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Annals of Biomedical Engineering, Vol. 32, No. 1, January 2004 (2004), pp. 166170
The Principle of Margin Convergence in Rotator Cuff Repair as a Means of Strain Reduction at the Tear Margin
STEPHEN S. BURKHART1,2
1The Orthopaedic Institute, San Antonio, TX and 2The University of Texas Health, Science Center at San Antonio, San Antonio, TX.
(Received 23 June 2003; accepted 11 August 2003)
AbstractThe principle of margin convergence applied to rotator cuff repair is achieved by side-to-side suture of the cuff tear in order to converge the free margin of the cuff toward its bone bed. This technique dramatically reduces strain along the converged margin, thereby protecting the tendon-bone repair interface during the critical phases of healing.
KeywordsMargin convergence, Rotator cuff, Strain, Rotator cuff repair.
INTRODUCTION
Margin convergence4,5 is a term that was coined to describe what happens when a U-shaped defect in the rotator cuff tissue of the shoulder is closed side-to-side, beginning the closure with sutures at the apex of the soft tissue defect and progressing laterally with additional sutures. The free margin of the cuff converges toward the bone bed to which it needs to be repaired until at last the margin rests tension-free over the bone bed, ready for secure repair to bone with suture anchors (Fig. 1). This reduction in tension at the margin greatly enhances the stability of the repair relative to other techniques, making failure of the repair by tensile overload very unlikely. This concept may seem intuitive to an engineer, but amazingly enough it has only recently been applied in practice by orthopaedic surgeons, and it has revolutionized arthroscopic rotator cuff repair.
EVOLUTION OF THE CONCEPT
The Origin of Surgical Repair Techniques of the Rotator Cuff
The modern era of rotator cuff surgery began in the early 1900s with the work of Dr E. A. Codman of Boston, who
Address correspondence to Stephen S. Burkhart, MD, Clinical Associate Professor, The University of Texas Health Science Center at San Antonio, 540 Madison Oak Drive, Suit 620, San Antonio, TX 78258. Electronic mail: [email protected]
developed the rst techniques of surgical repair of the torn rotator cuff.7 He described rotator cuff tears as crescent-shaped defects that assume their shape due to the elasticity of the muscletendon units involved in the...