ABSTRACT
PURPOSE: Inaccurate femoral canal shaping can result in post-operative complications in hip arthroplasty. We addressed the amount of broach rotation during shaping of the femoral canal and compared it with respect to newly designed broaches which were modified to minimize the rotation. MATERIALS AND METHOD: we designed the broaches that had canal guide which restricts the broach motion such that it is always aligned with the femoral axis while the broach machines the metaphyseal bone. Conventional broaches and the modified broach applied to 5 pair of fresh-frozen cadaver femurs and its spatial motion was measured with motion tracker. Rotations in coronal, saggital and frontal plane during the final 10 mm of broach advance were measured. RESULTS: 2.4..of axial rotation was occurred during final 10 mm advance of broach in the conventional method, which was the largest component of the rotation. Rotation of the broach during machining was decreased to 37% (p=0.075) and 25% (p=0.042) in the sagittal plane and coronal plane, respectively, by proposed method. CONCLUSION: The canal guide in the proposed method significantly reduced the rotation of the broach without any extra incision or measurement devices, resulting in increased accuracy in the femoral canal shaping.