Independent Risk Factors for Periprosthetic Femoral Fracture after Total Knee Arthroplasty: A Retrospective Cohort Study on the Role of Anterior Femoral Notching (≤3 mm)
Wei-Kang Wong, Fang-Yu Chu, Hung-Yen Chen, Jiun-Liang Chen, Yao-Hung Tsai, Kuo-Ti PengAbstract
Background:
Anterior femoral notching (AFN) >3 mm during total knee arthroplasty (TKA) has traditionally been considered a risk factor for periprosthetic femoral fractures (PFF). However, clinical observations suggest fractures can occur with minimal notching, warranting investigation into additional risk factors.
Objectives:
This study aimed to evaluate the association between AFN ≤3 mm and the risk of PFF following total knee arthroplasty (TKA), and to identify additional independent risk factors.
Materials and Methods:
A retrospective cohort study analyzed 3342 consecutive TKA procedures (2018–2024). After excluding 10 cases with AFN >3 mm, 3332 patients were stratified into non-AFN (
Results:
The overall PFF rate was 0.87%. The fracture incidence was significantly higher in the AFN ≤3 mm group (7.90%; 6/76) compared to the non-AFN group (0.70%; 23/3,256). Notably, half of the fractures (3 of 6) in the AFN ≤3 mm group occurred in patients with rheumatoid arthritis (RA). Interestingly, no fractures occurred in the excluded deep AFN cohort. While factors like prosthesis brand or systemic comorbidities were not significant, both RA (
Conclusions:
This study suggested that in addition to AFN depth, identifying RA and low BMD as the two primary independent predictors for PFF. We found a crucial synergistic effect: In patients with RA, even AFN ≤3 mm becomes a critical fracture trigger. These findings suggested that preoperative risk stratification could benefit from incorporating a comprehensive assessment of patient-specific factors beyond surgical geometry. This approach may be particularly relevant for all patients, especially females, who require careful assessment due to their higher prevalence of low BMD, despite a direct gender link not being found in our cohort.