Two-year minimum survivorship and radiographic analysis of a pressfit short humeral stem for total shoulder arthroplasty.

Background: Newer generation humeral stem designs in total shoulder arthroplasty (TSA) are trending towards shorter lengths and uncemented fixation. The goal of this study is to report a 2-yr minimum clinical and radiographic outcomes of an uncemented short-stem press-fit humeral stem in anatomic total shoulder arthroplasty (ATSA) and reverse total shoulder arthroplasty (RTSA). Methods: A retrospective multicenter database review was performed of all patients who received an uncemented short-length press-fit humeral stem (Equinoxe Preserve humeral stem, Exactech, Inc., Gainesville, FL, USA) in ATSA and RTSA with a minimum two-year follow-up. The primary outcome was the prevalence of humeral stems at risk of radiographic loosening. Secondary outcomes included evaluation of functional outcome scores and prevalence of revision TSA for humeral stem loosening. Two blinded observers performed radiographic analyses, which included humeral stem alignment, canal filling ratio, radiolucent lines, stress shielding (calcar and greater tuberosity), and changes in component position (subsidence and stem shift). At risk stems were defined by the presence of one or more of the following: humeral stem with shifting or subsidence, scalloping of the humeral cortex, or radiolucent lines measuring 2 mm or greater in 3 or more zones. Results: 287 patients (97 ATSA and 190 RTSA) were included in this study. The mean follow-up was 35.9 (±6.1) months. There were significant improvements for all functional outcome scores (P < .05), range of motion (P < .05), and visual analogue pain scale pain (P < .05). The prevalence of humeral stem at risk of radiographic loosening was 1% in the ATSA group (1/97) and 18.4% in the RTSA group (35/190). Calcar resorption was seen in 34% of ATSA and 19% of RTSA, with severe resorption in 12.4% of ATSA and only 3.2% of RTSA. Greater tuberosity resorption was present in 3.1% of ATSA and 7.9% of RTSA. The mean canal filling ratio was 50.2% (standard deviation 11.2%). Using logistic regression, a significant positive correlation between canal filling ratio and stress shielding (P < .01) was seen for both calcar and tuberosity stress shielding. The revision surgery rate was 0% in ATSA compared to 1.6% in RTSA. Conclusion: This retrospective study demonstrates a low revision rate and low prevalence of humeral stems at risk of radiographic loosening at two years with a press-fit short-stem humeral design in ATSA. Physiologic subsidence of humeral stems can account for higher prevalence of humeral stems at radiographic risk of loosening in RTSA compared to ATSA.

Adaptive ecological knowledge among the Ndjuka Maroons of French Guiana; a case study of two 'invasive species': Melaleuca quinquenervia and Acacia mangium.

BACKGROUND: To understand how local ecological knowledge changes and adapts, here in the case of the recent introduction of plant species, we report the knowledge and perceptions of the Ndjuka (Maroon) of French Guiana concerning two tree species, Acacia mangium and niaouli (Melaleuca quinquenervia), which are categorized as "invasive alien plants" in the savannas of their territory. METHODS: To this end, semi-structured interviews were conducted between April and July 2022, using a pre-designed questionnaire, plant samples and photographs. The uses, local ecological knowledge, and representations of these species were surveyed among populations of Maroon origin in western French Guiana. All responses to closed questions collected during the field survey were compiled into an Excel spreadsheet in order to perform quantitative analyses, including the calculation of use reports (URs). RESULTS: It appears that the local populations have integrated these two plant species, which are named, used and even traded, into their knowledge systems. On the other hand, neither foreignness nor invasiveness seem to be relevant concepts in the perspective of the informants. The usefulness of these plants is the determining factor of their integration into the Ndjuka medicinal flora, thus resulting in the adaptation of their local ecological knowledge. CONCLUSION: In addition to highlighting the need for the integration of the discourse of local stakeholders into the management of "invasive alien species," this study also allows us to observe the forms of adaptation that are set in motion by the arrival of a new species, particularly within populations that are themselves the result of recent migrations. Our results furthermore indicate that such adaptations of local ecological knowledge can occur very quickly.

Two-year clinical outcomes and complication rates in anatomic and reverse shoulder arthroplasty implanted with Exactech GPS intraoperative navigation.

