Richards, Amber MPT, PCS; Morcos, Sally DPT, PCS; Rethlefsen, Susan PT; Ryan, Deidre MD
Children with spina bifida (SB), depending on the level of their lesion, vary widely in their presentation, with a host of congenital and acquired orthopedic deformities involving the lower extremities.1 Many children present with hip dislocations, knee valgus deformity, and foot deformities due to muscle imbalance and joint laxity. Some of the more common deformities are rotational deformities of the lower extremities, including internal tibial torsion.2 This can be due to muscle imbalance in the hamstrings or a bony deformity and contributes to in-toeing during gait. Orthopedic surgical intervention and bracing are commonly used to correct these deformities, with consideration for the level of neurological impairment. Lower extremity bracing is used to support or maintain alignment, facilitate function, and maximize mobility in children with SB who are ambulatory. Bracing is a conservative management approach, which is often used to postpone surgical intervention until the child has reached at least 6 years of age.1 Without correction of tibial torsion, gait can become more difficult and painful as the child becomes an adolescent.3
Solid ankle-foot orthoses (AFOs) are braces that are used to address weakness in musculature below the knee in children with sacral or low lumbar level lesions. When internal tibial torsion is present in addition to weakness, twister cables (TCs) attached to AFOs are often used to help control in-toeing. The primary function of TCs is to achieve a more neutral lower extremity alignment through rotation of the lower leg with respect to the thigh, but they do not physically affect the bony deformity.2 Torsional deformities have been associated with knee joint pain in adults with myelomeningocele.3,4 Twister cables are designed to decrease rotational stress imposed by such torsional deformities on the knee joint, which can contribute to knee injuries and pain as well as degenerative changes as children grow in height and weight.4 The use of TCs has been the standard of care in the United States for in-toeing in children with myelomeningocele.1 The current trend of treatment for children with SB has shifted from preventing and correcting lower extremity deformities to maximizing mobility and independence.1 TheraTogs have recently become popular for management of lower extremity alignment problems in children.5,6 TheraTogs are an orthotic undergarment fabricated from Delta-flex, which is a lightweight, breathable fabric that is Velcro-sensitive. It was developed to provide a gentle, passive force to correct imbalance or alignment through the combination of a trunk and a shorts system along with customized, flexible external strapping.5 This garment is worn under clothing for complete contact with the skin over the structures it affects. According to the developers of TheraTogs, the garments provide hip and trunk stability for improved posture, while correcting malalignment in the lower extremities.7
Researchers have shown TheraTogs to be effective in the correction of postural alignment, resulting in improvement in gait characteristics.5,6,8 Previous studies of children with cerebral palsy (CP) using full-body lycra garments worn 6 hours per day for 6 weeks suggested improvement in proximal stability and mobility in some children, as measured by variability of pelvic movement during gait, and the Pediatric Evaluation of Disability Index.6 A study evaluating short-term intensive use of individualized TheraTogs by children with CP (GMFCS level I) reported improvements in gait, balance, and functional skills, as measured by gait analysis, the Bruininks-Oseretsky Test of Motor Proficiency, and the Canadian Occupational Performance Measure.5 Another study involving adults who had a history of stroke showed increased electromyographic activity in gluteus medius and improved gait speed as compared with baseline related to the correction of postural alignment.8 Currently, studies investigating the effectiveness of TheraTogs in children have been primarily directed toward the CP population. The findings from these studies cannot be generalized to the SB population due to the vast difference in clinical presentation.
Anecdotal evidence suggests that both AFOs with TCs and TheraTogs may decrease in-toeing. However, no current data are available to compare the effectiveness of the 2 methods, or to assess the source of alignment correction with TCs and TheraTogs in children with SB. Therefore, the purpose of this case report was an initial attempt to determine whether TheraTogs are as effective as TCs in correcting in-toeing caused by internal tibial torsion in a child with SB while also comparing overall parent and patient satisfaction.
