PTH and osteoporosis: Although we did not observe relationships between the presence of osteoporosis or other indicators of poor bony health (DEXA score, vitamin D, PTH levels) and risk of failure in our cohort, recent evidence supports the notion that the presence of osteoporosis, or the observation of lower Hounsfield Units as measured by computed tomography at the UIV, can provide important prognostic information on risk for failure.23, 24, 25