Abstract: The invention provides a tendon or ligament prosthesis having an undeployed configuration and a deployed configuration. The prosthesis has a resistance to tension in the undeployed configuration that is less than its resistance to tension in the deployed configuration. In the deployed configuration, the prosthesis is capable of twisting and bending. In one embodiment, the prosthesis has a meshwork of filaments woven, knitted or braided into a slender cylinder. In this embodiment, the prosthesis attains the deployed configuration by stretching the prosthesis from its undeployed configuration. The prosthesis may be used, for example, to replace an anterior or posterior cruciate ligament or to treat acromioclavicular joint separation, a rotator cuff tear, lateral collateral ligament tears, medial collateral ligament tears, or medial patello-femoral ligament tears. The invention also provides a method for replacing a tendon or ligament using the prosthesis of the invention.