PAST LETTERS FROM THE PRESIDENT
Michael
A. Mont, M.D.; Phillip S. Ragland, M.D.; Khaled J. Saleh, M.D.;
Lynne C. Jones, Ph.D.; and David S. Hungerford, M.D.
Introduction: Multiple classification systems for avascular
necrosis of the hip have been developed to assist physicians in the diagnosis
and treatment of this potentially debilitating disorder. However, this
lack of consistency makes clinical decision making difficult when comparing
publications. The purpose of this study was to quantify the classification
systems reported since 1985 (post-MRI) and identify consistent factors
which would allow cross-publication comparisons to be made.
Methods: The authors performed a PubMed search for reports of outcome studies concerning treatment methods of hip avascular necrosis that were the initial basis for analysis. All studies reported since 1985 were included in the analysis if outcomes of greater than 10 patients treated for this disease were reported. Classification systems utilizing at least one factor were also identified. Tabulation of how frequently these classification systems were used in terms of the number of studies reporting results was performed.
Results: Fifteen major classification systems utilizing more than one radiographic factor were identified with 9 having one to three modifications reported throughout the literature. Additionally, 14 systems utilized either MRI or anatomic factors. Cross-publication analysis revealed four major classification systems which were utilized in greater than 80% of the reported studies.
Discussion: This analysis of the reported classification systems for avascular necrosis of the femoral head revealed several similarities between systems. A cross system analysis can be made if data is collected according to patient symptoms, magnetic resonance imaging findings, and x-ray findings which would allow for the use of any staging system.