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Ultraporous cups, augments and cages may provide fixation for complex acetabular reconstruction
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PARK CITY, Utah — Use of ultraporous cups, augments and cages may provide fixation during revision total hip arthroplasty and in patients with musculoskeletal tumors in which major bone loss involving the acetabulum is present, according to a presenter at the Joint Arthroplasty Mountain Meeting.
According to David G. Lewallen, MD, cementing the acetabular liner into the shell can create a locking screw effect while porous cups provide antibiotic delivery. He also noted use of an array of screws is important.
“You should have an array of screws that start peripheral, become a little more polar as you come down and then end up peripheral at the base of the ischium,” Lewallen said in his presentation.
To keep the cup from rocking vertical and rolling out, Lewallen noted some screws need to be placed in zone 3.
Developed as a prosthetic structural allograft, highly porous metal augments can be used in patients with major defects and regular defects, poor bone quality and disassociations.
“I was unhappy with our results of allografts in my own personal experience with those resorbing and failing us when we really needed them, and the idea was to try to make a femoral head allograft that was a prosthetic material,” Lewallen said.
If fixation is still inadequate, Lewallen noted a half or full acetabular cage can be placed over the top of the acetabular component before cementing a polyethylene liner in place.
“The strategy here is simple: You want to maximize contact on host bone. You want to get good fixation, so the cup does not move around and you want to have adaptability for the multiple different defects you are going to encounter because they are all a little bit different,” Lewallen said.
Treatment for complex acetabular reconstruction is like custom carpentry, according to Lewallen. Although the principles may be easy to understand, he noted the challenge is achieving the principles.
“There is no one way to do a revision case. There are many different ways to solve the problem,” Lewallen said. “You need to find a tool kit that works for you; but I guarantee you that [if] you satisfy those principles, [you] will have success and if you do not, you will have heartache along with your patients.” – by Casey Tingle
Reference:
Lewallen DG. Ultraporous cups/augments and cages are all you need for complex acetabular reconstruction. Presented at: Joint Arthroplasty Mountain Meeting; Feb. 10-13, 2019; Park City, Utah.
Disclosure: Lewallen reports he is a paid consultant for Acuitive Technology and Zimmer Biomet, has stock or stock options with Acuitive Technologies and Ketai Medical Devices, is a board or committee member for the American Joint Replacement Registry and Orthopaedic Research and Education Foundation and received IP royalties from Mako/Stryker and Zimmer Biomet.