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A group of mountain climbers, caught in the dark, fights to survive their descent; An American band finds more than they bargained for in Mexico while scouting remote locations for a photo shoot; A young student's exploration into the origins of a mysterious song leads him on a winding, dangerous path through the US's deep south; A group of kids scaring each other with ghost stories discovers alarming consequences. The Best Horror of the Year showcases the previous year's best offerings in horror short fiction. This edition includes award-winning and critically acclaimed authors Mark Morris, Kaaron Warren, John Langan, Carole Johnstone, Brian Hodge, and others. For more than three decades, award-winning editor and anthologist Ellen Datlow has had her finger on the pulse of the latest and most terrifying in horror writing. Night Shade Books is proud to present the tenth volume in this annual series, a new collection of stories to keep you up at night.

Crater statistics indicate alluvial fans, crater floor, and fill/mantling deposits within impact craters >50 km in diameter in southern Margaritifer Terra were likely emplaced during multiple epochs: fans formed during the Amazonian or near the Amazonian‐Hesperian boundary, crater floor deposits are likely Hesperian in age, and most fill/mantling deposits are Amazonian. The regional distribution of fans points to a late period of widespread water‐driven degradation. Two of the final candidate landing sites for the 2011 Mars Science Laboratory mission would land on or near some of these fans, which appear younger than previously considered. Key Points Crater statistics show alluvial fans are much younger than previously thought Fans formed in the Amazonian to near the Hesperian‐Amazonian boundary Fan distribution requires a late period of regional water‐driven degradation

Spacecraft exploring Mars such as the Mars Exploration Rovers Spirit and Opportunity, as well as the Mars Science Laboratory or Curiosity rover, have accumulated evidence for wet and habitable conditions on early Mars more than 3 billion years ago. Current conditions, by contrast, are cold, extremely arid and seemingly inhospitable. To evaluate exactly how dry today's environment is, it is important to understand the ongoing current weathering processes. Here we present chemical weathering rates determined for Mars. We use the oxidation of iron in stony meteorites investigated by the Mars Exploration Rover Opportunity at Meridiani Planum. Their maximum exposure age is constrained by the formation of Victoria crater and their minimum age by erosion of the meteorites. The chemical weathering rates thus derived are ∼1 to 4 orders of magnitude slower than that of similar meteorites found in Antarctica where the slowest rates are observed on Earth.

A suite of sinuous ridges with branching and braided morphologies forms an anastomosing network in southern Argyre Planitia, Mars. Several modes of origin have been proposed for the Argyre ridges. Imagery from the High Resolution Imaging Science Experiment (HiRISE) and Context Camera (CTX) aboard Mars Reconnaissance Orbiter (MRO) and Mars Orbiter Laser Altimeter (MOLA) topographic data sets from Mars Global Surveyor (MGS) are used to constrain processes involved in formation of the Argyre ridges. We find the characteristics of the ridges and associated layered deposits consistent with glaciofluvial‐lacustrine processes and conclude that the ridges are most likely eskers. In particular, variations in ridge height appear to be related to the surrounding surface slope; ridge height increases with descending slopes and decreases with ascending slopes. This characteristic is observed in terrestrial eskers and is related to subice flow processes. The nature of some eroding beds in the ridges suggests induration. If the Argyre ridges are indeed eskers, the southern Argyre basin was once covered by the margin of a large, thick, stagnating or retreating ice deposit that extended for hundreds of kilometers or more. During ridge formation, water flowed on top, within, or beneath the ice deposit; the continuity and preservation of the ridges suggests that flow was primarily at the base of the ice. The dimensions (up to hundreds of meters tall and several kilometers wide), aspect ratio, and extent (hundreds of kilometers) of the ridges, as well as preliminary calculations of discharge, suggest that a significant amount of water was available.

Background: Open spina bifida is the most complex congenital abnormality compatible with long-term survival. This report outlines the 20- to 25-year outcome for our original cohort of patients with a myelomeningocele treated in a nonselective, prospective manner. Methods: Of the initial 118 children, 71 patients were available for our most recent review. Nineteen patients have been lost to follow-up and 28 patients have died. Data were collected on: motor level, shunt status, education/employment, seizure history, mobility, bladder/bowel continence, tethered cord, scoliosis, latex allergy, posterior cervical decompression, tracheostomy and/or gastrostomy tube. Results: Mortality (24%) continues to climb into young adulthood. Eighty-six percent of the cohort have cerebrospinal fluid diversion, with 95% having undergone at least one shunt revision. Thirty-two percent have undergone a tethered cord release, with 97% having an improvement or stabilization in their preoperative symptoms. Forty-nine percent have scoliosis, with 43% eventually requiring a spinal fusion. Sixteen patients (23%) have had at least one seizure. Eighty-five percent are attending or have graduated from high school and/or college. More than 80% of young adults have social bladder continence. Approximately 1/3 of patients are allergic to latex, with 6 patients having experienced a life-threatening reaction. Conclusion: At least 75% of children born with a myelomeningocele can be expected to reach their early adult years. Late deterioration is common. One of the greatest challenges in medicine today is establishing a network of care for these adults with spina bifida.

