Outcome of total hip and total knee arthroplasty and vitamin D homeostasis.

BACKGROUND: Low levels of vitamin D are common in patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA), but it is still unclear whether the outcome of such surgery is related to vitamin D levels. SOURCES OF DATA: Publicly available electronic databases were systematically reviewed to update knowledge about the role of vitamin D in THA and TKA patients, and to appraise the correlation between vitamin D levels before surgery and post-surgical outcomes. Eight studies were included in our review: six employed prospective observational designs, two reported retrospective database interrogations. Six prospective observational studies and two retrospective database interrogations matched inclusion and exclusion criteria. AREAS OF AGREEMENT: Patients undergoing THA and TKA have a high prevalence of hypovitaminosis D. Five of eight studies (62.5%) report a statistically significant association between low vitamin D status and worse outcomes after THA and TKA. AREAS OF CONTROVERSY: Different explanations have been proposed for vitamin D insufficiency, but some authors have questioned the correctness of the methods used to measure the vitamin D levels. GROWING POINTS: A trial focusing on the role of vitamin D supplementation on safety and outcomes of patients undergoing THA and TKA with low vitamin D status is ongoing. AREAS TIMELY FOR DEVELOPING RESEARCH: Further studies should explore the possible causal relationship between vitamin D status and outcomes of THA and TKA and verify the laboratory methods to analyse it.