What features of stem increase the risk of intraoperative femoral fracture during cementless primary hip arthroplasty?

Cementless fixation has become increasingly popular in hip arthroplasty due to its shorter operation time, easier technique, biologic fixation, and avoidance of bone cement implantation syndrome compared to cemented fixation. However, intraoperative periprosthetic femoral fracture (IOPFx) is a disconcerting complication during cementless hip arthroplasty. Our purpose was to identify the features of cementless stem that increase the risk of IOPFx during primary hip arthroplasty.

We retrospectively reviewed all 4806 hip arthroplasties that was performed in a single institution from May 2003 to December 2020. Age at the index arthroplasty, sex, body mass index, physical status, ambulatory function, side of the operation, operational history, cause of the index arthroplasty, type of arthroplasty, surgical approach, surgeon, implant information, and events during the operation were investigated. The shoulder geometry and length of stem were also reviewed. The event of interest was narrowed down to IOPFx among various records of intraoperative events.

We found IOPFx of 2.6% among all the hips operated with cementless stem. In the multivariable analysis, female (OR = 1.52), childhood hip disease (OR = 2.30), stove-pipe femur (OR = 2.43), combined approach (OR = 2.60), and standard length of stem (OR = 1.59) were found to be significant risk factors of IOPFx.

In conclusion, a stem with a standard length is significantly associated with risk of IOPFx compared to a shortened stem. These findings highlight the importance of careful consideration in terms of the risk of IOPFx when standard length cementless stem is chosen.