Vitamin D Deficiency Is Associated With Longer Hospital Stay And Lower Functional outcome After Total Knee Arthroplasty.

High vitamin D deficiency prevalence has been found in hip and knee osteoarthritis, and a correlation between low vitamin D levels and worse functional outcome after hip arthroplasty was published before. Our goal was to examine the relation between vitamin D levels and outcome after knee arthroplasty on short and long term. In 138 patients with knee replacements preoperative vitamin D levels were recorded. 33 patients were vitamin D deficient (median 32 nmol/l, range 6-40 nmol/l) and 105 patients were vitamin D sufficient (median 65 nmol/l, range 41-177 nmol/l). After correction for confounders, vitamin D deficient patients had significant (p = 0.03) longer hospital stay (+1.0 day, range 0.2-1.6 day), and significant (p = 0.04) worse functional outcome also at long term follow up after eight years (WOMAC : +5.0, range 0.2-9.8). More research is needed to evaluate if rehabilitation and postoperative outcome can be improved by preoperative vitamin D suppletion.