Perthes lesion of the shoulder
Perthes lesion of the shoulder is one of the types of the anterior glenohumeral injury in which the anterior inferior labrum is torn and lifted from the edge of the glenoid but still attached to the intact lifted periosteum from the anterior aspect of the glenoid. Although the labrum may be normally positioned, functionally it no longer provides any stability to the humeral head, mainly as a result of impairment of the normal stabilizing influence of the inferior glenohumeral ligament.
It should not be confused with Perthes disease of the hip.
Radiographic features
As the labrum is often normally positioned it may be difficult to appreciate, especially if scarring obliterates the space deep to the labrum. The presence of joint effusion on MR arthrogram help in the detection of this lesion by demonstrating fluid extending beneath the labrum and filling the space between the elevated periosteum anteriorly and the scapula posteriorly.
Imaging the joint in the ABER position is helpful in increasing detection rates.
Treatment and prognosis
Although scarring may develop making detection both on imaging and arthroscopy difficult to interpret, the shoulder remains unstable, unless re-attachment of the labrum is performed.
History and etymology
It is named after Georg Clemens Perthes (1869-1927), German surgeon, who first described the lesion in 1905 . Perthes was also interestingly one of the first people to use radiotherapy to treat breast carcinoma .
Differential diagnosis
A number of lesions are closely related have similar appearances: see anterior glenohumeral injury for discussion of the differences.
An ALPSA lesion ("medialised Bankart") involves medial displacement of the torn labrum which is still attached to the medial scapular periosteum.
A sublabral recess can be a differential in some situations.