All surgery carries some risk and any patient undergoing this operation will have the opportunity to discuss these during the consent process.
These risks are kept to a minimum by using regional anaesthetic techniques and keyhole surgery which, both reduce the aesthetic risks as you can maintain your own breathing supply and bloody supply to the brain during surgery. Keyhole techniques also reduce unwanted damage to tissue around the shoulder and the wounds are much smaller.
One of the common risks is developing a frozen or stiff shoulder after surgery (1 in 10), but this can be treated fairly easily in the clinic in most cases. Another potential risk is failure of the repaired tendons to heal or a further tear with subsequent injuries.