Aim of this study is to proof the efficacy of in Jena established prophylaxis of new bone formation aside the skeleton with irradiation and compare it with the common literature. Furthermore we want to compare irradiation treatment with the alternative prophylaxis with analgetics from the NSAID type.

Aim of this retrospective analysis is to compare the incidence of heterotopic ossification one year after total hip arthroplasty with the at our location established concept of irradiation 24h preoperative and incidence in common literature. Furthermore the comparison between irradiated patients and patients treated with NSAIDs.

Inclusion Criteria:

Patients with total hip arthroplasty performed at Eisenberg Patients with preoperative irradiation (24h pre-op) or postoperative diclofenac treatment Patients with x-ray images immediately (3-5 days postoperative) postoperative and at least 365 days postoperative

Exclusion Criteria:

Patients with missing follow up image

All participants of the study are patients at the Universitätsklinikum Jena or the Waldkrankenhaus Eisenberg. Irradiation was performed in Jena. Total hip arthoplasty and following inpatient stay, inclusive NSAID therapy was performed in Eisenberg