Traumatic Conditions (Other): Rotator Cuff Tear

Tendons passing out to the greater tuberosity have, for several centimetres, a synovial cavity both below and above. This leads to a watershed zone in the tendons about 1-2cm from the insertion that has a poor vascular supply and cannot react with a prompt healing response to either local acute injury or chronic wear and tear.

The process of degenerative tearing of the supraspinatus tendon in particular begins early, with up to half of the population in their fifties having a partial thickness rotator cuff tear. The population in their seventies have approximately a 1 in 3 incidence of full thickness cuff tears and many are asymptomatic [16-17]. This creates problems in the interpretation of acute injury as ultrasound scans performed in patients in their seventies reveal that at least 1 in 3 have cuff tears.

The ultrasound displays a full thickness tear (click on the scan to enlarge).

Learning bite

Following a shoulder injury, the finding of a tear may mean that the fall caused an acute strain of the cuff (perhaps already weakened by a degenerative tear) or, alternatively, that it pre-dated the fall.