Premium
Comparison of Femoral Angulation Measurement Between Radiographs and Anatomic Specimens Across a Broad Range of Varus Conformations
Author(s) -
Palmer Ross H.,
Ikuta Courtney L.,
Cadmus Jill M.
Publication year - 2011
Publication title -
veterinary surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 79
eISSN - 1532-950X
pISSN - 0161-3499
DOI - 10.1111/j.1532-950x.2011.00895.x
Subject(s) - medicine , radiography , cadaver , femur , deformity , nuclear medicine , orthodontics , anatomy , radiology , surgery
Objective To determine if measurement of anatomic lateral distal femoral angle ( aLDFA ) from radiographs is valid across a broad range of femoral varus conformations. Study Design Radiographic and anatomic study. Sample Population Large breed canine cadavers ( n = 5) and femora ( n = 10). Methods Cadavers were held in dorsal recumbency and 8 craniocaudal radiographic projections made of each femur: 1 image pre‐ and postosteotomy and at each of 6 progressive levels of induced distal varus deformity. Femurs were collected. Three blinded examiners independently measured varus on each radiograph ( R‐aLDFA ) and femoral specimen ( S‐aLDFA ) on 3 separate occasions. Intra‐ and interobserver variance in R‐aLDFA and S‐aLDFA measurements were determined. The strength of relationship between R‐aLDFA and S‐aLDFA and positive and negative predictive values for R‐aLDFA were calculated. Results Intra‐ and interobserver variance in R‐aLDFA (mean, 0.54% and 0.40%, respectively) and S‐aLDFA (mean, 0.43% and 0.41%, respectively) were acceptable. The strength of relationship between R‐aLDFA and S‐aLDFA (adjusted R 2 = 78.2%) was marginally below the acceptance criterion of 80%. Using aLDFA ≥ 102° as an indication for corrective femoral osteotomy, radiography was successful in correctly identifying corrective femoral osteotomy candidates (positive predictive value) and noncandidates (negative predictive value) 72% and 96% of the time, respectively. Conclusion R‐aLDFA did not reach the desired accuracy for femoral varus measurement across the range of conformations evaluated.