[The KT 1000 arhtrometer in the comparative study of stability of knee joints operated on for instability].

In 1981 through 1989 authors performed 160 complex reconstruction operations for instability of the knee joint according to the basic principles of W. Müller, striving to restore all structures injured. 92 patients with 378 operations were controlled. The assessment of the results was based on the physical examination, the measurement of ligament laxity with the K 1000 arthrometer, the opinion of the patients, the level of their activity and Lysholm's functional point system was used. The stability of the knee could be restored in 73 per cent of the cases. The patients have thought the knees, found more stable with the arthrometer, really more stable. There was however no unambiguous relation between the knee stability and the level of activity of the patients. The most frequent complaint was pain, increased synovial fluid and the hindrance of squatting. The results were better if the patient had no previous operation in an other department and in those who did not need menisectomy, who had less operations, less body weight and better muscular force.