The goal of this study is to assess whether undergoing surgical repair of the rotator cuff with the additional intervention of whole blood fibrin clot will improve rotator cuff vascularization at the bone-tendon interface repair site and patient outcomes compared to those who do not receive the whole blood fibrin clot intervention.

Patient outcomes after rotator cuff repair vary greatly and depend on the size of the tear itself. Researchers have identified a number of devices that can be used to reinforce the surgical repair and enhance the structure and function of both the muscles and tendons (Jo et al., 2011; Randelli, Arrigoni, Ragone, MEng, Aliprandi, Cabitza, 2011; Proctor, 2014). Reinforcement patches have been used to help improve surgical outcomes, including: allograft rotator cuff, human cadaveric skin, pig and bovine skin, equine pericardium, and porcine intestinal submucosa (Randelli, Arrigoni, Ragone, MEng, Aliprandi, Cabitza, 2011). Although synthetic patches have also shown some effectiveness, these patches do not provide biologic augmentation of the tendon repair (Jo et al., 2011).

Additionally, there has been some research examining the effectiveness of using platelet-rich plasma therapy to help repair both rotator cuff tendinopathy and tears. Platelets play an important role in the healing process and it has been theorized that exposing inflamed or healing tissue to higher densities of platelets can contribute to less pain, better range of motion (ROM), and overall healing (Pandey et al., 2016). The consensus on this type of therapy has shown inconclusive results, however. For example, research by Jo et al. (2011) found no significant change in clinical recovery in respect to pain or ROM compared to a control group. Alternatively, Pandey et al. (2016) found significant improvements in both pain and ROM scores as well as decreased re-tear rates in the plasma-rich protein treatment group. These and other similar studies utilized different methodologies for patient populations (tendinopathy versus full tears, etc.), treatment timing, formulation of platelet-rich plasma or whole blood fibrin clot, and time of follow-up. Further research is needed to identify what treatments, if any, in the field of platelet-rich plasma are most beneficial for patients with rotator cuff tears. Recent research has demonstrated that whole blood fibrin clots concentrate 98% of available platelets and release growth factors including vascular endothelial growth factor over two weeks (Siegel, Clevenger, Proctor, Clegg, & Proctor, 2017). However, clinical evidence indicating the effect of whole blood fibrin clots on the healing of repaired torn rotator cuffs is lacking (Jo et al., 2011). The goal of this study is to assess whether undergoing surgical repair of the rotator cuff with the additional intervention of whole blood fibrin clot will improve rotator cuff vascularization at the bone-tendon interface repair site and patient outcomes compared to those who do not receive the whole blood fibrin clot intervention.

Inclusion Criteria:

1) Presence of ultrasonographic or magnetic resonance imaging (MRI) documented rotator cuff tear confirmed at surgery to be a medium to large-sized rotator cuff tear (> 1 cm), which requires intervention due to persistent difficulty in elevation of affected shoulder and/or pain; 2) ability to give informed consent for procedure, rehabilitation, and regular clinical and radiologic follow-up for a minimum period of 6 most post-surgery; and have 3) preoperative blood platelet counts >150,000/microliter.

Exclusion Criteria:

1) they have a type III subscapularis tear and above due to different rehabilitation protocol; 2) massive, partial, or traumatic cuff tears; 3) partial or incomplete repairs; 4) is a chronic smoker or patient with Parkinson's disease; 5) have a condition that may hinder healing or attending follow-up visits (e.g., diabetes, immunocompromised status, chemotherapy treatment, chronic steroid use); and 6) age >70.

Results on the aggregate of the sample will be published.

Patients will be randomized to either the treatment or control group using an automated randomization program using a research electronic data capture (REDCap) system prior to surgery.