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S A Yoder

Publications and source records attributed to S A Yoder.

4 recordsLinked to original sources
PubMed1988

Total hip acetabular component position affects component loosening rates.

Loosening is the most common long-term problem following total hip arthroplasty. Many factors, including patient selection, cement technique, femoral component placement, and prosthesis design reportedly affect the incidence of loosening. Theoretically, the location of the hip center of rotation substantially affects the load on the hip, and superior and lateral hip center location will result in higher loads than medial and inferior placement. Long-term follow-up studies (average, 9.1 years after surgery) using logistical regression analysis demonstrate significantly higher rates of femoral loosening with acetabular components placed in a superior and lateral (i.e., nonanatomic) position, compared with acetabular components placed in a nearly anatomic position.

Acetabulum↗
PubMed1986

How definition of "loosening" affects the incidence of loose total hip reconstructions.

Loosening is the most common long-term problem following total hip reconstruction. For many reasons, it is important to identify the loosened total hip reconstruction. For some purposes, radiographic interpretation is the sole or principal determinant in loosening. However, there are inherent problems with such interpretations, and these problems have neither been explored in any detail in the literature nor emphasized. This article is a review of the literature and one of the problems of defining loosening. Interpretations of radiographic criteria of loosening are matters of judgment, but this judgment is not reflected in the descriptions of precisely how radiographs were interpreted. Definitions in the literature, based on lucencies and position changes, influenced the loosening rate by a factor of at least two, and influenced the apparent importance of risk factors affecting the long-term results by as much as two to three times. Thus by merely altering a definition one can alter which factors seem more or less important. The selection of a definition of loosening must be designed to a specific purpose, but data and a rationale should be provided as a basis for its interpretation. In general, descriptions of radiograph interpretation need to be precise and less subjective.

Adult↗
PubMedDate not supplied

Interobserver variability in interpreting radiographic lucencies about total hip reconstructions.

Radiographs are commonly used to identify the loosened total hip reconstruction (THR), to plan revision surgery, and to evaluate long-term follow-up patients for study purposes. Interobserver variability was studied in an attempt to interpret 63 random follow-up films in a group of 93 patients eight to 12 years post-THR. Nine observations were made on the acetabular and femoral sides of the reconstructions on all films for a total of 567 observations. There was considerable disagreement in observations of the acetabular lucencies; a consensus of all three observers was obtained only 46% of the time. There was more uniform agreement among observers (87%) in analyzing the femoral side, although agreement was most frequent when there was no lucency. There was no difference in observer variables when greater lucencies were reported by one or more observers than when there were smaller lucencies. It was concluded that a single observer can reliably record a femoral observation of no lucency and, making allowances for the Mach effect, can reliably distinguish the presence or absence of a lucency. However, a single observer may not be able to make observations of acetabular lucencies with great reliability and, in contrast to femoral lucencies, a single observer may be less reliable in recording acetabular lucencies over 2 mm as compared with those under 2 mm.

Acetabulum↗