Abstract
A) Mastering the Art of Cemented Femoral Stem Fixation
Abstract:
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 multi-factorial; 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 to 150µm.
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 and Kaplan-Meier survivorship ranged from 90% to 99.5% in the best case scenario were noted 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 60–80 years old with up to 95% survivorship at 10–20 year follow-up.
B) Cemented Primary Acetabulum
Introduction:
I am going to present a technique of cementing an all-poly socket, a brief review of our clinical experience, and all-poly socket design features. Since 1991, we have been using direct compression molded polyethylene sockets. The minimum thickness of poly is 8mm. 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. The cement is pressurised at a doughy state.
Radiographic Features: The cement/bone interface has been classified into three types of radiograph. 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-poly 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: The indication are 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 protrusio patients. Cemented THA in patients 60 years and older with DJD and molded all-poly cup have provided the best results in terms of a high degree of reproducibility, high quality of function, and durability.
