Rotator cuff therapy using muscle fiber fragments

Abstract

Methods and compositions are disclosed for repair of shoulder injuries by employing disaggregated muscle fiber fragments to regenerate functional shoulder muscle tissue. In some embodiments, the fragments retain functional satellite cells but exhibit cell wall rupture and have an average size of less than 150 μm. The methods include the preparation and implantation of compositions by extracting muscle tissue from a donor site, disaggregating muscle fibers from the extracted tissue, and fragmenting disaggregated muscle fibers into fiber fragments that exhibit cell wall rupture and preferably have an average size of less than 150 microns, more preferable less than about 100 microns, while retaining functional satellite cells. Upon injection, e.g., into the supraspinatus or other rotator cuff muscles, the muscle fiber fragment compositions are capable of reconstituting or reconstructing elongated muscle fibers from the fragments and orienting in alignment with native shoulder muscle fibers.