Independent ambulators with high sacral myelomeningocele: the relation between walking kinematics and energy consumption.

The aims of this study were to determine the relation between gait kinematics (center of mass excursions) and measures of oxygen consumption and oxygen cost. Fourteen independent ambulating children with myelomeningocele (nine females, five males; mean age 8 years 7 months) and thirteen children with no history of neuromuscular disorder were evaluated. At their comfortable walking speed all patients exhibited oxygen cost and oxygen consumption values that exceeded the normal level by more than 1 SD. Pelvic obliquity demonstrated the strongest relation with oxygen cost which suggests that ultimately hip abductor strength may play a key role in energy demands during gait. Despite the exaggerated pelvic kinematics, vertical and horizontal center of mass excursions of the trunk and whole-body during the gait cycle were not significantly greater than normal (p>0.05). Decreased self-selected walking velocity at which many of these children consider comfortable and stable may be predicated on an optimal center of mass movement that approximates the magnitude observed in normal gait. The slower walking velocity decreases walking efficiency. Conversely, the increased center of mass movement that would accompany a faster gait would probably impose intolerable oxygen consumption levels. Strengthening programs that focus on the gluteus medius and maximus to decrease compensatory trunk and pelvic motions, allowing the patients to adopt a faster gait without exacerbating kinematic and center of mass motions and which enabled more efficient walking hold promise for these patients.

Internal derotation osteotomy of the tibia: pre- and postoperative gait analysis in persons with high sacral myelomeningocele.

Rotational deformities of the lower extremities are common in patients with myelomeningocele. In these situations, surgical correction is often necessary. We conducted a retrospective review of eight ambulatory patients with high sacral myelomeningocele and external tibial torsion who underwent 10 distal tibia and fibular internal derotation osteotomies. All patients had an increased valgus knee stress preoperatively. Pre- and postoperative three-dimensional gait analysis was used to evaluate coronal plane knee moments and dynamic sagittal plane knee motion. Postoperatively, a significant improvement in the abnormal internal knee varus moment (p < 0.005) as well as a significant increase in the stance phase knee extension (p < 0.01) was seen. Three patients had resolution of preoperative knee pain. We believe that patients with increased knee stress secondary to excessive external tibial torsion will benefit from a tibial derotation osteotomy that could delay or prevent the onset of late degenerative changes about the knee.

External tibial torsion and the effectiveness of the solid ankle-foot orthoses.

The aims of this study were to determine the influence of external tibial torsion on the effectiveness of the ankle-foot orthoses (AFO) in children with lumbosacral myelomeningocele. Forty patients with normal tibial rotation and 18 patients with excessive external tibial torsion were evaluated with three-dimensional gait analysis at their comfortable walking speed. The group with normal tibial rotation showed significantly greater knee extension and lower mean extension moment compared with the group with external tibial torsion (p < 0.05). The posteriorly and laterally deviated ground-reaction force relative to the knee-flexion axis compromises the ability of this force to facilitate knee extension. Patients with torsional magnitudes >20 degrees demand close inspection as candidates for derotation osteotomy. The AFO will continue to stabilize the ankle-foot complex, but improved knee motion, knee-extensor activity, and ultimately walking efficiency may be compromised.

Valgus knee stress in lumbosacral myelomeningocele: a gait-analysis evaluation.

Twenty-five independent community-ambulating patients with lumbosacral-level myelomeningocele (N = 50 limbs) underwent gait analysis. The limbs of these patients were divided into two groups based on thigh-foot angle (TFA): Group I (n = 20) had marked external tibial torsion, TFA > or = 20 degrees, and group II had TFA between 10 and 20 degrees. Ten limbs were excluded because of neutral or internal alignment. Twenty normal limbs with TFA = 10 degrees served as controls. An abnormal internal varus knee stress during stance was identified in all group I limbs and 12 (70%) of 20 limbs group II limbs compared with controls, which demonstrated an internal valgus stress. This internal varus moment was greater in group I limbs than in the abnormal limbs in group II (p < 0.05). Knee flexion was the only other parameter found to correlate with this stress and only in group I limbs. We conclude that (a) in this patient group, increased external tibial torsion is likely to result in an abnormal internal varus knee stress; (b) TFA > 20 degrees appears significantly to increase this stress; and (c) knee flexion is an important related parameter, but only in limbs with TFA between 10 and 20 degrees. We believe that this abnormal stress may predispose the knee to late arthrosis and that derotational osteotomies to normalize the TFA may prove to have a favorable long-term effect.

The influence of forearm crutches on pelvic and hip kinematics in children with myelomeningocele: don't throw away the crutches.

Gait analysis was performed on 16 children with high-sacral-level myelomeningocele who walked with and without crutches to evaluate the influence of crutches on their unique walking pattern. All of the patients used solid ankle-foot orthoses (AFOs). Deviations in coronal and transverse planes improved with assisted walking. The timing of stance phase pelvic depression and the magnitude of stance phase hip abduction improved with crutch walking. Pelvic rotation, which was seven times the normal range of motion during no-crutch walking, decreased to four times normal with crutches. Walking velocity was not significantly different between conditions. The results demonstrated that deviations in pelvic and hip kinematics are related to muscle weakness and improve with crutch use. Crutches enable the patient to transfer some weight bearing to their upper extremities which decreases the demand on weak lower-extremity musculature. This allows them to maintain functional ambulation with a closer to normal gait pattern.

Gait electromyography in children with myelomeningocele at the sacral level.

OBJECTIVE: Patients with sacral level myelomeningocele can be expected to maintain a high level of ambulatory status long into adulthood. Gait deterioration and knee pain reported in this population may be attributed to compensatory movements and increased recruitment of less affected muscle groups to achieve this desired level of ambulation. The objective of this study was to analyze the effect of the solid ankle-foot-orthoses (AFOs) on the muscular activity of selected muscles during walking. DESIGN: Cohort/outcome. SETTING: Laboratory. PATIENTS: Twenty four patients with sacral level myelomeningocele between 4 to 17 years of age. INTERVENTION: Electromyographic activity of selected muscle groups were studied during barefoot walking and walking with solid AFOs at a self-selected walking velocity. MAIN OUTCOME MEASURES: Timing of electromyographic activity and sagittal plane knee kinematics. Comparison to normal electromyographic patterns and changes between barefoot and AFO walking conditions. RESULTS: With the AFOs there was significantly less prolonged stance phase quadriceps activity compared with barefoot walking, although greater than normal activity persisted. There was no change between conditions for the other monitored muscle groups. All muscles elicited greater duration of activity over the course of the gait cycle. CONCLUSIONS: Our results show that solid AFOs improve the prolonged knee extensor activity evident for barefoot walking. This is clinically relevant to the gait deterioration and knee pain sometimes seen in this patient population. We espouse early and persistent orthotic intervention to reduce compensatory muscular overactivity and maintain gait quality.