Complications Following Total Ankle Arthroplasty Versus Ankle Arthrodesis for Primary Ankle Osteoarthritis.

INTRODUCTION: There are minimal data comparing complications between ankle arthrodesis (AA) versus total ankle arthroplasty (TAR) for operative management of primary osteoarthritis (OA). This study aimed to compare outcomes following AA versus TAR for primary ankle OA using a large patient database. METHODS: Patients who received AA or TAR for primary ankle OA from 2010 to 2019 were queried from PearlDiver. Rates of common joint complications were compared at 90 days, 1 year, and 2 years postoperatively using multivariable logistic regression. RESULTS: A total of 1136 (67%) patients received AA and 584 (33%) patients underwent TAR. Patients that received AA exhibited significantly higher rates of at least one common joint complication at 90 days (19.3% vs 12.6%; odds ratio [OR] 1.69), 1 year (25.6% vs 15.0%; OR 2.00), and 2 years (26.9% vs 16.2%; OR 1.91) postoperatively. This included higher rates of adjacent fusion or osteotomy procedures, periprosthetic fractures, and hardware removal at each postoperative follow-up (all P < .05). Rates of prosthetic joint infection were comparable at 2 years postoperatively (4.3% vs 4.2%; OR 0.91). CONCLUSION: The AA cohort exhibited higher rates of postoperative joint complications in the short and medium-term, namely, subsequent fusions or osteotomies, periprosthetic fractures, and hardware removal. LEVELS OF EVIDENCE: Level III.

Reoperation Rates Following Total Ankle Arthroplasty Versus Ankle Arthrodesis for Posttraumatic Indications.

AIMS: This studied aimed to compare rates of reoperation for patients who received primary ankle arthrodesis (AA) versus total ankle replacement (TAR) for posttraumatic indications between 2010 and 2016 Q2 using a nationwide claims database. METHODS: A retrospective cohort study analyzing patients who received primary AA or TAR for posttraumatic indications was performed using PearlDiver. Reoperations assessed included prosthetic joint infection (PJI), hardware removal, adjacent joint fusion, and local open reduction internal fixation (ORIF). Multivariable logistic regression was used to compare rates of reoperations at 1 and 2 years postdischarge. RESULTS: A total of 862 (74%) patients received AA and 318 (26%) patients underwent TAR for a posttraumatic indication. At 1 year, 305 (35.4%) AA patients had at least 1 reoperation compared with 55 (17.3%) TAR patients (OR 2.32; 95% CI, 1.68-3.26). At 2 years, 364 (42.2%) AA patients and 66 (20.8%) TAR patients had at least 1 reoperation (OR 2.51; 95% CI, 1.84-3.45). ORIF, hardware removal, and adjacent joint fusions were more likely for AA patients at both time intervals (all Ps < .05). CONCLUSION: Patients who received primary AA for posttraumatic indications exhibited higher rates of major reoperations in the short to medium term compared with patients who underwent TAR. LEVELS OF EVIDENCE: Level III: Retrospective cohort study.

Rates of Operative Management for Achilles Tendon Rupture Over the Last Decade and the Influence of Gender and Age.

BACKGROUND: With emerging evidence supporting functional rehabilitation for Achilles tendon ruptures (ATRs), this study sought to evaluate the treatment trends for patients sustaining an acute ATR and whether gender and age may influence the rates of operative repair. METHODS: A retrospective database review identified ATRs from 2010 through 2019. Patients were then stratified into three cohorts based on age (18-30, 30-45, and 46 and older), separated by gender, and then assessed whether patients were treated operatively or not. Cochran-Armitage Trend test was performed to analyze the trends of operative management. Chi-square analyses were performed to assess whether the proportion of patients who received operative management in each age cohort differed from 2010 to 2019. Logistic regression analyses were performed to assess whether gender influenced treatment. RESULTS: Over the previous decade, the total rates of operative treatment for ATR significantly decreased (18.3%-12.3%, P < .0001). Each individual age cohort experienced a proportional decrease in operative management when comparing 2010 with 2019 (all P < .0001). Within all age cohorts, males were significantly more likely to receive operative treatment for an ATR over the previous decade (odds ratios: 2.63-3.22). Conclusion. Overall rates of operative management for ATR decreased across all cohorts likely due to previous studies providing evidence of similar results between operative and nonoperative managements. Over the previous decade, males were demonstrated to be far more likely than females to undergo operative management. Why females are less likely to receive an operation for ATR is likely multi-factorial and requires further exploration. LEVEL OF EVIDENCE: Level III: Retrospective comparative study.

