Can Topical Vancomycin Prevent Periprosthetic Joint Infection in Hip and Knee Arthroplasty? A Systematic Review.

BACKGROUND: Periprosthetic joint infection (PJI) after hip and knee arthroplasty is a leading cause of revision surgery, inferior function, complications, and death. The administration of topical, intrawound vancomycin (vancomycin powder) has appeared promising in some studies, but others have found it ineffective in reducing infection risk; for that reason, a high-quality systematic review of the best-available evidence is needed. QUESTIONS/PURPOSES: In this systematic review, we asked: (1) Does topical vancomycin (vancomycin powder) reduce PJI risk in hip and knee arthroplasty? (2) Does topical vancomycin lead to an increased risk of complications after hip and knee arthroplasty? METHODS: A search of Embase, MEDLINE, and PubMed databases as of June 2020 was performed according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Studies comparing topical vancomycin in addition to standard infection prevention regimens (such as routine perioperative intravenous antibiotics) with standard regimens only in primary hip and knee arthroplasty were identified. Patients 18 years or older with a minimum follow-up of 3 months were included. No restrictions on maximal loss to follow-up or PJI definition were imposed. Studies were excluded if they included patients with a history of septic arthritis, used an antibiotic other than vancomycin or a different route of administration for the intervention, performed additional interventions that differed between groups, or omitted a control group. A total of 2408 studies were screened, resulting in nine eligible studies reviewing 3371 patients who received topical vancomycin (vancomycin powder) during a primary THA or TKA and 2884 patients who did not receive it. Groups were comparable with respect to duration of follow-up and loss to follow-up when reported. Study quality was assessed using the Newcastle-Ottawa scale, showing moderate-to-high quality for the included studies. The risks of PJI and overall complications in the topical vancomycin group were compared with those in the control group. RESULTS: One of nine studies found a lower risk of PJI after primary THA or TKA, while eight did not, with odds ratios that broadly bracketed the line of no difference (range of odds ratios across the nine studies 0.09 to 1.97). In the six studies where overall complications could be compared between topical vancomycin and control groups in primary THA or TKA, there was no difference in overall complication risks with vancomycin (range of ORs across the six studies 0.48 to 0.94); however, we caution that these studies were underpowered to detect differences in the types of uncommon complications associated with vancomycin use (such as allergy, ototoxicity, and nephrotoxicity). CONCLUSION: In the absence of clear evidence of efficacy, and without a sufficiently large evidence base reporting on safety-related endpoints, topical vancomycin (vancomycin powder) should not be used in routine primary THA and TKA. Adequately powered, multicenter, prospective trials demonstrating clear reductions in infection risk and large registry-driven audits of safety-related endpoints are required before the widespread use of topical vancomycin can be recommended. LEVEL OF EVIDENCE: Level III, therapeutic study.

Ionotropic receptors and ion channels in ischemic neuronal death and dysfunction.

Loss of energy supply to neurons during stroke induces a rapid loss of membrane potential that is called the anoxic depolarization. Anoxic depolarizations result in tremendous physiological stress on the neurons because of the dysregulation of ionic fluxes and the loss of ATP to drive ion pumps that maintain electrochemical gradients. In this review, we present an overview of some of the ionotropic receptors and ion channels that are thought to contribute to the anoxic depolarization of neurons and subsequently, to cell death. The ionotropic receptors for glutamate and ATP that function as ligand-gated cation channels are critical in the death and dysfunction of neurons. Interestingly, two of these receptors (P2X7 and NMDAR) have been shown to couple to the pannexin-1 (Panx1) ion channel. We also discuss the important roles of transient receptor potential (TRP) channels and acid-sensing ion channels (ASICs) in responses to ischemia. The central challenge that emerges from our current understanding of the anoxic depolarization is the need to elucidate the mechanistic and temporal interrelations of these ion channels to fully appreciate their impact on neurons during stroke.

Classical electrical and hydraulic Windkessel models validate physiological calculations of Windkessel (reservoir) pressure.

