ABSTRACT
BACKGROUND: The effect of postoperative shoulder sling compliance on surgical outcomes is unknown. The goal was to determine an accurate method to measure sling compliance. We compared volunteer recorded sling wear time with temperature-based sensors to monitor sling compliance. METHODS: Data loggers sutured at three locations measured heat generated in 15-minute intervals. Slings wearers logged sling wear to accurately cross-reference with temperature sensors. Secondary experiments analyzed whether surrounding ambient temperature can be discerned from actual sling wear. We created an algorithm to describe actual sling wear time as a function of heat recorded and calculated percent wear accuracy. RESULTS: The modified sling was worn for 172 h. The algorithm modeled sling on/off times by analyzing cutoff temperatures. Diagnostic accuracy was >99 % for the three locations, with no statistically significant differences among them. Compared with sling wear, ambient temperature took longer to reach critical temperature values determined by the algorithm, helping distinguish compliance from false positives. CONCLUSIONS: The described algorithm can effectively quantify shoulder sling wear time based on heat-generated sensor readings. False positives from ambient temperature are minimal. This measurement method could be used to study the relationship between postoperative sling use and functional outcomes after shoulder surgery.
Subject(s)
Braces , Shoulder , Humans , Monitoring, Physiologic , Postoperative Period , Shoulder/surgery , TemperatureABSTRACT
OBJECTIVE: The impact of rotator cuff (RC) tear pattern on intramuscular fatty infiltration (FI) is not well understood. The purpose of our study is to determine if differing RC tear patterns are associated with discordant presentations of intramuscular FI. METHODS: Fifty-one adults with full-thickness tear of the posterosuperior RC on shoulder magnetic resonance imaging (MRI) were identified retrospectively. The study subjects were stratified by RC tear pattern: (1) L-shaped tear cohort, (2) crescent-/U-shaped tear cohort, and (3) complete tear cohort. Clinical information pertaining to age, sex, tear size, trauma history, and length of clinical symptoms was recorded from the institution's picture archiving and communication system. Goutallier grade was assessed on oblique sagittal T1-weighted MRI by two orthopedic surgeons and one orthopedic resident. A musculoskeletal radiologist recorded the shape and size of full-thickness RC tears. Descriptive, correlation, and reliability analyses were performed. RESULTS: The L-shaped, crescent-/U-shaped, and compete tear cohorts demonstrated significant differences pertaining to tear size (P < 0.001) and infraspinatus Goutallier grade (P = 0.024), but not supraspinatus Goutallier grade (P = 0.370). Age had strong correlation to supraspinatus Goutallier grade (rs = 0.712, P = 0.031) and infraspinatus Goutallier grade (rs = 0.712, P = 0.029) in the crescent-/U-shaped tear cohort. Tear size had strong correlation to supraspinatus Goutallier grade (rs = 0.796, P = 0.001) and infraspinatus Goutallier grade (rs = 0.793, P = 0.001) in the complete tear cohort. Moderate interobserver agreement was present for supraspinatus (kappa, 0.484) and infraspinatus (kappa, 0.427) Goutallier grade. CONCLUSION: RC tear pattern is associated with different presentations of intramuscular FI at the posterosuperior RC. Full-thickness tears involving the crescent region of the RC cuff are associated with age. Intramuscular FI is associated with RC tear size.
ABSTRACT
OBJECTIVES: To evaluate the effectiveness of intraoperative vancomycin powder in prevention of surgical site infection and biofilm formation on implants in a contaminated animal fixation model. METHODS: We created a rabbit surgical model including fixation implants at a tibial surgical site seeded with methicillin-resistant Staphylococcus aureus. Our study cohort included 18 rabbits. Nine received vancomycin powder at the surgical site, and the other 9 did not. Serum vancomycin levels were measured at scheduled time points over 24 hours. Bone infection and implant biofilm formation were determined based on the number of colony-forming units present 2 weeks after surgery. Radiography, histology, and electron microscopy aided in evaluation. RESULTS: No bone infection or implant colonization occurred in the vancomycin powder group. Six bone infections and 6 implant biofilm formations (67%; 95% confidence interval, 45%-88%) occurred in the group that did not receive vancomycin powder (P = 0.009). Serum vancomycin levels were detectable at minimal levels at 1 and 6 hours only. Pathological changes occurred in the specimens that were positive for infection. CONCLUSIONS: Intraoperative vancomycin powder application at the time of fixation decreases risk for bone infection and biofilm formation on implants in a rabbit model, with minimal increase in serum vancomycin levels. The results are encouraging and support the rationale for a clinical trial investigating the use of local vancomycin powder to reduce the rate of surgical site infections. CLINICAL RELEVANCE: Infection is a common complication of surgery, especially with implants. Simple methods to prevent or decrease the occurrence of infection would benefit the patient and the health care system.
