SURGICAL PEARLS: Acetabular Cup Removal in Revision THA
The process of safely and efficiently removing the acetabular cup is an important part in any revision total hip arthroplasty (THA), regardless of the reason for the revision. There are 4 critical steps in this process, David G. Lewallen, MD, told attendees at ICJR’s 8th Annual Revision Hip & Knee Course, including:
Exposure. As Dr. Lewallen said, anything is more difficult if you can’t see what you’re doing. In revision THA, ensure adequate exposure – including being able to see the peripheral rim of the acetabulum – before attempting to remove the cup.
Polyethylene liner removal. Some systems have cup-specific extraction tools, others have various ways of interacting with the locking mechanism or tab to remove the polyethylene liner. Sometimes they work, sometimes they don’t, Dr. Lewallen said. If they don’t work, a hole can be drilled in the polyethylene liner and a screw can be used to remove the cup. But with today’s thinner polyethylene, that may not be possible. If nothing else works, ream out the cup, Dr. Lewallen said.
Screw removal. This is usually a routine step – unless the screws have been stripped. In that case, Dr. Lewallen said, burr away the screw head and then countersink it with the cutting tool to move it out of the way.
Dividing the connection of the cup to the bone. This is a basic but essential skill needed to do revision THAs properly. Dr. Lewallen said his practice has had many referred revision cases in which bone loss was exacerbated by a surgeon attempting and failing at this stage of the procedure. A well-fixed cementless cup can be removed with a device that is essentially a system of curved blades that are held against the edge of the cup by a ball placed inside the cup, usually with a trial liner. Dr. Lewallen emphasized that this is a step in the procedure that should be done slowly and carefully to avoid damaging fragile bone.
Click the image above to watch Dr. Lewallen’s presentation, including a surgical video demonstrating how to safely divide the bony attachment at the backside of the cup.
David G. Lewallen, MD, is a Professor of Orthopedics at Mayo Clinic, Rochester, Minnesota.
Disclosures: Dr. Lewallen has disclosed that he receives royalties from and is a paid consultant for Acuitive Technologies and Zimmer Biomet.