Reverse total shoulder arthroplasty for proximal humerus fractures: Primary or delayed after failed treatment?

BACKGROUND

Reverse total shoulder arthroplasty (RTSA) has recently become an option for the treatment of proximal humerus fractures (PHFs) or as a salvage procedure after failure of another treatment. The purpose of this study was to compare primary RTSA with delayed RTSA in the treatment of displaced PHFs.

STUDY DESIGN & METHODS

A retrospective cohort study was conducted on patients with PHFs who were treated between May 2013 and December 2021 with primary or delayed RTSA after failure of conservative treatment or osteosynthesis. Clinical data were withdrawn from our local computerized database. Complications, active range of motion, as well as the functional outcome were recorded at the end of the follow-up period. Differences between clinical outcomes were analyzed using a logistic regression analysis.

RESULTS

A total of 70 individuals were included in this study (41 primary RTSA and 29 delayed RTSA). The mean of follow-up time was of 112 and 60 months, respectively. There were no differences between groups regarding fracture type according Neer Classification, ASA score or the presence of complications. Q-DASH and Oxford Shoulder scores were significantly better when patients underwent a primary RTSA (49.8 vs 31.4, p = 0.006 and 37.2 vs 27.5, p = 0.004 respectively). In addition, primary RTSA achieved more degrees of flexion and abduction than delayed RTSA (96.8 vs 72.9, p < 0.001 and 94.1 vs 69.3, p < 0.001 respectively).

CONCLUSION

Primary RTSA for PHFs achieved better functional outcomes and a wider range of motion when compared with delayed RTSA. However, primary and delayed RTSA have similar complication and reintervention rates.

LEVEL OF CLINICAL EVIDENCE

3.

Fossil diversity in ‘dawn’ hexapods (Diplura: Projapygoidea), with direct evidence for being chemically predaceous in the Cretaceous

Diplurans are among the earliest hexapods in the geological record. These primitively wingless relatives of insects are infrequently encountered despite being pervasive in soil habitats. Two groups have disparate adaptations for hunting, one mechanical and the other chemical, in Japygoidea and Projapygoidea, respectively. Here, we report three genera (two new) and four species of fossil Projapygidae preserved in Mesozoic and Cenozoic ambers: Electroprojapyx alchemicus gen. et sp. nov. in mid-Cretaceous Myanmar amber, and Symphylurinopsis punctatus gen. et sp. nov. and two species (unnamed) of Symphylurinus in Miocene Dominican amber. The exceptionally preserved specimens possess cerci that are morphologically specialized for expelling a glandular substance on prey. The new Cretaceous E. alchemicus is a stem group to all living species of the family and provides conclusive Mesozoic evidence for a rare type of predation involving offensive (vs. defensive) secretions. The specimen was fossilized in a preying-and-spraying position with its presumptive meal, a Symphypleona springtail (Collembola), reflecting the behavioural predatory repertoire of modern relatives. Apart from one Cenozoic species, these rare specimens represent the only fossil record of the family Projapygidae. Our findings demonstrate that these basal hexapods were predators of small arthropods of ancient forest soils and enrich our understanding of palaeoecological associations and behavioural strategies paramount for the survival of species.

Dinosaur bonebed amber from an original swamp forest soil

Dinosaur bonebeds with amber content, yet scarce, offer a superior wealth and quality of data on ancient terrestrial ecosystems. However, the preserved palaeodiversity and/or taphonomic characteristics of these exceptional localities had hitherto limited their palaeobiological potential. Here, we describe the amber from the Lower Cretaceous dinosaur bonebed of Ariño (Teruel, Spain) using a multidisciplinary approach. Amber is found in both a root layer with amber strictly in situ and a litter layer mainly composed of aerial pieces unusually rich in bioinclusions, encompassing 11 insect orders, arachnids, and a few plant and vertebrate remains, including a feather. Additional palaeontological data—charophytes, palynomorphs, ostracods— are provided. Ariño arguably represents the most prolific and palaeobiologically diverse locality in which fossiliferous amber and a dinosaur bonebed have been found in association, and the only one known where the vast majority of the palaeontological assemblage suffered no or low-grade pre-burial transport. This has unlocked unprecedentedly complete and reliable palaeoecological data out of two complementary windows of preservation—the bonebed and the amber—from the same site.

Mating and aggregative behaviors among basal hexapods in the Early Cretaceous

Among the many challenges in paleobiology is the inference and reconstruction of behaviors that rarely, if ever, leave a physical trace on the environment that is suitable for fossilization. Of particular significance are those behaviors tied to mating and courtship, individual interactions critical for species integrity and continuance, as well as those for dispersal, permitting the taxon to expand its distribution as well as access new habitats in the face of local or long-term environmental change. In this context, two recently discovered fossils from the Early Cretaceous amber of Spain (ca. 105 mya) give a detailed view of otherwise fleeting ethologies in Collembola. These occurrences are phylogenetically spaced across the class, and from species representing the two major clades of springtails-Symphypleona and Entomobryomorpha. Specifically, we report unique evidence from a symphypleonan male (Pseudosminthurides stoechus Sánchez-García & Engel, 2016) with modified antennae that may have functioned as a clasping organ for securing females during mating on water's surface, and from an aggregation of entomobryomorphan individuals (Proisotoma communis Sánchez-García & Engel, 2016) purportedly representing a swarming episode on the forest floor. We demonstrate that the mating behavioral repertoire in P. stoechus, which is associated with considerable morphological adaptations, likely implied elaborate courtship and maneuvering for guarantee sperm transfer in an epineustic species. These discoveries reveal significant behaviors consistent with modern counterparts and a generalized stasis for some ancient hexapod ethologies associated with complex mating and courtship and social or pre-social aggregations, so critical to specific constancy and dispersal.

