Margin convergence: a method of reducing strain in massive rotator cuff tears.

Increases security of fixation in rotator cuff repair is usually achieved by increasing the strength of fixation. Paradoxically, the problem can be approached by techniques that decrease the strain at the margins of the tear so that weaker fixation will still be adequate. Such techniques provide greater safety tolerances for the strength characteristics of suture, tendon, and bone. The principle of margin convergence can be applied to rotator cuff repair as a means to enhance the security of fixation by decreasing the mechanical strain at the margins of the tear. This strain reduction should also contribute to pain reduction by virtue of decreased stimulation of mechanoreceptors in the rotator cuff. The cliché no pain, no strain can be converted to a paradigm by reversal of its components to no strain, no pain.