At least four ways have been described to determine
femoral component rotation, and three ways to determine tibial component
rotation in total knee replacement (TKR). Each method has its advocates
and each has an influence on knee kinematics and the ultimate short
and long term success of TKR. Of the four femoral component methods,
the author prefers rotating the femoral component in flexion to
that amount that establishes a stable symmetrical flexion gap. This
judgement is made after the soft tissues of the knee have been balanced
in extension. Of the three tibial component methods, the author prefers rotating
the tibial component into congruency with the established femoral
component rotation with the knee is in extension. This yields a
rotationally congruent articulation during weight-bearing and should
minimise the torsional forces being transferred through a conforming tibial
insert, which could lead to wear to the underside of the tibial
polyethylene. Rotating platform components will compensate for any
mal-rotation, but can still lead to pain if excessive tibial insert
rotation causes soft-tissue impingement. Cite this article:
PCL retaining fixed-bearing TKA is a highly successful
operation with the need for more surgery occurring at the rate of
approximately 0.4% per year over the first 27 years. The most common
cause for revision surgery is related to polyethylene insert failure
and accounts for approximately 50% of re-operations. Late metastatic
infection is the next most frequent cause followed by patellar problems,
late instability and component loosening in decreasing frequency.
A myriad of rare miscellaneous problems can also occur.