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Mechanical Performance of a Screw‐Type Veterinary Suture Anchor Subjected to Single Load to Failure and Cyclic Loads
Author(s) -
Balara Jason M.,
McCarthy Robert J.,
Boudrieau Randy J.,
Kraus Karl H.
Publication year - 2004
Publication title -
veterinary surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 79
eISSN - 1532-950X
pISSN - 0161-3499
DOI - 10.1111/j.1532-950x.2004.04084.x
Subject(s) - medicine , fibrous joint , orthodontics , veterinary medicine , surgery
Objective— To characterize the mechanical performance of a veterinary bone anchor under static and cyclic loads. Study Design— Mechanical testing study. Animals— Cadaveric canine humeri. Methods— Humeri (6 pairs) were collected from skeletally mature dogs (mean [±SD] age, 17.2±2.1 months; weight, 20.8±1.5 kg). Bone anchors were inserted in the proximal metaphysis using nylon, and were longitudinally extracted. For the opposite humerus, anchors were subjected to longitudinal cyclic load (50% of the load at failure of their pair) for 1200 cycles then longitudinally loaded to failure. Anchors were then installed in a similar and adjacent area of these 2 nd humeri with nylon and cyclically tested perpendicular to the axis of anchor insertion (100% of the longitudinal holding power of their pair) for 1200 cycles, then perpendicularly loaded to failure. Paired t‐tests were used to compare holding power before and after longitudinal cyclic testing. Results— Longitudinal holding power of the screw‐type anchor in the proximal humerus was 385±30 N. Anchor pullout was the only mode of failure. Anchors in the paired humeri did not fail after 1200 cycles of 50% longitudinal loading, and post‐cycle holding strength was not different (335±87 N; P =.32). Perpendicularly loaded anchors did not fail after 1200 cycles of 100% of opposite longitudinal holding strength, and had post‐cycle perpendicular holding strengths of 514±72 N. Suture breakage was the mode of failure. Clinical Relevance— Bone anchor holding strength is dependent on orientation of suture load. Screw‐type bone anchor holding strength was not affected by longitudinal cyclic loading, and holding strengths of approximately 385 N can be expected in metaphyseal bone of large‐breed mature dogs. Perpendicularly loaded anchors have higher failure loads, and holding strength of approximately 514 N can be expected in metaphyseal bone of the proximal humerus.