Osteoporosis
A disease that weakens bones, making them fragile and more likely to break easily from a minor fall or normal daily activities.
Emergency Management: Hip fractures are surgical emergencies requiring operative fixation typically within 24-48 hours to minimize morbidity and mortality.
Osteoporosis is a systemic skeletal disease characterized by low bone mineral density (BMD) and microarchitectural deterioration of bone tissue. This leads to bone fragility and a significantly increased susceptibility to low-trauma fractures, most commonly in the spine, hip, and wrist.
Detailed Overview
Bone remodeling is a continuous process of resorption by osteoclasts and formation by osteoblasts. Osteoporosis occurs when bone resorption outpaces formation. It is clinically silent until a fracture occurs. Hip fractures carry a 1-year mortality rate of up to 20% in the elderly, making osteoporosis a major public health issue.
Epidemiology & Demographics
Affects roughly 10 million Americans, with another 44 million having low bone mass (osteopenia). Most common in postmenopausal women of Caucasian and Asian descent. 1 in 3 women and 1 in 5 men over age 50 will experience an osteoporotic fracture.
Etiological Mechanism
Primary osteoporosis is due to age-related bone loss and estrogen deficiency post-menopause. Secondary osteoporosis is caused by medications or medical conditions.
Primary Causes
Estrogen deficiency removes the inhibition on osteoclast activity. Secondary causes include chronic glucocorticoid use, hyperthyroidism, hyperparathyroidism, hypogonadism, and malabsorption syndromes (celiac).
Estrogen normally stimulates osteoprotegerin (OPG) production by osteoblasts. OPG acts as a decoy receptor for RANKL, preventing it from binding to RANK on osteoclasts. Post-menopause, reduced estrogen leads to lower OPG and higher RANKL expression. This drives excessive osteoclast proliferation, differentiation, and survival. The osteoclasts rapidly resorb trabecular bone, thinning the trabeculae and severing their connections, irreversibly compromising the structural integrity of the bone.
Diagnostic Criteria & Guidelines
Diagnosis is established by: 1) T-score <= -2.5 at the lumbar spine, total hip, or femoral neck by DEXA scan, OR 2) History of low-trauma fracture of the hip or spine, OR 3) T-score between -1.0 and -2.5 with a high FRAX score (10-year probability of major osteoporotic fracture >= 20% or hip fracture >= 3%).
Antiresorptive therapy: Oral Bisphosphonates (Alendronate 70 mg PO weekly or Risedronate 35 mg PO weekly). Ensure adequate Calcium (1200 mg/day total from diet + supplements) and Vitamin D (800-1000 IU/day) intake.
Second-Line & Adjunctive Therapy
IV Bisphosphonates (Zoledronic acid 5 mg IV yearly) for oral intolerance. RANKL inhibitor (Denosumab 60 mg SQ every 6 months) for high fracture risk. Anabolic agents (Teriparatide 20 mcg SQ daily or Romosozumab) for very severe osteoporosis (T-score < -3.0 or multiple fractures).
Surgical & Procedural Management
Surgical fixation (ORIF or arthroplasty) for hip fractures. Kyphoplasty or vertebroplasty for acute, painful vertebral compression fractures refractory to medical therapy.
Patient Counseling & Advice
Instructions for oral bisphosphonates: Must take first thing in the morning on an empty stomach with a full glass of plain water, and remain completely upright for 30 minutes to prevent erosive esophagitis and ensure absorption. Warn of rare risks like osteonecrosis of the jaw (ONJ) and atypical femur fractures with long-term use.
Follow-Up & Monitoring Schedule
Repeat DEXA scan every 1 to 2 years to monitor treatment response. Consider a 'drug holiday' after 3-5 years of bisphosphonate therapy if fracture risk has decreased.
Preventive Strategies
Maximizing peak bone mass in youth through adequate nutrition and exercise. Routine DEXA screening for all women >= 65 years and men >= 70 years.
Treatment effectively stops bone density decline and significantly reduces fracture risk by 30-50%. Pre-existing fractures cannot be reversed.