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Genu recurvatum in spastic cerebral palsy. Report on findings by gait analysis
Insights
Genu recurvatum in children with spastic cerebral palsy is caused by tibial motion arrest. Fixed-ankle braces improved knee joint moments, but their mechanism for permanent correction remains unclear.
Area of Science:
- Biomechanics
- Orthopedics
- Pediatric Rehabilitation
Background:
- Genu recurvatum, characterized by knee hyperextension, is a common gait deviation in spastic cerebral palsy.
- Understanding the underlying mechanisms is crucial for effective intervention.
Purpose of the Study:
- To analyze the gait patterns of children with spastic cerebral palsy and genu recurvatum.
- To determine the mechanisms producing genu recurvatum.
- To evaluate the effect of fixed-ankle below-the-knee orthoses on genu recurvatum.
Main Methods:
- High-speed motion analysis, electromyography, and force plate measurements were used.
- Gait patterns of 15 children (4-16 years) with spastic cerebral palsy and genu recurvatum were analyzed.
- Data were computer-analyzed to identify kinematic and kinetic factors.
Main Results:
- Genu recurvatum occurred when forward tibial progression ceased during stance phase.
- Calf muscle activity or insufficient strength contributed to tibial arrest in different patient groups.
- Fixed-ankle orthoses normalized joint moments, particularly at the knee.
Conclusions:
- Genu recurvatum in this population is primarily linked to tibial motion dynamics during gait.
- Fixed-ankle orthoses show potential for improving knee joint mechanics.
- The mechanism for permanent correction of genu recurvatum by orthoses requires further investigation.
Abstract:
Using high-speed motion pictures, electromyography, a dynamic piezoelectric force plate, and computer analysis of the data, the gait patterns of fifteen children, four to sixteen years old, with spastic cerebral palsy and genu recurvatum were analyzed to determine the mechanisms producing genu recurvatum and the effect of fixed-ankle below-the-knee orthoses. In all children the recurvatum during stance phase began when the tibia stopped moving forward and disappeared when tibial movement resumed. In six patients (Group I), excessive activity of the calf muscles in response to the increasing dorsiflexion moment about the ankle produced by the foot-floor reaction force arrested the forward motion of the tibia. In six others (Group II), the contraction of the calf muscles was not sufficiently strong to resist the dorsiflexion moment and the tibia moved forward until maximum dorsiflexion had occurred and then stopped. In both instances recurvatum was produced when the femur continued to move forward over the stationary tibia and an extension moment was produced at the knee. In no patient did activity of the knee flexors prevent recurvatum, which was eliminated only by resumption of forward movement of the tibia. This movement of the tibia was produced either by heel-off (Group I) or by sudden unweighting of the limb due to opposite heel-strike (Group II). In Group I, when tibial motion stopped in the first half of stance phase the position of the hip rapidly changed from flexion to extension and there was forward leaning of the trunk, while in Group II the change from hip flexion to extension occurred with backward leaning of the trunk. The fixed-ankle below-the-knee orthosis, by preventing excessive dorsiflexion and plantar flexion, produced more normal moments about all joints, especially the knee. In the three children (Group III) whose recurvatum was permanently corrected by the brace, no explanation for the improvement was evident in these studies.