SURGICAL PEARLS: Revising a Failed UKA to TKA
Unicompartmental knee arthroplasty (UKA) is a great option for a subset of patients with osteoarthritis (OA) in a single compartment of the knee, as it is a reliable and durable operation when done well, said Rafael J. Sierra, MD, from Mayo Clinic, Rochester, Minnesota, at ICJR’s 7th Annual Revision Hip & Knee Course.
What’s up for debate, he said, is the difficulty in revising a UKA to a TKA, the survivorship of the revision, and patient satisfaction after the revision procedure.
A study just published in The Lancet found that that over a 5-year period, patients who undergo UKA have similar, if not a slightly better, clinical outcome compared with patients who undergo total knee arthroplasty (TKA), with substantial economic benefit. 
But not all studies agree: A systematic review of joint registry data from around the world found a higher revisions rate for UKAs than for TKAs.  And when revising a UKA to a TKA, the re-revision rate can be 4 times higher than the revision rate for primary TKA – and 13 times higher if the UKA is revised to another UKA, according to registry data from New Zealand. 
When UKAs fail, they fail for the following reasons:
- Implant loosening
- Progression of OA
- Problems with the polyethylene
The failure mechanism will dictate how difficult the revision will be, Dr. Sierra said, so surgeons should have everything they could need for a revision – such as constrained implants, stems, bone grafts, and augments – in the operating room when they start the procedure.
In his presentation, Dr. Sierra showed case examples of UKAs that required revision, gave his tips for improving the success of the revision procedure, and showed video of the technique he uses to remove the implants.
Click the image above to watch Dr. Sierra’s presentation and learn more about revising a failed UKA to TKA.
Disclosures: Dr. Sierra has no disclosures relevant to this presentation.
- Beard DJ, Davies LJ, Cook JA, et al. The clinical and cost-effectiveness of total versus partial knee replacement in patients with medial compartment osteoarthritis (TOPKAT): 5-year outcomes of a randomised controlled trial. Lancet. 2019 Jul 17. pii: S0140-6736(19)31281-4. doi: 10.1016/S0140-6736(19)31281-4. [Epub ahead of print].
- Labek G, Thaler M, Janda W, Agreiter M, Stöckl B. Revision rates after total joint replacement: cumulative results from worldwide joint register datasets. J Bone Joint Surg Br. 2011 Mar;93(3):293-7. doi: 10.1302/0301-620X.93B3.25467
- Pearse AJ, Hooper GJ, Rothwell A, Frampton C. Survival and functional outcome after revision of a unicompartmental to a total knee replacement: the New Zealand National Joint Registry. J Bone Joint Surg Br. 2010 Apr;92(4):508-12. doi: 10.1302/0301-620X.92B4.22659.