Biomechanical response to ankle-foot orthosis stiffness during running.

BACKGROUND The Intrepid Dynamic Exoskeletal Orthosis (IDEO) is an ankle-foot orthosis developed to address the high rates of delayed amputation in the military. Its use has enabled many wounded Service Members to run again. During running, stiffness is thought to influence an orthosis' energy storage and return mechanical properties. This study examined the effect of orthosis stiffness on running biomechanics in patients with lower limb impairments who had undergone unilateral limb salvage. METHODS Ten patients with lower limb impairments underwent gait analysis at a self-selected running velocity. 1. Nominal (clinically-prescribed), 2. Stiff (20% stiffer than nominal), and 3. Compliant (20% less stiff than nominal) ankle-foot orthosis stiffnesses were tested. FINDINGS Ankle joint stiffness was greatest in the stiffest strut and lowest in the compliant strut, however ankle mechanical work remained unchanged. Speed, stride length, cycle time, joint angles, moments, powers, and ground reaction forces were not significantly different among stiffness conditions. Ankle joint kinematics and ankle, knee and hip kinetics were different between limbs. Ankle power, in particular, was lower in the injured limb. INTERPRETATION Ankle-foot orthosis stiffness affected ankle joint stiffness but did not influence other biomechanical parameters of running in individuals with unilateral limb salvage. Foot strike asymmetries may have influenced the kinetics of running. Therefore, a range of stiffness may be clinically appropriate when prescribing ankle-foot orthoses for active individuals with limb salvage.

[1]  Daan J J Bregman,et al.  Studies Examining the Efficacy of Ankle Foot Orthoses should Report Activity Level and Mechanical Evidence , 2010, Prosthetics and orthotics international.

[2]  Elena M Gutierrez-Farewik,et al.  Effects of carbon fibre spring orthoses on gait in ambulatory children with motor disorders and plantarflexor weakness , 2007, Developmental medicine and child neurology.

[3]  B. Nigg,et al.  The effect of an ankle orthosis on ankle range of motion and performance. , 1996, The Journal of orthopaedic and sports physical therapy.

[4]  Johnny G Owens,et al.  Physical therapy of the patient with foot and ankle injuries sustained in combat. , 2010, Foot and ankle clinics.

[5]  Kaat Desloovere,et al.  How can push-off be preserved during use of an ankle foot orthosis in children with hemiplegia? A prospective controlled study. , 2006, Gait & posture.

[6]  Joseph C Wenke,et al.  Comparative effect of orthosis design on functional performance. , 2012, The Journal of bone and joint surgery. American volume.

[7]  Arthur D Kuo,et al.  Energetics of actively powered locomotion using the simplest walking model. , 2002, Journal of biomechanical engineering.

[8]  R. Grimer,et al.  Quality of Life Implications as a Consequence of Surgery: Limb Salvage, Primary and Secondary Amputation , 2001, Sarcoma.

[9]  J. Hamill,et al.  Shock attenuation and stride frequency during running , 1995 .

[10]  Y Suzuki,et al.  Stiffness control in posterior-type plastic ankle-foot orthoses: Effect of ankle trimline Part 1: A device for measuring ankle moment , 1996, Prosthetics and orthotics international.

[11]  C. T. Farley,et al.  Leg stiffness primarily depends on ankle stiffness during human hopping. , 1999, Journal of biomechanics.

[12]  John F Kragh,et al.  Combat wounds in operation Iraqi Freedom and operation Enduring Freedom. , 2008, The Journal of trauma.

[13]  R. Emmerik,et al.  A dynamical systems approach to lower extremity running injuries. , 1999, Clinical biomechanics.

[14]  M. Schwellnus,et al.  A Fivefold Reduction in the Incidence of Recurrent Ankle Sprains in Soccer Players Using the Sport-Stirrup Orthosis , 1994, The American journal of sports medicine.

[15]  John F Kragh,et al.  Characterization of Extremity Wounds in Operation Iraqi Freedom and Operation Enduring Freedom , 2007, Journal of orthopaedic trauma.

[16]  S. Hillman,et al.  Comparison of support provided by a semirigid orthosis and adhesive ankle taping before, during, and after exercise , 1990, The American journal of sports medicine.

[17]  O. Rettig,et al.  Dynamic assist by carbon fiber spring AFOs for patients with myelomeningocele. , 2008, Gait & posture.

[18]  R. Major,et al.  A new structural concept in moulded fixed ankle foot orthoses and comparison of the bending stiffness of four constructions , 2004, Prosthetics and orthotics international.

[19]  J. Lehmann,et al.  Gait abnormalities in hemiplegia: their correction by ankle-foot orthoses. , 1987, Archives of physical medicine and rehabilitation.

[20]  Joseph R Hsu,et al.  How Does Ankle-foot Orthosis Stiffness Affect Gait in Patients With Lower Limb Salvage? , 2014, Clinical orthopaedics and related research.

[21]  Joseph R Hsu,et al.  Return to running and sports participation after limb salvage. , 2011, The Journal of trauma.

[22]  Richard R Neptune,et al.  Selective laser sintered versus carbon fiber passive-dynamic ankle-foot orthoses: a comparison of patient walking performance. , 2014, Journal of biomechanical engineering.

