Femoral neck stress fractures in military personnel--a case series

Femoral neck stress fractures (FNSF) are uncommon, representing 5% of all stress fractures. In military personnel, FNSF represents one of the more severe complications of training, which can result in medical discharge. Clinical examination findings are often non-specific and plain radiography may be inconclusive--leading to missed or late diagnosis of FNSF This paper highlights the significance of FNSFs in military personnel and alerts physicians to the potential diagnosis. We identified all military recruits, aged 17 to 26, who attended the Infantry Training Centre (Catterick, U.K.), over a four-year period from the 1st July 2002 to 30th June 2006, who had suffered a FNSF. The medical records, plain radiographs, bone scans and MRIs of the recruits were retrospectively reviewed. Of 250 stress fractures 20 were of the femoral neck; representing 8% of all stress fractures and an overall FNSF rate of 12 in 10,000 military recruits. FNSFs were most prevalent amongst Parachute Regiment recruits (1 in 250, p < 0.05). Onset of symptoms was most commonly between weeks 13-16 of training. The majority (17/20, 85%) of FNSFs were undisplaced, these were all treated conservatively. Three FNSFs were displaced on presentation and were treated surgically. Overall, the medical discharge rate was 40% (8/20). FNSFs are uncommon and the diagnosis remains a challenge to clinicians and requires a high index of suspicion in these young athletic individuals. In such individuals early referral for MRI is recommended, to aid prompt diagnosis and treatment and to prevent more serious sequelae.