Introduction

Surgeons often encounter challenges during redo procedures that are absent in initial operations. Specifically, the risk of shoulder revision surgery infection remains a critical concern for orthopedic specialists. A recent prospective comparative study has highlighted a stark contrast in the incidence of unexpected positive cultures (UPCs) between revision and primary arthroscopic shoulder stabilization surgeries. This finding suggests that subclinical colonization may play a larger role in revision cases than previously documented.

Study Methodology and Participant Cohort

Researchers consecutively enrolled 68 patients between August 2022 and December 2024. The cohort consisted of 34 patients undergoing revision stabilization and 34 undergoing primary stabilization. Notably, all procedures were performed by the same surgeon to ensure consistency. To maintain study integrity, the team excluded patients with any prior clinical signs of infection, recent antibiotic use, or those undergoing open surgery. They collected intraoperative tissue samples before administering prophylactic antibiotics, sending them for rigorous microbiological analysis.

Key Findings: The Prevalence of UPCs

The results demonstrated a significant disparity between the two groups. Revision surgeries exhibited a significantly higher rate of UPCs, at 17.6% (6 patients), while the primary group showed zero positive cultures. Consequently, the statistical analysis confirmed a p-value of .025. In terms of microbiology, Cutibacterium acnes was the dominant organism, identified in 83.3% of the positive cases. In contrast, Staphylococcus aureus appeared in only one instance. Interestingly, the study found no significant differences regarding age, sex, or smoking status between the groups, suggesting that the revision status itself is the primary risk factor.

Clinical Implications for Shoulder Revision Surgery Infection

The high incidence of C. acnes in revision cases underscores the indolent nature of this pathogen. Because these organisms often reside deep within the sebaceous glands, they can evade standard surface debridement. Therefore, clinicians must maintain a high index of suspicion when managing patients who experience persistent pain or stiffness after a secondary stabilization. Furthermore, the absence of UPCs in primary cases suggests that the initial surgical environment is relatively sterile compared to the altered landscape found during revision work.

Conclusion

The incidence of UPCs is significantly higher in revision arthroscopic shoulder stabilization than in primary procedures. Surgeons should consider these findings when planning postoperative care and monitoring for potential low-grade infections. While the clinical significance of every positive culture is still debated, acknowledging the increased microbial burden in revision cases is vital for improving surgical outcomes.

Frequently Asked Questions

What is an unexpected positive culture (UPC)?

A UPC occurs when intraoperative tissue samples grow bacteria despite the patient showing no preoperative clinical or laboratory signs of a surgical site infection.

Why is C. acnes common in shoulder revision surgery infection cases?

C. acnes is a normal inhabitant of the skin and hair follicles around the shoulder. Its indolent nature allows it to colonize deeper tissues and implants without causing acute, obvious symptoms of infection.

Does a positive culture always require antibiotic treatment?

Not necessarily. The decision to treat a UPC depends on the number of positive samples, the specific organism identified, and the patient's clinical symptoms, such as unexplained pain or stiffness.

Disclaimer: This content is for informational and educational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Refer to the latest local and national guidelines for clinical practice.

References

Ameztoy J et al. Significantly Higher Rate of Unexpected Positive Cultures in Revision Surgery Than in Primary Arthroscopic Shoulder Stabilization Surgery. Arthroscopy. 2026 Apr 18. doi: 10.1002/arj.70130. PMID: 42001204.