Quantitative methods and criteria for modifying and defining transtibial prosthetic alignment: A systematic review

Area of Science:

• Prosthetics and Orthotics
• Biomechanics
• Rehabilitation Engineering

Background:

• Evaluating and correcting prosthetic alignment is crucial for optimal function in individuals with transtibial amputations.
• Current clinical alignment methods are largely subjective and lack standardized objective criteria.
• Defining a universally accepted, objective (a priori) alignment criterion remains a challenge.

Purpose of the Study:

• To systematically review objective techniques for evaluating and correcting prosthetic alignment.
• To examine proposed methods for establishing a predefined (a priori) alignment criterion based on clinical acceptance.
• To assess the current evidence regarding the efficacy and limitations of objective alignment assessment tools.

Main Methods:

• A comprehensive literature search was conducted across 5 online databases, supplemented by hand searching reference lists.
• Quality assessment of included studies was performed using the American Academy of Orthotics and Prosthetics checklists.
• Data synthesis focused on methodologies, approaches, instrumentation, and alignment steps across 20 studies involving 247 adult transtibial amputees.

Main Results:

• No single objective technique fully replaces the current clinical approach to prosthetic alignment.
• Certain instruments, like those measuring socket base moments or visualizing ground reaction forces, can assist in quantifying and adjusting alignment.
• A universal a priori alignment criterion is not feasible due to individual variability and the complexity of alignment.

Conclusions:

• While a universal objective alignment standard is not currently achievable, objective tools can support clinical decision-making.
• Individualized alignment configurations are critical for prosthetic user acceptance and function.
• Combining anatomical-based alignment with biomechanical measurement tools may offer a path toward objectively quantifying patient-specific a priori alignment.