Timing Is Everything: Commentary on an article by Brian Forsythe, MD, et al.: "The Timing of Injections Prior to Arthroscopic Rotator Cuff Repair Impacts the Risk of Surgical Site Infection"

Smoking increases the risk of infectious diseases: A narrative review

Smoking is relevant to infectious diseases resulting in increased prevalence and mortality. In this article, we aim to provide an overview of the effects of smoking in various infections and to explain the potential mechanisms. We searched PubMed and other relevant databases for scientific studies that explored the relationship between smoking and infection. The mechanisms of susceptibility to infection in smokers may include alteration of the structural, functional and immunologic host defences. Smoking is one of the main risk factors for infections in the respiratory tract, digestive tract, reproductive tract, and other systems in humans, increasing the prevalence of HIV, tuberculosis, SARS-CoV, and the current SARS-CoV-2. Smoking cessation can reduce the risk of infection. Smoking increases the incidence of infections and aggravates the progress and prognosis of infectious diseases in a dose-dependent manner. Smoking cessation promotion and education are the most practical and economical preventive measures to reduce aggravation of disease infection owing to tobacco use.

Adverse Impact of Corticosteroid Injection on Rotator Cuff Tendon Health and Repair: A Systematic Review

PURPOSE

To assess adverse effects of preoperative corticosteroid injections (CSIs) in patients with rotator cuff disease, especially before rotator cuff repair (RCR).

METHODS

A systematic review of the MEDLINE database was performed according to guidelines from the Preferred Reporting Item for Systematic Reviews and Meta-Analyses for all studies reporting on adverse clinical effects of CSIs on rotator cuff tendon.

RESULTS

A total of 8 articles were identified that report on adverse outcomes and risks associated with corticosteroid injections in the setting of rotator cuff tendinosis. Among these included articles, a single CSI for rotator cuff tendinosis was associated with increased risk of revision rotator cuff repair (odds ratio [OR]: range 1.3 [1.1-1.7] to 2.8 [2.2-3.4]) when administered up to a year before surgery and postoperative infections (OR: 2.1 [1.5-2.7]) when administered within a month before RCR. The risk of adverse outcomes after rotator cuff repair are greatest if a CSI is administered within 6 months of surgery (OR: 1.8 [1.3-2.6]) or if ≥2 injections are given within a year of surgery (OR: range 2.1 [1.8-2.5] to 3.3 [2.7-4.0]).

CONCLUSION

Several recent clinical trials have demonstrated that CSIs are correlated with increased risk of revision surgery after RCR in a temporal and dose dependent matter. Caution should be taken when deciding to inject a patient, and this treatment should be withheld if an RCR is to be performed within the following 6 months.

LEVEL OF EVIDENCE

IV, systematic review of Level III and IV studies.

Adverse Impact of Corticosteroids on Rotator Cuff Tendon Health and Repair: A Systematic Review of Basic Science Studies

Purpose

To evaluate the in vitro effects of corticosteroid injections (CSIs) on rotator cuff tendon (RCT).

Methods

A systematic review of the MEDLINE database was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for all studies reporting on adverse biochemical and biomechanical effects of CSIs on RCT.

Results

Sixteen studies were identified that had been published in the last 15 years on the effects of corticosteroids on RCTs. Eight of these studies were on human RCTs, 6 were on rat tendons, 1 considered both human and rat tendons, and 1 was on dog tendon. Five studies analyzed the effects of corticosteroids on the biomechanical properties of RCT or rotator cuff repair, whereas the remaining observed the cellular and molecular effects of CSIs on RCT. Corticosteroids suppress an inflammatory response, induce apoptosis, and have negative effects on collagen and tendon cell viability in RCTs. The mechanical properties, including load to failure of RCTs and rotator cuff repair anchor pull-out strength, also are decreased by CSIs. These in vitro effects appear to be transient as well as frequency and dose dependent.

Conclusions

On a molecular level, CSIs decrease cellular proliferation, alter collagen and extracellular matrix composition, impede inflammatory pathways, decrease cellular viability, increase adipocyte differentiation, and increase apoptosis. These changes can be seen as early as 24 hours after corticosteroid exposure, last as long as 2 to 3 weeks, and are exacerbated by increased doses and decreased latency between doses. Biomechanical studies demonstrate that these changes result in decreased maximal load to failure, tendon stiffness, and suture anchor pull-out strength in rat shoulders up to 2 weeks but not at 3 and 4 weeks, post-CSI.

Clinical Relevance

Shoulder subacromial steroid injection is common, and practitioners should be aware of results both positive and deleterious.