INTRODUCTION: We compared the 2-year clinical outcomes of both anatomic and reverse total shoulder arthroplasty (ATSA and RTSA) using intraoperative navigation compared to traditional positioning techniques. We also examined the effect of glenoid implant retroversion on clinical outcomes. HYPOTHESIS: In both ATSA and RTSA, computer navigation would be associated with equal or better outcomes with fewer complications. Final glenoid version and degree of correction would not show outcome differences. MATERIAL AND METHODS: A total of 216 ATSAs and 533 RTSAs were performed using preoperative planning and intraoperative navigation with a minimum of 2-year follow-up. Matched cohorts (2:1) for age, gender, and follow-up for cases without intraoperative navigation were compared using all standard shoulder arthroplasty clinical outcome metrics. Two subanalyses were performed on navigated cases comparing glenoids positioned greater or less than 10° of retroversion and glenoids corrected more or less than 15°. RESULTS: For ASTA, no statistical differences were found between the navigated and non-navigated cohorts for postoperative complications, glenoid implant loosening, or revision rate. No significant differences were seen in any of the ATSA outcome metrics besides higher internal and external rotation in the navigated cohort. For RTSA, the navigated cohort showed an ARR of 1.7% (95% CI 0%, 3.4%) for postoperative complications and 0.7% (95% CI 0.1%, 1.2%) for dislocations. No difference was found in the revision rate, glenoid implant loosening, acromial stress fracture rates, or scapular notching. Navigated RTSA patients demonstrated significant improvements over non-navigated patients in internal rotation, external rotation, maximum lifting weight, the Simple Shoulder Test (SST), Constant, and Shoulder Arthroplasty Smart (SAS) scores. For the navigated subcohorts, ATSA cases with a higher degree of final retroversion showed significant improvement in pain, Constant, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), SST, University of California-Los Angeles shoulder score (UCLA), and Shoulder Pain and Disability Index (SPADI) scores. No significant differences were found in the RTSA subcohort. Higher degrees of version correction showed improvement in external rotation, SST, and Constant scores for ATSA and forward elevation, internal rotation, pain, SST, Constant, ASES, UCLA, SPADI, and SAS scores for RTSA. CONCLUSION: The use of intraoperative navigation shoulder arthroplasty is safe, produces at least equally good outcomes at 2 years as standard instrumentation does without any increased risk of complications. The effect of final implant position above or below 10° of glenoid retroversion and correction more or less than 15° does not negatively impact outcomes.

Short-term radiographic analysis of a stemless humeral component for anatomic total shoulder arthroplasty.

Background: Standard stemmed humeral implants have traditionally been utilized for total shoulder arthroplasty (TSA) with a recent trend to implant smaller stems including short and stemless humeral designs. However, the rate of stress shielding after stemless TSA has not been primarily studied. Therefore, the objective of this study is to report the short-term survivorship and radiographic analysis of a stemless humeral implant. Methods: A retrospective cohort review of a prospectively collected, multicenter database for patients undergoing total shoulder arthroplasty with a stemless humeral design (Equinoxe Stemless; Exactech, Inc., Gainesville, FL, USA) with a minimum of 2 years clinical and radiographic follow-up was performed. The primary outcomes were to report the location and rate of stress shielding from a radiographic analysis of the humeral stem. Additionally, the revision rate of the humeral stem is reported. The secondary outcomes included ASES scores, visual analog scale (VAS) pain scores, and range of motion (ROM). Radiographs (anterior-posterior/Grashey and axillary) were reviewed blindly by two fellowship trained shoulder surgeons. Radiographic analysis included stress shielding (partial or complete cortical resorption) and subsidence or shift in component position. Results: Fifty four patients were included in this study with an average follow-up of 27 months (range 24-32 months). The average age of this cohort was 65 years (range 57-73 years) with 23 patients (43%) being female. Stress shielding was observed in 4 patients (7%) with the medial calcar being the most common location of stress shielding. Three of the 4 patients (75%) had evidence of partial resorption while 1 patient (25%) had evidence of complete resorption. No humeral component shift or subsidence was observed. There were no revisions due to humeral component complications. There was 1 revision surgery for aseptic glenoid loosening. A significant improvement for all clinical outcome measures was seen including with respect to VAS pain, which improved from 6.2 to 1.8 (P < .05), ASES, which improved from 38.2 to 81.8 (P < .05), and ROM which forward flexion improved from 120 degrees to 153 degrees (P < .05) and external rotation improved from 29 degrees to 49 degrees (P < .05). Discussion: This ongoing study demonstrates a low rate of stress shielding for a stemless design humeral implant at short-term follow-up without any revision surgery due to humeral component complications. Longer term radiographic and clinical analysis with this cohort will be needed to confirm these findings and theoretical benefits for future revision surgeries.