Effects of Sodium Bicarbonate Supplementation on Muscular Strength and Endurance: A Systematic Review and Meta-analysis.

BACKGROUND: The effects of sodium bicarbonate on muscular strength and muscular endurance are commonly acknowledged as unclear due to the contrasting evidence on the topic. OBJECTIVE: To conduct a systematic review and meta-analysis of studies exploring the acute effects of sodium bicarbonate supplementation on muscular strength and endurance. METHODS: A search for studies was performed using five databases. Meta-analyses of standardized mean differences (SMDs) were performed using a random-effects model to determine the effects of sodium bicarbonate supplementation on muscular strength (assessed by changes in peak force [N], peak torque [N m], or maximum load lifted [kg]) and muscular endurance (assessed by changes in the number of repetitions performed, isokinetic total work, or time to maintain isometric force production). Subgroup meta-analyses were conducted for the muscular endurance of small vs. large muscle groups and muscular strength tested in a rested vs. fatigued state. A random-effects meta-regression analysis was used to explore possible trends in the effects of: (a) timing of sodium bicarbonate ingestion; and (b) acute increase in blood bicarbonate concentration (from baseline to pre-exercise), on muscular endurance and muscular strength. RESULTS: Thirteen studies explored the effects of sodium bicarbonate on muscular endurance and 11 on muscular strength. Sodium bicarbonate supplementation was found to be ergogenic for muscular endurance (SMD = 0.37; 95% confidence interval [CI]: 0.15, 0.59; p = 0.001). The performance-enhancing effects of sodium bicarbonate were significant for both small (SMD = 0.31; 95% CI: 0.04, 0.59; p = 0.025) and large muscle groups (SMD = 0.40; 95% CI: 0.13, 0.66; p = 0.003). Sodium bicarbonate ingestion was not found to enhance muscular strength (SMD = - 0.03; 95% CI: - 0.18, 0.12; p = 0.725). No significant effects were found regardless of whether the testing was carried out in a rested (SMD = 0.02; 95% CI: - 0.09, 0.13; p = 0.694) or fatigued (SMD = - 0.16; 95% CI: - 0.59, 0.28; p = 0.483) state. No significant linear trends in the effects of timing of sodium bicarbonate ingestion or acute increase in blood bicarbonate concentrations on muscular endurance or muscular strength were found. CONCLUSIONS: Overall, sodium bicarbonate supplementation acutely improves muscular endurance of small and large muscle groups, but no significant ergogenic effect on muscular strength was found.

Muscle oxygenation maintained during repeated-sprints despite inspiratory muscle loading.

