After hip resurfacing, bone mineral density continued to positively change up to 5 years, primarily in the trochanteric and superior neck regions, according to recent study results published in the Journal of Arthroplasty.
“This study demonstrates that femoral component size has a significant role to play in the change in [bone mineral density] BMD up to 5 years,” the researchers wrote in their study.
The researchers noted that the larger the femoral component, the greater the mean decrease in BMD in the trochanteric area at 6 weeks and superior neck region at 5 years.
“The greater the acetabular inclination, the greater the increase in trochanteric area BMD at 5 years,” the authors wrote. “A valgus position of the femoral component leads to a significantly greater increase in the BMD both in the superior femoral neck region and trochanteric area at 5 years.”
Researchers prospectively studied BMD change in 31 patients with a Birmingham Hip Resurfacing (Smith & Nephew; Memphis, Tenn.) system. At 5-year follow-up, data were available for 26 patients.
BMD had decreased by up to 10% in the trochanteric and superior neck regions at 6 weeks and 3 months after surgery before recovering to preoperative levels by 1 year. According to regression analysis assessing the influence of age, gender, BMI, preoperative BMD, component size and orientation, acetabular component inclination was the best predictor of change in BMD at 5 years in the trochanteric area.
Disclosure: The researchers reported receiving support and payment from Amgen and P+G Pharmaceuticals, Freeman Hospital – Stryker and Zimmer.