Acetabular fracture occurring intraoperatively during hip arthroplasty but recognized only after surgery are classified as type IC by Della Valle.
They can be simple or complex. Cup may be stable or unstable.
Further information about Della Valle classification can be found in the publication: Della Valle CJ, Momberger NG, Paprosky WG. Periprosthetic fractures of the acetabulum associated with a total hip arthroplasty. Instr Course Lect. 2003;52:281–290.