|
March 2006 • Vol. 2, No. 1
|
Advancing Orthotic and Prosthetic
Care Through Knowledge
|
Aaron A. Rasmussen, NCOPE Orthotist
Keith M. Smith, CO, LO
Regaining efficient ambulation following a spinal cord injury (SCI) can prove to be a difficult task, not only because of the
paresis or paralysis, but also because of the limited orthotic options that have been available. The level and severity of the neurologic lesion are the main factors influencing the extent to which walking will be a practical means of mobility. Individuals with a lesion at level C7 or above do not typically have the muscle involvement necessary for ambulation. Individuals with lesion level T1 – T12 may fall in the category of using a reciprocating gait orthosis (RGO) or hip-knee-anklefoot orthosis (HKAFO) depending on the resultant muscle strengths.1 In the past, knee-ankle-foot orthoses (KAFOs) have proved to be of limited functional value for individuals with a spinal lesion of T12 and above and have frequently been abandoned.2 Departure from the use of KAFOs for these individuals was due greatly to insufficient hip, pelvic, and trunk support, as well as a lack of hip flexion assistance. However, some experts report that the HKAFO provides insufficient support, offering upright posture only.3 Additionally, the pivotal or swing-through gait results in high energy expenditure.
Rose suggests that some form of hip and trunk control while taking a step is necessary.4 The RGO was developed in 1967 to reduce high energy expenditure and to allow for a reciprocal gait pattern where hip flexion on one side would cause hip extension on the contralateral side.1 The isocentric RGO (IRGO), introduced by Wally Motloch in 1991, differs from other RGOs in that the two hip joints are no longer connected by cables, greatly reducing the friction on the system. In place of the cables, a pelvic band pivots a central point connecting the two hip joints. Although the mechanics of the RGO were updated, a major limitation still exists. The patient must ambulate with fixed knees, which has been shown by Mattsson and Brostrom to cause an increase in oxygen uptake by up to 23 percent per limb.5 Compensation for a locked knee gait pattern is a lateral lean or vault to clear the swinging limb from the ground. Because the hip and knee cannot flex, these compensations become necessary for initiation of gait and clearance of the swinging limb. In addition, the patient is forced to use considerable upper body strength and, therefore, exert even greater energy to assist with the vaulting and clearance of the swinging limb.6 Several studies have cited a need for compensatory motion.7-9 McMillan et al. cite numerous studies that have shown that a fixed knee is less energy efficient and, therefore, limits the distance a patient can ambulate before becoming fatigued.7 The development of the stance control orthosis (SCO) addressed the need for an orthosis that could solve these problems and opened up a whole new era of rehabilitation for patients with paralysis of the lower limb(s).
The use of the SCO provides necessary knee stability during stance phase while allowing free motion during the swing phase of the gait cycle.7-9 In support of the SCO, Hebert and Liggins showed elimination of vaulting as well as vertical excursion and a trend towards improved energy efficiency.9 Kaufman et al. showed a decrease in oxygen consumption and energy cost in a KAFO with free knee motion in swing.8 Drawing from these findings, this case study takes the idea of the SCO and applies it to that of the RGO. The purpose of this study was to determine if an RGO with stance control capabilities could enable an individual with lower limb paralysis to ambulate more efficiently than when using the traditional RGO with fixed knees.
The patient is a victim of a motor vehicle accident with a resultant T10 complete spinal cord injury with grade zero strength
at the hips, knees, and ankles. The patient was originally fit with an IRGO with drop lock knee joints attached to carbon
fiber laminated AFOs with bilateral condylar extensions and pre-tibial shells made of 1/8 inch copolymer and polyethylene foam. The right side of the RGO was replaced with a stance control KAFO (Horton stance control KAFO), with medial and lateral stance control joints. The joints allow for three settings: locked, unlocked, and stance control. The ankles were fixed at 90 degrees. Two months later, a second stance control KAFO was added to the RGO on the left side, which also had medial and lateral stance control joints.
