Predicting the underestimation of the femoral offset in anteroposterior radiographs of the pelvis using 'lesser trochanter index': a 3D CT derived simulated radiographic analysis.
We developed 'lesser trochanter index' (LTI) and estimated its accuracy in predicting the underestimation of offset in the anteroposterior (AP) pelvic radiographs. We reconstructed 320 simulated radiographs from the CT scans of 40 adult hips at different rotational projections of 10° increments from 30° internal rotation to 40° external rotation. Underestimation of femoral offset as a percentage was derived from the neck profile angle for all radiographs. Radiographs with an LTI value above 35 were 94% (95% CI, 89%-97%) likely to underestimate femoral offset by more than 5%. Radiographs with LTI between 0 and 30 demonstrated femoral offset within 5% of the true offset (predictive value 100%, CI 87%-100%). LTI could be a useful guide in preoperative templating of hip arthroplasty.
Department of Trauma and Orthopaedics, King's College Hospital, London, United Kingdom.
Krishna
K
Boddu
Department of Trauma and Orthopaedics, King's College Hospital, London, United Kingdom.
Martin
M
Siebachmeyer
Department of Trauma and Orthopaedics, King's College Hospital, London, United Kingdom.
Sandesh
S
Lakkol
Department of Trauma and Orthopaedics, King's College Hospital, London, United Kingdom.
Brathaban
B
Rajayogeswaran
Department of Trauma and Orthopaedics, King's College Hospital, London, United Kingdom.
Venu
V
Kavarthapu
Department of Trauma and Orthopaedics, King's College Hospital, London, United Kingdom.
Patrick L S
PL
Li
D000328:Adult; D000368:Aged; D003198:Computer Simulation; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging*; D006621:Hip Joint / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010384:Pelvic Bones / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed
AP radiographs; femoral offset; lesser trochanter index; pre-operative templating