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.

Epidemiology

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.

Pathology

Etiology
Extrinsic factors
  • internal impingement
  • subacromial impingement 
  • glenohumeral instability
  • trauma
  • repetitive overload
Intrinsic factors
  • hypovascularity of the distal parts of tendon and the footprint
  • age-related hypocellularity and/or fascicular thinning etc.
Classification

They can be classified as follows :

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%

Radiographic features

Ultrasound

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 .

MRI

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%.

MR arthrography

MR arthrography is preferred over CT arthrography since it is also able to depict bursal-sided or intrasubstance tears. Sensitivity and specificity is 86% and 96%.

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.

See also