Rw. Wright et Sj. Luhmann, THE EFFECT OF KNEE EFFUSIONS ON KT-1000 ARTHROMETRY - A CADAVER STUDY, American journal of sports medicine, 26(4), 1998, pp. 571-574
We studied five fresh-frozen lower extremity cadaveric specimens to as
sess the effect of knee effusions on KT-1000 arthrometry, Part 1 consi
sted of serial 10-ml injections (up to 100 mi) of saline into each kne
e and measurements of midpatellar knee circumference and anterior disp
lacement using the KT-1000 arthrometer at 67, 89, and 134 N after each
10-ml increment. Part 2 consisted of evacuation of the saline and tra
nsection of the anterior cruciate ligament through a 2-cm medial parap
atellar arthrotomy, Each knee again underwent the part 1 protocol, Seq
uential injections in parts 1 and 2 showed incremental increases in kn
ee circumference and KT-1000 arthrometer measurements for all three fo
rce levels. A 3-mm increase in anterior translation compared with the
value at 0-ml injection was obtained by the 70-ml injection point in b
oth groups. At the 70-ml injection point, the patella was ballottable,
thereby affecting anterior measurements-despite posterior force on th
e patella sensor pad-because of the KT-1000 arthrometer reference leve
l at midpatella. This increase in KT-1000 arthrometer readings could e
rroneously imply anterior cruciate ligament disruption in the clinical
situation of right-to-left comparison. We conclude that clinicians us
ing the KT-1000 arthrometer should aspirate knees that have effusions
and a ballottable patella to minimize false-positive readings.