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Partial Thickness Rotator Cuff Tears: Treatment

It is important to understand that not all full thickness rotator cuff tears are alike, and that some complete tears are compatible with excellent function and minimal discomfort. Armed with biomechanical models, basic engineering principles, and kinematic studies of patients with known rotator cuff tears, Burkhart defined the “functional rotator cuff tear.”

His reasoning was based on intact force couples in the transverse and coronal planes despite tearing. With the humeral head well-centered, the anatomically deficient rotator cuff tear can still provide functional integrity. A biomechanically functioning torn rotator cuff must spare a portion of the infraspinatus as well as the subscapularis. Alterations in this relationship can cause the centroid to move superiorly, thereby allowing the humeral head to translate superiorly and limiting shoulder elevation and normal kinematics.

Because not all tears are symptomatic, are there indications for the nonsurgical management of full-thickness tears? Yamaguchi has proposed three categories of risk:

Group 1: those not at risk for irreversible changes to the rotator cuff in the near future;

Group II: those at risk for irreversible changes with prolonged nonsurgical management;

Group III: those already with irreversible changes .

Irreversible changes include fatty infiltration, muscle atrophy, degenerative joint disease, and morphologic changes to the cuff including retraction and thinning. These irreversible changes in turn reflect the pre-operative risk factors portending a poorer outcome including larger tears, delay in treatment, and advanced age.

The size of the tear, degree of retraction, the presence or absence of fatty infiltration or atrophy, patient age, and activity level help the clinician determine the appropriate category, and then decisions can be made regarding the duration of nonsurgical management versus early surgical intervention. If a small tear can progress during the course of nonsurgical management but the results of treatment are not jeopardized, a prolonged conservative course may be worthwhile without posing a significant risk to the final outcome.

As noted earlier, the clinical presentation of a full-thickness rotator cuff tear can mimic findings consistent with simple impingement or with a partial thickness tear. The most common physical finding that distinguishes those with full thickness tears from impingement is weakness upon stress testing.

Although weakness may be an indication of inhibitory pain, the Neer test can help document actual tendon weakness. After pain is relieved with the subacromial injection, significant weakness on stress testing is indicative of a full thickness injury. Often in those with large, chronic tears, visible atrophy within the supraspinatus and infraspinatus fossa may be present.

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