Osteoporosis is the most common metabolic bone disorder, and affects a large portion of the population. Osteoporosis is defined as a decrease in bone mass (specifically bone mineral density). According to the World Health Organization (WHO), a person has osteoporosis if their bone mineral density is 2.5 standard deviations below that of a normal 25 year-old person or if they have a sustained a fracture due to diminished bone mass. Nearly 1 million people in the United sustain a vertebral compression fracture. Although a vertebral compression fracture is generally not as severe as a hip fracture for an elderly person, it is still a very common condition that can be quite disabling and lead to the development of additional orthopaedic and medical problems.
Osteoporosis most often affects postmenopausal women or the elderly. There are two primary types of osteoporosis, and a number of secondary causes in which an identifiable disease is responsible. Postmenopausal osteoporosis affects women six times more often than men, whereas age-associated osteoporosis affects women and men almost equally.
|PRIMARY OSTEOPOROSIS||AGE RANGE||BONE TYPE AFFECTED|
|Type I||Postmenopausal||51- 70 years old||Trabecular bone|
|Type II||Age-Associated||> 70 years old||Trabecular and Cortical bon|
The most important risk factors contributing to osteoporosis are decreased bone mass at the time of skeletal maturity and rapid loss of bone mass after menopause. It is important for a young person to consume adequate amounts of calories and nutrients, especially Calcium and Vitamin D, and engage in regular exercise so as to maximize the bone development during adolescence and early adulthood.
Osteoporosis in and of itself is not a painful condition. Patients diagnosed with osteoporosis who do not have a fracture will not have pain related to osteoporosis. However, patients with an osteoporotic compression fracture will generally have localized back pain, and may also have some radicular leg pain due to adjacent nerve irritation. Because osteoporosis and arthritis are both so prevalent in older adults, it is sometimes difficult to ascertain which condition may be causing pain. Patients with severe hip or leg pain may have a compression fracture with nerve compression, or the pain may be caused by n insufficiency fracture of the hip or leg. A patient may also have difficulty walking and standing because of the pain.
Patients often have localized tenderness over the fractured vertebrae. There may also be noticeable bruising or swelling if the fracture is recent, and a kyphotic (forward angulation) deformity may be present if the bone compression is severe. The neurologic examination is usually always normal.
X-rays are the most important imaging study to obtain when evaluating compression fractures. Anteroposterior (AP – x-ray is taken facing the patient directly) and lateral (x-ray is taken from the side view) x-rays should be taken with the patient standing in order to adequately evaluate a spinal fracture and deformity. Of note, osteoporosis cannot be seen on plain x-rays until there is nearly 30% loss of bone mass. Therefore, a DEXA scan is required for all patients to accurately evaluate bone mineral density. A bone scan may be helpful to determine if a fracture is acute (new) or old (chronic). A magnetic resonance imaging (MRI) test may also be indicated if there are leg pain (sciatica) symptoms, neurologic dysfunction, or suspicion for cancer.
Dual-energy x-ray absorptiometry (DEXA) is an x-ray based scanning procedure that is used to determine bone mineral density. The technique involves scanning the spine, wrist, and hip and takes approximately 15 minutes to perform, and is extremely accurate. In addition, DEXA utilizes an extremely low dose of radiation (1-3mrem), which is 1/20th of the amount of radiation used for a standard chest x-ray.
Blood tests such as a basic metabolic panel, chemistry, and CBC (complete blood count) should be obtained in any individual presenting with an osteoporotic compression fracture. Thyroid function tests should also be obtained in patients with known or suspected thyroid dysfunction. Serum (blood) and urine protein electrophoresis are tests that should be ordered when multiple myeloma or is suspected.
The diagnosis of osteoporosis and a compression fracture should be suspected in any patient with back pain over 50 years old, as well as anyone younger who has significant risk factor(s). An x-ray is required to confirm the presence of a fracture, and may also suggest osteoporosis. A DEXA scan is essential to determine the severity of bone mass loss, and can be used to track improvement in bone mass after treatment is initiated. Additional imaging such as bone scan, CT, and/or MRI may also be useful in various clinical scenarios to evaluate nerve compression or other pathologic entities. Laboratory tests are critical to evaluate for secondary causes of osteoporosis and pathologic conditions such as lymphoma, leukemia, and multiple myeloma.
One of the best treatments for osteoporosis is prevention. Therefore, specific guidelines have been issued regarding the recommended intake of Calcium and Vitamin D by the National Research Council.
