J Korean Hip Soc JKHS The Journal of the Korean Hip Society 1226-9409 The Korean Hip Society 10.5371/jkhs.2010.22.1.73 Original Article Comparison of Conventional and Digital Templating Technique in Total Hip Arthroplasty Hwang Sung Kwan MD PhD Kang Dong Hyun MD Cho Tae Yeon MD Lee Chang Ho MD Department of Orthopedic Surgery, Wonju College of Medicine, Yonsei University, Wonju, Korea. Address reprint request to Sung Kwan Hwang, MD. Department of Orthopedic Surgery, Yonsei University Wonju College of Medicine, 162 Ilsan-dong, Wonju 220-701, Korea. TEL: +82-33-741-1351, FAX: +82-33-746-7326, hwtonlka@yonsei.ac.kr 03 2010 31 03 2010 22 1 73 78 27 07 2009 20 10 2009 30 11 2009 Copyright © 2010 The Korean Hip Society 2010 Purpose

To examine the effectiveness of digital templating in patients who underwent primary total hip arthroplasty by comparing and analyzing the accuracy of acetate and digital templating.

 Materials and Methods

One hundred and nine patients who underwent primary total hip arthroplasty between November 2002 and May 2006 were assigned to the acetate templating group (group I), and 113 patients between June 2006 and April 2009 were assigned to the digital templating group (group II). The sizes of the acetebular cup and femoral stem were examined to determine the accuracy of each method.

 Results

In group I, acetabular cup accuracy was found in 46.8% of cases, and 94.5% showed a mismatch less than ±1 sizes. In the case of the femoral stem, accuracy was found in 53.2% and 92.7% showed a mismatch. In group II, acetebular cup accuracy was observed in 43.4% of cases, and 92.9% showed a mismatch below ± 1 size. In femoral stem cases, 46.9% were accurate and 93.8% showed a mismatch.

 Conclusion

The accuracy of the digital templating method is equivalent to that of acetate templating, and should replace acetate templating before the operation.

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Preoperative radiograph of a 52 years old male shows avascular necrosis. (A) This shows measuring acetabular cup by acetate templating using acetate film. (B) This shows measuring femoral stem by acetate templating using acetate film. (C) Postoperative radiograph of total hip arthroplasty shows stable fixation (exactly correct size).

Preoperative radiograph of a 54 years old female shows avascular necrosis. (A) Scaling. (B) Planning-correction of pelvis tilt based on transischial line. (C) Planning-measuring size of femoral head and femoral canal. (D) Templating-visualization of measured implant.

Demographic Data of Group 1, Group 2

Accuracy between Templated Size and Actual Implant Size according to Component Type in Two Groups.