Medical Clues Include Prior Symptoms, Location Of Thigh Bone Break, And Specific Radiology Findings
(Posted by Tom Lamb at DrugInjuryWatch.com)
For this medical primer about femur fractures which might be associated with Fosamax as well as the several other bisphosphonate osteoporosis medications available in the U.S. we will start with some basic anatomy taken from a document titled "Femur Shaft Fractures (Broken Thighbone)", published by the American Academy of Orthopaedic Surgeons (AAOS):
Your thighbone (femur) is the longest and strongest bone in your body. Because the femur is so strong, it usually takes a lot of force to break it. Car crashes, for example, are the number one cause of femur fractures.
The long, straight part of the femur is called the femoral shaft. When there is a break anywhere along this length of bone, it is called a femoral shaft fracture....
Doctors describe fractures to each other using classification systems. Femur fractures are classified depending on:
The location of the fracture (the femoral shaft is divided into thirds: distal, middle, proximal)
The pattern of the fracture (for example, the bone can break in different directions, such as cross-wise, length-wise, or in the middle)
Whether the skin and muscle above the bone is torn by the injury
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We move next to a recent medical journal article, "Bisphosphonate-Related Complete Atypical Subtrochanteric Femoral Fractures: Diagnostic Utility of Radiography", which was published in the October 2011 edition of the American Journal of Roentgenology (AJR). From the Abstract of this medical article:
OBJECTIVE. The objective of our study was to evaluate the diagnostic utility of conventional radiography for diagnosing bisphosphonate-related atypical subtrochanteric femoral fractures.
MATERIALS AND METHODS. Retrospective interpretation of 38 radiographs of complete subtrochanteric and diaphyseal femoral fractures in two patient groups—one group being treated with bisphosphonates (19 fractures in 17 patients) and a second group not being treated with bisphosphonates (19 fractures in 19 patients)—was performed by three radiologists....
CONCLUSION. Radiographs are reliable for distinguishing between complete femoral fractures related to bisphosphonate use and those not related to bisphosphonate use. Focal lateral cortical thickening and transverse fracture are the most dependable signs, showing high odds ratios and the highest accuracy for diagnosing these fractures.
Returning briefly to the the AAOS document that we started with for quick definitions of one term used above and two other terms referenced below:
Transverse fracture. In this type of fracture, the break is a straight horizontal line going across the femoral shaft.
Oblique fracture. This type of fracture has an angled line across the shaft.
Comminuted fracture. In this type of fracture, the bone has broken into three or more pieces. In most cases, the number of bone fragments corresponds with the amount of force required to break the bone.
Now we go back several months to the June 2011 edition of the Drug Safety Update published online at the Medicines and Healthcare products Regulatory Agency (MHRA) web site for a piece entitled "Bisphosphonates: atypical femoral fractures".
To facilitate future case reporting and research, the European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) has adopted a definition of atypical femoral fracture based on the American Society for Bone and Mineral Research (ASBMR) provisional case definition of atypical femoral fracture1—major and minor features:
~ Located anywhere along the femur from just distal to the lesser trochanter to just proximal to the supracondylar flare
~ Associated with no trauma or minimal trauma, as in a fall from a standing height or less
~ Transverse or short oblique configuration
~ Complete fractures extend through both cortices and may be associated with a medial spike; incomplete fractures involve only the lateral cortex
~ Localised periosteal reaction of the lateral cortex [often referred to in radiology reports as ‘beaking’ or ‘flaring’]
~ Generalised increase in cortical thickness of the diaphysis
~ Prodromal symptoms such as dull or aching pain in the groin or thigh
~ Bilateral fractures and symptoms
~ Delayed healing
~ Comorbid conditions (eg, vitamin D deficiency, rheumatoid arthritis, hypophosphatasia)
~ Use of pharmaceutical agents (eg, bisphosphonates, glucocortoids, proton pump inhibitors)
Moreover, this MHRA Drug Safety Update article makes these two important points:
- Specifically excluded are fractures of the femoral neck, intertrochanteric fractures with spiral subtrochanteric extension, pathologic fractures associated with primary or metastatic bone tumours, and periprosthetic fractures.
- All major features are required to satisfy the case definition of atypical femoral fracture. None of the minor features are required, but sometimes have been associated with these fractures.
We hope these medical resources will be of assistance to patients and their families who are trying to determine if a femur fracture that was low-stress or otherwise unusual, e.g., not resulting from a fall, trauma, etc., might be related to the use of bisphosphonate osteoporosis medications like Fosamax.
As always, please submit any Comments you may have about this medical information or about any particular atypical femur fracture situation, below.
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