Complications and survival of conversion to total hip arthroplasty after failed primary osteosynthesis compared to primary total hip arthroplasty in femoral neck fractures

Surgical treatment options for patients with an intracapsular fracture of the femoral neck (FFN) are primary osteosynthesis as a femoral head-spearing technique or primary (hemi)arthroplasty. The most common complications after primary osteosynthesis, such as avascular necrosis (AVN) or non-union, can result in conversion to Total Hip Arthroplasty (cTHA). Data concerning complications and survival rates of cTHA in comparison to primary Total Hip Arthroplasty (pTHA) after FFN are limited due to the absence of well-designed studies.A multicentre retrospective cohort study was conducted in three Dutch hospitals comparing the rate of postoperative dislocations, periprosthetic fractures, prosthetic joint infections, blood loss during surgery (>1000 mL), postoperative cardiac- and pulmonary complications after pTHA and cTHA in the first year after surgery. As a secondary outcome implant survival of pTHA and cTHA in terms of revision rates was evaluated.In total 548 patients were included (pTHA n = 264 and cTHA n = 284) with a mean follow-up of 5 years (±3.5 SD). No significant differences were found in postoperative complications rates. The revision rate in the pTHA group was 7.2% in comparison to 7.7% in the cTHA group (p = 0.81). No difference in the short-term implant survival was found between both groups (p = 0.81).This study showed no significant differences in terms of postoperative complication rates in the first year after pTHA and cTHA in patients with FFN. Also, no significant difference in short-term implant survival of primary and conversion total hip arthroplasty was found.