Recommended Daily Intake
In addition to adequate nutrient intake, a regular weight-bearing exercise program is recommended for people throughout life to help prevent osteoporosis and maintain bone stock. For postmenopausal women, hormone replacement therapy is highly recommended except in women with a strong family history of breast cancer or a personal history of blood clots or stroke. Hormone replacement therapy has been shown to decrease the incidence of vertebral fractures by 50%, as well as diminish the mortality rate due to cardiovascular disease. In addition to many regular estrogens and estrogen/progesterone combinations available, raloxifene is a selective estrogen-receptor modulator that is FDA-approved for prevention of bone loss in menopausal women. Anti-resorptive agents, such as bisphosphonates and calcitonin, are medications that reduce bone loss and often help restore bone mass. Alendronate and risedronate are two oral bisphosphonates that are FDA-approved for use in the treatment of osteporosis. In one study, alendronate was shown to increase bone density by 5% after one year.
|AGE RANGE||CALCIUM (MG/DAY)||VITAMIN D (IU)|
The primary side effects include dyspepsia and gastric upset. Calcitonin is FDA-approved for osteoporosis and can be administered by injection, using a nasal spray, or by rectal suppository. It can become antigenic and develop resistance, but is noted to be effective and demonstrated a 35-75% decrease in the rate of vertebral compression fractures in recent studies. Of note, calcitonin is also known for its analgesic (pain reducing) effects and can significantly decrease the pain associated with osteoporotic fractures and stress fractures.
A patient who has recently developed an osteoporotic spinal compression fracture will generally be recommended for a Jewitt-style back brace and be issued pain medications. Patients will also be evaluated by an x-ray and DEXA scan, and consideration for treatment with anti-resorptive agents will be considered. Females will be considered for hormone replacement therapy.
Patients with osteoporotic compression fractures who fail to improve with conservative treatments will be considered for surgery. Kyphoplasty and vertebroplasty are relatively new techniques that allow a compression fracture to be stabilized with bone cement (polymethylmethacrylate, or PMMA). The procedure is minimally-invasive and the cement is injected into the fractured bone through a percutaneous (poke hole through the skin) incision. Patients generally have rapid improvement of pain and the rate of complication is very low.
Barzel US: Estrogens in the prevention and treatment of postmenopausal osteoporosis: a review. Am J Med 1988;85:847.
Belkoff SM, Mathis JM, Fenton DC, et al: An ex vivo biomechanical evaluation of an inflatable bone tamp used in the treatment of compression fracture. Spine 2001;26(2):151.
Belkoff SM, Mathis JM, Jasper LE: The biomechanics of vertebroplasty the effect of cement volume on mechanical behavior. Spine 2001;26(14):1537.
Deramond H, Depriester C, Galibert P, Le Gars D: Percutaneous vertebroplasty with polymethylmethacrylate. technique, indications, and results. Radiol Clin North Am 1998;36(3):533.
Harris ST, Watts NB, Genant HK, et al: Effects of risedronate treatment on vertebral and nonvertebral fractures in women with postmenopausal osteoporosis: a randomized controlled trial. JAMA 1999;282:1344.
Johnston CC, Slemenda CW, Melton LJ: Clinical use of bone densitometry. N Engl J Med 1991;324:1105.
Lane JM, Riley Eh, et al: Osteoporosis: diagnosis and treatment. J Bone Joint Surg Am 1996;78:618.
Liberman US, et al: Effect of oral alendronate on bone mineral density and the incidence of fractures in postmenopausal osteoporosis. N Engl J Med 1995;333:1437.
NIH Consensus Development Panel on Optimal Calcium Intake: Optimal calcium intake. JAMA 1994;272:1942.
Prince RL, Smith M, et al: Prevention of postmenopausal osteoporosis: a comparative study of exercise, calcium supplementation, and hormone-replacement therapy. N Engl J Med 1991;325:1189.
Riggs BL, Melton LJ: The prevention and treatment of osteoporosis. N Engl J Med 1992;327:620.
Tilyard MW, Spears GF, et al: Treatment of postmenopausal osteoporosis with calcitriol or calcium. N Engl J Med 1992;326:357.
Tohmeh AG, Mathis JM, Fenton DC: Biomechanical efficacy of unipedicular versus bipedicular vertebroplasty for the management of osteoporotic compression fractures. Spine 1999;24(17):1772.
Weill A, Chiras J, Simon JM, et al: Spinal metastases: indications for and results of percutaneous injection of acrylic surgical cement. Radiology 1996;199(1):241.