A composition comprising a human- or animal-derived extracellular matrix and a macromolecular network which is prepared ex vivo is provided that is useful in the repair of a tissue injury, particularly in repair of tears or gaps between a tendon and a bone, such as in a rotator cuff tear. In an embodiment, the composition comprises a human- or animal-derived extracellular matrix having impregnated therein a macromolecular network of hyaluronan macromolecules that have been cross-linked via dihydroxyphenyl linkages, so that the cross-linked network is interlocked within the extracellular matrix. The resulting HA-incorporated extracellular matrix can be supplied in the form of a patch to reinforce a tissue repair or cover a tissue defect.