Clinical outcomes of anatomic vs. reverse total shoulder arthroplasty in primary osteoarthritis with preoperative rotational stiffness and an intact rotator cuff: a case control study.

BACKGROUND: Reverse total shoulder arthroplasty (rTSA) has begun to challenge the place of anatomic total shoulder arthroplasty (aTSA) as a primary procedure for certain indications. One purported benefit of aTSA is improved postoperative range of motion (ROM) compared to rTSA especially in internal rotation; however, it is unclear whether aTSA can provide patients with significant preoperative stiffness superior ROM compared to rTSA. Our purpose was to compare clinical outcomes of aTSA and rTSA performed in stiff vs. non-stiff shoulders for rotator cuff intact (RCI) glenohumeral osteoarthritis (GHOA). METHODS: A retrospective review of an international shoulder arthroplasty database identified 1608 aTSAs and 600 rTSAs performed for RCI GHOA with minimum 2-year follow-up. Defining preoperative stiffness as ≤ 0° of passive external rotation (ER), we matched: (1) stiff aTSAs (n = 257) 1:3 to non-stiff aTSAs, (2) stiff rTSAs (n = 87) 1:3 to non-stiff rTSAs, and (3) stiff rTSAs (n = 87) 1:1 to stiff aTSAs. We compared ROM, outcome scores, and the rate of complications and revision surgery at latest follow-up. RESULTS: Despite stiff aTSAs having poorer preoperative ROM and functional outcome scores for all measures assessed (P < .001 for all), only poorer postoperative active abduction (113 ± 27° vs. 128 ± 35°; P < .001), active ER (39 ± 18° vs. 50 ± 20°; P < .001), and passive ER (45 ± 17° vs. 56 ± 18°; P < .001) persisted postoperatively compared to the non-stiff cohort. Similarly, stiff rTSAs had poorer preoperative ROM and functional outcome scores for all measures assessed compared to non-stiff rTSAs (P ≤ .044), but only poorer active abduction (108 ± 24° vs. 128 ± 29°, P < .001), active ER (28 ± 17° vs. 42 ± 17°, P < .001), and passive ER (36 ± 15° vs. 48 ± 17°, P < .001) persisted. When comparing stiff rTSAs to matched stiff aTSAs, no significant differences in preoperative ROM or functional outcome scores were found. However, stiff aTSAs had greater postoperative active internal rotation score (4.8 ± 1.5 vs. 4.2 ± 1.7, P = .022), active ER (40 ± 19° vs. 28 ± 17°, P < .001), and passive ER (46 ± 18° vs. 36 ± 15°, P = .001). Postoperative outcome scores were similar across all matched cohort comparisons despite motion differences. The rate of complications and need for revision surgery did not differ between any group comparisons. CONCLUSIONS: Patients with RCI GHOA who have preoperative rotational stiffness have poorer postoperative ROM compared with non-stiff patients following both aTSA and rTSA, but similar functional outcome scores. Notably, preoperative limitations in passive ER do not appear to be a limitation to utilizing aTSA. Indeed, patients with limited preoperative ER treated with aTSA had greater postoperative internal rotation and ER compared to those treated with rTSA.

High intraoperative accuracy and low complication rate of computer-assisted navigation of the glenoid in total shoulder arthroplasty.

