Design and validation of an unconstrained loading system to measure the envelope of motion in the rabbit knee joint

Citation
Ad. Milne et al., Design and validation of an unconstrained loading system to measure the envelope of motion in the rabbit knee joint, J BIOMECH E, 123(4), 2001, pp. 347-354
Citations number
39
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Multidisciplinary
Journal title
JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME
ISSN journal
0148-0731 → ACNP
Volume
123
Issue
4
Year of publication
2001
Pages
347 - 354
Database
ISI
SICI code
0148-0731(200108)123:4<347:DAVOAU>2.0.ZU;2-I
Abstract
An unconstrained loading system was developed to measure the passive envelo pe of joint motion in an animal model commonly used to study ligament heali ng and joint arthritis. The design of the five-degree-of-freedom system all owed for unconstrained knee joint loading throughout flexion with repeated removal and reapplication of the device to a specimen. Seven New Zealand Wh ite rabbit knees it-ere subjected to varus, valgus, internal and external l oads, and the resulting envelopes of motion were recorded using an electrom agnetic tracking device. Intra-specimen reproducibility was excellent when measured in one specimen, with maximal rotational differences of 0.6 and 0. 3 deg between the fourth and fifth testing cycles for the varus (VR) and va lgus (VL) envelopes, respectively. Similarly, the maximal internal (INT) an d external (EXT) envelope differences were 0.5 and 0.4 deg, respectively, b etween the fourth and fifth cycles. Good inter-animal envelope reproducibil ity was also observed with consistent motion pathways for each loading cond ition. A maximal VR-VL laxity of 17.9+/-2.3 deg was recorded at 95 deg flex ion for the seven knees tested. The maximal INT-EXT laxity of 75.2+/-4.8 de g occurred at 50 deg flexion. Studies on measurement reproducibility of re- applying individual testing components demonstrated a maximal error of 1.2/-0.7 deg. Serial removal and re-application (test-retest) of the complete measuring system to one cadaveric knee demonstrated maximal envelope differ ences of less than 0.7 deg for VR-VL rotation and 2.1 deg for INT-EXT rotat ion. Our results demonstrate that the measuring system is reproducible and capable of accurate evaluation of knee joint motion. Baseline in vitro data were generated on normal joint kinematics for future in-vivo studies with this system, evaluating ligament healing and disease progression in arthrit is models.