Utility of Hybrid Templating by Enlargement Rate of Hip Bone in Total Hip Arthroscopy

Abstract

Background/Objectives: This study is to investigate the enlargement rate of hip AP X-ray image to lower the errors occurred in the process of attaching calibration marker or calibration ball on the skin in case of hip AP X-ray test that is performed to measure the size of hip bone prior to the surgery in the patients who will undergo total hip arthroscopy, and to investigate the method of hybrid templating which can be applied to PACS with transparent acetate template used for conventional acetate templating in the hospitals where no program of digital templating is available.

Methods/Statistical analysis: To calculate the enlargement rate by height using X-ray device and to investigate the real height of hip joint, the height was measured using HIP 3D Sagittal Images of MRI. To compare the size of hip implant before and after the surgery, the sizes of acetabular cup, femur stem, and femur neck predicted by pre-surgery templating were compared with the real sizes of implants which were used.

Findings: The height of acrylic phantom was 1 cm, and enlargement rate was approximately 1% per cm. In HIP 3D Sagittal Images of MRI, mean height of hip joint were 99.23 mm and 98.38 mm in males and females, respectively. The height of hip joint from the slimmest subject in MRI was 80.30 mm while that from the most obese subject was 117.10 mm. With respect to the enlargement rate by height of hip joint,that from the slimmest subject was about 115% and that from the most obese subject was about 119%, demonstrating about 4% difference.

Improvements/Applications: To lower the errors of markers occurred in hip AP X-ray test that is performed prior to the surgery in the patients who will undergo total hip arthroscopy, the enlargement rate of hip AP X-ray image was investigated. Also, the utility of hybrid templating method applied to PACS with transparent acetate template was confirmed in the hospitals where digital templating was not available.