A new approach for the Martell 3-D method of measuring polyethylene wear without requiring the cross-table lateral films.
Due to the uneven and often inadequate quality of cross-table lateral hip radiographs, many radiographic studies of femoral head penetration into polyethylene in total hip arthroplasty are limited to the two-dimensional measurement of femoral head penetration using the A/P film only. We postulated that the use of two oblique frontal projections at 90 degrees to each other would improve the three-dimensional evaluation. Using an established hip phantom, the idealized accuracy and precision of the three-dimensional Martell method was evaluated, contrasting the standard A/P and cross-table lateral projections versus a pair of oblique projections by four independent readers. Accuracy and precision resulting from the use of two oblique projections (average accuracy +/-63 microm, precision +/-26 microm) were similar to that obtained using the conventional A/P and cross-table lateral views (accuracy +/-54 microm, precision +/-22 microm), though the results of the two oblique views were slightly more variable. These observations suggest that by using two oblique A/P projections, the major disadvantage of using the cross-table lateral films, namely the variable quality of the images, is avoided. Perhaps, therefore, the utility and availability of three-dimensional data in comparable clinical studies may be improved.
Bragdon
Charles R
CR
Orthopaedic Biomechanics and Biomaterials Laboratory and the Adult Reconstructive Unit of the Department of Orthopaedic Surgery of Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA. cbragdon@partners.org
Martell
John M
JM
Estok
Daniel M
DM
Greene
Meridith E
ME
Malchau
Henrik
H
Harris
William H
WH
D001175:Arthrography / Q000379:methods* / Q000592:standards; D019644:Arthroplasty, Replacement, Hip; D005270:Femur Head / Q000000981:diagnostic imaging*; D006621:Hip Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D066298:In Vitro Techniques; D019047:Phantoms, Imaging; D020959:Polyethylene; D011475:Prosthesis Failure; D015203:Reproducibility of Results
D020959:Polyethylene