PURPOSE: Increasing numbers of atypical femoral fractures have been reported
among long-term bisphosphonate users. We evaluated clinical characteristics of
atypical femoral fractures throughout Korean multicenter studies. METHODS: We
retrospectively analysed the bone mineral density, prodromal symptoms before
femoral fracture, and medication history of osteoporosis in 76 cases of atypical
femoral fracture. RESULTS: The mean age of cases was 71.4 +/- 8.8 (range, 43-89)
years old. The mean follow-up period after the fracture operation was 24.5 +/-
12.9 (range, 12-79) months. BMI was 23.2 +/- 3.0 on average. The mean BMD of
femur was -1.9 +/- 1.4 (range, -4.8 to 1.3). Prodromal symptoms including thigh
pain before femoral fracture appeared in 22 (28.9 %) of 76 patients. All patients
included in the study used bisphosphonate. The duration of taking bisphosphonate
before fracture was 36.8 +/- 50.8 (one-204 months) months. Fifty-seven (75 %) of
76 patients were taking the medication for more than three years. Delayed union
occurred in 43 (56.5 %) of 76 patients. Delayed union was defined as a fractured
bone that did not completely heal within six months of injury. The group of
having taken anti-osteoporotic medication for more than three years showed
relatively longer union period compared to that for a shorter period medication
group (4.8 +/- 2.5 months vs 9.3 +/- 3.7 months, p = 0.017). The delayed union
developed in 43 (56.5 %) of 76 patients and showed a significantly higher
incidence in the group with long-term therapy (five/43 vs 38/43, p = 0.021). The
bilateral femoral fractures developed in 23 (30.2 %) of 76 patients and showed a
high incidence in the group medicated more than three years (two/23 vs 21/23, p =
0.039). CONCLUSIONS: The longer bisphosphonates are used, the more the cases of
delayed union and the more frequent the development of bilateral fractures
following unilateral fractures. With regard to the delayed union, the methods of
the acceleration of fracture healing may be beneficial in atypical femoral
fracture patients who had been receiving long-term bisphosphonates therapy.
Careful observation is required for contra-lateral femurs due to a high incidence
of bilateral atypical femoral fractures
