Abstract
A) Mastering the Art of Cemented Femoral Stem Fixation
Introduction: Fixation of cemented femoral stems is reproducible and provides excellent early recovery of hip function in patients 60–80 years old. The durability of fixation has been evaluated up to 20 years with 90% survivorship. The mode of failure of fixation of cemented total hip arthroplasty is multifactorial; however, good cementing techniques and reduction of polyethylene wear have been shown to reduce its incidence. The importance of surface roughness for durability of fixation is controversial. This presentation will describe my personal experience with the cemented femoral stem over 30 years with 3 designs and surface roughness (RA) ranging from 30–150 microinches.
Results: Since 1978, three series of cemented THA have been prospectively followed using periodic clinical and radiographic evaluations. All procedures were performed by the author using the posterior approach. Excellent results were noted and Kaplan-Meier survivorship ranged from 90% to 99.5% in the best case scenario at 10–20 year follow-up.
Conclusion: With a properly-designed femoral stem, good cement technique, proper cement mantle, and surface roughness of 30–40 microinches, the cemented femoral stem provides a durable hip replacement in patients 60 to 80 years of age with up to 95% survivorship at 10 to 20 years.
B) Cemented Primary Acetabulum
Introduction: I am going to present a technique of cementing an all-polyethylene socket, a brief review of our clinical experience, and all-polyethylene socket design features. Since 1991, we have been using direct compression molded polyethylene sockets. The minimum thickness of polyethylene is 8 mm. We keep the socket orientation at 45 degrees of lateral opening and 15 degrees of anteversion. The preparation of the socket involves multiple fixation holes with Midas Rex. The bone is cleaned with water lavage and heated cement.
Radiographic Features: The cement/bone interface has been classified into three types on radiographs. Type 1 has a perfect merge of the cement into the cancellous bone in all three zones. Type III interface shows radiolucency in one or more zones.
A commonly asked question is, “is this technique reproducible?” The answer is yes.
Our Data: We have looked at our all-polyethylene socket from 1992 to 1998 and the total number of hips are over 1,000, with a follow-up of 2–8 years. We have not revised a single socket for fixation failure.
Summary: A cemented socket is indicated in patients 60 years and older with a diagnosis of osteoarthritis. Relative contraindications are excessive bleeding, extensive cyst formation, weak cancellous bone such as in rheumatoid, JRA, DDH, and protrusion patients. Cemented THA in patients 60 years and older with DJD and molded all-polyethylene cup have provided the best results in terms of a high degree of reproducibility, high quality of function, and durability.
