Prosthetic liner with improved knee flexion
A prosthesis comprising an elastomeric liner sized and configured to surround a limb of a patient about a knee joint, the liner having an inner surface for facing the limb of the patient and an outer surface defining an anterior region and a posterior region which are demarcated by an imaginary plane extending midway between the front most portion and rear most portion of the limb along the length of the limb, wherein the anterior region has an anterior material secured thereto and the posterior region has a posterior material secured thereto and the anterior and posterior materials having equal transverse elongation, and the anterior material having a longitudinal elongation greater than the longitudinal elongation of said posterior material, whereby when said prosthesis is donned onto a limb of a patient over the knee and the limb is flexed about the knee, buckling of the prosthesis about the knee is substantially reduced or eliminated.
1. A prosthesis comprising:
an elastomeric liner sized and configured to surround a limb of a patient about a knee joint, said liner adapted to extend above and below said knee joint;
said liner having an elastomeric inner layer defining an inner surface for facing the limb of the patient and an outer surface; said outer surface defining an anterior region and a posterior region; said regions being demarcated by an imaginary plane extending substantially midway between the front most portion and rear most portion of the limb along the length of the limb when said liner is worn;
said anterior region of said outer surface having an elastomeric anterior single unitary piece of material secured thereto; said posterior region of said outer surface having an elastomeric posterior single unitary piece of material secured thereto;
said anterior piece of material being coextensive with said posterior piece of material;
said anterior and posterior materials having edge portions extending along said imaginary plane and secured together, wherein said edge portions are secured together along substantially their entire lengths;
said anterior and posterior materials each having a predetermined transverse elongation;
said anterior material having a longitudinal elongation in the range of from about 30% to about 180%;
said posterior material having a longitudinal elongation in the range of from about 5% to about 75%;
said elastomeric inner layer having greater transverse and longitudinal elongations than said anterior and posterior materials; and
said anterior and posterior materials each having a longitudinal elongation selected from said range of longitudinal elongations and each having said predetermined transverse elongation such that when said prosthesis is donned onto a limb of a patient over the knee and the limb is flexed about the knee, the anterior material over the knee stretches longitudinally and contracts transversely causing the posterior material behind the knee to stretch transversely which, in turn, causes the posterior material to contract longitudinally thereby buckling of the prosthesis behind the knee is substantially reduced or eliminated.
2. A prosthesis as claimed in claim 1 , wherein said anterior material having a longitudinal elongation in the range of from about 50% to about 150%.
3. A prosthesis as claimed in claim 2 , wherein said posterior material having a longitudinal elongation in the range of from about 5% to about 50%.
4. A prosthesis as claimed in claim 1 , wherein said posterior material having a longitudinal elongation in the range of from about 5% to about 50%.
5. A prosthesis as claimed in claim 4 , wherein said anterior material having a longitudinal elongation in the range of from about 50% to about 150%.
6. A prosthesis as claimed in claim 1 , wherein said anterior and posterior materials both have a transverse elongation in the range of from about 50% to about 250%.
7. A prosthesis as claimed in claim 6 , wherein said anterior material having a longitudinal elongation in the range of from about 50% to about 150%.
8. A prosthesis as claimed in claim 7 , wherein said posterior material having a longitudinal elongation in the range of from about 5% to about 50%.
9. A prosthesis as claimed in claim 6 , wherein said posterior material having a longitudinal elongation in the range of from about 5% to about 50%.
10. A prosthesis as claimed in claim 9 , wherein said anterior material having a longitudinal elongation in the range of from about 50% to about 150%.
11. A prosthesis as claimed in claim 1 , wherein said anterior and posterior materials both have a transverse elongation in the range of from about 75% to about 225%.
12. A prosthesis as claimed in claim 11 , wherein said anterior material having a longitudinal elongation in the range of from about 50% to about 150%.
13. A prosthesis as claimed in claim 12 , wherein said posterior material having a longitudinal elongation in the range of from about 5% to about 50%.
14. A prosthesis as claimed in claim 11 , wherein said posterior material having a longitudinal elongation in the range of from about 5% to about 50%.
15. A prosthesis as claimed in claim 14 , wherein said anterior material having a longitudinal elongation in the range of from about 50% to about 150%.
16. A prosthesis as claimed in any one of claims 1 - 15 , wherein the liner comprises a distal closed end and an open proximal end for donning over a residual limb of a below-the-knee amputee.
17. A prosthesis as claimed in any one of claims 1 - 15 , wherein said edge portions are secured together by adhering overlapping edges, cross-stitching abutting edges, or sewing a strip of material across abutting edges.