Development and preliminary evaluation of a new anatomically based prosthetic alignment method for below-knee prosthesis

ABSTRACT

The objectives of current study were to a) assess similarities and relationships between anatomical landmark-based angles and distances of lower limbs in unilateral transtibial amputees and b) develop and evaluate a new anatomically based static prosthetic alignment method. First substudy assessed the anthropometrical differences and relationships between the lower limbs in the photographs taken from amputees. Data were analyzed via paired t-test and regression analysis. Results show no significant differences in frontal and transverse planes. In the sagittal plane, the anthropometric parameters of the amputated limb were significantly correlated to the corresponding variables of the sound limb. The results served as bases for the development of a new prosthetic alignment method. The method was evaluated on a single-subject study. Prosthetic alignment carried out by an experienced prosthetist was compared with such alignment adjusted by an inexperienced prosthetist but with the use of the developed method. In sagittal and frontal planes, the socket angle was tuned with respect to the shin angle, and the position of the prosthetic foot was tuned in relation to the pelvic landmarks. Further study is needed to assess the proposed method on a larger sample of amputees and prosthetists.

KEYWORDS:

• anatomical landmarks
• anthropometry
• laser instrument
• prosthetic alignment
• transtibial prosthesis

Acknowledgments

The authors would like to thank the staff and prosthetists of Kowthar Orthotics and Prosthetics Center and Mr. Ali Khalaf for their help in the sample recruitment and data collection.