Chapter 29 Osteoporosis (Including Kyphoplasty)
Anatomy Overview
• Two types of bone are found in the body: cortical and trabecular.
1 Cortical bone comprises 80% of the skeletal mass and is primarily responsible for skeletal strength. The cortical bone has a slow turnover rate and high resistance to bending and torsion.
• Bone remodeling is a continuous process of bone resorption and bone formation. Osteoporosis can result from an imbalance in the normal remodeling process.
• Skeletal factors, such as low bone density and impaired bone quality, as well as non-skeletal factors, including poor balance and falls, play an important role in the development of osteoporosis and osteoporotic fractures.
• Bone density is by far the best measure of fracture risk. It accounts for almost 70% of bone strength.
• Bone strength is affected by changes in bone quality (impaired mineralization, increased bone turnover, and diminished trabecular microarchitecture). Because trabecular bone has high metabolic activity, it is more affected by bone turnover, resulting in greater resorption, weakening the microstructure of the bone and increasing susceptibility to fracture.
Differential Diagnosis
• Primary osteoporosis is age-related.
1 It is largely caused by estrogen deficiency, which results in high turnover bone loss. subsequently, areas that are high in trabecular bone are more affected.
• Secondary osteoporosis is bone loss related to chronic disease, medication therapy, or lifestyle.
1 A wide variety of medical conditions have been linked to the development of osteoporosis, including rheumatoid arthritis, multiple myeloma, hyperparathyroidism, hyperthyroidism, inflammatory bowel disease, chronic kidney disease, and transplantation.
2 Oral glucocorticoids are by far the most common pharmaceutical associated with drug-induced osteoporosis; however, inhaled glucocorticoids, anticonvulsant medications, neuroleptic agents, methotrexate, and lithium have all been known to have detrimental effects on bone.
• The diagnosis of osteoporosis is made via both laboratory tests and physical exam.
1 Bone pain, kyphosis, loss of height, and x-ray findings are all factors that may lead to further testing to rule in or out the diagnosis of osteoporosis.
• Several technologies are available for measuring BMD; however, central dual-energy x-ray absorptiometry (DXA) is the gold standard.
• Generally, the hip is the preferred site of BMD measurement and has been shown to be the best predictor of fracture risk.
• Three key pieces of information are obtained from the bone densitometry report: actual BMD, T score, and Z score.
2 The T score is a comparison of the patient’s measured BMD with the mean BMD of a healthy, young (25- to 30-year-old) sex matched reference population. The purpose of using a young, matched population is to compare the BMD with that of a population at peak bone mass. This number is reported as the number of standard deviations from the mean.
Rehabilitation Overview
• The evaluation of the osteoporotic patient should be comprehensive and include a detailed history, including prior history of fractures and falls, BMD scores, as well as any of the other risk factors that may contribute to the diagnosis of osteoporosis (Box 29-1). It is also important to obtain a detailed exercise history, paying special attention to the amount of weight-bearing activity that the patient participates in on a daily basis.
• The objective examination should include five major areas of assessment: patient posture and body mechanics, flexibility, strength, balance, and weight-bearing (Box 29-2). Addressing these five key areas during the evaluation and then subsequent rehabilitation is the basis of the five-point program for osteoporosis at HSS.
1 The severity of thoracic kyphosis has been associated with the occurrence of vertebral fractures, most likely as a result of the loss of vertebral height. A measurement of the thoracic kyphosis can be taken with a FlexiCurve ruler and documented.
2 The measurement of strength and flexibility is fairly straightforward in this population; however, special attention should be paid to back extensor strength, in particular. Back extensor strength has been shown to be inversely proportional to both kyphosis and vertebral fracture.
3 Strength measurements of hip extensors, scapular, and lower abdominal stabilizers are also important.
4 Flexibility of the anterior chest musculature, hip flexors, and ankle plantar flexors is required to allow for correct posture and body mechanics and should be evaluated.
5 The assessment of balance is crucial because falls prevention in this population is a primary goal. Unilateral stance time with eyes opened and closed, functional reach, and “timed get-up and go test” are the tools used at HSS to measure balance, because the results can easily be correlated to falls risk.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
