Role of bariatric surgery in reducing periprosthetic joint infections in total knee arthroplasty. A systematic review and meta-analysis.

BACKGROUND: Obesity represents an epidemic of rising numbers worldwide year after year. In the Orthopedic field, obesity is one of the major causes leading to osteoarthritis needing Total Joint Arthroplasty (TJA). Still, contextually, it represents one of the most significant risk factors for joint replacement complications and failures. So, bariatric Surgery (BS) is becoming a valuable option for weight control and mitigating obesity-related risk factors. This review of the literature and meta-analysis aims to evaluate periprosthetic joint infections (PJI) and surgical site infections (SSI) rates in patients who underwent TKA after BS compared to obese patients without BS. METHODS: Systematic review was performed according to Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines up to October 2023. We included longitudinal studies comparing obese patients who underwent total knee arthroplasty after bariatric surgery (study group) and obese patients who underwent TKA (control group). The surgical site infection and Periprosthetic joint infection rate were compared among groups using a meta-analytical approach. RESULTS: The online database and references investigation identified one hundred and twenty-five studies. PJI rate differed significantly among groups, (z = -21.8928, p < 0.0001), with a lower risk in the BS group (z = -10.3114, p < 0.0001), for SSI, instead, not statistically significance were recorded (z = -0.6784, p = 0.4975). CONCLUSIONS: The current Literature suggests that Bariatric Surgery can reduce infectious complications in TKA, leading to better outcomes and less related costs treating of knee osteoarthritis in obese patients.

Articulating spacers in elderly patients affected by periprosthetic knee infection: clinical findings and outcome.

OBJECTIVE: Although the two-stage technique is a validated strategy in periprosthetic joint infections, there is a lack of data on the patients' clinical outcomes after the spacer placement. This study aims at evaluating the quality of life, joint function, and pain in patients over 70 years affected by periprosthetic joint infection treated with a two-stage exchange using metal on polyethylene spacers. PATIENTS AND METHODS: We conducted a follow-up study to evaluate the quality of life and functionality of consecutive patients over 70 years treated for PJI at our institution using a validated assessment set including the Western Ontario and Mac Master University (WOMAC) score, Knee Society Score (KSS), numerical rating scale (NRS). Knee Range of Movement (ROM) before and after the surgery was also analyzed. RESULTS: Forty-five patients with a mean age of 76 ± 5.3 years were included. Coagulase-negative staphylococci were the most isolated microorganisms. In the preoperative study group, the WOMAC score was 48.4 ± 18.9, and the KSS objective and functional scores were 37.6 ± 17.3 and 27.6 ± 22.3, respectively. NRS was 7.3 ± 1.8. After three months of follow-up, we found better results than preoperative clinical evaluation. We retrieved similar results comparing our post-operative PROMS (WOMAC and KSS scores) with published thresholds for treatment success two months after primary total knee arthroplasty. The infection eradication rate was 87%. CONCLUSIONS: The two-stage technique confirmed its efficacy in the treatment of PJI. Patients over 70 years who had undergone the first stage of the two-stage technique for PJI showed a good quality of life and knee function.

A longitudinal study of drivers with Alzheimer disease.

OBJECTIVE: The goal of this study was to define the natural progression of driving impairment in persons who initially have very mild to mild dementia. METHODS: We studied 128 older drivers, including 84 with early Alzheimer disease (AD) and 44 age-matched control subjects without cognitive impairment. Subjects underwent repeated assessments of their cognitive, neurologic, visual, and physical function over 3 years. Self-reports of driving accidents and traffic violations were supplemented by reports from family informants and state records. Within 2 weeks of the office evaluation, subjects were examined by a professional driving instructor on a standardized road test. RESULTS: At baseline, subjects with AD had experienced more accidents and performed more poorly on the road test, compared to controls. Over time, both groups declined in driving performance on the road test, with subjects with AD declining more than controls. Survival analysis indicated that while the majority of subjects with AD passed the examination at baseline, greater severity of dementia, increased age, and lower education were associated with higher rates of failure and marginal performance. CONCLUSIONS: This study confirms previous reports of potentially hazardous driving in persons with early Alzheimer disease, but also indicates that some individuals with very mild dementia can continue to drive safely for extended periods of time. Regular follow-up assessments, however, are warranted in those individuals.

Gonadal hormones differentially modulate cocaine-induced conditioned place preference in male and female rats.

