Effect of partial medial meniscectomy on anterior tibial translation in stable knees: a prospective controlled study on 32 patients

BACKGROUND: Quantitative measurement of anterior translation of the tibia (ATT) by KT 1000 is used mainly to provide an objective assessment of knee laxity after anterior cruciate ligament (ACL) tears or ACL reconstructions. Only few papers described its use after menisectomies in knees with intact ACL. The objective of this paper is to determine whether partial medial meniscectomies could induce significant immediate post-operative ATT. METHODS: Thirty-two patients with a diagnosis of partial medial meniscal tear limited to the posterior horn and documented with magnetic resonance imaging (MRI) were assessed under anesthesia before and immediately after arthroscopic meniscectomy. The assessment was performed by the same examiner by means of the MEDmetric(R) KT-1000 instrument using manual maximum (MM) force. The opposite knees were also assessed. RESULTS: There is a significant difference between pre and post-operative KT MM mean values for the operated knees (CI: -3.933953 to −2.947297, p < 0.0001). No significance was found between the mean values for the contralateral knees before and after the completion of the menisectomy on the operated knees (p = 0.4). For the operated knees, 14 (43.75%) had a side-to-side difference between pre-and post-operative values of more than 3 mm, whereas for the contralateral knees, only 2 (6%) had the same. CONCLUSION: Less than half of operated knees showed significant side-to-side difference values of ATT (>3 mm), immediately after meniscectomies in unconscious patients. Our values might reflect a temporarily increase of anterior laxity under specific conditions but whether a significant laxity remains in some knees, such changes may lead to higher cartilage loading and early osteoarthritis.