A high work of breathing can compromise limb oxygen delivery during sustained high-intensity exercise. However, it is unclear if the same is true for intermittent sprint exercise. This project examined the effect of adding an inspiratory load on locomotor muscle tissue reoxygenation during repeated-sprint exercise. Ten healthy males completed three experiment sessions of ten 10-s sprints, separated by 30-s of passive rest on a cycle ergometer. The first two sessions were "all-out' efforts performed without (CTRL) or with inspiratory loading (INSP) in a randomised and counterbalanced order. The third experiment session (MATCH) consisted of ten 10-s work-matched intervals. Tissue saturation index (TSI) and deoxy-haemoglobin (HHb) of the vastus lateralis and sixth intercostal space was monitored with near-infrared spectroscopy. Vastus lateralis reoxygenation (ΔReoxy) was calculated as the difference from peak HHb (sprint) to nadir HHb (recovery). Total mechanical work completed was similar between INSP and CTRL (effect size: -0.18, 90% confidence limit ±0.43), and differences in vastus lateralis TSI during the sprint (-0.01 ±0.33) and recovery (-0.08 ±0.50) phases were unclear. There was also no meaningful difference in ΔReoxy (0.21 ±0.37). Intercostal HHb was higher in the INSP session compared to CTRL (0.42 ±0.34), whilst the difference was unclear for TSI (-0.01 ±0.33). During MATCH exercise, differences in vastus lateralis TSI were unclear compared to INSP for both sprint (0.10 ±0.30) and recovery (-0.09 ±0.48) phases, and there was no meaningful difference in ΔReoxy (-0.25 ±0.55). Intercostal TSI was higher during MATCH compared to INSP (0.95 ±0.53), whereas HHb was lower (-1.09 ±0.33). The lack of difference in ΔReoxy between INSP and CTRL suggests that for intermittent sprint exercise, the metabolic O2 demands of both the respiratory and locomotor muscles can be met. Additionally, the similarity of the MATCH suggests that ΔReoxy was maximal in all exercise conditions.

Respiratory muscle oxygenation is not impacted by hypoxia during repeated-sprint exercise.

This study aimed to investigate whether exercise hyperpnoea contributes to an impairment of locomotor muscle oxygenation and performance during repeated-sprint exercise in normoxia and hypoxia. Subjects performed ten 10-s sprints, separated by 30 s of passive rest while breathing either a normoxic (21% O2) or hypoxic (15% O2) gas mixture. Muscle oxygenation of the vastus lateralis and intercostal muscles was examined with near-infrared spectroscopy. Sprint and recovery vastus lateralis deoxyhaemoglobin was elevated in hypoxia by 9.2% (90% confidence interval 0.2 to 18.0) and 14.1% (90% CL 4.9 to 23.3%) compared to normoxia, respectively. There were no clear differences in respiratory muscle deoxyhaemoglobin (-0.1%, 90% CL -2.9 to 0.9%) or oxyhaemoglobin (0.9%, 90% CL -0.8 to 2.6%) between conditions. Maintenance of respiratory muscle oxygenation may contribute to the rise of vastus lateralis deoxyhaemoglobin in hypoxia during intermittent sprint cycling. This manuscript presents data which extends the fact that oxygen competition could be a limiting factor of exercise capacity.

Variations in Hypoxia Impairs Muscle Oxygenation and Performance during Simulated Team-Sport Running.

Purpose: To quantify the effect of acute hypoxia on muscle oxygenation and power during simulated team-sport running. Methods: Seven individuals performed repeated and single sprint efforts, embedded in a simulated team-sport running protocol, on a non-motorized treadmill in normoxia (sea-level), and acute normobaric hypoxia (simulated altitudes of 2,000 and 3,000 m). Mean and peak power was quantified during all sprints and repeated sprints. Mean total work, heart rate, blood oxygen saturation, and quadriceps muscle deoxyhaemoglobin concentration (assessed via near-infrared spectroscopy) were measured over the entire protocol. A linear mixed model was used to estimate performance and physiological effects across each half of the protocol. Changes were expressed in standardized units for assessment of magnitude. Uncertainty in the changes was expressed as a 90% confidence interval and interpreted via non-clinical magnitude-based inference. Results: Mean total work was reduced at 2,000 m (-10%, 90% confidence limits ±6%) and 3,000 m (-15%, ±5%) compared with sea-level. Mean heart rate was reduced at 3,000 m compared with 2,000 m (-3, ±3 min-1) and sea-level (-3, ±3 min-1). Blood oxygen saturation was lower at 2,000 m (-8, ±3%) and 3,000 m (-15, ±2%) compared with sea-level. Sprint mean power across the entire protocol was reduced at 3,000 m compared with 2,000 m (-12%, ±3%) and sea-level (-14%, ±4%). In the second half of the protocol, sprint mean power was reduced at 3,000 m compared to 2,000 m (-6%, ±4%). Sprint mean peak power across the entire protocol was lowered at 2,000 m (-10%, ±6%) and 3,000 m (-16%, ±6%) compared with sea-level. During repeated sprints, mean peak power was lower at 2,000 m (-8%, ±7%) and 3,000 m (-8%, ±7%) compared with sea-level. In the second half of the protocol, repeated sprint mean power was reduced at 3,000 m compared to 2,000 m (-7%, ±5%) and sea-level (-9%, ±5%). Quadriceps muscle deoxyhaemoglobin concentration was lowered at 3,000 m compared to 2,000 m (-10, ±12%) and sea-level (-11, ±12%). Conclusions: Simulated team-sport running is impaired at 3,000 m compared to 2,000 m and sea-level, likely due to a higher muscle deoxygenation.