The patient ambulated in the original RGO with a posterolateral lean due to the inability to initiate swing effectively. Innormal gait, hip and knee flexion shortens the leg length, allowing for easy clearance of this ipsilateral limb. With a fixed
knee, however, hip and knee flexion is absent causing the patient to lean to one side to unweight the contralateral limb to
initiate gait. The patient has considerable upper body strength and could, therefore, ambulate by raising himself on his walker
to unweight the legs (Figure 1). This led to quick fatigue as the lift and lateral lean soon became the replacement for his
absent hip and knee flexion.
|
|
Figure 1: Patient compensating by vaulting or lifting his body to clear the limb.
|
Figure 2: Due to swing knee flexion the foot clears the ground without catching.
|
The question was proposed as to whether allowing one leg to bend with resultant hip and knee flexion in gait would allow for a more posterior lean in swing phase. After application of the stance control KAFO to the right side, it became immediately evident that the patient could ambulate more quickly and efficiently. Subsequently, the patient reported that it took less effort to initiate a step and there was no catching of his foot on the ground as it swung through swing phase (Figure 2).
The contralateral side, however, was still catching the ground periodically during its swing phase cycles and a lateral lean to the contralateral side was necessary to clear the leg. After the attachment of the second stance control KAFO, the patient immediately had a gait pattern with bilateral hip and knee flexion in swing phase. As shown in Figure 3, there was no longer a need for lateral lean or for using the upper extremities to lift the body to clear the foot.
|
Figure 3a and b: There is no need for compensatory lateral lean or vaulting with
bilateral stance control KAFOs.
|
The patient is currently participating in gait study trials to determine the efficacy of the Stance Control Reciprocating Gait Orthosis, quantitatively. The focus of this research is on comparing the biomechanical advantages and disadvantages of fixed swing phase knee joints versus free swing phase or stance control joints.
Scivoletto G, Petrelli A, Lucente LD, Giannantoni A, Fuoco U, D’Ambrosio F, Filippini V. One year
follow up of spinal cord injury patients using a reciprocating gait orthosis: preliminary report.
Spinal Cord. 2000 Sep;38(9):555-8. Middleton JW, Sinclair PJ, Smith RM, Davis GM. Postural control during stance in paraplegia:
effects of medially linked versus unlinked knee-ankle-foot orthoses. Arch Phys Med Rehabil.
1999 Dec;80(12):1558-65. Campbell JH. Outcome Study: The progression of spinal deformity in paraplegic children fitted
with reciprocating gait orthoses. J Prosthet Orthot. 1999;11(4):79-89. Rose GK. The principles and practice of hip guidance articulations. Prosthet Orthot Int.
1979;3:37-43. Mattsson E, Brostrom L-A. The increase in energy cost of walking with an immobilized knee or
an unstable ankle. Scand J Rehab Med. 1990;22:51-3. Waters RL, Yakura JS, Adkins R, Barnes G. Determinants of gait performance following spinal
cord injury. Arch Phys Med Rehabil. 1989 Nov;70(12):811-8. McMillan AG, Kendrick K, Michael JW, Aronson J, Horton GW. Preliminary evidence for
effectiveness of a stance control orthosis. J Prosthet Orthot. 2004;16(1):6-13. Kaufman KR, Irby SE, Mathewson JW, Wirta RW, Sutherland DH. Energy-efficient knee-anklefoot
orthosis: a case study. J Prosth Orthot. 1996;8(3):79-85. Hebert JS, Liggins AB. Gait evaluation of an automatic stance-control knee orthosis in a patient
with postpoliomyelitis. Arch Phys Med Rehabil. 2005 Aug;86(8):1676-80.
Special thanks to Gary Horton and Horton Orthotic Lab for the fabrication of the Stance Control KAFOs implemented with this patient.
Take the quiz at the Academy's Online Learning Center.
|
|
