Kinematic characteristics of the tibiofemoral joint during a step-up activity
Introduction
Step-up (stair ascending) is one of the most important daily activities, and has been adopted as a closed-kinetic chain exercise in various lower extremity rehabilitation protocols [1], [2]. During a step-up activity, a large knee joint moment could be generated together with a quadriceps-hamstring co-contraction to help stabilize the knee joint [3], [4]. Therefore, a thorough understanding of the knee joint biomechanics during step-up activity is important for optimizing the rehabilitation protocol to enhance its efficacy in treatment of different pathologies of the knee such as osteoarthritis (OA), ACL reconstruction and total knee arthroplasty (TKA) [3], [5].
Few studies have quantitatively reported on the knee joint kinematics during the step-up motion [6], [7], [8]. For example, Gao et al. [9] used motion analysis method to measure the kinematics of ACL deficient and ACL reconstructed knees. Kozanek et al. [7] compared the knee kinematics during the step-up exercise between ACL deficient and intact contralateral knees using a combined dual-fluoroscopic imaging system (DFIS) and MRI-based model. In a recent study by Moro-oka et al. [10], the articular contact patterns of the knee were approximated using the distance mapping between the tibiofemoral articular cartilage surfaces. While these studies have greatly improved our knowledge on knee kinematics during the step-up activities, the different experimental designs and coordinate system selections made it difficult to obtain a systematic understanding of the knee joint kinematics behavior during the step-up activity.
Therefore, the purpose of this study was to measure the kinematic features of the tibiofemoral joint during the step-up activity using the combined DFIS and MRI technique. Specifically, we measured the tibiofemoral articular cartilage contact point locations during a dynamic step-up motion. Furthermore, we measured the femoral condylar motions using two well-known flexion axes, i.e., the transepicondylar axis (TEA) and the geometry center axis (GCA), and calculated the axial tibial rotation based on these two flexion axes [11].
Section snippets
Methods
Twenty-one healthy knees without any history of surgery from 21 subjects were recruited in this study (age, 34.6 ± 10.4 years; gender, 14 males and 7 females; body height, 1.8 ± 0.1 m; body weight, 80.9 ± 18.1 kg) with informed consent. The testing protocol was approved by our institutional review board. A 3-Tesla magnetic resonance machine (MAGNETOM Trio, Siemens, Malvern, PA) was used to scan the knee joint in the sagittal plane with a double-echo water excitation sequence (thickness: 1 mm,
Results
The flexion angles ranged from 54.4 ± 7.1° at initial contact to full extension at the end of the step-up activity. The average time for the activity was 0.8 ± 0.2 s.
Discussion
This study investigated the in vivo articular cartilage contact kinematics on both tibial plateau and femoral condyle surfaces during a functional step-up (stair ascending) activity. The femoral condylar motions were also measured using the TEA and GCA. In general, both medial and lateral contact points moved anteriorly on the tibial articular surfaces along the step-up motion path. The total excursion of the articular contact points was similar on the medial and lateral tibial surfaces.
Conflicts of Interest
The authors have no financial affiliation or involvement with any commercial organization that has a direct financial interest in this manuscript.
Acknowledgements
The authors would like to gratefully acknowledge the financial support of the National Institute of Health (R01 AR055612) and the Department of Orthopaedic Surgery at Massachusetts General Hospital.
References (30)
- et al.
Effects of progressive resistance strength training on knee biomechanics during single leg step-up in persons with mild knee osteoarthritis
Clinical Biomechanics (Bristol, Avon)
(2011) - et al.
Gait characteristics of patients with knee osteoarthritis
Journal of Biomechanics
(2001) - et al.
Kinematic evaluation of the step-up exercise in anterior cruciate ligament deficiency
Clinical Biomechanics (Bristol, Avon)
(2011) - et al.
Stair ascent and descent at different inclinations
Gait and Posture
(2002) - et al.
Three-dimensional joint kinematics of ACL-deficient and ACL-reconstructed knees during stair ascent and descent
Human Movement Science
(2012) - et al.
Sensitivity of the knee joint kinematics calculation to selection of flexion axes
Journal of Biomechanics
(2004) - et al.
Validation of a non-invasive fluoroscopic imaging technique for the measurement of dynamic knee joint motion
Journal of Biomechanics
(2008) Comments on “validation of a non-invasive fluoroscopic imaging technique for the measurement of dynamic knee joint motion”
Journal of Biomechanics
(2008)- et al.
Anteroposterior stability of the knee during the stance phase of gait after anterior cruciate ligament deficiency
Gait and Posture
(2012) - et al.
Tibiofemoral kinematics and condylar motion during the stance phase of gait
Journal of Biomechanics
(2009)