Interaction of central and peripheral factors during repeated sprints at different levels of arterial O2 saturation.

PURPOSE: To investigate the interaction between the development of peripheral locomotor muscle fatigue, muscle recruitment and performance during repeated-sprint exercise (RSE). METHOD: In a single-blind, randomised and cross-over design, ten male team-sport athletes performed two RSE (fifteen 5-s cycling sprints interspersed with 25 s of rest; power self-selected) in normoxia and in acute moderate hypoxia (FIO2 0.138). Mechanical work, total electromyographic intensity (summed quadriceps electromyograms, RMSsum) and muscle (vastus lateralis) and pre-fontal cortex near-infrared spectroscopy (NIRS) parameters were calculated for every sprint. Blood lactate concentration ([Lac(-)]) was measured throughout the protocol. Peripheral quadriceps fatigue was assessed via changes in potentiated quadriceps twitch force (ΔQtw,pot) pre- versus post-exercise in response to supra-maximal magnetic femoral nerve stimulation. The central activation ratio (QCAR) was used to quantify completeness of quadriceps activation. RESULTS: Compared with normoxia, hypoxia reduced arterial oxygen saturation (-13.7%, P=0.001), quadriceps RMSsum (-13.7%, P=0.022), QCAR (-3.3%, P=0.041) and total mechanical work (-8.3%, P=0.019). However, the magnitude of quadriceps fatigue induced by RSE was similar in the two conditions (ΔQtw,pot: -53.5% and -55.1%, P=0.71). The lower cycling performance in hypoxia occurred despite similar metabolic (muscle NIRS parameters and blood [Lac(-)]) and functional (twitch and M-wave) muscle states. CONCLUSION: Results suggest that the central nervous system regulates quadriceps muscle recruitment and, thereby, performance to limit the development of muscle fatigue during intermittent, short sprints. This finding highlights the complex interaction between muscular perturbations and neural adjustments during sprint exercise, and further supports the presence of pacing during intermittent sprint exercise.

Alternativas para el estudio de los factores de riesgo del suicidio. Procedimientos metodológicos generales / Alternatives to the review of riesk factorsin suicide. General methodological procedures

Se presentan sintéticamente distintas alternativas para el estudio de los factores de riesgo del intento y el suicidio consumado. Se justifica la necesidad de estudios de este tipo en nuestro país. Se exponen las características de las investigaciones descriptivas, experimentales y analíticas, y de los estudios transversales, de cohorte y caso-control. Se recomienda el uso de estudios tipo caso-control para evaluar los factores de riesgo del suicidio. Con relación al pareamiento se plantea su propósito y se discute sobre la selección de las variables para su realización; se señalan ventajas y desventajas de la estratificación como alternativa al pareamiento. Se presentan medidas de riesgo y de asociación entre las variables estudiadas, y la significación de estas medidas en los tres tipos de estudios analíticos(AU)