A Prospective, Tripled-Blinded, Randomized Controlled Trial Evaluating Vitamin D3 Supplementation on Post-Operative Functional and Clinical Outcomes Following Total Knee Arthroplasty

Patients will be enrolled from the clinics of Dr. Denis Nam and Dr. Craig Della Valle, two fellowship-trained orthopedic surgeons in the division of Adult Reconstruction at Midwest Orthopedics at Rush University Medical Center. Study staff will screen the clinic schedule of each surgeon and will discuss the purposes of the investigation at the time of their visit. If the patient is willing to participate in the investigation, verbal and written consent will be obtained by the study staff. At the time of consenting, patients will also be asked to perform a TUG test and will be asked to complete the questions that comprise the functional component of the KSS score.

This study will be tripled-blinded, thus, the patients, clinicians, and research staff involved will be unaware of patient allocation during this study. Each patient will receive a study ID, and a computer randomization system will be used to allocate patients to receive either vitamin D3 or placebo based on their study ID. Only members of the Rush pharmacy staff will possess the list matching the study ID to the study group assignment, ensuring that the study remains triple-blinded and that study coordinators are unaware of a patient's assignment when he or she picks up the study medication from the pharmacy.

Patients randomized to the experimental arm of the study will receive 50,000IU of vitamin D3 following surgery and asked to take the medication orally following surgery. Vitamin D3 was selected over vitamin D2 as the former is less expensive and is more effective at raising serum 25-OH vitamin D levels than the latter. The regimen of 50,000IU given once was selected as this regimen has been previously used without side effects in previous studies and has been shown to be as effective as other regimens that utilize more frequent dosing with smaller doses. Patients randomized to the control arm will receive placebo tablets and advised to consume their medication similar to the treatment arm. Both groups of patients will receive their medications from the pharmacy at Rush Medical Center, which will be responsible for providing patients with the appropriate regimen. All patients will receive the same postoperative multimodal analgesic regimen that is normally administered to patients undergoing THA and TKA at Rush University Medical Center.

In accordance with current standard post-operative care, patients will be asked to follow-up with their surgeon in clinic at 3 weeks and 6 weeks following surgery. At these post-operative visits, patients will be asked to repeat the TUG test and the 17-questions of the functional component of the KSS score.