Martí Bernaus MD1, Brad Petrisor MD MSc2, Sofia Bzovsky MSc2, and Sheila Sprague PhD2,3 1 Department of Orthopedic Surgery, Hospital Universitari Mútua Terrassa, Barcelona, Spain 2 Division of Orthopaedic Surgery, Department of Surgery, McMaster University, Hamilton, ON, Canada 3 Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada Over the weekend, you operatively treat two patients with femoral neck fractures. During rounds on Monday morning, you follow up with the patients with a new surgical resident. You both walk into the first wardroom and differences in body mass index (BMI) and nutrition status between the two patients do not pass unnoticed. One patient is obese and the other shows signs of undernutrition. Your resident then starts asking questions… Vitamin D and calcium are well known to be necessary for building and maintaining bone strength and preserving skeletal health across all ages.1,2 Individuals obtain vitamin D from exposure to sunlight or by consuming foods that contain vitamin D, while calcium is primarily retrieved from dairy products.1,3 It can be difficult to obtain adequate vitamin D and calcium from these sources alone, especially since sun exposure levels vary depending of the latitude, season, time of day, skin pigmentation, cloud cover, smog, and sunscreen use, so individuals often also derive vitamin D and calcium from supplements.1,3,4 Although Health Canada recommends that adults take a daily vitamin D supplement of between 600–800 IUs, vitamin D deficiency and insufficiency are prevalent and recognized as worldwide health problems.1,5 The role of calcium in the pathogenesis of osteoporosis has received increasing attention and the recommended amounts for calcium intake have risen steadily in the past 35 years.6 This is mainly because calcium deficiency activates bone destruction through bone resorption mechanisms. The use of prevention therapies, such as vitamin D and calcium supplementation, aims to maintain and improve bone quality and minimize fractures. Osteoporosis and osteopenia are highly prevalent among fracture patients.7 As well, there is uncertainty and a lack of consensus in the use and dosing of vitamin D and calcium supplementation. Although the US Institute of Medicine and Health Canada have released dietary reference intakes for vitamin D and calcium. To the best of our knowledge, there are no widely accepted clinical guidelines on supplementation in an orthopedic fracture care practice.1,2 Pre‐appraised research information was obtained using the OrthoEvidence database of randomized trials. Further, meta‐analyses consisting of level I evidence randomized controlled trials (RCTs), level II and III evidence prospective and retrospective comparative studies, as well as level IV evidence case series, and cross‐sectional studies, have been published that address our question.8,9 Vitamin D deficiency is endemic worldwide in all subsets of orthopedic patients, and osteoporosis is commonly found in those patients with fractures. Although most experts define vitamin D deficiency as levels <20 ng/mL and insufficiency as 21–29 ng/mL, there is no universal agreement for these cutoffs.10 Based on these definitions, approximately 75% of the general population have serum 25‐hydroxyvitamin D (25[OH]D) levels below 30 ng/mL.11 One study on orthopedic trauma patients with acute fractures reports overall prevalence rates for combined vitamin D deficiency or insufficiency of 77% and a 39% prevalence rate for vitamin D deficiency alone.12 It has also been suggested that the prevalence of vitamin D inadequacy, defined by the authors as serum 25(OH)D levels <32 ng/mL, in athletes is prominent.11 Weaver et al. have conducted an updated meta‐analysis of vitamin D and calcium supplementation which suggests that the combination of vitamin D and calcium supplementation is statistically significantly associated with reduced fracture risk.9 Further results from this meta‐analysis suggest that supplementation could decrease the relative risk of fractures by 14% (relative risk [RR] = 0.85; 95% confidence interval [CI] 0.73–0.98).9 However, a meta‐analysis by Zhao et al. showed no significant association of calcium or vitamin D (alone or combined) with reduced risk of hip, vertebral, or other fractures in community‐dwelling older adults.13 Also, calcium supplementation alone has not been demonstrated to reduce the rate of fractures in elderly women.14 Data on the effects of vitamin D and calcium supplementation on fracture healing are limited. Briefly, research suggests that vitamin D supplementation safely increases 25(OH)D serum levels and improves bone mineral density.8 To date, there has