Objective evaluation of anterior knee laxity; comparison of the KT-1000 and GNRB® arthrometers
- 561 Downloads
Accurate measurement of laxity after anterior cruciate ligament (ACL) rupture is usually performed with the KT-1000 arthrometer, and reproducibility and reliability are discussed. A new arthrometer, the GNRB®, has been recently developed in an attempt to improve intra- and inter-examiner reproducibility. The aim of this diagnostic study was to evaluate the intra- and inter-examiner reproducibility of the GNRB® and the KT-1000.
Three protocols were designed to evaluate and compare the two arthrometers. Fifteen physiotherapists conducted tests on 15 subjects with healthy knees. The intra- and inter-reproducibility of the two tests were compared by analysis of variance and the F-test.
Measure reproducibility was significantly worst with the KT-1000 than with the GNRB® (machine effect, P < 0.001) regardless of operator experience. There was no significant difference between experienced and inexperienced examiners with the GNRB® (no ‘examiners effect’). Regardless of the machine, there was a ‘side effect’ with healthy knees.
This clinical study demonstrates the superior intra- and inter-examiner reproducibility of the GNRB® over the KT-1000. There appears to be some technological advantages to using the GNRB® including pressure control of the patella, accuracy of the displacement transducer, control of the load on the calf, and control of hamstring activity.
Level of evidence
Diagnostic study, Level I.
KeywordsArthrometer Laximeter Anterior cruciate ligament rupture KT-1000 GNRB
Conflict of interest
The authors have no potential conflict of interest.
- 1.Ahlden M, Kartus J, Ejerhed L, Karlsson J, Sernert N (2009) Knee laxity measurements after anterior cruciate ligament reconstruction, using either bone-patellartendon-bone or hamstring tendon autografts, with special emphasis on comparison over time. Knee Surg Sports Traumatol Arthrosc 17:1117–1124PubMedCrossRefGoogle Scholar
- 7.Boyer P, Djian P, Christel P, Paoletti X, Degeorges R (2004) Fiabilité de l’arthromètre KT-1000 pour la mesure de la laxité antérieure du genou. Rev Chir Ortho 90:757–764Google Scholar
- 8.Branch TB, Mayr HO, Browne JE, Campbell JC, Stoehr A, Jacobs CA (2010) Instrumented examination of anterior cruciate ligament injuries: minimizing flaws of the manual clinical examination. Arthroscopy 7:997–1004Google Scholar
- 9.Daniel DM, Malcom LL, Losse G, Stone ML, Sachs R, Burks R (1985) Instrumented measurement of anterior laxity of the knee. J Bone Joint Surg 67 A:720–726Google Scholar
- 13.Guskiewitcz KM, Perrin DH, Martin DE, Kahler DM, Gansneder BM, McCue FC (1995) Effects OF ACL reconstruction and tibial rotation on anterior knee laxity. Athl Training 30:243246Google Scholar
- 21.Lerat JL, Moyen B, Cladiere F, Besse JL, Adibi H (2000) Knee instability after injury of the ACL. Quantification of the Lachman test. J Bone Joint Surg 82-B:42–47Google Scholar