When A Vitamin D Deficiency Complicates Bunion Surgery

With a look at the current research, this author offers insights on addressing the bone healing issues resulting from vitamin D deficiency in a 19-year-old patient with bunions.

The importance of vitamin D in bone health has long been established.1 Consequently, a lack of vitamin D in the diet or lack of sun exposure may lead to serious health problems such as osteomalacia, rickets, certain cancers, diabetes, heart disease and even mortality risk in women. Unfortunately, vitamin D deficiency and its known consequences are a global concern.2 Studies have implicated sedentary lifestyles, climate, sunscreen/protective clothing and other factors as causative.1,2

   Bone healing in healthy middle-aged and younger people does not frequently come to mind when planning foot and ankle surgery, unless there are documented reasons for this to occur. These reasons include smoking, a prior history of delayed or nonunion, a prior history of vitamin D deficiency/insufficiency, documented non-adherence or osteogenesis imperfecta.

   In more recent years, there have been studies regarding the screening of vitamin D levels preoperatively not only in adults but also in children.3,4 With our profession’s many years of collective surgical experience in bone and joint surgery, it is astounding that only recently is so much attention focusing on a seemingly simple issue.

   In the fall of 2011, I attended the Texas Podiatric Medical Association Conference in Frisco, Texas, at which Laurence Rubin, DPM, presented a lecture on the screening of patients prior to osseous foot and ankle surgery.4 This workup included a 25(OH) vitamin D level and a 24-hour urine calcium level as well as the possibility of hormone testing. This was not the first occasion I had either discussed or listened to discussions on vitamin D importance, but this was the first time I had noted it extrapolating to podiatry.

   Based upon this sound advice, I had started to screen patients who were more likely to be at risk for Vitamin D deficiency including women who were post-menopausal, post-hysterectomy or older. For young healthy individuals with no prior history, it seemed a waste of resources to test for this preoperatively just as it is not necessary to have a preoperative chest X-ray or electrocardiography in young, healthy individuals per anesthesia algorithms. There are not standardized criteria in place for bone health testing in foot and ankle surgery.

A Closer Look At The Patient Presentation And Treatment

A 19-year-old female presented to my office for long-term complaints of bunion pain on her left foot. She had been using wide shoes, accommodative padding and sandals to avoid the pain. The patient had reached the point where her foot was painful with walking, even in open-toed shoes. This prompted her to seek surgical consultation for correction. Her past medical and surgical histories were unremarkable for significant pathology. The patient denied any smoking, alcohol or illicit substance abuse. Family history and review of systems were non-contributory to her chief complaint.

   The physical examination demonstrated a significantly increased intermetatarsal angle and hallux abductus angle. The proximal articular set angle was greater as was the tibial sesamoid position. The range of motion at the first metatarsophalangeal joint (MPJ) was restricted with track-bound range of motion and palpation tenderness. Radiographs confirmed the gross findings. There was no evidence of osteopenia or osteoporosis on radiograph.

   My plan for this patient was a closing base wedge osteotomy with Juvara angular modification to correct/prevent elevatus. It was also possible that a double osteotomy may be needed to correct the proximal articular set angle intraoperatively.

   My typical fixation for this type of procedure is a combination of lag and anchor screws at the base wedge osteotomy (using metal screws) and bioabsorbable fixation of a Reverdin-Green-Laird osteotomy of the metatarsal head (if necessary). The preoperative workup for this patient included a complete blood count with differential, basic metabolic panel and pregnancy testing.

   At the time of surgery, I employed a standard longitudinal incision at the dorsomedial aspect of the first ray. In performing double osteotomies of the first metatarsal, take care not to interrupt the nutrient artery at the proximal medial shaft. One should also avoid denuding or aggressively dissecting the periosteum as this is a known reason for osteotomy failure. I placed an axis guide into the proximal medial cortex of the first metatarsal to prevent dorsal displacement, another known complication of this type of osteotomy. I also used care when placing the osteotomy guide inside of the medial cortical wall in order to prevent hinge breakage.

When One Encounters Poor Bone Quality Intraoperatively

When performing the osteotomy, I realized the bone had some areas that were softer than anticipated. Any surgeon who has worked on young individuals has experienced the usual good bone quality and pliability of osteotomy hinges. Personally, I have even foregone the anchor screw in healthy younger women when the hinge was strong and the lag screw reduced the osteotomy sufficiently.

   As I removed the axis guide and wedge, I closed the base wedge osteotomy site with bone reduction forceps. However, to my dismay, I heard a snapping sound akin to peanut brittle breaking. In my experience, this is not uncommon in middle-aged to older individuals but I had never experienced this with such a young female patient. Breaking the hinge of a closing base wedge osteotomy certainly has its own challenges in fixation. However, as I tried to place the anchor and lag screws, I found additional areas of poor bone quality, necessitating three points of fixation. If a locking plate had been available, this would have been a better choice for fixation.

