A novel therapy-oriented acetabular defects classification based on quantitative assessment statistical shape models

Background: The purposes of this study was to develop a novel therapy‑oriented acetabular bone defects classification system based on Statistical shape models (SSMs) and evaluate the reliability and reproducibility of its application. Methods: : We retrospectively reviewed and annotated pelvic Computed tomography (CT) of patients who had undergone revision total hip arthroplasty at our institution and constructed a dataset to develop the novel method for quantitatively describing acetabular bone defects that is based on SSMs. Then, using this method, classification systems are suggestive for diagnosis and corresponding treatment suggestion. In addition, the interobserver and intraobserver reliability of this classification system compared to the Paprosky classification system was calculated. Results: : The novel classification based on SSMs was successfully applied to 106 hips, Incidences of type A, B, C, D and E were 25.5%, 41.5%, 13.2%, 14.2% and 5.7%, respectively. Compared to the Paprosky classification, the novel classification system demonstrated a higher level of interobserver and intraobserver reliability for diagnosis (0.828 and 0.844) and treatment suggestions (0.828 and 0.844). Conclusion: This classification system, which has demonstrated moderate to strong interobserver and intraobserver reliability, may be particularly useful to accurately evaluate acetabular defects and suggest surgical strategies, as a complement to the traditional Paprosky classification system in revision THA.