Determination of fixation strength of large-diameter interference screws.
Small-diameter interference screws are a widely used method of securing bone-tendon grafts during anterior cruciate ligament reconstructive procedures. Recent reports document tunnel widening and subsequent loss of fixation, leading to a need for alternative fixation methods. In cadaver tissue, the fixation strength of large-diameter (11-, 13-, and 15-mm) interference screws was tested and compared with that of clinically used 9-mm diameter screws. Patellar-tendon sections were fashioned into three grafts, each with bone plugs measuring 10 x 20 x 7.5 mm. Tunnels were created in the epiphyseal bone of the femurs and tibias, resulting in gap sizes of 4.5-, 6.5-, 8.5-, and 10.5-mm for the 9-, 11-, 13-, and 15-mm diameter screws, respectively. Grafts were pulled from the tunnel at a rate of 51 cm/min. Average fixation strengths were 276, 302, 328, and 328 N for the 9-, 11-, 13-, and 15-mm screws, respectively. No significant difference existed between the fixation strengths (ANOVA, P < or = .05).
Matthews
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LS
Biomechanics Research Laboratory, Union Memorial Hospital, Baltimore, Maryland 21218, USA.
Parks
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BG
Sabbagh
R C
RC
D000368:Aged; D000369:Aged, 80 and over; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D001696:Biomechanical Phenomena; D001863:Bone Screws; D016025:Bone Transplantation; D005269:Femur / Q000601:surgery*; D006801:Humans; D066298:In Vitro Techniques; D017847:Patellar Ligament / Q000637:transplantation; D013977:Tibia / Q000601:surgery*