The semi-aquatic pondweed bugs of a Cretaceous swamp

Pondweed bugs (Hemiptera: Mesoveliidae), considered a sister group to all other Gerromorpha, are exceedingly rare as fossils. Therefore, each new discovery of a fossil mesoveliid is of high interest, giving new insight into their early evolutionary history and diversity and enabling the testing of their proposed relationships. Here, we report the discovery of new mesoveliid material from Spanish Lower Cretaceous (Albian) amber, which is the first such find in Spanish amber. To date, fossil records of this family only include one species from French Kimmeridgian as compression fossils, two species in French amber (Albian-Cenomanian boundary), and one in Dominican amber (Miocene). The discovery of two males and one female described and figured as Glaesivelia pulcherrima Sánchez-García & Solórzano Kraemer gen. et sp. n., and a single female described and figured as Iberovelia quisquilia Sánchez-García & Nel, gen. et sp. n., reveals novel combinations of traits related to some genera currently in the subfamily Mesoveliinae. Brief comments about challenges facing the study of fossil mesoveliids are provided, showing the necessity for a revision of the existing phylogenetic hypotheses. Some of the specimens were studied using infrared microscopy, a promising alternative to the systematic study of organisms preserved in amber that cannot be clearly visualised. The new taxa significantly expand the fossil record of the family and shed new light on its palaeoecology. The fossils indicate that Mesoveliidae were certainly diverse by the Cretaceous and that numerous tiny cryptic species living in humid terrestrial to marginal aquatic habitats remain to be discovered. Furthermore, the finding of several specimens as syninclusions suggests aggregative behaviour, thereby representing the earliest documented evidence of such ethology.

Marsupial brood care in Cretaceous tanaidaceans

Parental care in animal evolution has long fascinated biologists, but tracing this complex of behavioural repertoires is challenging, as these transitory states often leave no corporeal traces as fossils. Among modern invertebrates, the tanaidaceans (Malacostraca: Peracarida), a lineage of marsupial crustaceans, show an interesting variety of brooding strategies. Here we report on fossil tanaidaceans from the Cretaceous of Spain and France that provide conclusive evidence for marsupial care of brood-offspring. Two exceptionally preserved female specimens of Alavatanais carabe and A. margulisae from Late Albian Peñacerrada I amber (Spain) possess four pairs of rudimentary oostegites, indicating formation of a marsupium. From Recent data, given the taxonomic distribution of a marsupium of four pairs of oostegites, we hypothesize that this may be plesiomorphic for the Tanaidomorpha. We also report on a peculiar tanaidacean specimen referable to the fossil family Alavatanaidae, Daenerytanais maieuticus gen. et sp. nov., from Early Cenomanian La Buzinie amber (France), preserved with its marsupial pouch and content. Our discoveries provide early evidence of the peracarid reproductive strategy, as seen in modern Tanaidacea, and argue that this form of parental care may have played a role in the diversification of the lineage during this period.

Histochemical changes in muscle of rats exposed subchronically to low doses of heavy metals

Heavy metals are ubiquitous in the environment and exposure through food and water as well as occupational sources can constitute a potential threat to human health. The mechanisms of heavy metal damage include the production of free radicals that alter mitochondrial activity, affecting cellular types like neurons and muscular fibres. We examined whether rats exposed subchronically via drinking water to low doses of heavy metals can produce alterations in muscle. Results showed that the proportion of ragged red fibres increased in muscle of rats exposed to lead and thallium, likewise slight changes in enzymatic activity of muscular fibres were also observed.

Aged garlic extract delays the appearance of infarct area in a cerebral ischemia model, an effect likely conditioned by the cellular antioxidant systems

Experimental evidence has shown that some garlic-derived products have a protective effect against ischemic brain injury. The present study was designed to investigate the effect of aged garlic extract (AGE), establish the therapeutic window, and determine its protective mechanism in a cerebral ischemia model. Animals were subjected to middle cerebral artery occlusion (MCAO) for 2h and treated with 1.2ml/kg body wt.(i.p.) of AGE 30min before, at the beginning of (0R), or 1h after reperfusion. The 0R treatment significantly reduced the size of the infarct area after 2h of reperfusion. Repeated doses subsequent to the 0R treatment (at 1, 2, or 3h after reperfusion) had no effect on the temporal window of protection. The protective 0R treatment with AGE prevented the increase in nitrotyrosine and the decrease in total superoxide dismutase, glutathione peroxidase, and extracellular superoxide dismutase activities induced by MCAO. These data indicate that AGE delays the effects of ischemia/reperfusion-induced neuronal injury. However, this treatment itself was not associated with a noticeable improvement in the neurological outcome, or with an effect on the inflammatory response. We conclude that the neuroprotective effect of AGE in the 0R treatment might be associated with control of the free-radical burst induced by reperfusion, preservation of antioxidant enzyme activity, and the delay of other pathophysiological processes.

Effect of clozapine on the oxygen, glucose uptake and oxidative phosphorylation of rat brain in vitro

Clozapine, a neuroleptic drug isostere of the phenothiazines, at a dose of 10(-3) M decreased the oxygen consumption of rat brain slices and homogenates. However, this effect was not potentiated when brain slices were incubated with 100 mM potassium or in a calcium-free medium, the uncoupling of brain mitochondrial oxidative phosphorylation by 10(-3) M clozapine can also be rulled out.