Increasing human longevity is complicated by aging related physiological deteriorations. Osteoporosis, weakening of the skeletal bony units, is one of the major concerns which has developed into a major public health problem.1 According to the World Health Organization, osteoporosis affects approximately 75 million people in Europe, USA, and Japan. Although data are not available in China, with her large population, a vast number of people would be expected to be affected.2
The aging individual might not be aware of osteoporosis until fracture complications occur. When the apparently normal aging process abruptly turns into a disastrous mishap with the occurrence of fracture, the orthopaedic surgeon becomes directly involved. The rising incidence of hip fractures is often related to osteoporosis. A large number of patients with low back pain among the elderlies is caused by or related to osteoporotic compression of the vertebral bodies.3,4
TREATMENT OF OSTEOPOROSIS
The last 40 years have demonstrated a show of the strength of pharmaceutical departments in their successful attempts to search for potent anti-osteoporotic agents. Starting with hormonal replacement therapy in the 1960's, to oestrogenreceptor mediators (SERMS), and osteoclast suppression therapy and promotion of osteoblast activity, more and more potent therapies for the maintenance of bone density have become available (Figure 1).5
The forty years of therapeutic practice for the treatment of osteoporosis has matured to clearly define guidelines for clinicians, including orthopedic surgeons. The diagram that follows gives a logical recommendation for osteoporosis therapy in the last century (Figure 1).
In 1995 the Federal Drug Administration (FDA) recommended alendronate as the first anti-osteoporosis medication for post menopausal osteoporosis. This member of a group of drugs known as bisphosphonates suppresses the activities of the osteoclasts which initiate bone resorption, thus indirectly protects the bone structure. Since then more potent bisphosphonates have been produced in the laboratory, requiring less frequent administration. Zoledronic acid is the latest product which, when given intravenously, has a prolonged effect of one year.6 The use of bisphosphonates for the treatment as well as prevention of osteoporosis has been a routine practice in the past decade, irrespective of the severity of the actual decline in bone density, until unexpected observations, which will be discussed in a subsequent paragraph, started to be reported.
HOW DOES OSTEOPOROSIS AFFECT QUALITY OF LIFE OF PATIENTS
A review of the studies done on the quality of life (QoL) in relation to osteoporosis have clearly shown that when fracture occurs in an osteoporotic person, the deteriorations in the physical components of QoL are obvious. When no fracture complication is associated, special co-existing factors would contribute towards the changes in QoL.7 The contributing factors include history of fracture, loss of height and presence of spinal deformities, all of which are apparently, directly or indirectly, related to fractures. For the osteoporosis without fracture, there is no evidence of QoL changes.
With the clear indications that osteoporotic fractures would lead to a serious decline of the QoL, analyzing the factors that would help with the prevention of fractures would be of real value. In other words, the determinants leading to fracture would need to be analyzed.
Adachi in Canada, after studying 1129 post-menopausal women with a mean age of 67 years (SD 11.9 years), extensively discussed the determinants related to fractures and poor QoL. Regular exercise and higher educational levels are supportive of the maintenance of QoL. Adverse factors include a family history of falls, fractures and surgery, smoking, and cardiovascular problems. A variety of medications also negatively affect osteoporotic fractures.8
Low back pain by itself is the most common musculoskeletal complaint among all ages, so that para-menopausal women might not consider it significant unless they experience sudden exacerbation which might indicate a fresh vertebral fracture. In fact, it needs to be stressed that deteriorating bone density initiates microfractures and slow but gradual collapse of the vertebral bodies are responsible for more obvious affections of back pain.9 Timely intervention in such situations could be useful for prevention of sudden deteriorations.
One classical presentation of osteoporotic vertebral collapse is the sudden massive collapse of one vertebral body. The acute onset of disabling back pain results in immediate hospitalization and confinement to bed for days, if not weeks. The attending clinicians will face an immediate dilemma: mobilization is essential for prevention of pneumonia and yet only bed rest would secure a pain free rescue.
HOW DOES OSTEOPOROSIS AFFECT SURGICAL PLANNING
When fracture occurs as a result of bone fragility associated with minor twists and low energy falls, the balance between functional demand and practicality becomes important. Irrespective of age and related problems, functional restoration is always a priority. Yet, the fragmentation and comminution often accompanying osteoporosis could be a serious obstacle to methods of fixation and immobilization. For those elderlies who are otherwise healthy and have high functional demands, special devices and implants could be used.10 Special techniques like the use of bone cement to help holding the reduction of implants, could be another consideration in difficult operative endeavors.11
Another area of osteoporotic fracture that often deserves the surgeons' special attention is the spine. When osteoporotic collapse occurs, surgeons tend to be either conservative, not trying hard enough for pain relief, or over-reactive, advising on the use of surgical means to treat the collapse. In the former case, it might be fair to assure the patient that pain will ease out when the fresh collapse becomes stable and the inflammatory reactions subsides. The use of anti-inflammations agents and parathormone inhalation or injection could be very useful.12 In the latter case, it must be pointed out that unless the osteoporotic vertebral compression fracture happens in a younger patient, and the involved vertebral body is undoubtedly solid, the functional expectations from either vertebroplasty or augmentation (kyphoplasty) have not been proven in the past.13,14 Unnecessary surgical attempts should therefore be cautioned.
WHAT IS THE CURRENT SITUATION OF THE THERAPEUTIC TREATMENT FOR OSTEOPOROSIS?
Although almost all world authorities and treatment guidelines are recommending bisphosphonates as the first line medication for post menopausal osteoporosis, the risks of long term consumption are gradually being revealed. While upper gastro-intestinal irritations like heartburns, oesophagitis, and gastritis could be relatively harmless, serious complications arising from prolonged consumption have repeatedly appeared. The most serious variety is osteonecrosis of the jaw, often related to high doses of potent bisphosphonate used in cancer cases. When appearing in osteoporosis patients, the incidence is estimated to be around one in 10 000 and the concomitant use of steroids, smoking, diabetes and poor oral hygiene could be predisposing factors. Over-suppression of bone resorption and bone turn-over and impairment of auto healing of microfractures could be the underlying mechanisms of atypical femur fractures which are repeatedly encountered among patients after treating with bisphosphonates for over 5 years.
After many decades of bisphosphonates, the recommendations have been rightly compromised. The American Society of Bone Mineral Research Task Force Report has made this statement: “Decision on long-term bisphosphonate treatment should be individualized. It may be beneficial for some women, particularly those at high vertebral fracture risks”.15
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