Purpose Subchondroplasty® is a novel minimally invasive procedure for painful subchondral bone marrow lesions (BMLs). The aim of this systematic review was to characterize the clinical outcomes of the Subchondroplasty® procedure, a novel minimally invasive procedure for the treatment of BMLs. The hypothesis tested was that patients experience improvements in pain and functional outcomes following the Subchondroplasty® procedure. Methods MEDLINE, Embase, Web of Science, and Clinicaltrials.gov were searched from database inception to search date (June 10, 2020) for all clinical studies which discussed Subchondroplasty®. Two reviewers independently screened 45 unique results and 17 studies were included in the final analysis. Data were collected regarding patient demographics, indications, pain, functional scores, conversion to TKA, and complications of the procedure. Results All but one study were level IV evidence; the mean MINORS score was 9 ± 2. There were 756 patients included, 45.1% were female, and the mean age was 54 years (range 20–85). Thirteen studies investigated the effect Subchondroplasty® to the knee, while four studied the impact on the foot and ankle. Median length of follow-up was 12 months. The most common indication for Subchondroplasty® was joint pain with corresponding BML. Major contraindications to Subchondroplasty® included severe OA, joint instability, and malalignment. Mean pain score on visual analogue scale (VAS) prior to Subchondroplasty® was 7.8 ± 0.6, but decreased to 3.4 ± 0.7 postoperatively. All studies investigating functional scores reported improvement following Subchondroplasty® (IKDC 31.7 ± 1.9–54.0 ± 4.2 and KOOS 38.1 ± 0.6–70.0 ± 4.1). There were consistently high levels of patient satisfaction; 87 ± 8% of patients would be willing to undergo the procedure again. Seven cases of complications were reported, most seriously osteomyelitis and avascular necrosis. Conversion to knee arthroplasty ranged from 12.5 to 30% with length of follow-up ranging from 10 months to 7 years. Conclusions Existing low-quality studies show Subchondroplasty® to benefit patients with BMLs through reduction in pain and improvement in function, along with a high degree of satisfaction following the procedure. The low short-to-medium term conversion rate to arthroplasty suggests that Subchondroplasty® may play a role in delaying more invasive and expensive procedures in patients with BMLs. Subchondroplasty® is a novel procedure that has promising initial findings, but requires further high-quality, comparative studies with long-term follow-up to better understand the outcomes of the procedure and impact clinical practice recommendations. Level of evidence Systematic Review of Level III and IV Studies, Level IV.

Differences in gait with age or knee osteoarthritis have been demonstrated in laboratory studies using optical motion capture (MoCap). While MoCap is accurate and reliable, it is impractical for assessment outside the laboratory. Inertial measurement units (IMUs) may be useful in these situations. Before IMUs are used as a surrogate for MoCap, methods that are reliable, repeatable, and that calculate metrics at similar accuracy to MoCap must be demonstrated. The purpose of this study was to compare spatiotemporal gait parameters and knee range of motion calculated via MoCap to IMU-derived variables and to compare the ability of these tools to discriminate between groups. MoCap and IMU data were collected from young, older, and adults with knee osteoarthritis during overground walking at three self-selected speeds. Walking velocity, stride length, cadence, percent of gait cycle in stance, and sagittal knee range of motion were calculated and compared between tools (MoCap and IMU), between participant groups, and across speed. There were no significant differences between MoCap and IMU outcomes, and root mean square error between tools was ≤0.05 m/s for walking velocity, ≤0.07 m for stride length, ≤0.5 strides/min for cadence, ≤5% for percent of gait cycle in stance, and ≤1.5° for knee range of motion. No interactions were present, suggesting that MoCap and IMU calculated metrics similarly across groups and speeds. These results demonstrate IMUs can accurately calculate spatiotemporal variables and knee range of motion during gait in young and older, asymptomatic and knee osteoarthritis cohorts.

