Related Experiment Video
Updated: Aug 3, 2026
10:45
A Simple Microfluidic Chip for Long-Term Growth and Imaging of Caenorhabditis elegans
Published on: April 11, 2022
Vulpius and Z-lengthening
1Shriners Hospital for Crippled Children, Houston, Texas, USA.
Journal of Pediatric Orthopedics
|November 1, 1996
Summary
Both Vulpius and Z-lengthening procedures improved ankle function in cerebral palsy patients. Gait analysis showed similar, satisfactory outcomes for both gastrocnemius fascia and Achilles tendon lengthening surgeries one year post-operation.
Area of Science:
- Orthopedic Surgery
- Pediatric Orthopedics
- Biomechanical Analysis
Background:
- Cerebral palsy (CP) often involves gait abnormalities, particularly equinus deformity.
- Gastrocnemius fascia lengthening (Vulpius procedure) and Achilles tendon lengthening (Z-lengthening) are common surgical interventions.
- Evaluating the functional outcomes of these procedures on ankle biomechanics is crucial for patient management.
Purpose of the Study:
- To compare the effectiveness of Vulpius lengthening versus Z-lengthening of the Achilles tendon in improving ankle function in ambulatory cerebral palsy patients.
- To analyze changes in ankle motion, moment, and power before and after surgical intervention.
Main Methods:
- Gait analysis was performed on 33 ambulatory cerebral palsy patients before and approximately one year after surgery.
- Patients underwent either Vulpius lengthening of the gastrocnemius fascia (n=22) or Z-lengthening of the Achilles tendon (n=27).
- Simultaneous hip or knee surgeries were common; gait parameters included ankle motion, moment, and power.
Main Results:
- Both surgical groups demonstrated improved ankle moments, approaching normal values post-operatively.
- No significant differences in gait parameters were observed between the Vulpius and Z-lengthening groups at follow-up.
- Significant improvements were noted within each group from pre- to post-operative measurements, including reduced abnormal midstance work (Vulpius) and decreased equinus with increased push-off work (Z-lengthening).
Conclusions:
- Both Vulpius lengthening and Z-lengthening of the Achilles tendon provide satisfactory and comparable outcomes for improving ankle function in ambulatory cerebral palsy patients.
- These procedures lead to significant biomechanical improvements in ankle function one year after surgery.
- The choice between Vulpius and Z-lengthening may not significantly impact functional ankle outcomes in this patient population.
Related Concept Videos
01:10Interference: Path Lengths
Consider two sources of sound, that may or may not be in phase, emitting waves at a single frequency, and consider the frequencies to be the same.
Two special sources may be considered when they are in phase. This can be easily achieved by feeding the two sources from the same source. An example would be synchronizing the two speakers by feeding them with the same source, such as the sound waves produced by a tuning fork. This setup ensures that the two sources have the same frequency and are...
Two special sources may be considered when they are in phase. This can be easily achieved by feeding the two sources from the same source. An example would be synchronizing the two speakers by feeding them with the same source, such as the sound waves produced by a tuning fork. This setup ensures that the two sources have the same frequency and are...
01:16Zener Diodes
Zener diodes are specialized semiconductor devices designed to operate in the reverse breakdown region, where they allow current to flow into the cathode, making it positive relative to the anode. This reverse operation distinguishes Zener diodes from conventional diodes and enables their use in various applications, most notably as voltage regulators. One of the defining characteristics of Zener diodes is their nearly vertical I-V (current-voltage) characteristic curve above a certain...
01:26Definition of z-Transform
The z-transform is a powerful mathematical tool used in the analysis of discrete-time signals and systems. It is an essential analytical tool, analogous to the Laplace transform used in continuous-time systems. It plays a crucial role in the analysis of signals and systems, complementing the discrete-time Fourier transform. Both the z-transform and the Laplace transform convert differential or difference equations into algebraic equations, simplifying the process of solving complex problems.
01:16Properties of the z-Transform II
The property of Accumulation in signal processing is derived by analyzing the accumulated sum of a discrete-time signal and using the time-shifting property to determine its z-transform. This principle reveals that the z-transform of the summed signal is related to the z-transform of the original signal by a multiplicative factor.
Moreover, the convolution property indicates that the convolution of two signals in the time domain corresponds to the product of their z-transforms in the frequency...
Moreover, the convolution property indicates that the convolution of two signals in the time domain corresponds to the product of their z-transforms in the frequency...
01:29Complex Zeros
Complex zeros are the solutions to polynomial equations that include imaginary numbers, specifically, numbers of the form a + bi, where a and b are real numbers and i is the imaginary unit defined by i2=-1. These zeros satisfy the equation P(x) = 0, where P(x) is a polynomial with real or complex coefficients. Since the complex number system includes all real numbers, it provides a complete framework for analyzing all possible roots of a polynomial.Every polynomial of degree n≥1 can be...
01:20Torsion in Vector Calculus
A toy train ascending a winding track that curves and tilts offers an intuitive view of torsion, a key geometric concept in the study of space curves. While curvature measures how sharply a path bends, torsion captures how the path twists out of the plane of bending. This twisting behavior is crucial in understanding three-dimensional motion and is precisely described using the Frenet–Serret framework.At each point along a space curve, the Frenet–Serret frame consists of three orthogonal unit...