Fracture risk during extraction of well-fixed extended cementless stems : porous versus hydroxyapatite coated

The concern of extensive fracturing and bone damage during implant removal has been reported for ingrowing stems, in particular in extended porous coated stems, potentially impeding successful re- implantation of a femoral revision implant and consequently debilitating patients for life. The aim of the present study is to describe this particular complication and comparing the occurrence in porous coated and hydroxyapatite (HA) coated femoral implants. 62 consecutive revision hip replacements were per- formed between January 2010 and December 2016 at a single academic institution. Only revisions of a primary total hip replacement were included. All surgeries were performed by the same senior surgeon. Clinical follow-up involved examination with the Harris hip score (HHS) at 2 years post surgical intervention. Fracture occurrence and severity were compared between groups by means of the Vancouver classification for intraoperative fractures. Overall, significant higher rates of fracturing were observed in the porous coated group (81.8%, p<0.05) compared to the HA coated group (43.5%, p<0.05). Of these fractures, the majority (72,7%) were B3 fractures. There was a significant difference between the mean HHS in the porous-coated group versus the group with HA coating (mean Harris Hip Scores of 68,45 vs 86,17, p = .004). Surgeons have to be wary with implanting porous coated stems in primary hip arthroplasty, especially in younger patients who have a high likelihood of future revision surgery, due to the catastrophic peri-operative fractures associated with the removal of these stems.