Orthopaedic infections: what have we learned?

Circulating levels of micronutrients and risk of osteomyelitis: a Mendelian randomization study

Background

Few observational studies have investigated the effect of micronutrients on osteomyelitis, and these findings are limited by confounding and conflicting results. Therefore, we conducted Mendelian randomization (MR) analyses to evaluate the association between blood levels of eight micronutrients (copper, selenium, zinc, vitamin B12, vitamin C, and vitamin D, vitamin B6, vitamin E) and the risk of osteomyelitis.

Methods

We performed the two-sample and multivariable Mendelian randomization (MVMR) to investigate causation, where instrument variables for the predictor (micronutrients) were derived from the summary data of micronutrients from independent cohorts of European ancestry. The outcome instrumental variables were used from the summary data of European-ancestry individuals (n = 486,484). The threshold of statistical significance was set at p < 0.00625.

Results

We found a significant causal association that elevated zinc heightens the risk of developing osteomyelitis in European ancestry individuals OR = 1.23 [95% confidence interval (CI) [1.07, 1.43]; p = 4.26E-03]. Similarly, vitamin B6 showed a similar significant causal effect on osteomyelitis as a risk factor OR = 2.78 (95% CI [1.34, 5.76]; p = 6.04E-03; in the secondary analysis). Post-hoc analysis suggested this result (vitamin B6). However, the multivariable Mendelian randomization (MVMR) provides evidence against the causal association between zinc and osteomyelitis OR = 0.98(95% CI [-0.11, 0.07]; p = 7.20E-1). After searching in PhenoScanner, no SNP with confounding factors was found in the analysis of vitamin B6. There was no evidence of a reverse causal impact of osteomyelitis on zinc and vitamin B6.

Conclusion

This study supported a strong causal association between vitamin B6 and osteomyelitis while reporting a dubious causal association between zinc and osteomyelitis.

Organisms Causing Postoperative Implant Infection in Orthopedic Patients Presenting at a Tertiary Care Hospital

Introduction Infections pose a significant challenge in orthopedics related to implant failure. In orthopedic surgeries, surgical site infections (SSIs) extend the patient's hospital stay by an average of two weeks and also increase morbidity, double hospitalization rates, and triple the financial burden on the patient. This study aims to determine the common organism in patients with postoperative implant infections presenting at a tertiary care hospital. Methods A cross-sectional study was conducted in the Department of Orthopedic Surgery at JPMC Karachi over a six-month period, from November 24, 2022, to May 25, 2023. All patients of both genders aged 18-65 years presenting with postoperative implant infection within six hours of the development of symptoms were enrolled. Baseline demographic details and clinical histories were recorded at the time of presentation. A swab for culture and sensitivity was taken from the implant site using a sterile swab stick in patients with confirmed or suspected infections. Results Of 196 patients, the mean age of the patients was 48.47±5.19 years. Gender distribution showed that 49% of patients were females and 51% were males. The mean duration of surgery was 1.71±0.49 hours (100 minutes approximately); Klebsiella species 26% and Staphylococcus aureus 25.5% were the most common organisms isolated from infected surgical wounds, followed by Pseudomonas species in 32 patients (16.3%), Acinetobacter species in 27 patients (13.8%), Escherichia Coli in 23 patients (11.7%), and coagulase-negative Staphylococcus in 13 patients (6.6%). Conclusion In our cohort, Staphylococcus species and Klebsiella species were the most common pathogens isolated from postoperative implant infections. The rise in Klebsiella species suggests that changes in prophylactic antibiotic practices may have contributed to this trend. Therefore, there is an urgent need to reassess current prophylactic strategies in light of the increasing incidence of infections caused by gram-negative bacteria.

Recent Advances in Antibacterial Coatings to Combat Orthopedic Implant-Associated Infections

Implant-associated infections (IAIs) represent a major health burden due to the complex structural features of biofilms and their inherent tolerance to antimicrobial agents and the immune system. Thus, the viable options to eradicate biofilms embedded on medical implants are surgical operations and long-term and repeated antibiotic courses. Recent years have witnessed a growing interest in the development of robust and reliable strategies for prevention and treatment of IAIs. In particular, it seems promising to develop materials with anti-biofouling and antibacterial properties for combating IAIs on implants. In this contribution, we exclusively focus on recent advances in the development of modified and functionalized implant surfaces for inhibiting bacterial attachment and eventually biofilm formation on orthopedic implants. Further, we highlight recent progress in the development of antibacterial coatings (including self-assembled nanocoatings) for preventing biofilm formation on orthopedic implants. Among the recently introduced approaches for development of efficient and durable antibacterial coatings, we focus on the use of safe and biocompatible materials with excellent antibacterial activities for local delivery of combinatorial antimicrobial agents for preventing and treating IAIs and overcoming antimicrobial resistance.