This study evaluates the effect of Vitamin D3 supplementation in healing rate of tibia fractures in adult patients with low vitamin D. Half of participants will receive Vitamin D3 supplementation while the other will receive placebo.

Inclusion Criteria:

• Tibial fracture
• ASA physical status classification system I-II.
• 25 hydroxyvitamin D below 30ng/ml)
• Fracture treatment with reamed intramedullary nail

Exclusion Criteria:

• Open Fractures Gustillo III B and III C
• Closed Soft tissue injury with Tscherne classification of III
• Acute Compartment Syndrome
• Pathology fractures (That occur in abnormal bone, for example in the presence of tumor, cyst or Paget disease)
• Other Fractures in lower limbs or spine that does not allow full weight bearing of the operated tibia after 4 weeks
• More than 7 days of evolution from fracture occurrence
• Diabetes mellitus with HbA1c more or equal than 7%
• Peripheral vascular disease
• Rickets
• Pre-existing disorders of the metabolism of Vitamin D and/or homeostasis of calcium and phosphorous (ie. Hepatic insufficiency, congenital defects of the vitamin D metabolism, disorders of the parathyroid glands, hypo or hyper calcemia)
• Renal failure with glomerular filtration rate below 60ml/min according to MDRD-4.
• Patients using nephrotoxic medications in high doses, requiring periodical monitoring of glomerular filtration rate
• Patients undergoing with nephrotic syndrome or that suffered it in the past
• Patients that suffered nephrolithiasis or urolithiasis
• Pregnant women
• Patients with allergy to vitamin D or other contraindications for vitamin D3 prescription
• Patients that are taking multivitamin supplements containing vitamin D and will not suspend taking them during the study.
• Patients that are not able to swallow a cup of water