Rotator cuff injuries, typically caused by a combination of factors, can significantly impact a patient's quality of life. Overuse or repetitive stress, common in certain sports or job activities, along with aging and degenerative changes, contribute to the vulnerability of the rotator cuff tendons. Trauma, such as falls or direct blows to the shoulder, can also lead to tears in the rotator cuff.

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The mechanism of these injuries involves impingement, where the rotator cuff tendons are compressed between the humeral head and the acromion during overhead arm movements. Tendon degeneration, characterized by the gradual breakdown of tissue, and acute or chronic tears further contribute to the complexity of rotator cuff injuries.

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Patients with rotator cuff injuries often experience persistent shoulder pain, both during arm movements and at rest. The limited range of motion, especially in activities like reaching overhead or behind the back, becomes apparent. This impaired functionality extends to daily tasks such as lifting objects, dressing, and participating in sports or recreational activities. Additionally, sleep disturbances may occur as pain interferes with the ability to find a comfortable sleeping position.

Rotator cuff tears have conventionally been addressed through surgical interventions aimed at repairing the damaged tendons, with the goal of enhancing function and alleviating pain. However, the effectiveness of surgery in achieving long-term success has been a subject of debate. Numerous studies suggest that even with advancements in surgical techniques and materials, there remains a persistently high failure rate ranging from 30% to 94% for tendon-to-bone rotator cuff repairs.

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The primary challenge underlying the failure of rotator cuff repair appears to be biologic. The intricate fibro-cartilaginous transition zone between the rotator cuff and the bone lacks the capacity for regeneration after standard repair techniques. Instead, these techniques often result in the formation of fibro-vascular scar tissue with suboptimal mechanical properties.

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Recognizing this limitation, current research focus has shifted from solely improving mechanical aspects of repair to enhancing the biological environment surrounding the repair site. This entails exploring the potential of biological therapies such as growth factors (GF), bone morphogenetic proteins (BMPs), and, notably, stem cells. The hypothesis is that these biological interventions may promote the regeneration of the normal tendon-to-bone insertion microarchitecture while limiting the formation of scar tissue.

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