There is accumulating evidence that suggests there are sex differences in behavioral and subjective responses to cocaine. However, it is not known whether differences in cocaine reward contribute to sex differences in these responses or whether gonadal hormones affect the rewarding properties of cocaine. In the present study, conditioned place preference (CPP), a measure of non-contingent reward, was used to determine the effects of endogenous gonadal hormones and of estrogen and progesterone replacement on cocaine reward. Neurochemical measurements were also taken to identify monoaminergic substrates which underlie the behavioral phenotype. Although both intact and gonadectomized male and female rats showed a significant CPP for cocaine, ovariectomy attenuated the magnitude of CPP. These alterations coincided with a decrease in serum levels of corticosterone. In ovariectomized rats, pretreatment with progesterone inhibited cocaine CPP while estrogen plus progesterone potentiated the magnitude of CPP. Additionally, gonadectomy and ovarian hormone replacement in female rats affected serotonin/dopamine levels and turnover ratios in the ventral tegmental area and nucleus accumbens shell. While no effects of castration were observed, ovariectomy decreased levels of dopamine and serotonin in the ventral tegmental area. In females, progesterone replacement increased levels of serotonin and dopamine in the ventral tegmental area, while estrogen plus progesterone replacement increased dopamine levels in the nucleus accumbens. Collectively, these results indicate that ovarian hormones may influence cocaine reward by altering monoaminergic systems, which, in turn, may contribute to the current sex disparities in overall cocaine use.

Frequency of cocaine administration affects behavioral and endocrine responses in male and female Fischer rats.

Accumulating evidence has shown disparate behavioral responses to cocaine in male and female rats. To date, there is a lack of understanding of how cocaine administration frequency affects sexually dimorphic behavioral responses. In the present study we investigated the behavioral and endocrine responses to single (1 x 15 mg/kg) and "binge" (3 x 15 mg/kg) cocaine administration in male and female Fischer rats. Overall, females showed a more prolonged and robust behavioral response to both acute and "binge" pattern cocaine administration. Furthermore, sex-dependent behavioral topographies emerged during binge-pattern cocaine administration; female rearing activity increased across "binge" injections while ambulatory activity decreased. In contrast, male ambulatory and rearing behaviors remained constant across injections of "binge" cocaine. At the hormonal level, both single and "binge" pattern cocaine administration decreased testosterone levels in male rats. However, cocaine's modulation of testosterone levels was transient since testosterone levels were decreased by cocaine 30 min but not 3 hr following a single injection. In both male and female rats, "binge" cocaine increased plasma progesterone levels. However, acute cocaine administration increased progesterone levels transiently in only female rats. Our results show that pattern of administration affects both cocaine-stimulated behavioral and endocrine responses in male and female rats.

Recruitment mechanisms in speed and fine-direction discrimination tasks.

The minimum information necessary to specify motion requires a change in position across time. Previous studies have shown that human motion measurements improve with more than two frames of motion. This study clarifies how motion information is integrated to produce the best speed and direction discrimination. Using random-dot kinematograms, fine-direction discrimination thresholds and speed discrimination thresholds are assessed as a function of dot lifetime. Specifically, we ask if performance on both tasks depends on dot lifetime in the same manner. If both speed and direction discrimination performance improve the same way with increasing dot lifetime, this would indicate that both tasks have the same integration limit and both tasks may depend on the same underlying mechanisms. Experiment 1 shows that for both tasks a four-frame dot lifetime is necessary for observers to reach asymptotic threshold levels. The absolute level of performance improves with increasing stimulus duration or signal-to-noise ratio, but the integration limit itself does not vary. Experiment 2 examines whether this integration limit is constrained by the number of frames or by the temporal duration of the dot lifetime. The data in Experiment 2 suggest that both a minimum number of samples and a minimal temporal integration period determine the integration limit for recruitment mechanisms. The results suggest that speed and fine-direction discrimination depend upon the same underlying motion mechanisms. These results are discussed in relation to possible underlying physiological substrates and computational models of motion measurement.

The complement system of the nurse shark: hemolytic and comparative characteristics.

The complement system of the nurse shark was investigated. Six functionally pure components were isolated from a single serum sample. Sequential reactions of the components with sensitized sheep erythrocytes resulted in membrane lesions indistinguishable from the "holes" caused by guinea pig complement.