DESCRIPTION OF THE CASE
The participant was a 2-year-old girl with L4 SB who was independent in community ambulation with bilateral in-toeing. The participant's history includes closure of a myelomeningocele and a ventriculoperitoneal shunt placement. She began walking at 12 months of age with parent report of falling 5 to 8 times a day without her braces. At the time of this intervention, she ambulated with bilateral solid AFOs set in neutral without an assistive device. She was independent with all transfers and transitions, while requiring 1 hand-held assist and use of a handrail to negotiate stairs. She presented with activation of all lower extremity musculature with the exception of the plantar flexors and posterior tibialis bilaterally. Formal measurements through manual muscle testing could not be obtained at that time because of the participant's age. Therefore, muscle function was assessed through observation of voluntary movements. Range of motion of both lower extremities was within functional limits. She presented to physical therapy with thigh-foot rotation angles of 15˚ internal on the left and 10˚ internal on the right. Hip internal rotation measured 30˚ bilaterally and hip external rotation measured 30˚ bilaterally, indicating that femoral anteversion was within normal limits.9 The participant had been cleared by the orthopedist to wear the TheraTog suit. She had no prior orthopedic surgeries or interventions other than lower extremity bracing. At the time of the study, the participant was being followed by a physical therapist for monthly monitoring. The participant's mother provided consent for participation in this intervention.
DESCRIPTION OF INTERVENTION
The intervention consisted of two 6-week interventions, 1 of TheraTog (TheraTogs Inc, Telluride, Colorado) (Figure 1) use and 1 of TC (Figure 2) use, with a 90-minute gait analysis test after each 6-week interval. The first gait analysis included baseline measurements with AFOs only followed by TheraTogs and AFOs. The second gait analysis included TCs and AFOs. The parent was trained in the application of a TheraTog garment system that included the hipster piece and flexible lower extremity strapping to promote lower extremity external rotation as described in the TheraTog application manual.7 The patient wore TheraTogs and TCs for 6 weeks each, with instructions to wear the device for 8 to 10 hours a day in combination with her AFOs. The mother kept a log of hours spent wearing each device.
The patient underwent 2 separate 3-dimensional gait analyses in a motion analysis laboratory. The kinematic data were acquired using an 8-camera Vicon 612 (Vicon, Oxford, United Kingdom) 3-dimensional motion analysis system. Data were filtered and processed using Vicon Workstation software (version 5.2.9), with averaged graphs generated using Vicon Polygon software (version 3.1). The Vicon system uses a set of reflective markers affixed to the skin over specific bony landmarks of the pelvis and lower extremities. Kinematic markers were fixed with double-sided tape and placed bilaterally over the anterior superior iliac spine, the point midway between the 2 posterior superior iliac spines, the lateral epicondyle of the femur, lateral shank, lateral malleolus, and heel, and between the distal second and third metatarsal head. Markers were placed as accurately as possible to minimize interference from the TheraTog garment or the pelvic strap of the TCs. When necessary, locations of the pelvic bony landmarks were palpated and markers were placed in the approximate locations on the outside of the garment. An experienced motion laboratory physical therapist (19 years in this motion laboratory) applied the markers, obtained measurements, and reviewed the gait data for both tests. The patient took several walks at a self-selected speed, down a 15-m path with 1 hand-held by the parent, because of her young age and limited attention to the task. Sagittal, coronal, and transverse plane joint motion data were collected for the pelvis, hips, knees, and ankles. Data from 7 to 10 strides for each side under each condition were averaged and used in the gait analysis report. The computerized analysis was completed by the Motion Analysis Laboratory biomedical engineer.
At the end of each intervention trial, the parent submitted the wearing log to the therapist and completed a parent satisfaction survey that had been used in a previous TheraTog study.5 This survey uses a 5-point Likert Scale to document the parent's overall satisfaction with the ease of use and perception of effectiveness of either TheraTogs or TCs.
