Intra-Articular Injection and Infection Risk after Shoulder Surgery

Data being presented today indicate that patients who receive an intra-articular injection within the 3 months prior to undergoing elective shoulder arthroscopy or shoulder arthroplasty are at an increased risk of postoperative infection.

“This topic was interesting to my colleagues and I as shoulder surgeons, because patients often request injections to temporarily relieve pain prior to having surgery,” said Brian C. Werner, MD, presenting author. “While many surgeons often recommend a delay between injection and surgery, no convincing data exist that establish a relationship between preoperative injection and postoperative infection, nor how long the interval between injection and surgery should be.”

Conducting the study
The investigators queried a national insurance database for patients who underwent shoulder arthroscopy or shoulder arthroplasty following ipsilateral shoulder injection between 2005 and 2012. Control cohorts were created for each study group by matching patients who underwent the same procedure without a preoperative injection to the study cohorts based on age, gender, obesity, diabetes, and smoking. Three shoulder arthroscopy cohorts were created:

  • arthroscopy within 3 months of ipsilateral shoulder injection (n = 3,625)
  • arthroscopy between 3 and 12 months after ipsilateral shoulder injection (n = 7,069)
  • matched control arthroscopy without prior injection (n = 186,678)

In addition, three shoulder arthroplasty cohorts were created:

  • arthroplasty within 3 months of ipsilateral shoulder injection (n = 636)
  • arthroplasty between 3 and 12 months after ipsilateral shoulder injection (n = 1,573)
  • matched control arthroplasty without prior injection (n = 6,211)

Infection rates within 3 and 6 months postoperatively were assessed using International Classification of Diseases, Ninth Edition (ICD-9) and Current Procedural Terminology (CPT) codes.

Evaluating results

The incidence of infection after shoulder arthroscopy at 3 months (0.7 percent, odds ratio (OR) 2.2, P < 0.0001)="" and="" 6="" months="" (1.1="" percent,="" or="" 1.6,="" />P = 0.003) was significantly higher in patients who underwent injection within the 3 months prior to arthroscopy compared to matched controls. The incidence of infection after shoulder arthroplasty at 3 months (3.0 percent, OR 2.0, P = 0.007) and 6 months (4.6 percent, OR 2.0, P = 0.001) was significantly higher in patients who underwent injection within the 3 months prior to arthroplasty compared to matched controls. There was no significant difference in infection rates in patients who underwent shoulder arthroscopy or arthroplasty between 3 and 12 months after injection compared to controls.

The authors assert that, although these data demonstrate a significant increase in postoperative infection in patients who underwent ipsilateral intra-articular shoulder injection within 3 months prior to shoulder arthroscopy and arthroplasty, this association was not noted when shoulder arthroscopy or arthroplasty occurred more than 3 months after shoulder injection.

“The message of this study is intended to be very straightforward and simple: Injection within 3 months prior to shoulder arthroscopy or shoulder arthroplasty is associated with increased rates of postoperative infection in Medicare patients,” summarized Dr. Werner.

Dr. Werner’s coauthors of Paper 536, “The Timing of Elective Shoulder Surgery after Intra-Articular Injection Affects Postoperative Infection Risk” are Jourdan M. Cancienne, MD; Justin W. Griffin, MD; Matthew T. Burrus, MD; F.W. Gwathmey, MD; and senior author Stephen F. Brockmeier, MD.

Details of the authors’ disclosures as submitted to the Orthopaedic Disclosure Program can be found in the Final Program; the most current disclosure information may be accessed electronically at www.aaos.org/disclosure

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