FEMORAL NECK STRESS FRACTURES IN MILITARY PERSONNEL – A 20 CASE SERIES

Abstract

Femoral neck stress fractures (FNSF) are uncommon, representing around 5% of all stress fractures. In military personnel, FNSF represents one of the severest complications of military training, which can result in medical discharge. Clinical examination findings are frequently non-specific and plain radiography may be inconclusive leading to missed or late diagnosis of FNSF. This paper highlights the significance of FNSF’s 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, UK), over a four-year period from the 1^st July 2002 to 30^th June 2006, who suffered a FNSF. The medical records, plain radiographs, bone scans and MRI’s 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. FNSF’s were most prevalent amongst Parachute Regiment recruits (1 in 250, p< 0.05). Onset of symptoms was most commonly between 13–16 weeks from the start of training. The majority (17/20, 85%) of FNSF’s were undisplaced, these were all treated conservatively. Three FNSF’s were displaced on presentation and were treated surgically. Overall, the medical discharge rate was 40% (8/20). FNSF’s are uncommon and the diagnosis remains a challenge to clinicians and requires a high index of suspicion in young athletic individuals. In such individuals early referral for MRI is recommended, to aid prompt diagnosis and treatment, to prevent serious sequelae.

Correspondence should be addressed to Major M Butler RAMC, Princess Elizabeth Orthopaedic Centre, Royal Devon and Exeter Hospital, Exeter, Devon.