Patent ID: 8246694

Claim:
A locking liner comprising: an elastomeric liner having a closed distal end and an open proximal end for donning over a residual limb of a below-the-knee amputee, said liner sized and configured to surround a residual limb of a patient and 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 having 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; an insert member molded into the distal end of said liner and adapted to receive a connector for locking said liner into a prosthetic socket when worn on a residual limb of a patient; 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 liner 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 liner behind the knee is substantially reduced or eliminated.