 fibers were larger in cross-sectional area (CSA) than MHC-2A fibers and comprised the greatest percentage of CSA in each muscle sampled. Enzyme assays showed elevated activity for the anaerobic enzymes creatine kinase and lactate dehydrogenase compared with low activity for aerobic markers citrate synthase and 3-hydroxyacetyl CoA dehydrogenase. These findings suggest that sloth forelimb muscles may rely heavily on rapid ATP resynthesis pathways, and lactate accumulation may be beneficial. The intrinsic properties observed match well with suspensory requirements, and these modifications may have further evolved in unison with low metabolism and slow movement patterns as means to systemically conserve energy. NEW & NOTEWORTHY Myosin heavy chain (MHC) fiber type and fiber metabolic properties were evaluated to understand the ability of sloths to remain suspended for extended periods without muscle fatigue. Broad distributions of large, slow MHC-1 fibers as well as small, fast MHC-2A fibers are expressed in sloth forelimbs, but muscle metabolism is generally not correlated with myosin fiber type or body size. Sloth muscles rely on rapid, anaerobic pathways to resist fatigue and sustain force production.

Deep vein thrombosis (DVT) is a common disease that carries serious ramifications for patients, including pulmonary embolism and post-thrombotic syndrome (PTS). Although standard treatment for DVT is anticoagulation, this carries an added risk of bleeding and increased medication monitoring. Identifying those at risk for DVT and PTS can be difficult, and current research with murine models is helping to illuminate the biologic changes associated with these two disorders. Potential novel biomarkers for improving the diagnosis of DVT and PTS include ICAM-1, P-selectin, and cell-free DNA. Inhibition of factor XI, P- and E-selectin, and neutrophil extracellular traps holds promise for novel clinical treatment of DVT. Experimental research on PTS suggests potential cellular and mediator therapy targets of TLR9, MMP-2 and-9, PAI-1, and IL-6. Although many important concepts and mechanisms have been elucidated through research on DVT and PTS, more work must be done to translate experimental findings to the clinical arena. This review examines the currently used murine models of DVT, biomarkers involved in the pathophysiology and diagnosis of DVT and PTS, and potential pharmacologic targets for PTS treatment.

Importance With the stabilization of breast cancer incidence and substantial improvement in survival, more attention has focused on postmastectomy breast reconstruction (PBR). Despite its demonstrated benefits, wide disparities in the use of PBR remain. Physician-patient communication has an important role in disparities in health care, especially for elective surgical procedures. Recognizing this, the State of New York enacted Public Health Law (NY PBH Law) 2803-o in 2011 mandating that physicians communicate about reconstructive surgery with patients undergoing mastectomy. Objective To evaluate whether mandated physician-patient communication is associated with reduced racial/ethnic disparities in immediate PBR (IPBR). Design, Setting, and Participants This retrospective study used state inpatient data from January 1, 2008, through December 31, 2011, in New York and California to evaluate a final sample of 42 346 women aged 20 to 70 years, including 19 364 from New York (treatment group) and 22 982 from California (comparison group). The primary hypothesis tested the effect of the New York law on racial/ethnic disparities, using California as a comparator. The National Academy of Medicine’s (formerly Institute of Medicine) definition of a disparity was applied, and a difference-in-differences method (before-and-after comparison design) was used to evaluate the association of NY PBH Law 2803-o mandating physician-patient communication with disparities in IPBR. Data were analyzed from July 1, 2016, to February 24, 2017. Exposures New York PBH Law 2803-o was implemented on January 1, 2011. The preexposure period included January 1, 2008, through December 31, 2010 (3 years); the postexposure period, January 1 through December 31, 2011 (1 year). Main Outcomes and Measures The primary outcome was use of IPBR among white, African American, Hispanic, and other minority groups before and after the implementation of NY PBH Law 2803-o. Results Among the 42 346 women (mean [SD] age, 53 [10] years), 65.3% (27 654) were white, 12.7% (5365) were Hispanic, 9.4% (3976) were African American, and 12.6% (5351) were other minorities. The new legislation was not associated with the overall IPBR rate or disparity in IPBR between whites and African Americans (reduction of 1 percentage point; 95% CI, −0.02 to 0.04), but it was associated with a reduction in disparities in IPBR between Hispanic and white patients by 9 (95% CI, 0.06-0.11) percentage points and between other minorities and white patients by 13 (95% CI, 0.11-0.16) percentage points. Conclusions and Relevance Physician-patient communication may help to address inequity in the use of elective surgical procedures, such as IPBR. However, lack of patient trust and/or effective physician-patient communication may reduce the potential effect of mandatory communication for some subpopulations, including African American individuals.