Topography of the periacetabular bone in Chinese patients - do current cages fit?

Background: Understanding the anatomy of the periacetabular bone is critical for designing and implanting cages, as well as reconstruction of lost periacetabular bone. We aimed to study the topography of periacetabular bone and compare it with current cages to examine their fit in a Chinese population.

Methods: We performed three-dimensional measurement on computed tomography images of 105 hemipelves to delineate the topography of the periacetabular bone. We compared the bone with digital models of commercially available cages, and divided the results into three scenarios (fit, mismatch and unfit) according to absence or existence of overhang and the extent of contouring needed after implanting the cages to the pelves.

Results: Our measurement provided a representation of normal topography of the periacetabular bone. Only 21% of the patients studied had commercially available cages which fit their pelves, whilst there was no cage that fitted 59% of the patients even after extensive contouring.

Conclusion: Current acetabular cages have low fit rates for the periacetabular bone in Chinese patients.