Posterior-stabilized TKAs, which use a polyethylene tibial post to articulate against a metal femoral cam, are used regularly. Reported complications are related to the patellofemoral articulation or the tibial post-cam mechanism. Fracture of the tibial post is an uncommon but disabling complication after posterior-stabilized TKA that requires operative treatment.
The literature was reviewed to determine the frequency of tibial post fracture and address three questions: (1) Is there a specific prosthetic design or patient demographics in knees with a fracture of the tibial post? (2) What are the common presenting complaints and methods of diagnosis? (3) What methods of treatment have been used?
A PubMed search of English language articles from February 1982 to April 2010 was performed and 20 articles, all Level IV studies, were identified.
One specific design of posterior-stabilized tibial post with a central screw hole had a 12.4% incidence of fracture. Tibial post fracture has been reported with other designs, but with an incidence of 1% or less. The most common presenting symptoms include effusion, instability, or patella clunk syndrome. The most common method of diagnosis was clinical examination followed by arthroscopic examination. Treatment with revision to a new tibial polyethylene liner generally has been successful at short-term followup.
Tibial post fracture is a relatively uncommon complication after posterior-stabilized TKA that usually is treated successfully with liner exchange. The low quality of available literature makes it difficult to recommend a specific treatment protocol.