IO Vancomycin in TSA

This study is a prospective, randomized, single-blinded, controlled trial. 20 patients in each treatment arm: 20 patients will be given IV vancomycin, 20 patients will be given IO vancomycin. This sample size is based on previous studies examining vancomycin concentration in tourniquetless primary total knee arthroplasty between IO vs IV [12,13].

Once the participant has been enrolled, they will be randomized into either the control group or the experimental group by an excel-based software program prior to their procedure.

Control - Standard IV administration of vancomycin

• Patients will receive the Houston Methodist Hospital orthopedic surgeon's standard of care pre-operative antibiotic regimen for primary total shoulder arthroplasty patients. This includes IV abx (typically ancef or cefepime and vancomycin) will be started in the pre-operative period approximately 1 hour prior to incision (vancomycin dose weight-based at approximately 15mg/kg [6,7] generally 1000-1750mg in 500mL NS).

Intervention - Intraosseous (IO) administration of vancomycin

• IV antibiotics (per physician's standard of care): Typically ancef or cefepime is started in pre-op within 1 hour of incision
• IO vancomycin is administered in the OR after sterile prep and draping has occurred (500mg in 100-150mL NS).
• Injection will take place into the proximal humerus

All patients in both groups will be monitored during the surgery and immediately post-operatively for adverse injection reactions (i.e. Red Man Syndrome) as this is the standard of care.

All patients (IV and IO) will otherwise follow identical post-operative protocols (including post-operative antibiotic administration)

Intra-Op Sample Collection

Samples will be taken from the following locations at the following times:

Systemic Sample - Start of Case A vancomycin blood level will be drawn by the anesthesiologist staff (CRNA, MD) at the start of incision and should occur simultaneously with the final soft tissue sample collection below Soft tissue sample - Synovium Start A small soft tissue sample will be taken from the synovium upon entering the shoulder joint. This sample will only be taken if it is readily available for the surgeon to gather.

Bone Sample - Bone from Humeral Head After the humeral neck is cut with the "cookie cutter" instrument a portion of humeral head/neck will be removed and placed in a separate specimen jar (remainder of head will be sent to pathology as usual).

Soft Tissue Sample - Synovium End A small soft tissue sample will be taken from the synovium prior to initiation of wound closure. This sample will only be taken if it is readily available for the surgeon to gather.

Systemic Sample A vancomycin blood level will be drawn by the anesthesiologist staff (CRNA, MD) at the time of initiation of closure and should occur simultaneously with the final soft tissue sample collection above

Data Variables to be Recorded Age (calculated from DOB), date of surgery, discharge date, sex, laterality, study group, pre-op creatinine, post-op creatinine, systemic vancomycin level at incision, soft tissue vancomycin level (synovium start and synovium end), humeral head bone sample vancomycin level, and systemic vancomycin level at initiation of wound closure. Additionally, adverse local/systemic reactions as determined from patient's chart, 30-day complications, 90-day complications, cost, time from antibiotic administration to incision, operative time, and incision time.

Inclusion criteria

• Patient is undergoing anatomic or reverse shoulder arthroplasty
• Patient is able to give informed consent to participate on the study. LAR consents will not be utilized for this study
• Age Range >18

Exclusion criteria

• Previous shoulder surgery
• BMI above 35
• Contraindication to receiving vancomycin, cefepime, ancef, or other standard of care pre-operative antibiotic (allergy, medical issue, etc).
• Inability to administer the IO infusion
• Refusal to participate
• Diabetes
• Immunocompromised or immunosuppressed patients (HIV, Hep C, ESRD, dialysis, transplant, chemo/radiation treatment in last 6 months, medications)