Interest in spatial ability has grown over the past few decades following the emergence of correlational evidence associating spatial aptitude with educational performance in the fields of science, technology, engineering, and mathematics. The research field at large and the anatomy education literature on this topic are mixed. In an attempt to generate consensus, a meta‐analysis was performed to objectively summarize the effects of spatial ability on anatomy assessment performance across multiple studies and populations. Relevant studies published within the past 50 years (1969–2019) were retrieved from eight databases. Study eligibility screening was followed by a full‐text review and data extraction. Use of the Mental Rotations Test (MRT) was required for study inclusion. Out of 2,450 screened records, 15 studies were meta‐analyzed. Seventy‐three percent of studies (11 of 15) were from the United States and Canada, and the majority (9 of 15) studied professional students. Across 15 studies and 1,245 participants, spatial ability was weakly associated with anatomy performance (rpooled = 0.240; CI at 95% = 0.09, 0.38; P = 0.002). Performance on spatial and relationship‐based assessments (i.e., practical assessments and drawing tasks) was correlated with spatial ability, while performance on assessments utilizing non‐spatial multiple‐choice items was not correlated with spatial ability. A significant sex difference was also observed, wherein males outperformed females on spatial ability tasks. Given the role of spatial reasoning in learning anatomy, educators are encouraged to consider curriculum delivery modifications and a comprehensive assessment strategy so as not to disadvantage individuals with low spatial ability.

Recent research has found that individuals can selectively forget a subset of items through directed forgetting. The goal of the present study was to replicate this selective directed forgetting effect and elucidate its underlying mechanisms. Unfortunately, results from four experiments failed to find any evidence of selective directed forgetting. Participants failed to forget any items when instructed to forget a subset of items from a first list before learning a second list. Participants were only successful in forgetting items from the first list when they were instructed to forget all items from the first list before learning the second list.

Osteoporosis presents a challenge for successful implant fixation due to an impaired healing response. Preclinical studies have consistently reported reduced osseointegration capability in trabecular bone. Although clinical studies of implant success in dentistry have not found a negative effect due to osteoporosis, low bone mass is a significant risk factor for implant migration in orthopedics. Pharmacologic treatment options that limit bone resorption or upregulate formation have been studied preclinically. While, both treatment options improve implant fixation, direct comparisons to-date have found anti-catabolic more effective than anabolic treatments for establishing implant fixation, but combination approaches are better than either treatment alone. Clinically, anti-catabolic treatments, particularly bisphosphonates have been shown to increase the longevity of implants, while limited clinical evidence on the effects of anabolic treatment exists. Preclinical experiments are needed to determine the effects of osteoporosis and subsequent treatment on the long-term maintenance of fixation and recovery after bone loss.

We completed a systematic literature review of in vivo animal models that use arthrotomy-based methods to study particle-induced peri-implant osteolysis. The purpose of the review was to characterize the models developed to date, to determine the questions addressed, to assess scientific rigor and transparency and to identify gaps in knowledge. We probed three literature databases (Medline, Embase and Scopus) and found 77 manuscripts that fit the search parameters. In the most recent 10 years, researchers mainly used rat and mouse models, whereas in the previous 20 years large animal, canine and rabbit models were more common. The studies have demonstrated several pathophysiology pathways, including macrophage migration, particle phagocytosis, increased local production of cytokines and lysosomal enzymes, elevated bone resorption and suppressed bone formation. The effect of variation in particle characteristics and concentration received limited attention with somewhat mixed findings. Particle contamination by endotoxin was shown to exacerbate peri-implant osteolysis. The possibility of early diagnosis was demonstrated through imaging and biomarker approaches. Several studies showed that both local and systemic delivery of bisphosphonates inhibits the development of particle-induced osteolysis. Other methods of inhibiting osteolysis include the use of anabolic agents and altering the implant design. Few studies examined non-surgical rescue of loosened implants, with conflicting results with alendronate. We found that the manuscripts often lacked the methodological detail now advocated by the ARRIVE guidelines, suggesting that improvement in reporting would be useful to maximize rigor and transparency.

