대퇴골에 발생한 부전 골절의 임상적 고찰

Abstract

Objective: Bisphosphonates have been used as a first line drug to prevent osteoporotic fractures by the mechanism of suppressing bone resorption and thereby increasing bone mass. But some recent studies have reported that the long-term use of bisphosphonates either decreases the mechanical strength of femur, or has a relationship with the low-energy femoral trauma. the purpose of this study is to analyze the insufficiency fractures of femoral shaft in elderly population and to investigate its relationship with bisphosphonates.

Methods:: From January 2002 to June 2008, 8 patients were diagnosed and treated for insufficiency fracture of femoral shaft. Fracture pattern, treatment and the clinical progress of these patients was analyzed.

Results: Among 8 patients of insufficiency fracture of femoral shaft, 3 cases were unilateral fractures and were operated on that side. 2 cases were that of bilateral fractures with fracture of one side being a pseudofracture. These patients were operated only on the side of the true fracture. 2 cases were unilateral fractures associated with cortical hypertrophy on the contra-lateral side and were operated only on the side of fracture. There was 1 case of bilateral femoral shaft fracture and was operated on both sides. the mean bone mineral density of neck of femur was -2.9 (T-score). 5 patients had taken bisphosphonate over 5 years.

Conclusion: An insufficiency fracture occurs when a low-energy trauma is applied on a mechanically weak bone. Generally the stress fracture after slipping down occurs at neck or intertrochanteric area of femur, but the insufficiency fracture of femoral shaft is usually seen at the convex side of the shaft and is characterized by pseudofracture or cortical hypertrophy, simple transverse fracture pattern and medial cortical spike of distal fragment. These characteristics suggest repeated microfracture and remodeling over a prolonged period. Chronic use of bisphosphonate for treatment of osteoporosis may be the cause of insufficiency fracture of femur due to persistent suppression of bone remodeling, so caution is needed in long term use of bisphosphonates.