The Incidence and Incubation Period of False Positive Cultures in Shoulder Surgery

Background Postoperative shoulder infection (PSI) is a significant complication requiring timely identification and treatment. Indolent infections such as those involving Cutibacterium acnes (C. acnes, recently reclassified from Propionibacterium acnes 1) provide a diagnostic dilemma as they present differently without the acute symptoms associated with most postoperative bone and joint infections. Furthermore, C. acnes is thought to be a common contaminant isolated from intraoperative cultures. With no consensus algorithm, long hold cultures play a major role in guiding management decisions in potential PSI. Our study seeks to determine the incidence of positive cultures in both open and arthroscopic procedures in non-infected patients as well as clarify whether or not an increase in the incubation time frame leads to an increased rate of culture growth. Method ology: One hundred patients were prospectively enrolled into either an open and arthroscopic procedure group. Patients with abnormal inflammatory labs, history of previous shoulder surgery, or corticosteroid injection within six months of surgery were excluded from the study. Three cultures were obtained for each patient (1superficial tissue culture, 2- tissue culture, and 3- “sterile” control swab). Cultures were held for 28 days and checked on regular intervals. All patients were followed clinically for 6 months to ensure no signs of postoperative infection. Results Ultimately ninety-five patients were included in the final analysis. The false-positive rate in open shoulder surgery was 17.02% and arthroscopic shoulder surgery was 10.4%. The incidence of positive C. acnes cultures was 6.4% in the open group while C. acnes was not isolated in the arthroscopic group. All positive bacterial cultures were reported within seven days of collection. One culture was positive for “mold” at 26 days. Conclusion A relatively high false-positive culture rate occurred in both open and arthroscopic shoulder surgery. C. acnes was the most commonly identified bacteria in cultures in the open surgery group. Knowledge of one’s own institutional false-positive culture rate could be important in avoiding potentially inappropriate treatment. Additionally, we found that holding cultures longer than 14 days did not lead to an increased rate of false positive culture results

Rehabilitation of older patients: day hospital compared with rehabilitation at home. Clinical outcomes.

OBJECTIVES: to test the hypothesis that older people and their informal carers are not disadvantaged by home-based rehabilitation (HBR) relative to day hospital rehabilitation (DHR). DESIGN: pragmatic randomised controlled trial. SETTING: four geriatric day hospitals and four home rehabilitation teams in England. PARTICIPANTS: eighty-nine patients referred for multidisciplinary rehabilitation. The target sample size was 460. INTERVENTION: multidisciplinary rehabilitation either in the home or in the day hospital. MEASUREMENTS: the primary outcome measure was the Nottingham extended activities of daily living scale (NEADL). Secondary outcome measures included EQ-5D, hospital anxiety and depression scale, therapy outcome measures, hospital admissions and the General Health Questionnaire for carers. RESULTS: at the primary end point of 6 months NEADL scores were not significantly in favour of HBR cf. DHR; mean difference -2.139 (95% confidence interval -6.87 to 2.59, P = 0.37). A post hoc analysis suggested non-inferiority for HBR for NEADL but there was considerable statistical uncertainty. CONCLUSION: taken together the statistical analyses and lack of power of the trial outcomes do not provide sufficient evidence to conclude that patients in receipt of HBR are disadvantaged compared with those receiving DHR