Design and Manufacturing Preparation of a Patient Specific Acetabular Cage

Abstract:

Total hip arthoplasty or hip replacement is today a common and highly successful a surgical procedure. However, in the revision artoplasty the procedure is more complicated, as standard devices have to be adapted to different shapes of acetabular defects, which are patient specific especially when they are bigger and wider spread. This kind of big defects, sever acetabular defects, pelvic discontinuity, defects resulted from tumor problems, protrusion, can usually be addressed with a standard Burch-Schneider Antiprotrusio Cage or a Mueller Ring in order to restore the mechanics and the true center of the hip. This paper proposes a design process and manufacturing preparation for a patient specific acetabular cage. The design is intended to fix problems that standard cages sometimes do not resolve, for example insufficient fixation due to the fact that the inferior flange did not engage the ischium, problems of bone graft resorption and in the same time tries to remain an affordable solution. The design process uses as input information the 3D reconstruction of the patient hip from CT scan. Important parameters like the position of the true center of rotation, acetabular anteversion and inclination are determined and calculated. Other parameters, such as number of fixing screws and their designated holes or the amount of bone to be covered with the custom acetabular cage (fixation surface), are proposed by orthopaedic specialist. The design methodology relays on commercial software, such as Solid Works for CAD, 3D Doctor for 3D bone reconstruction from the CT scans or other software for different file transformations. The model was optimized to be produced through direct metal laser-sintering (DMLS). Regarding the results, the particular implant was designed and optimized for fabrication and it is available to be produced. During the design process, although a systematized process was undertaken and implemented, some activities could not be done in systematic, repeatable way. Nevertheless, a design process strategy was established, so that the design would match the requirements of such implant and also a requirements list for the type and form of information needed for this kind of design. Also, we concluded that using software to automate some of the operations that were done manually by the operator would help decrees the design time and improve the repeatability of the process.

• Periodical: Advanced Materials Research (Volume 837)
• Pages: 328-333
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.837.328
• Online since: November 2013
• Authors: Serban Costin, Constantin Anton Micu
• Keywords: Acetabular Component, Custom-Fit Design, Design Process, Patient Specific Implant, Rapid Prototyping (RP)

References

[1] J. V. Bono et. al. Revision Total Hip Arthroplasty. Springer-Verlag, 1999, pp.96-97, 160-162.

[2] C. Perka, R. Ludwig, Reconstruction of Segmental Defects During Revision Procedures of the Acetabulum With the Burch-Schneider Anti-Protrusio Cage., J. of Arthroplasty, 16, (2001) 568-574.

DOI: 10.1054/arth.2001.23919

[3] D. J. Berry, M. E. Müller. Revision arthroplasty using an anti-protrusio cage for massive acetabular bone defficienc, J Bone Joint Surg. (Br), 74-B 1992 711-715.

DOI: 10.1302/0301-620x.74b5.1527119

[4] T. J. Gill, J. B. Sledge, M. E. Müller, The Bürch-Schneider anti-protrusio cage in revision total hip arthroplasty indications, principles and long-term results. J Bone Joint Surg. 80-B, (1998) 946-953.

DOI: 10.1302/0301-620x.80b6.0800946

[5] W.G. Paprosky, P.G. Perona, J.M. Lawrence Acetabular defect classification and surgical reconstruction in revision arthroplasty: a 6-year follow-up evaluation. J. Arthroplasty 9 (1994) 33–44.

DOI: 10.1016/0883-5403(94)90135-x

[6] E. Sariali, S. Klouche, P. Mamoudy Investigation into three dimensional hip anatomy in anterior dislocation after THA. Influence of the position of the hip rotation centre, Clinical Biomechanics 27 (2012) 562-567.

DOI: 10.1016/j.clinbiomech.2011.12.014

[7] R.P. Pitto, A. Bhargava, Retroacetabular Stress-schielding in THA Clinical Orthopaedics and Related Research 466 (2008) 353-358.

DOI: 10.1007/s11999-007-0043-0

[8] A.L. Bell, D.R. Pedersen, R.A. Brand, A comparison of the accuracy of several hip center location prediction methods. Journal of Biomecanics, 23 617-621.

DOI: 10.1016/0021-9290(90)90054-7

[9] http: /www. eos. info/. [Online].

[10] T.A. Ahmed, M. Long, J. Silverstri, A New Low Modulus Biocompatible Titanium Alloy. Science and Technology 1996 1760-1767.

[11] S. Nag, R. Banerjee, Fundamentals of Medical Implant Materials in: R. Narayan (Ed. ) ASM Handbook, vol 23. Materials for Medical Devices. ASM International, (2012).