BackgroundLow vitamin D levels affects muscle function. Vitamin D and calcium deficiency cause osteomalacic myopathy and poor functional recovery after hip fractures. The relationship of vitamin D and functional performance after total knee arthroplasty (TKA) is not previously reported.MethodsInfluence of vitamin D on functional performance before and after TKA was reviewed retrospectively in 120 patients. Of these, 64 had vitamin D deficiency (25-hydroxy vitamin D < 30 ng/mL) preoperatively. All 120 patients received vitamin D oral supplementation postoperatively. Functional parameters including Western Ontario and McMaster Osteoarthritis Index (WOMAC), Short-Form Health Survey questionnaire, and Knee Society Score were assessed pre- and postoperatively at 3 months.ResultsPreoperative function was significantly lower in osteoarthritic patients with vitamin D deficiency (WOMAC score; p = 0.040), but at 3 months all functional scores were similar.ConclusionsWe concluded that vitamin D deficiency has a negative effect on function in knee osteoarthritic patients. However, postoperative vitamin D supplementation can lead to functional recovery in these patients. Thus, TKA should not be delayed in vitamin D deficient patients; rather supplementation in the postoperative period is preferable to achieve comparable functional outcome at 3 months to patients with vitamin D sufficiency.

Background Some patients with early periprosthetic joint infection (PJI) can be treated successfully using open débridement with polyethylene exchange rather than twostage revision; however, the challenge is to diagnose PJI early. In late infection, C-reactive protein (CRP) and interleukin-6 (IL-6) are elevated, but shortly after surgery, CRP is difficult to interpret because it may be elevated even in the absence of infection, and we know little about the normal trajectory of IL-6 immediately after arthroplasty. If a deviation of biomarkers from their normal trajectory is seen, it may help guide the clinician toward early knee aspiration. Questions/purposes We studied the normal trajectories of IL-6 and CRP in the immediate hours and days after uncomplicated TKA and examined whether one or the other normalizes more quickly. Methods We studied serum IL-6 and CRP levels in 50 patients undergoing primary TKA at five time points: 12 hours preoperatively and postoperatively at 12 hours, 48 hours, 4 days, and 2 weeks. One surgeon operated on all Each author certifies that neither he, nor any member of his immediate family, has funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. Clinical Orthopaedics and Related Research® neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDA approval status, of any drug or device before clinical use. Each author certifies that his institution approved the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research.