Our "reservoir-wave approach" to arterial hemodynamics holds that measured arterial pressure should be considered to be the sum of a volume-related pressure (i.e., reservoir pressure, P(reservoir)) and a wave-related pressure (P(excess)). Because some have questioned whether P(reservoir) (and, by extension, P(excess)) is a real component of measured physiological pressure, it was important to demonstrate that P(reservoir) is implicit in Westerhof's classical electrical and hydraulic models of the 3-element Windkessel. To test the validity of our P(reservoir) determinations, we studied a freeware simulation of the electrical model and a benchtop recreation of the hydraulic model, respectively, measuring the voltage and the pressure distal to the proximal resistance. These measurements were then compared with P(reservoir), as calculated from physiological data. Thus, the first objective of this study was to demonstrate that respective voltage and pressure changes could be measured that were similar to calculated physiological values of P(reservoir). The second objective was to confirm previous predictions with respect to the specific effects of systematically altering proximal resistance, distal resistance, and capacitance. The results of this study validate P(reservoir) and, thus, the reservoir-wave approach.

Outcomes following pelvic ring fractures in the paediatric population: A systematic review.

BACKGROUND: Pelvic fractures represent a small proportion of all paediatric fractures, but are likely to be associated with a high-energy mechanism, multiple injuries, and significant morbidity and mortality. Operative fixation of unstable pelvic fractures is accepted. However, there remains a paucity of data on functional outcomes and complications following pelvic fractures in the skeletally immature. METHODS: A PRISMA-compliant systematic review was performed, searching Medline, Embase, and Cochrane central review. The primary outcome was functional outcome after pelvic fractures in the paediatric population following operative or non-operative treatment. Secondary outcomes included mechanism of injury, associated injuries, mortality rate, and method of surgical fixation if required. Where possible, weighted totals of the data set were performed. RESULTS: In total, 23 studies were included in this review. Only eight studies reported functional outcomes, with limb length discrepancy and limp being the most common complication. Only 8.8% of all pelvic fractures underwent surgical fixation. Motor vehicle collision was the most common cause of injury, and extremity fracture was the most common associated injury. CONCLUSION: Paediatric pelvic fractures are caused by high-energy mechanisms and have significant morbidity and mortality. There remains a paucity of information on functional outcomes after these injuries.

Diagnosis and Management of Deltoid Ligament Insufficiency.

BACKGROUND: Surgical management of patients with acute and chronic ankle instability (CAI) has historically focused on the lateral ligament complex. Recent studies in CAI patients have shown that magnetic resonance imaging (MRI) and arthroscopy demonstrate concomitant injury to the deltoid ligament complex We performed a systematic review to determine if consistent clinical, diagnostic imaging, or arthroscopic findings of deltoid ligament injury in the setting of CAI have been described. In addition, we sought to determine if treatment options and/or clinical outcomes have been described. METHODS: A systematic review was conducted using the PubMed, MEDLINE, and Embase databases. Articles were included if they had a majority of patients 18 years of age or older, focused on deltoid ligament injury in ankle instability, and reported diagnostic and/or treatment methods. Articles were excluded if the study focused on the deltoid ligament in the acute fracture setting. All included articles were assessed for diagnostic criteria, treatments, and patient outcomes. RESULTS: Our search yielded 157 articles, of which a total of 13 were included in our study. Arthroscopy was described as the gold standard to diagnose and evaluate the severity of deltoid ligament injury, however, little objective data on the arthroscopic diagnosis of deltoid ligament insufficiency was reported. MRI was the imaging modality of choice to evaluate deltoid ligament injury and had a high sensitivity and specificity when compared with arthroscopy. No standard MRI diagnostic criteria for deltoid ligament injury were identified in the literature. Specific treatment techniques and long-term outcomes were not well described in the manuscripts included in this review. CONCLUSION: There is limited knowledge on deltoid ligament insufficiency in the setting of chronic ankle instability. Criteria for characterizing deltoid ligament damage with diagnostic imaging appear to be evolving, but there is no standard classification. Only 1 author has described a method to evaluate deltoid ligament competency on arthroscopic examination. There are currently no objective data to guide treatment decisions. LEVEL OF EVIDENCE: Level III.