The incidence of DVT and need for thrombo-prophylaxis following isolated distal lower extremity fractures is unknown. The purpose of this study was to determine whether or not thrombo-prophylaxis with low molecular weight heparin was needed in this trauma population.

A Multicentered Prospective Randomised Double Blind Placebo Controlled Trial was designed to define the incidence of DVT and need for thrombo-prophylaxis in this population. A sample size of two hundred and ninety-nine patients ensured a one tailed type one error of alpha = 0.05 and power of 80% as confirmed from previous studies. Males and female patients between the ages of eighteen and seventy-five years with isolated distal lower extremity fractures (excluding the foot) were eligible. All patients had surgery within forty-eight hours after injury. Patients excluded from the trial were polytrauma patients, those medically unfit for the operating room, patients with foot fractures, those receiving anticoagulation, inability to provide consent, platelets 200 umol /L. Randomization was carried out via computer generation to receive either placebo or Fragmin for fourteen days. At fourteen days, all patients underwent bilateral venograms interpreted by three independent radiologists. Equivocal venograms were interpreted by consensus. Routine follow-up was carried out for all patients at two, six, eight and twelve weeks.

A total of two hundred and ninety-nine patients were enrolled in the study. One hundred thirty-six patients in the Fragmin group and one hundred and twentyfive in the placebo group completed the intervention. There were one hundred and twenty-five males and one hundred and thirty-six females in total. There was no statistically significant difference in DVT incidence between those patients treated with Fragmin or Placebo (p = 0.41). Gender, medical issues, pre-operative level of activity and body mass index had no effect on the incidence of DVT.

The incidence of DVT in fragmin treated and placebo treated patients is 8.1% and 11.2%, respectively (p = 0.41). This study suggests that DVT thrombo-prophylaxis is not indicated in this patient population. To our knowledge, this is the first Randomised Controlled Trial utilizing venograms (gold standard) for DVT identification.