Bilateral concomitant femoral neck stress fracture in a sede
Anorexia nervosa (AN) is a disorder characterized by severe weight loss, fear of obesity and partial self-starvation. Most commonly found in women but increasing in men, it is currently the third most frequent chronic disease in adolescents. Orthopedic implications include a significant and sometimes permanent loss of bone stock, with a corresponding increase of fracture risk, including stress fractures. The two main causes of reduction of bone density in AN are body composition changes and hormonal alterations.

The patient was a 27 year-old woman, that had never engaged in any sport activity. A history of smoking, on psychiatric medication due to panic attacks and chronic eating disorders which resulted, 5 years before admission for the fractures, in a BMI of 16.6 kg/m2 and amenorrhea. For a 5-year period her diet consisted of cookies, coffee and cigarettes. She partially modified this conduct 2 years before admission, when she weighed 62 kg and with regular menstrual periods, which confirmed that the patient had clinically recovered from AN.
She presented mild to moderate bilateral groin pain for 18 months, starting when she initiated weight gain. At this time she would not recognize her alimentary disorder and denied the previous AN condition.

Standard radiographs showed a calcar compression fracture in both hips (Fig. 1) and MRI showed a change of intensity in both femoral necks and bone oedema in the right, suggesting a compressive non displaced fracture at the inferior aspects of both femoral necks. The bone scan revealed an increase uptake of both femoral necks, also suggesting bilateral SF, and finally, a CT scan confirmed the fracture in both hips.
Blood tests showed values for serum total proteins of 5.7 g/dl , albumin of 3.2 g/dl and vitamin D of 16.4 ng/ml .
Using a minimally invasive procedure, bilateral internal fixation with a DHS was performed. During surgery, 2 bone biopsies for histological analysis were taken. The patient was started with partial weight-bearing with a walker the day after surgery and was treated with vitamin D, calcium and a special diet.
The histological analysis informed normal bone.

The patient suffered a fall 3 days after surgery as a result of walking without assistance when going to the bathroom and sustained a fracture of the left femur just below the DHS.
A new internal fixation with a proximal femoral nail was performed and, as the patient had not previously followed the walking instructions and to prevent a new fall, a non-weight bearing non-walking period of 3 weeks was enforced. Three months after surgery, the distal dynamic screw had reached its maximum sliding capacity and was removed to improve fracture site compression.

At 8 months after surgery, X rays showed the healing progression of the fractures. The patient was deeply depressed and aggressive, walked indoors only, referring moderate bilateral generalized lower limb pain and using 1 cane. The author then again emphasized the need for psychological and psychiatric assistance, to which she was initially reluctant and finally accepted. At 13 months after surgery, the patient walked with no assistance or pain, and the fractures were healed.

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