Background: Osteochondral allograft transplantation is an effective technique for repairing large lesions of the medial femoral condyle (MFC), but its use is limited by graft availability. Purpose/Hypothesis: The present study aimed to determine whether contralateral lateral femoral condyle (LFC) allografts can provide an acceptable surface match for posterolateral MFC lesions characteristic of classic osteochondritis dissecans (OCD). The hypothesis was that LFC and MFC allografts will provide similar surface contour matches in all 4 quadrants of the graft for posterolateral MFC lesions characteristic of OCD. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen recipient human MFCs were each size-matched to 1 ipsilateral medial and 1 contralateral LFC donor (N = 30 condyles). After a nano–computed tomography (nano-CT) scan of the native recipient condyle, a 20-mm circular osteochondral “defect” was created 1 cm posterior and 1 cm medial to the roof of the intercondylar notch (n = 10). A size-matched, random-order donor MFC or LFC plug was then harvested, transplanted, and scanned with nano-CT. Nano-CT scans were then reconstructed, registered to the initial scan of the recipient MFC, and processed in MATLAB to determine the height deviation (d RMS) between the native and donor surfaces and percentage area unacceptably (>1 mm) proud (%A proud) and sunken (%A sunk). Circumferential step-off height (h RMS) and percentage circumference unacceptably (>1 mm) proud (%C proud) and sunken (%C sunk) were measured using DragonFly software. The process was then repeated for the other allograft plug. Results: Both MFC and LFC plugs showed acceptable step-off heights in all 4 quadrants (range, 0.53-0.94 mm). Neither allograft type nor location within the defect had a significant effect on step-off height (h RMS), surface deviation (d RMS), %A proud, or %A sunk. In general, plugs were more unacceptably sunken than proud (MFC, 13.4% vs 2.4%; LFC, 13.2% vs 8.1%), although no significant differences in %C sunk were seen between allograft types or locations within the defect. In LFC plugs, %C proud in the lateral quadrant (28.0% ± 26.1%) was significantly greater compared with all other quadrants (P = .0002). Conclusion: The present study demonstrates that 20-mm contralateral LFC allografts provide an acceptable surface match for posterolateral MFC lesions characteristic of OCD. Clinical Relevance: With comparable surface matching, MFC and LFC allografts can be expected to present similar stresses on the knee joint and achieve predictably positive clinical outcomes, thus improving donor availability and reducing surgical wait times for matches.

The suture anchor and transosseous drill hole techniques for reattachment of the distal biceps tendon to the radius have been found to have similar clinical and biomechanical outcomes. However, a comparison of the cost effectiveness of these techniques is lacking. The purpose of this study was to determine whether the use of suture anchors decreases operative time enough to offset the additional cost of the implants. The records of all patients undergoing a distal biceps tendon reattachment were reviewed to determine the method of fixation, operative time, and associated surgical costs. Two surgeons used a technique of fixing the tendon directly to the bone (transosseous group), whereas 3 surgeons used suture anchors. Given the standard nature of the surgical procedure (other than the fixation technique), only the costs that differed between the 2 groups were included. Surgical center costs were obtained from the local outpatient surgical center in 2011 US dollars. Five surgeons treated 70 men (mean age, 45.9±9.2 years). Mean time from injury to surgery was 14 days. Mean operative times for the transosseous and suture anchor groups were 97.6±14.9 and 95.8±25.8 minutes, respectively (The suture anchor and transosseous drill hole techniques for reattachment of the distal biceps tendon to the radius have been found to have similar clinical and biomechanical outcomes. However, a comparison of the cost effectiveness of these techniques is lacking. The purpose of this study was to determine whether the use of suture anchors decreases operative time enough to offset the additional cost of the implants. The records of all patients undergoing a distal biceps tendon reattachment were reviewed to determine the method of fixation, operative time, and associated surgical costs. Two surgeons used a technique of fixing the tendon directly to the bone (transosseous group), whereas 3 surgeons used suture anchors. Given the standard nature of the surgical procedure (other than the fixation technique), only the costs that differed between the 2 groups were included. Surgical center costs were obtained from the local outpatient surgical center in 2011 US dollars. Five surgeons treated 70 men (mean age, 45.9±9.2 years). Mean time from injury to surgery was 14 days. Mean operative times for the transosseous and suture anchor groups were 97.6±14.9 and 95.8±25.8 minutes, respectively ( P =.74). Two anchors were used in 79% of the anchor cases. The use of anchors cost $474.33 more per patient. However, this value is sensitive to the cost of the individual anchors, intersurgeon variation in operative time, and per-minute value of saved operative time. No operative time was saved with the use of suture anchors. This cost comparison framework can be used to evaluate the balance in surgical resource use due to implant cost vs savings in operative time.