Study investigators propose to investigate if a bony injection of pain medication during a knee replacement will help pain levels following primary knee replacement surgery. To investigate this, 86 patients will be enrolled. Half of the patients will receive a bony injection of antibiotics with morphine (pain medication) while the other half will receive a bony injection of antibiotics with placebo (no pain medication). Following surgery, patient pain levels and pain medication consumption will be measured.

The injection is intraosseous meaning in the bone. The needle pierces the bone and the medication is injected into the bone. The site of injection is on the anterior (front) of the upper portion of the tibia. The medications are Vancomycin (antibiotic) and Morphine (pain medication) which are mixed in separate syringes and then injected. Intraosseous vancomycin is standard of care while intraosseous vancomycin with morphine is also standard of care, depending on operating surgeon.

Inclusion Criteria:

1. 18-100 years old
2. Primary total knee arthroplasty
3. Participants must be able to consent for themselves
4. Capable and comfortable with text messaging

Exclusion Criteria:

1. Non-primary total knee arthroplasty
2. Intraoperative or postoperative deviation from standard of care
3. Post-traumatic surgical indication
4. Post-infectious surgical indication
5. Chronic narcotic use or history of narcotic addiction
6. Allergy to vancomycin
7. Allergy to morphine
8. Inability to receive spinal anesthesia
9. Inability to receive intraoperative adductor canal block
10. Inability to provide informed consent for the study
11. Inability to speak English fluently

Patients, care team, and research team are all blinded to their respective group until the study is concluded.