The Role of Vitamin C in Orthopedic Trauma and Bone Health
Vitamin C is an essential micronutrient with an adult daily recommended intake of 75 mg for women and 90 mg for men. Smokers should consume an additional 35 mg per day because of the increased oxidative stresses from cigarette smoke.
Observational data support the hypothesis that high dietary intake and supplementation with vitamin C may reduce the risk of hip fractures in postmenopausal women.
Results of 2 high-quality trials support use of vitamin C 500 mg daily for 50 days as prophylaxis against complex regional pain syndrome after wrist fracture treated conservatively and operatively. Observational evidence exists for similar treatment after foot and ankle surgery.
The role of vitamin C in preventing osteoarthritis has tremendous potential, though results in animal and human studies are controversial. The heterogeneous results and the lack of prospective trials preclude any recommendation at this time.
Osteoarthritis
Damage caused by free radicals has long been thought to play an important role in osteoarthritis (OA).65-67 A cross-sectional study in knee OA found that amounts of joint fluid antioxidants were lower in patients with severe arthritis than in those with intact cartilage, further implicating free radicals in the pathophysiology of OA.68 Use of vitamin C for prophylaxis against development or progression of OA is therefore a hot research topic. Thus far, animal studies have had mixed results—several showing a chondroprotective effect of vitamin C69,70 and others finding either no effect or even a positive association with the development of arthritis.71
The literature on human subjects, chiefly observational studies, is just as controversial. Wang and colleagues40 found vitamin C intake associated with both a 50% risk reduction of bone marrow lesions on magnetic resonance imaging over a 10-year interval (OR, 0.5; 95% CI, 0.29-0.87) and inversely associated with the tibial plateau bone area. Similarly, the Clearwater Osteoarthritis Study, which followed 1023 patients (age, >40 years), showed that participants who took vitamin C supplements were 11% less likely to develop radiographic evidence of OA (RR, 0.89; 95% CI, 0.85-0.93).72 Nonetheless, other studies have failed to show such associations73 or have demonstrated the opposite effect. Chaganti and colleagues74 analyzed levels of vitamins C and E in the Multicenter Osteoarthritis Study (MOST) cohort of 3026 men and women (age, 50-79 years) and found higher vitamin levels were not protective against incidence of radiographic whole-knee OA and may even have been associated with increased risk.
Conclusion
Vitamin C is an essential micronutrient and a powerful water-soluble antioxidant in numerous biochemical pathways that influence bone health. It has been implicated in the biology of fracture healing, and vitamin C supplementation has been proposed as prophylaxis against hip fractures based on observational data. Results of 2 high-quality double-blind randomized trials support use of vitamin C as prophylaxis against CRPS in wrist fractures treated conservatively and operatively; the evidence for foot and ankle surgery is weaker. Use of vitamin C in OA prevention has tremendous potential, though animal and human study results are controversial. Heterogeneous results and lack of prospective trials preclude any recommendation at this time.
