Determining appropriate candidates for hip preservation surgery is challenging because criteria for judging appropriateness are not defined. The American Academy of Orthopaedic Surgeons (AAOS) recently published a hip preservation surgery appropriateness classification system using the RAND/University of California, Los Angeles approach. This study was undertaken to determin the extent and pattern of contribution of each of the variables used to predict the appropriateness of hip preservation surgery.
An AAOS-appointed multidisciplinary expert panel wrote 270 clinical vignettes incorporating all permutations of 5 indication variables derived from an evidence synthesis. A second independent panel of experts rated the appropriateness of each vignette during multiple Delphi surveys. We used logistic regression to determine the relative contribution of each variable to classification. We also used a classification-tree approach to determine which indication variables, in combination, contributed to the final classification.
Odds ratios from the regression indicated that patient age and radiographic hip osteoarthritis (OA) evaluation were the main indications of appropriateness classification (e.g., the odds ratio for age <40 years was >999.99, with age >65 years as the referent group, for "appropriate/may be appropriate" as compared to "rarely appropriate" vignettes). Hip range of motion, risk for negative outcome, and function-limiting pain did not meaningfully contribute to the final classification.
The AAOS appropriateness classification system for hip preservation surgery is driven almost exclusively by age and radiographic hip OA evaluation. Additional research on appropriateness classification for hip preservation surgery is needed to identify important indication variables beyond age and radiographic hip findings.