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The effect of rectus EMG patterns on the outcome of rectus femoris transfers
F Miller1, R Cardoso Dias, G E Lipton
1The Alfred I. duPont Institute, Wilmington, Delaware 19899, USA.
Insights
Preoperative electromyography (EMG) of the rectus femoris muscle in children with cerebral palsy predicts outcomes of stiff-knee gait surgery. Identifying specific muscle activity patterns can guide treatment for improved knee flexion post-operation.
Area of Science:
- Orthopedics
- Pediatric Rehabilitation
- Movement Science
Background:
- Cerebral palsy (CP) often causes stiff-knee gait, impacting mobility in children.
- Rectus femoris transfer to the sartorius is a surgical intervention to address this condition.
- Predicting surgical outcomes is crucial for optimizing treatment strategies.
Purpose of the Study:
- To investigate the predictive value of preoperative electromyographic (EMG) activity of the rectus femoris muscle on surgical outcomes.
- To correlate specific rectus femoris EMG patterns with improvements in knee flexion after surgery.
Main Methods:
- Retrospective review of 25 children with CP and stiff-knee gait who underwent rectus femoris transfer.
- Preoperative and postoperative gait analysis, including EMG, was performed.
- Patients were categorized into three groups based on preoperative rectus femoris EMG patterns during the gait cycle.
Main Results:
- Significant improvements in peak knee flexion were observed across all groups post-surgery.
- Group I (predominant swing-phase rectus femoris activity) showed the greatest improvement in knee flexion (26 degrees).
- Group II (constant rectus femoris activity) and Group III (normal rectus femoris activity) showed lesser improvements (18 and 12 degrees, respectively).
Conclusions:
- Preoperative EMG patterns of the rectus femoris muscle are predictive of functional outcomes after transfer surgery in children with CP.
- Identifying specific EMG patterns, particularly predominant swing-phase activity, can help anticipate greater improvements in knee flexion.
- EMG analysis can aid in patient selection and surgical planning for rectus femoris transfer to optimize gait in children with CP.
Abstract:
Rectus femoris transfer to the sartorius is performed in children with cerebral palsy to treat stiff-knee gait. To determine whether preoperative electromyographic (EMG) activity of the rectus femoris is predictive of outcome, we studied 25 children with stiff-knee gait who had preoperative EMG gait analysis before rectus femoris transfer. Fifteen patients had bilateral surgery, and 10 patients had unilateral surgery. The mean age at surgery was 9.6 years for the retrospective review. Patients were divided into three groups based on the recorded EMG patterns of the rectus femoris during the gait cycle. Group I patients had predominant swing-phase activity only. Group II patients had constant rectus activity through the entire gait cycle. Group III patients had normal rectus, defined as minimal EMG activity in the last 75% of swing phase. A repeated gait analysis at a mean of 1.5 years after surgery was available for comparison. In group I, mean peak knee flexion increased 26 degrees after surgery from 44 to 70 degrees. In group II, mean peak knee flexion increased 18 degrees after surgery from 51 to 69 degrees. In group III, mean peak knee flexion increased 12 degrees from 54 to 66 degrees. Results of this study show the greatest improvement in outcome, as measured by knee flexion, occurred in group I in which the rectus fired predominantly in swing phase. Preoperative EMG patterns are therefore useful in determining the outcome after rectus femoris transfer to the sartorius.