BACKGROUND: Preoperative planning software with intraoperative guidance technology is increasingly being used to manage complex glenoid deformity in anatomic total shoulder arthroplasty (TSA) and reverse TSA. The aim of this study was to review the intraoperative efficacy and complications of computer-assisted navigation (CAN) surgery for the treatment of glenoid deformity in TSA. METHODS: We performed a retrospective review of all TSAs implanted using a single computer navigation shoulder system. All patients underwent preoperative planning with computed tomography-based preoperative planning software. The starting point on the glenoid and the final version and inclination of the central post (cage) of the glenoid component were reviewed on the intraoperative navigation guidance report and compared with these parameters on the preoperative plan for each patient. The intraoperative accuracy of CAN for glenoid positioning was determined by the deviation of the starting point and final position of the central cage drill in the glenoid compared with the preoperative plan. Data regarding intraoperative complications and the number of times the navigation system was abandoned intraoperatively were collected. RESULTS: A total of 16,723 anatomic TSAs and reverse TSAs performed worldwide with the aforementioned navigation system were included in this review. In 16,368 cases (98%), every step of the navigation procedure was completed without abandoning use of the system intraoperatively. There was minimal deviation in the intraoperative execution of the preoperative plan with respect to version (0.6° ± 1.96°), inclination (0.2° ± 2.04°), and the starting point on the glenoid face (1.90 ± 1.2 mm). In this cohort, 9 coracoid fractures (0.05%) were reported. CONCLUSION AND DISCUSSION: This study demonstrates the safety and efficacy of CAN for glenoid implantation in TSA. Future studies should focus on assessing the impact of CAN on the longevity and survival of glenoid components and improving the cost-effectiveness of this technology.

Migrant Pharmacopoeias: An Ethnobotanical Survey of Four Caribbean Communities in Amazonia (French Guiana).

French Guiana is an overseas French department in South America at the margin of the Amazon basin. Its population is characterized by an important number of cultural groups. Many inhabitants originate from the Caribbean (mostly Saint Lucia, Martinique, Guadeloupe, Haiti, and the Dominican Republic). The objectives of this study were to present an overview of the main uses of plants among the Caribbean populations in French Guiana, and how they contribute to the dynamics of plant-based practices, in order to provide insights into ethnobotanical convergences, divergences, and hybridizations (such as the importation of new species and associated practices, and the adoption of Amazonian species by Caribbean people). Interviews and botanical voucher collections were conducted throughout the coastal area of French Guiana. Sixteen Saint Lucian, nineteen Haitian, eighteen French Caribbean, and twelve Dominican informants were interviewed during the fieldwork. Altogether they use 212 botanical species. Some plants have recently been imported directly from the Caribbean, while adaptations have also taken place: some species that do not exist locally are abandoned while Amazonian species are integrated to form hybrid pharmacopoeias. The phytotherapies of these communities in French Guiana are still conserved as consistent sets of knowledge, although they tend to blend through an ongoing process of hybridization. Supplementary Information: The online version contains supplementary material available at 10.1007/s12231-021-09529-0.

La Guyane française est un département français d'Amérique du Sud situé à la marge nord du bassin amazonien. La composition de sa population est caractérisée par une très grande diversité d'appartenances culturelles. De nombreux habitants sont notamment originaires des Caraïbes (principalement de Sainte­Lucie, Martinique, Guadeloupe, Haïti et de la République dominicaine). Les objectifs de cette étude étaient de présenter une vue d'ensemble des principaux usages de soin par les plantes chez les populations caribéennes de Guyane française, et la manière dont ils contribuent à la dynamique des pratiques de phytothérapie locales, afin d'apporter un éclairage sur les modalités de convergences, de divergences et d'hybridations ethnobotaniques (telles que l'importation de nouvelles espèces et d'usages associés et l'adoption d'espèces amazoniennes par les migrants caribéens) auxquelles elles donnent naissance. Des entretiens et des collectes d'herbiers ont été menés sur l'ensemble de la zone côtière de la Guyane française. Seize informateurs saint­luciens, dix­neuf haïtiens, dix­huit caribéens français et douze dominicains ont été interrogés au cours du travail de terrain. Au total, ceux­ci ont mentionné utiliser 212 espèces botaniques. Certaines plantes ont récemment été directement importées des îles de la Caraïbe, et des adaptations ont également eu lieu: certaines espèces qui n'existent pas localement sont progressivement délaissées par les migrants caribéens tandis que, a contrario, des espèces amazoniennes sont intégrées à leurs pharmacopées respectives. On observe enfin que les phytothérapies de ces communautés caribéennes de Guyane française conservent un ensemble cohérent de connaissances ethnomédicinales, qui tend cependant à se mélanger dans un processus continu d'hybridation bioculturelle.

