If your torn rotator cuff does not bother you, what's the best approach?

[mtomaino]

The issue is whether nonoperative treatment of an asymptomatic rotator cuff tear burns any bridges. First----there is recent literature by Yamaguchi et al in the Journal of Bone and Joint Surgery (2010;92:2623-2633), which suggests that pain development in shoulders with an asymptomatic rotator cuff tear is associated with an increase in tear size, and that larger tears are more likely to develop pain in the short term than smaller tears. Yamaguchi has previously published regarding the natural history of asymptomatic tears--and has shown that tear size seems to increase over time.
We also know that over time, a torn tendon can lead to fatty infiltration into the muscle itself as well as atrophy, and that this can occur over 2 or so years, and is not easily reversible after repair. Further, repair success rates appear to be inversely proportional to the extent of fatty infiltration.

Gupta et al in October's Journal of Bone and Joint Surgery (2010;92:2270-8), evaluated the effect of tenotomy in a rabbit animal model and showed that the muscular changes they found after cutting the rotator cuff tendon looked similar to the changes they observed when they cut the nerve that innervated the muscle. They opined, in light of their data and other published studies looking at the impact of retracted cuff tears on suprascapular nerve function in humans (Basmania et al J Shoulder Elbow Surg 2003; 12:497-500 and 2006; 15:395-8 ), that neuronal injury may explain the atrophy and fatty infiltration that occurs when cuff tears are large, retracted-----and not fixed at the outset.

So--if you truly have no pain, and for that matter no weakness or dysfunction-----though it may be "safest" to have a repair--so long as the tear is small, it's perfectly reasonable to "not have surgery" and follow it for progression.

Based on the above literature, use the development of symptoms as a reasonable proxy for progression. However, because of the impact of time on size progression, and the observation that chronic tears may lead to nerve dysfunction and secondary muscular changes---and because this can decrease repair success rates-- if the tear is large (but minimally painful) or small AND painful, I would advise surgical repair.