Quantitative gait analysis of patients with unilateral juvenile osteochondritis dissecans of the knee: Comparison with the contralateral side and controls

Abstract

Juvenile osteochondritis dissecans (JOCD) of the knee is a common cause of pain and dysfunction among active children and adolescents [1,2]. JOCD is defined as a pathologic process for which the blood supply to a bone area is disrupted due to excessive loading forces on some parts of the joint, causing the necrosis of the subchondral bone and cartilage [3–5]. In youths with stable JOCD of the knee, conservative management focusing on biomechanical factors and unloading is the standard of care [6]. However, it is not clear how the biomechanical factors, such as the lower limbs kinematics and kinetics during walking, are associated with JOCD [6]. The aim of this project was to identify objective biomechanical outcomes associated with JOCD to better target conservative treatment options. Thirteen (n=13) patients with unilateral medial femoral condyle JOCD and nineteen (n=19) control subjects were evaluated at the SHC-Canada. Three distinct groups were created for comparison: 1) JOCD side, 2) Unaffected contralateral side, 3) Healthy controls. JOCD patients were evaluated before conservative treatment initiation. All participants performed barefoot overground walking at a self-selected speed. Retroreflective markers were placed on specific bony landmarks according to the Plug-In-Gait marker set [7]. A 10-camera motion capture system (VICON) with 4 forceplates (AMTI) were used to collect kinematic and kinetic data. Joint angles and moments at the hip and knee was processed using Nexus 2.12.1 and averaged for three complete gait cycles. For the main outcome measures, peak joint angle and moment in the coronal plane were outputted at the hip and knee. To identify statistical differences between groups (α=0.05), the main outcome measures were compared using paired t-test between JOCD and unaffected groups, and unpaired t-test between JOCD and control groups. Data showed altered knee joint movement patterns for the JOCD side group, with significantly higher peak knee varus angle (vs. unaffected=+2.66°, p=0.002; vs. controls=+2.39°, p=0.02) and varus-thrust angle (vs. unaffected=+1.48°, p=0.02) (Fig. 1B). Data also showed altered kinetics for the JOCD side group, with significantly lower peak hip adduction moment (vs. controls=-0.19 N∙m/kg, p=0.001) and peak knee adduction moment (vs. controls=-0.12 N∙m/kg; p=0.02) (Fig. 1C&D).Download : Download high-res image (116KB)Download : Download full-size image Higher knee motion in the coronal plane for youths with JOCD suggest the presence of medio-lateral knee instability. Also, reduced knee adduction moment in the presence of JOCD suggest compensations at the ipsilateral trunk and hip to reduce medial femoral condyle loading. Potential treatment focusing on knee medio-lateral stability, such as motor control exercises and knee unloading brace, have potential at improving neutral dynamic knee alignment during walking. The current set of data will serve as a method to develop a standardized conservative protocol focusing on objective biomechanical outcomes to improve JOCD patient’s quality of care and treatment success rate.