Evaluation of patients with an anterior cruciate ligament rupture, before and after reconstruction, with special emphasis on the use of the KT-1000 arthrometer

Abstract

The aim of the study was to analyse the outcome and function after anterior cruciate ligament(ACL) reconstruction using different evaluation systems. Special emphasis was placed on thesagittal knee laxity as measured with the KT-1000 arthrometer.The patients were operated on using bone-patellar tendon-bone autografts and rehabilitatedaccording to an individual training programme based on standardised accelerated guidelines.The post-operative outcome two years after reconstruction was analysed in 527 patients. TheKT-1000 measurement did not correlate with the subjective, objective and functionalevaluation scores that were used. Four hundred and twenty-nine patients were divided intosubgroups with increased, normal and reduced knee laxity at the post-operative follow-up.Persisting deficits in range of motion (ROM) were found more often in patients with reducedor increased knee laxity. Patients with increased post-operative knee laxity had an inferiorfunctional outcome.The inter- and intra-examiner reproducibility of the KT-1000 arthrometer was analysed. Thereproducibility between two experienced examiners was acceptable and, for the sameexaminer the reproducibility was considered good.In 45 male patients with an ACL injury, the anterior knee laxity had an inverse correlationwith the concentric peak torque (PT) of the hamstring muscles on the injured side.The KT-1000 revealed increased sagittal laxity in a group of patients with a right-sided ACLinjury compared with a group of patients with a left-sided ACL injury pre-operatively andafter ACL reconstruction. The same thing was found in healthy persons.In conclusion, the overall post-operative results after ACL reconstruction using bone-patellartendon-bone autografts were good. The laxity tests cannot be used to predict a return to highlevelactivities or the overall outcome. A persistent deficit in ROM is a common postoperativecomplication after ACL reconstruction. In clinical studies, it is recommended thatthe same examiner should perform the KT-1000 evaluations. The KT-1000 is not useful fordiagnosing an ACL injury in an individual patient. Male patients with strong hamstringmuscles displayed less anterior knee laxity in the ACL injured side compared with malepatients with weak hamstring muscles. It appears to be important to report the laxity andfunctional outcome of right and left knees separately, in studies reporting the results afterACL reconstruction.