The Effects of Knee Orthosis with Two Degrees of Freedom Joint Design on Gait and Sit-to-Stand Task in Patients with Medial Knee Osteoarthritis

Abstract

Objectives: Knee bracing as a conservative treatment option for patients with medial knee osteoarthritis (KOA) is of great interest to health practitioners and patients alike. Optimal orthotic knee joint structure is essential to achieve biomechanical and clinical effectiveness. Therefore, this study aimed to identify the effects of a knee orthosis with a new two-degrees-of-freedom (DOF) joint design on selected gait parameters and in a sit-to-stand task in patients with mild-to-moderate medial KOA. Methods: This study was conducted both at the Physical Medicine and Rehabilitation Clinic in Shahid Modarres Academic Hospital and the Biomechanical Laboratory of Rehabilitation Faculty of Iran University of medical Sciences in Tehran, Iran from September 2015 to October 2017. The gait performance of 16 patients was assessed without an orthosis, using a common one-DOF (DOF) knee orthosis and using the same knee orthosis with a two-DOF orthotic joint design. The interactive shearing force between limb and brace in the shell area during a sit-to-stand test was also identified. Repeated measures analysis of variance was used to analyse the data. Results: Compared with walking with no orthosis, both orthosis conditions reduced the external knee adduction moment significantly (P ≤0.05). A significant increase between the one-DOF and two-DOF conditions in terms of walking speed (P = 0.041 and P = 0.009, respectively) and stride length (P = 0.028 and P = 0.038, respectively) was observed. In a sit-to-stand test, wearing the orthosis significantly decreased knee transverse plane range of motion (P ≤0.05). There was a 41.31 ± 8.34 Newtons reduction in knee flexion constraint force. Conclusion: The two-DOF knee orthosis was more comfortable compared to the one-DOF knee orthosis during deep knee flexion. Otherwise, the one- DOF- and two-DOF-braces performed similarly.
 Keywords: Knee Osteoarthritis; Orthosis; Braces; Gait Analysis; Rotations; Kinematics; Kinetics; Patient Comfort.

Biomechanical Effect of Valgus Knee Braces on the Treatment of Medial Gonarthrosis: A Systematic Review

“…Eight studies found that the use of a knee valgus brace significantly improved walking speed, with a maximum increase of 23.53% and a minimum increase of 4.32% [ 26 , 30 – 32 , 35 , 36 , 38 , 39 ]. However, seven studies reported no significant difference in walking speed when patients wore the brace [ 21 , 27 – 29 , 33 , 34 , 37 ], and two of those studies even showed negative effects of valgus braces on walking speed [ 29 , 33 ].…”

“…The distance in one step is called the step length, and the distance between two consecutive heel contacts of the same foot is called the stride length [ 40 ], as described in Figure 4 . Three studies found that the valgus braces were effective in improving step length and stride length in the arthritic limb, with a maximum increase of 16.90% and a minimum increase of 5.66% [ 26 , 30 , 38 ], as shown in Table 2 , whereas six studies showed that the braces had no significant improvement in step length and stride length [ 27 , 33 , 34 , 39 ] and even had a negative effect on step length due to the restriction of range of motion (ROM) in the sagittal plane [ 21 , 31 ].…”

“…Arazpour et al [ 26 ] discovered that knee ROM was decreased by 11.36% after wearing the brace. Fesharaki et al [ 30 ] found a maximum reduction of 25.68% in knee ROM with wearing the brace. Gaasbeek et al [ 31 ] reported that the brace significantly decreased the ROM by 5.45%.…”

“…Three studies described the BAM, which was around 10% of the KAM, and suggested that BAM was associated with valgus angulations or strap tensions [ 25 , 37 , 38 ]. Two studies mentioned that the 2 degree-of-freedom (DOF) brace decreased the external shear force by 41.31 ± 8.34 N compared to the 1-DOF brace when knee joint at 90° flexion states [ 24 , 30 ], as shown in Figure 5(f) .…”

“…Some limitations of the current studies must be noted. First, the knee ROM is significantly recued, which might lead to a reduction in foot clearance and a shorter step length [ 26 , 30 , 31 ]. Second, few studies evaluate the patient compliance.…”