Fit and fill total hip arthroplasty: Is it still efficacious?

Purpose of review: The purpose of this review is to examine the 'fit and fill' principle using specific reference to a particular stem design, anatomic porous replacement, with which the senior surgeon has had extensive clinical experience. Recent findings: Cementless fixation on the femoral side in total hip arthroplasty has become increasingly popular. This increase in clinical usage of cementless femoral stems is based upon many factors including improvements in implant design, surgical technique, and confirmation of excellent clinical outcome and durability. One of the earliest design rationales in the evolution of cementless femoral stems was the concept of 'fit and fill'. This premise was based upon the belief that maximizing contact of the stem with host bone would provide the greatest fixation stability and the most optimal long-term bone remodeling of the upper femur. The long term (10 years) survivorship of anatomic porous replacement II stems which is based on this concept has been validated by recent studies. Summary: Many cementless stem design concepts have been put into clinical application over the past three decades. One of the most original, and durable concept has been the 'fit and fill' principle. This concept has been validated to be valuable in providing longterm, pain-free, stable total hip arthroplasty function. With the advent of newer prosthetic designs and improved surgical techniques, the use of cementless stems is promising and should continue to be considered in younger and more active patients with good bone quality.