Differential suture loading in an experimental rotator cuff repair.
BACKGROUND
Repairs of large rotator cuff tears often fail to heal. A possible factor in these failures is excessive tension in the repair sutures, causing them to pull through the tendon.


OBJECTIVE
Arm positions encountered during early rehabilitation after cuff repair can dramatically increase the relative tension in the different sutures of the cuff repair.


METHODS
Controlled laboratory study.


METHODS
In a cadaver model, a 4-suture supraspinatus repair was carried out with transosseous sutures. After the repair, the arm was placed in 12 different positions. The tension in each suture was monitored using individual load cells.


RESULTS
When the arm was externally rotated relative to the plane of the scapula, the tension in the anterior suture was over 10 times that in the posterior suture (P < .001). When the arm was internally rotated, the tension in the posterior suture was over 10 times that in the anterior suture (P < .0005). When the arm was in neutral rotation, there was no significant difference in the suture tension.


CONCLUSIONS
This study is the first report of direct suture tension measurement after a model rotator cuff repair. In this model, 30 degrees of either internal or external rotation of the arm in relation to the plane of the scapula created substantial imbalances in the tension between the most anterior and most posterior sutures of a supraspinatus repair, regardless of the position of abduction.


CONCLUSIONS
Avoiding external rotation stretching during the healing of supraspinatus repairs may prevent tension overload in the critical anterior suture.
Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, Washington 98195, USA.
Christopher
C
Howe
Philippe
P
Huber
Fredric M
FM
Wolf
Frederick
F
Matsen
D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D006801:Humans; D019637:Orthopedic Procedures / Q000009:adverse effects / Q000534:rehabilitation*; D011187:Posture; D016059:Range of Motion, Articular; D017006:Rotator Cuff / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D013536:Suture Techniques; D013718:Tensile Strength; D014945:Wound Healing