Anchor design and bone mineral density affect the pull-out strength of suture anchors in rotator cuff repair: which anchors are best to use in patients with low bone quality?
BACKGROUND
Different metal and biodegradable suture anchors are available for rotator cuff repair. Poor bone quality may result in anchor loosening and tendon rerupture.


OBJECTIVE
Higher bone mineral density is associated with higher pull-out strength of suture anchors. Depending on anchor placement, pull-out strengths of anchors are different within the greater tuberosity.


METHODS
Cadaveric biomechanical study.


METHODS
Trabecular and cortical bone mineral densities were determined for different regions within the greater tuberosity. Metal screw-type and biodegradable hook-type anchors were cyclically loaded.


RESULTS
Mean failure load of metal and biodegradable anchors was 273 N and 162 N, respectively, for the proximal part (P < .01) and 184 N and 112 N, respectively, for the distal part (P < .01). Both types of anchors showed higher failure loads in the proximal-anterior and -middle parts of the greater tuberosity than in the distal part (P < .01). A significant positive correlation was found between cortical bone mineral density and failure load of metal anchors (P < .01).


CONCLUSIONS
Bone quality, anchor type, and anchor placement have a significant impact on anchor failure loads.


CONCLUSIONS
Suture anchors should be placed in the proximal-anterior and -middle parts of the greater tuberosity. In the distal parts, biodegradable hook-like anchors should be used with caution.
Department of Orthopaedic Surgery, University of Regensburg, Regensburg, Germany. markus.tingart@gmx.de
Markus J
MJ
Tingart
Maria
M
Apreleva
Janne
J
Lehtinen
David
D
Zurakowski
Jon J P
JJ
Warner
D000368:Aged; D001672:Biocompatible Materials; D001673:Biodegradation, Environmental; D001696:Biomechanical Phenomena; D015519:Bone Density; D002102:Cadaver; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011475:Prosthesis Failure; D017006:Rotator Cuff / Q000601:surgery*; D000070636:Rotator Cuff Injuries; D000070599:Shoulder Injuries; D012785:Shoulder Joint / Q000601:surgery*; D013536:Suture Techniques; D016896:Treatment Outcome; D016474:Weight-Bearing
D001672:Biocompatible Materials