Peri-prosthetic fractures around tumor endoprostheses: a retrospective analysis of eighteen cases

Purpose Tumour hip and knee endoprostheses have become the mainstay for reconstruction of patients with bone tumours. Fixation into host bone has improved over time. However, some patients present with a peri-prosthetic fracture over follow-up. The objective of this study was to analyse the mode of presentation and survival of implant after a peri-prosthetic fracture around a tumour endoprosthesis. Methods Eighteen peri-prosthetic fractures (17 patients) were included. All patients were treated at a tertiary care center. There were 11 (65 %) women; the median age at the time of fracture was 38 years old. All implants were cemented and all knee endoprostheses were fixed-hinge. Twelve (67 %) fractures occurred after femoral resection and six (33 %) fractures after proximal tibial resection. Results There were three femoral neck fractures (UCS C), three femoral shaft type C fractures, two femoral shaft type B1, one tibial shaft type B2, three tibial shaft type C, three ankle fractures (UCS C) and three patella fractures (UCS F). Two fractures were treated conservatively and 16 were operated on. Only one patient had the implant revised. There were eight (44 %) failures over follow-up; none of the conservative treatment failed. The cumulative probability of failure for any reason was 27 % (8-52) and 55 % (22-79) at five and ten years, respectively. Conclusions Peri-prosthetic fractures around massive endoprostheses are different from that of standard implants. There are more type C fractures; internal fixation is an attractive option at the time of presentation but the risk of revision over follow-up is high and patients should be informed accordingly.