Biomechanical principles in designing custom-made hip prosthesis

Abstract

Total hip replacement has increasingly become popular in treating osteoarthritis, relieving pain, restoring joint function and correcting the deformities. However, due to the wide variations of the anatomy in femoral bone between individuals, the commonly used off-the-shelf standard hip stems cannot consistently achieve the good fit, thus the clinical outcome is compromised. On the other hand, an increasing demand for restoring the normal life quality after total hip replacement including play sports and other activities, especially with the coming era of the precision medicine and digital orthopaedics, and the availability of the advanced surgical navigation systems and 3-D printing technologies, the patient-specific hip prostheses have become ever favourable. The rationale for using the custom stem is not only for the complex cases, but also for the routine cases in order to achieve better clinical outcomes and longer survivorship. This chapter will focus on how to design a custom hip stem for an individual patient based on the bone geometry, deformities and pathological conditions. The advantages and disadvantages of each design options are considered and analysed.