Exploration of Serum 25-Hydroxy Vitamin D in Total Joint Arthroplasty within a Subtropical Climate

Background: The importance of appropriate serum 25-hydroxy vitamin D [25(OH)D] for multiple health measures is widely described, however, the prevalence of vitamin D deficiency remains remarkably high. The goal of our study is to explore the distribution of vitamin D deficiency among an elective total joint arthroplasty (TJA) population within a lower latitude climate with relatively abundant sunshine. We hypothesize this group will demonstrate a high prevalence of vitamin D deficiency, thus exposing a potential opportunity to improve outcomes with proper management. Methods: From January to December, 2014, serum 25(OH)D levels were collected during a standard preoperative workup prior to primary or revision joint arthroplasty in South Carolina. Mean serum 25(OH)D, seasonal variation, and patient demographics were recorded. We defined Vitamin D deficiency consistent with the current Endocrine Society classification: serum 25(OH)D < 20 ng/ml, 21-29 ng/ml, and 30-100 ng/ml representing deficiency, insufficiency, and normal, respectively. Results: A total of 308 patients underwent evaluation. 46.8% (144) of the participants were female, and 89.6% (276) identified as Caucasian. The mean patient age was 68.3 years + 13.8 (32-88). The average serum 25(OH)D was 29.8 ng/ml + 12.8 (5.1-79.9), with only 46.2% of patients having a normal serum 25(OH)D (p=0.0001). Caucasian and non-white patients averaged 33 ng/ml [56% normal 25(OH)D] and 25 ng/ml [36% normal 25(OH)D], respectively (p = 0.22). Patients over the age of 65 demonstrated lower serum 25(OH)D (28.5ng/ml) compared to those under 65 (30.7ng/ml)(p=.12). As expected, serum 25(OH)D demonstrated variation throughout the year: January to March, April to June, July to September, and October to December recorded 28.5 ng/ml, 31.73 ng/ml, 36.57 ng/ml, and 23.03 ng/ml 25(OH)D, respectively. Conclusion: The majority (53.8%) of an otherwise classically low risk patient population present with vitamin D insufficiency or deficiency prior to undergoing elective total joint arthroplasty, with elderly non-white patients in the winter months at the highest risk. Appropriate vitamin D management is associated with favorable influences on both skeletal and non-skeletal outcomes. Potential complications of total joint arthroplasty (TJA), including periprosthetic joint infection and aseptic loosening, can possibly be decreased with proper identification and treatment, which can be elucidated by future high quality studies.