Association of KT-1000 measurements with clinical tests of knee stability 1 year following anterior cruciate ligament reconstruction.
METHODS
Prospective, observational study.


OBJECTIVE
To determine the association between KT-1000 measurements with an anterior translation force of 89 N and other measures of outcome (the Tegner activity score, the modified Lysholm score, subjective rating of instability, Lachman test, and pivot-shift test) 1 year following anterior cruciate ligament (ACL) reconstruction.


BACKGROUND
Health care professionals often use the side-to-side difference measured with the KT-1000 arthrometer to determine ACL integrity during passive motion. It has been postulated that a 5-mm or greater difference between impaired and nonimpaired knees represents a procedural failure.


METHODS
Ninety patients (46 men, 44 women) with a mean age of 30 +/- 8 years were examined 1 year after surgery. Patients were classified in 1 of 3 groups depending on the amount of laxity between the impaired knee and the nonimpaired knee. Seventy percent of the subjects had a side-to-side difference less than or equal to 3 mm (tight), 13% had a difference of between 3 and 5 mm (moderate), and 17% had a difference greater than or equal to 5 mm (loose) on examination using the KT-1000.


RESULTS
Mean Lysholm and Tegner scores did not differ significantly among groups. Side-to-side differences in KT-1000 measurements at 89 N were not associated with the Lysholm score (r = -0.09) or Tegner score (r = 0.02). Lachman tests were related to involved-knee KT-1000 measurements (r = 0.39) but not to side-to-side differences in KT-1000 measurements (r = 0.15). Similarly, pivot-shift tests were related to involved-knee KT-1000 measurements (r = 0.26) but not to side-to-side differences (r = -0.08).


CONCLUSIONS
These results suggest that side-to-side KT-1000 measurements obtained with an anterior translation force of 89 N should not be used in isolation to determine ACL reconstruction success or failure 1 year following surgery.
Tyler
T F
TF
Nicholas Institute of Sports Medicine and Athletic Trauma, Department of Orthopaedics, Lenox Hill Hospital, New York, NY, USA. Tyler@nismat.org
McHugh
M P
MP
Gleim
G W
GW
Nicholas
S J
SJ
D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology* / Q000601:surgery*; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D011446:Prospective Studies; D019651:Plastic Surgery Procedures