Working Diagnosis:
Stress fracture of the proximal femur

Treatment:
Upon diagnosis of a femoral stress fracture the athlete was immediately placed on activity restrictions. This included no running or any activity that involved impact. He was allowed to fully weight bear with walking as this was not painful. He underwent a stepwise return to activity protocol that was guided by his symptoms and general standards of care. A four phase treatment schedule, similar to that proposed by A. Ivkovic et al, in their 2006 publication in which seven athletes with femoral shaft stress fractures were treated, was employed. This include non weight bearing in phase 1, weight bearing and swimming in phase 2. Phase 3 included stationary bicycling and alternate day straight runs. Phase 4 was resumption of regular activity. Each phase lasted approximately 3 weeks. Our athlete was started at phase 2 with stepwise return to activity. X-ray performed at the end of rehabilitation confirmed a healed proximal shaft fracture on the compression side.

Author's Comments:
Stress fractures are common injuries seen in the running athlete. Femoral stress fractures are rare occurrences and account for 7-8% of stress injuries [1,2]. Fractures of the proximal femoral shaft are found to occur at a rate of 18% of all femoral stress fractures [4]. The average time to diagnosis ranges from 13-14 weeks [1] when radiographs, bone scan and computer tomography are the only available investigative tool. With the advent of magnetic resonance imaging, the increase sensitivity and specificity permits earlier diagnosis and better delineation between the causes of hip pain [3]. The following case highlights the complexity of arriving at a diagnosis when assessing hip pain in endurance runners and the need to have a high clinical suspicion for stress fractures.
A high index of suspicion is required when evaluating hip and thigh pain in endurance athletes. Stress fractures of the femur are associated with increase morbidity when missed. Stress fractures of the neck of femur are the most common and carry the highest risk of complications when undiagnosed [4,7]. The proximal shaft remains the least common of the stress fracture types of the femur 4. There is an increase susceptibility to sub-maximal repetitive forces at the junction of the proximal and middle third of the femur [5]. Stress fractures of long bones and pelvis are more likely to occur in middle and long distance runners [2]. The symptoms are usually vague and the physician will need to rely on specialize testing to assist in making the diagnosis. Two test employed include the fulcrum and one leg hop tests. In this athlete, the one leg hop test was positive and the fulcrum test was negative. Risk factors such as previous stress fracture, increase in training volume, medication use that alter bone metabolism, limb length differences, lower bone density and lower caloric intake have been associated with stress fractures [8]. In the evaluation of this athlete, magnetic resonance imaging was the investigation of first choice due to the high sensitivity and specificity in comparison to x-ray and triple phase bone scan.

References:
1.Stress Fractures in Athletes, a Study of 320 Cases, Am J Sports Med, Jan 1987, vol 15 (46-58) Mattheson G.O., Clement D.B., McKenzie D.C. et al
2.The Incidence and Distribution of Stress Fractures in Competitive Track and Field Athletes, a Twelve-Month Prospective Study, Am J Sports Med, Mar 1996, vol 24 (2) Bennell K.M., Malcolm S.A., Thomas S.A. et al
3.The superiority of magnetic resonance imaging in differentiating the cause of hip pain in endurance athletes, Am J Sports Med, Mar 1996, vol 24 (168-176) Shin A.Y., Morin W.D., Gorman J.D. et al
4.Fatigue Injuries of the Femur, J Bone Joint Surg Br 2005; 87(10): 1385-90, Niva N.H., Kiuru M.J., Haataja R. et al
5.Stress fractures of the femoral shaft in athletes: a new treatment algorithm. Ivkovic A., Bojanic I., Pecina M. et al, Br J Sports Med 2006; 40: 518-520
6.Femoral Stress Fracture, Casterline M., Osowski S., Ulrich G. et al. Journal of Athletic Training, March 1996, vol 31 (1): 53-56
7.Fatigue stress injuries of the pelvic bones and proximal femur: evaluation with MR imaging, Eur Radiol 2003 Mar; 13(3)605-11. Kiuru M.J., Pihlajameki H.K., Ahovuo J.A. et al
8.Risk factors for stress fractures, Sports Med Aug 1999; 28(2):91-122. Bennell K., Matheson G., Meeuwisseo W et al

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