Displaced femoral neck stress fractures in Royal Marine recruits--management and results of operative treatment.

Femoral neck stress fractures (FNSF) represent 3.5%-8% of stress fractures in military recruits; potentially resulting in medical discharge and/or complications. The incidence of displaced FNSF in the British Army has been reported as 1.8 in 10,000 recruits. We aimed to review the incidence and outcome of displaced FNSF in Royal Marine recruits. Retrospective review identified 6 recruits who sustained a displaced FNSF from 2001 to 2011 representing an incidence of 9.3 in 10,000 recruits. All were treated urgently by internal fixation. There were no cases of avascular necrosis, no surgical complications and no further procedures required. All united with a mean time to union of 11 months. 50% had a union time greater than 1 year. These fractures are slow to unite but with urgent surgical intervention and stable fixation 100% union was achieved. Awareness of this guides the management and rehabilitation whilst avoiding the risks of unnecessary secondary surgical interventions.