Three-dimensional computerized preoperative planning of acetabular prostheses implantation in total hip arthroplasty with Crowe IV type developmental dysplasia of the hip patients

Abstract

Objective To study whether 3D computerized pre-operative planning is accuracy and reliability in Crowe Ⅳ type developmental dysplasia of the hip （DDH） patients undergoing total hip arthroplasty （THA）. Methods Between September 2009 and February 2011, 20 Crowe Ⅳ type DDH patients （20 hips） were included in this study. The 3D pre-operative planning was performed using Mimics software to predict the acetabular component size, acetabular component abduction angle, hip rotation center position, the acetabular component coverage and number of patients received structural bone graft. The results were compared with traditional acetate templating technique and post-operative results. Results 70% （14/20） components were pre- dicted exactly and 30% （6/20） components were predicted with one size using 3D computerized planning, comparing with 25%（5/ 20） components were exactly, 45% （9/20） components were with one size and 30% （6/20） were with two size or more using conven- tional acetate templating technique. Statistically analysis revealed that 3D planning was more accuracy than templating technique regarding acetabular component prediction （t=-4.66, P=0.00）. There was no significant difference between the 3D computerized planned acetabular component abduction angle （3D plan 41.10°±4.87°, postoperative 44.98°±10.83°, t=0.88, P=0.42）, hip rota- tion center distance （horizontal distance： 3D plan 77.51±7.78 mm, postoperative 79.85±8.61 mm, t=-1.95, P=0.11; vertical distance： 3D plan 42.79±8.22 mm, postoperative 44.98±10.83 ram, t=-1.27, P=0.26）, acetabular component host coverage （3D plan 77.73%±10.51%, postoperative 78.98%±10.24%, t=-1.84, P=0.09）, and that found post-operatively. Five patients were consid- ered to need structural bone graft according to 3D computerized planning, which was highly coincident with the intraoperative find- ings in all five cases. Conclusion 3D computerized pre-operative planning using Mimics software is an accurate and reliable technique in treating Crowe Ⅳ type DDH patients undergoing THA. Key words: Hip dislocation, congenital; Arthroplasty, replacement, hip; Imaging, three-dimensional