DESCRIPTION OF OUTCOMES
As this report involved a single case, the data collected were interpreted for clinical significance rather than statistical significance. Although 3-dimensional data were obtained from all joints, the kinematic gait parameters that were examined for this particular report included average foot progression in stance, maximum knee extension in stance, and average hip rotation in stance (Table 1). Hip rotation and foot progression were selected since they were the parameters that should be directly affected by the orthoses. Knee extension in stance was also selected because it showed marked differences between conditions.
At baseline with AFOs alone, the participant exhibited slight knee flexion bilaterally during stance with the right lower extremity greater than the left by 8˚. Hip external rotation was observed bilaterally with the right greater than with the left. Internal foot progression was noted bilaterally in the stance phase of gait, more on the left than on the right (Table 1).
During ambulation with TheraTogs and AFOs, knee flexion in stance was increased to an excessive amount bilaterally. Hip external rotation was increased bilaterally, especially on the left lower extremity. The participant demonstrated more external foot progression than normal on the right lower extremity, while decreasing internal foot progression of the left lower extremity compared with the baseline AFO condition (Table 1).
The greatest changes in kinematic data from the baseline condition were seen during gait with TCs and AFOs. With the TCs, the participant had knee extension values approximating the typical reference standard (RS) bilaterally. The hips remained in external rotation during stance with TCs, but values were less than those with TheraTogs. The patient had increased right external foot progression (closer to the RS value) in comparison to ambulation with AFOs alone; however, this was less than with TheraTogs and AFOs. In the left lower extremity, there was a greater decrease in internal foot progression than with TheraTogs (Table 1).
In addition to the kinematic data, gait temporal-spatial characteristics were examined in each bracing condition. These included velocity (meters per minute), cadence (steps per minute), stride length (meters), and double-limb stance (initial + terminal stance phase of gait). Gait characteristics were expressed in absolute values as well as a percentage of RS values for the subject's age (Figure 3). At baseline with AFOs only, the subject's gait velocity was 72% of the RS, less than typical for her age because of a decreased cadence. In both of the other conditions, the subject's gait velocity decreased versus the baseline condition, although substantially more with AFOs and TCs than with AFOs and TheraTogs (67% and 56% of the RSs, respectively). With TheraTogs, the decline was largely due to decreased stride length (82% of the RS), whereas with TCs it was due to decreased cadence (59% of the RS) (Figure 3). Although the subject spent a larger percentage of time than typically expected in double-limb stance (176% of the RS) at baseline (indicating instability), she presented with a greater increase in double-limb stance with both AFOs and TheraTogs (196% of the RS) and AFOs and TCs (207% of the RS) (Figure 3). Of note, the weight of TCs with AFOs was 0.7 kg, 5% of the subject's body weight, and the weight of TheraTogs with AFOs was 0.3 kg, 2% of the subject's body weight.
Parent satisfaction with TCs and TheraTogs was measured with a survey using a 5-point Likert scale, with 1 = strongly agree and 5 = strongly disagree (Table 2). Scores indicated that her mother preferred TheraTogs greatly over TCs. She indicated that she was very pleased with the ease of donning the TheraTogs, and with how the subject tolerated wear. Her survey after the use of TCs indicated that the subject did not tolerate wearing them well and did not walk well when wearing them. She was able to wear the TheraTogs an average of 8.5 hours a day, whereas she wore the TCs an average of 15 minutes per day.
