RecruitingClinical trialMuscle Fiber Fragments for Improved Function of Rotator Cuff Musculature Following Rotator Cuff RepairIn this study, a chest muscle sample (biopsy) will be taken and the muscle fibers will be removed from the sample and made into smaller strands or fragments. During this same procedure, those muscle fiber fragments (MFFs) will then be injected directly into the supraspinatus muscle. Once injected, the MFFs will remain in the supraspinatus where Investigators believe the MFF will become part of the participants' existing muscle and provide increased muscle size and strength, improving function (rotator cuff strength and stability).