Abstracts Posters SICOT-SOF meeting Gothenburg 2010 _2_

Poster
Topic: Arthroplasty - Hip
Abstract number: 25144
DIGTAL TEMPLATING IN TOTAL HIP ARTHROPLASTY: A MULTI CENTRE
TRIAL USING 2 DIFFERENT TEMPLATING SYSTEMS
Mahmoud HAFEZ 1 , Amr Mohsen ALI 2
1 The Orthopaedic Unit, October 6 University, Cairo (EGYPT), 2 Sheikh Zayed
Specialized Hospital, Cairo (EGYPT)
Templating in total hip arthroplasty (THA) is not new and it has long been used with
traditional radiographic films and printed templates (acetates). Digital templating has
become possible with the introduction of digital radiography and computers into
clinical practice. We present our experience in using digital templating in 100 patients
who underwent hip replacement in 3 centers using 2 different software systems;
Endopmap (Siemens) and Merge Ortho (Cedara). We used 6-step technique for
templating including; radiographic assessment , correction of magnification,
measuring leg length discrepancy, templating acetabular component, templating
femoral component, correction of leg length discrepancy and measuring length of
neck resection. The technical and outcome differences of the two software systems
were compared. We found several pitfalls of templating such as radiographic
magnification and abnormal positioning of the patient. External Rotation gave a false
impression of valgus leading to underestimation of the femoral offset. Internal rotation
gave a false impression of varus leading to overestimation of the femoral offset.
Abduction resulted in apparent lengthening and adduction resulted in apparent
shortening. Digital templating is a simple and less expensive form of computer
assisted surgery. It proves to be useful in identification of difficult or problematic
cases and prediction of component sizes, correction of leg length discrepancy,
restoration of normal hip centre, and optimization of femoral offset
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