Periprosthetic Femur Fracture Risk: Influenced by Stem Choice, Not Surgical Approach.

BACKGROUND: Periprosthetic femur fracture (PFF) remains a common reason for failure after total hip arthroplasty (THA). For over 10 years, our institution has performed both anterior approach (AA) and posterolateral (PL) approaches for primary THA with multiple stem designs. The aim of this study is to determine the 90-day relative risk of PFF with regard to approach and stem design.

METHODS: A retrospective review of our institutional database was performed on all patients undergoing primary THA from 2007 to 2018 using AA or PL approaches. Five surgeons performing 6309 THAs (AA = 4510; PL = 1799) using single-wedge taper (n = 2417) or fit-and-fill (n = 3892) stems were included. PFF occurring within 90 days of the index procedure were analyzed. Differences in PFF rates, fracture location, stem type, and treatment method were assessed. Comparisons were made using a Cox regression analysis.

RESULTS: The 90-day revision rate for fracture was 0.3%. Clinically significant fractures requiring cerclage cabling, stem change, revision, or open reduction internal fixation occurred in 0.9% of patients (intraoperative = 37, 0.6%; postoperative = 17, 0.3%). Cox regression found PFF risk was significant for female patients (P = .008), patients older than age 65 (P < .01), single-wedge taper stems (P = .05), and for cases with collarless stems (P = .04). Among PFF cases that required surgical intervention, risk factors were female sex, age older than 65, and body mass index under 25 (P < .05). Collarless stems were 2.6 times more likely to result in PFF than collared stems (P = .04). Single-wedge taper stems were 2.3 times more likely to result in PFF than fit-and-fill stems (P = .05). Approach was not found to be an independent risk factor for PFF (P = .85).

CONCLUSION: Our single-center experience demonstrates the risk of periprosthetic fracture within 90 days of surgery is significantly lower with collared stems and fit-and-fill stem designs. Female sex, age over 65, and body mass index below 25 nearly double the PFF risk. Surgical approach did not influence fracture rates.