Treating osteoporosis in an orthopedic practice is challenging. Orthopedic clinicians are typically not as well-versed in osteoporosis diagnosis and treatment as they may be with other musculoskeletal conditions. Many times, the orthopedic provider feels that this should be managed by the patient’s internist or primary care physician. However, it has been shown that providing osteoporosis care in orthopedic settings can have significant positive effects on prevention and treatment of osteoporotic fractures. Additionally, most patients who are identified with an osteoporotic fracture and subsequently treated surgically for that osteoporotic fracture is not treated for their underlying osteoporosis.
Patients are also reluctant to be treated with medications for their osteoporosis. They are concerned about side effects they may have heard on television or read in newspapers. They also may feel like that they are too old for treatment and just want to treat their osteoporosis “naturally.”
If this is the case, then what is the physician assistant in orthopedics to do when encountering a patient with osteoporosis or who has just suffered an osteoporotic fracture?
All orthopedic providers are aware of the effects of osteoporosis on bone. We commonly see the fractures and the subsequent morbidity and mortality of such fractures. However, many times we are not comfortable with the medical management with pharmaceutical agents for osteoporosis. This blog is not meant to educate clinicians on the proper use of these drugs nor is it to serve as medical advice for treatment of osteoporosis with drug therapy. However, I do recommend increasing your knowledge of the most commonly used anti-resorptive and anabolic medications. The National Osteoporosis Foundation (NOF) has abundant literature for the clinician interested in treating osteoporosis with pharmacotherapy. Osteoporosis experts, whom I have learned from, recommend becoming familiar with the mechanism of action, dosage and side-effect profile of a handful of medications as a starting point. Also, there are guidelines set forth by the American Academy of Clinical Endocrinology that can serve as an initial basis for treatment. According to the 2016 ACE/AACE Guidelines for treatment of osteoporosis in post-menopausal women who have already suffered a fracture, the first-line treatment includes zoledronic acid, denosumab and teriparatide.
Zoledronic acid is a bisphosphonate medication given as a once-yearly IV infusion. It is an anti-resorptive agent that focuses on suppression of osteoclast activity. It has been shown to reduce vertebral fracture risk by 70%, hip fractures by 41% and nonvertebral fractures by 25%. It is contraindicated in patients with a GFR of less than 35, and creatinine clearance should be monitored prior to each dose of zoledronic acid. Rash, eye inflammation and acute phase reaction are all common side effects.
Denosumab is a human monoclonal antibody to RANK-ligand. It is, also, considered an anti-resorptive agent. It has been shown to reduce risk of vertebral fractures by 68%, hip fractures by about 40% and non-vertebral fractures by about 20% over 3 years. It is given as a twice-yearly injection, and its common side effects include hypocalcemia, skin rash, cellulitis and an acute phase reaction.
One cannot discuss anti-resorptive agents without mentioning the potential side effects of osteonecrosis of the jaw (ONJ) and atypical femur fractures (AFF). Both are exceedingly rare and can be seen in patients who have never taken an anti-resorptive drug. Incidence of ONJ is between 1/10,000 to 1/100,000 patient years and is associated with high-dose bisphosphonate treatment for cancer, patients with diabetes mellitus and in those with poor oral hygiene. Atypical femur fractures are seen in one in 10,000 patients after 1 year of bisphosphonate treatment and one in 1,000 patients after 10 years of treatment, according to the Kaiser Permanente data registry. These may be bilateral, a prodrome of thigh or groin pain is seen in 70% of patients and are seen more frequently after more than 5 years of treatment.
Teriparatide, or PTH (1-34), is an anabolic agent that works via increasing osteoblast activity. It reduces risk of vertebral fractures by about 65% and non-vertebral fractures by about 53% in patients with osteoporosis after an average of 18 months of therapy. It is given as a once-daily subcutaneous injection. Bone loss can be rapid when it is stopped, so alternative agent should be considered to maintain BMD. Treatment is not to exceed 18 to 24 months. Common side effects include leg cramps, nausea and dizziness. It is contraindicated in Paget’s disease, prior radiation to bone or history of bone metastases. There is also a black box warning of a risk of osteosarcoma.
If you are not comfortable with thought of osteoporosis medications, I recommend prompt referral to your closest fracture liaison service, endocrinologist, nephrologist or primary care physician well-versed in these drugs and comfortable in their prescription.