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Radiographic Evaluation of BFX Acetabular Component Position in Dogs
Author(s) -
Renwick Alasdair,
Gemmill Toby,
Pink Jonathan,
Brodbelt David,
McKee Malcolm
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.2011.00824.x
Subject(s) - medicine , radiography , inclinometer , orthodontics , femoral head , acetabulum , nuclear medicine , anatomy , surgery , geodesy , geography
Objective: To assess the reliability of radiographic measurement of angle of lateral opening (ALO) and angle of version of BFX acetabular cups. Study Design: In vitro radiographic study. Sample Population: BFX cups (24, 28, and 32 mm). Methods: Total hip replacement constructs (cups, 17 mm femoral head and a #7 CFX stem) were mounted on an inclinometer. Ventrodorsal radiographs were obtained with ALO varying between 21° and 70° and inclination set at 0°, 10°, 20°, and 30°. Radiographs were randomized using a random sequence generator. Three observers blinded to the radiograph order assessed ALO using 3 methods: (1) an ellipse method based on trigonometry; (2) using a measurement from the center of the femoral head to the truncated surface of the cup; (3) by visual estimation using a reference chart. Version was measured by assessing the ventral edge of the truncated surface. Results: ALO methods 2 and 3 were accurate and precise to within 10° and were significantly more accurate and precise than method 1 ( P <.001). All methods were significantly less accurate with increasing inclination. Version measurement was accurate and precise to within 7° with 0–20° of inclination, but significantly less accurate with 30° of inclination. Conclusions: Methods 2 and 3, but not method 1, were sufficiently accurate and precise to be clinically useful. Version measurement was clinically useful when inclination was ≤20°.