Preoperative templating is an important part of a THA. The ability to accurately determine magnification of the hip on the
radiograph and apply identical magnification to the radiograph and template will improve accuracy of preoperative templating
of THA. We designed a templating method using a new way of determining the hip magnification with a linear relationship between
magnification of the hip and the reference object on top of the pubis symphysis; the relationship was determined on 50 radiographs.
We then compared our method with two other templating methods: an analog method assuming an average hip magnification of 15%
and a digital method determining the hip magnification with a one-to-one relationship between the reference object and the
hip. All methods were reproducible. Uniform undersizing occurred when templating with the digital method based on the one-to-one
relationship; the analog method best predicted the implanted prosthesis size, closely followed by our new digital templating
method; the new method will be particularly applicable for preoperative THA when analog methods are replaced by digital methods.
Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest,
patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.
Each author certifies that his or her institution either has waived or does not require approval for the human protocol for
this investigation and that all investigations were conducted in conformity with ethical principles of research.