Biomarkers are of interest to identify patients at risk for peri‐implant osteolysis and aseptic loosening. We used a rat model of particle‐induced peri‐implant osteolysis to investigate if early changes in biomarkers were associated with subsequent implant fixation strength. Implants were placed in rat femora, which were then challenged with intra‐articular knee injections of either clean polyethylene, lipopolysaccharide‐doped polyethylene, or cobalt‐chromium alloy particles, with particle‐free vehicle serving as control (n ≥ 8 per group). Rats were weighed weekly, blood was collected at weeks 0, 3, 5, and 6, and locomotor behavior was assessed 4 days before study conclusion. Rats were euthanized 6 weeks post surgery. Week 6 serum was analyzed for five bone remodeling markers, while longitudinal serum was assessed for osteocalcin. Bone‐implant contact, peri‐implant trabecular architecture, and implant fixation strength were measured. Rats challenged with cobalt‐chromium particles had a significant reduction in implant fixation strength compared with the vehicle‐control group (P = .034). This group also had elevated serum osteocalcin (P = .005), depressed weight gain (P = .001) and less frequent rearing behavior (P = .029). Regardless of group, change in serum osteocalcin at week 3 (r = −.368; P = .046), change in weight at week 2 (r = .586; P < .001), as well as weight change at all other time intervals were associated with fixation strength. The finding that early alterations in serum osteocalcin and body weight were predictive of subsequent implant fixation strength supports continued investigation of biomarkers for early detection of peri‐implant osteolysis and implant loosening. Further, change in biomarker levels was found to be more indicative of implant fixation status than any single measurement.

Particles released from implants cause inflammatory bone loss, which is a key factor in aseptic loosening, the most common reason for joint replacement failure. With the anticipated increased incidence of total joint replacement in the next decade, implant failure will continue to burden patients. The gut microbiome is increasingly recognized as an important factor in bone physiology, however, its role in implant loosening is currently unknown. We tested the hypothesis that implant loosening is associated with changes in the gut microbiota in a preclinical model. When the particle challenge caused local joint inflammation, decreased peri-implant bone volume, and decreased implant fixation, the gut microbiota was affected. When the particle challenge did not cause this triad of local effects, the gut microbiota was not affected. Our results suggest that cross-talk between these compartments is a previously unrecognized mechanism of failure following total joint replacement. K E Y W O R D S bone volume, gut microbiome, implant, implant fixation, orthopedics | 14303 MORAN et Al. Vehicle Yes No 12 10 LPS-PE Yes Yes (LPS-doped PE) 12 12 Total 61 Experiment 3 Naïve No No 12 10 Vehicle Yes No 12 10 CoCr Yes Yes (CoCr) 12 11

Rationale Spatial ability has been defined theoretically as ‘the ability to make use of simulated mental imagery (often in conjunction with currently perceived images) to solve problems'. Despite being among the most investigated factors of human cognitive functioning, spatial ability has been relegated to a secondary status within human intelligence research due to inconsistent evidence supporting spatial skills as predictors for educational success. Recently, however, interest in spatial ability within the anatomical community has grown, due to correlational evidence associating spatial aptitude with educational performance in the areas of science, technology, engineering, and mathematics. As a result, a substantial volume of contemporary research has focused on further uncovering the role that spatial ability plays in anatomical knowledge acquisition and retention. As such, this current study utilized a systematic review (to be followed by a meta‐analysis) to identify the extent to which spatial ability affects performance in anatomy. Methods Relevant studies published within the past 50 years (2019–1969) were searched for across eight databases. Predetermined eligibility criteria were applied to the screening of titles and abstracts to discern their appropriateness for study inclusion. Study outcomes were first thematically analyzed (reported herein) and will be followed by a true meta‐analysis. Results A total of 2,458 records were screened, 59 underwent full‐text review, and 21 studies (k) were included for final analysis. Of these studies, 57% (12 of 21) were from North America, most (15 of 21) studied graduate/professional students, and all were published in 2000 or later, except for one study from 1985. Most studies (71%; 15 of 21) evaluated the association between spatial ability and anatomy performance using the Mental Rotations Test (k=14) and some form of a practical assessment of anatomical knowledge (k=15). Of the 15 correlational studies 6, 7, and 2 reported significant, non‐significant, and inconclusive findings respectively. The prevalence of conflicting studies further necessitates the need for a meta‐analysis, which is currently underway. Conclusions High spatial ability is often associated with better scores in anatomy, but some studies show no association. In the absence of a meta‐analysis, it is challenging to interpret the literature to determine the significance of practical implications, such as providing students with different study techniques or presentation modalities depending on their level of spatial ability. Only a meta‐analysis will better inform our understanding of the current literature.

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