Statistical shape models quantify acetabular defects in hip revision surgery: implications for classification and surgical planning

Purpose

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 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 16.04%, 27.36%, 34.91%, 14.15% and 7.55%, respectively. The novel classification system demonstrated a higher level of interobserver and intraobserver reliability (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.