BACKGROUND: The best treatment method for large tibial bone defects
during revision knee replacement has not been established. The purpose of this
study was to determine the initial results obtained with a unique
reconstructive implant, the porous tantalum metaphyseal cone, designed as an
alternative treatment for severe tibial bone loss following total knee
METHODS: Porous tantalum metaphyseal cones were implanted during
fifteen revision total knee replacements in eight women and seven men who had
an average age of 68.1 years at the time of the procedure. The patients had
had an average of 3.5 prior total knee replacements. According to the Anderson
Orthopaedic Research Institute bone defect classification, eight knees had a
Type-3 defect and seven knees had a Type-2B bone defect. All patients were
followed clinically and radiographically.
RESULTS: The patients were followed for an average of thirty-four
months (range, twenty-four to forty-seven months). Overall, the average Knee
Society clinical scores improved from 52 points preoperatively to 85 points at
the time of the final follow-up. At the final follow-up evaluation, all
fifteen porous metaphyseal cones showed evidence of osseointegration with
reactive osseous trabeculation at points of contact with the tibia. There was
no evidence of loosening or migration of any of these tibial reconstructions
at the time of final follow-up.
CONCLUSIONS: At the time of short-term follow-up, the porous
tantalum metaphyseal tibial cones effectively provided structural support for
the tibial implants in this series. The potential for long-term biologic
fixation may provide durability for these tibial reconstructions. Long-term
follow-up and comparison with alternative reconstructive techniques will be
required to evaluate the true effectiveness of this treatment approach.
LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions
to Authors for a complete description of levels of evidence.