[23]  Clare E. Milner,et al.  Biomechanical factors associated with tibial stress fracture in female runners. , 2006, Medicine and science in sports and exercise.

[24]  R. Waters,et al.  The energy expenditure of normal and pathologic gait. , 1999, Gait & posture.

[25]  H. Houdijk,et al.  Polypropylene Ankle Foot Orthoses to Overcome Drop-Foot Gait in Central Neurological Patients: A Mechanical and Functional Evaluation , 2010, Prosthetics and orthotics international.

[26]  L Claes,et al.  Gait Asymmetry Following Successful Surgical Treatment of Ankle Fractures in Young Adults , 1995, Clinical orthopaedics and related research.

[27]  J. Wilken,et al.  Reliability and Minimal Detectible Change values for gait kinematics and kinetics in healthy adults. , 2012, Gait & posture.

[28]  Richard R Neptune,et al.  Optimization of prosthetic foot stiffness to reduce metabolic cost and intact knee loading during below-knee amputee walking: a theoretical study. , 2012, Journal of biomechanical engineering.

[29]  Daniel P. Ferris,et al.  Walking with increased ankle pushoff decreases hip muscle moments. , 2008, Journal of biomechanics.

[30]  M. Latash,et al.  Joint stiffness: Myth or reality? , 1993 .

[31]  T. A. Greene,et al.  A comparative support evaluation of three ankle orthoses before, during, and after exercise. , 1990, The Journal of orthopaedic and sports physical therapy.

[32]  Roman A Hayda,et al.  The Military Extremity Trauma Amputation/Limb Salvage (METALS) study: outcomes of amputation versus limb salvage following major lower-extremity trauma. , 2013, The Journal of bone and joint surgery. American volume.

[33]  Sumiko Yamamoto,et al.  Development of an Ankle-Foot Orthosis with Dorsiflexion Assist, Part 2 , 1999 .

[34]  S. Collins,et al.  The effect of ankle foot orthosis stiffness on the energy cost of walking: a simulation study. , 2011, Clinical biomechanics.

[35]  Y Suzuki,et al.  Stiffness control in posterior-type plastic ankle-foot orthoses: Effect of ankle trimline Part 2: Orthosis characteristics and orthosis/patient matching , 1996, Prosthetics and orthotics international.

[36]  A. Bhave,et al.  Improvement in gait parameters after lengthening for the treatment of limb-length discrepancy. , 1999, The Journal of bone and joint surgery. American volume.

[37]  Nicholas P. Fey,et al.  Altering prosthetic foot stiffness influences foot and muscle function during below-knee amputee walking: a modeling and simulation analysis. , 2013, Journal of biomechanics.

[38]  T. McMahon,et al.  The mechanics of running: how does stiffness couple with speed? , 1990, Journal of biomechanics.

[39]  H. P. Crowell,et al.  Lower extremity stiffness: implications for performance and injury. , 2003, Clinical biomechanics.

[40]  R M Rose,et al.  Effect of repetitive impulsive loading on the knee joints of rabbits. , 1978, Clinical orthopaedics and related research.

[41]  Jason M. Wilken,et al.  Can an Integrated Orthotic and Rehabilitation Program Decrease Pain and Improve Function After Lower Extremity Trauma? , 2014, Clinical orthopaedics and related research.

[42]  R. Kloiber,et al.  Bone Mass, External Loads, and Stress Fracture in Female Runners , 1991 .

[43]  Benno M Nigg,et al.  Dynamic Angular Stiffness of the Ankle Joint during Running and Sprinting. , 1998, Journal of applied biomechanics.

[44]  Daniel P Ferris,et al.  Neuromechanical adaptation to hopping with an elastic ankle-foot orthosis. , 2006, Journal of applied physiology.

[45]  Kristin R Archer,et al.  Evidence of beneficial effect of physical therapy after lower-extremity trauma. , 2008, Archives of physical medicine and rehabilitation.

[46]  M. Swiontkowski,et al.  Functional outcomes following trauma-related lower-extremity amputation. , 2004, The Journal of bone and joint surgery. American volume.

[47]  Ewald M. Hennig,et al.  Relationships between Ground Reaction Force and Tibial Bone Acceleration Parameters , 1991 .

[48]  James F Kellam,et al.  An analysis of outcomes of reconstruction or amputation after leg-threatening injuries. , 2002, The New England journal of medicine.

[49]  S. Collins,et al.  Recycling Energy to Restore Impaired Ankle Function during Human Walking , 2010, PloS one.

[50]  J. Hsu,et al.  Volumetric Muscle Loss , 2011, The Journal of the American Academy of Orthopaedic Surgeons.

[51]  Elena M Gutierrez-Farewik,et al.  A new carbon fibre spring orthosis for children with plantarflexor weakness. , 2007, Gait & posture.

[52]  James R Ficke,et al.  The mangled foot and leg: salvage versus amputation. , 2010, Foot and ankle clinics.

[53]  P. Komi,et al.  Gait asymmetry in patients with limb length discrepancy , 2004, Scandinavian journal of medicine & science in sports.

[54]  S. Nadeau,et al.  Plantarflexor weakness as a limiting factor of gait speed in stroke subjects and the compensating role of hip flexors. , 1999, Clinical biomechanics.