Risk Factors for Periprosthetic Femur Fracture and Influence of Femoral Fixation Using the Mini-Anterolateral Approach in Primary Total Hip Arthroplasty.

Background: The mini-anterolateral (AL) approach for total hip arthroplasty (THA) has gained popularity. In contrast to other approaches, risk factors for periprosthetic femur fractures have not been well established for the AL approach.

Methods: Six hundred eighty-four primary THAs performed using the AL approach were retrospectively reviewed for risk factors associated with perioperative periprosthetic femur fractures within 3 months of surgery. Risk factors evaluated were gender, age, body mass index, laterality, and Dorr ratio of the proximal femur. Cemented stems and collared uncemented stems were compared to uncemented tapered-wedge and meta-diaphyseal stems. A Student's t-test was used for continuous variables, and a chi-squared test was used for categorical variables.

Results: Of 684 primary THAs performed, 57 (8.3%) resulted in fracture. Twenty-eight (4.1%) occurred intraoperatively and 29 (4.2%) occurred postoperatively within 90 days. All intraoperative fractures were fixed at the time of surgery and healed uneventfully. Of the postoperative fractures, 15 (2.2%) were amenable to nonoperative management and healed. Fourteen (2.0%) required revision arthroplasty. There was a significantly lower rate of fracture in patients receiving cemented or collared stems (0%, n = 101) than in those receiving tapered-wedge or meta-diaphyseal fitting stems (9.8%, n = 583; P = .0009). Odds of fracture increased with female gender (P = .0063) and increasing Dorr ratio (P = .0003). Analysis showed a trend toward increased risk with older age, but did not achieve statistical significance. Body mass index and laterality showed no statistically significant effect.

Conclusion: Performing primary THA via the AL approach, 2.0% of patients had a postoperative fracture requiring revision within the first 3 months. With cemented and collared stems, the fracture rate was significantly lower. Surgeons should consider using cemented or collared stems in high-risk patients.