Partial-thickness rotator cuff tear
Partial-thickness rotator cuff tears are rotator cuff tears that lack full transmural extension form the articular to the bursal surfaces.
Partial-thickness rotator cuff tears are common and occur more often with increasing age, prevalence ranges from 4% in patients under the age of 40 years and increases up to 25% in patients over the age of 60 .
Risk factors include overhead activity and throwing sports and they are also associated with subacromial impingement.
- internal impingement
- subacromial impingement
- glenohumeral instability
- repetitive overload
- hypovascularity of the distal parts of tendon and the footprint
- age-related hypocellularity and/or fascicular thinning etc.
They can be classified as follows :
- articular-sided tears: arise from undersurface part of the tendon and communicate with the glenohumeral joint space
- bursal-sided tears: arise from the bursal surface and communicate with the subacromial-subdeltoid bursa
- intrasubstance tears: confined to the tendon they also known as concealed interstitial delamination (CID)
Cadaveric studies suggest that most partial-thickness tears are intratendinous followed by articular-sided and bursal-sided tears .
They can be graded based on their depth or in relation to the tendon thickness:
- grade 1: <3 mm or <25%
- grade 2: 3-6 mm or 25-50%
- grade 3 : >6 mm or >50%
Focal hypoechoic or anechoic defect in the area of the partially torn tendon, either on the bursal or articular side with intact residual fibers .
Sensitivity and specificity is 66% and 93% when conducted by a skilled examiner .
Focal non-transmural defect of fluid signal intensity of the rotator cuff on fat-saturated PD or T2 weighted images, again with intact residual fibers .
Sensitivity and specificity is 64% and 92%.
Intraarticular contrast will extend into the tear, particularly in case of an articular-sided tear. The ABER (abduction external rotation) position is useful to demonstrate intratendinous extensions due to the lax tendon fibers and the contrast filling into the delaminated space .
Treatment and prognosis
Partial-thickness tears can be initially treated conservatively for 2-3 months. Surgery is indicated for patients, who failed conservative treatment and younger patients with a single acute injury and include debridement and repair the latter, particularly in larger tears, where more than 75% of the tendon diameter is affected . Subacromial decompression might be an option if there are extrinsic risk factors for subacromial impingement . Partial-thickness tears with intratendinous extension might need more extensive debridement or more dedicated repair.