In this case, external rotation of both lower extremities was achieved with both TheraTogs and TCs, helping correct in-toeing gait measured dynamically through foot progression. The difference between the interventions was the source of the external rotation. TheraTogs corrected in-toeing by excessively externally rotating the hips. The values for hip rotation with the use of TCs were closer to RS (less excessively external) than with the use of TheraTogs, indicating that improved foot progression with TCs was achieved by rotating the lower leg with respect to the thigh via the knee joint. Since TheraTogs caused external rotation at the hip instead of the knee, their use may actually decrease the stress through the knees and prevent future knee problems such as ligamentous instability, arthritis, and pain, which are common in the older SB patient population.3 A slight overcorrection of foot progression on the right and an undercorrection on the left was seen with the TheraTogs, which may be related to the strapping technique. The strapping technique used in our intervention involved wrapping a strap around the posterior aspect of the lower thigh, which had the effect of flexing the knee in stance phase. Excessive knee flexion during gait in children with myelomeningocele is associated with knee pain later in life3 and should be prevented if possible. After the intervention was completed, the mother was instructed in an alternative strapping technique, which improved knee position in stance by passing the strap in front of, rather than behind, the distal thigh and knee. Although flexibility of application is a significant advantage to TheraTogs, education is needed for the parent in the correct strapping technique. Variability of application is not an issue with TCs as they are set in the optimal alignment determined by the orthopedist and the orthotist. There is less potential for errors in application of TCs since they are attached directly to AFOs. The only potential for variation is in the tension with which the pelvic strap is fastened, which, if too loose, may allow pelvic rotation.
The increased knee flexion in stance phase seen during ambulation in TheraTogs decreased the subject's stride length. In spite of this, her gait velocity was closer to the baseline condition than with TCs due to higher cadence. Stride length was greater with the use of the TCs than with the use of TheraTogs, but cadence may have been limited by their weight. Overall, the TCs allowed temporal-spatial values that more closely approximated RSs for gait.
The parent of our subject indicated her strong preference for TheraTogs in the satisfaction survey. In additional comments, she stated that she preferred the appearance of TheraTogs and felt that they were easy to don and use. The subject did not tolerate TCs well, which significantly decreased her compliance with wear. TheraTogs are lightweight in comparison with TCs, which may partially explain the patient's ability to wear them for longer periods than TCs. The parent also felt that the subject walked better overall with TheraTogs, even though the gait analyses indicated better kinematic data with TCs.
Limitations of this case report include involving a single subject, so that the results cannot be generalized to the intended population. The patient had no prior experience with either device, and because of logistical constraints, she used TheraTogs first. It is possible that both the child's and the parent's acceptance of TCs may have been different if they had been used first. Because of the configuration of TCs, kinematic knee markers had to be placed on the outside of the brace, which may have affected the kinematic data obtained. The intervention time for both TheraTogs and TCs was relatively short, but evidence to support ideal wear time is not available in the literature at this time. Future studies should include patients with varied levels of SB and standardized wear time for TheraTogs. Finally, identification of characteristics, such as neurosegmental level, of patients who benefit most from the use of TheraTogs would be useful.
In this case report, correction of in-toeing due to excessive internal tibial torsion was achieved with both TheraTogs and TCs. Use of TheraTogs decreased in-toeing by excessively externally rotating the hips, whereas TCs affected foot progression through external rotation at the knee. In this case, TCs corrected in-toeing more effectively, but the subject and her parent showed a strong preference for TheraTogs. Although TCs were more effective, it is possible that equivalent correction of in-toeing could be achieved in smaller, younger children with the use of TheraTogs. This is accomplished through strapping techniques that are individually tailored to the child's specific alignment.
Clinicians need to consider if the site of derotation (hip vs knee) is imperative in decreasing in-toeing in SB, or if improved alignment of the foot with increased compliance is the goal. TheraTogs were effective in management of in-toeing for this subject with her specific level of innervation, height, and weight. Therefore, TheraTogs may be a viable option for correcting in-toeing in children with SB. Further research is needed to determine the anthropometric measures and level of function for which TheraTogs application would be the most successful.
We thank Lerman and Son Orthotics and Prosthetics for its contribution of the AFOs and TCs for the intervention.
© 2012 Lippincott Williams & Wilkins, Inc.