Dynamically tensioned ACL functional knee braces reduce ACL and meniscal strain
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The effectiveness of ACL functional knee braces to reduce meniscal and ACL strain after ACL injury or reconstruction is not well understood. A new dynamic knee tensioning brace system has been designed to apply an active stabilizing force to the knee. The ability of this system to reduce tissue strains is unknown. The purpose of this study was to test the ability of the dynamically tensioned brace to reduce strain in both the ACL and meniscus during rehabilitation activities.
A combined in vivo/in silico/in vitro method was used to study three activities: gait, double leg squat, and single leg squat. Muscle forces and kinematics for each activity were derived through in vivo motion capture and applied to seven cadaveric knee specimens fitted with custom braces. Medial meniscal strain and ACL strain were measured in ACL intact, deficient and reconstructed conditions.
The brace lowered peak and average meniscal strain in ACL deficient knees (P < 0.05) by an average of 1.7%. The brace was also found to lower meniscal strain in reconstructed knees (1.1%) and lower ACL strain in ACL intact (1.3%) and reconstructed knees (1.4%) (P < 0.05).
This study supports the use of a brace equipped with a dynamic tensioning system to lower meniscal strain in ACL-deficient knees. Its use may help decrease the risk of subsequent meniscal tears in chronic ACL deficiency or delayed reconstruction. In ACL-intact and reconstructed knees, the brace may be beneficial in injury prophylaxis or in protecting the ACL graft following reconstruction. These results will aid clinicians make informed recommendations for functional brace use in patients with unstable knees.
Level of evidence
KeywordsFunctional brace Meniscus strain Knee biomechanics ACL reconstruction
Anterior cruciate ligament
Anterior tibial translation
Double leg squat
Dynamic tensioning system
Differential variable reluctance transducer
Functional knee brace
Single leg squat
This work was supported by a grant from Ossur Inc. One of the authors is an employee of Ossur Inc.
ST was involved in all phases of the research project. RB was involved in all phases of the research project. DW was involved in study design, in vitro testing and paper writing/editing. MK was involved in in vitro testing and paper writing/editing. MN, was the industrial connection and involved in study proposal, brace procurement, and paper writing/editing. CW was involved in all phases of the research project. NC was involved in all phases of the research project.
Compliance with ethical standards
Conflict of interest
Authors ST and NC have received research grant support from Ossur Inc. Authors ST, RB, MK, NC are affiliated with the institution that received the grant. Author MN is an employee of Ossur Americas.
This study was funded by Ossur Inc (Grant no. RA060075).
This study was approved by the University of Waterloo Office of Research Ethics (ID# T1504-1).
Informed consent was obtained from all participants included in the study.
Supplementary material 1 (MP4 7153 KB)
- 15.Fleming BC, Renstrom PA, Beynnon BD, Engstrom B, Peura GD, Johnson RJ, Peura GD, Nichols CE, Pope MH (2000) The influence of functional knee bracing on the anterior cruciate ligament strain biomechanics in weightbearing and nonweightbearing knees. Am J Sports Med 28:815–824CrossRefPubMedGoogle Scholar
- 30.Mishra DK, Daniel DM, Stone ML (1989) The use of functional knee braces in the control of pathologic anterior knee laxity. Clin Orthop Relat Res 241:213–220Google Scholar