Asian elephant self-medication as a source of ethnoveterinary knowledge among Karen mahouts in northern Thailand.

ETHNOPHARMACOLOGICAL RELEVANCE: Ethnoveterinary medicine is often assumed to be a subset of human medicinal knowledge. Here we investigate the possibility that some ethnoveterinary medicine rather originates from observations of animal self-medication. We document and analyze the ethnoveterinary medicine used by Karen mahouts for elephant care and attempt to determine whether this knowledge originated from humans or elephants. MATERIALS AND METHODS: Elephant camp owners and mahouts in four communities in northern Thailand were interviewed about their knowledge and use of plants for ethnoveterinary elephant care. For each ethnoveterinary plant, data were collected on Karen human medicinal uses and whether elephants independently consume them. Based on overlaps between ethnoveterinary use, human medicinal use and elephant dietary use, plants were classified into three categories: those that originated from Karen human medicine, those that originated from Asian elephant self-medication, and those which were present in both human and elephant knowledge traditions. RESULTS: The use of 34 plants (32 identified at least to genus) and two additional non-plant remedies (salt and human urine) were reported to be used in ethnoveterinary elephant medicine. A total of 44 treatments in 11 use categories were recorded: tonic, wounds, compress, eye problems, indigestion, broken bones, galactagogue, snakebite, fatigue, skin and musth regulation. Of the ethnoveterinary plants, 55% had the same use in human medicine, 43% had different uses and 2% had no use. Elephants consume 84% of the ethnoveterinary plants as part of their natural diet. DISCUSSION: Analysis indicates that 32% of plant uses likely originated from Karen human medicine, 60% of plant uses likely existed independently in both human and elephant knowledge systems, and 8% of plant uses likely originated from elephant self-medicating behavior. The tonic use category shows the strongest evidence of influence from observations of elephant self-medication. The use of tonic medicines appears to be increasing as a way to mitigate the unnaturally limited diet of elephants in tourist camps. CONCLUSION: Ethnoveterinary medicine for elephant care is influenced by both human medicinal knowledge and elephant knowledge of plants for self-medication. The ethnoveterinary knowledge domain appears to be the result of an interactive process linked to convergent evolution or co-evolution between humans and Asian elephants.

The over-the-top subscapularis repair in reverse shoulder arthroplasty: biomechanical evaluation of a novel technique.

BACKGROUND: We evaluate the effect of repairing the upper subscapularis tendon at an alternative location on the anterior greater tuberosity above the center of rotation using a reverse shoulder arthroplasty (RSA) muscle model. METHODS: We compared an innovative subscapularis repair on the anterior aspect of the greater tuberosity with the standard repair on the lesser tuberosity in a previously validated digital linear RSA muscle model. Standard repair vs. a new repair datasets were compared for 3 RSA designs. Each model was run through humeral abduction from 0° to 140° in 2.5° increments; the resulting moment arm measurements (model of tendon efficiency) were recorded in millimeters for 3 sections (superior, middle, inferior). An isolated upper two-thirds subscapularis repair to the anterior greater tuberosity was also evaluated (the over-the-top repair). RESULTS: The new over-the-top subscapularis repair significantly increased the abduction moment arm lengths in the superior, middle, and inferior subscapularis components compared with the standard repair to the lesser tuberosity at all levels of glenohumeral abduction and for all 3 RSA designs. Repair of the upper two-thirds of the subscapularis to the new location was an abductor at a much lower level of abduction compared with the native subscapularis repair. CONCLUSION: By repairing the upper subscapularis tendon above the center of rotation (over-the-top repair) in an RSA muscle model, the subscapularis has an improved movement arm and functions as an abductor through a greater range of motion that may result in clinically increased muscle efficiency and improved strength.

Distribution of Glenoid Implant Options for Correcting Deformities Using a Preoperative Planning Tool.

