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Alignment of trans-tibial prostheses based on roll-over shape principles
1Department of Physical Medicine and Rehabilitation, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.
Prosthetics and Orthotics International
|October 24, 2003
Summary
Prosthetic feet alignment can be optimized by matching their roll-over shape to an ideal, able-bodied model. This computational approach ensures effective prosthetic alignment, improving outcomes for users.
Area of Science:
- Biomechanics
- Prosthetics and Orthotics
- Biomedical Engineering
Background:
- The roll-over shape alignment hypothesis suggests prosthetic feet should mimic the ideal shape of an able-bodied foot-ankle system.
- Current prosthetic alignment methods may not consistently achieve optimal foot roll-over shapes.
Purpose of the Study:
- To investigate the roll-over shape alignment hypothesis for prosthetic feet.
- To develop and evaluate a computational alignment system for trans-tibial prostheses based on this hypothesis.
Main Methods:
- Developed a computational alignment system to set trans-tibial alignments based on the roll-over shape hypothesis.
- Compared roll-over shapes of three prosthetic feet aligned by the system, standard clinical techniques, and a prosthetist team.
- Assessed alignment using both computational system and manual prosthetist alignment, with a control group receiving no specific alignment.
Main Results:
- No significant difference was found between the computational system's alignment and standard clinical techniques (p = 0.944).
- Significant differences were observed between unaligned prostheses and those aligned by prosthetists (p = 0.006) or the computational system (p = 0.024).
- Results support the hypothesis that matching prosthetic foot roll-over shape to an ideal is the primary goal of alignment.
Conclusions:
- The roll-over shape alignment hypothesis is supported by the study's findings.
- A computational system can achieve alignment comparable to clinical standards, validating the hypothesis.
- Using an ideal roll-over shape as an alignment goal may enable pre-fabrication (a priori) alignment, potentially reducing hardware needs and benefiting low-income settings and lightweight prosthesis development.
