J Knee Surg 2015; 28(06): 506-512
DOI: 10.1055/s-0034-1394167
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Tibial Fixation Properties of a Continuous-Loop ACL Hamstring Graft Construct with Suspensory Fixation in Porcine Bone

Patrick A. Smith
1   Clinical Practice at Columbia Orthopaedic Group, L.L.P., Columbia, Missouri
2   Department of Orthopaedic Surgery, Missouri Orthopaedic Institute, University of Missouri, Columbia, Missouri
,
Thomas M. DeBerardino
3   Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, Connecticut
› Author Affiliations
Further Information

Publication History

14 July 2014

17 August 2014

Publication Date:
27 October 2014 (online)

Abstract

The aim of this article is to compare tibial fixation strength of suspensory fixation for a quadrupled semitendinosus continuous loop all-inside anterior cruciate ligament (ACL) construct versus a doubled semitendinosus and gracilis graft fixated with an interference screw. Biomechanical testing was conducted using human hamstring allografts and porcine tibias. Constructs were cycled from 50 to 250 N for 500 cycles followed by a pull to failure. The average load to failure of tibial suspensory fixation of the all-inside continuous loop construct (1,012 N) was statistically different compared with the tibial interference screw group (612 N) (p < 0.001). The cyclic displacement of the continuous loop construct (2.5 mm) was not statistically different from the interference screw construct (1.9 mm). For both the groups, approximately half the overall cyclic displacement occurred with the first cycle. Tibial side suspensory fixation of a novel all-inside continuous loop hamstring graft provided suitable strength for tibial fixation for ACL reconstruction. The continuous loop construct had a significantly higher load to failure compared with the use of an interference screw, and cyclic loading was comparable. Use of hamstring soft tissue grafts is very common for ACL reconstruction. An all-inside ACL reconstruction is based on a continuous loop construct utilizing a single semitendinosus graft that is quadrupled employing suspensory fixation on both the femoral and tibial side. Suspensory fixation on the femoral side been previously reported, but this is the first report of strength of this method of suspensory fixation on the tibia.