   Immediately in the recovery room, I requested a 25(OH) vitamin D level testing. This indeed confirmed my suspicion of vitamin D deficiency. She started on a regimen of vitamin D 50,000 IU/week. Her postoperative course was prolonged due to fear of metatarsal/osteotomy fracture in the case of an early return to weightbearing. I deferred her weightbearing until she was between weeks six and eight postoperatively. While her bone was improved at that time, there had also been a delay for range of motion as well. This caused difficulties including pain and altered gait in the third and fourth postoperative months.

What You Should Know About Vitamin D Deficiency

Vitamin D insufficiency is defined as 25(OH) vitamin D levels less than 30 ng/mL, and vitamin D deficiency occurs when levels are <20 ng/mL. In this case, the level immediately after the procedure was approximately 19 ng/mL, which is in the range of deficiency according to the most recent definition.6 Algorithms exist to help guide vitamin D replacement and supplementation as well as monitoring of levels in the affected patient.7 One should exercise caution with Vitamin D replacement so as not to cause hypervitaminosis D. The oil soluble vitamins (A, D, E and K) all have a risk of excess accumulation/toxicity.

   Subsequent monitoring of patients under treatment should occur between two and three months after initiating therapy. Of course, one should notify the patient’s primary care physician of the findings and he or she should be allowed to manage the replacement (and subsequent long-term maintenance) if desired.

   In this case, there were some warning signs that we missed. These signs were pale skin color, a sedentary lifestyle and a lack of exposure to sunlight through exercise or physical activity. Also, she stated that she used sunscreen or wore long sleeves when going outside for longer periods of time.

   Over the past year, in addition to this case, I have now had several other young patients with similar bone healing issues including a 21-year-old with delayed union of a bone graft and a multitude of teenagers and 20-year-olds with delayed fracture healing or the appearance of stress fractures, which would not be expected in this population. There was also a 12-year-old with a stress fracture who had a vitamin D level of 12 ng/mL.

   The debate/argument with dermatologists is ongoing about how much sun exposure is “safe.” Currently, the best recommendations are for 30 minutes of exposure each day without sunscreen between the hours of 10 a.m. and 3 p.m. Unfortunately, during times of work, school and winter months, this much exposure might not be possible. One study at Boston College showed a prevalence of vitamin D insufficiency/deficiency in college students to be as high as 67 percent at the end of winter months. Therefore, it is recommended that all people over age 30 take 600 IU/day of vitamin D plus calcium. Elderly individuals over age 70 need an average of 800 to 1,000 IU/day.8

In Closing

Based upon the mounting research, there is a need for prospective studies on Vitamin D deficiency in foot and ankle surgery. Unfortunately, since the problem is so widespread, institutional review boards would have significant issues in approving studies to prospectively test bone healing in individuals as once physicians have proven a deficiency preoperatively, it would be negligent not to treat the condition. The long-term concern for standardized pre-op screening would be whether insurance companies would cover the lab cost without level 1 evidence to support its need.9 The best recommendation at this time is that all patients undergoing osseous surgery should have preoperative screenings for Vitamin D deficiency or insufficiency.

   Dr. Claxton practices in O’Fallon, Ill.

References
1. Holick MF. Vitamin D deficiency. N Engl J Med. 2007; 37(3):266-81.
2. Holick MF, Chen TC. Vitamin D deficiency: a worldwide problem with health consequences. Am J Clin Nutrition 2008; 87(4):1080S-086S.
3. Bogunovic L, Kim AD, Beamer BS, et al. Hypovitaminosis D in patients scheduled to undergo orthopaedic surgery: a single-center analysis. J Bone Joint Surg. 2010; 92(13):2300-2304.
4. Parry J, Sullivan E, Scott, Cooper A. Vitamin D sufficiency screening in preoperative pediatric orthopaedic patients. J Pediatr Orthopaedics. 2011; 31(3):331–333.
5. Rubin L. Vitamin D and calcium deficiencies: From Mount Rushmore and Lady Liberty to my operative patient. Presented at the 2011 Southwest Foot and Ankle Conference, Frisco, TX. Sept. 16, 2011.
6. Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2011; 96(7):1911-1930.
7. Ross AC, Manson JE, Abrams SA, et al. The 2011 report on dietary reference intakes for calcium and vitamin D from the Institute of Medicine: what clinicians need to know. J Clin Endocrinol Metab. 2011; 96(1):53-58.
8. Consensus Report, Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Calcium and Vitamin D. November 30, 2010.
9. Rollins G. Vitamin D Testing – What’s the Right Answer. Clinical Laboratory News. 2009; 35(7). Available at https://www.aacc.org/publications/cln/2009/july/Pages/CovStory1July09.as… . Published 2009. Accessed June 25, 2012.