only been one preliminary study, presented as an abstract at a meeting, which reported a trend toward lower nonunion rates in acute fracture patients receiving vitamin D supplements.15 Additionally, there is emerging, but inconclusive, evidence that vitamin D levels decrease following a fracture16–20 and it has been hypothesized that postfracture vitamin D supplementation alone, and possibly in combination with oral calcium supplementation, may improve fracture healing.21–23 However, although limited, there is some evidence suggesting that dietary calcium intake is associated with cardiovascular risk. Any benefit of calcium supplements on preventing fractures may be outweighed by increased cardiovascular events, more specifically myocardial infarction and stroke.24 As evidence regarding the use of these therapies has shown inconsistent results, there is a need for more high‐quality research to be conducted in this area. Vitamin D supplementation typically leads to increased levels of serum 25(OH)D. The most well‐known risk of increased 25(OH)D is hypercalcemia, which occurs secondary to increased calcium intestinal absorption and bone resorption.25 However, evidence that excess vitamin D can cause hypercalcemia in generally healthy adults comes from daily intakes of vitamin D >100 000 IU or having levels of serum 25(OH)D exceeding 240 nmol/L (96.15 ng/mL), which is far higher than that necessary to achieve the benefits.26 The side effects reported after receiving calcium therapy have been an important drawback for its use. Constipation, excessive abdominal cramping, bloating, upper gastrointestinal (GI) events, GI disease, GI symptoms, and severe diarrhea or abdominal pain were described in a meta‐analysis by Lewis et al.27 More importantly, hospital admissions for GI complaints were higher in calcium‐treated patients (6.8%) compared to those who obtained a placebo (3.6%) (RR = 1.92; 95% CI: 1.21–3.05; p = 0.006). It has also been reported that the use of calcium supplementation may be associated with increases in urine calcium excretion.28 In the Women’s Health Initiative Calcium/Vitamin D Supplementation Study, there was found to be an increased risk of renal calculi following calcium supplementation.29 Regarding cardiovascular events, an RCT of calcium supplementation compared to placebo in healthy postmenopausal women showed a statistically significant increase in the number of women who had a myocardial infarction in the calcium treatment group (RR = 2.24; 95% CI: 1.20–4.17; p = 0.0099).25 These effects could outweigh benefits that calcium supplements may have on bone health. The prevalence of obesity, defined as a BMI of ≥30 kg/m2, has tripled since 1975, with 650 million adults being reported as obese globally in 2016.30 Obesity is leading to an increased use of the healthcare system.31 Obese individuals often have multiple co‐morbidities and are therefore at a higher risk for perioperative complications.32 Co‐morbidities associated with obesity include type 2 diabetes mellitus, hypertension, dyslipidemia, cardiovascular disease, stroke, sleep apnea, hyperuricemia, gallbladder disease, gout, osteoarthritis, and certain cancers.33 Orthopedic patients who are obese may be at a higher risk of both general medical and fracture‐related complications. Specific intraoperative and perioperative challenges and complications have also been associated with obesity, including the requirement of special surgical equipment, longer operating times, potentially significant anesthetic issues, as well as a longer postoperative length of stay.34 From a biomechanical point of view, postoperative rehabilitation may prove difficult as well, as there may be an increase in stress on orthopedic implants with subsequent possible failure of fixation or mechanical failure of the implant itself.35–38
17 Nutrition and Supplements in Orthopedic Care
Clinical scenario
Top three questions
Question 1: In orthopedic surgery patients, do vitamin D and calcium supplementation, compared to no supplementation, confer a benefit in terms of fracture risk, fracture healing, or bone mineral density?
Rationale
Clinical comment
Available literature and quality of the evidence
Findings
Vitamin D deficiency in orthopedic patients
Vitamin D and calcium supplementation for osteopenia and osteoporosis
Vitamin D supplementation and fracture healing
Risks of vitamin D and calcium supplementation
Resolution of clinical scenario
Question 2: Among patients undergoing orthopedic surgery, do those with a high BMI have a higher risk of complications compared to those with a normal BMI?
Rationale
Clinical comment
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