Rotator Cuff Repairs
Clinical Associate Professor
Macquarie University Hospital, Macquarie Park
Sydney Sports Medicine Centre, Homebush
Southern Orthopaedics, Wollongong
Campbelltown Private Hospital
Why do rotator cuffs tear?
The cause of rotator tears are complex. While tears were first thought to be caused by “impingement”, that is catching of the tendon on the bone, impingement is now thought to be a consequence rather than a cause of cuff tears.
Sudden tearing of a normal tendon occurs rarely. Usually the tear occurs slowly in a tendon that is weakened. Many factors contribute to this. Aging with resultant poor healing and reduce circulation in the tendon is a significant factor. There also appears to be inherited factors. Mechanical forces on the rotator cuff (such as repeated lifting) contribute to its failure.
The combination of these factors results in partial tendon tears which ultimately progress to full thickness rotator cuff tears.
A partial rotator cuff tears even on a microscopic level cause a vicious circle as each tendon fibre tears; it is subsequently under loaded throughout the length of the tendon causing degenerative changes. Subsequent the tendon elsewhere is overloaded also causing degenerative changes to the tendon. Like a fraying rope, as each strand tears, the remaining strands take up more of the weight till they all tear and a full thickness tear develops.
Over time, the full thickness tear increases in size and the tendon and muscle shortens and retracts away from its attachment. As the tears size increases, so does the retraction. The muscle then wastes away. This is an irreversible process. This is why it is important not to neglect rotator cuff tears.