Aseptic tibial debonding as a cause of early failure in a modern total knee arthroplasty design.
BACKGROUND
We observed isolated tibial component debonding from the cement in one modern primary TKA design (NexGen LPS 3° tibial tray; Zimmer, Warsaw, IN, USA). This failure mechanism is sparsely reported in the literature.


OBJECTIVE
We (1) assessed survivorship of this tibial tray with special emphasis on debonding; (2) described clinical and radiographic features associated with tibial failure; and (3) compared patient and radiographic features of the failures with a matched cohort.


METHODS
A total of 1337 primary TKAs were performed with a cemented NexGen LPS 3° tibial tray over an 11-year period. Twenty-five knees (1.9%) were revised for tibial debonding. BMI and radiographic alignment in the tibial debonding group were compared with a matched control group. Implant survivorship was assessed using tibial debonding as the end point.


RESULTS
Survival free of revision from tibial debonding was 100% at 1 year and 97.8% at 5 years. The tibial failures shared a typical radiographic pattern with debonding at the cement-implant interface and subsidence into varus and flexion. We found no link between limb alignment or individual component alignment and failure because 22 of the 25 failures occurred in well-aligned knees.


CONCLUSIONS
Our standardized followup of patients undergoing TKA at routine intervals allowed us to discover a higher rate of revision resulting from tibial debonding. We have discontinued the use of this particular tibial tray for primary TKA and surveillance for patients undergoing TKA continues to be warranted.
Department of Orthopedic Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
Diren
D
Arsoy
Mark W
MW
Pagnano
David G
DG
Lewallen
Arlen D
AD
Hanssen
Rafael J
RJ
Sierra
D000328:Adult; D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D001843:Bone Cements; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation; D012189:Retrospective Studies; D013977:Tibia / Q000601:surgery*; D016896:Treatment Outcome
D001843:Bone Cements