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Potential
shortcomings
of Off-the-shelf TKA
Patient dissatisfaction following off-the-shelf
TKA is up to 20%. It is unclear what variables
are relevant to improve results of TKR.
Potential factors are:
- Implant overhang [1]
- Malrotation of femoral and tibial components
[2, 3, 4]
- Unreliable surgical anatomic landmarks
- Joint line is not restored
- Asymmetric distal condylar geometry is
replaced with a symmetric condylar design
- Distal condylar valgus is not restored given
the high variability [5] (fig. 1)
- Proximal tibial condylar anatomy is not
restored [5] (fig. 2).
Custom anatomic CR TKR
W. Fitz
Fig. 1: The distal femoral condyle
has a larger range of varus or
valgus than just 5 or 7 degrees.
Comparing osteoarthritic (n=80)
with non-osteoarthritic patients
(n=356) the mean 5.4°, ± 3.3
(6° varus to 11° valgus) and 5.2 °,
± 3.0 (3° varus to 13° valgus) in the
control group 14.