Studies are beginning to show that early on after rotator cuff tendon repair, the tendon retracts or pulls away from the bone. In fact, this study from the well-known Cleveland Clinic reports all rotator cuff repairs pulled away from where they were sutured (stitched in place).
Special marker beads were placed in the repaired tendons of 14 patients. The surgeons used serial low-dose CT scans (repeated at six weeks, 12-weeks, 26-weeks, and one year) to check the position of the anchor beads. Since the beads were inside the tendon, this was a clear representation of the tendon position. Movement of the beads away from the bone signaled tendon retraction.
The surgeons noticed that this retraction did not always mean the tendon would tear. Only about one-third of the group developed an actual recurrent (second) tear in the damaged rotator cuff tendon.
Tendon retraction occurred early after surgery (in the first six to 12 weeks). Those patients who had the most tendon retraction were also the ones who developed a tendon defect. Defect was defined as a full-thickness, fluid-filled gap in the tendon (as seen on CT scan). The authors refer to tendon retraction without defect as a failure with continuity. Retraction and defect did not occur at the same time but rather, retraction developed first that led to the recurrent tendon tear.
Questions that come up from these findings include: 1) Why does this happen? 2) How does this affect the patient’s function? and 3) What can be done about it? The answer to the first question (why) isn’t completely clear.
A couple of clues were uncovered in this study. First, older adults were more likely to experience this tendon retraction/recurrent tear. Tendons that pull through the sutures and repairs that elongate or lengthen in the newly forming tissue during the healing process result in tendon retraction and/or defect.
And second, patients with larger defects to begin with were more likely to develop retraction leading to tendon tear. Both of these factors suggest poor tendon quality at the time of surgery as an important risk factor. These risk factors and findings naturally affect function (question number two) and speculation as to how to prevent it from happening (question number three).
They found that patients who developed a tendon retraction that led to a tendon defect did lose shoulder/arm function but not strength of the scapular (shoulder blade) muscles. Tendon retraction alone (remember: failure with continuity) did not result in loss of function.
Those findings lead to the third question: what to do about this? If tendon retraction doesn’t alter motion or function, does anything have to be done differently? The authors say ‘yes’ because one-third of the group with tendon retraction went on to develop a recurrent tear. By looking at the risk factors (older age, more severe tear) it may be possible to head the problem off at the pass, so-to-speak.
Exactly how to prevent the problem of retraction/recurrence remains unclear. Perhaps reattaching the torn tendon to a different place on the bone might help. There may be other changes in the surgical technique that could help improve the quality of repair. This would have to be studied more closely by comparing results of different suture placement and repair techniques. More study is needed to understand the mechanisms by which tendon retraction occurs in the first place.
The fact that age is a risk factor suggests that biologic characteristics of the damaged tendon are as important as the type of surgical repair. Small tears can be repaired since function is not affected by tendon retraction but medium-to-large tears should be reconstructed. Patient selection for each type of surgery becomes important as well.
And finally, the clear understanding that the problem develops early on leads to the conclusion that activity in the early days and weeks after surgery must be monitored closely. Too much activity, motion, and force on the healing tissue may contribute to tendon retraction and must be prevented. The fact that 80 per cent of all retractions occurred in the first 12 weeks highlights this as a key time period for protection of the healing tissue in all patients.