Vitamin D Management and Nonunion in Elective Foot and Ankle Arthrodesis
Authors: Ebben Benjamin J. , Brooks Andrew E. , Gaio Natalie M. , Williams Kathryn L. 
Published: March 2021

Category: Other; Ankle; Ankle Arthritis; Bunion; Hindfoot; Midfoot/Forefoot Introduction/Purpose: Bone health and more specifically, vitamin D status, have become a focus across multiple orthopedic subspecialties as a modifiable determinant of health. Improved bone health and nutritional optimization can function preventatively by curtailing problems such as osteoporotic fractures but can also function to optimize operative outcomes contingent upon successful bone-to-bone healing, such as arthrodesis. Investigations on this topic are relatively lacking in the orthopedic foot and ankle literature and to date, are limited mostly to epidemiologic study designs that have reported on prevalence of hypovitaminosis D. To the best of our knowledge, there have been no attempts to associate vitamin D status with nonunion and no inquiries into the perioperative management strategies for hypovitaminosis D in the elective foot and ankle arthrodesis population. Methods: Records from all elective foot and ankle arthrodesis procedures performed by the senior author between 2013 and 2019 were obtained. These procedures ranged in complexity from single joint hallux interphalangeal arthrodesis to multiple joint deformity correction arthrodesis. It has been standard practice for the senior author to obtain a preoperative vitamin D level on all patients indicated for arthrodesis and treat accordingly during the perioperative period for cases of hypovitaminosis D (<30 ng/mL). We retrospectively reviewed the medical records for a total of 113 arthrodesis procedures. We recorded patient demographics, comorbidities, BMI, arthrodesis type, vitamin D level, perioperative vitamin D supplementation and the outcome as union or nonunion. We reviewed all postoperative radiographs and computed tomography when available. We defined nonunion as reoperation or planned reoperation for revision arthrodesis or definitive clinical or radiographic evidence of nonunion with ongoing symptomatic treatment. All other cases were considered to have achieved union. Results: A total of 113 arthrodesis procedures (105 patients) were reviewed. The mean preoperative vitamin D level was 33. Vitamin D levels were normal in 56.6% (64/113) of patients. Forty-nine patients had hypovitaminosis D. Thirty-two (28.3%) were considered insufficient and the other 17 (15.1%) deficient (<20 ng/mL). All patients with hypovitaminosis D were prescribed a 4- week regimen of ergocalciferol during the perioperative period and then maintenance doses, thereafter. Of the 113 procedures, 106 (93.8%) were determined to achieve union by the time of last follow up. There were 7 (6.2%) nonunions. Patients treated for hypovitaminosis D went on to achieve union at a rate of 93.9% (46/49) which was similar to the union rate of 93.8% (60/64) observed in patients with normal preoperative vitamin D levels. Conclusion: The prevalence of hypovitaminosis D in this population was high but consistent with previous literature in foot and ankle patients. The overall nonunion rate of 6.2% was also consistent with previous investigations. We found no difference in union rate when including all elective foot and ankle arthrodesis procedures between patients with preoperative hypovitaminosis D and those with normal vitamin D levels. The perioperative vitamin D management protocol employed by the senior author appears to be an effective approach for nonunion risk modification. Hypovitaminosis D, alone, should not be a reason to deny or delay elective foot and ankle arthrodesis surgery.