The colonisation of the glenohumeral joint by Propionibacterium acnes is not associated with frozen shoulder but is more likely to occur after an injection into the joint

AimsOur aim was to investigate the prevalence of Propionibacterium (P.) acnes in the subcutaneous fat and capsule of patients undergoing shoulder surgery for frozen shoulder or instability.Patients and MethodsA total of 46 patients undergoing either an arthroscopic capsular release or stabilisation had biopsies taken from the subcutaneous fat and capsule of the shoulder at the time of surgery. These samples were sent for culture in enrichment, and also for Nucleic Acid Amplification testing. The prevalence of P. acnes and other microbes was recorded. Fisher's exact test of binary variables was used to calculate the association with significance set at p < 0.05. Assessment of influence of independent variables including a pre-operative glenohumeral injection, fat colonisation and gender, was undertaken using binary linear regression.ResultsA total of 25 patients (53%) had P. acnes in one or more tissue samples and 35 (74%) had other bacterial species. The same microbe was found in the subcutaneous fat and ...