R DeMasi

University of North Carolina at Chapel Hill, Chapel Hill, NC, United States

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Publications (3)7.01 Total impact

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    ABSTRACT: The authors studied the clinical and radiographic results of a modern titanium-alloy femoral stem with a cobalt-chrome-alloy head for use in cemented total hip arthroplasty. One hundred sixteen hips (102 patients) were operated on using modern cement techniques and prospectively followed using the Hospital for Special Surgery hip rating system and standard radiographic criteria. At a mean follow-up period of 4.8 years (range, 2-8 years), 69 hips were rated excellent, 38 good, 4 fair, and 5 poor. A total of 13 femoral components (11%) were radiographically loose according to the criteria of Harris. In 11 of these loose femoral components, debonding or separation at the cement-prosthesis interface, was the initial cause of failure, with bone-cement interface erosions occurring later in five hips. Revision of a loose femoral component has been performed in three hips and is pending in two other hips (4.3%). Significant calcar resorption was seen in only 17 hips (14.6%), and serial measurements of distal femoral cortical widths showed no distal cortical hypertrophy except in one femur. The incidence of loosening with this cemented titanium-alloy femoral component (with a cobalt-chrome-alloy head) is much higher than published reports of similar cobalt-chrome-alloy stems. The authors have abandoned the use of titanium-alloy femoral components for cemented total hip arthroplasty.
    The Journal of Arthroplasty 01/1995; 9(6):623-30. · 2.11 Impact Factor
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    ABSTRACT: Ninety-four high-modulus total hip arthroplasties (THAs) were performed from 1977 to 1982 using the Computer Assist Design (CAD) and HD-2 prostheses. Eighty-six hips were followed for an average of 6.7 years. The cement gun was used throughout the study period, and distal bone or cement plug use was begun in 1979. The results of these arthroplasties were evaluated retrospectively using both survivorship analysis and observed success rates. Using a standard hip rating system, 19 hips were rated as excellent, 44 as good, 15 as fair, and 11 as poor. Failure was defined as definitely visible radiographic migration of either component, or reoperation for revision of one or both components. There was no significant difference between the HD-2 and CAD prostheses. There were five hips revised for aseptic loosening and revision was advised in an additional three hips. One hip with late sepsis required removal of both components. The five- and ten-year survivorships of the acetabular components were 97% +/- 3 and 58% +/- 17, respectively. Those of the femoral components were 93% +/- 5 and 78% +/- 13, respectively. For the components combined, the survivorship at five years was 91% +/- 6 but only 50% +/- 17 at ten years. Survivorship analysis provided a different and more realistic appraisal of the long-term results of the arthroplasties in this series than did the observed success rates. The contemporary cement techniques of the late 1970s and early 1980s may not be sufficient for the long-term survival of high-modulus THAs. Additional techniques may be necessary for improved long-term survival.
    Clinical Orthopaedics and Related Research 10/1993; · 2.79 Impact Factor
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    ABSTRACT: This is a prospective study of the authors' first 100 Harris-Galante porous total hip arthroplasties (THA) that were followed for 2-5 years. The mean age of the 83 patients was 43 years. Using the Harris hip rating system, 80% of the hips were rated as excellent, 13% as good, 5% as fair, and 2% as poor at final evaluation. Eighty percent of the hips had no pain, 11% had slight or occasional pain, 8% had activity-related pain, and 1% had moderate pain. Eighty-seven percent of the hips had no limp, 8% had a slight limp, and 5% had a moderate limp. One femoral component, placed as a conversion of a loose bipolar hemiarthroplasty, has been removed for loosening. Two other hips have been reoperated, one for lengthening the femoral neck and one for changing the acetabular liner. There were no problems with acetabular screw fixation and no component migrated. Only two hips had 1 mm nonprogressive radiolucent lines in all three zones. Femoral component subsidence of 3 or more mm was measured in 16 hips, but was progressive in only 1. Radiolucent and radiodense lines were frequently seen in the nonporous coated regions of the femoral stem. Loss of proximal medial femoral bone density was seen in 59% of hips, and calcar resorption was seen in 16% of hips. Although the clinical results of this uncemented implant system were good or excellent in 93% of hips, the high incidence of femoral component subsidence is worrisome.
    The Journal of Arthroplasty 01/1993; 7(4):519-26. · 2.11 Impact Factor