Does introduction of a cemented polished taper-slip femoral stem reduce early periprosthetic fracture risk with anterior approach total hip arthroplasty? A case-matched study

Background: Anterior approach total hip replacement (AA-THA) is associated with higher periprosthetic fracture (PFF) risk. Cemented femoral fixation may reduce this risk. This study aims to (1) determine if using a cemented polished taper-slip (PTS) stem reduces PFF risk, (2) describe perioperative complications, and (3) identify factors associated with outcome. Methods: This was a retrospective, case-matched cohort study from an academic center. The first 122 hybrid AA-THAs with a minimum 12-month follow-up were reviewed. These were matched (1:2) for age, sex, BMI, femoral and pelvic morphology with 244 AA-THAs using an uncemented, short, stem. Outcomes measured include PPF (Vancouver classification) rate, reoperation rate, complications, cement quality, and radiologic measurements. Results: Nineteen PFFs (5.2%) occurred at a mean 14.5±23 days following surgery. There was no difference in PPF rate between groups (Cemented Stems: 7/122, 5.7%, 5/7 Type-A and 2/7 Type-B₂; Uncemented Stems: 12/244, 4.9%, 7/12 Type-A, 4/12 Type-B₂ and 1/12 Type-C; p = 0.847). There was no difference in PPF risk between short (≤ 125 mm) and normal length (150 mm) stems (p = 0.676). More uncemented stems subsided (Cemented stems: 1/122, 0.8%; Uncemented stems: 27/244, 11.1%; p < 0.001). Suboptimum cementation was noted in 16 (13%) hips; two fractured and one subsided (risk-ratio [RR]: 3.9; p = 0.035). A narrow ischial width and high ilio-ischial ratio were the only morphological parameters associated with risk of PPF and subsidence. Conclusion: Hybrid AA-THA did not reduce PFF risk. Suboptimal cementation was associated with increased risk of subsidence or fracture. Current instruments do not accommodate the limited working window and steeper femoral angle during AA-THA.