Preoperative planning tools in shoulder arthroplasty are a recently developing technology with the advantage of being able to clearly assess patient anatomy and deformities before entering the OR. Addressing retroverted glenoids remains one of the most difficult aspects of primary shoulder arthroplasty. In this study, five surgeons were provided with a preoperative planning tool with posterior augmented glenoid implant options (0°, 8°, and 16°) to treat 10 cadaveric cases with a range of versions from 7.8° anteversion to 25.1° retroversion. Surgeons were able to remove less bone using 8° augmented implants over standard non-augmented implants (2.8° reamed vs. 6.4° reamed) and were able to correct each case on average within ± 1.8° of neutral version. Slight glenoid vault perforation was observed in 18% of the plans. Eight degrees posterior augmented implants were used in scans averaging 9.0° retroversion, and 16° posterior augmented implants were used in scans averaging 20.6° retroversion. Results were then compared to 14 preoperative CT scans provided by one of the surgeons in which both 8° and 16° posterior augmented glenoid implants were used in actual patients, showing 8° posterior augmented implants were used in cases averaging 12.3° retroversion, and 16° posterior augmented implants were used in cases averaging 20.7° retroversion. The study shows that surgeons can effectively and predictably use a preoperative planning tool to correct glenoid abnormalities using augmented implant solutions while minimizing both scapular bone removal and vault perforation and maximizing version correction.

Glenohumeral Anatomic Study. A Comparison of Male and Female Shoulders with Similar Average Age and BMI.

INTRODUCTION: Numerous anatomic studies of the shoulder have quantified the size, shape, and variability of either the humerus or scapula individually. However, few have attempted to quantify the relationship of the humerus to the scapula to better understand the spatial variation of these bones in both male and female shoulders. METHODS: Seventy-four cadaveric shoulder CT scans (37 males and 37 females with statistically equivalent age and BMI) were reconstructed using Mimics ® to create 3D models of the humerus and scapula. After 3D reconstruction, each CT bone model was analyzed in Rapidform® to quantify the morphology of the humerus, scapula, and the spatial relationship between the two to better understand the role of gender on the morphological variability of the glenohumeral joint. RESULTS: Spatial glenohumeral relationships of male shoulders were significantly larger than female shoulders in 13 of 16 measurements; morphology of male humeri were significantly larger than female humeri in 17 of 24 measurements, and scapula and glenoid morphology of male shoulders were significantly larger than female scapula and glenoids in 11 of 22 measurements. DISCUSSION: Numerous significant gender differences in spatial relationships and morphology were identified in this anatomic study of the glenohumeral joint. An improved understanding of these observed binomial distributions has utility for shoulder arthroplasty prosthesis design, computer navigation, and may also be useful to the orthopaedic surgeon during surgical preoperative planning.

Modeling fatigue over sleep deprivation, circadian rhythm, and caffeine with a minimal performance inhibitor model.

Sleep loss, as well as concomitant fatigue and risk, is ubiquitous in today's fast-paced society. A biomathematical model that succeeds in describing performance during extended wakefulness would have practical utility in operational environments and could help elucidate the physiological basis of sleep loss effects. Eighteen subjects (14 males, 4 females; age 25.8 +/- 4.3 years) with low levels of habitual caffeine consumption (<300 mg/day) participated. On night 1, subjects slept for 8 h (2300-0700 h), followed by 77 h of continuous wakefulness. They were assigned randomly to receive placebo or caffeine (200 mg, i.e., two sticks of Stay Alert gum) at 0100, 0300, 0500, and 0700 during nights 2, 3, and 4. The psychomotor vigilance test (PVT) was administered periodically over the 77-h period of continuous wakefulness. Statistical analysis reveals lognormality in each PVT, allowing for closed-form median calculation. An iterative parameter estimation algorithm, which takes advantage of MatLab's (R2007a) least-squares nonlinear regression, is used to estimate model parameters from subjects' PVT medians over time awake. In the model, daily periodicity is accounted for with a four-component Fourier series, and a simplified binding function describes asymptotic fatigue. The model highlights patterns in data that suggest (1) the presence of a performance inhibitor that increases and saturates over the period of continuous wakefulness, (2) competitive inhibition of this inhibitor by caffeine, (3) the persistence of an internally driven circadian rhythm of alertness, and (4) a multiplicative relationship between circadian rhythm and performance inhibition. The present inhibitor-based minimal model describes performance data in a manner consistent with known biochemical processes.