Sarcopenia in Orthopedic Surgery.

Sarcopenia is a loss of skeletal muscle mass in the elderly that is an independent risk factor for falls, disability, postoperative complications, and mortality. Although its cause is not completely understood, sarcopenia generally results from a complex bone-muscle interaction in the setting of chronic disease and aging. Sarcopenia cannot be diagnosed by muscle mass alone. Diagnosis requires 2 of the following 3 criteria: low skeletal muscle mass, inadequate muscle strength, and inadequate physical performance. Forty-four percent of elderly patients undergoing orthopedic surgery and 24% of all patients 65 to 70 years old are sarcopenic. Although dual-energy x-ray absorptiometry and bioelectrical impedance analysis may be used to measure sarcopenia and are relatively inexpensive and accessible, they are generally considered less specific for sarcopenia compared with computed tomography and magnetic resonance imaging. Sarcopenia has been shown to predict poor outcomes within the medical and surgical populations and has been directly correlated with increases in taxpayer costs. Strengthening therapy and nutritional supplementation have become the mainstays of sarcopenia treatment. Specifically, the American Medical Directors Association has released guidelines for nutritional supplementation. Although sarcopenia frequently occurs with osteoporosis, it is an independent predictor of fragility fractures. Initiatives to diagnose, treat, and prevent sarcopenia in orthopedic patients are needed. Further investigation must also explore sarcopenia as a predictor of surgical outcomes in orthopedic patients.