Are morbidly obese patients undergoing total hip arthroplasty at an increased risk for component malpositioning?

Acetabular cup positioning is a critical factor in determining adverse clinical outcomes in THA. This evaluation was performed to determine if morbid obesity (BMI ≥35kg/m(2)) is a contributing risk factor to cup malpositioning. Two groups of patients were obtained from a local arthroplasty registry and match-controlled for gender, age, and diagnosis (n=211 morbidly obese; n=211 normal). Intraoperative data and postoperative AP pelvis and cross-table lateral radiographs were obtained for each patient. The Martell Hip Analysis Suite was used to calculate cup positioning (successful positioning defined as 30°-45° of abduction, and 5°-25° of anteversion), as well as varus-valgus alignment of the femoral stem. There was a significant correlation between morbid obesity with respect to underanteversion; using multivariate analysis, there was a trend toward a combined underanteversion/overabduction of the acetabular cup. Of all variables considered, high BMI was the most significant risk factor leading to malpositioning.

Nine-year incidence of kidney disease in patients who have had total hip arthroplasty.

Metal-metal total hip arthroplasty (THA) is contraindicated in patients with impaired renal function due to increased metal ion output relative to other bearings and renal excretion of metal ions. Although one can avoid a metal-metal THA in a patient with renal disease, a patient may be destined to develop renal disease later in life. In this study, we sought to determine the incidence of newly diagnosed renal disease in the 9 years after THA. Using the Department of Veterans Affairs national database, we identified 1709 patients who had a primary THA in 2000 without preexisting renal disease. We found the 9-year risk of developing chronic renal disease after primary THA to be 14% and severe or end-stage renal disease to be 6%.