In the absence of a specific ICD code for AFSF, the femoral radiographs of all the patients listed in the hospital's administrative database with a code for subtrochanteric or diaphyseal femur fracture between June 1st, 2009, and January 31st, 2017, were reviewed.
The femoral bow and medial and lateral cortical thickness of AFSF group were compared with control group.
And, then, we used correlation analysis with age and analysis of covariance (ANCOVA) for correction of age with femoral bow, CTI, medial CTI, and lateral CTI as dependent variables and AFSF as an independent variable and age as a covariate.
All AFSF patients were female and all had a history of BP use with a mean duration of 7.3 years (range 1-17 years).
Radiographic Difference of Femoral Bow and Cortical Thickness between AFSF and TFSF.
The mean lateral CTI of AFSF group (0.323 [+ or -] 0.042) was significantly higher than control group (0.267 [+ or -] 0.041) (P < 0.0001, after age correction P < 0.0001).
In this retrospective case-control study, we evaluated femoral bow and femoral shaft cortical thicknesses at the thickest portion of lateral femoral cortices in 29 postmenopausal BPs-associated AFSF patients (42 femurs), comparing them with control group of 22 TFSF patients (22 femurs) as well.
We found that femoral bows of AFSF group were significantly higher than control group on both AP and lateral radiographs, regardless of age correction.
Possible explanation for an increased femoral bow of AFSF patients is the biomechanics affecting bowed femurs.
We found no significant difference in medial cortical thickness between AFSF group and control group.
AFSF are rare events (as exemplified by our small sample size) thus justifying a case-control design.
AD AFSC (x [10.sup.5]) (x [10.sup.5]) Sp 1 1.922 10.69 9.00 * Season (S) 3 1.798 1.56* 0.40 Period (P) 3 0.632 40.91 9.11 * P * Species 3 2.736 17.04* 4.11 * Residual 98 1.094 3.6 0.60 SV AFSF
ALSC ALSF (x [10.sup.5]) (x [10.sup.5]) (x [10.sup.5]) Sp 1.17 4.41 2.28 Season (S) 0.60 1.87 * 1.42 Period (P) 11.35 * 36.80 30.15 * P * Species 4.76 * 28.00 * 19.27 * Residual 0.84 3.33 3.28 SV SPP FSPP IM (x [10.sup.5]) (x [10.sup.5]) Sp 3.18 148.92 * 0.12 Season (S) 3.42 1.33 19.34 Period (P) 16.75 * 9.01 * 86.32 P * Species 11.46 * 3.71 * 40.67 Residual 2.77 1.07 25.16 * p<0.05.