Secondary surgery may be necessary to achieve a functional result after tendon injury.
If the tendon(s) remain stuck, they can be freed by a tenolysis operation in which the tendon is separated from its surrounding sheath. This is often extremely difficult, and may require mobilization of scar tissue in ligaments around stiff joints. It is not always successful, and may result in recurrent adhesion and stiffness, and even occasionally rupture of the tendon.
Complete failure of flexor tendon repair with tendon rupture requires flexor tendon grafting. Scar tissue should be given 3-6 months to settle during which time as much passive movement as possible should be regained by physiotherapy. If the tendon sheath (pulley mechanism) has survived the first repair and its subsequent failure, a single stage tendon graft can be performed, but loss of the sheath requires pulley reconstruction first, using a silicone tendon rod to maintain a pathway for the tendon while the new pulley mechanism heals. The pulley is reconstructed using a small tendon graft passed around the adjacent bone and the tendon rod.
If there is no need for pulley reconstruction a single stage tendon graft can be performed, taking a spare tendon from just above the wrist if available (palmaris longus). The graft is attached to the tendon of the affected flexor muscle at the wrist level and passed through the palm and finger to emerge at the end just beneath the nail, to which it is attached. This is the strongest method of attachment available and makes tension adjustment at the end of the operation very accurate.
Because the repair is strong, early active movement under supervision of the hand therapist is possible, reducing the risk of adhesion and loss of movement. As with primary tendon repair, this is a difficult, uncomfortable and prolonged process of rehabilitation requiring fortitude and persistence on the part of the patient over a period of 8 or more weeks. Even so the result can be disappointing for around 20% of patients, and may require yet more surgery in the form of tenolysis and joint release to obtain the best result that can be achieved for that individual patient. This may not be all that is hoped for, but in most cases will be functionally acceptable.