When Do Rotator Cuff Repairs Fail? Serial Ultrasound Examination After Arthroscopic Repair of Large and Massive Rotator Cuff Tears
Miller BS, Downie BK, Kohen RB, Kijek T, Lesniak B, Jacobson JA, Hughes RE, Carpenter JE. Am J Sports Med. 2011 Jul 7. [Epub ahead of print]
Rotator cuff tears occur frequently and this occurrence increases with an increase in age. Arthroscopic repair is presently the best option to improve shoulder function and decreasing pain. However, large and massive tears have been reported to have a high retear rate (13% to 94%). To better optimize the surgical repair and rehabilitation of these patients we need a better understanding of when these repairs fail. Therefore, the objective of this study was to define the timing of structural failure and to examine the association between failures and clinical outcome variables. Twenty-two patients with rotator cuff tears larger than 3 mm in size were recruited. All patients underwent arthroscopic rotator cuff repairs and rotator cuff integrity was evaluated at 2 days, 2 weeks, 6 weeks, 3 months, 6 months, 12 months, and 24 months post surgery with diagnostic ultrasound. Western Ontario Rotator Cuff (WORC) Index scores, which assess symptoms, function, and quality of life, were also collected at each time point. All patients were immobilized for three months following surgery and then standard rehabilitation was initiated starting with gentle passive motion. They found that nine (41%) of the 22 patients developed a recurrent tear. Seven of the nine occurred within 3 months post-surgery and the remaining two occurred between 3 and 6 months. At the 24-month follow-up there was a trend when comparing group WORC scores (p = 0.07) suggesting that the intact group had better shoulder function that the patients with recurrent tears.
This was a very nice study attempting to investigate when rotator cuff repairs fail to better optimize treatment options. In addition, it also won the O’Donoghue Award from the AOSSM. They found that most of the recurrent tears (7 out of 9) occurred prior to 3 months. This is before rehabilitation or any motion has occurred, which suggests several things. First that it may be a mechanical failure due to suture pull out. This may be occurring due to the amount of tension required to reapproximate the retracted tendon back to the footprint. Second, it has been shown that small muscular contractions of the rotator cuff do occur even during immobilization, which may cause insertion site failures during early healing. Third, patients may not have been completely compliant during the three months of immobilization thereby placing too much strain on the healing site. Lastly, the properties of the tendon have been shown to change based on the amount of time the tendon has been torn. This may cause suture pull out at lower loads. They also found a trend toward the intact repair group having better WORC scores at 24 months post surgery. The authors suggest that with a larger sample size this would become significant. This would suggest that the WORC score can be used clinically to detect if a recurrent tear has occurred even without ultrasound. This is encouraging however, if most tears occurred prior to 3 months and a change in function isn’t observed until 24 months then clinically much time has been wasted. Clinically, this indicates that the first 3 months are crucial to the successful repair of rotator cuff tears. As clinicians, understanding the mechanism of failed repairs will allow us to better treat and rehabilitate patients. Educating the patients about the importance of immobilization may be crucial for successful tendon to bone healing. What are your thoughts on why rotator cuff tears fail so frequently? Do you think it’s a function of surgery or rehabilitation? Can the length of immobilization play a significant role?
Written by: Stephen Thomas
Reviewed by: Jeffrey Driban
Steve: Based on the literature and your experience, what are your thoughts about the patients having their shoulder immobilized for 3 months? I feel like we used to start pendulum swings much earlier than 3 months post-op.
Jeff nice thought. It obviously varies from surgeon to surgeon but I have seen this length of immobilization in the past. There is some basic science data (https://www.ncbi.nlm.nih.gov/pubmed/17536907) that supports longer immobilization to improve tendon to bone healing of the rotator cuff. The major concern clinically for long immobilization is stiffness and atrophy. Another basic science study (https://www.ncbi.nlm.nih.gov/pubmed/18201650) demonstrated that range of motion was restored without much difficulty. Granted this was in a rat and how it transitions into humans is not known. As for the atrophy, EMG studies (https://www.ncbi.nlm.nih.gov/pubmed/15570224) have demonstrated muscle activity during immobilization. Therefore, this could limit atrophy and also still provide minimal load to the healing insertion site. Another rat study used botox to completely remove load during rotator cuff healing and found detrimental affects to the tendon. This supports the claim that there is an optimal balance of load required for rotator cuff healing.