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Friday, February 15, 2002

Bone buttons effective for rotator cuff repairs

Although allograft bone anchors can be used successfully for rotator cuff repairs, most require that the surgeon drill a hole in the humerus before inserting the anchor. This can be difficult in an arthroscopic procedure. Investigators reporting in scientific exhibit 39 examined whether a bone button might be as effective as a standard bone anchor.

Buttons, 3mm in diameter and 10mm long, were cut from cortical bone. A 3.5mm conical sharpened tip was turned on one of the ends and two radiused holes were drilled through the button for suture passage. The button was inserted directly through the metaphyseal bone to a depth of 20mm where it locked into the cancellous bone.

"Because of the pointed tip and the instrumentation used to keep the button perpendicular to the bone surface, the bone button can be tapped directly though the humeral head cortex and into cancellous bone where it locks in place without pre-drilling a hole in the bone as is typical with most anchors," noted the researchers.

Subsequently, a single surgeon performed arthroscopic repair using the bone button on 55 consecutive rotator cuff tears. One button was broken during insertion and was removed; three others were broken when insertion was attempted through dense cortical bone. By using an awl to start a pilot hole, the surgeon was subsequently able to insert the buttons successfully. All cases were followed by serial radiographs in clinical exams.

Mechanical testing of the bone buttons resulted in pullout strength of 35 pounds, which is comparable to other suture anchors. The allograft button could be successfully introduced through metaphyseal bone during arthroscopic surgery without pre-drilling. The button locked consistently in cancellous bone, did not require cortical fixation, and could be placed as close as 3mm apart.

Based on these results, investigators concluded that allograft conical bone buttons can consistently be self-introduced and locked into the humeral head during successful repair of the rotator cuff. This arthroscopic application can save significant time over surgeries that involve pre-drilling insertion holes and provide successful mechanical and radiographic results.

Investigators included Peter M. Bonutti, MD, Matthew J. Cremens, MS, (an employee of Bonutti Research, Inc.), and Frank S. Lee, MD, all of Effingham, Ill.

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2002 Academy News February 15 Index B

Last modified 08/February/2002