Value of scintigraphy in aseptic loosening of cemented and cement-free hip endoprostheses

Abstract

Scintigraphic findings in 24 cemented and 25 cement-free prostheses were compared to determine the information value of scintigraphy in the diagnosis of loosening of total hip replacements. The scintigraphic findings were evaluated on the basis of specificity (indicates the percentage of complaint-free hips in which the scan is also negative) and sensitivity (indicates the percentage of clinically loosened hips in which the scan is also positive) in relation to the clinical diagnosis. For the cemented prostheses, the specificity value was 58% and the sensitivity 66%. The figures for the cemented prostheses were 15% and 83% respectively. On the basis of the authors' results it may be inferred that for cemented hip replacements the scan represents a valuable supplement to clinical and radiologic diagnosis. For the cement-free type of prostheses used by the authors, neither the scan nor radiology are suitable for diagnosing loosening; with these prostheses the findings obtained by clinical examination are the most reliable.