The effect of vitamin D supplementation on outcomes following total hip or knee arthroplasty surgery: a rapid systematic review of current evidence.

Purpose: Vitamin D deficiency has been linked to poorer outcomes following hip (THR) and knee (TKR) replacement. We review the effect of peri-operative supplementation on clinical and patient-reported outcomes following THR/TKR. Methods: This study was registered with PROSPERO (CRD42021238086). Searches of electronic databases were performed from inception to March 2021. All randomised, cohort, or case-controlled studies reported in English of adults undergoing THR/TKR where vitamin D supplementation was given peri-operatively and at least one outcome was reported were included. Studies reporting on vitamin D in relation to osteoporosis and hip fracture were excluded, as were conference abstracts and those involving preclinical models. Risks of bias were performed using the RoB-2 and ROBINS-I tools. Results: Three studies comprising 413 TKR patients were identified; two were randomised controlled trials and one was a prospective cohort study. No studies meeting the inclusion criteria reported on the outcomes following THR. Supplementation was associated with a statistically significant reduction in the IL6:IL10 ratio at 24- and 48h following surgery, but no effect was noted on Western Ontario and McMaster Universities Osteoarthritis Index scores or the rates of falls. All studies were judged to be limited by bias, with heterogeneity in the supplementation dose and timing of administration, as well as the reported outcome measures used. Discussion: Further adequately powered randomised-controlled trials using vitamin D supplementation and a specific clinically relevant or patient-reported outcome measure are required to assess if pre-operative vitamin D insufficiency is a modifiable risk factor to improve outcomes following THR/TKR.