J. Arima et al., FEMORAL ROTATIONAL ALIGNMENT, BASED ON THE ANTEROPOSTERIOR AXIS, IN TOTAL KNEE ARTHROPLASTY IN A VALGUS KNEE - A TECHNICAL NOTE, Journal of bone and joint surgery. American volume, 77(9), 1995, pp. 1331-1334
The landmarks used to achieve correct rotational alignment of the femo
ral component in total knee arthroplasty may be indistinguishable or u
nreliable in the distal architecture of a valgus knee. Five observers
identified the anteroposterior axis, the posterior condylar axis, and
the transepicondylar axis in thirty cadaveric femora to determine the
reliability of the use of each axis in the operative setting. In addit
ion, radiographs were made of the distal aspect of each femur, the axe
s were constructed, and the angles were measured and compared with the
visual measurements made by the observers. A line drawn perpendicular
to the anteroposterior axis consistently approximated 4 degrees of ex
ternal rotation relative to the posterior condylar surfaces. The trans
epicondylar axis was more difficult to define and was not as accurate.
The radiographic results were similar to the visual results, but the
standard deviations for the former were less than those for the latter
. The anteroposterior axis appears to be a reliable landmark for rotat
ional alignment of the femoral component in a valgus knee.