Effect of Different Knee Braces in ACL-Deficient Patients

Abstract

Knee braces are often used during rehabilitation after ACL injury. There are two main concepts, rigid and soft braces, but studies comparing the two show conflicting results. Most studies used movement tasks with low translational or rotational loads and did not provide joint kinematics. Therefore, the purpose of this study was to investigate the influence of two different knee braces (rigid vs. soft) on knee joint kinematics in ACL-deficient patients compared to an unbraced control condition using two tasks (walking and 180 • cutting) provoking knee movements in the frontal and transverse planes. 17 subjects with ACL-deficient knees participated in this study. 3D knee joint kinematics were recorded. To provoke frontal plane knee joint motion a laterally tilting plate was applied during a walking task. Both braces reduced the maximum valgus angle compared to the unbraced condition, stabilizing the knee joint against excessive valgus motion. Yet, no differences in peak abduction angle between the two braces were found. However, a significant extension deficit was observed with the rigid brace. Moreover, both braces increased transverse plane RoM and peak internal rotation angle, with the effects being significantly larger with the rigid brace. These effects have been associated with decreased knee stability and unphysiological cartilage loading. Therefore, the soft brace seems to be able to limit peak abduction with a lesser impact on physiological gait compared to the rigid brace. The cutting task was selected to provoke transverse plane knee movement and large external knee rotation was expected. However, none of the braces was able to reduce peak external knee rotation. Again, an increase in transverse plane RoM was observed with both braces. Based on these results, no brace outmatched the other in the second task. This study was the first attempt to clarify the effect of brace design for the stabilization of the knee joint during movements with frontal and transverse plane loading. However, to provide physicians and patients with a comprehensive guideline for brace usage, future studies will have to extent these findings to other daily or sportive movement tasks.

Biomechanical Effects of Prophylactic Knee Bracing on Anterior Cruciate Ligament Injury Risk: A Systematic Review

“…There is a paucity of evidence in the current literature to describe minimal clinically important differences (MCID) values for kinematic and kinematic factors in the reduction of ACL injuries. Focke et al 57 have noted that no previous studies have reported MCID for knee joint kinematics in the coronal and transverse planes during locomotion tasks.…”

Effects of Hip Bracing on Gait Biomechanics, Pain and Function in Subjects With Mild to Moderate Hip Osteoarthritis

“…Application of markers on clothing increases the risk of relative movement between the bony segment and the marker ( Milner, 2008 ). The application of other methods such as clusters, often reported for knee brace analyses ( Focke et al, 2020 ; Turner et al, 2021 ), is not applicable for the hip joint as the pelvis was entirely covered by the brace and adjoining segments (thighs and torso) possess large portions of wobbling mass. However, as the pelvis belt of the brace was fitted very tightly, relative movement between the pelvis and the brace is probably small but cannot be fully excluded.…”

Comparison of outcome following knee immobilization versus no immobilization in the immediate post operative period following arthroscopic anterior cruciate ligament reconstruction

“…Knee braces have traditionally been used in the post-operative period following ACL reconstruction but considerable debate exists in literature regarding its efficacy and rationale of use. 5,6 Graft site protection, limiting varus-valgus stress and reducing post-operative pain are commonly cited reasons for using it while concern for lost of motion is the most common reason for not using it. 3,4 Our study consisted of 60 patients (Mean age 27.27; SD±4.6), randomized into two groups where half of the patients were given a unhinged long extension knee brace immediately post operatively while the other half were not given any bracing.…”

“…Data reported so far is inconclusive regarding the need for knee bracing after ACL reconstruction. 5,6 Purpose of this study is to compare the functional outcome and pain control in patients using knee immobilizer with those not using it in the immediate post-operative period.…”